Display device

Abstract

To provide a display device with reduced manufacturing cost.SOLUTION: A display device includes first to third sub-pixels that emit light of different colors. The first sub-pixel includes a first coloring layer and a first light emitting device, the second sub-pixel includes a second coloring layer and a second light emitting device, and the third sub-pixel includes a third light emitting device. The first light emitting device includes first and second light emitting layers between the pair of electrodes, and a first intermediate layer between the first and second light emitting layers. The first and second light-emitting layers each include a layer containing a blue light-emitting substance and a layer containing a red light-emitting substance. The second light emitting device includes third and fourth light-emitting layers between a pair of electrodes and a second intermediate layer between the third and fourth light-emitting layers, and the third and fourth light-emitting layers each include a layer containing the blue light-emitting substance and a layer containing the red light-emitting substance. The third light emitting device includes a fifth light-emitting layer and a sixth light-emitting layer between a pair of electrodes, a third intermediate layer between the fifth light-emitting layer and the sixth light-emitting layer. The fifth light-emitting layer and the sixth light-emitting layer each have a green light-emitting substance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a display device. Note that this 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 etc. relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specific 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, driving methods thereof, and manufacturing methods thereof. [Background technology]

[0002] Light-emitting devices (organic EL devices) that utilize electroluminescence (EL) using organic compounds are becoming more and more common. The basic structure of these light-emitting devices is a pair of electrodes sandwiching an organic compound layer (EL layer) containing a light-emitting material between them. By applying a voltage to this device, carriers are injected, and the recombination energy of these carriers is utilized to emit light from the light-emitting material.

[0003] Since such light-emitting devices are self-luminous, when used in the pixels of a display device, they offer advantages such as higher visibility and no need for backlighting compared to liquid crystals, making them suitable for use in flat panel displays. Another major advantage of display devices using such light-emitting devices is that they can be fabricated to be thin and lightweight. Another feature is their extremely fast response time.

[0004] Display devices using light-emitting devices are suitable for a variety of electronic devices, and research and development is underway to develop light-emitting devices with even better characteristics. In particular, so-called tandem light-emitting devices, in which multiple light-emitting units are stacked, have attracted attention because they achieve high light-emitting efficiency. Patent Documents 1 and 2 disclose tandem light-emitting devices using a separate coating method. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-317548 [Patent Document 2] Japanese Patent Publication No. 2023-161850 Summary of the Invention [Problem to be solved by the invention]

[0006] Tandem light-emitting devices using the separate coloring method have the problem that their manufacturing process is complicated and the number of steps increases, so when the tandem light-emitting devices using the separate coloring method are used for the pixels of a display device, there are problems such as an increase in the manufacturing cost of the display device and a decrease in manufacturing yield.

[0007] In view of the above, an object of one embodiment of the present invention is to provide a display device with a simplified manufacturing process. Another object of one embodiment of the present invention is to provide a display device with reduced manufacturing cost. Another object of one embodiment of the present invention is to provide an inexpensive display device. Another object of one embodiment of the present invention is to provide a display device with low power consumption. Another object of one embodiment of the present invention is to provide a novel display device.

[0008] 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. [Means for solving the problem]

[0009] One embodiment of the present invention has a first subpixel, a second subpixel, and a third subpixel that emit light of different colors, in which the first subpixel has a first colored layer and a first light-emitting device, the second subpixel has a second colored layer and a second light-emitting device, and the third subpixel has a third light-emitting device. The first light-emitting device has a first light-emitting layer and a second light-emitting layer between a pair of electrodes and a first intermediate layer between the first light-emitting layer and the second light-emitting layer, and the first light-emitting layer and the second light-emitting layer have a layer containing a blue light-emitting material and a layer containing a red light-emitting material, respectively. The display device has a layer containing a blue light-emitting material and a layer containing a red light-emitting material; the second light-emitting device has a third light-emitting layer and a fourth light-emitting layer between a pair of electrodes and a second intermediate layer between the third and fourth light-emitting layers, the third light-emitting layer and the fourth light-emitting layer having a layer containing a blue light-emitting material and a layer containing a red light-emitting material, respectively; the third light-emitting device has a fifth light-emitting layer and a sixth light-emitting layer between the pair of electrodes and a third intermediate layer between the fifth and sixth light-emitting layers, the fifth and sixth light-emitting layers having a green light-emitting material, respectively. It is more preferable that the blue light-emitting material is a fluorescent light-emitting material and the red light-emitting material is a phosphorescent light-emitting material. It is also more preferable that the layer containing the blue light-emitting material contains a first host material, and that the T1 levels of the first host material and the blue light-emitting material are higher than the T1 levels of the red light-emitting material.

[0010] Another embodiment of the present invention provides a pixel including a first subpixel and a second subpixel emitting light of different colors, the first subpixel having a first colored layer and a first light-emitting device, and the second subpixel having a second colored layer and a second light-emitting device. The first light-emitting device has a first light-emitting layer, a second light-emitting layer, a third light-emitting layer, a fourth light-emitting layer, and a first intermediate layer between a pair of electrodes, the first light-emitting layer being in contact with the second light-emitting layer, the third light-emitting layer being in contact with the fourth light-emitting layer, the first intermediate layer being located between the first light-emitting layer and the third light-emitting layer and also between the second light-emitting layer and the fourth light-emitting layer, and the second light-emitting device is a display device having a fifth light-emitting layer, a sixth light-emitting layer, a seventh light-emitting layer, an eighth light-emitting layer, and a second intermediate layer between a pair of electrodes, the fifth light-emitting layer being in contact with the sixth light-emitting layer, the seventh light-emitting layer being in contact with the eighth light-emitting layer, the second intermediate layer being located between the fifth and seventh light-emitting layers and also between the sixth and eighth light-emitting layers, the first and fifth light-emitting layers containing a first light-emitting substance, the second and sixth light-emitting layers containing a second light-emitting substance, the third and seventh light-emitting layers containing the first light-emitting substance, and the fourth and eighth light-emitting layers containing a second light-emitting substance. It is more preferable that the first light-emitting substance is a blue light-emitting substance, and the second light-emitting substance is a red light-emitting substance. Furthermore, it is more preferable that the emission wavelength of one of the first luminescent material and the second luminescent material is 1.18 times or more and 1.88 times or less than the emission wavelength of the other.

[0011] One embodiment of the present invention provides a pixel having a first subpixel, a second subpixel, and a third subpixel that emit light of different colors, the first subpixel having a first colored layer and a first light-emitting device, the second subpixel having a second colored layer and a second light-emitting device, and the third subpixel having a third light-emitting device. The first light-emitting device has a first light-emitting layer, a second light-emitting layer, a third light-emitting layer, a fourth light-emitting layer, and a first intermediate layer between a pair of electrodes, the first light-emitting layer being in contact with the second light-emitting layer, and the third light-emitting layer being in contact with the fourth light-emitting layer. The first intermediate layer is located between the first light-emitting layer and the third light-emitting layer and also between the second light-emitting layer and the fourth light-emitting layer. The second light-emitting device has a fifth light-emitting layer, a sixth light-emitting layer, a seventh light-emitting layer, an eighth light-emitting layer, and a fifth light-emitting layer between the pair of electrodes. a second intermediate layer, a fifth light-emitting layer in contact with the sixth light-emitting layer, and a seventh light-emitting layer in contact with the eighth light-emitting layer, the second intermediate layer being located between the fifth and seventh light-emitting layers and also between the sixth and eighth light-emitting layers; a third light-emitting device having a ninth light-emitting layer, a tenth light-emitting layer, and a third intermediate layer between a pair of electrodes, the third intermediate layer being located between the ninth and tenth light-emitting layers, the first light-emitting layer and the fifth light-emitting layer comprising a first light-emitting material, the second light-emitting layer and the sixth light-emitting layer comprising a second light-emitting material, the third light-emitting layer and the seventh light-emitting layer comprising a first light-emitting material, the fourth light-emitting layer and the eighth light-emitting layer comprising a second light-emitting material, and the ninth light-emitting layer and the tenth light-emitting layer comprising a third light-emitting material. More preferably, the first luminescent material is a blue luminescent material, the second luminescent material is a red luminescent material, and the third luminescent material is a green luminescent material.More preferably, the emission wavelength of one of the first luminescent material and the second luminescent material is 1.18 to 1.88 times the emission wavelength of the other.

[0012] One embodiment of the present invention is a display device having any of the above structures, in which the first light-emitting substance is a fluorescent light-emitting substance and the second light-emitting substance is a phosphorescent light-emitting substance.

[0013] Another embodiment of the present invention is a display device having any of the above structures, wherein the first light-emitting substance is a fluorescent light-emitting substance, the second light-emitting substance is a phosphorescent light-emitting substance, the first light-emitting layer includes a first host material, and the T1 levels of the first host material and the first light-emitting substance are higher than the T1 level of the second light-emitting substance.

[0014] Another embodiment of the present invention is a display device having any of the above structures, in which the first intermediate layer and the second intermediate layer each contain an organic compound and an alkali metal or an alkaline earth metal.

[0015] Another embodiment of the present invention is a display device having any of the above structures, in which the first intermediate layer and the second intermediate layer contain the same organic compound and the same alkali metal or alkaline earth metal. [Effects of the Invention]

[0016] According to one embodiment of the present invention, a display device with a simplified manufacturing process can be provided. According to another embodiment of the present invention, a display device with reduced manufacturing cost can be provided. According to another embodiment of the present invention, an inexpensive display device can be provided. According to another embodiment of the present invention, it is an object to provide a display device with low power consumption. According to another embodiment of the present invention, a novel display device can be provided.

[0017] 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. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1A is a top view illustrating a structure of a display device according to an embodiment, and FIG. 1B is a cross-sectional view illustrating a structure of a display device according to an embodiment. [Figure 2]2A and 2B are cross-sectional views illustrating a structure of a display device according to an embodiment. [Figure 3] FIG. 3 is an energy diagram according to the embodiment. [Figure 4] 4A and 4B are cross-sectional views illustrating the structure of a display device according to an embodiment. [Figure 5] 5A and 5B are cross-sectional views illustrating a configuration of a display device according to an embodiment. [Figure 6] 6A and 6B are cross-sectional views illustrating a structure of a display device according to an embodiment. [Figure 7] 7A to 7D are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 8] 8A to 8D are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 9] 9A to 9C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 10] 10(A) to 10(E) are diagrams illustrating a light-emitting device. [Figure 11] 11(A) and 11(B) are perspective views showing an example of a display device. [Figure 12] FIG. 12 is a cross-sectional view showing an example of a display device. [Figure 13] 13A to 13D are diagrams showing examples of electronic devices. [Figure 14] 14A to 14F are diagrams showing examples of electronic devices. [Figure 15] 15A to 15G are diagrams showing examples of electronic devices. [Figure 16] 16A to 16G are top views showing examples of pixel configurations. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and various changes in form and details are possible 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.

[0020] 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, etc.

[0021] In addition, in this specification and the like, ordinal numbers such as "first," "second," etc. are used for convenience and may not indicate the order of processes or stacking. Therefore, for example, "first" can be appropriately replaced with "second," "third," etc. in the description. Furthermore, the ordinal numbers used to identify one embodiment of the present invention may not match the ordinal numbers used in this specification and the like.

[0022] Furthermore, in this specification and the like, when describing the configuration of the invention using drawings, the same reference numerals may be used in common between different drawings.

[0023] Furthermore, in this specification and the like, the terms "film" and "layer" can be interchangeable. 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."

[0024] (Embodiment 1) In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0025] FIG. 1A shows a top view of a display device 100, which is a display device according to one embodiment of the present invention. The display device 100 includes a display portion in which a plurality of pixels 110 are arranged and a connection portion 140 outside the display portion. A plurality of subpixels are arranged in a matrix in the display portion. FIG. 1A shows two rows and six columns of subpixels, which together form two rows and two columns of pixels 110. The connection portion 140 can also be called a cathode contact portion. Although not shown, each subpixel includes a circuit for driving the subpixel. The circuit includes a transistor and is connected to a light-emitting device included in the subpixel.

[0026] The top surface shape of the subpixel shown in Figure 1(A) corresponds to the top surface shape of the light-emitting region. In this specification and the like, the top surface shape refers to the shape in a plan view, that is, the shape seen from above. Examples of the top surface shape of the subpixel include a triangle, a quadrangle (including a rectangle, a rhombus, and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, or a circle.

[0027] Furthermore, the circuit layout constituting the subpixels is not limited to the range of the subpixels shown in Fig. 1(A), and circuit components may be located outside the range. For example, some or all of the transistors included in the subpixel 50R shown in Fig. 1(A) may be located outside the range of the subpixel 50R. The transistors included in the subpixel 50R may be located within the range of the subpixel 50R, the range of the subpixel 50G, or the range of the subpixel 50B shown in Fig. 1(A), or may be located across multiple of these ranges.

[0028] 1A, the subpixels 50R, 50B, and 50G are shown with the same or approximately the same aperture ratio (which can also be referred to as the size or size of the light-emitting region), but this is not a limitation of one embodiment of the present invention. The aperture ratios of the subpixels 50R, 50B, and 50G can be determined as appropriate. The aperture ratios of the subpixels 50R, 50B, and 50G may be different from one another, or two or more of the subpixels may be the same or approximately the same.

[0029] A stripe arrangement is applied to the pixel 110 shown in Fig. 1(A). The pixel 110 shown in Fig. 1(A) is composed of three subpixels: subpixel 50R, subpixel 50B, and subpixel 50G. The subpixels 50R, 50B, and 50G each emit a different color. Examples of the emitted colors of the subpixels 50R, 50B, and 50G include red, blue, and green.

[0030] In this specification and the like, the row direction may be referred to as the X direction, the column direction as the Y direction, and the depth direction as the Z direction. Figure 1(A) shows an example in which sub-pixels of different colors are arranged side by side in the X direction, and sub-pixels of the same color are arranged side by side in the Y direction.

[0031] Fig. 1(B) shows a cross-sectional view taken along dashed line X1-X2 in Fig. 1(A). Also, Fig. 2, Fig. 4, Fig. 5, and Fig. 6 show modified examples of the cross-sectional view taken along dashed line X1-X2 in Fig. 1(A).

[0032] In the display device 100, light-emitting devices 10R, 10B, and 10G are provided on a layer 121 including transistors (not shown), and a protective layer 122 is provided to cover these light-emitting devices. A substrate 124, on which colored layers 136R and 136B are provided, is further attached by a resin layer 123. An insulating layer 125 is provided in the region between the anodes of adjacent light-emitting devices. A black matrix 137 is provided in the region between adjacent colored layers.

[0033] In the display device 100, the subpixel 50R has the light-emitting device 10R and a colored layer 136R overlapping the light-emitting device 10R, the subpixel 50B has the light-emitting device 10B and a colored layer 136B overlapping the light-emitting device 10B, and the subpixel 50G has the light-emitting device 10G. In the display device 100, the light-emitting devices 10R and 10B are light-emitting devices having similar configurations and thus emit light of the same color. However, by providing the subpixels 50R and 50B with colored layers that transmit light of different colors, the emitted colors of the subpixels 50R and 50B can be made different. Furthermore, the light-emitting device 10G has a different configuration from the light-emitting devices 10R and 10B and emits light of a different color. Therefore, the subpixel 50G can emit light of a different color from the subpixels 50R and 50B without providing a colored layer.

[0034] The display device of one embodiment of the present invention is preferably a top-emission display device that emits light in the direction opposite to the substrate on which the light-emitting device is formed.

