Light-emitting device and display apparatus

Abstract

Provided is a light-emitting device that has favorable characteristics. A tandem-type light-emitting device according to the present invention has a first light-emitting layer and a second light-emitting layer. The first light-emitting layer includes a first light-emitting substance and a second light-emitting substance. The first light-emitting substance is a fluorescent light-emitting substance, the second light-emitting substance is a phosphorescent light-emitting substance or a TADF material, and the maximum peak wavelength of the emission spectrum of the first light-emitting substance is longer than the maximum peak wavelength of the emission spectrum of the second light-emitting substance. The second light-emitting layer includes a third light-emitting substance. The third light-emitting substance is a fluorescent light-emitting substance, and the difference between the maximum peak wavelength of the emission spectrum of the first light-emitting substance and the maximum peak wavelength of the emission spectrum of the third light-emitting substance is no more than 30 nm. The first light-emitting layer and the second light-emitting layer include a light-emitting layer that emits light in a different color gamut from a light-emitting layer of at least one of a plurality of other light-emitting devices that are to be adjacent to the light-emitting device.

Description

Light-emitting devices and displays

[0001] One embodiment of the present invention relates to a light-emitting device. Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, manufacture, or a 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, liquid crystal display devices, light-emitting devices, lighting devices, power storage devices, memory devices, imaging devices, electronic devices, and driving methods thereof or manufacturing methods thereof.

[0002] In recent years, display devices have been expected to be used in a variety of applications. For example, applications of large display devices include home television devices (also called televisions or television receivers), digital signage, and public information displays (PIDs). In addition, development of mobile information terminals, such as smartphones and tablet terminals equipped with touch panels, is progressing.

[0003] There is also a demand for higher definition display devices. Devices requiring high-definition display devices, such as devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR), are being actively developed.

[0004] As a display device, for example, a light-emitting device having a light-emitting device (also referred to as a light-emitting element) has been developed. A light-emitting device (also referred to as an EL device or an EL element) utilizing an electroluminescence (hereinafter referred to as EL) phenomenon has features such as being easily thin and lightweight, being capable of high-speed response to an input signal, and being capable of being driven by a DC constant voltage power supply, and is therefore applied to a display device.

[0005] Tandem light-emitting devices in particular have attracted attention because they achieve high current efficiency, and Patent Documents 1 and 2 disclose tandem light-emitting devices using a separate coloring method.

[0006] JP 2005-317548 A JP 2023-161850 A

[0007] An object of one embodiment of the present invention is to provide a light-emitting device with good characteristics.An object of one embodiment of the present invention is to provide a light-emitting device with good emission efficiency.An object of one embodiment of the present invention is to provide a light-emitting device with good reliability.An object of one embodiment of the present invention is to provide a light-emitting device with low driving voltage.An object of one embodiment of the present invention is to provide a light-emitting device with good reliability and low driving voltage.

[0008] Another object of one embodiment of the present invention is to provide a light-emitting device that can provide a display device with good characteristics. Another object of one embodiment of the present invention is to provide a light-emitting device that can provide a display device with good emission efficiency. Another object of one embodiment of the present invention is to provide a light-emitting device that can provide a display device with good reliability. Another object of one embodiment of the present invention is to provide a display device with low driving voltage. Another object of one embodiment of the present invention is to provide a light-emitting device that can provide a display device with low driving voltage and good reliability.

[0009] Another object is to provide any one of an organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device that consumes low power, or to provide any one of an electronic device and a lighting device that is highly reliable, or to provide any one of a novel organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device.

[0010] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these will become apparent from the description of the specification, drawings, claims, etc., and it is possible to extract other problems from the description of the specification, drawings, claims, etc.

[0011] Therefore, one aspect of the present invention provides a light-emitting device having a phosphorescent or TADF material and a fluorescent material in at least one of its light-emitting layers.

[0012] One embodiment of the present invention is a light-emitting device having a first electrode, a second electrode, an intermediate layer, a first light-emitting layer, and a second light-emitting layer, wherein the intermediate layer is located between the first electrode and the second electrode, the first light-emitting layer is located between the first electrode and the intermediate layer, and the second light-emitting layer is located between the intermediate layer and the second electrode, the first light-emitting layer has a first light-emitting material and a second light-emitting material, the first light-emitting material is a fluorescent light-emitting material, and the second light-emitting material is a phosphorescent light-emitting material or a TADF material, and a maximum peak wavelength in an emission spectrum of the first light-emitting material is the wavelength of the first light-emitting layer is longer than the maximum peak wavelength in the emission spectrum of the second light-emitting material, the second light-emitting layer has a third light-emitting material, and the third light-emitting material is a fluorescent material, the difference between the maximum peak wavelength in the emission spectrum of the first light-emitting material and the maximum peak wavelength in the emission spectrum of the third light-emitting material is 30 nm or less, and the first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of the light-emitting layer of at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device.

[0013] Another embodiment of the present invention is a light-emitting device having the above structure, in which the second light-emitting layer includes a fourth light-emitting substance, the fourth light-emitting substance being a phosphorescent material or a TADF material, and the maximum peak wavelength in the emission spectrum of the third light-emitting substance is longer than the maximum peak wavelength in the emission spectrum of the fourth light-emitting substance.

[0014] Another embodiment of the present invention is a light-emitting device including a first electrode, a second electrode, an intermediate layer, a first light-emitting layer, and a second light-emitting layer, in which the intermediate layer is located between the first electrode and the second electrode, the first light-emitting layer is located between the first electrode and the intermediate layer, and the second light-emitting layer is located between the intermediate layer and the second electrode. The first light-emitting layer includes a first light-emitting substance and a second light-emitting substance, the first light-emitting substance is a fluorescent material, and the second light-emitting substance is a phosphorescent material or a TADF material. the first light-emitting layer has a third light-emitting material, and the third light-emitting material is a fluorescent material; the difference between the maximum peak wavelength in the emission spectrum of the first light-emitting material and the maximum peak wavelength in the emission spectrum of the third light-emitting material is 30 nm or less; and the first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of the light-emitting layer of at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device.

[0015] Another embodiment of the present invention is a light-emitting device having the above structure, in which the second light-emitting layer includes a fourth light-emitting substance, and the fourth light-emitting substance is a phosphorescent material or a TADF material, and an emission edge on the short-wavelength side in an emission spectrum of the third light-emitting substance is longer than an emission edge on the short-wavelength side in an emission spectrum of the fourth light-emitting substance.

[0016] Another embodiment of the present invention is a light-emitting device including a first electrode, a second electrode, an intermediate layer, a first light-emitting layer, and a second light-emitting layer, wherein the intermediate layer is located between the first electrode and the second electrode, the first light-emitting layer is located between the first electrode and the intermediate layer, and the second light-emitting layer is located between the intermediate layer and the second electrode. The first light-emitting layer includes a first light-emitting substance and a second light-emitting substance, the first light-emitting substance is a fluorescent light-emitting substance, and the second light-emitting substance is a phosphorescent light-emitting substance or a TADF material. A maximum peak wavelength in an emission spectrum of the first light-emitting substance is the second light-emitting layer has a fourth light-emitting material, and the fourth light-emitting material is a phosphorescent material or a TADF material; the difference between the maximum peak wavelength in the emission spectrum of the first light-emitting material and the maximum peak wavelength in the emission spectrum of the fourth light-emitting material is 30 nm or less; and the first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of the light-emitting layer of at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device.

[0017] Another embodiment of the present invention is a light-emitting device including a first electrode, a second electrode, an intermediate layer, a first light-emitting layer, and a second light-emitting layer, in which the intermediate layer is located between the first electrode and the second electrode, the first light-emitting layer is located between the first electrode and the intermediate layer, and the second light-emitting layer is located between the intermediate layer and the second electrode. The first light-emitting layer includes a first light-emitting substance and a second light-emitting substance, the first light-emitting substance is a fluorescent material, and the second light-emitting substance is a phosphorescent material or a TADF material. A short-wavelength edge of an emission spectrum of the first light-emitting substance is a the wavelength of the first light-emitting layer is longer than the emission edge on the short-wavelength side in the emission spectrum of the second light-emitting material, the second light-emitting layer has a fourth light-emitting material, and the fourth light-emitting material is a phosphorescent material or a TADF material, the difference between the maximum peak wavelength in the emission spectrum of the first light-emitting material and the maximum peak wavelength in the emission spectrum of the fourth light-emitting material is 30 nm or less, and the first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of the light-emitting layer of at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device.

[0018] Another embodiment of the present invention is a light-emitting device having the above-described structures, wherein an absorption edge on the long-wavelength side in the absorption spectrum of the first light-emitting substance is longer than an emission edge on the short-wavelength side in the emission spectrum of the second light-emitting substance, and an absorption edge on the long-wavelength side in the absorption spectrum of the third light-emitting substance is longer than an emission edge on the short-wavelength side in the emission spectrum of the fourth light-emitting substance.

[0019] Another embodiment of the present invention is a light-emitting device having any of the above structures, wherein the first light-emitting layer includes a first compound and a second compound; the second light-emitting layer includes a third compound and a fourth compound; the first compound and the third compound each include a π-electron-deficient heteroaromatic ring; and the second compound and the fourth compound each include at least one of a π-electron-rich heteroaromatic ring and a triarylamine skeleton.

[0020] Another embodiment of the present invention is a light-emitting device having any of the above structures, in which the first light-emitting layer includes a first compound and a second compound, the first compound and the second compound being combined to form a first exciplex, and an emission spectrum of the first exciplex overlaps with an emission spectrum of the second light-emitting substance, and the third compound and a fourth compound being combined to form a second exciplex, and an emission spectrum of the second exciplex overlaps with an emission spectrum of the fourth light-emitting substance.

[0021] Another embodiment of the present invention is a light-emitting device having any of the above structures, wherein the first light-emitting layer includes a first compound and a second compound, and the difference between the short-wavelength emission edge of the phosphorescent spectrum of the first compound and the short-wavelength emission edge of the phosphorescent spectrum of the second compound is 30 nm or less, and the difference between the short-wavelength emission edge of the phosphorescent spectrum of the third compound and the short-wavelength emission edge of the phosphorescent spectrum of the fourth compound is 30 nm or less.

[0022] Another embodiment of the present invention is a light-emitting device having any of the above structures, which includes a first electron-transport layer and a second electron-transport layer, wherein the first electron-transport layer is located between the first light-emitting layer and the intermediate layer, the second electron-transport layer is located between the second light-emitting layer and the second electrode, the second electron-transport layer includes a fifth compound, and the fifth compound includes a triazine ring, and the intermediate layer includes a mixed layer of the sixth compound and lithium or a lithium compound, and the sixth compound includes a phenanthroline ring.

[0023] Another embodiment of the present invention is a light-emitting device in which, in each of the above structures, the first light-emitting substance and the third light-emitting substance are fluorescent substances each having a luminophore and a protecting group, the luminophore is a fused aromatic ring or a fused heteroaromatic ring, and the protecting group has any one of an alkyl group having from 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to 10 carbon atoms, and a trialkylsilyl group having from 3 to 10 carbon atoms.

[0024] Another embodiment of the present invention is a light-emitting device having any of the above structures, which includes a first hole-transport layer and a second hole-transport layer, wherein the first hole-transport layer is located between the first electrode and the first light-emitting layer, and the second hole-transport layer is located between the intermediate layer and the second light-emitting layer, and at least one of the first hole-transport layer and the second hole-transport layer includes a π-electron-rich heteroaromatic ring and an organic compound not having a triarylamine skeleton.

[0025] Another embodiment of the present invention is a light-emitting device having any of the above structures, which includes a first hole-transport layer and a second hole-transport layer, wherein the first hole-transport layer is located between the first electrode and the first light-emitting layer, the second hole-transport layer is located between the intermediate layer and the second light-emitting layer, and the first hole-transport layer includes a first layer and a second layer, the first layer is in contact with the first light-emitting layer, the first layer includes an organic compound that has a π-electron-rich heteroaromatic ring and does not have a triarylamine skeleton, and the second layer includes an organic compound that has a triarylamine skeleton.

[0026] Another embodiment of the present invention is a display device including a light-emitting device A and a light-emitting device B. The light-emitting device B emits light of a different color from the light-emitting device A. The light-emitting device A includes a first electrode A, a second electrode A, an intermediate layer A, a first light-emitting layer A, a second light-emitting layer A, a first hole-transport layer A, and a second hole-transport layer A. The intermediate layer A is located between the first electrode A and the second electrode A. The first light-emitting layer A is located between the first electrode A and the intermediate layer A. The second light-emitting layer A is located between the intermediate layer A and the second electrode A. The first hole-transport layer A is located between the first electrode A and the first a second hole transport layer A is located between the intermediate layer A and the second light-emitting layer A; the first light-emitting layer A has a first light-emitting material and a second light-emitting material, the first light-emitting material is a fluorescent light-emitting material, and the second light-emitting material is a phosphorescent material or a TADF material, and the maximum peak wavelength in the emission spectrum of the first light-emitting material is longer than the maximum peak wavelength in the emission spectrum of the second light-emitting material; the second light-emitting layer A has a third light-emitting material, and the third light-emitting material is a fluorescent light-emitting material, and the maximum peak wavelength in the emission spectrum of the first light-emitting material is longer than the maximum peak wavelength in the emission spectrum of the second light-emitting material; a difference between a maximum peak wavelength in the emission spectrum of the third luminescent material and a maximum peak wavelength in the emission spectrum of the third luminescent material is 30 nm or less; and the light-emitting device B has a first electrode B, a second electrode B, an intermediate layer B, a first luminescent layer B, a second luminescent layer B, a first hole transport layer B, and a second hole transport layer B, wherein the intermediate layer B is located between the first electrode B and the second electrode B, the first luminescent layer B is located between the first electrode B and the intermediate layer B, the second luminescent layer B is located between the intermediate layer B and the second electrode B, the first hole transport layer B is located between the first electrode B and the first luminescent layer B, and the second a hole-transporting layer B is located between the intermediate layer B and the second light-emitting layer B; the first light-emitting layer B contains a fourth light-emitting substance, and the fourth light-emitting substance is a phosphorescent light-emitting substance; the second light-emitting layer B contains a fifth light-emitting substance, and the fifth light-emitting substance is a phosphorescent light-emitting substance; a difference between a maximum peak wavelength in the emission spectrum of the fourth light-emitting substance and a maximum peak wavelength in the emission spectrum of the fifth light-emitting substance is 30 nm or less; and the first light-emitting layer A and the second light-emitting layer A have light-emitting layers that emit light in a color gamut different from those of the first light-emitting layer B and the second light-emitting layer B.

[0027] Another embodiment of the present invention is a display device including a light-emitting device A and a light-emitting device B. The light-emitting device B emits light of a different color from the light-emitting device A. The light-emitting device A includes a first electrode A, a second electrode A, an intermediate layer A, a first light-emitting layer A, a second light-emitting layer A, a first hole-transport layer A, and a second hole-transport layer A. The intermediate layer A is located between the first electrode A and the second electrode A. The first light-emitting layer A is located between the first electrode A and the intermediate layer A. The second light-emitting layer A is located between the intermediate layer A and the second electrode A. The first hole-transport layer A is located between the first electrode A and the first a second hole transport layer A is located between the intermediate layer A and the second light-emitting layer A; the first light-emitting layer A has a first light-emitting material and a second light-emitting material, the first light-emitting material is a fluorescent light-emitting material, and the second light-emitting material is a phosphorescent material or a TADF material, and the maximum peak wavelength in the emission spectrum of the first light-emitting material is longer than the maximum peak wavelength in the emission spectrum of the second light-emitting material; the second light-emitting layer A has a third light-emitting material, and the third light-emitting material is a fluorescent light-emitting material, and the maximum peak wavelength in the emission spectrum of the first light-emitting material is longer than the maximum peak wavelength in the emission spectrum of the second light-emitting material; a difference between a maximum peak wavelength in the emission spectrum of the third luminescent material and a maximum peak wavelength in the emission spectrum of the third luminescent material is 30 nm or less; and the light-emitting device B has a first electrode B, a second electrode B, an intermediate layer B, a first luminescent layer B, a second luminescent layer B, a first hole transport layer B, and a second hole transport layer B, wherein the intermediate layer B is located between the first electrode B and the second electrode B, the first luminescent layer B is located between the first electrode B and the intermediate layer B, the second luminescent layer B is located between the intermediate layer B and the second electrode B, the first hole transport layer B is located between the first electrode B and the first luminescent layer B, and the second a hole-transporting layer B located between the intermediate layer B and the second light-emitting layer B; the first light-emitting layer B containing a fourth light-emitting substance, which is a fluorescent light-emitting substance; the second light-emitting layer B containing a fifth light-emitting substance, which is a fluorescent light-emitting substance; a difference between a maximum peak wavelength in the emission spectrum of the fourth light-emitting substance and a maximum peak wavelength in the emission spectrum of the fifth light-emitting substance, which is 30 nm or less; and the first light-emitting layer A and the second light-emitting layer A each having a light-emitting layer that emits light in a color gamut different from those of the first light-emitting layer B and the second light-emitting layer B.

[0028] Another embodiment of the present invention is a light-emitting device including the light-emitting device having any of the above structures and a transistor or a substrate.

[0029] Another embodiment of the present invention is an electronic device including a light-emitting device having any of the above structures and a detection unit, an input unit, or a communication unit.

[0030] According to one embodiment of the present invention, a light-emitting device with favorable characteristics can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with favorable emission efficiency can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with favorable reliability can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with low driving voltage can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with favorable reliability and low driving voltage can be provided.

[0031] Alternatively, one embodiment of the present invention can provide a light-emitting device that can provide a display device with good characteristics. Alternatively, one embodiment of the present invention can provide a light-emitting device that can provide a display device with good emission efficiency. Alternatively, one embodiment of the present invention can provide a light-emitting device that can provide a display device with good reliability. Alternatively, one embodiment of the present invention can provide a display device with low driving voltage. Alternatively, one embodiment of the present invention can provide a light-emitting device that can provide a display device with low driving voltage and good reliability.

[0032] Alternatively, any one of an organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device with low power consumption can be provided. Alternatively, any one of an electronic device and a lighting device with high reliability can be provided. Alternatively, any one of a novel organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device can be provided.

[0033] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims.

[0034] FIGS. 1A, 1B, 1C, and 1D are diagrams illustrating light-emitting devices. FIGS. 2A, 2B, 2C, and 2D are conceptual diagrams of energy transfer between compounds in a light-emitting layer. FIG. 3 is a diagram illustrating a light-emitting device. FIGS. 4A and 4B are diagrams illustrating a light-emitting device. FIG. 5 is a diagram illustrating a light-emitting device. FIGS. 6A and 6B are diagrams illustrating a display device according to one embodiment of the present invention. FIGS. 7A and 7B are a top view and a cross-sectional view of a light-emitting device. FIGS. 8A, 8B, 8C, 8D, 8E, 8F, and 8G are top views illustrating examples of pixel configurations. FIGS. 9A, 9B, 9C, 9D, 9E, 9F, 9G, 9H, and 9I are top views illustrating examples of pixel configurations. FIGS. 10A and 10B are perspective views illustrating examples of display modules. FIGS. 11A and 11B are cross-sectional views illustrating examples of display devices. FIG. 12 is a perspective view illustrating an example of a display device configuration. FIG. 13 is a cross-sectional view showing an example of the configuration of a display device. FIG. 14 is a cross-sectional view showing an example of the configuration of a display device. FIGS. 15A, 15B, and 15C are cross-sectional views showing examples of the configuration of a display device. FIG. 16 is a cross-sectional view showing an example of the configuration of a display device. FIGS. 17A, 17B, and 17C are cross-sectional views showing examples of the configuration of a display device. FIGS. 18A, 18B, 18C, and 18D are diagrams showing examples of electronic devices. FIGS. 19A, 19B, 19C, 19D, 19E, and 19F are diagrams showing examples of electronic devices. FIGS. 20A, 20B, 20C, 20D, 20E, 20F, and 20G are diagrams showing examples of electronic devices. FIG. 21 is a diagram explaining the structure of a sample. FIG. 22 is a diagram explaining the structure of a sample. FIG. 23 is a diagram showing the luminance-current density characteristics of light-emitting devices B-1 to B-4. FIG. 24 is a diagram showing the luminance-voltage characteristics of light-emitting devices B-1 to B-4. Fig. 25 is a graph showing the current efficiency-luminance characteristics of light-emitting devices B-1 to B-4. Fig. 26 is a graph showing the current density-voltage characteristics of light-emitting devices B-1 to B-4. Fig. 27 is a graph showing the blue index (BI)-current density characteristics of light-emitting devices B-1 to B-4. Fig. 28 is a graph showing the electroluminescence spectra of light-emitting devices B-1 to B-4.FIG. 29 is a graph showing the luminance-current density characteristics of light-emitting devices G-1 to G-3. FIG. 30 is a graph showing the luminance-voltage characteristics of light-emitting devices G-1 to G-3. FIG. 31 is a graph showing the current efficiency-luminance characteristics of light-emitting devices G-1 to G-3. FIG. 32 is a graph showing the current density-voltage characteristics of light-emitting devices G-1 to G-3. FIG. 33 is a graph showing the electroluminescence spectra of light-emitting devices G-1 to G-3. FIG. 34 is a graph showing the luminance-current density characteristics of light-emitting devices R-1 and R-2. FIG. 35 is a graph showing the luminance-voltage characteristics of light-emitting devices R-1 and R-2. FIG. 36 is a graph showing the current efficiency-luminance characteristics of light-emitting devices R-1 and R-2. FIG. 37 is a graph showing the current density-voltage characteristics of light-emitting devices R-1 and R-2. FIG. 38 is a graph showing the electroluminescence spectra of light-emitting devices R-1 and R-2. FIG. 39 is a diagram showing the emission spectra of a single film of SiTrzCz2, a single film of PSiCzCz, and a mixed film. FIG. 40 is a diagram showing the emission spectra of a single film of 8mpTP-4mDBtPBfpm, a single film of βNCCP, and a mixed film. FIG. 41 is a diagram showing the emission spectra of a single film of 11mDBtBPPnfpr, a single film of PCBBiF, and a mixed film. FIG. 42 is a diagram showing the emission spectrum of SiTrzCz2. FIG. 43 is a diagram showing the emission spectrum of PSiCzCz. FIG. 44 is a diagram showing the emission spectrum of 8mpTP-4mDBtPBfpm. FIG. 45 is a diagram showing the emission spectrum of βNCCP. FIG. 46A is a diagram showing the emission spectrum of Pt(mmtBubOcz35dm4ppy-d. ６ 46B shows the absorption and emission spectra of Pt(mmtBubOcz35dm4ppy-d ６ 47A shows the emission spectrum of Ir (5mppy-d ３ ) ２ (mbfpypy-d ３ 47B shows the absorption and emission spectra of Ir(5mppy-d ３ )２ (mbfpypy-d ３ 48A shows the absorption and emission spectra of OCPG-006, and FIG. 48B shows the emission spectra of OCPG-006 and the emission spectrum of a mixed film of 11mDBtBPPnfpr and PCBBiF. FIG. 49 shows the absorption and emission spectra of v-DABNA. FIG. 50 shows the absorption and emission spectra of 2Ph-mmtBuDPhA2Anth. FIGS. 51A and 51B show the absorption and emission spectra of v-DABNA. FIG. 52 shows the luminance-current density characteristics of light-emitting devices B-5, G-4, and R-3. FIG. 53 shows the luminance-voltage characteristics of light-emitting devices B-5, G-4, and R-3. Figure 54 shows the current efficiency-luminance characteristics of light-emitting devices B-5, G-4, and R-3. Figure 55 shows the current density-voltage characteristics of light-emitting devices B-5, G-4, and R-3. Figure 56 shows the blue index (BI)-current density characteristics of light-emitting device B-5. Figure 57 shows electroluminescence spectra of light-emitting devices B-5, G-4, and R-3. Figure 58 shows the luminance-current density characteristics of light-emitting device B-6. Figure 59 shows the luminance-voltage characteristics of light-emitting device B-6. Figure 60 shows the current efficiency-luminance characteristics of light-emitting device B-6. Figure 61 shows the current density-voltage characteristics of light-emitting device B-6. Figure 62 shows the blue index (BI)-current density characteristics of light-emitting device B-6. Figure 63 shows the electroluminescence spectrum of light-emitting device B-6. FIG. 64A shows the emission spectra of a single film of SiTrzCz2-d16, a single film of PSiCzCz-d15, and a mixed film. FIG. 64B shows the emission spectra of a single film of Pt(mmtBubOcz35dm4ppy-d ６65 is a diagram showing the emission spectrum of SiTrzCz2-d16. FIG. 66 is a diagram showing the emission spectrum of PSiCzCz-d15. FIG. 67A is a diagram showing the absorption spectrum and emission spectrum of 3Ph2CzCzBN, and FIG. 67B is a diagram showing the emission spectrum of 3Ph2CzCzBN and the emission spectrum of a mixed film of SiTrzCz2 and PSiCzCz. FIG. 68A and FIG. 68B are diagrams showing the emission spectrum of 3Ph2CzCzBN.

[0035] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various changes can be made in form and detail without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0036] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted. In addition, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be assigned.

[0037] Furthermore, for ease of understanding, the position, size, range, etc. of each component shown in the drawings may not represent the actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings.

[0038] The terms "film" and "layer" can be interchangeable depending on the circumstances. For example, the term "conductive layer" can be changed to the term "conductive film." Or, for example, the term "insulating film" can be changed to the term "insulating layer."

[0039] In this specification, etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. In addition, in this specification, etc., a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure.

[0040] In this specification and the like, holes or electrons may be referred to as "carriers." Specifically, a hole injection layer or an electron injection layer may be referred to as a "carrier injection layer," a hole transport layer or an electron transport layer may be referred to as a "carrier transport layer," and a hole block layer or an electron block layer may be referred to as a "carrier block layer." Note that the above-mentioned carrier injection layer, carrier transport layer, and carrier block layer may not be clearly distinguishable from each other. Furthermore, one layer may have two or three functions among the carrier injection layer, carrier transport layer, and carrier block layer. Furthermore, the terms "injection layer," "transport layer," and "block layer" may be simply referred to as "layer." Similarly, other layers such as "light-emitting layer" and "intermediate layer" may also be referred to as "layer."

[0041] In this specification and the like, a light-emitting device (also referred to as a light-emitting element) has an EL layer between a pair of electrodes. The EL layer has at least a light-emitting layer. In this specification and the like, a light-receiving device (also referred to as a light-receiving element) has at least an active layer that functions as a photoelectric conversion layer between a pair of electrodes. In this specification and the like, one of the pair of electrodes may be referred to as a pixel electrode, and the other as a common electrode.

[0042] In this specification, the term "tapered shape" refers to a shape in which at least a portion of the side surface of the structure is inclined relative to the substrate surface. For example, it is preferable to have a region in which the angle (also called the taper angle) between the inclined side surface and the substrate surface is less than 90°. The side surface of the structure and the substrate surface do not necessarily need to be completely flat, but may be substantially planar with a slight curvature or substantially planar with a slight unevenness.

[0043] In this specification, the term "light-emitting device" includes an image display device using an organic EL device. The term "light-emitting device" may also include a module in which a connector, such as an anisotropic conductive film or a TCP (Tape Carrier Package), is attached to an organic EL device, a module in which a printed wiring board is provided at the end of a TCP, or a module in which an IC (integrated circuit) is directly mounted on an organic EL device using a COG (Chip On Glass) method. Furthermore, lighting fixtures and the like may have a light-emitting device.