[0035] The layer 121 may have a laminated structure in which, for example, a plurality of transistors (not shown) are provided on a substrate and an insulating layer is provided to cover these transistors. The layer 121 may have a recess in an area that does not overlap with the light-emitting device. For example, the recess may be provided in the insulating layer located on the outermost surface of the layer 121. An example of the structure of the layer 121 will be described later in the fourth embodiment.

[0036] As shown in FIG. 1(B), in the display device 100, an anode 11R, an anode 11B, and an anode 11G are provided on a layer 121, a first hole injection / transport layer 12_a is provided on the anode 11R, the anode 11B, and the anode 11G, a first light-emitting layer 13B_a is provided on the first hole injection / transport layer 12_a at a position overlapping with the anodes 11R and 11B, a second light-emitting layer 13R_a is provided on the first light-emitting layer 13B_a at a position overlapping with the anodes 11R and 11B, a first light-emitting layer 13G_a is provided on the first hole injection / transport layer 12_a at a position overlapping with the anode 11G, a first electron injection / transport layer 14_a is provided on the second light-emitting layer 13R_a and the first light-emitting layer 13G_a, and a first electron injection / transport layer 14_a is provided on the second light-emitting layer 13R_a and the first light-emitting layer 13G_a. An intermediate layer 21 is provided on the layer 14_a, a second hole injection / transport layer 12_b is provided on the intermediate layer 21, a third light-emitting layer 13B_b is provided on the second hole injection / transport layer 12_b at a position overlapping with the anodes 11R and 11B, a fourth light-emitting layer 13R_b is provided on the third light-emitting layer 13B_b at a position overlapping with the anodes 11R and 11B, a second light-emitting layer 13G_b is provided on the second hole injection / transport layer 12_b at a position overlapping with the anode 11G, a second electron injection / transport layer 14_b is provided on the fourth light-emitting layer 13R_b and the second light-emitting layer 13G_b, and a cathode 15 is formed on the second electron injection / transport layer 14_b, thereby providing tandem light-emitting devices 10R, 10B, and 10G. The first hole injection / transport layer 12_a and the second hole injection / transport layer 12_b preferably have a laminated structure, for example, a laminated structure in which a hole injection layer and a hole transport layer are laminated in this order from the anode side. The first electron injection / transport layer 14_a and the second electron injection / transport layer 14_b preferably have a laminated structure, for example, a laminated structure in which an electron transport layer and an electron injection layer are laminated in this order from the light-emitting layer side.

[0037] The first hole injection / transport layer 12_a, the second hole injection / transport layer 12_b, the intermediate layer 21, the first electron injection / transport layer 14_a, the second electron injection / transport layer 14_b, and the cathode 15 are preferably layers (hereinafter sometimes referred to as common layers) that are common to the light-emitting devices 10R, 10B, and 10G. By using these layers as common layers, the manufacturing process of the display device 100 can be simplified, thereby reducing the cost of the display device 100.

[0038] Furthermore, the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b are preferably layers formed on the light-emitting devices 10R and 10B by vacuum deposition using a metal mask. The first light-emitting layer 13G_a and the second light-emitting layer 13G_b are preferably layers formed on the light-emitting device 10G by vacuum deposition using a metal mask. However, the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b are preferably layers shared by the light-emitting devices 10R and 10B. By using these layers shared by the light-emitting devices 10R and 10B, the manufacturing process of the display device 100 can be simplified, thereby reducing the cost of the display device 100.

[0039] The light-emitting device 10R includes a first light-emitting layer 13B_a, a second light-emitting layer 13R_a, a third light-emitting layer 13B_b, a fourth light-emitting layer 13R_b, and an intermediate layer 21 between the anode 11R and the cathode 15. The intermediate layer 21 is located between the first light-emitting layer 13B_a and the third light-emitting layer 13B_b and between the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b. The first light-emitting layer 13B_a and the second light-emitting layer 13R_a are preferably in contact with each other. Alternatively, the first light-emitting layer 13B_a and the second light-emitting layer 13R_a are preferably stacked with a buffer layer interposed therebetween. Furthermore, the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b are preferably in contact with each other. Alternatively, the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b are preferably stacked with a buffer layer interposed therebetween. The light-emitting device 10R also has a first hole injection / transport layer 12_a, a first electron injection / transport layer 14_a, a second hole injection / transport layer 12_b, and a second electron injection / transport layer 14_b. The first hole injection / transport layer 12_a is located between the anode 11R and the first light-emitting layer 13B_a, and also between the anode 11R and the second light-emitting layer 13R_a; the first electron injection / transport layer 14_a is located between the first light-emitting layer 13B_a and the intermediate layer 21, and also between the second light-emitting layer 13R_a and the intermediate layer 21; the second hole injection / transport layer 12_b is located between the intermediate layer 21 and the third light-emitting layer 13B_b, and also between the intermediate layer 21 and the fourth light-emitting layer 13R_b; and the second electron injection / transport layer 14_b is located between the third light-emitting layer 13B_b and the cathode 15, and also between the fourth light-emitting layer 13R_b and the cathode 15.

[0040] The light-emitting device 10B includes a first light-emitting layer 13B_a, a second light-emitting layer 13R_a, a third light-emitting layer 13B_b, a fourth light-emitting layer 13R_b, and an intermediate layer 21 between an anode 11B and a cathode 15. The intermediate layer 21 is located between the first light-emitting layer 13B_a and the third light-emitting layer 13B_b and between the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b. The first light-emitting layer 13B_a and the second light-emitting layer 13R_a are preferably in contact with each other. Alternatively, the first light-emitting layer 13B_a and the second light-emitting layer 13R_a are preferably stacked with a buffer layer interposed therebetween. Furthermore, the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b are preferably in contact with each other. Alternatively, the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b are preferably stacked with a buffer layer interposed therebetween. The light-emitting device 10B also has a first hole injection / transport layer 12_a, a first electron injection / transport layer 14_a, a second hole injection / transport layer 12_b, and a second electron injection / transport layer 14_b. The first hole injection / transport layer 12_a is located between the anode 11B and the first light-emitting layer 13B_a, and also between the anode 11B and the second light-emitting layer 13R_a; the first electron injection / transport layer 14_a is located between the first light-emitting layer 13B_a and the intermediate layer 21, and also between the second light-emitting layer 13R_a and the intermediate layer 21; the second hole injection / transport layer 12_b is located between the intermediate layer 21 and the third light-emitting layer 13B_b, and also between the intermediate layer 21 and the fourth light-emitting layer 13R_b; and the second electron injection / transport layer 14_b is located between the third light-emitting layer 13B_b and the cathode 15, and also between the fourth light-emitting layer 13R_b and the cathode 15.

[0041] In the light-emitting devices 10R and 10B, the first light-emitting layer 13B_a and the second light-emitting layer 13R_a each contain a light-emitting material that emits light of a different color. The third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b each contain a light-emitting material that emits light of a different color. The first light-emitting layer 13B_a and the third light-emitting layer 13B_b each contain a light-emitting material that emits light of the same color. The second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b each contain a light-emitting material that emits light of the same color. The light-emitting devices 10R and 10B have the above-described combination of the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b, and thus can emit light in a color that is a mixture of the color derived from the light-emitting material contained in the first light-emitting layer 13B_a and the third light-emitting layer 13B_b and the color derived from the light-emitting material contained in the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b. In the display device 100, the colored layer 136R overlapping the light-emitting device 10R and the colored layer 136B overlapping the light-emitting device 10B transmit light of different colors, thereby making it possible to differentiate the emission colors of the sub-pixels 50R and 50B.

[0042] Furthermore, in the light-emitting devices 10R and 10B, by combining the first light-emitting layer 13B_a and the third light-emitting layer 13B_b with the same light-emitting material, and the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b with the same light-emitting material, the manufacturing of the display device 100 becomes easier, and the cost of the display device 100 can be reduced.

[0043] When a blue light-emitting material is used for the first light-emitting layer 13B_a and the third light-emitting layer 13B_b and a red light-emitting material is used for the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b, the light-emitting devices 10R and 10B can each emit magenta light, which is a mixture of blue and red. In this case, by using a material that transmits red light for the colored layer 136R overlapping the light-emitting device 10R and a material that transmits blue light for the colored layer 136B overlapping the light-emitting device 10B, the sub-pixel 50R can be a red sub-pixel and the sub-pixel 50B can be a blue sub-pixel.

[0044] As another example, when a green light-emitting material is used for the first light-emitting layer 13B_a and the third light-emitting layer 13B_b and a red light-emitting material is used for the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b, the light-emitting devices 10R and 10B can each emit yellow light, which is a mixture of green and red. In this case, by using a material that transmits red light for the colored layer 136R overlapping the light-emitting device 10R and a material that transmits green light for the colored layer 136B overlapping the light-emitting device 10B, the sub-pixel 50R can be a red sub-pixel and the sub-pixel 50B can be a green sub-pixel.

[0045] As another example, when a blue light-emitting material is used for the first light-emitting layer 13B_a and the third light-emitting layer 13B_b and a green light-emitting material is used for the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b, the light-emitting devices 10R and 10B can each emit cyan light, which is a mixture of blue and green. In this case, by using a material that transmits green light for the colored layer 136R overlapping the light-emitting device 10R and a material that transmits blue light for the colored layer 136B overlapping the light-emitting device 10B, the sub-pixel 50R can be a green sub-pixel and the sub-pixel 50B can be a blue sub-pixel.

[0046] In the light-emitting devices 10R and 10B shown in FIG. 1(B), of the first light-emitting layer 13B_a and the second light-emitting layer 13R_a, the first light-emitting layer 13B_a is located on the anode 11R / 11B side and the second light-emitting layer 13R_a is located on the cathode 15 side, and of the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b, the third light-emitting layer 13B_b is located on the anode 11R / 11B side and the fourth light-emitting layer 13R_b is located on the cathode 15 side; however, one embodiment of the present invention is not limited to this. The first light-emitting layer 13B_a may be located on the cathode 15 side, the second light-emitting layer 13R_a may be located on the anode 11R, 11B side, and of the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b, the third light-emitting layer 13B_b may be located on the cathode 15 side, and the fourth light-emitting layer 13R_b may be located on the anode 11R, 11B side.

[0047] The light-emitting device 10G includes a first light-emitting layer 13G_a, a second light-emitting layer 13G_b, and an intermediate layer 21 between the anode 11G and the cathode 15. The intermediate layer 21 is preferably located between the first light-emitting layer 13G_a and the second light-emitting layer 13G_b. The light-emitting device 10G also includes a first hole-injection-transport layer 12_a, a first electron-injection-transport layer 14_a, a second hole-injection-transport layer 12_b, and a second electron-injection-transport layer 14_b. The first hole injection / transport layer 12_a is located between the anode 11B and the first light-emitting layer 13G_a, the first electron injection / transport layer 14_a is located between the first light-emitting layer 13G_a and the intermediate layer 21, the second hole injection / transport layer 12_b is located between the intermediate layer 21 and the second light-emitting layer 13G_b, and the second electron injection / transport layer 14_b is located between the second light-emitting layer 13G_b and the cathode 15.

[0048] The first light-emitting layer 13G_a and the second light-emitting layer 13G_b contain light-emitting materials with emission colors different from those of the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b of the light-emitting devices 10R and 10B, respectively. The emission color of the light-emitting device 10G is different from that of the light-emitting devices 10R and 10B. Therefore, in the display device 100, the subpixel 50G can be a subpixel with emission colors different from those of the subpixels 50R and 50B, even if a colored layer is not provided in the subpixel 50G.

[0049] For example, when a blue light-emitting material is used for the first light-emitting layer 13B_a and the third light-emitting layer 13B_b of the light-emitting devices 10R and 10B and a red light-emitting material is used for the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b of the light-emitting devices 10R and 10B, it is preferable to use a green light-emitting material for the first light-emitting layer 13G_a and the second light-emitting layer 13G_b of the light-emitting device 10G. As another example, when a green light-emitting material is used for the first light-emitting layer 13B_a and the third light-emitting layer 13B_b of the light-emitting devices 10R and 10B and a red light-emitting material is used for the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b of the light-emitting devices 10R and 10B, it is preferable to use a blue light-emitting material for the first light-emitting layer 13G_a and the second light-emitting layer 13G_b of the light-emitting device 10G. As yet another example, if a blue luminescent material is used for the first luminescent layer 13B_a and the third luminescent layer 13B_b of the light-emitting devices 10R and 10B and a green luminescent material is used for the second luminescent layer 13R_a and the fourth luminescent layer 13R_b of the light-emitting devices 10R and 10B, it is preferable to use a red luminescent material for the first luminescent layer 13G_a and the second luminescent layer 13G_b of the light-emitting device 10G.

[0050] In this specification and the like, the blue wavelength region refers to a wavelength region of 400 nm or more and less than 490 nm, blue emission refers to emission having a maximum peak in the emission spectrum in this region, and a blue light-emitting substance refers to a light-emitting substance having a maximum peak in the emission spectrum in this region. The green wavelength region refers to a wavelength region of 490 nm or more and less than 580 nm, green emission refers to emission having a maximum peak in the emission spectrum in this region, and a green light-emitting substance refers to a light-emitting substance having a maximum peak in the emission spectrum in this region. The red wavelength region refers to a wavelength region of 580 nm or more and less than 750 nm, red emission refers to emission having a maximum peak in the emission spectrum in this region, and a red light-emitting substance refers to a light-emitting substance having a maximum peak in the emission spectrum in this region.

[0051] Furthermore, it is preferable that the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b of the light-emitting devices 10R and 10B, and the first light-emitting layer 13G_a and the second light-emitting layer 13G_b of the light-emitting device 10G each contain one or more organic compounds (host materials, etc.) in addition to the light-emitting substance (guest material).

[0052] The intermediate layer 21 is a layer containing an organic compound and an alkali metal or alkaline earth metal. As described above, the intermediate layer 21 is preferably a common layer. Therefore, the intermediate layer 21 in the light-emitting device 10R, the intermediate layer 21 in the light-emitting device 10G, and the intermediate layer 21 in the light-emitting device 10B each preferably contain an organic compound and an alkali metal or alkaline earth metal, and more preferably contain the same organic compound and the same alkali metal or alkaline earth metal. In this specification and the like, the intermediate layer may also be referred to as a charge generation layer. A more detailed description of the intermediate layer (charge generation layer) will be given later in embodiment 3.

[0053] In the light-emitting devices 10R, 10B, and 10G, the anodes 11R, 11B, and 11G are reflective electrodes, and the cathode 15 is a semi-transparent and semi-reflective electrode, forming a micro-optical resonator (microcavity) structure. This allows the light emitted from each light-emitting layer to resonate between the two electrodes, thereby enhancing the light emitted from the cathode 15 side.

[0054] 2(A), when the anodes 11R, 11B, and 11G of the light-emitting devices 10R, 10B, and 10G are reflective electrodes formed of a laminate structure of reflective conductive materials 11R_a, 11B_a, and 11G_a and light-transmitting conductive materials (transparent conductive films) 11R_b, 11B_b, and 11G_b, optical adjustment can be performed by controlling the film thickness of the transparent conductive films 11R_b, 11B_b, and 11G_b. Specifically, it is preferable to adjust the optical distance (the product of film thickness and refractive index) between the anodes 11R, 11B, and 11G and the cathode 15 to mλ / 2 (where m is an integer greater than or equal to 1) or approximately mλ / 2 for the wavelength λ of light obtained from each light-emitting layer.

[0055] Furthermore, in order to amplify the desired light (wavelength: λ) obtained from each light-emitting layer, it is preferable to adjust the optical distance from anodes 11R, 11B, and 11G to the region (light-emitting region) from which the desired light of each light-emitting layer is obtained, and the optical distance from cathode 15 to the region (light-emitting region) from which the desired light of each light-emitting layer is obtained, to be (2m'+1)λ / 4 (where m' is an integer of 1 or greater) or close to that distance. Note that the light-emitting region here refers to the recombination region of holes and electrons in each light-emitting layer.

[0056] By carrying out such optical adjustment, it is possible to narrow the spectrum of specific monochromatic light obtained from each light-emitting layer, thereby obtaining light emission with good color purity.

[0057] In the above case, the optical distance between the anodes 11R, 11B, and 11G and the cathode 15 can be strictly defined as the total thickness from the reflective region of the anodes 11R, 11B, and 11G to the reflective region of the cathode 15. However, since it is difficult to precisely determine the reflective region of the anodes 11R, 11B, and 11G and the cathode 15, the above-described effect can be sufficiently achieved by assuming that any position of the anodes 11R, 11B, and 11G and the cathode 15 is the reflective region. Furthermore, the optical distance between the anodes 11R, 11B, and 11G and the light-emitting layer from which desired light is obtained can be strictly defined as the optical distance between the reflective region of the anodes 11R, 11B, and 11G and the light-emitting region of the light-emitting layer from which desired light is obtained. However, since it is difficult to precisely determine the reflective region of the anodes 11R, 11B, and 11G and the luminescent region of the luminescent layer from which desired light is obtained, the above-mentioned effect can be sufficiently achieved by assuming any position of the anodes 11R, 11B, and 11G as the reflective region and any position of the luminescent layer from which desired light is obtained as the luminescent region. Furthermore, in the light-emitting devices 10R and 10B, the luminescent regions of the first and second luminescent layers 13B_a and 13R_a can be assumed to be positions corresponding to half the total thickness of the first and second luminescent layers 13B_a and 13R_a, and the luminescent regions of the third and fourth luminescent layers 13B_b and 13R_b can be assumed to be positions corresponding to half the total thickness of the third and fourth luminescent layers 13B_b and 13R_b. In addition, when the light-emitting device 10R, 10B has a buffer layer between the first light-emitting layer 13B_a and the second light-emitting layer 13R_a and between the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b, the position corresponding to half the total film thickness of the first light-emitting layer 13B_a, the buffer layer, and the second light-emitting layer 13R_a can be assumed to be the light-emitting region of the first light-emitting layer 13B_a and the second light-emitting layer 13R_a, and the position corresponding to half the total film thickness of the third light-emitting layer 13B_b, the buffer layer, and the fourth light-emitting layer 13R_b can be assumed to be the light-emitting region of the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b.

[0058] In the light-emitting device according to one embodiment of the present invention, at least one of the anodes 11R, 11B, and 11G and the cathode 15 is a light-transmitting electrode (transparent electrode, semi-transmitting / semi-reflective electrode, etc.). When the light-transmitting electrode is a transparent electrode, the visible light transmittance of the transparent electrode is 40% or more. In addition, in the case of a semi-transmitting / semi-reflective electrode, the visible light reflectance of the semi-transmitting / semi-reflective electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. Furthermore, these electrodes have a resistivity of 1×10 -2 It is preferable to set it to Ωcm or less.

[0059] In the light-emitting device according to one embodiment of the present invention, when one of the anodes 11R, 11B, and 11G and the cathode 15 is a reflective electrode, the reflectivity of the reflective electrode for visible light is set to 40% or more and 100% or less, preferably 70% or more and 100% or less. -2 It is preferable to set it to Ωcm or less.

[0060] Since the red wavelength range (580 nm to 750 nm) is approximately twice the blue wavelength range (400 nm to less than 490 nm), more specifically, 1.18 to 1.88 times, in light-emitting devices 10R and 10B, a combination in which a blue luminescent material is used for first luminescent layer 13B_a and third luminescent layer 13B_b and a red luminescent material is used for second luminescent layer 13R_a and fourth luminescent layer 13R_b can be used to produce a light-emitting device having a microcavity structure that enhances both blue and red emission, which is most preferable. This increases the luminous efficiency of light-emitting devices 10R and 10B and reduces the power consumption of display device 100.

[0061] In a combination in which a blue light-emitting material is used in the first light-emitting layer 13B_a and the third light-emitting layer 13B_b and a red light-emitting material is used in the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b, it is more preferable to use a fluorescent material as the blue light-emitting material and a phosphorescent material as the red light-emitting material. In this case, it is preferable to use a blue light-emitting material and a host material in the first light-emitting layer 13B_a and the third light-emitting layer 13B_b that have a T1 level higher than the T1 level of the red light-emitting material in the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b, as shown in the energy diagram in FIG. 3, the T1 level of the blue light-emitting substance used in the first light-emitting layer 13B_a and the third light-emitting layer 13B_b is denoted as B_T1, and the S1 level of the blue light-emitting substance is denoted as B_S1. The T1 level of the host material used in the first light-emitting layer 13B_a and the third light-emitting layer 13B_b is denoted as HB_T1 and the S1 level of the host material used in the first light-emitting layer 13B_a and the third light-emitting layer 13B_b is denoted as HB_S1. The T1 level of the red light-emitting substance used in the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b is denoted as R_T1. The T1 and S1 levels of the host material used in the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b are denoted as HR_S1,T1. The host material used in the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b is an exciplex that forms an excited state with multiple organic compounds, and its S1 level and T1 level are close to each other.

[0062] 3, energy transfer in the stacked structure of the first light-emitting layer 13B_a and the second light-emitting layer 13R_a or the stacked structure of the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b will be described. As shown in FIG. 3, in the first light-emitting layer 13B_a and the third light-emitting layer 13B_b, energy transfers from the S1 level (HB_S1) of the host material to the S1 level (B_S1) of the blue light-emitting substance along route A1, allowing the blue light-emitting substance to emit light. In the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b, energy transfers from the S1 level and T1 level (HR_S1, T1) of the host material to the T1 level (R_T1) of the red light-emitting substance along route A2, allowing the red light-emitting substance to emit light. Furthermore, as described above, when the T1 level (B_T1) of the blue luminescent material and the T1 level (HB_T1) of the host material used in the first luminescent layer 13B_a and the third luminescent layer 13B_b are higher than the T1 level (R_T1) of the red luminescent material in the second luminescent layer 13R_a and the fourth luminescent layer 13R_b, the energy of the T1 level of the host material can be transferred to the T1 level (R_T1) of the red luminescent material via route A3 and route A5 or route A4, thereby allowing the red luminescent material to emit light efficiently.

[0063] As described above, when a blue luminescent material, particularly a fluorescent material, is used in the first luminescent layer 13B_a and the third luminescent layer 13B_b, and a red luminescent material, particularly a phosphorescent material, is used in the second luminescent layer 13R_a and the fourth luminescent layer 13R_b, the luminous efficiency of the light-emitting devices 10R and 10B can be significantly increased, which is particularly preferable.

[0064] Next, modified examples of the display device 100 will be described with reference to FIGS. 2(B), 4, 5 and 6. FIG.

[0065] The modified example shown in Fig. 2(B) differs from the display device 100 shown in Fig. 1(B) in that the second light-emitting layer 13R_a is thinner than the first light-emitting layer 13B_a, and the fourth light-emitting layer 13R_b is thinner than the third light-emitting layer 13B_b. The other configurations are the same as those of the display device 100 shown in Fig. 1(B), and therefore will not be described here.

[0066] In light-emitting devices such as light-emitting devices 10R and 10B in which two light-emitting layers (light-emitting layer L and light-emitting layer S) with different emission colors are stacked so that they are in direct contact with each other, the emission intensity of light-emitting layer L, which emits light with a long wavelength, may be stronger than the emission intensity of light-emitting layer S, which emits light with a short wavelength. (In this case, the light-emitting substance x contained in light-emitting layer L has an emission spectrum with a peak wavelength that is longer in the wavelength direction than the light-emitting substance y contained in light-emitting layer S.) The reason for this is that light-emitting substance x has lower excitation energy and is more easily excited than light-emitting substance y, so that when the recombination region of the light-emitting device is located near the interface between light-emitting layer L and light-emitting layer S, the recombination energy is more likely to be transferred to light-emitting substance x.

[0067] Therefore, in the light-emitting devices 10R and 10B, it is preferable to make the film thickness of the light-emitting layer L, through which recombination energy easily moves, thinner than the film thickness of the light-emitting layer S, thereby shifting the recombination region of carriers (holes and electrons) to the light-emitting layer S. In the light-emitting devices 10R and 10B, for example, when a blue light-emitting material is used for the first light-emitting layer 13B_a and the third light-emitting layer 13B_b and a red light-emitting material is used for the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b, it is preferable to make the film thickness of the second light-emitting layer 13R_a thinner than the film thickness of the first light-emitting layer 13B_a and the film thickness of the fourth light-emitting layer 13R_b thinner than the film thickness of the third light-emitting layer 13B_b, as in the modified example of the display device 100 shown in FIG. With this configuration, the recombination region can be shifted to the light-emitting layer S, thereby improving the luminous intensity of the light-emitting layer that emits light at a short wavelength, and enabling good luminescence to be obtained from both the light-emitting layer that emits light at a long wavelength and the light-emitting layer that emits light at a short wavelength.

[0068] Alternatively, in the light-emitting devices 10R and 10B, it is preferable to increase the carrier transport property of the light-emitting layer L so that the recombination region is shifted from the interface between the light-emitting layer L and the light-emitting layer S to the light-emitting layer S. Note that, when increasing the carrier transport property of the light-emitting layer on the anode side among the multiple light-emitting layers included in the light-emitting device, it is preferable to increase the hole transport property of the light-emitting layer. That is, it is preferable that the light-emitting layer contains a hole transport material, and it is more preferable that the hole transport property is higher than that of the light-emitting layer on the cathode side. Also, when increasing the carrier transport property of the light-emitting layer on the cathode side among the multiple light-emitting layers, it is preferable to increase the electron transport property of the light-emitting layer. That is, it is preferable that the light-emitting layer contains an electron transport material, and it is more preferable that the electron transport property is higher than that of the light-emitting layer on the anode side. Configuration examples of hole transport materials and electron transport materials will be described later in embodiment 3. 1(B), when a short-wavelength blue light-emitting material is used in the first light-emitting layer 13B_a and the third light-emitting layer 13B_b located on the anode side and a long-wavelength red light-emitting material is used in the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b located on the cathode side, it is preferable to make the electron-transporting properties of the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b higher than those of the first light-emitting layer 13B_a and the third light-emitting layer 13B_b. For example, it is preferable to use an electron-transporting material for the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b and a hole-transporting material for the first light-emitting layer 13B_a and the third light-emitting layer 13B_b. This allows the recombination region to be shifted to the first light-emitting layer 13B_a and the third light-emitting layer 13B_b, thereby enabling good light emission from both the light-emitting layer that emits long-wavelength light and the light-emitting layer that emits short-wavelength light. On the other hand, in the light-emitting devices 10R and 10B, when the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b using a long-wavelength red light-emitting material are located on the anode side and the first light-emitting layer 13B_a and the third light-emitting layer 13B_b using a short-wavelength blue light-emitting material are located on the cathode side, it is preferable to increase the hole-transporting properties of the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b more than those of the first light-emitting layer 13B_a and the third light-emitting layer 13B_b.For example, it is preferable that the second light-emitting layer 13R_a and the fourth light-emitting layer 13R_b are made of a hole-transporting material, and the first light-emitting layer 13B_a and the third light-emitting layer 13B_b are made of an electron-transporting material, which allows the recombination region to be shifted to the first light-emitting layer 13B_a and the third light-emitting layer 13B_b, thereby enabling good light emission from both the light-emitting layer that emits light at a long wavelength and the light-emitting layer that emits light at a short wavelength.

[0069] The modified example shown in Fig. 4(A) differs from the display device 100 shown in Fig. 1(B) in that the light-emitting devices 10R and 10B have hole-blocking layers 19_a and 19_b. The other configurations are the same as those of the display device 100 shown in Fig. 1(B), and therefore a description thereof will be omitted here.

[0070] The hole blocking layer 19_a shown in FIG. 4A can be formed using the same metal mask as the first light-emitting layer 13B_a and the second light-emitting layer 13R_a during the manufacturing process of the display device 100. The hole blocking layer 19_b can also be formed using the same metal mask as the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b during the manufacturing process of the display device 100. Therefore, the hole blocking layers 19_a and 19_b can be provided in the light-emitting devices 10R and 10B without complicating the manufacturing process. Providing the hole blocking layers 19_a and 19_b may control the carrier balance of the light-emitting devices 10R and 10B. Alternatively, providing the hole blocking layers 19_a and 19_b may facilitate optical adjustment of the light-emitting devices 10R and 10B. In this case, the hole blocking layers 19_a and 19_b can also function as optical adjustment layers.

[0071] The modified example shown in Fig. 4(B) differs from the display device 100 shown in Fig. 1(B) in that the light-emitting devices 10R and 10B have electron blocking layers 20_a and 20_b. The other configurations are the same as those of the display device 100 shown in Fig. 1(B), and therefore a description thereof will be omitted here.

[0072] The electron blocking layer 20_a shown in FIG. 4(B) can be formed using the same metal mask as the first light-emitting layer 13B_a and the second light-emitting layer 13R_a during the manufacturing process of the display device 100. The electron blocking layer 20_b can also be formed using the same metal mask as the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b during the manufacturing process of the display device 100. Therefore, the electron blocking layers 20_a and 20_b can be provided in the light-emitting devices 10R and 10B without complicating the manufacturing process. Providing the electron blocking layers 20_a and 20_b may control the carrier balance of the light-emitting devices 10R and 10B. Alternatively, providing the electron blocking layers 20_a and 20_b may facilitate optical adjustment of the light-emitting devices 10R and 10B. In this case, the electron blocking layers 20_a and 20_b can also function as optical adjustment layers.

[0073] The modified example shown in Fig. 5(A) differs from the display device 100 shown in Fig. 1(B) in that the light-emitting devices 10R and 10B have buffer layers 22_a and 22_b. The other configurations are the same as those of the display device 100 shown in Fig. 1(B), and therefore a description thereof will be omitted here.

[0074] 5A, the light-emitting devices 10R and 10B have a buffer layer 22_a between the first light-emitting layer 13B_a and the second light-emitting layer 13R_a, and a buffer layer 22_b between the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b. By providing a buffer layer between the light-emitting layers in this manner, the carrier balance can be adjusted, and the light-emitting devices 10R and 10B can emit light of different wavelengths in a balanced manner.

[0075] The buffer layers 22_a and 22_b may be made of, for example, an electron transport material or a hole transport material. If the buffer layers 22_a and 22_b are too thick, the luminous efficiency of the light-emitting devices 10R and 10B may decrease. When the buffer layers 22_a and 22_b are provided, it is preferable to set the thickness of the buffer layers 22_a and 22_b to 5 nm or less, because this prevents a decrease in the luminous efficiency of the light-emitting devices 10R and 10B and enables light of different wavelengths to be emitted in a balanced manner.

[0076] The modified example shown in Fig. 5(B) differs from the display device 100 shown in Fig. 1(B) in that the light-emitting devices 10R and 10B do not have the second light-emitting layer 13R_a. The other configurations are the same as those of the display device 100 shown in Fig. 1(B), and therefore, a description thereof will be omitted here.