[0044] In this specification and the like, the photoluminescence (PL) spectrum refers to a spectrum obtained in fluorometry by fixing the excitation wavelength of excitation light and scanning the wavelength of emission. It may also be referred to as an emission spectrum. The emission spectrum may include a fluorescent component and a phosphorescent component. In this specification and the like, an emission spectrum consisting of a fluorescent component may be particularly referred to as a fluorescence spectrum, and an emission spectrum consisting of a phosphorescent component may be particularly referred to as a phosphorescent spectrum. Furthermore, since phosphorescent materials do not exhibit fluorescence, the emission spectrum of phosphorescent materials is a phosphorescent spectrum. Furthermore, since TADF materials exhibit fluorescence by converting triplet excitation energy to singlet excitation energy at room temperature, the emission spectrum of TADF materials at room temperature is a fluorescence spectrum.

[0045] (Embodiment 1) A tandem light-emitting device has a structure in which a plurality of light-emitting units are stacked between a pair of electrodes with an intermediate layer (charge generation layer) sandwiched therebetween. Each of the plurality of light-emitting units has a light-emitting layer, and light can be emitted from any of the light-emitting layers by passing a current through them. A tandem light-emitting device having such a configuration has a significantly higher current efficiency than a non-tandem light-emitting device, and therefore can be suitably used for display devices that require high brightness display or high reliability.

[0046] Tandem light-emitting devices have multiple light-emitting layers, making it easy to produce white light. Therefore, full-color display devices using tandem light-emitting devices often use a white color filter system. Color conversion systems using a blue-emitting light-emitting layer and a color conversion layer, typically a quantum dot, have also been put to practical use.

[0047] On the other hand, some display devices using tandem light-emitting devices that employ a color-coded method for full color have also been put to practical use. Light-emitting devices using the color-coded method have no or little energy loss in the color filters or color conversion layers, making them more efficient than the two methods mentioned above.

[0048] Furthermore, it is preferable that the light-emitting layer of the tandem light-emitting device is separated from the light-emitting layer of at least one of the other adjacent light-emitting devices, or that the light-emitting layer of the tandem light-emitting device has a light-emitting layer different from the light-emitting layer of at least one of the other adjacent light-emitting devices, or that the color of light emitted by the tandem light-emitting device is different from the color of light emitted by at least one of the other adjacent light-emitting devices, or that the light-emitting material in the light-emitting layer of the tandem light-emitting device has a different composition from the light-emitting material in the light-emitting layer of at least one of the other adjacent light-emitting devices.

[0049] The light-emitting device of the present invention having the above structure can be a light-emitting device with high current efficiency, low energy loss, and favorable characteristics. A display device according to one embodiment of the present invention using such a light-emitting device can be a display device with low power consumption, high reliability, and high luminance and thus favorable visibility.

[0050] Next, a light-emitting device of one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1A illustrates a light-emitting device 130 of one embodiment of the present invention. The light-emitting device of one embodiment of the present invention is a tandem light-emitting device including an organic compound layer 103 (also referred to as an EL layer) having a first light-emitting unit 501 including a first light-emitting layer 113_1, a second light-emitting unit 502 including a second light-emitting layer 113_2, and an intermediate layer 160 between a first electrode 101 including an anode and a second electrode 102 including a cathode.

[0051] Although the present embodiment describes an example of a light-emitting device having one intermediate layer 160 and two light-emitting units, the light-emitting device may have n (n is an integer of 1 or more) intermediate layers and n+1 light-emitting units. For example, the light-emitting device 130 shown in FIG. 1B is an example of a tandem light-emitting device in which n is 2 and the light-emitting device has a first light-emitting unit 501, a first intermediate layer 160_1, a second light-emitting unit 502, a second intermediate layer 160_2, and a third light-emitting unit 503.

[0052] 1C and 1D are schematic cross-sectional views of the light-emitting layer 113, illustrating an example of the structure of the first light-emitting layer 113_1 and the second light-emitting layer 113_2 shown in Fig. 1A. In the light-emitting device of one embodiment of the present invention, at least one of the first light-emitting layer 113_1 and the second light-emitting layer 113_2 shown in Fig. 1A preferably has the structure shown in Fig. 1C or 1D, and more preferably, both of the first light-emitting layer 113_1 and the second light-emitting layer 113_2 have the structure shown in Fig. 1C or 1D.

[0053] The light-emitting layer 113 shown in FIG. 1C includes a compound 131, a compound 132, a light-emitting substance 133, and a light-emitting substance 134. The light-emitting layer 113 shown in FIG. 1D includes a compound 131, a light-emitting substance 133, and a light-emitting substance 134. Note that the compounds 131 and 132 each function as a host material. The light-emitting substance 133 is a phosphorescent material or a fluorescent material that exhibits thermally activated delayed fluorescence (TADF) (hereinafter referred to as a TADF material). The light-emitting material 134 is a fluorescent material. The light-emitting layer 113 can emit light derived from the light-emitting substance 134.

[0054] The phosphorescent material refers to a compound that exhibits phosphorescence but does not exhibit fluorescence in a temperature range from a low temperature (for example, 77 K) to room temperature (that is, 77 K to 313 K).

[0055] The TADF material is a material that has a triplet excitation energy level (T １ level) and singlet excited energy level (S １ It refers to a material that has a small difference with the triplet excited state (level) and has the function of converting energy from a triplet excited state to a singlet excited state by reverse intersystem crossing. TADF materials can upconvert a triplet excited state to a singlet excited state with a small amount of thermal energy (reverse intersystem crossing), and can efficiently emit light (fluorescence) from the singlet excited state. In addition, conditions for efficiently obtaining thermally activated delayed fluorescence include a difference of 30 nm or less between the emission end on the short wavelength side in the fluorescence spectrum and the emission end on the short wavelength side in the phosphorescence spectrum. Or, T １ Level and S １ The energy difference between the levels is preferably greater than 0 eV and not greater than 0.20 eV, and more preferably greater than 0 eV and not greater than 0.10 eV.

[0056] Furthermore, in this specification and the like, a fluorescent substance is a compound that emits light in the visible light region or near-infrared region when relaxing from a singlet excited state to a ground state. Note that in this specification and the like, unless otherwise specified, a fluorescent substance includes a TADF material.

[0057] When the light-emitting device of one embodiment of the present invention is a light-emitting device that emits green light or a light-emitting device that emits blue light, it is more preferable that at least one of the first light-emitting layer 113_1 and the second light-emitting layer 113_2 has the structure shown in FIG. 1C or FIG. 1D .

[0058] <Configuration Example 1 of Light-Emitting Layer> A specific configuration example 1 of the light-emitting layer 113 will be described. In this configuration example, the light-emitting layer 113 has a compound 131, a compound 132, a light-emitting material 133, and a light-emitting material 134, as shown in FIG. 1C. In addition, in this configuration example, a case will be described in which the light-emitting material 133 is a phosphorescent material, and the light-emitting material 134 is a fluorescent material that is not a TADF material. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is as shown in FIG. 2A. Note that the notations and symbols in FIG. 2A are as follows. Comp(131): Compound 131 Comp(132): Compound 132 Comp(133): Light-emitting material 133 Guest(134): Light-emitting material 134 S Ｃ１ : The lowest singlet excited energy level of compound 131 (S １ level) ・T Ｃ１ : The lowest triplet excited energy level of compound 131 (T １ Level) ・S Ｃ２ : Compound 132 S １ Level / T Ｃ２ : Compound 132 T １ Rank S Ｅ : S of the exciplex １ Level / T Ｅ : T of the exciplex １ Level / T Ｃ３ : T of luminescent material 133 １ Rank S Ｇ : S of the luminescent material 134 １ Level / T Ｇ : T of luminescent material 134 １ Rank

[0059] In addition, T １As an index of the level, a phosphorescent component (phosphorescent spectrum) in a PL spectrum observed at a low temperature (for example, any temperature in the range of 4 K to 80 K) may be used. For example, a PL spectrum (phosphorescent spectrum) is measured at a measurement temperature of 10 K, and the energy at the emission edge on the short wavelength side in the phosphorescent spectrum is expressed as T １ The T level of the phosphorescent material can be considered as １ An absorption spectrum measured at room temperature can also be used as an index of the level. For example, an absorption spectrum is measured at room temperature, and the energy at the absorption edge on the long wavelength side is calculated as T １ It can also be considered as a level. １ As an index of the level, a PL spectrum measured at a low temperature (for example, any temperature in the range of 4 K to 80 K) or at room temperature may be used. For example, a PL spectrum is measured at room temperature, and the energy at the emission edge on the short wavelength side is calculated as S １ In addition, when a fluorescence spectrum and a phosphorescence spectrum are observed in a PL spectrum measured at low temperatures, the energy at the emission edge on the shortest wavelength side of the PL spectrum (fluorescence spectrum) can be regarded as S １ In addition, the S level of the fluorescent material １ An absorption spectrum measured at room temperature can also be used as an index of the level. For example, an absorption spectrum is measured at room temperature, and the energy at the absorption edge on the long wavelength side is expressed as S １ It can also be considered as a level.

[0060] The emission end on the short wavelength side of the PL spectrum can be calculated by drawing a tangent at the value where the slope on the short wavelength side of the peak (or shoulder peak) observed at the shortest wavelength in the PL spectrum is maximum, and then calculating from the intersection of the tangent with the horizontal axis (wavelength) or the baseline. The emission end on the short wavelength side of the fluorescence spectrum and the emission end on the short wavelength side of the phosphorescence spectrum can be calculated in a similar manner. The emission end on the long wavelength side of the absorption spectrum can be calculated by drawing a tangent at the value where the slope on the long wavelength side of the peak (or shoulder peak) observed at the longest wavelength in the absorption spectrum is minimum (maximum in absolute value), and then calculating from the intersection of the tangent with the horizontal axis (wavelength) or the baseline.

[0061] The combination of Compound 131 and Compound 132, which function as host materials, is preferably a combination capable of forming an exciplex (also referred to as an exciplex), and more preferably, one of them is a compound having hole-transporting properties and the other is a compound having electron-transporting properties. In this case, a donor-acceptor type exciplex is easily formed, and the exciplex can be efficiently formed. Furthermore, when Compound 131 and Compound 132 are a combination of a compound having hole-transporting properties and a compound having electron-transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the ratio of the compound having hole-transporting properties to the compound having electron-transporting properties is preferably in the range of 1:9 to 9:1 (weight ratio). Furthermore, since this configuration allows for easy control of the carrier balance, the carrier recombination region can also be easily controlled.

[0062] Examples of compounds having hole transport properties include compounds having either or both of a π-electron-rich heteroaromatic ring and a triarylamine skeleton, and examples of compounds having electron transport properties include compounds having a π-electron-deficient heteroaromatic ring.

[0063] In addition, as a combination of host materials that efficiently form an exciplex, it is preferable that the HOMO level of one of Compound 131 and Compound 132 is higher than the HOMO level of the other and the LUMO level of one is higher than the LUMO level of the other. Note that the HOMO level of Compound 131 may be equivalent to the HOMO level of Compound 132, or the LUMO level of Compound 131 may be equivalent to the LUMO level of Compound 132.

[0064] The LUMO level and HOMO level of a compound can be derived from the electrochemical properties (reduction potential and oxidation potential) of the compound measured by cyclic voltammetry (CV) measurement or the like.

[0065] The formation of an exciplex can be confirmed, for example, by comparing the emission spectra of Compound 131, Compound 132, and a mixed film obtained by mixing these materials, and observing the phenomenon that the emission spectrum of the mixed film is shifted to longer wavelengths than the emission spectra of each material (or has a new peak on the longer wavelength side). Alternatively, the formation of an exciplex can be confirmed by comparing the transient photoluminescence (PL) of Compound 131, the transient PL of Compound 132, and the transient PL of a mixed film obtained by mixing these materials, and observing differences in transient response, such as the transient PL lifetime of the mixed film having a longer-lifetime component or a larger proportion of delayed components than the transient PL lifetimes of the individual materials. The above-mentioned transient PL may also be interpreted as transient electroluminescence (EL). That is, the formation of an exciplex can also be confirmed by comparing the transient EL of Compound 131, the transient EL of Compound 132, and the transient EL of a mixed film obtained by mixing these materials, and observing differences in transient response.

[0066] As shown in FIG. 2A, the S １ Level (S Ｅ ) and the T of the exciplex １ Level (T Ｅ ) are adjacent energy levels (Route A in FIG. 2A) １ reference).

[0067] The excited energy level of the exciplex formed by Compound 131 and Compound 132 (S Ｅ and T Ｅ ) is the S of each substance (compound 131 and compound 132) that forms an exciplex. １ Level (S Ｃ１ and S Ｃ２ ) is lower than that of the luminescent element, it is possible to form an excited state with lower excitation energy, thereby reducing the driving voltage of the light-emitting device.

[0068] The correlation between the energy levels of Compound 131 and Compound 132 is not limited to that shown in FIG. 2A. １ Level (S Ｃ１ ) is S of compound 132 １ Level (S Ｃ２) or lower. １ Level (T Ｃ１ ) is the T of compound 132 １ Level (T Ｃ２ ) may be higher or lower than T Ｃ１ and T Ｃ２ The small difference in T is preferable because it is difficult for excitation energy to be biased toward one of the organic compounds, preventing one of them from being significantly deteriorated, and improving the reliability of the light-emitting device. Ｃ１ and T Ｃ２ The difference between the emission edge on the short wavelength side in the phosphorescence spectrum of Compound 131 and the emission edge on the short wavelength side in the phosphorescence spectrum of Compound 132 is preferably 0.20 eV or less, preferably 0.15 eV or less, and more preferably 0.10 eV or less. Alternatively, the difference between the emission edge on the short wavelength side in the phosphorescence spectrum of Compound 131 and the emission edge on the short wavelength side in the phosphorescence spectrum of Compound 132 is preferably 30 nm or less. When Compound 131 and Compound 132, which are a combination that forms an exciplex, have such a relationship, the reliability of the light-emitting device can be improved.

[0069] Since the luminescent material 133 is a phosphorescent luminescent material, as shown in FIG. 2A, the S １ Level (S Ｅ ) and T of the exciplex １ Level (T Ｅ ) from the above, both the singlet excitation energy and the triplet excitation energy rapidly increase to the T １ Level (T ｃ３ ) (Route A ２ ). Route A ２ In the above, the exciplex functions as an energy donor, and the luminescent material 133 functions as an energy acceptor.

[0070] Route A ２ In this case, T Ｅ ≧T Ｃ３It is preferable that the emission spectrum of the exciplex formed by the compounds 131 and 132 overlaps with the emission spectrum of the light-emitting substance 133. This is because the excitation energy of the energy donor and the excitation energy of the light-emitting substance 133 are close to each other, thereby enabling a reduction in the driving voltage of the light-emitting device. Therefore, it is preferable that the difference between the maximum peak wavelength of the emission spectrum of the exciplex formed by the compounds 131 and 132 and the maximum peak wavelength of the emission spectrum of the light-emitting substance 133 is 30 nm or less. Alternatively, it is preferable that the difference between the wavelength of the short-wavelength emission edge in the emission spectrum of the exciplex formed by the compounds 131 and 132 and the wavelength of the short-wavelength emission edge in the emission spectrum of the light-emitting substance is 30 nm or less, since this enables a reduction in the driving voltage of the light-emitting device.

[0071] The emission spectrum of the exciplex formed by Compound 131 and Compound 132 is preferably measured using a mixed film of Compound 131 and Compound 132. The sample form when measuring the emission spectrum of the light-emitting substance 133 may be a thin film or a solution, but a solution is preferred from the viewpoint of verifying the state of isolated molecules. The solvent for the solution is not particularly limited as long as the same solvent is used for comparison, but a solvent with relatively low polarity, such as toluene or chloroform, is preferred.

[0072] As shown in FIG. 2A, the triplet excitation energy of the luminescent material 133 is converted into the singlet excitation energy of the luminescent material 134, which is a fluorescent luminescent material that is not a TADF material (Route A). ３ ). Route A ３ In the structure, the luminescent material 133 functions as an energy donor, and the luminescent material 134 functions as an energy acceptor.

[0073] By using a phosphorescent material as the luminescent material 133, the T １ From the level to the energy acceptor S １ Therefore, the triplet excitation energy of the light-emitting material 133 is transferred along route A. ３ The guest material S １ Level (SＧ ) can be moved to

[0074] Route A ３ In this case, T Ｃ３ ≧S Ｇ It is preferable that the maximum peak wavelength in the emission spectrum (fluorescence spectrum) of the light-emitting substance 134 is longer than the maximum peak wavelength in the emission spectrum (phosphorescence spectrum) of the light-emitting substance 133. It is also preferable that the emission edge on the short wavelength side in the emission spectrum (fluorescence spectrum) of the light-emitting substance 134 is longer than the emission edge on the short wavelength side in the emission spectrum (phosphorescence spectrum) of the light-emitting substance 133. It is also preferable that the absorption edge on the long wavelength side in the absorption spectrum of the light-emitting substance 134 is longer than the emission edge on the short wavelength side in the emission spectrum (phosphorescence spectrum) of the light-emitting substance 133. It is also preferable that the emission edge on the short wavelength side in the phosphorescence spectrum of the light-emitting substance 134 is longer than the absorption edge on the long wavelength side in the absorption spectrum of the light-emitting substance 133. It is also preferable that the emission edge on the short wavelength side in the phosphorescence spectrum of the light-emitting substance 134 is longer than the emission edge on the short wavelength side in the emission spectrum (phosphorescence spectrum) ... With such a relationship, the triplet excitation energy of the light-emitting substance 133 is efficiently converted into the S １ This is preferable because it moves to a lower level.

[0075] However, as shown in FIG. 2A, in the light-emitting layer 113 of the light-emitting device shown in this configuration example, in addition to the above, the triplet excitation energy of the light-emitting material 133 is higher than the T １ Path to move to the level (Route A ４ In this example configuration, in which a fluorescent material other than a TADF material is used as the luminescent material 134, such energy transfer (Route A) can occur. ４ When this occurs, the light-emitting material 134 cannot contribute triplet excitation energy to light emission, and the light-emitting efficiency of the light-emitting device decreases.

[0076] Generally, the Förster mechanism (dipole-dipole interaction) and the Dexter mechanism (electron exchange interaction) are known as intermolecular energy transfer mechanisms. The Dexter mechanism occurs predominantly when the distance between the energy donor compound and the energy acceptor compound is 1 nm or less. Therefore, the Dexter mechanism is more likely to occur when the concentration of the energy acceptor compound is high. Therefore, as in this configuration example, when the light-emitting substance 134, which is the energy acceptor, is a fluorescent material with a low triplet excitation energy level and its concentration is high, the triplet excitation energy of the light-emitting substance 133, which is the energy donor, is transferred via route A by the Dexter mechanism. ４ The energy transfer and subsequent non-radiative deactivation become dominant. ４ In order to suppress this, it is more preferable to increase the distance between the light-emitting material 133 and the light-emitting material 134 to such an extent that energy transfer by the Dexter mechanism is unlikely to occur.

[0077] In addition, the T of the luminescent material 134, which is the energy acceptor, １ Level (T Ｇ ) is often an energy level derived from the luminophore contained in the luminescent material 134. ４ In order to suppress this, it is more preferable to increase the distance between the luminescent material 133 and the luminophore possessed by the luminescent material 134 .

[0078] A common method for increasing the distance between the energy donor and the luminophore possessed by the energy acceptor is to reduce the concentration of the energy acceptor in the mixed film. However, reducing the concentration of the energy acceptor inhibits not only the energy transfer from the energy donor to the energy acceptor based on the Dexter mechanism, but also the energy transfer based on the Förster mechanism. In this case, Route A ３ However, since this is based on the Förster mechanism, problems such as a decrease in the light-emitting efficiency or reliability of the light-emitting device arise.

[0079] Therefore, it is preferable that the light-emitting substance 134, which is the energy acceptor, is a compound having a luminophore as part of its structure and a protecting group that has the function of increasing the distance between the luminophore and another energy donor. When the distance between the energy donor and the energy acceptor is 1 nm or less, the Dexter mechanism prevails, and when the distance is 1 nm or more and 10 nm or less, the Förster mechanism prevails. Therefore, the protecting group is preferably a bulky substituent that extends from the luminophore in a range of 1 nm or more and 10 nm or less. By using such a compound as the light-emitting substance 134, it is possible to increase the rate of energy transfer by the Förster mechanism while suppressing energy transfer by the Dexter mechanism even when the concentration of the light-emitting substance 134 is increased. That is, the S of the light-emitting substance 133 to the light-emitting substance 134 is increased. １ Level (S Ｇ ) to the triplet excitation energy transfer (Route A ３ ) is more likely to occur, while the T １ Level (T Ｇ Triplet excitation energy transfer to (Route A) ４ : Energy transfer by the Dexter mechanism) can be made less likely to occur, and route A ４ By suppressing the decrease in luminous efficiency due to the energy transfer, the luminous efficiency of the light-emitting device can be increased.

[0080] Furthermore, in this configuration example, by increasing the concentration of the light-emitting material 134, which is an energy acceptor, it is possible to increase the rate of energy transfer via the Förster mechanism while suppressing energy transfer via the Dexter mechanism. Increasing the rate of energy transfer via the Förster mechanism shortens the excitation lifetime of the energy acceptor in the light-emitting layer, thereby improving the reliability of the light-emitting device. Specifically, the concentration of the light-emitting material 134 in the light-emitting layer 113 is preferably 2 wt % to 50 wt %, more preferably 4 wt % to 30 wt %, and even more preferably 4 wt % to 20 wt %, relative to the light-emitting material 133, which is an energy donor.

[0081] In this specification, the above-mentioned Route A １ and Route A２ This pathway is also referred to as Exciplex-Triple Energy Transfer (ExTET), which indicates that excitation energy is donated from the exciplex to the light-emitting substance 133 in the light-emitting layer 113 in this specification.

[0082] <Configuration Example 2 of Light-Emitting Layer> Next, a specific configuration example 2 of the light-emitting layer 113 will be described. In this configuration example, the light-emitting layer 113 has a compound 131, a compound 132, a light-emitting material 133, and a light-emitting material 134, as shown in FIG. 1C. In addition, in this configuration example, the light-emitting material 133 is a phosphorescent material, and the light-emitting material 134 is a fluorescent material, particularly a TADF material. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is as shown in FIG. 2B. Note that the notations, symbols, and route A in FIG. 2B １ and Route A ２ is the same as in FIG. 2A, and therefore will not be described again.

[0083] Route A shown in FIG. ２ The triplet excitation energy transferred from the exciplex formed by Compound 131 and Compound 132 to the luminescent material 133 is converted into the singlet excitation energy of the luminescent material 134, which is a TADF material (Route A ５ ).

[0084] By using a phosphorescent material as the luminescent material 133, the T １ From the level to the energy acceptor S １ Therefore, the triplet excitation energy of the light-emitting material 133 is transferred along route A. ５ The guest material S １ Level (S Ｇ ) can be moved to

[0085] Route A ５ In this case, T Ｃ３ ≧S ＧIt is preferable that the maximum peak wavelength in the emission spectrum (fluorescence spectrum) of the light-emitting substance 134 is longer than the maximum peak wavelength in the emission spectrum (phosphorescence spectrum) of the light-emitting substance 133. It is also preferable that the emission edge on the short wavelength side in the emission spectrum (fluorescence spectrum) of the light-emitting substance 134 is longer than the emission edge on the short wavelength side in the emission spectrum (phosphorescence spectrum) of the light-emitting substance 133. It is also preferable that the absorption edge on the long wavelength side in the absorption spectrum of the light-emitting substance 134 is longer than the emission edge on the short wavelength side in the emission spectrum (fluorescence spectrum) of the light-emitting substance 133. It is also preferable that the emission edge on the short wavelength side in the phosphorescence spectrum of the light-emitting substance 134 is longer than the absorption edge on the long wavelength side in the absorption spectrum of the light-emitting substance 133. It is also preferable that the emission edge on the short wavelength side in the phosphorescence spectrum of the light-emitting substance 134 is longer than the emission edge on the short wavelength side in the emission spectrum (phosphorescence spectrum) of the light-emitting substance 133. With such a relationship, the triplet excitation energy of the light-emitting substance 133 is efficiently converted into the S １ This is preferable because it moves to a lower level.

[0086] In addition, in the light-emitting layer 113 shown in this configuration example, route A ５ In addition, the triplet excitation energy of the luminescent material 133 is T １ (Route A in Figure 2B) ６ In this example, the light-emitting material 134 is a TADF material, which has the function of converting triplet excitation energy into singlet excitation energy by upconversion. ６ The triplet excitation energy converted by ７ ), exhibiting thermally activated delayed fluorescence. Therefore, the light-emitting substance 134 can efficiently emit light from the singlet excited state, thereby improving the luminous efficiency of the light-emitting device. ５ and Route A ６ In the structure, the luminescent material 133 functions as an energy donor, and the luminescent material 134 functions as an energy acceptor.

[0087] In Configuration Example 2, the light-emitting substance 133 may be a TADF material. When the light-emitting substance 133 is a TADF material, the TADF material has a function of converting triplet excitation energy into singlet excitation energy by upconversion, and therefore the singlet excitation energy of the light-emitting substance 133 can be quickly transferred to the light-emitting substance 134.

[0088] In the first and second structural examples, the light-emitting layer 113 includes four compounds (compound 131, compound 132, light-emitting substance 133, and light-emitting substance 134). However, one embodiment of the present invention is not limited to this. In the following structural examples 3 and 4, a structure in which the light-emitting layer 113 includes three compounds (compound 131, light-emitting substance 133, and light-emitting substance 134) will be described.

[0089] <Configuration Example 3 of Light-Emitting Layer> A specific configuration example 3 of the light-emitting layer 113 will be described. In this configuration example, the light-emitting layer 113 has a compound 131, a light-emitting substance 133, and a light-emitting substance 134, as shown in FIG. 1D. In addition, in this configuration example, a case will be described in which the light-emitting substance 133 is a phosphorescent light-emitting substance and the light-emitting substance 134 is a fluorescent light-emitting substance. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is as shown in FIG. 2C. Note that the notations and symbols in FIG. 2C are as follows. Comp(131): Compound 131 Comp(133): Light-emitting substance 133 Guest(134): Light-emitting substance 134 S Ｃ１ : Compound 131 S １ Level / T Ｃ１ : Compound 131 T １ Level / T Ｃ３ : T of luminescent material 133 １ Level / T Ｇ : T of luminescent material 134 １ Rank S Ｇ : S of the luminescent material 134 １ Rank

[0090] In this example, singlet excitons and triplet excitons are generated mainly by carrier recombination in the compound 131. Ｃ３ ≦T Ｃ１By selecting a phosphorescent material having the relationship Ｃ３ (Route A in Figure 2C) １８ ) Note that some of the carriers may also recombine in the light-emitting material 133.

[0091] Route A shown in FIG. 2C １８ The triplet excitation energy transferred from compound 131 to luminescent material 133 by the above reaction is converted into singlet excitation energy of luminescent material 134 (Route A １９ ).

[0092] By using a phosphorescent material as the luminescent material 133, the T １ From the level to the energy acceptor S １ Therefore, the triplet excitation energy of the light-emitting material 133 is transferred along route A. １８ The guest material S １ Level (S Ｇ ) can be moved to

[0093] Route A １８ In this case, T Ｃ３ ≧S ＧIt is preferable that the maximum peak wavelength in the emission spectrum (fluorescence spectrum) of the light-emitting substance 134 is longer than the maximum peak wavelength in the emission spectrum (phosphorescence spectrum) of the light-emitting substance 133. It is also preferable that the emission edge on the short wavelength side in the emission spectrum (fluorescence spectrum) of the light-emitting substance 134 is longer than the emission edge on the short wavelength side in the emission spectrum (phosphorescence spectrum) of the light-emitting substance 133. It is also preferable that the absorption edge on the long wavelength side in the absorption spectrum of the light-emitting substance 134 is longer than the emission edge on the short wavelength side in the emission spectrum (phosphorescence spectrum) of the light-emitting substance 133. It is also preferable that the emission edge on the short wavelength side in the phosphorescence spectrum of the light-emitting substance 134 is longer than the absorption edge on the long wavelength side in the absorption spectrum of the light-emitting substance 133. It is also preferable that the emission edge on the short wavelength side in the phosphorescence spectrum of the light-emitting substance 134 is longer than the emission edge on the short wavelength side in the emission spectrum (phosphorescence spectrum) ... With such a relationship, the triplet excitation energy of the light-emitting substance 133 is efficiently converted into the S １ This is preferable because it moves to a lower level.