[0077] For example, in the light-emitting devices 10R and 10B, if the fourth light-emitting layer 13R_b between the intermediate layer 21 and the cathode 15 is less susceptible to deterioration than the third light-emitting layer 13B_b, the light-emitting devices 10R and 10B may be sufficiently reliable even if only the first light-emitting layer 13B_a, which emits light of the same color as the third light-emitting layer 13B_b, is provided between the intermediate layer 21 and the anode 11R, 11B as shown in FIG. 5B. Alternatively, in the light-emitting devices 10R and 10B, if the second light-emitting layer 13R_a between the intermediate layer 21 and the anode 11R, 11B is less susceptible to deterioration than the first light-emitting layer 13B_a, the light-emitting devices 10R and 10B may be sufficiently reliable even if only the third light-emitting layer 13B_b, which emits light of the same color as the first light-emitting layer 13B_a, is provided between the intermediate layer 21 and the cathode 15.

[0078] The modified example shown in Fig. 6(A) differs from the display device 100 shown in Fig. 1(B) in that the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b of the light-emitting device 10R are separated from the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b of the light-emitting device 10B. The rest of the configuration is the same as that of the display device 100 shown in Fig. 1(B), so a description thereof will be omitted here.

[0079] In this way, even if the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b of the light-emitting device 10R are separate from the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b of the light-emitting device 10B, these layers can be formed in the same step during the manufacturing process. Therefore, the manufacturing process of the display device 100 can be simplified, and the cost of the display device 100 can be reduced, just as in the case where the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b are layers that are common to the light-emitting devices 10R and 10B.

[0080] Furthermore, since the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b of the light-emitting device 10R can be separated from the first light-emitting layer 13B_a, the second light-emitting layer 13R_a, the third light-emitting layer 13B_b, and the fourth light-emitting layer 13R_b of the light-emitting device 10B, the sub-pixel 50R and the sub-pixel 50B do not need to be adjacent to each other in the pixel 110. This increases the degree of freedom in the configuration of the pixel 110, which is preferable.

[0081] The modified example shown in Fig. 6(B) differs from the display device 100 shown in Fig. 1(B) in that a colored layer 136G overlapping the light-emitting device 10G is provided on the substrate 124. The other configurations are the same as those of the display device 100 shown in Fig. 1(B), and therefore will not be described here.

[0082] As shown in FIG. 6B, the subpixel 50G has the light-emitting device 10G and the colored layer 136G overlapping the light-emitting device 10G, so that the chromaticity of the subpixel 50G can be adjusted and the display quality of the display device 100 can be improved.

[0083] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0084] (Embodiment 2) In this embodiment, a manufacturing method of the display device 100, which is a display device of one embodiment of the present invention, will be described with reference to FIGS. 7 to 9, which are cross-sectional views of the display device 100 taken along dashed dotted line X1-X2 in FIG.

[0085] Thin films (insulating films, semiconductor films, conductive films, etc.) that make up display devices can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), and atomic layer deposition (ALD). CVD methods include plasma enhanced chemical vapor deposition (PECVD) and thermal CVD. One type of thermal CVD method is metal organic chemical vapor deposition (MOCVD).

[0086] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, and knife coating.

[0087] In particular, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet printing can be used to fabricate light-emitting devices. Vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, as well as chemical vapor deposition (CVD). In particular, functional layers included in the EL layer (e.g., hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer) can be formed by vapor deposition (e.g., vacuum deposition), coating methods (e.g., dip coating, die coating, bar coating, spin coating, spray coating), printing methods (e.g., inkjet printing, screen printing, offset printing, flexography, gravure printing, microcontact printing, etc.).

[0088] Furthermore, when processing the thin film that constitutes the display device, it can be processed using a photolithography method or the like. Alternatively, the thin film may be processed using a nanoimprint method, a sandblasting method, a lift-off method or the like. Furthermore, the island-shaped thin film may be directly formed by a film formation method using a shielding mask such as a metal mask.

[0089] There are two typical photolithography methods: one is to form a resist mask on the thin film to be processed, process the thin film by etching or the like, and then remove the resist mask; the other is to form a photosensitive thin film, and then process the thin film into the desired shape by exposure and development.

[0090] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. Other light sources that can be used include ultraviolet light, KrF laser light, and ArF laser light. Exposure can also be performed using immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays can also be used as the light used for exposure. Instead of light used for exposure, an electron beam can also be used. Extreme ultraviolet light, X-rays, or an electron beam are preferred because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0091] For etching the thin film, dry etching, wet etching, sandblasting, or the like can be used.

[0092] First, anodes 11R, 11G, and 11B are formed on a layer 121 including a transistor (not shown) (see FIG. 7A). First, a conductive film such as a metal film is formed on the layer 121, and then a resist mask is formed by photolithography, and unnecessary portions of the conductive film are removed by etching. Then, the resist mask is removed, thereby forming the anodes 11R, 11G, and 11B.

[0093] Next, an insulating layer 125 is formed on the layer 121 at a position that does not overlap with the anodes 11R, 11G, and 11B (see FIG. 7(B)). Although not shown, part of the insulating layer 125 may overlap with the ends of the anodes 11R, 11G, and 11B.

[0094] Next, the first hole injection / transport layer 12_a is formed on the anodes 11R, 11G, and 11B and the insulating layer 125 (see FIG. 7(C)).

[0095] Next, the first light-emitting layer 13B_a and the second light-emitting layer 13R_a are formed on the first hole injection / transport layer 12_a at positions overlapping with the anodes 11R and 11B by vacuum deposition using a metal mask (see FIG. 7(D)). At this time, the first light-emitting layer 13B_a and the second light-emitting layer 13R_a can be formed consecutively using the same metal mask.

[0096] Furthermore, a first light-emitting layer 13G_a is formed on the first hole injection / transport layer 12_a at a position overlapping with the anode 11G by vacuum deposition using a metal mask (see FIG. 8(A)).

[0097] Next, the first electron injection / transport layer 14_a, the intermediate layer 21, and the second hole injection / transport layer 12_b are formed on the first hole injection / transport layer 12_a and the second light-emitting layers 13R_a and 13G_a by vacuum deposition (see Figure 8(B)).

[0098] Next, the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b are formed on the second hole injection / transport layer 12_b at positions overlapping with the anodes 11R and 11B by vacuum deposition using a metal mask (see FIG. 8(C)). At this time, the third light-emitting layer 13B_b and the fourth light-emitting layer 13R_b can be formed successively using the same metal mask.

[0099] Furthermore, a second light-emitting layer 13G_b is formed on the second hole injection / transport layer 12_b at a position overlapping with the anode 11G by vacuum deposition using a metal mask (see FIG. 8(D)).

[0100] Next, a second electron injection / transport layer 14_b is formed on the fourth light-emitting layer 13R_b and the second light-emitting layer 13G_b, and then a cathode 15 is formed on the second electron injection / transport layer 14_b (FIG. 9(A)), thereby providing the light-emitting devices 10R, 10B, and 10G. The cathode 15 can be formed by, for example, sputtering or vacuum deposition.

[0101] Then, a protective layer 122 is formed on the cathode 15 so as to cover the light-emitting devices 10R, 10B, and 10G (FIG. 9(B)).

[0102] Finally, the substrate 124 provided with the colored layers 136R and 136B and the black matrix 137 is attached with the resin layer 123, whereby the display device of one embodiment of the present invention can be manufactured (FIG. 9C).

[0103] In the display device of one embodiment of the present invention, by manufacturing each tandem light-emitting device by the above-described manufacturing method, manufacturing is easier than manufacturing a tandem light-emitting device with a three-color coating method, and therefore manufacturing costs can be reduced.

[0104] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0105] (Embodiment 3) In this embodiment, a structure of a light-emitting device that can be used for a display device of one embodiment of the present invention will be described with reference to FIGS.

[0106] <Basic structure of light-emitting devices> The basic structure of a light-emitting device will be described. FIG. 10A shows a light-emitting device having an EL layer (also referred to as an organic compound layer) including a light-emitting layer between a pair of electrodes. Specifically, the light-emitting device has a structure in which an EL layer 103 is sandwiched between a first electrode 101 and a second electrode 102. In this case, the first electrode 101 functions as an anode, and the second electrode 102 functions as a cathode. The EL layer 103 has a structure in which a hole-injection layer 111, a hole-transport layer 112, a light-emitting layer 113, an electron-transport layer 114, and an electron-injection layer 115 are sequentially stacked on the first electrode 101. Note that the stacked structure of the hole-injection layer 111 and the hole-transport layer 112 may be collectively referred to as a hole-injection / transport layer, as described in Embodiment 1. Furthermore, the stacked structure of the electron-transport layer 114 and the electron-injection layer 115 may be collectively referred to as an electron-injection / transport layer, as described in Embodiment 1. Furthermore, the light-emitting layer 113 may have a structure in which a plurality of light-emitting layers emitting different light colors are stacked in contact with each other, as described in Embodiment 1. When the first electrode 101 is a cathode and the second electrode 102 is an anode, the stacking order of the EL layer 103 is reversed. Specifically, on the first electrode 101 which is a cathode, 111 is an electron injection layer, 112 is an electron transport layer, 113 is a light-emitting layer, 114 is a hole transport layer, and 115 is a hole injection layer.

[0107] FIG. 10B shows a modified example of the stacked structure shown in FIG. 10A. In this case, too, the first electrode 101 functions as an anode, and the second electrode 102 functions as a cathode. This modified example shows a case where a hole-blocking layer and an electron-blocking layer are provided. That is, the EL layer 103 has a structure in which a hole-injection layer 111, a hole-transporting layer 112, an electron-blocking layer 116, a light-emitting layer 113, a hole-blocking layer 117, an electron-transporting layer 114, and an electron-injecting layer 115 are sequentially stacked on the first electrode 101. The light-emitting layer 113 is located between the first electrode 101 and the second electrode 102. Alternatively, as described in Embodiment 1, the light-emitting layer 113 may have a structure in which a plurality of light-emitting layers emitting different colors are stacked in contact with each other. The hole-transporting layer 112 is located between the first electrode 101 and the light-emitting layer 113. The electron transport layer 114 is located between the light-emitting layer 113 and the second electrode 102. The hole injection layer 111 is located between the first electrode 101 and the hole transport layer 112. The electron injection layer 115 is located between the electron transport layer 114 and the second electrode 102. The electron blocking layer 116 is located between the hole transport layer 112 and the light-emitting layer 113. In other words, the hole blocking layer 117 is located between the light-emitting layer 113 and the electron transport layer 114.

[0108] The electron blocking layer 116 is provided, for example, for the purpose of preventing electrons from passing through from the light-emitting layer 113 to the first electrode 101. The hole blocking layer 117 is provided, for example, for the purpose of preventing holes from passing through from the light-emitting layer 113 to the second electrode 102.

[0109] Figure 10(C) shows a light-emitting device with a stacked structure (tandem structure) having multiple (two in Figure 10(C)) EL layers (103a, 103b) between a pair of electrodes, with a charge generation layer 106 between the EL layers. A light-emitting device with a tandem structure can achieve a highly efficient light-emitting device without changing the amount of current.

[0110] The charge generation layer 106 has a function of injecting electrons into one EL layer (103a or 103b) and injecting holes into the other EL layer (103b or 103a) when a potential difference is generated between the first electrode 101 and the second electrode 102. Therefore, in Figure 10(B), when a voltage is applied to the first electrode 101 so that the potential is higher than that of the second electrode 102, electrons are injected from the charge generation layer 106 into the EL layer 103a and holes are injected into the EL layer 103b.

[0111] Note that, in terms of light extraction efficiency, the charge generation layer 106 preferably has transparency to visible light (specifically, the visible light transmittance of the charge generation layer 106 is 40% or more). Furthermore, the charge generation layer 106 functions even if it has lower conductivity than the first electrode 101 and the second electrode 102.

[0112] 10(C), the two EL layers (103a, 103b) each have a light-emitting layer (113a, 113b), and the light-emitting colors of the light-emitting layers can be freely combined. For example, the light-emitting device 10G described in the first embodiment can be a light-emitting device having the structure shown in FIG.

[0113] The light-emitting device shown in Fig. 10(D) is a modified example of the light-emitting device shown in Fig. 10(C). The EL layer 103a has a light-emitting layer 113a_1 and a light-emitting layer 113a_2 that are stacked so as to be in direct contact with each other, and the EL layer 103b has a light-emitting layer 113b_1 and a light-emitting layer 113b_2 that are stacked so as to be in direct contact with each other. For example, the light-emitting device having the structure shown in Fig. 10(D) can be used as the light-emitting devices 10R and 10B described in Embodiment 1.

[0114] The light-emitting device shown in FIG. 10(E) is an example of a light-emitting device with a tandem structure. As shown in the figure, the light-emitting device has a structure in which three EL layers (103a, 103b, and 103c) are stacked with charge generation layers (106a and 106b) sandwiched between them. The three EL layers (103a, 103b, and 103c) each have a light-emitting layer (113a, 113b, and 113c), and the light-emitting colors of the light-emitting layers can be freely combined. For example, the light-emitting layer 113a can be blue, the light-emitting layer 113b can be red, green, or yellow, and the light-emitting layer 113c can be blue. Alternatively, the light-emitting layer 113a can be red, the light-emitting layer 113b can be blue, green, or yellow, and the light-emitting layer 113c can be red. The light-emitting layers (113a, 113b, and 113c) may have a stacked structure in which multiple light-emitting layers of different light-emitting colors are in contact with each other, as described in Embodiment 1.

[0115] <Specific structure of the light-emitting device> Next, a specific structure of a light-emitting device according to one embodiment of the present invention will be described. Here, the description will be made with reference to FIG. 10C, which has a tandem structure. Note that the structure of the EL layer of a light-emitting device having a single structure shown in FIGS. 10A and 10B is similar.

[0116] <First electrode and second electrode> The materials forming the first electrode 101 and the second electrode 102 can be any combination of the following materials, as long as they fulfill the functions of both electrodes described above. For example, metals, alloys, electrically conductive compounds, and mixtures thereof can be used. Specific examples include In-Sn oxide (also referred to as ITO), In-Si-Sn oxide (also referred to as ITSO), In-Zn oxide, and In-W-Zn oxide. Other metals that can be used include 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 any combination of these metals. Other examples that can be used include elements belonging to Group 1 or 2 of the periodic table (e.g., lithium (Li), cesium (Cs), calcium (Ca), and strontium (Sr)), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing appropriate combinations of these elements, as well as graphene.

[0117] 10(C), when the first electrode 101 is an anode, the hole injection layer 111a and the hole transport layer 112a of the EL layer 103a are sequentially laminated by vacuum deposition on the first electrode 101. After the EL layer 103a and the charge generation layer 106 are formed, the hole injection layer 111b and the hole transport layer 112b of the EL layer 103b are similarly sequentially laminated on the charge generation layer 106.

[0118] <Hole injection layer> The hole injection layers (111, 111a, 111b) are layers that inject holes from the first electrode 101, which is an anode, and the charge generation layers (106, 106a, 106b) to the EL layers (103, 103a, 103b), and contain an organic acceptor material and a material with high hole injection properties.

[0119] An organic acceptor material is a material that can generate holes in an organic compound by causing charge separation between the organic acceptor material and another organic compound whose LUMO level and HOMO level are close to each other. Therefore, compounds having an electron-withdrawing group (a halogen group or a cyano group), such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives, can be used as the organic acceptor material. For example, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, 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-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile, and the like can be used. Among organic acceptor materials, compounds such as HAT-CN, in which an electron-withdrawing group is bonded to a fused aromatic ring containing multiple heteroatoms, are particularly suitable because of their high acceptability and thermal stability. Radialene derivatives with electron-withdrawing groups (especially halogen groups such as fluoro groups or cyano groups) are also preferred because of their extremely high electron-accepting properties. Specific examples 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].