[0094] However, in the light-emitting layer 113 of the light-emitting device shown in this configuration example, Route A １９ In addition, the triplet excitation energy of the luminescent material 133 is T １ The pathway to move to the level (Route A in Figure 2C) ２０ ) may also compete with

[0095] If the luminescent material 134 is not a TADF material, such energy transfer (Route A ２０ When such an energy transfer (Route A) occurs, the light-emitting material 134 cannot contribute triplet excitation energy to light emission, and the light-emitting efficiency of the light-emitting device decreases. ２０), it is important that the distance between the luminescent substance 133 and the luminescent substance 134, i.e., the distance between the luminescent substance 133 and the luminophore contained in the luminescent substance 134, is long, as explained in the above-mentioned Structural Example 1. Therefore, as explained in the above-mentioned Structural Example 1, the luminescent substance 134, which is the energy acceptor, is preferably a compound having a luminophore in part of its structure and a protecting group having the function of increasing the distance between the luminophore and another energy donor. By using such a compound as the luminescent substance 134, the S of the luminescent substance 134 can be reduced from the luminescent substance 133. １ Level (S Ｇ ) to the triplet excitation energy transfer (Route A １９ ) is more likely to occur, while the T １ Level (T Ｇ Triplet excitation energy transfer to (Route A) ２０ : Energy transfer by the Dexter mechanism) can be made less likely to occur, and route A ２０ This makes it possible to improve the luminous efficiency of the light-emitting device while suppressing the decrease in luminous efficiency that accompanies the energy transfer.

[0096] Alternatively, it is preferable that the light-emitting material 134 is a TADF material, particularly a fluorescent light-emitting material. As described in the above configuration example 2, when the light-emitting material 134 is a TADF material, it has the function of converting triplet excitation energy into singlet excitation energy by upconversion. Therefore, the triplet excitation energy is converted into singlet excitation energy by upconversion, and thermally activated delayed fluorescence is exhibited. Therefore, the light-emitting material 134 can efficiently exhibit light emission from the singlet excitation state, thereby improving the luminous efficiency of the light-emitting device.

[0097] <Configuration Example 4 of Light-Emitting Layer> In this configuration example, the light-emitting layer 113 in the light-emitting device has a compound 131, a light-emitting material 134, and a light-emitting material 133, as shown in FIG. 1D. This configuration example also shows a case where the light-emitting material 133 is a TADF material, and the light-emitting material 134 is a fluorescent material that is not a TADF material. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is as shown in FIG. 2D. The notations and symbols in FIG. 2D are the same as those in FIG. 2C, and the rest are as shown below. -S Ｃ３ : S of luminescent material 133 １ Rank

[0098] In this example, singlet excitons and triplet excitons are generated mainly by carrier recombination in the compound 131. Ｃ３ ≦S Ｃ１ And T Ｃ３ ≦T Ｃ１ By selecting a TADF material having the relationship, both the singlet excitation energy and the triplet excitation energy generated in the compound 131 can be converted into the S of the luminescent material 133. Ｃ３ and T Ｃ３ (Route A in Figure 2D) ２１ ) Note that some of the carriers may also recombine in the light-emitting material 133.

[0099] Since the light-emitting material 133 is a TADF material, it has a function of converting triplet excitation energy into singlet excitation energy by upconversion (Route A in FIG. 2D). ２２ In addition, the singlet excitation energy of the light-emitting material 133 can be rapidly transferred to the light-emitting material 134 (Route A in FIG. 2D). ２３ ).

[0100] Route A ２３ In S Ｃ３ ≧S ＧIt is preferable that the maximum peak wavelength in the emission spectrum (fluorescence spectrum) of the light-emitting substance 134 is longer than the maximum peak wavelength in the emission spectrum (fluorescence spectrum) of the light-emitting substance 133. It is preferable that the emission edge on the short wavelength side of the emission spectrum (fluorescence spectrum) of the light-emitting substance 134 is longer than the emission edge on the short wavelength side of the emission spectrum (fluorescence spectrum) of the light-emitting substance 133. It is preferable that the absorption edge on the long wavelength side of the absorption spectrum of the light-emitting substance 134 is longer than the emission edge on the short wavelength side of the emission spectrum (fluorescence spectrum) of the light-emitting substance 133. It is preferable that the emission edge on the short wavelength side of the phosphorescence spectrum of the light-emitting substance 134 is longer than the absorption edge on the long wavelength side of the absorption spectrum of the light-emitting substance 133. It is preferable that the emission edge on the short wavelength side of the phosphorescence spectrum of the light-emitting substance 134 is longer than the emission edge on the short wavelength side of the emission spectrum (fluorescence spectrum) of the light-emitting substance 133.

[0101] In the light-emitting layer 113 of the light-emitting device shown in this configuration example, route A in FIG. ２１ , Route A ２２ , and root A ２３ By taking the route shown in FIG. 1, the triplet excitation energy generated in the luminescent material 133 can be converted into fluorescent light emitted by the luminescent material 134. ２３ In the light-emitting layer 113 of the light-emitting device shown in this example, the triplet excitation energy of the light-emitting material 133 is equal to the T １ The pathway to move to the level (Route A in Figure 2D) ２４ ) may also compete with

[0102] Such energy transfer (Route A) ２４ When this type of energy transfer (Route A) occurs, the luminescent material 134, which is a fluorescent luminescent material that is not a TADF material, cannot contribute triplet excitation energy to light emission, resulting in a decrease in the luminous efficiency of the light-emitting device. ２０), it is important that the distance between the luminescent substance 133 and the luminescent substance 134, i.e., the distance between the luminescent substance 133 and the luminophore possessed by the luminescent substance 134, is long, as explained in the above-mentioned Structural Example 1. Therefore, as explained in the above-mentioned Structural Example 1, the luminescent substance 134, which is the energy acceptor, is preferably a compound having a luminophore in part of its structure and a protecting group having the function of lengthening the distance between the luminophore and another energy donor. By using such a compound as the luminescent substance 134, it is possible to prevent the S of the luminescent substance 134 from being transferred from the luminescent substance 133. １ Level (S Ｇ ) to the triplet excitation energy transfer (Route A ２３ ) is more likely to occur, while the T １ Level (T Ｇ Triplet excitation energy transfer to (Route A) ２４ : Energy transfer by the Dexter mechanism) can be made less likely to occur, so route A ２４ This can improve the luminous efficiency of the light-emitting device while suppressing the decrease in luminous efficiency due to the energy transfer, and also improve the reliability of the light-emitting device.

[0103] 2A to 2D , and these structures can be combined as appropriate. Specifically, for example, a compound capable of forming an exciplex is used as a host material, a TADF material is used as the light-emitting substance 133, and a TADF material or a fluorescent light-emitting substance other than a TADF material is used as the light-emitting substance 134.

[0104] Next, specific examples of a host material that can be used as Compound 131 and Compound 132 in the light-emitting device of one embodiment of the present invention, a phosphorescent material that can be used as the light-emitting material 133, a fluorescent material (excluding a TADF material) that can be used as the light-emitting material 134, and a TADF material that can be used as the light-emitting material 133 or the light-emitting material 134 will be described.

[0105] <<Specific Example of Host Material>> As the host material, it is preferable to use a carrier transporting material such as a compound having hole transporting properties or a compound having electron transporting properties. Furthermore, as described above, when Compound 131 and Compound 132 are used in the light-emitting layer, the combination thereof is preferably a combination capable of forming an exciplex, and it is more preferable that one of them is a compound having hole transporting properties and the other is a compound having electron transporting properties. Examples of compounds having hole transporting properties include compounds having either or both of a π-electron-rich heteroaromatic ring and a triarylamine skeleton, and examples of compounds having electron transporting properties include compounds having a π-electron-deficient heteroaromatic ring.

[0106] In this specification and the like, a triarylamine skeleton refers to a skeleton in which three aryl groups are bonded to a nitrogen atom, and the three aryl groups are not bonded to each other. A specific example of an organic compound having a triarylamine skeleton is triphenylamine.

[0107] As a compound having a π-electron-rich heteroaromatic ring that can be used as a host material, a compound having a carbazole ring is preferred because of its high hole transport property. The compound having a carbazole ring preferably has multiple carbazole rings. The compound having a carbazole ring may also have one or more elements such as silicon, boron, oxygen, and sulfur.

[0108] Furthermore, compounds having an azine ring are preferred as compounds having a π-electron-deficient heteroaromatic ring that can be used as a host material. Examples of azine rings include pyridine rings, pyrimidine rings, and triazine rings. These can improve electron transport properties. Furthermore, it is preferred to use a compound in which a carbazole ring is bonded to the azine ring directly or via an arylene group, and it is preferable to have multiple carbazole rings. As such, the presence of a carbazole ring can adjust the carrier transport properties. Furthermore, compounds having a heteroaromatic ring may have one or more elements such as silicon, boron, oxygen, and sulfur.

[0109] Furthermore, when the compound having a π-electron-deficient heteroaromatic ring or the compound having a π-electron-rich heteroaromatic ring has a group having Si (silicon), such as a triphenylsilyl group, the intermolecular distance can be increased and the thermal stability of the light-emitting layer can be improved, which is preferable.

[0110] Specific examples of organic compounds that can be used for the host material include 9,9′-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazine-2,4-diyl}bis(9H-carbazole) (abbreviation: SiTrzCz2) represented by structural formula (450) and 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz) represented by structural formula (451). 9-{4-phenyl-6-[3-(triphenylsilyl)phenyl]-1,3,5-triazin-2-yl}-9H-carbazole (abbreviation: SiCzTrz) represented by structural formula (452), 9-{4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazin-2-yl}-9H-carbazole (abbreviation: DSiCzTrz) represented by structural formula (453), 9-(biphenyl) represented by structural formula (454), 3-{6-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)biphenyl-4-yl]diphenylsilyl}phenyl)-9H-carbazole (abbreviation: CzSiTzn), 3-{6-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]dibenzothiophen-4-yl}-9-phenyl-9H-carbazole (abbreviation: m PCDBtPTzn), 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviation: PSiCzCz) represented by structural formula (456), and [4-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)phenyl]triphenylsilane (abbreviation: TDBA-Si) represented by structural formula (457). Organic compounds represented by structural formulas (458), (459), and (460) can also be used. The organic compounds represented by structural formulas (450) to (460) can be used, for example, as host materials for the light-emitting layer of a blue light-emitting device.

[0111]

[0112]

[0113] Specific examples of the organic compound that can be used for the host material include 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm) represented by structural formula (461), 4-(9′-phenyl-[3,3′-bi-9H-carbazol]-9-yl)benzofuro[3,2-d]pyrimidine (abbreviation: 4PCCzBfpm) represented by structural formula (462), and Examples include 9-(4,6-diphenylpyrimidin-2-yl)-9′-phenyl-2,3′-bi-9H-carbazole (abbreviation: 2PCCzPm) represented by structural formula (463) and 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9′-phenyl-3,3′-bi-9H-carbazole (abbreviation: mPCCzPTzn) represented by structural formula (464). The organic compounds represented by structural formulas (461) to (464) can be used, for example, as host materials for the light-emitting layer of a green light-emitting device.

[0114]

[0115] Specific examples of the organic compound that can be used for the host material include 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3′-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4′-(9-phenyl-9H-carbazol-3-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), and 2-[4′-(9-phenyl-9H-carbazol-3-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq). )-3,1′-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3′-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6- Bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-([2,2'-binaphthalen]-6-yl)-4-[3-(dibenzothiophene 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl) 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm) Examples of the compound include organic compounds having a heteroaromatic ring containing a diazine ring, such as 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz) and 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm).

[0116]

[0117]

[0118]

[0119] In this specification and the like, a "heteroaromatic ring containing ring A" includes a fused ring containing ring A and ring A itself. Ring A is a heteroaromatic ring. For example, in the case of a diazine ring, a "heteroaromatic ring containing a diazine ring" includes a fused ring containing the diazine ring and the diazine ring itself.

[0120] <Phosphorescent Material> A phosphorescent material refers to a compound that exhibits phosphorescence but does not exhibit fluorescence in a temperature range from a low temperature (e.g., 77 K) to room temperature (i.e., 77 K to 313 K). The phosphorescent material preferably contains a metal element with a large spin-orbit interaction, and examples thereof include an organometallic complex, a metal complex, and a rare earth metal complex. Specifically, a transition metal element is preferred, and a platinum group element (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt)) is particularly preferred. Among these, iridium is preferred because it can increase the transition probability involved in the direct transition between the singlet ground state and the triplet excited state.

[0121] Examples of phosphorescent materials that exhibit blue or green light and have an emission spectrum with a peak wavelength of 450 nm or more and 570 nm or less include the following materials.

[0122] For example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp) ３ ]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz) ３ ]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b) ３ ]), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPr5btz) ３]), organic iridium complexes having a 4H-triazole ring such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp) ３ ]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me) ３ ]), fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim) ３ ]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me) ３ organometallic complexes having an imidazole ring such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C2']iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr ６ ), bis[2-(4',6'-difluorophenyl)pyridinato-N,C2']iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C ２’} Iridium(III) picolinate (abbreviation: [Ir(CF ３ ppy) ２ (pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’]iridium(III) acetylacetonate (abbreviation: FIr(acac)), an organic iridium complex having a phenylpyridine derivative as a ligand having an electron-withdrawing group, such as (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-di (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC]phenoxy-κC}-9-[3,5-di(methyl-d)-4-phenyl-2-pyridinyl-κN]carbazole-2,1-diyl-κC)platinum(II) (abbreviation: Pt(mmtBubOcz35dm4ppy-d ６ )) and other organic platinum complexes.

[0123] Examples of phosphorescent materials that exhibit green or yellow color and have an emission spectrum with a peak wavelength of 495 nm or more and 590 nm or less include the following materials.

[0124] For example, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ３ ]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ３ ]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ２ (acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ２ (acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm) ２ (acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm) ２(acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp) ２ (acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) ２ organic iridium complexes having a pyrimidine ring such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me) ２ (acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr) ２ organic iridium complexes having a pyrazine ring, such as tris(2-phenylpyridinato-N,C(acac)]); ２’ ) Iridium(III) (abbreviation: [Ir(ppy) ３ ]), bis(2-phenylpyridinato-N,C ２’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy) ２ (acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq) ２ (acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq) ３ ]), tris(2-phenylquinolinato-N,C ２’ ) Iridium(III) (abbreviation: [Ir(pq) ３ ]), bis(2-phenylquinolinato-N,C ２’ ) iridium(III) acetylacetonate (abbreviation: [Ir(pq) ２ (acac)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-phenyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy) ２(4dppy)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC], [2-d3-methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviated as Ir(5mppy-d ３ ) ２ (mbfpypy-d ３ )), {2-(methyl-d ３ )-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofuro[2,3-b]pyridin-7-yl-κC}bis{5-(methyl-d ３ )-2-[5-(methyl-d ３ )-2-pyridinyl-κN]phenyl-κC}iridium(III) (abbreviation: Ir(5mtpy-d ６ ) ２ (mbfpypy-iPr-d ４ )), [2-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) ２ (mbfpypy-d3)), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) ２ organic iridium complexes having a pyridine ring, such as bis(2,4-diphenyl-1,3-oxazolato-N,C (mdppy)); ２’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(dpo) ２ (acac)]), bis{2-[4′-(perfluorophenyl)phenyl]pyridinato-N,C ２’} Iridium (III) acetylacetonate (abbreviation: [Ir(p-PF-ph) ２ (acac)]), bis(2-phenylbenzothiazolato-N,C ２’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(bt) ２In addition to organometallic complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)]), ３ rare earth metal complexes such as (2-{1-(5-tert-butylbiphenyl-2-yl)-4-[3-tert-butyl-5-(4-phenyl-2-pyridinyl-κN)phenyl-κC6]-2-benzimidazolyl-κN3}-4,6-di-tert-butylphenolato-κO)platinum(II) (abbreviation: Pt(tBudppymmtBubiz-tBubp) and organometallic platinum complexes such as [2-(4-(3,5-di-tert-butylphenyl)-6-{3-[4-(5′-tert-butyl[1,1′:3′,1″-terphenyl]-2′-yl)-2-pyridinyl-κN]phenyl-κC2}-2-pyridinyl-κN)phenolato-κO]platinum(II) (abbreviation: Pt(4tButppppypyp-mmtBup)). Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium atoms can also be used.

[0125] Examples of phosphorescent materials that exhibit yellow or red color and have an emission spectrum with a peak wavelength of 570 nm or more and 750 nm or less include the following materials.

[0126] For example, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm) ２ (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm) ２ (dpm)]), (dipivaloylmethanato)bis[4,6-di(naphthalen-1-yl)pyrimidinato]iridium(III) (abbreviation: [Ir(dpm)] ２ organometallic complexes having a pyrimidine ring such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr) ２ (acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [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-heptanedionato-κ ２ O,O')iridium(III) (abbreviation: [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-heptanedionato-κ ２ O,O′)iridium(III) (abbreviation: [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-heptanedionato-κO,O′)iridium(III) (abbreviation: [Ir(dmdppr-dmp) ２ (dpm)]), (acetylacetonato)bis(2-methyl-3-phenylquinoxalinato-N,C ２’ ) Iridium(III) (abbreviation: [Ir(mpq) ２ (acac)]), (acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C ２’ ) Iridium(III) (abbreviation: [Ir(dpq) ２ (acac)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) ２ organometallic complexes having a pyrazine ring, such as tris(1-phenylisoquinolinato-N,C(acac)]), ２’ ) Iridium(III) (abbreviation: [Ir(piq) ３ ]), bis(1-phenylisoquinolinato-N,C ２’ ) iridium(III) acetylacetonate (abbreviation: [Ir(piq) ２ (acac)]), and bis[4,6-dimethyl-2-(2-quinolinyl-κN)phenyl-κC] (2,4-pentanedionato-κ２ O,O')iridium(III) (abbreviation: [Ir(dmpqn) ２ (acac)]), platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum(II) (abbreviation: [PtOEP]), tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)]), ３ (Phen)]), and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA) ３ (Phen)]. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium atoms can also be used.

[0127] <<Specific Example of Fluorescent Material>> The luminescent material 134 is a material having a function of converting singlet excitation energy into luminescence. When a fluorescent material other than a TADF material is used as the material having a function of converting singlet excitation energy into luminescence, the fluorescent material is preferably a compound having, as part of its structure, a luminophore and a protecting group having a function of increasing the distance between the luminophore and another energy donor.

[0128] Here, the term "luminophore" refers to an atomic group (skeleton) that causes light emission in a fluorescent material. The luminophore generally has a π bond and preferably contains an aromatic ring, preferably a fused aromatic ring or a fused heteroaromatic ring. In another embodiment, the luminophore can be considered as an atomic group (skeleton) containing an aromatic ring whose transition dipole vector exists on the ring plane. In addition, when one fluorescent material has multiple fused aromatic rings or fused heteroaromatic rings, the lowest S １ In some cases, a skeleton having a level is considered to be the luminophore of the fluorescent material. In other cases, a skeleton having an absorption edge at the longest wavelength among the plurality of fused aromatic rings or fused heteroaromatic rings is considered to be the luminophore of the fluorescent material. In other cases, the luminophore of the fluorescent material can be predicted from the shape of the emission spectrum of each of the plurality of fused aromatic rings or fused heteroaromatic rings.

[0129] Examples of such luminophores include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, a naphthobisbenzofuran skeleton, etc. In particular, fluorescent materials having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because of their high fluorescence quantum yield.

[0130] The substituent used as a protecting group is a T group possessed by the luminophore and the host material. １ The triplet excitation energy level must be higher than the triplet excitation energy level. Therefore, it is preferable to use a saturated hydrocarbon group. This is because a substituent without a π bond has a high triplet excitation energy level. Furthermore, a substituent without a π bond has a low ability to transport carriers (electrons or holes). Therefore, a saturated hydrocarbon group can increase the distance between the luminophore and the host material without substantially affecting the excited state or carrier transport property of the host material. Furthermore, in organic compounds having both a substituent without a π bond and a substituent having a π-conjugated system, frontier orbitals (HOMO (Highest Occupied Molecular Orbital, also referred to as the highest occupied molecular orbital) and LUMO (Lowest Unoccupied Molecular Orbital, also referred to as the lowest unoccupied molecular orbital))) are often present on the side of the substituent having the π-conjugated system, and in particular, the luminophore often has a frontier orbital. As will be described later, the overlap of the HOMO and LUMO of the energy donor and energy acceptor is important for the energy transfer via the Dexter mechanism. Therefore, by using a saturated hydrocarbon group as a protecting group, the distance between the frontier orbital of the host material, which is the energy donor, and the frontier orbital of the guest material, which is the energy acceptor, can be increased, thereby suppressing the energy transfer via the Dexter mechanism.

[0131] Specific examples of the protecting group include alkyl groups having 1 to 10 carbon atoms. Furthermore, since the protecting group is required to increase the distance between the luminophore and the host material, bulky substituents are preferred. Therefore, alkyl groups having 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, and trialkylsilyl groups having 3 to 10 carbon atoms are preferably used. Bulky branched-chain alkyl groups are particularly preferred as alkyl groups. Furthermore, the substituents are particularly preferred when they have a quaternary carbon, as they become bulky substituents. Furthermore, alkyl groups having an aryl group, such as a cumyl group, are preferably used.

[0132] As described above, it is more preferable that the protecting group is deuterated. When the protecting group has deuterium, specific examples of the protecting group that can be suitably used include a deuterium-containing alkyl group having 3 to 10 carbon atoms, a deuterium-containing substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a deuterium-containing trialkylsilyl group having 3 to 10 carbon atoms.

[0133] Furthermore, it is preferable to have five or more protecting groups per luminophore. This configuration allows the entire luminophore to be covered with the protecting groups, thereby making it possible to appropriately adjust the distance between the host material and the luminophore. It is more preferable that the protecting groups are not directly bonded to the luminophore. For example, the protecting groups may be bonded to the luminophore via a divalent or higher substituent such as an arylene group or an amino group. By bonding the protecting groups to the luminophore via the substituent, the distance between the luminophore and the host material can be effectively increased. Therefore, when the luminophore and the protecting groups are not directly bonded, having four or more protecting groups per luminophore can effectively suppress energy transfer via the Dexter mechanism.

[0134] Specific examples of fluorescent substances having a luminophore and a protecting group having the function of increasing the distance between the luminophore and another energy donor include N,N'-(2-phenylanthracene-9,10-diyl)-N,N,N',N'-tetrakis(3,5-di-tert-butylphenyl)diamine (abbreviation: 2Ph-mmtBuDPhA2Anth), 2,2',6,6'-tetrakis(3,5-di-tert-butylphenyl)-N,N,N',N'-tetrakis(3,5-di-tert-butylphenyl)-[9,9'-bianthracene]-10,10'-diamine (abbreviation: 22'66'mmtBuPh-mmtBuDPhA2BANT), N,N'-bis{3,5-bis(1-adamantyl)phenyl}-N,N'-bis(3,5-di-t N,N'-bis(3,5-di-tert-butylphenyl)-N,N'-bis{3,5-bis[4-(1-adamantyl)phenyl]phenyl}-2,6-diphenylanthracene-9,10-diamine (abbreviation: 2Ph-mmAdtBuDPhA2Anth-03), N,N'-bis(3,5-di-tert-butylphenyl)-N,N'-bis{3,5-bis[4-(1-adamantyl)phenyl]phenyl}-2,6-diphenylanthracene-9,10-diamine (abbreviation: 2,6P h-mmAdPtBuDPhA2Anth), N,N'-bis(3,5-di-tert-butylphenyl)-N,N'-bis{3,5-bis[4-(1-adamantyl)phenyl]phenyl}-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmAdPtBuDPhA2Anth), N,N'-bis{3,5-bis(tricyclo[5.2.1.0 ２，６]decan-8-yl)phenyl}-N,N'-bis(3,5-di-tert-butylphenyl)-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmTCDtBuDPhA2Anth), N,N'-bis{3,5-bis(2-bicyclo[2.2.1]heptyl)phenyl}-N,N'-bis(3,5-di-tert-butylphenyl)-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmnbtBuDPhA2Anth), N,N'-bis[3,5-bis(2-adamantyl)phenyl] N,N'-bis[3,5-bis(3,5-di-tert-butylphenyl)phenyl]-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmAdtBuDPhA2Anth-02), N,N'-bis[3,5-bis(2-adamantyl)phenyl]-N,N'-bis(3,5-di-tert-butylphenyl)-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmAdtBuDPhA2Anth), N,N'-(2-trimethylsilylanthracene-9,10-diyl)- N,N,N',N'-tetrakis(3,5-di-tert-butylphenyl)diamine (abbreviation: 2TMS-mmtBuDPhA2Anth), N,N'-(pyrene-1,6-diyl)bis[N-(2-methylphenyl)-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine] (abbreviation: 1,6oMechBnfAPrn), N,N'-(pyrene-1,6-diyl)bis(N-phenyl-6-trimethylsilylbenzo[b]naphtho[1,2-d]furan-8-amine) (abbreviation: 1,6TMSBnfAP rn), N,N'-(3,8-dicyclohexylpyrene-1,6-diyl)bis[N-phenyl-(6-cyclohexylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: ch-1,6chBnfAPrn), and N,N'-bis[9-(3,5-di-tert-butylphenyl)-9H-carbazol-2-yl]-N,N'-diphenyl-naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10mmtBuPCA2Nbf(IV)-02). Materials in which the protecting groups of these compounds have been deuterated can also be used.

[0135]

[0136]

[0137]

[0138] Furthermore, the fluorescent materials are not limited to those mentioned above, and any of the fluorescent materials listed in Embodiment Mode 2 can be used.

[0139] <<Specific Examples of TADF Materials>> TADF materials preferably include, for example, organic compounds having a nitrogen-containing fused heteroaromatic ring, and more preferably organic compounds having a diaza-boranaphtho-anthracene ring or an indolo-carbazole ring. The nitrogen-containing fused aromatic ring preferably includes, in addition to boron and the above ring, at least one of an aromatic ring (monocyclic aromatic ring or polycyclic aromatic ring) and an alkyl group. Examples of the aromatic ring include a benzene ring, a fluorene ring, a carbazole ring, and a dibenzofuran ring. Examples of the alkyl group include a methyl group, an ethyl group, a cyclohexyl group, a propyl group, and a tert-butyl group. A structure in which an alkyl group is bonded to an aromatic ring is preferred, and a structure in which multiple alkyl groups are bonded to one benzene ring is particularly suitable. A structure in which multiple alkyl groups are bonded to one benzene ring constituting a fused ring (such as a carbazole ring, a fluorene ring, or a dibenzofuran ring) is also desirable. The inclusion of a structure in which an alkyl group is bonded to an aromatic ring makes it possible to suppress concentration quenching and to suppress aggregation or crystallization due to stacking interactions between molecules, thereby improving device characteristics (efficiency, reliability, etc.). Note that the above examples of aromatic rings and alkyl groups are preferred examples, and other aromatic rings and alkyl groups described in this specification can also be used.

[0140] Specific examples of organic compounds having a condensed heteroaromatic ring containing nitrogen include 5,9-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: DABNA-1) represented by structural formula (400), 2,12-di-tert-butyl-5,9-bis(4-tert-butylphenyl)-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene (abbreviation: t-DABNA) represented by structural formula (401), and 2,12-di-tert-butyl-5,9-bis(4-tert-butylphenyl)-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene (abbreviation: t-DABNA) represented by structural formula (402). -di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: MetBu4DABNA), 7-(9H-carbazol-9-yl)-5,9-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: Cz-DABNA) represented by structural formula (403), N,N,5,9-tetraphenyl-5H,9H-[1,4 ]benzazaborino[2,3,4-kl]phenazaborin-7-amine (abbreviation: DPhA-DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-7-amine (abbreviation: DPhA-tBu4DABNA) represented by structural formula (405), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl) represented by structural formula (406), 2,12-di-tert-butyl-5,9-bis(4-(tert-butyl)phenyl)-7-(3,6-di-tert-butyl-9H-carbazol-9-yl)-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene (abbreviation: TBN-TPA) represented by structural formula (407), N represented by structural formula (408), ７ , N ７ , N １３ , N １３,5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborino[2,3,4-kl][1,4]benzazaborino[4',3',2':4,5][1,4]benzazaborino[3,2-b]phenazaborine-7,13-diamine (abbreviation: ν-DABNA), N represented by structural formula (409) ７ , N ７ , N １３ , N １３,5,15-hexaphenyl-9,11-bis[4-(tert-butyl)phenyl]-5,9,11,15-tetrahydro-5,9,11,15-tetraaza-19b,20b-diborazinaphtho[3,2,1-de:1',2',3'-jk]pentacene-7,13-diamine (abbreviation: t-Bu-ν-DABNA), 3,11-bis(2,7-di-tert-butyl-9H-carbazol-9-yl)-7-[2,7-di(3,5-di-tert-butyl)phenyl]-5,9,11,15-tetrahydro-5,9,11,15-tetraaza-19b,20b-diborazinaphtho[3,2,1-de:1',2',3'-jk]pentacene-7,13-diamine (abbreviation: t-Bu-ν-DABNA) represented by structural formula (410), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: mmtBuP2Cz-(2,7tBuCz)2DABNA), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine-3-amine (abbreviation: DABNA-2) represented by structural formula (411), N-( [1,1'-biphenyl]-3-yl)-N,5,9-tris(2,6-dimethylphenyl)-3,11-diphenyl-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracen-7-amine (abbreviation: mBP-DABNA-Me), N-([1,1'-biphenyl]-4-yl)-N,5,9-tris(2,6-dimethylphenyl)-2,12-diphenyl-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracen-7-amine represented by structural formula (413) [3,2,1-de]anthracene-7-amine (abbreviation: pBP-DABNA-Me), 2-(4-tert-butylphenyl)benz[5,6]indolo[3,2,1-jk]benzo[b]carbazole (abbreviation: tBuPBibc) represented by structural formula (414), benz[5,6]indolo[3,2,1-jk]benzo[b]carbazole (abbreviation: Bibc) represented by structural formula (415), and compounds represented by structural formulas (416) to (421) can be preferably used.

[0141]

[0142]

[0143]

[0144] As the TADF material, fullerene and its derivatives, acridine and its derivatives, eosin derivatives, etc. can be used. Metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. can also be used. Examples of the metal-containing porphyrin include protoporphyrin-tin fluoride complex (SnF) represented by structural formula (422). ２ (Proto IX)), mesoporphyrin-tin fluoride complex (SnF) represented by structural formula (423) ２ (Meso IX)), hematoporphyrin-tin fluoride complex (SnF) represented by structural formula (424) ２ (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF) represented by structural formula (425) ２ (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF) represented by structural formula (426) ２ (OEP)), etioporphyrin-tin fluoride complex (SnF) represented by structural formula (427), ２ (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl) represented by structural formula (428) ２ OEP) and the like.

[0145]

[0146] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ) represented by structural formula (429), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9′-phenyl-9H,9′H-3,3′-bicarbazole (abbreviation: PCC) represented by structural formula (430), zTzn), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9′-phenyl-3,3′-bi-9H-carbazole (abbreviation: PCCzPTzn) represented by structural formula (431), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ) represented by structural formula (432), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT) represented by structural formula (433), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN) represented by structural formula (434), bis[4-( Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring can also be used, such as 9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS) and 10-phenyl-10H,10′H-spiro[acridine-9,9′-anthracene]-10′-one (abbreviation: ACRSA) represented by structural formula (436). Because these heterocyclic compounds have one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, they have high electron transport properties and hole transport properties, making them preferable. Among the π-electron-deficient heteroaromatic rings, pyridine rings, diazine rings (pyrimidine rings, pyrazine rings, pyridazine rings), and triazine rings are preferred due to their stability and reliability. In particular, benzofuropyrimidine rings, benzothienopyrimidine rings, benzofuropyrazine rings, and benzothienopyrazine rings have high acceptor properties and good reliability, and therefore it is preferable to use a compound having at least one of these rings or a fused ring containing at least one of these rings.Among π-electron-rich heteroaromatic rings, acridine rings, phenoxazine rings, phenothiazine rings, furan rings, thiophene rings, and pyrrole rings are stable and reliable, so it is preferable to use a compound having at least one of these rings or a fused ring containing at least one of these rings. As a fused ring containing a furan ring, a dibenzofuran ring is preferable, and as a fused ring containing a thiophene ring, a dibenzothiophene ring is preferable. As a fused ring containing a pyrrole ring, an indole ring, a carbazole ring, an indolocarbazole ring, a bicarbazole ring, or a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole ring is particularly preferable. In addition, a compound in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded has both strong electron-donating properties of the π-electron-rich heteroaromatic ring and strong electron-accepting properties of the π-electron-deficient heteroaromatic ring, and is therefore S. １ Level and T １ This is particularly preferred because the energy difference between the levels is small, allowing thermally activated delayed fluorescence to be obtained efficiently. Instead of the π-electron-deficient heteroaromatic ring, an aromatic ring bonded to an electron-withdrawing group such as a cyano group may be used. Furthermore, a triarylamine skeleton, a phenazine skeleton, or the like can be used as the π-electron-rich skeleton. Furthermore, boron-containing skeletons such as a xanthene ring, a thioxanthene dioxide ring, an oxadiazole ring, a triazole ring, an imidazole ring, an anthraquinone ring, phenylborane, or boranthrene, an aromatic ring bonded to a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, or a sulfone skeleton can be used as the π-electron-deficient skeleton. In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used in place of at least one of the π-electron-deficient heteroaromatic ring and the π-electron-rich heteroaromatic ring.

[0147]

[0148] Alternatively, a TADF material in which the singlet excited state and the triplet excited state are in thermal equilibrium may be used. Such a TADF material has a shorter emission lifetime (excitation lifetime), which can suppress a decrease in efficiency in the high-brightness region of a light-emitting device. Specifically, an organic compound represented by structural formula (437) can be used. Another example of a TADF material is 3,6-bis(diphenylamino)-9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9H-carbazole (abbreviation: DACT-II), represented by structural formula (438).

[0149]

[0150] By using the TADF material as the light-emitting material 133 or 134, a light-emitting device with high luminous efficiency can be provided.

[0151] 1A illustrates a structure in which the first light-emitting unit 501 includes a first hole-transport layer 112_1, a hole-injection layer 111, and a first electron-transport layer 114_1 in addition to the first light-emitting layer 113_1, and a structure in which the second light-emitting unit 502 includes a second hole-transport layer 112_2, a second electron-transport layer 114_2, and an electron-injection layer 115 in addition to the second light-emitting layer 113_2. However, the structure of the organic compound layer 103 according to one embodiment of the present invention is not limited thereto, and any of the layers may not be provided, or other layers may be provided.

[0152] 1A, the first hole transport layer 112_1 and the second hole transport layer 112_2 are illustrated as single layers, but the first hole transport layer 112_1 and the second hole transport layer 112_2 may have a single layer or a stacked structure. Furthermore, the first hole transport layer 112_1 and the second hole transport layer 112_2 do not necessarily have to have the same structure. For example, the first hole transport layer 112_1 may be a single layer, and the second hole transport layer 112_2 may have a stacked structure.

[0153] In one embodiment of the present invention, the first hole-transport layer 112_1 and the second hole-transport layer 112_2 each contain a light-emitting substance having excellent hole-transport properties, poor electron-transport properties, and higher T than the light-emitting substance 134 used in the light-emitting layer. １ It is more preferable to use a material with a high level, which has a higher T than the light-emitting material 133 used in the light-emitting layer. １ It is more preferable to use a material having a high level. In particular, a layer of the first hole transport layer 112_1 in contact with the first light-emitting layer 113_1 is preferably made of a material having a higher T than the light-emitting material 134 used in the first light-emitting layer 113_1. １ A material having a high level is used for the hole transport layer in contact with the second light-emitting layer 113_2 of the second hole transport layer 112_2, and a material having a high level is used for the hole transport layer in contact with the second light-emitting layer 113_2. １ It is preferable to use a material having a high level, and a layer of the first hole transport layer 112_1 in contact with the first light emitting layer 113_1 is made of a material having a higher T than the light emitting material 133 used in the first light emitting layer 113_1. １ A material having a high level is used, and a layer of the second hole transport layer 112_2 that is in contact with the second light-emitting layer 113_2 is provided with a material having a higher T than the light-emitting material 133 used in the light-emitting layer. １ It is more preferable to use a material with a high level. This can prevent the excitation energy of excitons generated by the recombination of carriers in the light-emitting layer from diffusing to a layer adjacent to the light-emitting layer, resulting in a light-emitting device with high light-emitting efficiency. An organic compound having a π-electron-rich heteroaromatic ring such as a carbazole ring and not having a triarylamine skeleton has excellent hole transport properties and can be used as a material for a light-emitting device with high light-emitting efficiency. １ Many of these organic compounds have high levels and are suitable for the first hole-transporting layer 112_1 and the second hole-transporting layer 112_2.

[0154] Furthermore, by forming the first hole-transport layer 112_1 as a stacked layer and using a material having a LUMO level higher than that of a material constituting the light-emitting layer for a layer in contact with the first light-emitting layer 113_1, it is possible to prevent electrons from passing through from the first light-emitting layer 113_1 to the first electrode 101. Similarly, by forming the second hole-transport layer 112_2 as a stacked layer and using a material having a LUMO level higher than that of a material constituting the light-emitting layer for a layer in contact with the second light-emitting layer 113_2, it is possible to prevent electrons from passing through from the second light-emitting layer 113_2 to the intermediate layer 160, and therefore a highly efficient and long-life display device can be manufactured.

[0155] Specific examples of organic compounds that can be used for the layer in contact with the light-emitting layer in the first hole-transporting layer 112_1 and the second hole-transporting layer 112_2 include 9-[3-(triphenylsilyl)phenyl]-3,9′-bi-9H-carbazole (abbreviation: PSiCzCz) represented by structural formula (350), 9′-[3-(triphenylsilyl)phenyl]-9′H-9,3′:6′,9″-terecarbazole (abbreviation: PSiCzGI) represented by structural formula (351), and 9,9″-(1,3-phenylene)bis(3,9′-bi-9H-carbazole) represented by structural formula (352). 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP) represented by structural formula (353), 9,9″-[3,3′-(diphenylsilyl)diphenyl]bis(3,9′-bi-9H-carbazole) (abbreviation: mCzCz2PSi) represented by structural formula (354), 3,3′-9H-carbazol-9-yl-biphenyl (abbreviation: mCBP) represented by structural formula (359), 9′-phenyl-9′H-9,3′:6′,9″-tercarbazole (abbreviation: PhCzGI) represented by structural formula (360), 12-[3 -(9H-carbazol-9-yl)phenyl]-5,12-dihydro-5-phenyl-indolo[3,2-a]carbazole (abbreviation: mCzPICz), 5,12-bis[3-(9H-carbazol-9-yl)phenyl]-5,12-dihydro-indolo[3,2-a]carbazole (abbreviation: mCzP2ICz) represented by structural formula (362), 5-[3-(9H-carbazol-9-yl)phenyl]-5,12-dihydro-12-phenyl-indolo[3,2-a]carbazole (abbreviation: mCzPICz-02) represented by structural formula (363), Examples include 12,12′-(1,4-phenylene)bis(5,12-dihydro-5-phenyl-indolo[3,2-a]carbazole) (abbreviation: ICz2P) represented by structural formula (364), 12,12′-(1,3-phenylene)bis(5,12-dihydro-5-phenyl-indolo[3,2-a]carbazole) (abbreviation: mICz2P) represented by structural formula (365), and 5,5′-(1,3-phenylene)bis(5,12-dihydro-12-phenyl-indolo[3,2-a]carbazole) (abbreviation: mICz2P-02) represented by structural formula (366).Further, organic compounds represented by structural formulas (355) to (358) can be used. When the organic compounds represented by structural formulas (350) to (366) are used in a blue light-emitting device, for example, they can be used for the first hole-transport layer 112_1 and the second hole-transport layer 112_2, which are in contact with the light-emitting layer. Further, the organic compounds represented by structural formulas (350) to (366) can also be used as host materials for the light-emitting layer of a blue light-emitting device, for example.

[0156]

[0157]

[0158] Specific examples of organic compounds that can be used for the layer in contact with the light-emitting layer in the first hole-transporting layer 112_1 and the second hole-transporting layer 112_2 include 3,3′-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP) represented by structural formula (367), 9-(2-naphthyl)-9′-phenyl-3,3′-bi-9H-carbazole (abbreviation: βNCCP) represented by structural formula (368), and 9-(biphenyl-3-yl)-9′-(biphenyl-4-yl)-9H,9′H-3,3′-bicarbazole (abbreviation: mBPCCBP) represented by structural formula (369). ), 9-(biphenyl-4-yl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: PCCzBP) represented by structural formula (370), 9-phenyl-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp) represented by structural formula (371), 3,9-bis(9-phenyl-9H-carbazol-3-yl)-9H-carbazole (abbreviation: PCCzPC) represented by structural formula (372), PCCzPC-02 represented by structural formula (373), 9,9'-bis(biphenyl-4-yl) represented by structural formula (374), )-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9-[(4-phenyl)dibenzothiophen-2-yl]-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: PDBtCPC) represented by structural formula (375), 5,9-bis(biphenyl-3-yl)-7,9-dihydro-7,7-dimethyl-5H-cyclopenta[1,2-b:4,3-b']dicarbazole (abbreviation: mBPCdcz) represented by structural formula (377), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: PDBtCPC) represented by structural formula (378), carbazole (abbreviation: βNCCBP), 9-(9,9-dimethyl-9H-fluoren-2-yl)-9′-phenyl-3,3′-bi-9H-carbazole (abbreviation: PCCzF) represented by structural formula (378), 9,9′-di-2-naphthyl-3,3′-9H,9′H-bicarbazole (abbreviation: BisβNCz) represented by structural formula (379), 9-(biphenyl-3-yl)-9′-phenyl-3,3′-bi(9H-carbazole) (abbreviation: PCCzmBP) represented by structural formula (380), and BisDBtCz represented by structural formula (381) can also be mentioned.The organic compounds represented by Structural Formulas (367) to (381) can be used, for example, for the first hole-transport layer 112_1 and the second hole-transport layer 112_2 of a green light-emitting device, which are in contact with the light-emitting layer. The organic compounds represented by Structural Formulas (367) to (381) can also be used, for example, as a host material for the light-emitting layer of a green light-emitting device.

[0159]

[0160]

[0161]

[0162] In addition, it is preferable to use an organic compound having a triarylamine skeleton for the layer not in contact with the light-emitting layer out of the first hole-transport layer 112_1 and the second hole-transport layer 112_2. Examples of aromatic rings contained in organic compounds having a triarylamine skeleton include monocyclic aromatic rings and polycyclic aromatic rings, and polycyclic aromatic rings are particularly preferred because they have high heat resistance and stability. Furthermore, organic compounds having a triarylamine skeleton and a fluorene ring are preferred because they have good reliability, high hole-transport properties, and reduced power consumption. Furthermore, these aromatic rings may have an alkyl group as a substituent.

[0163] Examples of the monocyclic aromatic ring include aromatic hydrocarbon rings such as a benzene ring, and heteroaromatic rings such as a pyrrole ring and a furan ring. The presence of an aromatic ring as a substituent improves heat resistance, specifically, the glass transition temperature (T ｇ In addition, by having an aromatic ring as a substituent, it is possible to adjust the transportability of carriers such as holes or electrons. In addition, by having a plurality of these monocyclic aromatic rings, it is possible to further improve T ｇIt is possible to improve the refractive index, and it is preferable that the compound has a biphenyl structure or a terphenyl structure, for example. The compound may have a paraphenylene structure, a metaphenylene structure, or an orthophenylene structure. By having at least one of a metaphenylene structure or an orthophenylene structure, the solubility of the compound can be improved, the production can be facilitated, and the refractive index can also be reduced. Furthermore, in the case of a compound having three or more benzene rings, such as a terphenyl structure, it is preferable to have an aromatic ring containing at least two of a paraphenylene structure, a metaphenylene structure, and an orthophenylene structure, because this allows adjustment of the solubility and refractive index as well as the carrier transport property.

[0164] Examples of polycyclic aromatic rings include aromatic hydrocarbon rings such as naphthalene ring, phenanthrene ring, chrysene ring, triphenylene ring, fluorene ring, and spirobifluorene ring, as well as heteroaromatic rings such as carbazole ring, dibenzofuran ring, dibenzothiophene ring, and xanthene ring. Compounds having a polycyclic aromatic ring as a substituent are preferred because they can improve heat resistance compared to compounds having a monocyclic aromatic ring. It is also preferred to have multiple of these polycyclic aromatic rings. When multiple polycyclic aromatic rings are present, they may be the same or different. When the same ring is present, examples include a structure having multiple aromatic hydrocarbon rings, a structure having multiple heteroaromatic rings, and a structure having one or more aromatic hydrocarbon rings and one or more heteroaromatic rings. When the same aromatic ring is used, reduction in raw material costs and simplification of the synthesis process can be expected. When different aromatic rings are used, the transportability of carriers such as holes or electrons can be adjusted depending on the type of aromatic ring used, or T ｇ Examples of the structure having a plurality of polycyclic aromatic rings include a structure having a carbazole ring and a dibenzofuran ring, a structure having two, three, or four or more carbazole rings, and a structure having two, three, or four or more fluorene rings.

[0165] Furthermore, in the case of a compound having, as a substituent, a ring in which an aromatic ring (such as the monocyclic aromatic ring described above) is further fused to the polycyclic aromatic ring, the heat resistance can be further improved. Examples of the ring in which an aromatic ring is further fused to the polycyclic aromatic ring include a benzofluorene ring, a benzonaphthofuran ring, a benzoxanthene ring, and a benzonaphthothiophene ring.

[0166] In addition, the above-mentioned monocyclic aromatic ring and the above-mentioned polycyclic aromatic ring can be used as a substituent. Examples include a structure in which a monocyclic aromatic ring is used as a linking group between the nitrogen of the amine skeleton and the polycyclic aromatic ring. For example, a structure in which a phenylene group is used between the nitrogen and the fluorene ring, a structure in which a phenylene group is used between the nitrogen and the carbazole ring, or a structure in which a phenylene group is used between the nitrogen and the dibenzofluorene ring. In addition, a structure in which multiple polycyclic aromatic rings are bonded to one phenylene group used as a linking group is also effective. The multiple polycyclic aromatic rings may be the same aromatic ring or different aromatic rings. For example, a compound in which both a carbazole ring and a dibenzofluorene ring are bonded to one phenylene group is T ｇ The functionalities of both the carbazole ring and the dibenzofluorene ring can be obtained while improving the functionalities of both the carbazole ring and the dibenzofluorene ring.

[0167] Examples of alkyl groups include methyl, ethyl, propyl, tertiary butyl, cyclohexyl, and adamantyl groups. A layer using a compound having an alkyl group as a substituent can lower the refractive index. Therefore, total reflection at the interface between the layer and other layers can be reduced, improving light extraction efficiency. Furthermore, using a compound having these substituents in the hole transport layer can also reduce the refractive index. In particular, using a compound having a triarylamine skeleton and an alkyl group in the hole transport layer can synergistically enhance the effect of improving light extraction efficiency. Furthermore, the effect can be enhanced when the alkyl group has multiple carbon atoms, preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. Furthermore, it is preferable that multiple alkyl groups are bonded to one aromatic ring, as this can further reduce the refractive index. In this case, the multiple alkyl groups may be the same or different. For example, two or three tertiary butyl groups may be bonded to one benzene ring. Furthermore, when multiple aromatic rings are present, bonding alkyl groups to two or more aromatic rings can reduce the refractive index. Furthermore, the refractive index can be adjusted by including alkyl groups on some of the multiple aromatic rings. For example, when there are three aromatic rings, there may be a structure in which two of the aromatic rings have alkyl groups and the remaining aromatic ring does not have an alkyl group.

[0168] Specific examples of organic compounds containing a triarylamine skeleton are shown as the following structural formulas (300) to (330). In particular, BBASF (4) shown in structural formula (300), oBBASF shown in structural formula (301), BBAFLP (4) shown in structural formula (302), oFBiSF (2) shown in structural formula (303), FBiSF (4) shown in structural formula (304), oFBiSF shown in structural formula (305), FBimFLP shown in structural formula (306), and FBimMemFL shown in structural formula (307). P, SF(4)FAF represented by structural formula (308), FrBBiFLP represented by structural formula (309), tBu-oFBiSF(2) represented by structural formula (310), FBiFLPB represented by structural formula (311), DBfBBFLP(2) represented by structural formula (312), FLP2oBP represented by structural formula (313), PCAFLP(2)-02 represented by structural formula (314), tBu2FoFBi shown in structural formula (316), oFrTPPnox shown in structural formula (317), mPDBfBNBN shown in structural formula (317), BBAaBnf shown in structural formula (318) (7), DBfBB1TP shown in structural formula (319), BOx3Am shown in structural formula (320), BBA2BP shown in structural formula (321), PCBBi1BP shown in structural formula (322), structural formula (323) YGBBiBP-02 represented by the structural formula (324), YGBBiBP represented by the structural formula (324), PCBBiTP represented by the structural formula (325), YGBBiPDBf represented by the structural formula (326), BPPCA represented by the structural formula (327), PCBBiF represented by the structural formula (328), DBf-YGBBiBP represented by the structural formula (329), and YGTPDBfB represented by the structural formula (330) are preferred.

[0169]

[0170]

[0171]

[0172]

[0173] For example, for the first hole-transport layer 112_1 and the second hole-transport layer 112_2, among the organic compounds represented by Structural Formulas (300) to (330), an organic compound having an amine skeleton and a polycyclic heteroaromatic ring is preferably used, and an organic compound having an amine skeleton and a furan ring or a dibenzofuran ring is preferably used. In particular, when the first hole-transport layer 112_1 and the second hole-transport layer 112_2 have a stacked structure, an organic compound having a higher LUMO level than a material constituting the light-emitting layer (at least a host material, preferably a material constituting the light-emitting layer) is appropriately selected and used for the layer in contact with the light-emitting layer.

[0174] 1A illustrates the first electron-transport layer 114_1 and the second electron-transport layer 114_2 as single layers, the first electron-transport layer 114_1 and the second electron-transport layer 114_2 may have a single layer structure or a stacked structure. In addition, the first electron-transport layer 114_1 and the second electron-transport layer 114_2 do not necessarily have the same structure.

[0175] For example, the first electron-transporting layer 114_1 may be a single layer, and the second electron-transporting layer 114_2 may be a stacked layer. Specifically, the electron-transporting layer included in the cathode-side light-emitting unit (e.g., the second electron-transporting layer 114_2 in FIG. 1A ) may have a stacked layer structure, and the electron-transporting layer included in the other light-emitting unit (e.g., the first electron-transporting layer 114_1 in FIG. 1A ) may have a single layer structure.

[0176] In one embodiment of the present invention, the electron-transporting layer included in the cathode-side light-emitting unit may include at least one layer of an organic compound having a triazine ring. Alternatively, the electron-transporting layer may have a stacked structure using organic compounds having different triazine rings. In particular, the cathode-side layer of the stacked layers preferably includes an organic compound having a triazine ring and an alkali metal such as Li. This structure can improve electron injection properties.

[0177] The electron transport layer included in the light-emitting unit located closer to the anode than the light-emitting unit located on the cathode side (hereinafter also referred to as the anode-side light-emitting unit) may use the same organic compound as that used in the electron transport layer included in the cathode-side light-emitting unit, or a different organic compound. For example, an organic compound having a triazine ring, a pyrimidine ring, an imidazole ring, or an anthracene ring may be used. Furthermore, for example, an organic compound having a triazine ring different from the organic compound having a triazine ring used in the electron transport layer included in the cathode-side light-emitting unit may be used.

[0178] In order to reduce power consumption, it is preferable that the electron transport layer included in the light-emitting unit on the anode side also contains an organic compound having a triazine ring. In particular, using the same organic compound as that of the electron transport layer included in the light-emitting unit on the cathode side is preferable because it prevents the manufacturing equipment from becoming complicated and is advantageous in terms of raw material procurement costs.

[0179] Furthermore, the electron transport layer included in the light-emitting unit on the anode side contains an organic compound that does not contain a triazine ring, which makes it easier to control the carrier transport property and makes it possible to provide a light-emitting device with better characteristics. As the organic compound that does not contain a triazine ring, an organic compound that has a heteroaromatic ring containing a pyridine ring or an organic compound that has a heteroaromatic ring containing a diazine (pyrimidine or pyrazine) ring is preferred.

[0180] The electron transport layer included in the light-emitting unit on the anode side may have either a laminated structure or a single-layer structure, but the laminated structure provides high current efficiency, lower power consumption, and a light-emitting device with excellent characteristics. A single-layer structure is advantageous in terms of manufacturing costs because fewer film-forming chambers are required.

[0181] The organic compound having a triazine ring that can be used in the electron transport layer included in the light-emitting unit on the anode side and the electron transport layer included in the light-emitting unit on the cathode side has an electron mobility of 1×10 at a square root of an electric field strength [V / cm] of 600 or less. −７ cm ２ / Vs or more, preferably 1×10 −６ cm ２It is preferable that the material has an electron mobility of 1 / Vs or more. Note that other materials can be used as long as they have a higher electron transporting property than holes.

[0182] The organic compound having a triazine ring is preferably a compound containing a triazine ring and an aromatic ring. The aromatic ring may be a monocyclic aromatic ring, a polycyclic aromatic ring, an aromatic ring having an alkyl group as a substituent, an aromatic ring having a fluoro group as a substituent, or an aromatic ring containing a cyano group as a substituent. The triazine ring may have a substituent other than the aromatic ring, and the aromatic ring may have a substituent other than the fluoro group, cyano group, or alkyl group.

[0183] Examples of the monocyclic aromatic ring include aromatic hydrocarbon rings such as a benzene ring, and heteroaromatic rings such as a pyrrole ring, a pyridine ring, a pyrimidine ring, and a triazine ring. Having an aromatic ring as a substituent improves heat resistance, specifically, T ｇ and the electron transport property.

[0184] Examples of polycyclic aromatic rings include aromatic hydrocarbon rings such as naphthalene rings, phenanthrene rings, chrysene rings, triphenylene rings, fluorene rings, and spirobifluorene rings, as well as heteroaromatic rings such as carbazole rings, dibenzofuran rings, dibenzothiophene rings, xanthene rings, indolocarbazole rings, and indenocarbazole rings. Compounds having polycyclic aromatic rings as substituents are preferred because they can improve heat resistance compared to compounds having benzene rings. Furthermore, compounds having a ring in which an aromatic ring (such as a benzene ring, a naphthalene ring, or a pyridine ring) is fused to these polycyclic aromatic rings as a substituent can further improve heat resistance. Examples of rings in which an aromatic ring is fused to a polycyclic aromatic ring include a benzofluorene ring, a benzonaphthofuran ring, a benzoxanthene ring, and a benzonaphthothiophene ring. By providing a layer containing a highly heat-resistant compound near the cathode, damage to the device due to heat can be suppressed when high-temperature treatment such as a patterning step is performed after the layer or the cathode is formed.