[0120] As a material with high hole injection properties, an oxide of a metal belonging to Groups 4 to 8 of the periodic table (e.g., transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide) can be used. Specific examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is preferred because it is stable in air, has low hygroscopicity, and is easy to handle. In addition, diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA-F6), perylene tetracarboxylic acid derivatives such as 3,4,9,10-perylene tetracarboxylic diimide (abbreviation: PTCDI), and 3,4,9,10-perylene tetracarboxylic-bis-benzimidazole (abbreviation: PTCBI), (C 60 -Ih)[5,6]fullerene (abbreviation: C 60 ), (C70-D5h)[5,6]fullerene (abbreviation: C 70 Organic compounds such as copper phthalocyanine (abbreviated as CuPc), zinc phthalocyanine (abbreviated as ZnPc), cobalt phthalocyanine (abbreviated as CoPc), iron phthalocyanine (abbreviated as FePc), tin phthalocyanine (abbreviated as SnPc), tin oxide phthalocyanine (abbreviated as SnOPc), titanium oxide phthalocyanine (abbreviated as TiOPc), and vanadium oxide phthalocyanine (abbreviated as VOPc) can be used. Phthalocyanine-based metal complexes such as CuPc or ZnPc, or 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine are particularly preferred. Among these, CuPc and ZnPc are preferred due to their low cost and excellent properties. Furthermore, ZnPc has a small diffusion coefficient for silicon, which reduces the risk of metal diffusion into the semiconductor affecting its characteristics, making it particularly suitable for use in display devices that use silicon semiconductors.

[0121] In addition to the above materials, we also have low molecular weight compounds such as 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis[4-bis(3-methylphenyl)aminophenyl]-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: DNTPD), and 1,3,5-tris[N Aromatic amine compounds such as -(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) can be used.

[0122] In addition, polymeric compounds (oligomers, dendrimers, polymers, etc.) such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD) can be used. Alternatively, polymeric compounds with added acids, such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviation: PEDOT / PSS) and polyaniline / polystyrene sulfonic acid (abbreviation: PAni / PSS), can also be used.

[0123] Furthermore, a mixed material containing a hole transport material and the above-mentioned organic acceptor material (electron-accepting material) can also be used as a material with high hole injection properties. In this case, electrons are extracted from the hole transport material by the organic acceptor material, generating holes in the hole injection layer, which are then injected into the light-emitting layer via the hole transport layer. The hole injection layer may be formed as a single layer made of a mixed material containing a hole transport material and an organic acceptor material (electron-accepting material), or may be formed by laminating the hole transport material and the organic acceptor material (electron-accepting material) as separate layers.

[0124] As for hole transporting materials, the hole mobility at a square root of the electric field strength [V / cm] of 600 is 1×10 -6 cm 2 It is preferable that the Vs of the material be 1 / Vs or more. Note that other materials can be used as long as they have a higher hole transporting property than an electron transporting property.

[0125] In addition, the hole transporting material is preferably a compound having a π-electron-rich heteroaromatic ring (for example, a carbazole derivative, a furan derivative, or a thiophene derivative), or an aromatic amine (an organic compound having an aromatic amine skeleton).

[0126] Examples of the carbazole derivatives (organic compounds having a carbazole ring) include bicarbazole derivatives (for example, 3,3'-bicarbazole derivatives), aromatic amines having a carbazolyl group, and the like.

[0127] Specific examples of the bicarbazole derivatives (e.g., 3,3′-bicarbazole derivatives) include 9,9′-diphenyl-9H,9′H-3,3′-bicarbazole (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), and 9-(2-naphthyl)-9′-phenyl-3,3′-bi-9H-carbazole (abbreviation: βNCCP).

[0128] Specific examples of the aromatic amine having a carbazolyl group include 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBiF), and N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBiF). PCBBiF), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]bis(9,9-dimethyl-9H-fluoren-2-yl)amine (abbreviation: PCBFF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-(9,9-dimethyl-9H-fluoren-2-yl)-9,9-dimethyl-9H-fluorene -4-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-diphenyl-9H-fluoren-2-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-diphenyl-9H-fluoren-4-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi(9H-fluorene) )-2-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi(9H-fluoren)-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':3',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-2-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':4',1''-terphenyl-4-yl)-9,9-Dimethyl-9H-fluoren-2-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':3',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':4',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-4-amine, 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), 3-[N-(9-phenyl) 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), N-(9,9-spirobi[9H-fluoren]-2-yl)-N,9-diphenylcarbazol-3-amine (abbreviation: PCASF), N-(4-biphenyl)-4-(carbazol-9-yl)phenylaniline (abbreviated as YGA1BP), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviated as YGA2F), 4,4',4''-tris(carbazol-9-yl)triphenylamine (abbreviated as TCTA), etc.

[0129] In addition to the above, examples of the carbazole derivatives include 9-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]phenanthrene (abbreviation: PCPPn), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), and 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA).

[0130] Specific examples of the furan derivatives (organic compounds having a furan ring) include 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).

[0131] Specific examples of the thiophene derivatives (organic compounds having a thiophene ring) include organic compounds having a thiophene ring, such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV).

[0132] Specific examples of the aromatic amine include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), 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 ... -phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), N-(9,9-spirobi[9H-fluoren]-2-yl )-N,N'N'-triphenyl-1,4-phenylenediamine (abbreviation: DPASF), N,N'-diphenyl-N,N'-bis(4-diphenylaminophenyl)spirobi[9H-fluorene]-2,7-diamine (abbreviation: DPA2SF), 4,4',4''-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamine amino]triphenylamine (abbreviation: m-MTDATA), N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), DNTPD, 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-Bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2- d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4', 4''-Diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4''-( 7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl] 4'-[4'-(3-phenyl-9H-carbazol-9-yl)biphenyl-4-yl]-4''-phenyltriphenylamine (abbreviated as TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviated as αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviated as αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviated as YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)furan N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N- Bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), N,N-bis(9,9-dimethyl-9H-fluorene-2- N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, and the like are mentioned.

[0133] Other examples of hole-transporting materials that can be used include polymeric compounds (oligomers, dendrimers, polymers, etc.) such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD). Alternatively, polymeric compounds with added acids, such as poly(3,4-ethylenedioxythiophene) / polystyrenesulfonic acid (abbreviation: PEDOT / PSS) and polyaniline / polystyrenesulfonic acid (abbreviation: PAni / PSS), can also be used.

[0134] However, the hole transporting material is not limited to the above, and one or more of various known materials may be used as the hole transporting material.

[0135] The hole injection layers (111, 111a, 111b) can be formed using various known film formation methods, for example, vacuum deposition.

[0136] <Hole transport layer> The hole transport layers (112, 112a, 112b) are layers that transport holes injected from the first electrode 101 by the hole injection layers (111, 111a, 111b) to the light-emitting layers (113, 113a, 113b, 113c). The hole transport layers (112, 112a, 112b) are layers that contain a hole transport material. Therefore, the hole transport layers (112, 112a, 112b) can use the same hole transport material that can be used for the hole injection layers (111, 111a, 111b).

[0137] In the light-emitting device of one embodiment of the present invention, the light-emitting layers (113, 113a, 113b, and 113c) can be formed using the same organic compound as that used in the hole-transport layers (112, 112a, and 112b). It is more preferable to use the same organic compound in the hole-transport layers (112, 112a, and 112b) and the light-emitting layers (113, 113a, 113b, and 113c) because holes can be efficiently transported from the hole-transport layers (112, 112a, and 112b) to the light-emitting layers (113, 113a, 113b, and 113c).

[0138] <Electron Blocking Layer> The electron blocking layer 116 is provided for the purpose of preventing electrons from passing through from the light-emitting layer 113 to the first electrode 101. A material having excellent hole-transporting properties, poor electron-transporting properties, and a high LUMO level is suitable for the electron blocking layer 116. Among the substances listed above that can be used as the material for the hole-transporting layer 112, it is preferable to form the layer using a material having a LUMO level higher than the LUMO level of the material (at least the host material) constituting the light-emitting layer, preferably 0.30 eV or more higher. Note that the electron blocking layer can also be regarded as part of the hole-transporting layer 112 because it transports holes.

[0139] <Light-emitting layer> The light-emitting layers (113, 113a, 113b, 113c) are layers containing a light-emitting substance. As the light-emitting substance that can be used for the light-emitting layers (113, 113a, 113b, 113c), substances that emit light of colors such as blue, purple, blue-purple, green, yellow-green, yellow, orange, and red can be appropriately used. When multiple light-emitting layers are provided, different light-emitting substances can be used for each light-emitting layer to produce different light-emitting colors (for example, white light emission obtained by combining complementary light-emitting colors). When multiple light-emitting layers are provided, each light-emitting layer can also produce the same color. A stacked structure of multiple light-emitting layers with the same light-emitting color can sometimes provide higher reliability than a single-layer structure. Furthermore, a stacked structure in which one light-emitting layer contains different light-emitting substances may be used.

[0140] Furthermore, the light-emitting layers (113, 113a, 113b, 113c) may contain one or more organic compounds (host materials, etc.) in addition to the light-emitting substance (guest material).

[0141] When a plurality of host materials are used in the light-emitting layer (113, 113a, 113b, 113c), it is preferable to use a substance having a larger energy gap as the second host material than the energy gaps of the guest material and the first host material contained in the light-emitting layer. Furthermore, it is preferable that the lowest singlet excitation energy level (S1 level) of the second host material is higher than the S1 level of the first host material, and the lowest triplet excitation energy level (T1 level) of the second host material is higher than the T1 level of the guest material. Furthermore, it is preferable that the lowest triplet excitation energy level (T1 level) of the second host material is higher than the T1 level of the first host material. With this structure, an exciplex can be formed using two types of host materials. To efficiently form an exciplex, it is particularly preferable to combine a compound that easily accepts holes (hole-transporting material) with a compound that easily accepts electrons (electron-transporting material). Furthermore, this structure can simultaneously achieve high efficiency, low voltage, and long life.

[0142] As long as the organic compound used as the host material (including the first host material and the second host material) satisfies the conditions for a host material used in an emitting layer, examples thereof include organic compounds such as hole-transporting materials that can be used in the hole-transporting layers (112, 112a, and 112b) described above and electron-transporting materials that can be used in the electron-transporting layers (114, 114a, and 114b) described below. The organic compound may also be an exciplex composed of multiple organic compounds (the first host material and the second host material described above). An exciplex (also referred to as an exciplex) that forms an excited state with multiple organic compounds has an extremely small difference between the S1 and T1 levels and functions as a thermally activated delayed fluorescence (TADF) material that can convert triplet excitation energy into singlet excitation energy. In addition, as a combination of multiple organic compounds that form an exciplex, for example, one of them may have a π-electron-deficient heteroaromatic ring and the other may have a π-electron-rich heteroaromatic ring. Note that as a combination that forms an exciplex, one of the organic compounds may be a phosphorescent material such as an iridium-, rhodium-, or platinum-based organometallic complex or a metal complex.

[0143] There are no particular limitations on the light-emitting substance that can be used in the light-emitting layer (113, 113a, 113b, 113c), and light-emitting substances that convert singlet excitation energy into light emission in the visible light range, or light-emitting substances that convert triplet excitation energy into light emission in the visible light range, can be used.

[0144] <Light-emitting material that converts singlet excitation energy into light> Examples of luminescent materials that convert singlet excitation energy into luminescence and can be used in the luminescent layers (113, 113a, 113b, 113c) include the following fluorescent substances (fluorescent luminescent materials): pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives. Pyrene derivatives are particularly preferred because of their high luminescence quantum yield. Specific examples of pyrene derivatives include 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'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N,N'-bis(dibenzothiophen-2-yl)-N, N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviation: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), and the like.

[0145] In addition, 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'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenyl-4,4'-stilbenediamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)phenyl N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4'-(9,10-diphenyl-2-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), 4-(10-phenyl-9-anthryl)-4'- (9-Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), 4-[4-(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenyl) N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), and the like can be used.

[0146] In addition, N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-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,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 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-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinit (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhA FD), 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),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), 1,6BnfAPrn-0 3, N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazol-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviated as 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10FrA2Nbf(IV)-02), etc. In particular, pyrenediamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 can be used.

[0147] <Light-emitting material that converts triplet excitation energy into light> Next, examples of the light-emitting material that can be used in the light-emitting layer 113 and converts triplet excitation energy into light emission include a phosphorescent material (phosphorescent material) and a TADF material that exhibits thermally activated delayed fluorescence.

[0148] A phosphorescent material is a compound that exhibits phosphorescence but does not exhibit fluorescence at a temperature range from low temperatures (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, such as an organometallic complex, a metal complex (platinum complex), or a rare-earth metal complex. Specifically, transition metal elements are preferred as metal elements with a large spin-orbit interaction, and platinum group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt)) are particularly preferred. Among these, iridium is preferred because it can increase the transition probability associated with the direct transition between the singlet ground state and the triplet excited state.

[0149] <Phosphorescent materials (400 nm or more but less than 580 nm: blue or green)> Examples of phosphorescent materials that exhibit blue or green light and have an emission spectrum with a peak wavelength of 400 nm or more and less than 580 nm include the following materials.

[0150] For example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]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] Organometallic complexes containing a 4H-triazole ring, such as 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]), tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1- Organometallic complexes containing a 1H-triazole ring, such as 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(II) Iridium(III) tetrakis(1-pyrazolyl)borate (abbreviated as FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C2']iridium(III) picolinate (abbreviated as FIrpic), and bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C2']iridium(III) tetrakis(1-pyrazolyl)borate (abbreviated as FIr6). 2’}iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’] Organometallic complexes with a phenylpyridine derivative having an electron-withdrawing group as a ligand, such as iridium(III) acetylacetonate (abbreviation: FIr(acac)), are also included.

[0151] <Phosphorescent material (490nm or more but less than 590nm: green or yellow)> Examples of phosphorescent materials that exhibit green or yellow color and have an emission spectrum with a peak wavelength of 490 nm or more and less than 590 nm include the following materials.

[0152] 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(mppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-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-κN3]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp)2(acac)]), and (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]). iridium complexes, organometallic iridium complexes containing a pyrazine ring such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), tris(2-phenylpyridinato-N,C 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-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), {2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofuro Ir(2,3-b)pyridin-7-yl-κC}bis{5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridinyl-κN]phenyl-κC}iridium(III) (abbreviated as Ir(5mtpy-d6)2(mbfpypy-iPr-d4)), [2-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC] Organometallic iridium complexes containing a pyridine ring, such as [2-(4-methyl-5-phenyl-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(mdppy)), and bis(2,4-diphenyl-1,3-oxazolato-N,C 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 (abbreviated as [Ir(bt)2(acac)]), as well as rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviated as [Tb(acac)3(Phen)]).

[0153] <Phosphorescent materials (570 nm or more but less than 750 nm: yellow or red)> 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 less than 750 nm include the following materials.

[0154] For example, pyrimidinato]iridium(III) such as (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)]), and (dipivaloylmethanato)bis[4,6-di(naphthalen-1-yl)pyrimidinato]iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]). Organometallic complexes containing an imidine ring, (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)]), and bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κN). 2O,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)]), organometallic complexes with a pyrazine ring such as (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’ ) iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), and bis[4,6-dimethyl-2-(2-quinolinyl-κN)phenyl-κC](2,4-pentanedionato-κ 2Examples of such complexes include organometallic complexes with a pyridine ring, such as (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]), and rare earth metal complexes, such as 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)]).