[0185] Examples of alkyl groups include methyl, ethyl, propyl, tertiary butyl, cyclohexyl, and adamantyl groups. A layer using a compound having an alkyl group as a substituent can lower the refractive index. Therefore, total reflection at the interface between the layer and other layers can be reduced, improving light extraction efficiency. Furthermore, using a compound having these substituents in the hole transport layer can also lower the refractive index. In particular, using a compound having a triazine ring and an alkyl group in the electron transport layer and a compound having a triarylamine skeleton and an alkyl group in the hole transport layer can synergistically enhance the light extraction efficiency improvement effect. Furthermore, the alkyl group can be made to have multiple carbon atoms, preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more, to enhance the effect. A layer using a compound having a fluoro group as a substituent is also preferred because it can lower the refractive index. In particular, having multiple fluoro groups can enhance the refractive index improvement effect. It is also effective to use a compound having a fluoro group in both the electron transport layer and the hole transport layer.

[0186] In addition, a compound having a cyano group as a substituent is preferable because it can improve the electron transport property.

[0187] It is also preferable to combine a polycyclic aromatic ring, an alkyl group, a fluoro group, or a cyano group as a substituent. For example, when a polycyclic aromatic ring and a cyano group are used as a substituent, both heat resistance and electron transport properties can be improved. Furthermore, when a polycyclic aromatic ring and an alkyl group are used as a substituent, both heat resistance and light extraction efficiency can be improved. In this way, a combination of substituents can be used depending on the desired function.

[0188] Furthermore, the heat resistance can be further improved by including a plurality of polycyclic aromatic rings as substituents. In this case, it is preferable that the aromatic hydrocarbon ring and the heteroaromatic ring are included.

[0189] Specific examples of the organic compound having a triazine ring include 2-(biphenyl-4-yl)-4-phenyl-6-(9,9′-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), and 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine. azine (abbreviation: mBnfBPTzn-02), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mF BPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridin nyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenylindolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3′-(triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-[8-([1,1':4',1''-terphenyl]-4-yl)-1-dibenzofuranyl]-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-[4-(2-naphthyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)T zn), 9,9'-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazine-2,4-diyl}bis(9H-carbazole) (abbreviation: SiTrzCz2), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-(biphenyl-3-yl)indolo[2,3-a]carbazole (abbreviation: BP-mBPIcz(II)Tz n), 3-{3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]phenyl}-9-phenyl-9H-carbazole (abbreviation: mPCPDBfTzn), 9,9′-[6-(biphenyl-4-yl)-2-phenyl-1,3,5-triazine-4,3″-diyl]bis(9H-carbazole) (abbreviation: Cz-pmCzBPTzn), 3-phenyl-9-[4-phenyl-6-(9-phenyl-3-dibenzofuranyl)-1,3,5-triazin-2-yl]-9H-carbazole (abbreviation: PDBf-PCzTzn), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzothienyl]-2-phenyl-9H-carbazole (abbreviation: PCzDBtTzn), 2,4-diphenyl-6-[3'-(spiro[7H-benzo[c]fluorene-7,9'-[9H]xanthene]-2'-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: mSbfxBPTzn), 3'-[4-phenyl-6-(spiro[9H-fluorene-9,9'-[9H]xanthene]-2'-yl)-1,3,5-triazin-2-yl]biphenyl-4-carbonitrile (abbreviation: mpCNBP-SFxTzn), 2,2'-(1,2-naphthalenediyldi-4,1-phenylene)bis[4,6-diphenyl-1,3,5-triazine] (abbreviation: TznP2N), etc. In particular, TznP2N represented by structural formula (500), mSbfxBPTzn represented by structural formula (501), mpCNBP-SFxTzn represented by structural formula (502), CNBPNPTzn represented by structural formula (503), βNP-SFx(4)Tzn represented by structural formula (504), mmtBuBP-mDMePyPTzn represented by structural formula (505), and mBnfBPTzn represented by structural formula (506) are preferred. These organic compounds can also be used as host materials in the light-emitting layer.

[0190]

[0191] Furthermore, materials that can be used for the electron transport layer included in the light-emitting unit on the anode side include those having an electron mobility of 1×10 at a square root of an electric field strength [V / cm] of 600 or less. −７ cm ２ / Vs or more, preferably 1×10 −６ cm ２ A substance having an electron mobility of 1 / Vs or more is preferred. Note that, other substances can be used as long as they have a higher electron transporting property than holes. Note that, as the organic compound, an organic compound having a π-electron-deficient heteroaromatic ring is preferred. As the organic compound having a π-electron-deficient heteroaromatic ring, for example, one or more of an organic compound having a heteroaromatic ring containing an azole ring, an organic compound having a heteroaromatic ring containing a pyridine ring, an organic compound having a heteroaromatic ring containing a diazine skeleton, and an organic compound having a triazine ring are preferred, and an organic compound having a heteroaromatic ring containing a triazine ring is particularly preferred.

[0192] As organic compounds having electron transport properties that can be used in the electron transport layer included in the light-emitting unit on the anode side, compounds having electron transport properties described below can be used. In particular, organic compounds having a heteroaromatic ring containing a diazine ring, organic compounds having a heteroaromatic ring containing a pyridine ring, and organic compounds having a triazine ring are preferred because they have good reliability. In particular, organic compounds having a heteroaromatic ring containing a diazine (pyrimidine or pyrazine) ring and organic compounds having a triazine ring have high electron transport properties and can reduce driving voltage.

[0193] <Intermediate Layer> In addition, in one embodiment of the present invention, in the tandem light-emitting device, the intermediate layer 160 preferably contains an organic compound having a phenanthroline ring.

[0194] The organic compound having the phenanthroline ring has an electron mobility of 1×10 at a square root of an electric field strength [V / cm] of 600. −７ cm ２ / Vs or more, preferably 1×10 −６ cm ２ It is preferable that the material has an electron mobility of 1 / Vs or more. Note that other materials can be used as long as they have a higher electron transporting property than holes.

[0195] The organic compound having a phenanthroline ring is preferably a compound containing a phenanthroline ring and an aromatic ring, and the aromatic ring may be a monocyclic aromatic ring or a polycyclic aromatic ring.

[0196] Examples of the monocyclic aromatic ring include a benzene ring, a pyrrole ring, a pyridine ring, and a pyrimidine ring. Furthermore, the polycyclic aromatic ring preferably includes an aromatic hydrocarbon ring such as a naphthalene ring, a phenanthrene ring, a chrysene ring, a triphenylene ring, and a fluorene ring, and a heteroaromatic ring such as a phenanthroline ring and a pyrrole ring. In particular, the inclusion of a plurality of these polycyclic aromatic rings is preferred because it can improve heat resistance or electron transport properties.

[0197] Examples of organic compounds having a phenanthroline ring include bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2′-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: mTpPPhen), and 2-phenyl-9-(2

[0043] An organic compound having a heteroaromatic ring containing a phenanthroline ring, such as 2-[4-(9-phenanthryl)-1-naphthyl]-1,10-phenanthroline (abbreviation: Ph-TpPhen), 2-[4-(9-phenanthryl)-1-naphthyl]-1,10-phenanthroline (abbreviation: PnNPhen), or 2-[4-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen), can be used. However, PnNPhen shown in the following structural formula (200) or mPPhen2P shown in the structural formula (201) is particularly preferred.

[0198]

[0199] In the light-emitting device of one embodiment of the present invention, the intermediate layer may have any structure as long as it contains an organic compound having a phenanthroline ring and can inject electrons into the light-emitting unit on the anode side and holes into the light-emitting unit on the cathode side, both of which are in contact with the intermediate layer, by applying a voltage between the first electrode and the second electrode. However, as shown in Figure 1A, the intermediate layer 160 preferably has a stacked structure including a first layer 161 containing an organic compound and a second layer 162 located closer to the cathode than the first layer.

[0200] The first layer preferably contains a metal or a metal compound in addition to an organic compound, and the metal or metal compound is preferably an alkali metal (Group 1 element) such as Li, an alkaline earth metal (Group 2 element) such as Mg or Ca, a Group 3 element including a lanthanoid such as Y, Eu, or Yb, a Group 11 element such as Cu, Ag, or Au, a Group 12 element such as Zn, or an earth metal (Group 13 element) such as Al or In.

[0201] The first layer may have a stacked structure of a layer containing an organic compound and a layer containing a metal or a metal compound located closer to the cathode than the layer containing the organic compound. Alternatively, the first layer may be a mixed layer of an organic compound and a metal or a metal compound. The mixed layer is preferable for the first layer because it requires fewer deposition chambers and reduces manufacturing costs, and also contributes to improving the stability of the light-emitting device.

[0202] When an organic compound and a metal or metal compound are mixed, when the first layer is analyzed in the film thickness direction, the distribution of the organic compound and the distribution of the metal or metal compound show roughly the same tendency. That is, when the distribution of the organic compound is constant, the distribution of the metal or metal compound is also roughly constant. In the case of a laminated structure of a layer containing an organic compound and a layer having a metal or metal compound, the metal or metal compound may be detected in regions other than the layer having the metal or metal compound due to diffusion from the layer having the metal or metal compound, but since the distribution shows a different distribution from the distribution of the organic compound, the analysis results can be distinguished between diffusion and mixing.

[0203] Furthermore, when the first layer is analyzed in the film thickness direction, if there is a region in which a metal or metal compound is detected that is 10 nm or more in thickness, preferably 15 nm or more, and more preferably 20 nm or more in thickness, the first layer can be considered to have a mixed layer in which an organic compound and a metal or metal compound are mixed.

[0204] Among these, the metal in the metal or metal compound is preferably a substance that exhibits donor properties to an organic compound having a phenanthroline ring. Examples of substances that exhibit donor properties to an organic compound having a phenanthroline ring include metals of Group 1 and Group 2, and lithium or lithium compounds are particularly preferred. Specifically, Li, lithium fluoride (LiF), lithium oxide (Li ２Preferred examples of the light-emitting device of the present invention include 8-quinolinolato-lithium (abbreviation: Liq), 8-quinolinolato-lithium (abbreviation: Liq), and the like. When the first layer contains an organic compound having a phenanthroline ring and a substance that exhibits donor properties to the organic compound having the phenanthroline ring, electrons are generated by charge separation, and when a voltage is applied between the first electrode and the second electrode, the electrons are injected into the light-emitting unit on the anode side via the organic compound having the phenanthroline ring. As a result, the light-emitting device of one embodiment of the present invention can be a light-emitting device with low driving voltage.

[0205] In addition to the organic compounds having a phenanthroline ring, organic compounds having a phenanthroline ring with an electron-donating substituent are preferred. The phenanthroline ring has a skeleton that easily interacts with metals, etc., and when such an organic compound having a phenanthroline ring further has an electron-donating group, the electron density of the phenanthroline ring increases, making it easier to interact with the metal or metal compound. In particular, when a metal belonging to Groups 3, 11, 12, or 13 is used as the metal or the metal compound, a tandem light-emitting device having excellent characteristics and suppressing an increase in driving voltage can be provided.

[0206] Specific examples of the electron-donating group include an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group. However, the electron-donating group that is preferably introduced into the phenanthroline ring is not limited to these. Any group that can increase the electron density of the phenanthroline ring by introducing it into the phenanthroline ring can be used as the electron-donating group. In addition, the electron-donating group may be introduced into the phenanthroline ring via an arylene group such as a phenylene group, and the arylene group is preferably a p-phenylene group.

[0207] Specific examples of organic compounds having a phenanthroline ring with an electron-donating substituent are shown in structural formulas (203) to (210). Specific examples of organic compounds that are not organic compounds having a phenanthroline ring but can be used in the intermediate layer are shown in structural formulas (211) to (213).

[0208]

[0209] In addition, a configuration in which the first layer contains an element of Group 1 or Group 2, particularly lithium or a lithium compound, and an organic compound having a phenanthroline ring with an electron-donating substituent is preferable because it can provide a tandem light-emitting device with lower driving voltage and better reliability.Furthermore, a configuration in which the first layer contains an element of Group 1 or Group 2, particularly lithium or a lithium compound, and an organic compound having a phenanthroline ring with an electron-donating substituent is preferable because it can suppress an increase in driving voltage when the organic compound of the light-emitting device is processed by photolithography.

[0210] In an intermediate layer having the configuration described above, organic compounds having a phenanthroline ring, particularly organic compounds having a 1,10-phenanthroline ring, are preferred because the two nitrogen atoms contained therein can coordinate to a metal, and therefore interaction with the metal or metal compound is likely to occur.

[0211] When an electron-donating group is introduced into the 1,10-phenanthroline ring, the electron-donating group is preferably substituted at positions 4 and 7 of the 1,10-phenanthroline ring. By introducing the electron-donating group into positions 4 and 7 of the 1,10-phenanthroline ring, the electron density of the nitrogen atoms at positions 1 and 10 can be increased, making it easier for the compound to interact with a metal or metal compound.

[0212] The first layer may further contain an organic compound different from the organic compound having a phenanthroline ring. The organic compound is preferably an organic compound having electron transport properties. In particular, the organic compound preferably has two or more heteroaromatic rings bonded or condensed to each other, and the two or more heteroaromatic rings preferably have a total of three or more heteroatoms. By including such an organic compound in the first layer, improvements in heat resistance and electron transport properties can be achieved.

[0213] The second layer 162 preferably contains an organic compound having hole-transporting properties. The second layer 162 preferably further contains a substance exhibiting acceptor properties, and the substance exhibiting acceptor properties is preferably an organic compound that exhibits acceptor properties to an organic compound having hole-transporting properties. As the substance exhibiting acceptor properties, an organic compound having at least one of a halogen group and a cyano group is particularly preferred, and an organic compound having at least one of a fluorine group and a cyano group is more preferred. It is more preferred that the organic compound contains four or more halogen groups (fluorine) and cyano groups in total.

[0214] When the second layer 162 is a layer containing an organic compound having a hole-transporting property and a substance that exhibits acceptor properties for the organic compound having a hole-transporting property, holes are generated by charge separation, and when a voltage is applied between the first electrode and the second electrode, the holes are injected into the light-emitting unit on the cathode side through the organic compound having a hole-transporting property. Thus, the light-emitting device of one embodiment of the present invention can be a light-emitting device with low driving voltage.

[0215] The intermediate layer may have a third layer 163 between the first layer 161 and the second layer 162 .

[0216] The third layer 163 contains a compound having an electron transporting property and has functions such as reducing the driving voltage by smoothing the transfer of electrons between the first layer 161 and the second layer 162 and improving reliability by reducing the interaction between the first layer 161 and the second layer 162.

[0217] The thickness of the third layer 163 is preferably 1 nm to 10 nm, more preferably 2 nm to 5 nm, in order to suppress an increase in driving voltage.

[0218] The light-emitting device of the present invention having the above-described structure can be a light-emitting device with high current efficiency, low energy loss, and favorable characteristics. In addition, a display device according to one embodiment of the present invention using such a light-emitting device can be a display device with low power consumption, high reliability, and high luminance and thus favorable visibility.

[0219] The first electrode 101 is an electrode including an anode. The first electrode 101 may have a stacked structure, in which case the layer in contact with the organic compound layer 103 functions as the anode. The anode is preferably formed using a metal, alloy, conductive compound, or mixture thereof having a high work function (specifically, 4.0 eV or higher). Specific examples include indium oxide-tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). These conductive metal oxide films are usually formed by sputtering, but may also be formed by applying a sol-gel method or the like. For example, indium oxide-zinc oxide can be formed by sputtering using a target containing indium oxide and 1 to 20 wt % zinc oxide. Indium oxide containing tungsten oxide and zinc oxide (IWZO) can also be formed by sputtering using a target containing 0.5 to 5 wt % tungsten oxide and 0.1 to 1 wt % zinc oxide relative to indium oxide. Other materials that can be used for the anode include, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), and nitrides of metal materials (e.g., titanium nitride). Alternatively, graphene can be used for the anode. Note that by using the composite material that forms the first layer 161 (also referred to as a P-type layer) in the intermediate layer 160 as a layer in contact with the anode (typically a hole-injection layer), it becomes possible to select an electrode material regardless of the work function.

[0220] The hole injection layer 111 is provided in contact with the anode and has a function of facilitating injection of holes into the organic compound layer 103 (first light-emitting unit 501). ２The organic EL element can be formed from a phthalocyanine compound or complex compound such as copper phthalocyanine (abbreviated as CuPc), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) or 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), or a polymer such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviated as PEDOT / PSS).

[0221] The hole-injection layer 111 may be formed using a substance having electron acceptor properties. Examples of the substance having acceptor properties include organic compounds having an electron-withdrawing group (such as a halogen group or a cyano group), such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile. In particular, compounds in which an electron-withdrawing group is bonded to a fused aromatic ring having a plurality of heteroatoms, such as HAT-CN, are thermally stable and preferred. Also, [3]radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group, a cyano group, etc.) are preferred because they have very high electron-accepting properties, and specific examples thereof include α,α',α''-1,2,3-cyclopropanetriylidenetris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenetris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenetris[2,3,4,5,6-pentafluorobenzeneacetonitrile]. In addition to the organic compounds described above, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can also be used as the acceptor material. ２The hole injection layer 111 can also be formed from a phthalocyanine compound or complex compound such as copper phthalocyanine (abbreviated as CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) or 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), or a polymer such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviated as PEDOT / PSS). A substance having acceptor properties can extract electrons from an adjacent hole transport layer (or hole transport material) when an electric field is applied.

[0222] The hole-injection layer 111 is preferably formed using a composite material containing the above-mentioned material having an acceptor property and a compound having a hole-transport property.

[0223] As the compound having hole transport properties used in the composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. −６ cm ２ / Vs or more. The compound having hole transport properties used in the composite material is preferably a compound having a fused aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. Examples of the fused aromatic hydrocarbon ring include an anthracene ring and a naphthalene ring. Examples of the π-electron-rich heteroaromatic ring are preferably fused aromatic rings containing at least one of a pyrrole ring, a furan ring, and a thiophene ring. Specifically, examples of the π-electron-rich heteroaromatic ring include a carbazole ring, a dibenzothiophene ring, and a ring in which an aromatic ring or a heteroaromatic ring is fused to one of these rings. Examples of the compound having hole transport properties used in the composite material include organic compounds selected from compounds having hole transport properties that can be used in a host material and organic compounds that can be used in a hole-transport layer.

[0224] By forming the hole injection layer 111, the hole injection property becomes good, and a light emitting device with a low driving voltage can be obtained.

[0225] Among substances having acceptor properties, organic compounds having acceptor properties are easy to use because they can be easily vapor-deposited and formed into a film.

[0226] The hole-transporting layers (the first hole-transporting layer 112_1 and the second hole-transporting layer 112_2) are formed by containing an organic compound having a hole-transporting property. −６ cm ２ In addition to the organic compounds having an amine skeleton and a fluorene ring described above, organic compounds having a hole transporting property can be used as needed.

[0227] Examples of the compound having hole transport properties include 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N′-diphenyl-N,N′-bis(3-methylphenyl)-4,4′-diaminobiphenyl (abbreviation: TPD), N,N′-bis(9,9′-spirobi[9H-fluoren]-2-yl)-N,N′-diphenyl-4,4′-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3-methylphenyl-4,4′-diaminobiphenyl (abbreviation: 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), 4-phenyl-3-methylphenyl-4,4′-diaminobiphenyl (abbreviation: 4,4′-bis[N-(1-naphthyl)-N-phenylamino] ... '-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl compounds having a triarylamine skeleton such as 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-diphenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), (N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-Bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-(2-naphthyl)-9'-[1,1' :4',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3 9,9'-bis(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-bis(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, compounds having a carbazole ring such as N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, and 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviation: PSiCzCz); 4,4',4"-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II);Examples of suitable compounds include compounds having a thiophene ring, such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan ring, such as 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the compounds mentioned above, compounds having a triarylamine skeleton and compounds having a carbazole ring are preferred because they have good reliability, high hole transport properties, and contribute to reducing driving voltage. In addition, the organic compounds listed as compounds having hole transport properties used in the composite material of the hole injection layer 111 can also be suitably used as materials for forming the hole transport layer 112 (the first hole transport layer 112_1 and the second hole transport layer 112_2).

[0228] The light-emitting layers (the first light-emitting layer 113_1 and the second light-emitting layer 113_2) preferably contain a light-emitting substance and a host material. Note that the light-emitting layers may also contain other materials.

[0229] Furthermore, the first light-emitting layer 113_1 and the second light-emitting layer 113_2 are preferably light-emitting layers that emit light of similar colors. For example, red, green, and blue pixels are often used in display devices to express full colors. In a light-emitting device used for a red pixel, the first light-emitting layer 113_1 and the second light-emitting layer 113_2 are both light-emitting layers that emit red light. In a light-emitting device used for a green pixel, both of the two light-emitting layers are light-emitting layers that emit green light. In a light-emitting device used for a blue pixel, both of the two light-emitting layers emit blue light. Specifically, the first light-emitting layer 113_1 and the second light-emitting layer 113_2 are light-emitting layers that emit light of similar colors. Specifically, the light-emitting substance contained in the first light-emitting layer 113_1 and the light-emitting substance contained in the second light-emitting layer 113_2 are preferably compounds whose difference in maximum peak wavelength in their emission spectra (fluorescence spectra) is 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less. Note that it is more preferable that the light-emitting substance contained in the first light-emitting layer 113_1 is the same as the light-emitting substance contained in the second light-emitting layer 113_2.

[0230] In a display device using red, green, and blue pixels to display full colors, a phosphorescent material may be used as the light-emitting material 133 and a fluorescent material as the light-emitting material 134 in one of the red, green, and blue pixels, a fluorescent material may be used in another pixel, and a phosphorescent material may be used in the remaining pixels. Alternatively, a phosphorescent material may be used as the light-emitting material 133 and a fluorescent material as the light-emitting material 134 in one of the red, green, and blue pixels, and a phosphorescent material may be used in the other pixels. Alternatively, a phosphorescent material may be used as the light-emitting material 133 and a fluorescent material as the light-emitting material 134 in one of the red, green, and blue pixels, and a fluorescent material may be used in the other pixels. Such a configuration can provide a highly efficient display device.

[0231] When a fluorescent substance is used as the light-emitting substance in the light-emitting layer, the fluorescent substance may be, in addition to the above-mentioned fluorescent substances, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2′-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4′-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2′-bipyridine (abbreviation: PAPP2BPy), N,N′-diphenyl-N,N′-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAP rn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10 -diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenyl) N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA] 9,10-bis(biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenyl Nyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-2-methyl-4H-pyran-4-ylidene Phenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1 ,6-pyrene-diyl)bis[(6-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazol-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), and N,N'-bis(dibenzofuran-3-yl)-N,N'-diphenylnaphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10FrA2Nbf(IV)-02). In addition to the fluorescent substances described above, known fluorescent substances may also be selected and used. In addition, compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium atoms can also be used.

[0232] In addition to these, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-G), 9,11-bis[ Compounds having an indole skeleton such as 3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-Y) can be preferably used. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium atoms can also be used.

[0233] When a phosphorescent substance is used as the light-emitting substance in the light-emitting layer, the phosphorescent substance may be any of the above-described phosphorescent substances. In addition to the above-described phosphorescent substances, a known phosphorescent substance may also be selected and used.

[0234] As the host material of the light-emitting layer, in addition to the organic compounds described above, various carrier transporting materials such as the compounds having the electron transporting property and / or the compounds having the hole transporting property described above, and the TADF materials described above can be used.

[0235] When a phosphorescent substance is used as the light-emitting substance in the light-emitting layer, it is preferable to use, as the host material, two types of organic compounds that form an exciplex as described above, which can provide a light-emitting device with high luminous efficiency.

[0236] The TADF materials that can be used as host materials can be the same as those described above. When a fluorescent or phosphorescent substance is used as the light-emitting substance, using a TADF material as the host material allows triplet excitation energy generated in the TADF material to be converted into singlet excitation energy by reverse intersystem crossing, and then the energy is transferred to the light-emitting substance, thereby improving the luminous efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the light-emitting substance functions as an energy acceptor.

[0237] This is very effective when the luminescent material is a fluorescent luminescent material. １ The level is the S of the fluorescent material. １ It is preferable that the T of the TADF material is higher than the T level. １ The level is the S of the fluorescent material. １ Therefore, the T １ The level is the T １ It is preferable that the level is higher than the energy level. It is also preferable to use a TADF material that emits light that overlaps with the wavelength of the lowest-energy absorption band of the fluorescent material. This is preferable because it allows smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient light emission.

[0238] When a fluorescent emitting substance is used as the emitting substance, a material having an anthracene ring is suitable as the host material. Using a substance having an anthracene ring as the host material for a fluorescent emitting substance makes it possible to realize an emitting layer with both excellent luminous efficiency and durability. As a substance having an anthracene ring to be used as the host material, a substance having a diphenylanthracene ring, particularly a 9,10-diphenylanthracene ring, is preferred because it is chemically stable. Furthermore, a host material having a carbazole ring is preferred because it enhances hole injection and transport properties. However, a host material containing a benzocarbazole ring, in which a benzene ring is further condensed with a carbazole ring, is more preferred because its HOMO is about 0.1 eV higher than that of a carbazole ring, making it easier for holes to enter. In particular, a host material containing a dibenzocarbazole ring is preferred because its HOMO is about 0.1 eV higher than that of a compound containing a carbazole ring, making it easier for holes to enter, and it also has excellent hole transport properties and high heat resistance. Therefore, a more preferable host material is a substance having both a 9,10-diphenylanthracene ring and a carbazole ring (or a benzocarbazole ring or a dibenzocarbazole ring). Note that, from the viewpoint of the hole injection / transport property, a benzofluorene ring or a dibenzofluorene ring may be used instead of the carbazole ring.Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-[4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4' -yl]anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,βADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthryl)benzo Examples include zo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthryl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), etc. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred choices because they exhibit very good properties.

[0239] The first electron-transporting layer 114_1 is a layer containing a compound having an electron-transporting property. The compound having an electron-transporting property is a compound having an electron mobility of 1×10 or less at a square root of an electric field strength [V / cm] of 600. −７ cm ２ / Vs or more, preferably 1×10 −６ cm ２A substance having an electron mobility of 1 / Vs or more is preferred. Note that, other substances can be used as long as they have a higher electron transport property than holes. Note that, as the organic compound, an organic compound having a π-electron-deficient heteroaromatic ring is preferred. As the organic compound having a π-electron-deficient heteroaromatic ring, for example, one or more of an organic compound having a heteroaromatic ring containing an azole ring, an organic compound having a heteroaromatic ring containing a pyridine ring, an organic compound having a heteroaromatic ring containing a diazine ring, and an organic compound having a triazine ring are preferred, and an organic compound having a heteroaromatic ring containing a triazine ring is particularly preferred.

[0240] As the organic compound having electron-transporting properties that can be used in the first electron-transporting layer 114_1, organic compounds that can be used as the organic compound having electron-transporting properties of the host material in the first light-emitting layer 113_1 and the second light-emitting layer 113_2 can be used as well. Among them, organic compounds having a heteroaromatic ring containing a diazine ring, organic compounds having a heteroaromatic ring containing a pyridine ring, and organic compounds having a triazine ring are preferred because of their high reliability. In particular, organic compounds having a heteroaromatic ring containing a diazine (pyrimidine or pyrazine) ring and organic compounds having a triazine ring have high electron-transporting properties and contribute to reducing driving voltage.

[0241] As described above, the second electron-transporting layer 114_2 is a layer containing an organic compound having a triazine ring. Details thereof have already been described, so they will not be repeated here.

[0242] Note that the first electron-transport layer 114_1 preferably contains an organic compound having a triazine ring in order to reduce power consumption. In particular, it is preferable that the first electron-transport layer 114_1 contains an organic compound having the same triazine ring as the organic compound having a triazine ring contained in the second electron-transport layer 114_2, because this prevents the manufacturing apparatus from becoming complicated and is advantageous in terms of raw material procurement costs.

[0243] Furthermore, since the first electron-transport layer 114_1 contains an organic compound that does not contain a triazine ring, it becomes easier to control the carrier transport property, and it becomes possible to provide a light-emitting device with better characteristics. As the organic compound that does not contain a triazine ring, an organic compound that has a heteroaromatic ring that includes a pyridine ring, or an organic compound that has a heteroaromatic ring that includes a diazine (pyrimidine or pyrazine) ring is preferable.

[0244] The electron injection layer 115 has a function of promoting electron injection by reducing the electron injection barrier from the second electrode 102, and for example, a Group 1 metal, a Group 2 metal, or an oxide, halide, or carbonate thereof can be used. In addition, a composite material of the above-mentioned compound having electron transport properties and a material exhibiting electron donating properties can also be used. Examples of materials exhibiting electron donating properties include Group 1 metals, Group 2 metals, or oxides thereof. Specifically, lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF), calcium fluoride (CaF ２ ), lithium oxide (Li ２ Alkali metals, alkaline earth metals, or compounds thereof such as erbium fluoride (ErF ３ A rare earth metal compound such as ZnO, ZnS, ZnO, ZnSe ...

[0245] The electron-injection layer 115 may also be formed using a composite material obtained by mixing an organic compound and an electron donor (donor). Such composite materials have excellent electron-injection and electron-transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent at transporting the generated electrons. Specifically, for example, the above-described substances constituting the electron-transport layer can be used. The electron donor may be any substance that exhibits electron-donating properties to the organic compound. Specifically, alkali metals, alkaline earth metals, or rare earth metals are preferred, such as lithium, sodium, cesium, magnesium, calcium, erbium, and ytterbium. Alkali metal oxides or alkaline earth metal oxides are preferred, such as lithium oxide, calcium oxide, and barium oxide. Lewis bases such as magnesium oxide can also be used. Organic compounds such as tetrathiafulvalene (abbreviated as TTF) can also be used.

[0246] The second electrode 102 is an electrode including a cathode. The second electrode 102 may have a stacked structure, in which case the layer in contact with the organic compound layer 103 functions as the cathode. Materials that form the cathode include metals, alloys, electrically conductive compounds, and mixtures thereof, each having a small work function (specifically, 3.8 eV or less). Specific examples of such cathode materials include alkali metals such as lithium (Li) or cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), alloys containing these elements (MgAg, AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these elements. Specific examples include lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF), and the like. ２Examples of the electride include alkali metals, alkaline earth metals, rare earth metals, such as lithium (8-quinolinolato) (abbreviation: Liq), and ytterbium (Yb), or compounds or complexes thereof, or electrides. Examples of the electride include a substance in which a high concentration of electrons is added to a mixed oxide of calcium and aluminum. It is also possible to use a mixture of two or more of these. When the second electrode 102 has a stacked structure, materials with good conductivity can be used for the components other than the cathode, regardless of the work function.

[0247] Note that the second electron-transport layer 114_2 is preferably in contact with the second electrode 102. When the second electron-transport layer 114_2 is in contact with the second electrode 102, a light-emitting device having excellent electron-injection and electron-transport properties, low driving voltage, and low power consumption can be provided.

[0248] Note that when the second electrode 102 is formed using a material that is transparent to visible light, a light-emitting device that emits light from the second electrode 102 side can be obtained.

[0249] These conductive materials can be formed into films by dry methods such as vacuum deposition or sputtering, inkjet methods, spin coating methods, etc. Alternatively, they may be formed by wet methods using a sol-gel method, or by wet methods using a paste of a metal material.

[0250] In addition, various methods, whether dry or wet, can be used to form the organic compound layer 103. For example, vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, spin coating, or the like may be used.

[0251] Furthermore, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0252] 3 shows two adjacent light-emitting devices (light-emitting device 130a and light-emitting device 130b) included in a display device of one embodiment of the present invention. The light-emitting device 130a and the light-emitting device 130b emit light of different colors. Specifically, the difference in the maximum peak wavelengths in the electroluminescence spectra of the light-emitting devices is greater than 30 nm.

[0253] The light-emitting device 130a includes an organic compound layer 103a between a first electrode 101a and a second electrode 102 on an insulating layer 175. The organic compound layer 103a includes a first light-emitting unit 501a and a second light-emitting unit 502a, which are stacked with an intermediate layer 160a sandwiched therebetween. While FIG. 3 illustrates an example in which two light-emitting units are stacked, a structure in which three or more light-emitting units are stacked may also be used. The first light-emitting unit 501a includes a hole-injection layer 111a, a first hole-transport layer 112a_1, a first light-emitting layer 113a_1, and a first electron-transport layer 114a_1. The intermediate layer 160a includes a second layer 162a, a third layer 163a, and a first layer 161a. The third layer 163a is optional. The second light-emitting unit 502a includes a second hole-transporting layer 112a_2, a second light-emitting layer 113a_2, and a second electron-transporting layer 114a_2.

[0254] The light-emitting device 130b includes an organic compound layer 103b between a first electrode 101b and a second electrode 102 on an insulating layer 175. The organic compound layer 103b includes a first light-emitting unit 501b and a second light-emitting unit 502b stacked with an intermediate layer 160b sandwiched therebetween. While FIG. 3 illustrates an example in which two light-emitting units are stacked, a structure in which three or more light-emitting units are stacked may also be used. The first light-emitting unit 501b includes a hole-injection layer 111b, a first hole-transport layer 112b_1, a first light-emitting layer 113b_1, and a first electron-transport layer 114b_1. The intermediate layer 160b includes a second layer 162b, a third layer 163b, and a first layer 161b. The third layer 163b is optional. The second light-emitting unit 502b includes a second hole-transporting layer 112b_2, a second light-emitting layer 113b_2, and a second electron-transporting layer 114b_2.

[0255] The first hole transport layer 112 a_1 and the second hole transport layer 112 a_2 have a stacked structure, and the layer in contact with the light-emitting layer is formed using a material whose LUMO level is higher than the LUMO level of the material constituting the light-emitting layer (at least the host material, preferably the material constituting the light-emitting layer, the material having the largest composition ratio among the materials constituting the light-emitting layer, or the material having the highest LUMO level among the materials constituting the light-emitting layer).

[0256] The second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 are layers containing an organic compound having a triazine ring. The first layer 161a and the first layer 161b are layers containing an organic compound having a phenanthroline ring.

[0257] The first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are preferably light-emitting layers that emit light of similar colors. The light-emitting substances contained in each of the first and second light-emitting layers are preferably compounds whose emission spectra have a maximum peak wavelength difference of 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less, and it is even more preferable that the light-emitting substances contained in each of the first and second light-emitting layers 113b_1 and 113b_2 are light-emitting layers that emit light of similar colors. The light-emitting substances contained in each of the first and second light-emitting layers are preferably compounds whose emission spectra have a maximum peak wavelength difference of 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less, and it is even more preferable that the light-emitting substances contained in each of the first and second light-emitting layers 113b_1 and 113b_2 are the same.

[0258] It is preferable that the first light-emitting layer 113a_1 and the first light-emitting layer 113b_1 are separated, and the second light-emitting layer 113a_2 and the second light-emitting layer 113b_2 are separated. It is preferable that the emission colors of the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are different from the emission colors of the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2. It is preferable that the light-emitting substance contained in the first light-emitting layer 113a_1 is different from the light-emitting substance contained in the first light-emitting layer 113b_1, and that the light-emitting substance contained in the second light-emitting layer 113a_2 is different from the light-emitting substance contained in the second light-emitting layer 113b_2.

[0259] The hole injection layer 111a and the hole injection layer 111b, the first hole transport layer 112a_1 and the first hole transport layer 112b_1, the first electron transport layer 114a_1 and the first electron transport layer 114b_1, the intermediate layer 160a and the intermediate layer 160b (the second layer 162a and the second layer 162b, the third layer 163a and the third layer 163b, and the first layer 161a and the first layer 161b), the second hole transport layer 112a_2 and the second hole transport layer 112b_2, and the second electron transport layer 114a_2 and the second electron transport layer 114b_2 may each be a continuous layer, or may be independently separated in the light-emitting device 130a and the light-emitting device 130b. Being continuous layers improves productivity and enables light-emitting devices to be produced at low cost. The separate layers for each light-emitting device allow the use of materials suited to the emission color, thereby enabling the manufacture of a light-emitting device or display device with excellent characteristics. In particular, the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 are preferably continuous layers, because this allows both the light-emitting device 130a and the light-emitting device 130b to have excellent characteristics.

[0260] Being a continuous layer means that the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 are layers formed of the same material. That is, when the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 are layers formed of the same material, both the light-emitting device 130a and the light-emitting device 130b can be light-emitting devices with excellent characteristics. Furthermore, it is more preferable that the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 be layers having similar structures, and it is even more preferable that they be layers having the same structure.

[0261] Furthermore, when the light-emitting substance contained in the first light-emitting layer 113a_1 is different from the light-emitting substance contained in the first light-emitting layer 113b_1, and the light-emitting substance contained in the second light-emitting layer 113a_2 is different from the light-emitting substance contained in the second light-emitting layer 113b_2 (for example, when the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are blue fluorescent light-emitting layers and the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2 are green phosphorescent light-emitting layers, or when the first light-emitting layer 113a_1 and the second light-emitting layer 113b_2 are blue fluorescent light-emitting layers and green phosphorescent light-emitting layers, respectively, the light-emitting substance contained in the second light-emitting layer 113b_2 is different from the light-emitting substance contained in the second light-emitting layer 113b_2 (for example, when the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are blue fluorescent light-emitting layers and the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2 are green phosphorescent light-emitting layers), For example, when the light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are blue fluorescent light-emitting layers and the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2 are red phosphorescent light-emitting layers, or when the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are green phosphorescent light-emitting layers and the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2 are red phosphorescent light-emitting layers, the carrier balances of the light-emitting layers of the light-emitting devices 130a and 130b are different. Therefore, in order to maximize the performance of each of the light-emitting devices 130a and 130b, it is usually necessary to select and change appropriate intermediate layers and electron-transporting layers for each of the light-emitting devices. However, by using a layer containing an organic compound having a triazine ring as the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 and using a layer containing an organic compound having a phenanthroline ring as the first layer 161a and the first layer 161b, it is possible to obtain the performance of both the light-emitting device 130a and the light-emitting device 130b even if the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 have the same structure. In other words, it is possible to achieve both improved productivity and improved performance. Note that the first layer 161a and the first layer 161b may have the same structure.

[0262] The continuous layer is a so-called common layer formed across both the light-emitting device 130a and the light-emitting device 130b.

[0263] 4A is a modified example of FIG. 3. Light-emitting device 130a and light-emitting device 130b emit light of different colors, and therefore have different optical path lengths between electrodes that can amplify light emission using a microcavity structure. Therefore, in light-emitting device 130b1, the distance between the electrodes can be adjusted by increasing the thickness of light-emitting layers such as light-emitting layer 113b_11 and light-emitting layer 113b_21. Alternatively, the optical path length may be changed by thickening or adding a functional layer, such as hole-transport layer 112b_21.

[0264] 4B illustrates three adjacent light-emitting devices (light-emitting device 130a, light-emitting device 130b1, and light-emitting device 130c) included in a display device of one embodiment of the present invention. The light-emitting device 130a, the light-emitting device 130b1, and the light-emitting device 130c emit light of different colors.

[0265] The light-emitting device 130c includes an organic compound layer 103c between a first electrode 101c and a second electrode 102 on an insulating layer 175. The organic compound layer 103c includes a first light-emitting unit 501c and a second light-emitting unit 502c stacked with an intermediate layer 160c sandwiched therebetween. While FIG. 4B illustrates an example in which two light-emitting units are stacked, a configuration in which three or more light-emitting units are stacked may also be used. The first light-emitting unit 501c includes a hole-injection layer 111c, a first hole-transport layer 112c_1, a first light-emitting layer 113c_1, and a first electron-transport layer 114c_1. The intermediate layer 160c includes a second layer 162c, a third layer 163c, and a first layer 161c. The third layer 163c is optional. The second light-emitting unit 502c includes a second hole-transporting layer 112c_2, a second light-emitting layer 113c_2, and a second electron-transporting layer 114c_2.

[0266] The light-emitting device 130c is assumed to emit light with a shorter wavelength than the light-emitting devices 130a and 130b1. The inter-electrode distance of the light-emitting device 130c is adjusted by making the film thicknesses of the first light-emitting layer 113c_1 and the second light-emitting layer 113c_2 thinner than the light-emitting layers of the other two light-emitting devices.

[0267] The second electron-transporting layer 114c_2 is a layer containing an organic compound having a triazine ring. The first layer 161c is a layer containing an organic compound having a phenanthroline ring.

[0268] The first light-emitting layer 113c_1 and the second light-emitting layer 113c_2 are preferably light-emitting layers that emit light of similar colors. The light-emitting substances contained in the first light-emitting layer 113c_1 and the second light-emitting layer 113c_2 are preferably compounds having a difference in maximum peak wavelength in their emission spectra of 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less, and it is even more preferable that the light-emitting substances contained in the first light-emitting layer 113c_1 and the second light-emitting layer 113c_2 are the same.

[0269] It is preferable that the first light-emitting layer 113a_1 and the first light-emitting layer 113c_1 are separated, and the second light-emitting layer 113a_2 and the second light-emitting layer 113c_2 are separated. It is preferable that the emission colors of the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are different from the emission colors of the first light-emitting layer 113c_1 and the second light-emitting layer 113c_2. It is preferable that the light-emitting substance contained in the first light-emitting layer 113a_1 is different from the light-emitting substance contained in the first light-emitting layer 113c_1, and that the light-emitting substance contained in the second light-emitting layer 113a_2 is different from the light-emitting substance contained in the second light-emitting layer 113c_2.

[0270] In the example shown, the hole injection layer 111a and the hole injection layer 111c, the first hole transport layer 112a_1 and the first hole transport layer 112c_1, the first electron transport layer 114a_1 and the first electron transport layer 114c_1, the intermediate layer 160a and the intermediate layer 160c (the second layer 162a and the second layer 162c, the third layer 163a and the third layer 163c, and the first layer 161a and the first layer 161c), the second hole transport layer 112a_2 and the second hole transport layer 112c_2 are independently separated in the light-emitting device 130a and the light-emitting device 130c, while the second electron transport layer 114a_2 and the second electron transport layer 114c_2 are continuous layers. In this way, one light-emitting device may include both continuous layers and separate layers. This allows a light-emitting device or a display device with a good balance between productivity and characteristics to be manufactured. In particular, the second electron-transporting layer 114a_2 and the second electron-transporting layer 114c_2 are preferably formed as a continuous layer, because this allows both the light-emitting device 130a and the light-emitting device 130c to have good characteristics.

[0271] A light-emitting device of one embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is a schematic diagram of a light-emitting device 130a and a light-emitting device 130b, which are two adjacent light-emitting devices formed over the same insulating surface and which are included in a light-emitting device, and which are modifications of the light-emitting devices described with reference to Figs.

[0272] The light-emitting device 130a is located on an insulating layer 175 and includes a first electrode 101a including an anode, a second electrode 102 including a cathode, and an organic compound layer 103a. The organic compound layer 103a is located between the first electrode 101a and the second electrode 102. The organic compound layer 103a has a configuration in which a first light-emitting unit 501a and a second light-emitting unit 502a are stacked with an intermediate layer 160a sandwiched therebetween.

[0273] The first light-emitting unit 501a includes a first hole-transport layer 112a_1 (hole-transport layer 112a_1a and hole-transport layer 112a_1b), a first light-emitting layer 113a_1, and a first electron-transport layer 114a_1. The intermediate layer 160a includes a first layer 161a and a second layer 162a. The second light-emitting unit 502a includes a second hole-transport layer 112a_2 (hole-transport layer 112a_2a and hole-transport layer 112a_2b), a second light-emitting layer 113a_2, a second electron-transport layer 114a_2, and an electron-injection layer 115. Therefore, it can be said that the intermediate layer 160a is located between the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2.

[0274] In the light-emitting device 130a, the first light-emitting unit 501a preferably includes a hole-injection layer 111a. The intermediate layer 160a may include a third layer 163a between the first layer 161a and the second layer 162a. When the anode-side surface of the light-emitting unit is in contact with the intermediate layer 160a, as in the case of the second light-emitting unit 502a, the second layer 162a of the intermediate layer 160a located on the cathode side can also serve as the hole-injection layer for the second light-emitting unit 502a. Therefore, the hole-injection layer 111 may not be provided in the light-emitting unit. In other words, the hole-injection layer 111 may be provided as needed to achieve the desired performance of the light-emitting device.

[0275] Here, the light-emitting device 130b may have a different structure from the light-emitting device 130a. For example, the light-emitting device 130b shown in FIG. 5 has a different structure from the light-emitting device 130a in the first hole-transport layer 112a_1 and the second hole-transport layer 112a_2. When different light-emitting materials are used for the light-emitting layers of the light-emitting device 130a and the light-emitting device 130b, it is preferable to create an appropriate layer structure according to each light-emitting material. By creating a structure that optimizes the characteristics for each light-emitting device, the characteristics of the light-emitting device as a whole can be improved.

[0276] The light-emitting device 130b is located on the insulating layer 175 and includes a first electrode 101b including an anode, a second electrode 102 including a cathode, and an organic compound layer 103b. The organic compound layer 103b is located between the first electrode 101b and the second electrode 102. The organic compound layer 103b has a configuration in which a first light-emitting unit 501b and a second light-emitting unit 502b are stacked with an intermediate layer 160b sandwiched therebetween.

[0277] The first light-emitting unit 501b includes a first light-emitting layer 113b_1. The intermediate layer 160b includes a first layer 161b and a second layer 162b. The second light-emitting unit 502b includes a second light-emitting layer 113b_2 and an electron-injection layer 115. It can be said that the intermediate layer 160b is located between the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2.

[0278] In the light-emitting device 130b, the first light-emitting unit 501b preferably includes a hole-injection layer 111b, a first hole-transport layer 112b_1, and a first electron-transport layer 114b_1 in addition to the first light-emitting layer 113b_1. The second light-emitting unit 502b preferably includes a second hole-transport layer 112b_2 and a second electron-transport layer 114b_2 in addition to the second light-emitting layer 113b_2 and the electron-injection layer 115. The intermediate layer 160b can include a third layer 163b between the first layer 161b and the second layer 162b. In addition, when the anode-side surface of the light-emitting unit is in contact with the intermediate layer 160b, as in the second light-emitting unit 502b, the second layer 162b of the intermediate layer 160b located on the cathode side can also serve as the hole-injection layer for the second light-emitting unit 502b, and therefore the light-emitting unit may not be provided with the hole-injection layer 111. In other words, the hole-injection layer 111 may be provided as necessary for the desired performance of the light-emitting device.

[0279] Note that the light-emitting device according to one embodiment of the present invention does not necessarily need to include a light-emitting device having the structure shown in the light-emitting device 130b, and may include a plurality of light-emitting devices having the structure shown in the light-emitting device 130a. When the light-emitting devices have the same structure, the manufacturing apparatus can be prevented from becoming complicated.

[0280] Although Figure 5 shows an example in which each organic compound layer contains two light-emitting units, one embodiment of the present invention is not limited to this. Each organic compound layer may contain three or more light-emitting units. By stacking multiple light-emitting units between a pair of electrodes with an intermediate layer sandwiched therebetween, a highly reliable light-emitting device can be realized, which can emit light with high luminance while maintaining a low current density. Furthermore, a light-emitting device with low power consumption can be realized.

[0281] Furthermore, the light-emitting device 130, the light-emitting device 130a, or the light-emitting device 130b may be a light-emitting device manufactured using, for example, a lithography method. That is, the light-emitting device 130, the light-emitting device 130a, and the light-emitting device 130b can each be manufactured by processing a part of the organic compound layer using a lithography method. In the case of a light-emitting device manufactured using a lithography method, at least the first light-emitting layer 113_1 and the second light-emitting layer 113_2 and the organic compound layer provided closer to the first electrode 101 than the first light-emitting layer 113_1 and the second light-emitting layer 113_2 are processed simultaneously, and therefore, their edges are aligned or approximately aligned in the vertical direction.

[0282] The light-emitting device of the present invention having the structure shown in Figure 5 can be a light-emitting device with high current efficiency, low energy loss, and excellent characteristics. A display device according to one embodiment of the present invention using such a light-emitting device can be a display device with low power consumption, high reliability, and high luminance, and thus has excellent visibility. This embodiment can be freely combined with other embodiments.

[0283] The configuration shown in Fig. 5 has a particularly remarkable effect when used in a color-coded tandem light-emitting device according to one embodiment of the present application. As will be described later, a color-coded tandem light-emitting device has different layer structures for the red, green, and blue light-emitting devices, and these are stacked, resulting in a large number of materials being used or the amount of materials being used. Therefore, by applying a configuration in which the same fused rings are used in multiple layers, a configuration in which the same fused rings are bonded at different positions, or a configuration in which fused rings that are structural isomers are used, as described above, it is possible to achieve manufacturing effects such as reducing raw material costs and simplifying synthesis steps, as well as the advantage of T ｇ The use of such a material in a tandem-type light-emitting device according to one embodiment of the present application makes it possible to realize a light-emitting device suitable for mass production.

[0284] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0285] (Embodiment 2) In this embodiment, a display device manufactured using the light-emitting device described in Embodiment 1 will be described with reference to Fig. 6. Fig. 6A is a top view showing the display device, and Fig. 6B is a cross-sectional view taken along lines A-B and C-D in Fig. 6A. This display device includes a driver circuit section (source line driver circuit) 601, a pixel section 602, and a driver circuit section (gate line driver circuit) 603, all of which are shown by dotted lines, to control light emission from the light-emitting device. Also, 604 is a sealing substrate, 605 is a sealant, and the inside surrounded by the sealant 605 is a space 607.

[0286] The lead wiring 608 is wiring for transmitting signals input to the source line driver circuit 601 and the gate line driver circuit 603, and receives video signals, clock signals, start signals, reset signals, etc. from an FPC (flexible print circuit) 609, which serves as an external input terminal. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. The display device in this specification includes not only the display device itself, but also a state in which an FPC or PWB is attached to it.

[0287] Next, the cross-sectional structure will be described with reference to Fig. 6B. A driver circuit portion and a pixel portion are formed on an element substrate 610, and here, a source line driver circuit 601, which is the driver circuit portion, and one pixel in a pixel portion 602 are shown.

[0288] The element substrate 610 may be made of a substrate made of glass, quartz, organic resin, metal, alloy, semiconductor, or the like, or a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, or the like.

[0289] The structure of the transistors used in the pixels and the driver circuits is not particularly limited. For example, they may be inverted staggered transistors or staggered transistors. Furthermore, they may be top-gate or bottom-gate transistors. The semiconductor material used for the transistors is not particularly limited, and examples thereof include silicon, germanium, silicon carbide, and gallium nitride. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In—Ga—Zn-based metal oxide, may be used.

[0290] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0291] Here, it is preferable to use an oxide semiconductor for the transistors provided in the pixel and the driver circuit, as well as for semiconductor devices such as transistors used in touch sensors, which will be described later. In particular, it is preferable to use an oxide semiconductor having a wider band gap than silicon. By using an oxide semiconductor having a wider band gap than silicon, the current in the off state of the transistor can be reduced.

[0292] The oxide semiconductor preferably contains at least indium (In) or zinc (Zn), and more preferably contains an oxide represented by In-M-Zn-based oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0293] In particular, it is preferable to use, as the semiconductor layer, an oxide semiconductor film which has a plurality of crystal parts whose c-axes are oriented perpendicular to the surface on which the semiconductor layer is formed or the top surface of the semiconductor layer and in which no grain boundary can be found between adjacent crystal parts.

[0294] By using such a material for the semiconductor layer, fluctuations in electrical characteristics are suppressed, and a highly reliable transistor can be realized.

[0295] Furthermore, a transistor having the above-described semiconductor layer can retain charge accumulated in a capacitor through the transistor for a long period of time due to its low off-state current. By applying such a transistor to a pixel, it is possible to stop a driver circuit while maintaining the gray level of each pixel. As a result, an electronic device with extremely low power consumption can be realized.

[0296] For example, to stabilize the characteristics of a transistor, it is preferable to provide a base film. The base film can be formed as a single layer or a stacked layer using an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a silicon nitride oxide film. The base film can be formed by a sputtering method, a CVD (Chemical Vapor Deposition) method (such as a plasma CVD method, a thermal CVD method, or a MOCVD (Metal Organic CVD) method), an ALD (Atomic Layer Deposition) method, a coating method, a printing method, or the like. Note that the base film need not be provided if it is not necessary.

[0297] Note that the FET 623 represents one of the transistors formed in the source line driver circuit 601. The driver circuit may be formed of a CMOS circuit, a PMOS circuit, or an NMOS circuit. Although this embodiment shows a driver-integrated type in which the driver circuit is formed on a substrate, this is not necessarily required, and the driver circuit may also be formed externally rather than on the substrate.

[0298] Furthermore, the pixel portion 602 is formed by a plurality of pixels including a switching FET 611, a current control FET 612, and a first electrode 613 electrically connected to the drain of the FET, but is not limited to this, and may be a pixel combining three or more FETs and a capacitance element.

[0299] An insulator 614 is formed to cover an end portion of the first electrode 613. Here, the insulator 614 can be formed by using a positive photosensitive acrylic resin film.

[0300] Furthermore, in order to improve the coverage of organic compound layers and the like to be formed later, a curved surface having a curvature is formed at the upper or lower end of the insulator 614. For example, when a positive photosensitive acrylic resin is used as the material for the insulator 614, it is preferable to provide a curved surface having a curvature radius (0.2 μm to 3 μm) only at the upper end of the insulator 614. Furthermore, either a negative photosensitive resin or a positive photosensitive resin can be used as the insulator 614.

[0301] Note that a light-emitting device is formed with the first electrode 613, the organic compound layer 616, and the second electrode 617. The light-emitting device is the light-emitting device described in Embodiment 1. Note that a pixel portion is formed with a plurality of light-emitting devices, but the display device in this embodiment may include both the light-emitting device described in Embodiment 1 and light-emitting devices having other structures.

[0302] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with a sealing material 605, a structure is formed in which a light-emitting device 618 is provided in a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The space 607 is filled with a filler, and in some cases, the space is filled with an inert gas (nitrogen, argon, etc.), or with a sealing material. A recess is formed in the sealing substrate, and by providing a desiccant therein, deterioration due to the influence of moisture can be suppressed, which is a preferable configuration.

[0303] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is also desirable that these materials are as moisture and oxygen impermeable as possible. In addition, materials that can be used for the sealing substrate 604 include glass substrates, quartz substrates, and plastic substrates made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, etc.

[0304] 6, a protective film may be provided on the second electrode 617. The protective film may be formed of an organic resin film or an inorganic insulating film. In addition, the protective film may be formed so as to cover the exposed portion of the sealing material 605.

[0305] The protective film can be made of a material that is impermeable to impurities such as water, and therefore can effectively prevent impurities such as water from diffusing from the outside to the inside.

[0306] The protective film may be made of an oxide, nitride, fluoride, sulfide, ternary compound, metal, polymer, or the like. For example, a material containing aluminum oxide, hafnium oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, indium oxide, or the like; a material containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride, or the like; a nitride containing titanium and aluminum, an oxide containing titanium and aluminum, an oxide containing aluminum and zinc, a sulfide containing manganese and zinc, a sulfide containing cerium and strontium, an oxide containing erbium and aluminum, or an oxide containing yttrium and zirconium, or the like.