[0155] ≪TADF material≫ The following materials can be used as TADF materials. TADF materials are materials that have a small difference between the S1 level and the T1 level (preferably 0.20 eV or less), can upconvert a triplet excited state to a singlet excited state with a small amount of thermal energy (reverse intersystem crossing), and efficiently emit light (fluorescence) from the singlet excited state. Conditions for efficiently obtaining thermally activated delayed fluorescence include an energy difference between the triplet excited energy level and the singlet excited energy level of 0.00 eV or more and 0.20 eV or less, preferably 0.00 eV or more and 0.10 eV or less. Delayed fluorescence in TADF materials refers to light emission that has a spectrum similar to that of normal fluorescence but has a significantly long lifetime. Its lifetime is 1×10 -6 seconds or 1×10 -3 More than a second.

[0156] The TADF material can also be used as an electron transporting material, a hole transporting material, or a host material.

[0157] Examples of TADF materials include fullerene and its derivatives, acridine derivatives such as proflavine, eosin, etc. Also included are metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complex (abbreviation: SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (abbreviation: SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (abbreviation: SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (abbreviation: SnF2(OEP)), etioporphyrin-tin fluoride complex (abbreviation: SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (abbreviation: PtCl2OEP).

[0158] [ka]

[0159] Other examples include 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxy) 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9, 9-Dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracen]-10'-one (abbreviation: ACRSA), 4-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)benzofuro[3,2-d]pyrimidine (abbreviation: 4PCCzBfpm), 4-[4-(9'-phenyl-3,3'- Heteroaromatic compounds having a π-electron rich heteroaromatic compound and a π-electron deficient heteroaromatic compound, such as 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), may also be used.

[0160] In addition, a substance in which a π-electron-rich heteroaromatic compound and a π-electron-deficient heteroaromatic compound are directly bonded is particularly preferable because the donor property of the π-electron-rich heteroaromatic compound and the acceptor property of the π-electron-deficient heteroaromatic compound are both strong, thereby reducing the energy difference between the singlet excited state and the triplet excited state. Furthermore, a TADF material (TADF100) in which the singlet excited state and the triplet excited state are in thermal equilibrium may also be used as the TADF material. Such TADF materials have a short emission lifetime (excitation lifetime), which can suppress efficiency decline in light-emitting devices in the high-brightness range.

[0161] [ka]

[0162] In addition to the above, examples of materials capable of converting triplet excitation energy into luminescence include nanostructures of transition metal compounds having a perovskite structure. Nanostructures of metal halide perovskites are particularly preferred. Nanoparticles and nanorods are preferred as such nanostructures.

[0163] In the light-emitting layers (113, 113a, 113b, 113c), one or more substances having an energy gap larger than the energy gap of the light-emitting substance (guest material) may be selected and used as the organic compound (host material, etc.) used in combination with the above-mentioned light-emitting substance (guest material).

[0164] <Fluorescent host material> When the light-emitting substance used in the light-emitting layers (113, 113a, 113b, and 113c) is a fluorescent light-emitting substance, it is preferable to use, as the organic compound (host material) to be combined, an organic compound having a high energy level in a singlet excited state and a low energy level in a triplet excited state, or an organic compound with a high fluorescence quantum yield. Therefore, as long as the organic compound satisfies these conditions, a hole-transporting material (described above) and an electron-transporting material (described below) shown in this embodiment can be used.

[0165] Although some of the examples overlap with those described above, examples of the organic compound (host material) that can be preferably combined with the light-emitting substance (fluorescent light-emitting substance) include condensed polycyclic aromatic compounds such as anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives.

[0166] Specific examples of organic compounds (host materials) that are preferably used in combination with fluorescent materials include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9,10-diphenylanthracene (abbreviation: DPAnth), N,N ... N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviated as CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviated as DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine (abbreviated as PCAPBA), N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviated as 2PCAPA) , 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthracenyl)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), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,β-ADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth), 2,9-di(1-naphthyl)-10-phenylanthracene (abbreviated as 2αN-αNPhA), 9-(1-naphthyl)-10-[3-(1-naphthyl)phenyl]anthracene (abbreviation: αN-mαNPAnth), 9-(2-naphthyl)-10-[3-(1-naphthyl)phenyl]anthracene (abbreviation: βN-mαNPAnth), 9-(1-naphthyl)-10-[4-(1-naphthyl)phenyl]anthracene (abbreviation: αN-αNPAnth), 9-(2-naphthyl)-10-[4-(2-naphthyl)phenyl] Anthracene (abbreviation: βN-βNPAnth), 2-(1-naphthyl)-9-(2-naphthyl)-10-phenylanthracene (abbreviation: 2αN-βNPhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthracenyl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtB ImPBPhA), 9,9'-bianthryl (abbreviated as BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviated as DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviated as DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviated as TPB3), 5,12-diphenyltetracene, 5,12-bis(biphenyl-2-yl)tetracene, etc.

[0167] <Phosphorescent host material> Furthermore, when the light-emitting substance used in the light-emitting layers (113, 113a, 113b, 113c) is a phosphorescent light-emitting substance, an organic compound having a higher triplet excitation energy (energy difference between the ground state and the triplet excited state) than the triplet excitation energy of the light-emitting substance can be selected as the organic compound (host material) to be combined. Note that when multiple organic compounds (for example, a first host material and a second host material (or assist material)) are used in combination with the light-emitting substance to form an exciplex, it is preferable to use these multiple organic compounds in combination with the phosphorescent light-emitting substance.

[0168] With this structure, it is possible to efficiently obtain light emission using Exciplex-Triplet Energy Transfer (ExTET), which is an energy transfer from an exciplex to a light-emitting substance. As a combination of multiple organic compounds, it is preferable to use one that easily forms an exciplex, and it is particularly preferable to combine a compound that easily accepts holes (hole transport material) with a compound that easily accepts electrons (electron transport material).

[0169] Although some of the examples overlap with those described above, examples of the organic compound (host material, assist material) that can be preferably combined with the light-emitting substance (phosphorescent light-emitting substance) include aromatic amines (organic compounds having an aromatic amine skeleton), carbazole derivatives (organic compounds having a carbazole ring), dibenzothiophene derivatives (organic compounds having a dibenzothiophene ring), dibenzofuran derivatives (organic compounds having a dibenzofuran ring), oxadiazole derivatives (organic compounds having an oxadiazole ring), triazole derivatives (organic compounds having a triazole ring), benzimidazole derivatives (benzo Examples of suitable organic compounds include organic compounds having an imidazole ring, quinoxaline derivatives (organic compounds having a quinoxaline ring), dibenzoquinoxaline derivatives (organic compounds having a dibenzoquinoxaline ring), pyrimidine derivatives (organic compounds having a pyrimidine ring), triazine derivatives (organic compounds having a triazine ring), pyridine derivatives (organic compounds having a pyridine ring), bipyridine derivatives (organic compounds having a bipyridine ring), phenanthroline derivatives (organic compounds having a phenanthroline ring), furodiazin derivatives (organic compounds having a furodiazin ring), zinc- and aluminum-based metal complexes, and the like.

[0170] Among the organic compounds, specific examples of the aromatic amine and carbazole derivative, which are organic compounds with high hole-transport properties, include the same as the specific examples of the hole-transport material described above, and any of these is preferable as the host material.

[0171] Specific examples of the dibenzothiophene derivatives and dibenzofuran derivatives, which are organic compounds with high hole transport properties among the above organic compounds, include 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), DBT3P-II, 2,8-dipheny Examples of suitable host materials include 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and 4-[3-(triphenylen-2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II).

[0172] Other preferred host materials include metal complexes having oxazole- or thiazole-based ligands, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ).

[0173] Specific examples of the organic compounds having high electron transport properties, such as oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, quinazoline derivatives, and phenanthroline derivatives, among the above organic compounds, include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9 -[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), Organic compounds containing heteroaromatic rings with polyazole rings, such as 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and compounds containing heteroaromatic rings with phenanthroline rings, such as bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), and 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P). The organic compounds, 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-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,and organic compounds containing a heteroaromatic ring having a dibenzoquinoxaline ring, such as 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN), and 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), all of which are preferable as host materials. ,

[0174] Specific examples of the pyridine derivatives, diazine derivatives (including pyrimidine derivatives, pyrazine derivatives, and pyridazine derivatives), triazine derivatives, and furodiazine derivatives, which are organic compounds with high electron transport properties among the above organic compounds, include 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), and 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II). Pyrimidine (abbreviation: 4,6mCzP2Pm), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1 ,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2- d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 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), 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr), 11-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine, 11-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine, 12-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 12PCCzPnfpr), 9-[3'-(9 -phenyl-9H-carbazol-3-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9pmPCBPNfpr), 9-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9PCCzNfpr), 10-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 10PCCzNfpr), 9-[3'-(6-phenylbenzo[b]naphtho [1,2-d]furan-8-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mBnfBPNfpr), 9-{3-[6-(9,9-dimethylfluoren-2-yl)dibenzothiophen-4-yl]phenyl}naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mFDBtPNfpr), 9-[3'-(6-phenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr-02), 9-[3-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)phenyl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mPCCzPNfpr), 9-[3'-(2,8-diphenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine, 11-[3'-(2,8-diphenyldibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine, 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'-(triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 2-(biphenyl-4-yl)-4-phenyl-6-(9, 9'-Spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-furan Examples of suitable host materials include organic compounds containing heteroaromatic rings with diazine rings, such as 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), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), and 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm).

[0175] Furthermore, among the above organic compounds, specific examples of metal complexes, which are organic compounds with high electron-transporting properties, include zinc- or aluminum-based metal complexes such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), and bis(8-quinolinolato)zinc(II) (abbreviation: Znq), as well as metal complexes having a quinoline ring or a benzoquinoline ring, all of which are preferable as the host material.

[0176] Other preferred host materials include polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy).

[0177] Furthermore, we have developed bipolar organic compounds with high hole-transporting and electron-transporting properties, such as 9-phenyl-9'-(4-phenyl-2-quinazolinyl)-3,3'-bi-9H-carbazole (abbreviation: PCCzQz), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[ Organic compounds having a diazine ring, such as [2,1-b]carbazole (abbreviation: mINc(II)PTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenyl-indolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), and 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), can also be used as the host material.

[0178] <Hole-blocking layer> The hole-blocking layer 117 is provided for the purpose of preventing holes from penetrating from the light-emitting layer 113 to the second electrode 102. A material having excellent electron-transporting properties, low hole-transporting properties, and a deep HOMO level is suitable for the hole-blocking layer 117. Among the materials that can be used as the material for the electron-transporting layer 114 described later, a material having a HOMO level lower than the HOMO level of the material (at least the host material) constituting the light-emitting layer, preferably lower by 0.30 eV or more, is preferably used for the hole-blocking layer 117. Note that the hole-blocking layer can also be regarded as part of the electron-transporting layer 114 because it transports electrons.

[0179] <Electron transport layer> The electron transport layers (114, 114a, 114b) are layers that transport electrons injected from the second electrode 102 and the charge generation layers (106, 106a, 106b) by the electron injection layers (115, 115a, 115b) described later to the light-emitting layers (113, 113a, 113b, 113c). Note that the heat resistance of the light-emitting device according to one embodiment of the present invention can be improved by the electron transport layer having a stacked structure. In addition, the electron transport material used for the electron transport layers (114, 114a, 114b) has an electron mobility of 1×10 or more at a square root of an electric field strength [V / cm] of 600. -6 cm 2 / Vs or higher is preferable. Note that other substances can be used as long as they have a higher electron transporting property than hole transporting property. The electron transport layers (114, 114a, 114b) function as single layers, but may also have a stacked structure of two or more layers.

[0180] ≪Electron transport material≫ The electron transport material that can be used for the electron transport layer (114, 114a, 114b) can be an organic compound with high electron transport properties, such as a heteroaromatic compound. A heteroaromatic compound is a cyclic compound containing at least two different elements in the ring. The ring structure can be a three-, four-, five-, or six-membered ring, with a five- or six-membered ring being particularly preferred. The element contained in the heteroaromatic compound is preferably one or more of nitrogen, oxygen, or sulfur in addition to carbon. Heteroaromatic compounds containing nitrogen (nitrogen-containing heteroaromatic compounds) are particularly preferred, and it is preferable to use a material with high electron transport properties (electron transport material) such as a nitrogen-containing heteroaromatic compound or a π-electron-deficient heteroaromatic compound containing the same.

[0181] The electron transport material may be a material different from the material used in the light-emitting layer. Not all of the excitons generated by carrier recombination in the light-emitting layer can contribute to light emission, and they may diffuse to layers adjacent to or located nearby the light-emitting layer. To avoid this phenomenon, it is preferable that the energy level (lowest singlet excitation level or lowest triplet excitation level) of the material used in the layer adjacent to or located nearby the light-emitting layer is higher than that of the material used in the light-emitting layer. Therefore, by using a material different from the material used in the light-emitting layer as the electron transport material, a highly efficient device can be obtained.

[0182] A heteroaromatic compound is an organic compound that contains at least one heteroaromatic ring.

[0183] The heteroaromatic ring has any one of a pyridine ring, a diazine ring, a triazine ring, a polyazole ring, an oxazole ring, a thiazole ring, etc. The heteroaromatic ring having a diazine ring includes a heteroaromatic ring having a pyrimidine ring, a pyrazine ring, a pyridazine ring, etc. The heteroaromatic ring having a polyazole ring includes a heteroaromatic ring having an imidazole ring, a triazole ring, or an oxadiazole ring.

[0184] The heteroaromatic ring also includes a fused heteroaromatic ring having a fused ring structure, such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a phenanthroline ring, a phlodiazin ring, or a benzimidazole ring.

[0185] Among heteroaromatic compounds containing one or more of nitrogen, oxygen, and sulfur in addition to carbon, examples of heteroaromatic compounds having a five-membered ring structure include heteroaromatic compounds having an imidazole ring, heteroaromatic compounds having a triazole ring, heteroaromatic compounds having an oxazole ring, heteroaromatic compounds having an oxadiazole ring, heteroaromatic compounds having a thiazole ring, and heteroaromatic compounds having a benzimidazole ring.

[0186] Furthermore, among heteroaromatic compounds containing one or more of nitrogen, oxygen, and sulfur in addition to carbon, examples of heteroaromatic compounds having a six-membered ring structure include heteroaromatic compounds having a heteroaromatic ring such as a pyridine ring, a diazine ring (including a pyrimidine ring, a pyrazine ring, and a pyridazine ring), a triazine ring, and a polyazole ring.Heteroaromatic compounds having a structure in which pyridine rings are linked include heteroaromatic compounds having a bipyridine structure and heteroaromatic compounds having a terpyridine structure.

[0187] Furthermore, examples of heteroaromatic compounds having a fused ring structure partially containing the above-mentioned 6-membered ring structure include heteroaromatic compounds having a fused heteroaromatic ring such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a phenanthroline ring, a furodiazine ring (including a structure in which an aromatic ring is fused to the furan ring of a furodiazine ring), and a benzimidazole ring.

[0188] Specific examples of the heteroaromatic compound having a five-membered ring structure (such as a polyazole ring (including an imidazole ring, a triazole ring, and an oxadiazole ring), an oxazole ring, a thiazole ring, and a benzimidazole ring) include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-furan (abbreviation: FURAN ... phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and the like.

[0189] Specific examples of the heteroaromatic compound having a 6-membered ring structure (including heteroaromatic rings having a pyridine ring, a diazine ring, a triazine ring, or the like) include heteroaromatic compounds having a pyridine ring, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB); 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1 ,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 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'-(triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine azine (abbreviation: mTpBPTzn), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3 heteroaromatic compounds containing heteroaromatic rings with a triazine ring, such as 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm ...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), 4,6mCzBP2Pm, 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4C z2PPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviated as 6BP-4Cz2PPm), 4-[3-(dibenzothiophen-4-yl)phenyl]-8-(naphthalen-2-yl)-[1]benzofuro[3,2-d]pyrimidine (abbreviated as 8βN-4mDBtPBfpm), 8BP-4mDBtPBfpm, 9mDBtB PNfpr, 9pmDBtBPNfpr, 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- and heteroaromatic compounds containing a heteroaromatic ring having a diazine (pyrimidine) ring, such as 8-[(2,2'-binaphthalen)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm). The aromatic compounds containing a heteroaromatic ring include heteroaromatic compounds having a fused heteroaromatic ring.