[0307] The protective film is preferably formed using a film formation method that provides good step coverage. One such method is atomic layer deposition (ALD). It is preferable to use a material that can be formed using the ALD method for the protective film. By using the ALD method, it is possible to form a dense protective film with reduced defects such as cracks and pinholes, or with a uniform thickness. Furthermore, it is possible to reduce damage to the workpiece when forming the protective film.

[0308] For example, by forming a protective film using the ALD method, it is possible to form a uniform protective film with few defects on surfaces having complex uneven shapes, including the top, side, and back surfaces of the touch panel.

[0309] In this manner, a display device manufactured using the light-emitting device described in Embodiment Mode 1 can be obtained.

[0310] The display device in this embodiment mode uses the light-emitting device described in Embodiment 1, and therefore, a display device with favorable characteristics can be obtained. Specifically, the light-emitting device described in Embodiment 1 has high emission efficiency, and therefore, a display device with low power consumption can be obtained. Furthermore, the light-emitting device described in Embodiment 1 has favorable reliability, and therefore, a display device with favorable reliability can be obtained. In addition, the light-emitting device described in Embodiment 1 can be a light-emitting device with favorable chromaticity and color purity, and therefore, a display device with favorable display quality can be obtained.

[0311] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0312] 7A and 7B, a display device is formed by forming a plurality of light-emitting devices 130 over an insulating layer 175. In this embodiment, a display device according to one embodiment of the present invention will be described in detail.

[0313] The display device 100 has a pixel section 177 in which a plurality of pixels 178 are arranged in a matrix. The pixel 178 has a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0314] In this specification and the like, when describing matters common to, for example, the subpixels 110R, 110G, and 110B, they may be referred to as the subpixels 110. When describing matters common to other components distinguished by alphabets, they may also be described using symbols without the alphabets.

[0315] The sub-pixel 110R emits red light, the sub-pixel 110G emits green light, and the sub-pixel 110B emits blue light. This allows an image to be displayed in the pixel unit 177. Note that in this embodiment, sub-pixels of three colors, red (R), green (G), and blue (B), are described as an example, but combinations of sub-pixels of other colors may also be used. The number of sub-pixels is not limited to three, and may be four or more. Examples of four sub-pixels include sub-pixels of four colors, R, G, B, and white (W); sub-pixels of four colors, R, G, B, and yellow (Y); and sub-pixels of R, G, B, and infrared (IR).

[0316] In this specification, the row direction may be referred to as the X direction, and the column direction may be referred to as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly.

[0317] 7A shows an example in which subpixels of different colors are arranged side by side in the X direction, and subpixels of the same color are arranged side by side in the Y direction. Note that subpixels of different colors may also be arranged side by side in the Y direction, and subpixels of the same color may also be arranged side by side in the X direction.

[0318] A connection portion 140 and a region 141 may be provided outside the pixel portion 177. The region 141 is provided between the pixel portion 177 and the connection portion 140. The organic compound layer 103 is provided in the region 141. In addition, the connection portion 140 is provided with a conductive layer 151C.

[0319] 7A shows an example in which the region 141 and the connection portion 140 are located on the right side of the pixel portion 177, but the positions of the region 141 and the connection portion 140 are not particularly limited. The region 141 and the connection portion 140 may be singular or plural.

[0320] Fig. 7B is an example of a cross-sectional view taken along dashed line A1-A2 in Fig. 7A. As shown in Fig. 7B, display device 100 has insulating layer 171, conductive layer 172 on insulating layer 171, insulating layer 173 on insulating layer 171 and on conductive layer 172, insulating layer 174 on insulating layer 173, and insulating layer 175 on insulating layer 174. Insulating layer 171 is provided on a substrate (not shown). Insulating layer 175, insulating layer 174, and insulating layer 173 have openings that reach conductive layer 172, and plugs 176 are provided to fill the openings.

[0321] In the pixel section 177, the light-emitting device 130 is provided on the insulating layer 175 and the plug 176. A protective layer 145 is provided to cover the light-emitting device 130. The substrate 120 is bonded to the protective layer 145 by a resin layer 122. Preferably, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are provided between adjacent light-emitting devices 130.

[0322] 7B shows multiple cross sections of the inorganic insulating layer 125 and the insulating layer 127, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are each connected to one another when the display device 100 is viewed from above. In other words, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are insulating layers having openings on the first electrodes.

[0323] 7B shows light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B. Light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B emit light of different colors. For example, light-emitting device 130R can emit red light, light-emitting device 130G can emit green light, and light-emitting device 130B can emit blue light. Light-emitting device 130R, light-emitting device 130G, or light-emitting device 130B may also emit other visible light or infrared light.

[0324] The display device of one embodiment of the present invention can be, for example, a top-emission type in which light is emitted in a direction opposite to a substrate on which a light-emitting device is formed. Note that the display device of one embodiment of the present invention may also be a bottom-emission type.

[0325] The light-emitting device 130R has the same configuration as that described in Embodiment 1. It includes a first electrode (pixel electrode) composed of a conductive layer 151R and a conductive layer 152R, an organic compound layer 103R on the first electrode, a common layer 104 on the organic compound layer 103R, and a common electrode 155 on the common layer 104. The common electrode 155 corresponds to the second electrode 102 in Embodiments 1 and 2. The common layer 104 may or may not be provided, but its provision is preferable because it reduces damage to the organic compound layer 103R during processing. When the common layer 104 is provided, it is preferable that the common layer 104 be an electron injection layer. When the common layer 104 is provided, the stacked structure of the organic compound layer 103R and the common layer 104 corresponds to the organic compound layer 103.

[0326] The light-emitting device 130G has the same configuration as that described in Embodiment 1. It includes a first electrode (pixel electrode) including a conductive layer 151G and a conductive layer 152G, an organic compound layer 103G on the first electrode, a common layer 104 on the organic compound layer 103G, and a common electrode 155 on the common layer 104. The common electrode 155 corresponds to the second electrode 102 in Embodiments 1 and 2. The common layer 104 may or may not be provided, but its provision is preferable because it can reduce damage to the organic compound layer 103G during processing. When the common layer 104 is provided, it is preferable that the common layer 104 be an electron injection layer. When the common layer 104 is provided, the stacked structure of the organic compound layer 103G and the common layer 104 corresponds to the organic compound layer 103.

[0327] The light-emitting device 130B has the same configuration as that described in Embodiment 1. It includes a first electrode (pixel electrode) including a conductive layer 151B and a conductive layer 152B, an organic compound layer 103B on the first electrode, a common layer 104 on the organic compound layer 103B, and a common electrode 155 on the common layer 104. The common electrode 155 corresponds to the second electrode 102 in Embodiments 1 and 2. The common layer 104 may or may not be provided, but its provision is preferable because it can reduce damage to the organic compound layer 103B during processing. When the common layer 104 is provided, it is preferable that the common layer 104 be an electron injection layer. When the common layer 104 is provided, the stacked structure of the organic compound layer 103B and the common layer 104 corresponds to the organic compound layer 103.

[0328] One of the pixel electrode and the common electrode of the light-emitting device functions as an anode and the other functions as a cathode. In the following description, unless otherwise specified, the pixel electrode functions as an anode and the common electrode functions as a cathode.

[0329] The organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are independent island-shaped layers for each light-emitting device or for each emitted color. By providing the organic compound layer 103 in an island shape for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in a high-resolution display device. This makes it possible to prevent crosstalk and realize a display device with extremely high contrast. In particular, a display device with high current efficiency at low brightness can be realized.

[0330] The island-shaped organic compound layer 103 is formed by depositing an EL film and processing the EL film using a lithography method.

[0331] In the display device of one embodiment of the present invention, the first electrode (pixel electrode) of the light-emitting device preferably has a stacked structure. For example, in the example shown in FIG. 7B , the first electrode of the light-emitting device 130 has a stacked structure of a conductive layer 151 (conductive layer 151R, conductive layer 151G, and conductive layer 151B) and a conductive layer 152 (conductive layer 152R, conductive layer 152G, and conductive layer 152B). For example, when the display device 100 is a top-emission type and the pixel electrode of the light-emitting device 130 functions as an anode, the conductive layer 151 is preferably a layer with high reflectivity for visible light, and the conductive layer 152 is preferably a layer that is transparent to visible light and has a high work function. When the display device 100 is a top-emission type, the higher the reflectivity of the pixel electrode for visible light, the higher the extraction efficiency of light emitted from the organic compound layer 103. When the pixel electrode functions as an anode, the higher the work function of the pixel electrode, the easier it is to inject holes into the organic compound layer 103. As described above, by forming the pixel electrode of the light-emitting device 130 into a stacked structure of the conductive layer 151 having a high reflectivity for visible light and the conductive layer 152 having a high work function, the light-emitting device 130 can be made into a light-emitting device with high light extraction efficiency and low driving voltage.

[0332] When the conductive layer 151 is a layer having high reflectivity to visible light, the reflectivity of the conductive layer 151 to visible light is preferably, for example, 40% to 100%, or 70% to 100%. When the conductive layer 152 is an electrode that is transparent to visible light, the transmittance of the conductive layer 152 to visible light is preferably, for example, 40% or more.

[0333] For example, a metal material can be used as the conductive layer 151. Specifically, 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 containing appropriate combinations of these metals, can also be used.

[0334] An oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used for the conductive layer 152. For example, it is preferable to use a conductive oxide containing one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. In particular, indium tin oxide containing silicon has a large work function, for example, a work function of 4.0 eV or more, and therefore can be suitably used for the conductive layer 152.

[0335] For example, when a microcavity structure is applied to the light-emitting device 130, the conductive layer 151 can be made of silver, which is a material with high reflectivity for visible light, or an alloy containing silver, to suitably increase the light extraction efficiency of the display device 100.

[0336] Furthermore, when the conductive layer 152 has a layered structure, by making the layered structure have different reflectivities for visible light (for example, reflectivities for light of a predetermined wavelength in the range of 400 nm or more and less than 750 nm), it is possible to form a microcavity structure in combination with the conductive layer 151.

[0337] As described above, the characteristics of the display device can be improved by forming the conductive layer 151 or the conductive layer 152 into a stacked structure of multiple layers. For example, the display device 100 can have high light extraction efficiency and high reliability.

[0338] Note that the conductive layer 151 can be formed by lithography. Specifically, first, a conductive film to be the conductive layer 151 is formed. Next, a resist mask is formed over the conductive film to be the conductive layer 151. After that, the conductive film in a region that does not overlap with the resist mask is removed by, for example, etching. Here, compared to when the conductive layer 151 is formed so that the side surface does not have a tapered shape, that is, so that the side surface is vertical, the conductive film is processed under conditions that make it easy for the resist mask to recede (shrink). This makes it possible to form the side surface of the conductive layer 151 into a tapered shape.

[0339] The conductive layer 152 may be processed by lithography simultaneously with the conductive layer 151. In this case, the side surface of the conductive layer 152 can also be formed into a tapered shape.

[0340] Here, if the conductive film is processed under conditions that make it easy for the resist mask to recede (shrink), the conductive film may be easily processed in the horizontal direction, which may result in higher isotropy of etching than when the conductive layer 151 is formed so that the side surfaces are vertical.

[0341] Furthermore, when the conductive layer 151 has a stacked structure of multiple layers made of different materials, the ease of processing in the horizontal direction may differ among the multiple layers. Therefore, as shown in FIG. 7B , by providing the insulating layer 156, corrosion in the conductive layer 151 can be suppressed. Therefore, the display device 100 can be manufactured by a method with a high yield. Furthermore, the occurrence of defects can be suppressed, and the display device 100 can be a highly reliable display device.

[0342] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0343] Embodiment 4 In this embodiment, a light-emitting device of one embodiment of the present invention will be described with reference to FIGS. 8A to 8G and 9A to 9I.

[0344] [Pixel Layout] In this embodiment, pixel layouts different from that shown in Fig. 7A will be mainly described. There are no particular limitations on the arrangement of sub-pixels, and various methods can be applied. Examples of sub-pixel arrangements include a stripe arrangement, an S-stripe arrangement, a matrix arrangement, a delta arrangement, a Bayer arrangement, and a pentile arrangement.

[0345] The top shape of the sub-pixels shown in the drawings in this embodiment mode corresponds to the top shape of the light-emitting region.

[0346] The top surface shape of the subpixel may be, for example, a triangle, a quadrangle (including a rectangle and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, or a circle.

[0347] Furthermore, the layout of the circuits constituting the sub-pixels is not limited to the range of the sub-pixels shown in the drawings, and may be arranged outside of the range.

[0348] An S-stripe arrangement is applied to the pixel 178 shown in Fig. 8A. The pixel 178 shown in Fig. 8A is composed of three subpixels: a subpixel 110R, a subpixel 110G, and a subpixel 110B.

[0349] 8B includes a subpixel 110R having a generally trapezoidal or triangular top surface shape with rounded corners, a subpixel 110G having a generally trapezoidal or triangular top surface shape with rounded corners, and a subpixel 110B having a generally rectangular or hexagonal top surface shape with rounded corners. Furthermore, the subpixel 110R has a larger light-emitting area than the subpixel 110G. In this manner, the shape and size of each subpixel can be determined independently. For example, the more reliable the light-emitting device, the smaller the size of the subpixel can be.

[0350] The Pentile arrangement is applied to the pixels 124a and 124b shown in Fig. 8C. Fig. 8C shows an example in which the pixel 124a having the subpixel 110R and the subpixel 110G and the pixel 124b having the subpixel 110G and the subpixel 110B are arranged alternately.

[0351] 8D to 8F are arranged in a delta configuration. Pixel 124a has two subpixels (subpixel 110R and subpixel 110G) in the top row (first row) and one subpixel (subpixel 110B) in the bottom row (second row). Pixel 124b has one subpixel (subpixel 110B) in the top row (first row) and two subpixels (subpixel 110R and subpixel 110G) in the bottom row (second row).

[0352] Figure 8D is an example in which each sub-pixel has an approximately rectangular top surface shape with rounded corners, Figure 8E is an example in which each sub-pixel has a circular top surface shape, and Figure 8F is an example in which each sub-pixel has an approximately hexagonal top surface shape with rounded corners.

[0353] In Figure 8F, each subpixel is arranged inside a densely arranged hexagonal region. When focusing on one subpixel, it is arranged so that it is surrounded by six other subpixels. Furthermore, subpixels that emit light of the same color are arranged so that they are not adjacent to each other. For example, when focusing on subpixel 110R, three subpixels 110G and three subpixels 110B are arranged alternately so as to surround it.

[0354] 8G shows an example in which subpixels of each color are arranged in a zigzag pattern. Specifically, when viewed from above, the positions of the upper sides of two subpixels aligned in the row direction (for example, subpixels 110R and 110G, or subpixels 110G and 110B) are misaligned.

[0355] 8A to 8G, it is preferable that the subpixel 110R is the subpixel R that emits red light, the subpixel 110G is the subpixel G that emits green light, and the subpixel 110B is the subpixel B that emits blue light. Note that the configuration of the subpixels is not limited to this, and the colors that the subpixels emit and their order of arrangement can be determined appropriately. For example, the subpixel 110G may be the subpixel R that emits red light, and the subpixel 110R may be the subpixel G that emits green light.

[0356] As shown in Figures 9A to 9I, a pixel can be configured to have four types of sub-pixels.

[0357] The pixel 178 shown in FIGS. 9A to 9C is arranged in a stripe pattern.

[0358] Figure 9A is an example in which each subpixel has a rectangular top surface shape, Figure 9B is an example in which each subpixel has a top surface shape that is a combination of two semicircles and a rectangle, and Figure 9C is an example in which each subpixel has an elliptical top surface shape.

[0359] The pixels 178 shown in FIGS. 9D to 9F are arranged in a matrix.

[0360] Figure 9D is an example in which each sub-pixel has a square top surface shape, Figure 9E is an example in which each sub-pixel has an approximately square top surface shape with rounded corners, and Figure 9F is an example in which each sub-pixel has a circular top surface shape.

[0361] 9G and 9H show an example in which one pixel 178 is configured in two rows and three columns.

[0362] 9G has three subpixels (subpixels 110R, 110G, and 110B) in the top row (first row) and one subpixel (subpixel 110W) in the bottom row (second row). In other words, pixel 178 has subpixel 110R in the left column (first column), subpixel 110G in the center column (second column), subpixel 110B in the right column (third column), and subpixels 110W across these three columns.

[0363] The pixel 178 shown in FIG. 9H has three subpixels (subpixels 110R, 110G, and 110B) in the top row (first row) and three subpixels 110W in the bottom row (second row). In other words, the pixel 178 has subpixels 110R and 110W in the left column (first column), subpixels 110G and 110W in the center column (second column), and subpixels 110B and 110W in the right column (third column). By aligning the subpixels in the top and bottom rows as shown in FIG. 9H , it becomes possible to efficiently remove dust that may occur during the manufacturing process. Therefore, a light-emitting device with high display quality can be provided.

[0364] In the pixel 178 shown in FIGS. 9G and 9H, the subpixels 110R, 110G, and 110B are laid out in a stripe arrangement, which can improve the display quality.

[0365] FIG. 9I shows an example in which one pixel 178 is configured in three rows and two columns.

[0366] 9I has subpixel 110R in the top row (first row), subpixel 110G in the middle row (second row), subpixel 110B across rows 1 and 2, and one subpixel (subpixel 110W) in the bottom row (third row). In other words, pixel 178 has subpixel 110R and subpixel 110G in the left column (first column), subpixel 110B in the right column (second column), and subpixel 110W across these two columns.

[0367] In the pixel 178 shown in FIG. 9I, the layout of the subpixels 110R, 110G, and 110B is a so-called S-stripe arrangement, which can improve the display quality.

[0368] 9A to 9I is composed of four subpixels: subpixel 110R, subpixel 110G, subpixel 110B, and subpixel 110W. For example, subpixel 110R can be a subpixel that emits red light, subpixel 110G can be a subpixel that emits green light, subpixel 110B can be a subpixel that emits blue light, and subpixel 110W can be a subpixel that emits white light. Note that at least one of subpixels 110R, subpixel 110G, subpixel 110B, and subpixel 110W may be a subpixel that emits cyan light, magenta light, yellow light, or near-infrared light.

[0369] As described above, in the light-emitting device of one embodiment of the present invention, various layouts can be applied to pixels each including a subpixel having a light-emitting device.

[0370] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0371] Embodiment 5 In this embodiment, a display device according to one embodiment of the present invention will be described.

[0372] The display device of the present embodiment can be a high-definition display device, and can therefore be used, for example, as a display unit for a wristwatch-type or bracelet-type information terminal (wearable device), as well as a display unit for a wearable device that can be worn on the head, such as a head-mounted display (HMD) for VR, or a glasses-type device for AR.

[0373] The display device of the present embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of the present embodiment can be used in electronic devices having relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproducing devices.

[0374] 10A shows a perspective view of a display module 280. The display module 280 includes a display device 100A and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100A, and may be any of the display devices 100B to 100E2 described below.

[0375] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display portion 281. The display portion 281 is a region that displays an image in the display module 280, and is a region where light from each pixel provided in a pixel portion 284 (described later) can be viewed.

[0376] 10B is a perspective view schematically illustrating the configuration on the substrate 291 side. A circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked on the substrate 291. A terminal portion 285 for connecting to the FPC 290 is provided in a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 composed of a plurality of wirings.

[0377] The pixel portion 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of Fig. 10B. The various configurations described in the previous embodiments can be applied to the pixel 284a. Fig. 10B shows an example in which the pixel 284a has the same configuration as the pixel 178 shown in Fig. 9.

[0378] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0379] One pixel circuit 283a is a circuit that controls the driving of a plurality of elements included in one pixel 284a.

[0380] The circuit portion 282 includes a circuit for driving each pixel circuit 283 a of the pixel circuit portion 283. For example, the circuit portion 282 preferably includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like.

[0381] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit portion 282. An IC may be mounted on the FPC 290.

[0382] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are stacked below the pixel unit 284, thereby making it possible to extremely increase the aperture ratio (effective display area ratio) of the display unit 281.

[0383] Because such a display module 280 has extremely high resolution, it can be suitably used in VR devices such as HMDs or eyeglass-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display unit 281, so that even if the display unit is enlarged with the lens, the pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 280 is not limited to this, and can be suitably used in electronic devices having relatively small display units.

[0384] Display Device 100A The display device 100A shown in FIG. 11A includes a substrate 301, a light-emitting device 130R, a light-emitting device 130G, a light-emitting device 130B, a capacitor 240, and a transistor 310.

[0385] The substrate 301 corresponds to the substrate 291 in FIGS. 10A and 10B . The transistor 310 is a transistor having a channel formation region in the substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities and functions as a source or drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0386] An element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0387] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0388] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located therebetween. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as a dielectric of the capacitor 240.

[0389] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and the drain of the transistor 310 by a plug 271 buried in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0390] An insulating layer 255 is provided to cover the capacitor 240, an insulating layer 174 is provided on the insulating layer 255, and an insulating layer 175 is provided on the insulating layer 174. Light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B are provided on the insulating layer 175. An insulator is provided in the region between adjacent light-emitting devices.

[0391] An insulating layer 156R is provided to have a region overlapping with a side surface of the conductive layer 151R, an insulating layer 156G is provided to have a region overlapping with a side surface of the conductive layer 151G, and an insulating layer 156B is provided to have a region overlapping with a side surface of the conductive layer 151B. A conductive layer 152R is provided to cover the conductive layer 151R and the insulating layer 156R, a conductive layer 152G is provided to cover the conductive layer 151G and the insulating layer 156G, and a conductive layer 152B is provided to cover the conductive layer 151B and the insulating layer 156B. Furthermore, a sacrificial layer 158R is located on the organic compound layer 103R of the light-emitting device 130R, a sacrificial layer 158G is located on the organic compound layer 103G of the light-emitting device 130G, and a sacrificial layer 158B is located on the organic compound layer 103B of the light-emitting device 130B.

[0392] The conductive layer 151R, the conductive layer 151G, and the conductive layer 151B are electrically connected to one of the source and the drain of the transistor 310 by an insulating layer 243, an insulating layer 255, an insulating layer 174, a plug 256 embedded in the insulating layer 175, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. Various conductive materials can be used for the plugs.

[0393] Furthermore, a protective layer 145 is provided on the light-emitting devices 130R, 130G, and 130B via a common electrode 155. A substrate 120 is bonded to the protective layer 145 by a resin layer 122. For details of the components from the light-emitting devices 130 to the substrate 120, refer to embodiment 3. The substrate 120 corresponds to the substrate 292 in FIG. 10A .

[0394] Fig. 11B is a modified example of the display device 100A shown in Fig. 11A. The display device shown in Fig. 11B has a colored layer 146R, a colored layer 146G, and a colored layer 146B, and the light-emitting device 130 has an area where it overlaps with one of the colored layers 146R, 146G, and 146B. In the display device shown in Fig. 11B, the light-emitting device 130 can emit, for example, white light. Furthermore, for example, the colored layer 146R can transmit red light, the colored layer 146G can transmit green light, and the colored layer 146B can transmit blue light.

[0395] [Display Device 100B] FIG. 12 shows a perspective view of the display device 100B, and FIG. 13 shows a cross-sectional view of the display device 100C.

[0396] The display device 100B has a configuration in which a substrate 352 and a substrate 351 are bonded together. In Fig. 12, the substrate 352 is indicated by a dashed line.

[0397] The display device 100B includes a pixel portion 177, a connection portion 140, a circuit 356, wiring 355, and the like. Fig. 12 shows an example in which an IC 354 and an FPC 353 are mounted on the display device 100B. Therefore, the configuration shown in Fig. 12 can also be called a display module including the display device 100B, an IC (integrated circuit), and an FPC. Here, a display device in which a connector such as an FPC is attached to a substrate or a display device in which an IC is mounted on the substrate is called a display module.

[0398] The connection portion 140 is provided outside the pixel portion 177. There may be one or more connection portions 140. The connection portion 140 electrically connects the common electrode of the light-emitting device and the conductive layer, and can supply a potential to the common electrode.

[0399] The circuit 356 can be, for example, a scanning line driver circuit.

[0400] The wiring 355 has a function of supplying signals and power to the pixel portion 177 and the circuit 356. The signals and power are input to the wiring 355 from the outside via the FPC 353 or from the IC 354.

[0401] 12 shows an example in which an IC 354 is provided on a substrate 351 by a chip-on-glass (COG) method, a chip-on-film (COF) method, or the like. For example, an IC having a scanning line driver circuit or a signal line driver circuit can be used as the IC 354. Note that the display device 100B and the display module may not include an IC. Alternatively, the IC may be mounted on an FPC by a COF method, for example.

[0402] Figure 13 shows an example of a cross section of the display device 100C, where a portion of the region including the FPC 353, a portion of the circuit 356, a portion of the pixel portion 177, a portion of the connection portion 140, and a portion of the region including the end portion are cut.

[0403] [Display Device 100C] The display device 100C shown in FIG. 13 has, between a substrate 351 and a substrate 352, a transistor 201, a transistor 205, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, and a light-emitting device 130B that emits blue light, etc.

[0404] For details of the light emitting device 130R, the light emitting device 130G, and the light emitting device 130B, refer to the above-described embodiments.

[0405] Light-emitting device 130R has conductive layer 224R, conductive layer 151R on conductive layer 224R, and conductive layer 152R on conductive layer 151R. Light-emitting device 130G has conductive layer 224G, conductive layer 151G on conductive layer 224G, and conductive layer 152G on conductive layer 151G. Light-emitting device 130B has conductive layer 224B, conductive layer 151B on conductive layer 224B, and conductive layer 152B on conductive layer 151B.

[0406] The conductive layer 224R is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. An end of the conductive layer 151R is located outside an end of the conductive layer 224R. An insulating layer 156R is provided to have a region in contact with the side surface of the conductive layer 151R, and a conductive layer 152R is provided to cover the conductive layer 151R and the insulating layer 156R.

[0407] Conductive layer 224G, conductive layer 151G, conductive layer 152G, and insulating layer 156G in light-emitting device 130G, and conductive layer 224B, conductive layer 151B, conductive layer 152B, and insulating layer 156B in light-emitting device 130B are similar to conductive layer 224R, conductive layer 151R, conductive layer 152R, and insulating layer 156R in light-emitting device 130R, and therefore detailed description thereof will be omitted.

[0408] Recesses are formed in the conductive layers 224R, 224G, and 224B so as to cover the openings provided in the insulating layer 214. A layer 128 is buried in the recesses.

[0409] The layer 128 has a function of filling in recesses of the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B and planarizing the surface. Conductive layers 151R, 151G, and 151B, which are electrically connected to the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B, are provided on the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B and the layer 128. Therefore, the regions overlapping with the recesses of the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B can also be used as light-emitting regions, thereby increasing the aperture ratio of the pixel.

[0410] The layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used as appropriate for the layer 128. In particular, the layer 128 is preferably formed using an insulating material, and more preferably using an organic insulating material. For example, the organic insulating material that can be used for the insulating layer 127 described above can be used for the layer 128.

[0411] A protective layer 145 is provided on the light-emitting devices 130R, 130G, and 130B via a common electrode 155. The protective layer 145 and the substrate 352 are bonded via an adhesive layer 142. A light-shielding layer 157 is provided on the substrate 352. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light-emitting device 130. In FIG. 13 , the space between the substrates 352 and 351 is filled with the adhesive layer 142, thereby applying a solid sealing structure. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), thereby applying a hollow sealing structure. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting devices. Alternatively, the space may be filled with a resin different from the frame-shaped adhesive layer 142.