[0190] Other examples include 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 6,6'(P-Bqn)2BPy), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), and 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mB and heteroaromatic compounds containing a heteroaromatic ring having a triazine ring, such as 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviation: TmPPPyTz), 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tzn), and 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn).

[0191] Specific examples of the heteroaromatic compound having a fused ring structure partially containing a 6-membered ring structure (heteroaromatic compound having a fused ring structure) include bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2'-(1,3-phenylene)bis(9-furan), phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline 2-[3'-(9H-carbazol-9-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-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPD and heteroaromatic compounds having a quinoxaline ring, such as 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 7mDBTPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 6mDBTPDBq-II), 2mpPCBPDBq, etc.

[0192] In addition to the heteroaromatic compounds described above, the electron transport layers (114, 114a, 114b) may also include the following metal complexes: metal complexes having a quinoline ring or a benzoquinoline ring, such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq3), Almq3, 8-quinolinolato-lithium (abbreviation: Liq), BeBq2, bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), and bis(8-quinolinolato)zinc(II) (abbreviation: Znq); and metal complexes having an oxazole ring or a thiazole ring, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ).

[0193] In addition, polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) can also be used as electron transport materials.

[0194] The electron transport layer (114, 114a, 114b) may not only be a single layer, but also have a structure in which two or more layers made of the above-mentioned substances are stacked.

[0195] <Electron injection layer> The electron injection layers (115, 115a, 115b) are layers containing a substance with high electron injection properties. The electron injection layers (115, 115a, 115b) are layers for increasing the efficiency of electron injection from the second electrode 102, and it is preferable to use a material for the second electrode 102 having a work function whose difference in LUMO level is small (0.50 eV or less) compared with the LUMO level of the material for the electron injection layers (115, 115a, 115b). Therefore, the electron injection layer 115 may contain lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF), 8-quinolinolato-lithium (abbreviated as Liq), 2-(2-pyridyl)phenolatolithium (abbreviated as LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviated as LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviated as LiPPP), lithium oxide (LiO xAlkali metals, alkaline earth metals, or compounds thereof, such as cesium carbonate, can be used. Rare earth metals or rare earth metal compounds, such as erbium fluoride (ErF3) and ytterbium (Yb), can also be used. 1-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (abbreviation: 2hppSF), 1,1'-(9,9'-spirobi[9H-fluoren]-2,7-diyl)bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine, etc., can also be used. Compounds having a 1,3,4,6,7,8-tetrahydro-2H-pyrimido[1,2-a]pyrimidine skeleton, such as 1,3,4,6,7,8-tetrahydro-2H-pyrimido[1,2-a]pyrimidine (abbreviation: 2,7hpp2SF) and 1,1'-pyridine-2,6-diyl-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) (abbreviation: hpp2Py), can also be used. The electron injection layers (115, 115a, 115b) may be formed by mixing a plurality of the above materials or by stacking a plurality of the above materials. The electron injection layers (115, 115a, 115b) may also be formed by using an electride. Examples of electrides include a substance obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum. The substances constituting the electron transport layers (114, 114a, 114b) described above can also be used.

[0196] The electron injection layer (115, 115a, 115b) may also be made of a mixed material containing an organic compound and an electron donor (donor). Such a mixed material has 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, the electron transport materials (metal complexes, heteroaromatic compounds, etc.) used in the electron transport layer (114, 114a, 114b) described above 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, and rare earth metals are preferred, such as lithium, cesium, magnesium, calcium, erbium, and ytterbium. Alkali metal oxides and 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 (TTF) can also be used. Furthermore, a plurality of these materials may be laminated.

[0197] Alternatively, the electron injection layer (115, 115a, 115b) may be made of a mixed material containing an organic compound and a metal. The organic compound used here preferably has a LUMO level of -3.60 eV or more and -2.30 eV or less. A material having an unshared electron pair is also preferred.

[0198] Therefore, the organic compound used in the mixed material may be a mixed material obtained by mixing a heteroaromatic compound with a metal, as described above as being usable in the electron transport layer. Preferred heteroaromatic compounds include those having a five-membered ring structure (such as an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, or a benzimidazole ring), a six-membered ring structure (such as a pyridine ring, a diazine ring (including a pyrimidine ring, a pyrazine ring, or a pyridazine ring), a triazine ring, a bipyridine ring, or a terpyridine ring), or a fused ring structure partially including a six-membered ring structure (such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, or a phenanthroline ring). Specific materials are described above, so further explanation is omitted here.

[0199] As the metal used in the mixed material, it is preferable to use a transition metal belonging to Group 5, 7, 9 or 11 in the periodic table and a material belonging to Group 13, such as Ag, Cu, Al or In. In this case, the organic compound forms a half-occupied molecular orbital (SOMO) with the transition metal.

[0200] For example, when light obtained from the light-emitting layer 113b is to be amplified, the optical distance between the second electrode 102 and the light-emitting layer 113b is preferably set to be less than ¼ of the wavelength λ of the light emitted by the light-emitting layer 113b. In this case, the optical distance can be adjusted by changing the film thickness of the electron-transporting layer 114b or the electron-injecting layer 115b.

[0201] Furthermore, as in the light-emitting device shown in Figure 10(C), by providing a charge generation layer 106 between two EL layers (103a, 103b), a structure in which multiple EL layers are stacked between a pair of electrodes (also called a tandem structure) can be formed.

[0202] <Charge generation layer> The charge generation layers (106, 106a, 106b) have the function of injecting electrons into the EL layer 103a and injecting holes into the EL layer 103b when a voltage is applied between the first electrode (anode) 101 and the second electrode (cathode) 102. The charge generation layers (106, 106a, 106b) may be configured with a hole transport material to which an electron acceptor has been added (also referred to as a P-type layer) or with an electron transport material to which an electron donor has been added (also referred to as an electron injection buffer layer). Alternatively, both of these configurations may be stacked. Furthermore, an electron relay layer may be provided between the P-type layer and the electron injection buffer layer. By forming the charge generation layers (106, 106a, 106b) using the above-mentioned materials, it is possible to suppress an increase in driving voltage when EL layers are stacked.

[0203] When the charge generation layer (106, 106a, 106b) has a structure (P-type layer) in which an electron acceptor is added to an organic hole-transporting material, the material described in this embodiment can be used as the hole-transporting material. Examples of the electron acceptor include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ) and chloranil. Examples of the electron acceptor include oxides of metals belonging to Groups 4 to 8 of the periodic table. Specific examples include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide. The acceptor materials described above may also be used. Materials for the P-type layer may be mixed together to form a mixed film, or single films containing each material may be stacked.

[0204] Furthermore, when the charge generation layer (106, 106a, 106b) has a structure in which an electron donor is added to an electron transport material (electron injection buffer layer), the materials described in this embodiment can be used as the electron transport material. Furthermore, alkali metals, alkaline earth metals, rare earth metals, metals belonging to Groups 2 and 13 of the periodic table, and oxides and carbonates thereof can be used as the electron donor. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide (LiO), cesium carbonate, and the like are preferably used. Furthermore, an alkali metal compound such as Liq can also be used. Furthermore, an organic compound such as tetrathianaphthacene can also be used as the electron donor. Alternatively, organic compounds having a 1,3,4,6,7,8-tetrahydro-2H-pyrimido[1,2-a]pyrimidine skeleton, such as 2hppSF, 2,7hpp2SF, and hpp2Py, may be used as electron donors. When using these organic compounds as electron donors, it is preferable to combine them with electron transport materials containing a heteroaromatic ring having a phenanthroline ring, such as bathophenanthroline (abbreviated as Bphen), bathocuproine (abbreviated as BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBphen), or 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as mPPhen2P), because this reduces the driving voltage of light-emitting devices.

[0205] When an electron relay layer is provided between the P-type layer and the electron injection buffer layer in the charge generation layer (106, 106a, 106b), the electron relay layer contains at least a substance having electron transport properties and has the function of preventing interaction between the electron injection buffer layer and the P-type layer and smoothly transferring electrons. The LUMO level of the substance having electron transport properties contained in the electron relay layer is preferably between the LUMO level of the acceptor substance in the P-type layer and the LUMO level of the substance having electron transport properties contained in the electron transport layer in contact with the charge generation layer 106. The LUMO level of the substance having electron transport properties used in the electron relay layer is specifically −5.00 eV or higher, preferably −5.00 eV or higher and −3.00 eV or lower. Note that the substance having electron transport properties used in the electron relay layer is preferably a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0206] In terms of light extraction efficiency, the charge generation layers (106, 106a, 106b) preferably have transparency to visible light (specifically, the visible light transmittance of the charge generation layers (106, 106a, 106b) is 40% or more). Furthermore, the charge generation layers (106, 106a, 106b) function even if they have lower conductivity than the first electrode 101 and the second electrode 102.

[0207] Although FIG. 10C shows a structure in which the EL layer 103 has two stacked layers, a stacked structure of three or more EL layers may be used by providing a charge generating layer between different EL layers.

[0208] <Cap layer> 10A to 10E, a capping layer may be provided on the second electrode 102 of the light-emitting device. For example, a material with a high refractive index can be used for the capping layer. By providing the capping layer on the second electrode 102, the extraction efficiency of light emitted from the second electrode 102 can be improved.

[0209] Specific examples of materials that can be used for the cap layer include 5,5'-diphenyl-2,2'-di-5H-[1]benzothieno[3,2-c]carbazole (abbreviation: BisBTc) and 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II).

[0210] <Substrate> The light-emitting device described in this embodiment mode can be formed on various substrates. Note that the type of substrate is not limited to a specific one. Examples of the substrate include a semiconductor substrate (for example, a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate having stainless steel foil, a tungsten substrate, a substrate having tungsten foil, a flexible substrate, a laminated film, paper containing a fibrous material, or a base film.

[0211] Examples of glass substrates include barium borosilicate glass, aluminoborosilicate glass, soda lime glass, etc. Examples of flexible substrates, laminated films, base films, etc. include plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES), synthetic resins such as acrylic resins, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyamide, polyimide, aramid, epoxy resins, inorganic vapor deposition films, and papers.

[0212] Note that the light-emitting device described in this embodiment can be fabricated by a gas phase method such as vapor deposition, a spin coating method, or a liquid phase method such as an inkjet method. When a vapor deposition method is used, a physical vapor deposition (PVD) method such as sputtering, ion plating, ion beam deposition, molecular beam deposition, or vacuum deposition, or a chemical vapor deposition (CVD) method can be used. In particular, layers having various functions included in the EL layer of the light-emitting device (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, and electron injection layer 115) can be formed by a vapor deposition method (vacuum deposition, etc.), a coating method (dip coating, die coating, bar coating, spin coating, spray coating, etc.), a printing method (inkjet printing, screen (stencil printing), offset (lithographic printing), flexography (relief printing), gravure printing, microcontact printing, etc.), or the like.

[0213] When applying the above-mentioned coating method, printing method, or other film formation method, it is possible to use high molecular weight compounds (oligomers, dendrimers, polymers, etc.), medium molecular weight compounds (compounds in the intermediate range between low molecular weight and high molecular weight: molecular weight of 400 to 4000), inorganic compounds (quantum dot materials, etc.), etc. As quantum dot materials, colloidal quantum dot materials, alloy-type quantum dot materials, core-shell type quantum dot materials, core-type quantum dot materials, etc. can be used.

[0214] The layers constituting the EL layer 103 of the light-emitting device described in this embodiment (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, and electron injection layer 115) are not limited to the materials described in this embodiment, and other materials can be used in combination as long as they can fulfill the functions of each layer.

[0215] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0216] (Fourth embodiment) In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0217] The display device of the present embodiment can be a high-definition display device, and can therefore be used as a display unit for information terminals (wearable devices) such as wristwatches and bracelets, as well as for wearable devices that can be worn on the head, such as VR devices such as head-mounted displays (HMDs) and AR devices such as glasses.

[0218] The display device of this embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of this 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 display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproducing devices.

[0219] [Display module] 11A shows a perspective view of the display module 280. The display module 280 includes the display device 100A and an FPC 290.

[0220] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display unit 281. The display unit 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 unit 284 (described later) can be viewed.

[0221] 11(B) is a perspective view schematically showing 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 an 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.

[0222] The pixel section 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of Fig. 11(B). The various structures described in the previous embodiments can be applied to the pixel 284a. Fig. 11(B) shows an example in which the pixel 284a has the same structure as the pixel 110 shown in Fig. 1(A).

[0223] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0224] One pixel circuit 283a is a circuit that controls the driving of multiple elements included in one pixel 284a. One pixel circuit 283a can be configured to have three circuits that control the light emission of one light-emitting device. For example, the pixel circuit 283a can be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitor for each light-emitting device. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to the source. This realizes an active matrix display device.

[0225] The circuit portion 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 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.

[0226] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit section 282. An IC may also be mounted on the FPC 290.

[0227] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are provided overlapping below the pixel unit 284, thereby enabling the aperture ratio (effective display area ratio) of the display unit 281 to be extremely high. For example, the aperture ratio of the display unit 281 can be set to 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. Furthermore, the pixels 284a can be arranged at an extremely high density, enabling the resolution of the display unit 281 to be extremely high. For example, it is preferable that the pixels 284a are arranged in the display unit 281 at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20000 ppi or less, or 30000 ppi or less.

[0228] Such a display module 280 has extremely high resolution and can therefore be suitably used in VR devices such as HMDs or glasses-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 when the display unit is enlarged with the lenses, 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. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0229] [Display device 100B] The display device 100B shown in FIG. 12 includes a substrate 301, a light emitting device 10R, a light emitting device 10G, a light emitting device 10B, and a transistor 310.

[0230] The subpixel 50R shown in FIG. 11(B) has a light-emitting device 10R, the subpixel 50G has a light-emitting device 10G, and the subpixel 50B has a light-emitting device 10B.

[0231] 11A and 11B. The stacked structure from the substrate 301 to the insulating layer 255c corresponds to the layer 121 including the transistor in Embodiment 1.

[0232] The transistor 310 has a channel formation region in a 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 either a source or a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0233] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0234] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided on the insulating layer 261 .

[0235] Capacitor 240 has conductive layer 241, conductive layer 245, and insulating layer 243 located therebetween. Conductive layer 241 functions as one electrode of capacitor 240, conductive layer 245 functions as the other electrode of capacitor 240, and insulating layer 243 functions as a dielectric of capacitor 240.

[0236] 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 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.

[0237] Note that at least one of the conductive layers included in the layer 121 including the transistor preferably includes a conductive layer surrounding the outside of the display portion 281 (or the pixel portion 284). The conductive layer may also be called a guard ring. By providing the conductive layer, it is possible to prevent elements such as transistors and light-emitting devices from being damaged by high voltage applied to these elements due to charging caused by electrostatic discharge (ESD) or plasma-based processes.

[0238] An insulating layer 255a is provided covering the capacitor 240, an insulating layer 255b is provided on the insulating layer 255a, and an insulating layer 255c is provided on the insulating layer 255b. The light-emitting devices 10R, 10G, and 10B are provided on the insulating layer 255c.