[0412] 13 shows an example in which the connection portion 140 has a conductive layer 224C obtained by processing the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive layer 151C obtained by processing the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive layer 152C obtained by processing the same conductive film as the conductive layers 152R, 152G, and 152B. Also, FIG. 13 shows an example in which an insulating layer 156C is provided so as to have a region overlapping with a side surface of the conductive layer 151C.

[0413] The display device 100C is a top-emission type. Light emitted by the light-emitting device is emitted toward the substrate 352. The substrate 352 is preferably made of a material that is highly transparent to visible light. The pixel electrode contains a material that reflects visible light, and the counter electrode (second electrode 102) and the common electrode 155 contain a material that transmits visible light.

[0414] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 351 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 is provided to cover the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0415] The insulating layers 211, 213, and 215 are each preferably formed using an inorganic insulating film.

[0416] The insulating layer 214 that functions as a planarizing layer is preferably an organic insulating layer.

[0417] The transistor 201 and the transistor 205 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a conductive layer 222a and a conductive layer 222b functioning as a source and a drain, a semiconductor layer 231, an insulating layer 213 functioning as a gate insulating layer, and a conductive layer 223 functioning as a gate.

[0418] A connection portion 204 is provided in a region of the substrate 351 where the substrate 352 does not overlap. In the connection portion 204, a source electrode or a drain electrode of the transistor 201 is electrically connected to the FPC 353 through a conductive layer 166 and a connection layer 242. The conductive layer 166 has an example of a stacked structure including a conductive film obtained by processing the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive film obtained by processing the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive film obtained by processing the same conductive film as the conductive layers 152R, 152G, and 152B. The conductive layer 166 is exposed on the top surface of the connection portion 204. This allows the connection portion 204 and the FPC 353 to be electrically connected via the connection layer 242.

[0419] It is preferable to provide a light-shielding layer 157 on the surface of the substrate 352 facing the substrate 351. The light-shielding layer 157 can be provided between adjacent light-emitting devices, on the connection section 140, on the circuit 356, etc. In addition, various optical members can be arranged on the outside of the substrate 352.

[0420] The substrate 351 and the substrate 352 can be made of the same material as can be used for the substrate 120 .

[0421] The adhesive layer 142 can be made of a material that can be used for the resin layer 122 .

[0422] The connection layer 242 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0423] [Display Device 100D] The display device 100D shown in FIG. 14 differs from the display device 100C shown in FIG. 14 mainly in that it is a bottom-emission display device.

[0424] Light emitted from the light-emitting device is emitted toward the substrate 351. A material that is highly transparent to visible light is preferably used for the substrate 351. On the other hand, the light-transmitting property of the material used for the substrate 352 does not matter.

[0425] A light-shielding layer 317 is preferably formed between the substrate 351 and the transistor 201 and between the substrate 351 and the transistor 205. In the example shown in FIG. 14, the light-shielding layer 317 is provided over the substrate 351, the insulating layer 153 is provided over the light-shielding layer 317, and the transistors 201, 205, and the like are provided over the insulating layer 153.

[0426] Light emitting device 130R includes conductive layer 112R, conductive layer 126R on conductive layer 112R, and conductive layer 129R on conductive layer 126R.

[0427] Light emitting device 130B includes conductive layer 112B, conductive layer 126B on conductive layer 112B, and conductive layer 129B on conductive layer 126B.

[0428] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are each formed using a material that is highly transparent to visible light. The second electrode 102 is preferably formed using a material that reflects visible light.

[0429] Although the light emitting device 130G is not shown in FIG. 14, the light emitting device 130G is also provided.

[0430] Although FIG. 14 and other figures show an example in which the top surface of the layer 128 has a flat portion, the shape of the layer 128 is not particularly limited.

[0431] [Display Device 100D2] The display device 100D2 shown in Fig. 15 is an example of a bottom-emission type display device that differs from the display device 100D shown in Fig. 15. The display device 100D2 differs from the display device 100D in that it has an organic resin layer 180. Note that in the figure, the reference numerals of the same components as those in Fig. 15 may be omitted, and the description in Fig. 15 can be referred to for details.

[0432] 15B shows a top view layout of a pixel 178 (pixel 178a and pixel 178b) having subpixels 110 (subpixels 110R, 110G, 110B, and 110W), and Fig. 15C shows a top view of the organic resin layer 180 in a region where the subpixels 110R and 110W of the pixel 178 are formed. Note that the distance between the light-shielding layers 317 is 110Rw in the light-emitting region of the subpixel 110R.

[0433] As shown in FIG. 15A , the organic resin layer 180 is provided on the insulating layer 214. As shown in the region surrounded by the dashed line in FIG. 15A and in FIG. 15C , the organic resin layer 180 has curved recesses 181 (recesses 181 a and 181 b) at least in the region where the subpixels are formed. Note that the recesses 181 may be provided outside the light-emitting region, such as recess 181 c. Providing recess 181 c refracts light emitted in the region overlapping with the light-shielding layer 317 or light traveling to the region overlapping with the light-shielding layer 317, allowing it to be extracted from the light-emitting region, thereby improving the light-emitting efficiency.

[0434] A plurality of recesses 181 may be formed in a matrix. Recesses 181a and 181b may be provided in contact with each other, or may have a flat surface therebetween.

[0435] 15, the recess has a hexagonal top surface shape (FIG. 15C) and a semicircular cross-sectional shape (FIG. 15A), but may have other shapes as needed. For example, the recess may have a polygonal top surface shape such as a triangle, a quadrangle (including a rectangle and a square), a pentagon, or any other polygon with rounded corners, an ellipse, or a circle.

[0436] An insulating layer containing an organic material can be used as the organic resin layer 180. For example, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin, precursors of these resins, etc. can be used as the organic resin layer 180. Alternatively, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used as the organic resin layer 180.

[0437] Furthermore, a photosensitive resin can be used as the organic resin layer 180. A photoresist can be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0438] The organic resin layer 180 may contain a material that absorbs visible light. For example, the organic resin layer 180 itself may be made of a material that absorbs visible light, or the organic resin layer 180 may contain a pigment that absorbs visible light. For example, the organic resin layer 180 may be made of a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light, or a resin that contains carbon black as a pigment and functions as a black matrix.

[0439] Further, the first electrode 101 (the first electrode 101R and the first electrode 101W) is provided on the organic resin layer 180, the organic compound layer 103 is provided on the first electrode 101, and the second electrode 102 is provided on the organic compound layer 103. Ends of the first electrode 101, the organic compound layer 103, and the second electrode 102 may be covered with an insulating layer 127.

[0440] Furthermore, the first electrode 101 formed on the organic resin layer 180 has a recess similar to that of the organic resin layer 180. Furthermore, the organic compound layer 103 formed on the first electrode 101 has a recess similar to that of the first electrode 101. Furthermore, the common layer 104 formed on the organic compound layer 103 has a recess similar to that of the organic compound layer 103. Furthermore, the common electrode 155 formed on the common layer 104 has a recess similar to that of the second electrode 102. That is, the recesses of the organic resin layer 180, the first electrode 101, the organic compound layer 103, the common layer 104, and the common electrode 155 have a structure in which they overlap one another.

[0441] In addition, a common layer 104 is provided over the organic compound layer 103 and the insulating layer 127, and a common electrode 155 is provided over the common layer 104. A protective layer 145 is provided over the common electrode 155, and is bonded to a substrate 352 via an adhesive layer 142.

[0442] Although FIG. 15 shows only the light emitting device 130R and the light emitting device 130W and does not show the light emitting device 130G and the light emitting device 130B, the light emitting device 130G and the light emitting device 130B are also provided.

[0443] The light-emitting device according to one embodiment of the present invention, which includes the organic resin layer 180 as described above, has the structure described in the above embodiment. As a result, an organic semiconductor device with low driving voltage and excellent characteristics can be provided.

[0444] [Display Device 100E] The display device 100E shown in FIG. 16 is a modification of the display device 100C shown in FIG. 13, and differs from the display device 100C mainly in that it has colored layers 146R, 146G, and 146B.

[0445] In the display device 100E, the light-emitting device 130 has an area that overlaps one of the colored layers 146R, 146G, and 146B. The colored layers 146R, 146G, and 146B can be provided on the surface of the substrate 352 facing the substrate 351. An end of the colored layer 146R, an end of the colored layer 146G, and an end of the colored layer 146B can overlap the light-shielding layer 157.

[0446] In the display device 100E, for example, the colored layer 146R transmits red light, the colored layer 146G transmits green light, and the colored layer 146B transmits blue light. Note that the display device 100E may be configured such that the colored layers 146R, 146G, and 146B are provided between the protective layer 145 and the adhesive layer 142.

[0447] 17 is a modified example of the display device 100E shown in Fig. 16, and has microlenses 182 on the colored layers 146R, 146G, and 146B. Note that in the figure, the reference numerals of the same components as those in Fig. 16 may be omitted, and the description in Fig. 16 can be referred to for details.

[0448] 17B shows a top view layout of a pixel 178 (pixels 178a and 178b) having subpixels 110 (subpixels 110R, 110G, and 110B), and Fig. 17C shows a top view of a microlens 182 in a region where the subpixels 110R, 110G, and 110B of the pixel 178 are formed. Note that the region where the common electrode 155 and the organic compound layer 103 are in contact has a width 110Gw in the light-emitting region of the subpixel 110G.

[0449] 17A has a planarization film 143 provided on a protective layer 145, and colored layers 146R, 146G, and 146B provided on the planarization film 144. The planarization film 144 is provided so as to cover the colored layers 146R, 146G, and 146B. A microlens 182 is provided on the planarization film 144.

[0450] As shown in FIG. 17C, the microlens 182 may be provided for each sub-pixel in the region where the sub-pixels are formed.

[0451] 17C, the top surface shape of the microlens 182 is shown as a hexagon, but other shapes may be used as needed. For example, the top surface shape of the microlens 182 may be a polygon such as a triangle, a quadrangle (including a rectangle and a square), a pentagon, or any of these polygons with rounded corners, an ellipse, or a circle.

[0452] The microlenses 182 can be formed using the same material as the organic resin layer 180 .

[0453] The microlens is suitable for use in a light-emitting device according to one embodiment of the present invention (such as the light-emitting device using the nitrogen-containing fused heteroaromatic ring or the color-coded tandem light-emitting device described above). The microlens can concentrate light and increase the light extraction efficiency, which, together with the effect of enhancing the microcavity effect described above, can improve the light-emitting performance of the entire display device. Furthermore, applying a protective layer 145 (see FIG. 17A ) or a sealing film on the protective layer 145 is preferable because it improves the characteristics and also improves resistance to impurities.

[0454] 17A, the effect of the microlenses can be enhanced by overlapping the area between two adjacent microlenses with the area between two adjacent light-emitting devices. It is also preferable to overlap the area where two adjacent colored layers (e.g., 132B and 132G) overlap, the area between the microlenses, and the area between the light-emitting devices. It is also preferable to overlap the insulating layer 127, the area where the colored layers overlap, the area between the microlenses, and the area between the light-emitting devices. It is also preferable to overlap each of these areas with the protective layer 145 and a sealing film on the protective layer 145. The area between the microlenses can potentially be a path for impurities to enter the light-emitting devices, so the protective layer 145 or the sealing film can prevent impurities from entering.

[0455] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0456] Embodiment 6 In this embodiment, an electronic device according to one embodiment of the present invention will be described.

[0457] The electronic devices of this embodiment include the display device of one embodiment of the present invention in their display portions. The display device of one embodiment of the present invention has high display performance and can easily achieve high definition and high resolution. Therefore, the display device of one embodiment of the present invention can be used in the display portions of various electronic devices.

[0458] Examples of electronic devices include electronic devices with relatively large screens such as television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound playback devices.

[0459] In particular, the display device of one embodiment of the present invention can have high resolution and can therefore be suitably used in electronic devices having a relatively small display area. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), and head-mounted wearable devices such as VR devices (e.g., head-mounted displays), AR glasses-type devices, and MR devices.

[0460] The electronic device of this embodiment may have a sensor (including a function to measure force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0461] An example of a wearable device that can be worn on the head will be described with reference to FIGS. 18A to 18D.

[0462] The electronic device 700A shown in FIG. 18A and the electronic device 700B shown in FIG. 18B each have a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0463] The display device of one embodiment of the present invention can be applied to the display panel 751. Therefore, the electronic device can be highly reliable.

[0464] Each of the electronic device 700A and the electronic device 700B can project an image displayed on the display panel 751 onto a display area 756 of the optical member 753. Because the optical member 753 is translucent, the user can see the image displayed in the display area superimposed on a transmitted image visible through the optical member 753.

[0465] The electronic device 700A and the electronic device 700B may be provided with a camera capable of capturing an image in front of them as an imaging unit. Furthermore, the electronic device 700A and the electronic device 700B may each be provided with an acceleration sensor such as a gyro sensor, thereby detecting the orientation of the user's head and displaying an image corresponding to that orientation in the display area 756.

[0466] The communication unit has a wireless communication device, and can supply, for example, a video signal via the wireless communication device. Note that instead of or in addition to the wireless communication device, a connector to which a cable through which a video signal and a power supply potential can be connected may be provided.

[0467] Furthermore, the electronic device 700A and the electronic device 700B are provided with batteries, which can be charged wirelessly and / or wired.

[0468] The housing 721 may be provided with a touch sensor module.

[0469] Various touch sensors can be used as the touch sensor module. For example, various types of touch sensors can be used, such as a capacitance type, a resistive film type, an infrared type, an electromagnetic induction type, a surface acoustic wave type, or an optical type. In particular, it is preferable to use a capacitance type or an optical type sensor in the touch sensor module.

[0470] The electronic device 800A shown in Figure 18C and the electronic device 800B shown in Figure 18D each have a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0471] The display device of one embodiment of the present invention can be applied to the display portion 820. Therefore, the electronic device can have high reliability.

[0472] The display unit 820 is provided inside the housing 821 at a position that can be viewed through the lens 832. In addition, by displaying different images on the pair of display units 820, it is possible to perform three-dimensional display using parallax.

[0473] It is preferable that electronic device 800A and electronic device 800B each have a mechanism that allows the left and right positions of lens 832 and display unit 820 to be adjusted so that they are optimally positioned according to the position of the user's eyes.

[0474] The mounting portion 823 allows the user to mount the electronic device 800A or the electronic device 800B on the head.

[0475] The imaging unit 825 has a function of acquiring external information. Data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used for the imaging unit 825. Furthermore, multiple cameras may be provided to support multiple angles of view, such as telephoto and wide-angle.

[0476] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone.

[0477] The electronic device 800A and the electronic device 800B may each have an input terminal to which a cable can be connected for supplying a video signal from a video output device or the like and power for charging a battery provided in the electronic device.

[0478] The electronic device of one embodiment of the present invention may have a function of wirelessly communicating with the earphone 750 .

[0479] 18B includes earphone unit 727. A portion of the wiring connecting earphone unit 727 and the control unit may be disposed inside housing 721 or attachment unit 723.

[0480] 18D includes an earphone unit 827. For example, the earphone unit 827 and the control unit 824 may be configured to be connected to each other by wire.

[0481] As described above, as electronic devices according to one embodiment of the present invention, both glasses-type devices (such as the electronic devices 700A and 700B) and goggle-type devices (such as the electronic devices 800A and 800B) are suitable.

[0482] The electronic device 6500 shown in FIG. 19A is a portable information terminal that can be used as a smartphone.

[0483] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, a light source 6508, and the like. The display portion 6502 has a touch panel function.

[0484] The display device of one embodiment of the present invention can be applied to the display portion 6502. Therefore, the electronic device can have high reliability.

[0485] FIG. 19B is a schematic cross-sectional view including the end of the housing 6501 on the microphone 6506 side.

[0486] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, an optical member 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0487] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by adhesive layers (not shown).

[0488] In a region outside the display portion 6502, a part of the display panel 6511 is folded back, and an FPC 6515 is connected to the folded back part. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0489] A light-emitting device can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted while suppressing the thickness of the electronic device. In addition, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0490] 19C shows an example of a television set. A television set 7100 has a display portion 7000 built into a housing 7171. Here, the housing 7171 is supported by a stand 7173.

[0491] The display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can have high reliability.

[0492] The television set 7100 shown in FIG. 19C can be operated using an operation switch provided on the housing 7171 and a separate remote control 7151 .

[0493] 19D shows an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214. The housing 7211 includes a display portion 7000.

[0494] The display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can have high reliability.

[0495] 19E and 19F show an example of digital signage that can be used in shop windows, showcases, and the like.

[0496] 19E includes a housing 7301, a display portion 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0497] 19F shows a digital signage 7400 attached to a cylindrical pillar 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pillar 7401.

[0498] 19E and 19F, the display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can have high reliability.

[0499] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it will attract people's attention, which can increase the advertising effectiveness of, for example, advertisements.

[0500] In particular, when the display device of one embodiment of the present invention is used for advertisements using the digital signage 7300 shown in FIG. 19E and the digital signage 7400 shown in FIG. 19F, the degree of freedom of expression can be increased by using a light-transmitting panel. For example, a light-transmitting display device can be manufactured by using wiring and a support member using a conductive film that transmits visible light and adjusting the distance between pixel electrodes. Furthermore, when the pillar 7401 is made of tempered glass or the like, the display device can also be used as a showcase.

[0501] In addition to the wiring and support member using the conductive film that transmits visible light, the tandem light-emitting device according to one embodiment of the present invention can increase the luminance per pixel. That is, even if the aperture ratio of the display device is reduced, a good display can be achieved, and therefore, the light transmittance in the display portion of ...

Claims

1. A light-emitting device having a first electrode, a second electrode, an intermediate layer, a first light-emitting layer, and a second light-emitting layer, the intermediate layer is located between the first electrode and the second electrode; the first light-emitting layer is located between the first electrode and the intermediate layer, the second light-emitting layer is located between the intermediate layer and the second electrode, the first light-emitting layer includes a first light-emitting material and a second light-emitting material; the first luminescent material is a fluorescent luminescent material; the second luminescent material is a phosphorescent luminescent material or a TADF material; a maximum peak wavelength in the emission spectrum of the first luminescent material is longer than a maximum peak wavelength in the emission spectrum of the second luminescent material; the second light-emitting layer comprises a third light-emitting material; the third luminescent material is a fluorescent luminescent material; a difference between a maximum peak wavelength in an emission spectrum of the first luminescent material and a maximum peak wavelength in an emission spectrum of the third luminescent material is 30 nm or less; a light-emitting device, wherein the first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of a light-emitting layer of at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device; 　 1. A light-emitting device having a first electrode, a second electrode, an intermediate layer, a first light-emitting layer, and a second light-emitting layer, the intermediate layer is located between the first electrode and the second electrode; the first light-emitting layer is located between the first electrode and the intermediate layer, the second light-emitting layer is located between the intermediate layer and the second electrode, the first light-emitting layer includes a first light-emitting material and a second light-emitting material; the first luminescent material is a fluorescent luminescent material; the second luminescent material is a phosphorescent luminescent material or a TADF material; an emission edge on the short wavelength side in the emission spectrum of the first luminescent material is longer in wavelength than an emission edge on the short wavelength side in the emission spectrum of the second luminescent material; the second light-emitting layer comprises a third light-emitting material; the third luminescent material is a fluorescent luminescent material; a difference between a maximum peak wavelength in an emission spectrum of the first luminescent material and a maximum peak wavelength in an emission spectrum of the third luminescent material is 30 nm or less; a light-emitting device, wherein the first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of a light-emitting layer of at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device; 　 In claim 1, the second light-emitting layer comprises a fourth light-emitting material; the fourth emissive material is a phosphorescent emissive material or a TADF material; A light-emitting device, wherein the maximum peak wavelength in the emission spectrum of the third luminescent material is longer than the maximum peak wavelength in the emission spectrum of the fourth luminescent material. 　 In claim 2, the second light-emitting layer comprises a fourth light-emitting material; the fourth emissive material is a phosphorescent emissive material or a TADF material; a light-emitting device, wherein the emission edge on the short wavelength side in the emission spectrum of the third light-emitting substance is longer in wavelength than the emission edge on the short wavelength side in the emission spectrum of the fourth light-emitting substance; 　 In claim 3 or claim 4, an absorption edge on a longer wavelength side in the absorption spectrum of the first luminescent material is longer in wavelength than an emission edge on a shorter wavelength side in the emission spectrum of the second luminescent material; A light-emitting device, wherein the absorption edge on the long wavelength side in the absorption spectrum of the third light-emitting substance is longer in wavelength than the emission edge on the short wavelength side in the emission spectrum of the fourth light-emitting substance. 　 In claim 5, the first light-emitting layer includes a first compound and a second compound; the second light-emitting layer includes a third compound and a fourth compound; the first compound and the third compound each have a π-electron-deficient heteroaromatic ring, The light-emitting device, wherein the second compound and the fourth compound each have at least one of a π-electron rich heteroaromatic ring and a triarylamine skeleton. 　 In claim 6, the first compound and the second compound are a combination that forms a first exciplex, an emission spectrum of the first exciplex and an emission spectrum of the second luminescent material overlap with each other; the third compound and the fourth compound are a combination that forms a second exciplex, a light-emitting device in which the emission spectrum of the second exciplex and the emission spectrum of the fourth emissive material overlap; 　 In claim 7, a difference between an emission edge on a short wavelength side in the phosphorescence spectrum of the first compound and an emission edge on a short wavelength side in the phosphorescence spectrum of the second compound is 30 nm or less; a difference between the short wavelength emission edge in the phosphorescence spectrum of the third compound and the short wavelength emission edge in the phosphorescence spectrum of the fourth compound being 30 nm or less; 　 In any one of claims 1 to 4, a first electron transport layer and a second electron transport layer; the first electron transport layer is located between the first light-emitting layer and the intermediate layer; the second electron transport layer is located between the second light-emitting layer and the second electrode; the second electron transport layer comprises a fifth compound; the fifth compound has a triazine ring, the intermediate layer has a mixed layer of the sixth compound and lithium or a lithium compound, The sixth compound has a phenanthroline ring. 　 In any one of claims 1 to 4, the first luminescent substance and the third luminescent substance are fluorescent luminescent substances each having a luminophore and a protecting group; the luminophore is a fused aromatic ring or a fused heteroaromatic ring; The protecting group has any one of an alkyl group having from 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to 10 carbon atoms, and a trialkylsilyl group having from 3 to 10 carbon atoms. 　 In any one of claims 1 to 4, a first hole transport layer and a second hole transport layer; the first hole transport layer is located between the first electrode and the first light-emitting layer; the second hole transport layer is located between the intermediate layer and the second light-emitting layer, a light-emitting device, wherein at least one of the first hole transport layer and the second hole transport layer includes an organic compound having a π-electron-rich heteroaromatic ring and not having a triarylamine skeleton; 　 In any one of claims 1 to 4, a first hole transport layer and a second hole transport layer; the first hole transport layer is located between the first electrode and the first light-emitting layer; the second hole transport layer is located between the intermediate layer and the second light-emitting layer, the first hole transport layer has a first layer and a second layer, the first layer is in contact with the first light-emitting layer, the first layer contains an organic compound having a π-electron-rich heteroaromatic ring and not having a triarylamine skeleton, The second layer comprises an organic compound having a triarylamine skeleton. 　 A display device having a light-emitting device A and a light-emitting device B, The light-emitting device B has a different emission color from the light-emitting device A, The light-emitting device A has a first electrode A, a second electrode A, an intermediate layer A, a first light-emitting layer A, a second light-emitting layer A, a first hole-transporting layer A, and a second hole-transporting layer A; the intermediate layer A is located between the first electrode A and the second electrode A, the first light-emitting layer A is located between the first electrode A and the intermediate layer A, the second light-emitting layer A is located between the intermediate layer A and the second electrode A, the first hole transport layer A is located between the first electrode A and the first light-emitting layer A, the second hole transport layer A is located between the intermediate layer A and the second light-emitting layer A, the first light-emitting layer A includes a first light-emitting material and a second light-emitting material, the first luminescent material is a fluorescent luminescent material; the second luminescent material is a phosphorescent luminescent material or a TADF material; a maximum peak wavelength in the emission spectrum of the first luminescent material is longer than a maximum peak wavelength in the emission spectrum of the second luminescent material; the second light-emitting layer A contains a third light-emitting material, the third luminescent material is a fluorescent luminescent material; a difference between a maximum peak wavelength in an emission spectrum of the first luminescent material and a maximum peak wavelength in an emission spectrum of the third luminescent material is 30 nm or less; the light-emitting device B has a first electrode B, a second electrode B, an intermediate layer B, a first light-emitting layer B, a second light-emitting layer B, a first hole-transporting layer B, and a second hole-transporting layer B; the intermediate layer B is located between the first electrode B and the second electrode B, the first light-emitting layer B is located between the first electrode B and the intermediate layer B, the second light-emitting layer B is located between the intermediate layer B and the second electrode B, the first hole transport layer B is located between the first electrode B and the first light-emitting layer B, the second hole transport layer B is located between the intermediate layer B and the second light-emitting layer B, the first light-emitting layer B contains a fourth light-emitting material, the fourth luminescent material is a phosphorescent luminescent material; the second light-emitting layer B contains a fifth light-emitting material, the fifth luminescent material is a phosphorescent luminescent material; a difference between a maximum peak wavelength in the emission spectrum of the fourth luminescent material and a maximum peak wavelength in the emission spectrum of the fifth luminescent material is 30 nm or less; a first light-emitting layer A and a second light-emitting layer A each having a light-emitting layer that emits light in a color gamut different from that of the first light-emitting layer B and the second light-emitting layer B; 　 A display device having a light-emitting device A and a light-emitting device B, The light-emitting device B has a different emission color from the light-emitting device A, The light-emitting device A has a first electrode A, a second electrode A, an intermediate layer A, a first light-emitting layer A, a second light-emitting layer A, a first hole-transporting layer A, and a second hole-transporting layer A; the intermediate layer A is located between the first electrode A and the second electrode A, the first light-emitting layer A is located between the first electrode A and the intermediate layer A, the second light-emitting layer A is located between the intermediate layer A and the second electrode A, the first hole transport layer A is located between the first electrode A and the first light-emitting layer A, the second hole transport layer A is located between the intermediate layer A and the second light-emitting layer A, the first light-emitting layer A includes a first light-emitting material and a second light-emitting material, the first luminescent material is a fluorescent luminescent material; the second luminescent material is a phosphorescent luminescent material or a TADF material; a maximum peak wavelength in the emission spectrum of the first luminescent material is longer than a maximum peak wavelength in the emission spectrum of the second luminescent material; the second light-emitting layer A contains a third light-emitting material, the third luminescent material is a fluorescent luminescent material; a difference between a maximum peak wavelength in an emission spectrum of the first luminescent material and a maximum peak wavelength in an emission spectrum of the third luminescent material is 30 nm or less; the light-emitting device B has a first electrode B, a second electrode B, an intermediate layer B, a first light-emitting layer B, a second light-emitting layer B, a first hole-transporting layer B, and a second hole-transporting layer B; the intermediate layer B is located between the first electrode B and the second electrode B, the first light-emitting layer B is located between the first electrode B and the intermediate layer B, the second light-emitting layer B is located between the intermediate layer B and the second electrode B, the first hole transport layer B is located between the first electrode B and the first light-emitting layer B, the second hole transport layer B is located between the intermediate layer B and the second light-emitting layer B, the first light-emitting layer B contains a fourth light-emitting material, the fourth luminescent material is a fluorescent luminescent material; the second light-emitting layer B contains a fifth light-emitting material, the fifth luminescent material is a fluorescent luminescent material; a difference between a maximum peak wavelength in the emission spectrum of the fourth luminescent material and a maximum peak wavelength in the emission spectrum of the fifth luminescent material is 30 nm or less; a first light-emitting layer A and a second light-emitting layer A each having a light-emitting layer that emits light in a color gamut different from that of the first light-emitting layer B and the second light-emitting layer B;

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