[0239] The anodes of the light-emitting devices 10R, 10G, and 10B are electrically connected to one of the source and drain of the transistor 310 via a plug 256 embedded in the insulating layer 243, the insulating layer 255a, the insulating layer 255b, and the insulating layer 255c, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. The height of the surface of the insulating layer 255c that contacts the anode and the height of the surface of the plug 256 that contacts the anode are the same or approximately the same. Various conductive materials can be used for the plug.

[0240] In addition, a protective layer 122 is provided on the light-emitting devices 10R, 10G, and 10B. A substrate 124 is bonded to the protective layer 122 with a resin layer 123. For details of the components from the light-emitting devices to the substrate 124, refer to Embodiment 1. The substrate 124 corresponds to the substrate 292 in FIG. 11(A).

[0241] At least one of an insulating film, a semiconductor film, and a conductive film can be used as the protective layer 122. The protective layer 122 having an inorganic film can prevent oxidation of the cathode, suppress impurities (such as moisture and oxygen) from entering the light-emitting device, and suppress deterioration of the light-emitting device, thereby improving the reliability of the display device.

[0242] For example, an inorganic insulating film such as an insulating oxide film, an insulating nitride film, an insulating oxynitride film, or an insulating nitride oxide film can be used for the protective layer 122. Specific examples of these inorganic insulating films will be given in the description of the insulating layer 125. In particular, the protective layer 122 preferably has an insulating nitride film or an insulating nitride oxide film, and more preferably has an insulating nitride film.

[0243] The resin layer 123 can be made of various curable adhesives, such as a photo-curable adhesive (e.g., an ultraviolet curable adhesive), a reactive curable adhesive, a thermosetting adhesive, or an anaerobic adhesive. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. In particular, a material with low moisture permeability, such as epoxy resin, is preferable. Alternatively, a two-component resin may be used. Alternatively, an adhesive sheet or the like may be used.

[0244] The substrate 124 can be made of glass, quartz, ceramics, sapphire, resin, metal, alloy, semiconductor, or the like. A material that transmits light is used for the substrate on the side from which light from the light-emitting device is extracted. If a flexible material is used, the flexibility of the display device can be increased. A polarizing plate or the like may also be used. In this way, various materials can be used for the substrate.

[0245] Furthermore, the substrate 124 may be made of polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. The substrate 124 may be made of glass having a thickness sufficient to provide flexibility.

[0246] An inorganic insulating film is preferably used as the insulating layer 125. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. Alternatively, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may also be used.

[0247] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Furthermore, either a top-gate transistor or a bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0248] The crystallinity of the semiconductor material used for the transistor is not particularly limited, and any of an amorphous semiconductor, a single crystalline semiconductor, and a semiconductor having crystallinity other than single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single crystalline semiconductor or a crystalline semiconductor is preferable because it can suppress deterioration of the transistor characteristics.

[0249] The semiconductor layer of the transistor preferably includes a metal oxide (also referred to as an oxide semiconductor). That is, the display device of this embodiment preferably includes a transistor using a metal oxide for a channel formation region (hereinafter referred to as an OS transistor).

[0250] Examples of crystalline oxide semiconductors include c-axis-aligned crystalline (CAAC)-OS and nanocrystalline (nc)-OS.

[0251] Alternatively, a transistor using silicon in a channel formation region (Si transistor) may be used. Examples of silicon include single crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, a transistor having low temperature polysilicon (LTPS) in a semiconductor layer (hereinafter also referred to as an LTPS transistor) may be used. LTPS transistors have high field-effect mobility and good frequency characteristics.

[0252] By using Si transistors such as LTPS transistors, circuits that need to be driven at high frequencies (such as source driver circuits) can be built on the same substrate as the display unit, which simplifies the external circuits mounted on the display device and reduces component and mounting costs.

[0253] OS transistors have significantly higher field-effect mobility than transistors using amorphous silicon. Furthermore, OS transistors have significantly lower source-drain leakage current in an off state (hereinafter also referred to as off-state current), allowing them to retain charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of OS transistors can reduce the power consumption of display devices.

[0254] Furthermore, to increase the light emission luminance of a light-emitting device included in a pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting device. To achieve this, it is necessary to increase the source-drain voltage of the drive transistor included in the pixel circuit. Because OS transistors have a higher source-drain breakdown voltage than Si transistors, a high voltage can be applied between the source and drain of an OS transistor. Therefore, by using an OS transistor as the drive transistor included in a pixel circuit, it is possible to increase the amount of current flowing through the light-emitting device and increase the light emission luminance of the light-emitting device.

[0255] Furthermore, when the transistor operates in the saturation region, OS transistors can reduce the change in source-drain current relative to a change in gate-source voltage compared to Si transistors. Therefore, by using OS transistors as the drive transistors in pixel circuits, the current flowing between the source and drain can be precisely controlled by changing the gate-source voltage, thereby controlling the amount of current flowing through the light-emitting device. This allows for a wider range of gradations in the pixel circuit.

[0256] Furthermore, in terms of the saturation characteristics of the current that flows when a transistor operates in the saturation region, an OS transistor can pass a more stable current (saturation current) than a Si transistor, even when the source-drain voltage gradually increases. Therefore, by using an OS transistor as a drive transistor, for example, a stable current can be passed through a light-emitting device even when the current-voltage characteristics of the light-emitting device vary. In other words, when an OS transistor operates in the saturation region, the source-drain current remains almost unchanged even when the source-drain voltage increases, thereby stabilizing the light-emitting brightness of the light-emitting device.

[0257] As described above, by using an OS transistor for the drive transistor included in the pixel circuit, it is possible to achieve "suppression of black floating," "increase in light emission brightness," "multiple gradations," and "suppression of variation in light-emitting devices."

[0258] The semiconductor layer preferably contains, for example, indium, M (wherein M is one or more elements selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more elements selected from aluminum, gallium, yttrium, and tin.

[0259] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) for the semiconductor layer. Alternatively, it is preferable to use an oxide containing indium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), and zinc (Zn) (also referred to as IAZO). Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), gallium (Ga), and zinc (Zn) (also referred to as IAGZO). Alternatively, it is preferable to use indium oxide.

[0260] When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. The atomic ratio of metal elements in such an In-M-Zn oxide may be In:M:Zn=1:1:1 or a composition thereabout, In:M:Zn=1:1:1.2 or a composition thereabout, In:M:Zn=1:3:2 or a composition thereabout, In:M:Zn=1:3:4 or a composition thereabout, In:M:Zn=2:1:3 or a composition thereabout, In:M:Zn=3:1:2 or a composition thereabout, or In:M:Zn=4:2:3. or a composition in the vicinity thereof, In:M:Zn=4:2:4.1 or a composition in the vicinity thereof, In:M:Zn=5:1:3 or a composition in the vicinity thereof, In:M:Zn=5:1:6 or a composition in the vicinity thereof, In:M:Zn=5:1:7 or a composition in the vicinity thereof, In:M:Zn=5:1:8 or a composition in the vicinity thereof, In:M:Zn=6:1:6 or a composition in the vicinity thereof, In:M:Zn=5:2:5 or a composition in the vicinity thereof, etc. Note that a composition in the vicinity thereof includes a range of ±30% of the desired atomic ratio.

[0261] For example, when describing a composition with an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, this includes a case where, when In is taken as 4, Ga is 1 to 3 and Zn is 2 to 4. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, this includes a case where, when In is taken as 5, Ga is greater than 0.1 and 2 or less and Zn is 5 to 7 or less. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, this includes a case where, when In is taken as 1, Ga is greater than 0.1 and 2 or less and Zn is greater than 0.1 and 2 or less.

[0262] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0263] (Embodiment 5) In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS.

[0264] 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 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.

[0265] 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.

[0266] 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 (head-mounted displays), AR glasses-type devices, and MR glasses-type devices.

[0267] The display device of one embodiment of the present invention preferably has an extremely high resolution such as HD (1280 × 720 pixels), FHD (1920 × 1080 pixels), WQHD (2560 × 1440 pixels), WQXGA (2560 × 1600 pixels), 4K (3840 × 2160 pixels), or 8K (7680 × 4320 pixels). A resolution of 4K, 8K, or higher is particularly preferable. Furthermore, the pixel density (resolution) of the display device of one embodiment of the present invention is preferably 100 ppi or higher, preferably 300 ppi or higher, more preferably 500 ppi or higher, more preferably 1000 ppi or higher, more preferably 2000 ppi or higher, more preferably 3000 ppi or higher, more preferably 5000 ppi or higher, and even more preferably 7000 ppi or higher. By using a display device having either or both of high resolution and high definition, it is possible to further enhance the sense of realism and depth in electronic devices for personal use such as portable or home use. Furthermore, the screen ratio (aspect ratio) of the display device of one embodiment of the present invention is not particularly limited. For example, the display device can support various screen ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0268] The electronic device of this embodiment may have a sensor (including the function of sensing, detecting, or measuring 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 light).

[0269] The electronic device of the present embodiment can have various functions, such as a function to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date, time, etc., a function to execute various software (programs), a wireless communication function, a function to read out programs or data recorded on a recording medium, etc.

[0270] 13(A) to 13(D), an example of a wearable device that can be worn on the head will be described. These wearable devices have at least one of the following functions: a function to display AR content, a function to display VR content, a function to display SR content, and a function to display MR content. By having an electronic device have the function to display at least one of AR, VR, SR, and MR content, it is possible to enhance the user's sense of immersion.

[0271] The electronic device 700A shown in FIG. 13(A) and the electronic device 700B shown in FIG. 13(B) 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.

[0272] The display device of one embodiment of the present invention can be applied to the display panel 751. Therefore, the electronic device can display images with extremely high resolution.

[0273] Electronic device 700A and electronic device 700B can each project an image displayed on display panel 751 onto display area 756 of optical member 753. Because optical member 753 is translucent, the user can see the image displayed in the display area superimposed on a transmitted image visually recognized through optical member 753. Therefore, electronic device 700A and electronic device 700B are each electronic devices capable of AR display.

[0274] Electronic device 700A and electronic device 700B may be provided with a camera capable of capturing an image in front of them as an imaging unit. Furthermore, electronic device 700A and 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 display area 756.

[0275] The communication unit has a wireless communication device, and can supply a video signal, etc. 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 are supplied may be provided.

[0276] Furthermore, the electronic device 700A and the electronic device 700B are provided with batteries, which can be charged wirelessly and / or by wire.

[0277] The housing 721 may be provided with a touch sensor module. The touch sensor module has a function of detecting a touch on the outer surface of the housing 721. The touch sensor module can detect a tap operation or a slide operation by the user and perform various processes. For example, a tap operation can perform a process such as pausing or resuming a video, and a slide operation can perform a process such as fast-forwarding or fast-rewinding. Furthermore, providing a touch sensor module on each of the two housings 721 can expand the range of operations.

[0278] 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, and an optical type. In particular, it is preferable to use a capacitance type or an optical type sensor in the touch sensor module.

[0279] When an optical touch sensor is used, a photoelectric conversion device (also called a photoelectric conversion element) can be used as the light receiving device. The active layer of the photoelectric conversion device can be made of either or both of an inorganic semiconductor and an organic semiconductor.

[0280] The electronic device 800A shown in Figure 13(C) and the electronic device 800B shown in Figure 13(D) 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.

[0281] The display device of one embodiment of the present invention can be applied to the display portion 820. Therefore, an electronic device capable of displaying images with extremely high resolution can be provided, which allows a user to feel a high sense of immersion.

[0282] Display unit 820 is provided inside housing 821 at a position that can be viewed through lens 832. Also, by displaying different images on the pair of display units 820, it is possible to perform a three-dimensional display using parallax.

[0283] Electronic device 800A and electronic device 800B can each be said to be electronic devices for VR. A user wearing electronic device 800A or electronic device 800B can view an image displayed on display unit 820 through lens 832.

[0284] It is preferable that electronic device 800A and electronic device 800B each have a mechanism that can adjust the left and right positions of lens 832 and display unit 820 so that they are optimally positioned according to the position of the user's eyes. It is also preferable that electronic device 800A and electronic device 800B each have a mechanism that can adjust the focus by changing the distance between lens 832 and display unit 820.

[0285] The mounting unit 823 allows the user to mount the electronic device 800A or the electronic device 800B on the head. Note that, in Fig. 13(C) and other figures, the mounting unit 823 is shaped like the temples of glasses (also called joints or temples), but is not limited to this. The mounting unit 823 may be shaped like a helmet or a band, for example, as long as it can be worn by the user.

[0286] 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.

[0287] Although an example having the imaging unit 825 has been shown here, a distance measuring sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object may be provided. That is, the imaging unit 825 is one aspect of the detection unit. As the detection unit, for example, an image sensor or a range image sensor such as a LIDAR (Light Detection and Ranging) can be used. By using an image obtained by the camera and an image obtained by the range image sensor, more information can be obtained, enabling more accurate gesture operations.

[0288] Electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone. For example, a configuration having such a vibration mechanism can be applied to one or more of display unit 820, housing 821, and wearing unit 823. This allows a user to enjoy video and audio simply by wearing electronic device 800A, without the need for separate audio equipment such as headphones, earphones, or speakers.

[0289] The electronic device 800A and the electronic device 800B may each have an input terminal (also referred to as an input unit). The input terminal can be connected to a cable for supplying a video signal from a video output device or the like and power for charging a battery provided in the electronic device.

[0290] The electronic device of one embodiment of the present invention may have a function of wireless communication with an earphone 750. The earphone 750 has a communication unit (not shown) and has a wireless communication function. The earphone 750 can receive information (e.g., audio data) from the electronic device through the wireless communication function. For example, the electronic device 700A shown in FIG. 13A has a function of transmitting information to the earphone 750 through the wireless communication function. Furthermore, for example, the electronic device 800A shown in FIG. 13C has a function of transmitting information to the earphone 750 through the wireless communication function.

[0291] The electronic device may also have an earphone unit. Electronic device 700B shown in Fig. 13(B) has earphone unit 727. For example, earphone unit 727 and a control unit may be configured to be connected to each other by wire. Part of the wiring connecting earphone unit 727 and the control unit may be disposed inside housing 721 or wearing unit 723.

[0292] 13(D) includes an earphone unit 827. For example, the earphone unit 827 and the control unit 824 can be configured to be connected to each other by wire. A portion of the wiring connecting the earphone unit 827 and the control unit 824 may be disposed inside the housing 821 or the wearing unit 823. The earphone unit 827 and the wearing unit 823 may also have a magnet. This allows the earphone unit 827 to be fixed to the wearing unit 823 by magnetic force, which is preferable as it makes storage easier.

[0293] The electronic device may have an audio output terminal to which earphones or headphones can be connected. The electronic device may also have one or both of an audio input terminal and an audio input mechanism. For example, a sound collection device such as a microphone can be used as the audio input mechanism. By having the audio input mechanism, the electronic device may be endowed with the functionality of a so-called headset.

[0294] As described above, the electronic devices of one embodiment of the present invention are preferably either glasses-type devices (such as the electronic devices 700A and 700B) or goggle-type devices (such as the electronic devices 800A and 800B).

[0295] Furthermore, the electronic device of one embodiment of the present invention can transmit information to the earphone by wire or wirelessly.

[0296] An electronic device 6500 shown in FIG. 14A is a portable information terminal that can be used as a smartphone.

[0297] 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, and a light source 6508. The display portion 6502 has a touch panel function.

[0298] The display device of one embodiment of the present invention can be applied to the display portion 6502.

[0299] FIG. 14B is a schematic cross-sectional view including the end portion of the housing 6501 on the microphone 6506 side.

[0300] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 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.

[0301] 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).

[0302] In an area outside the display unit 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.

[0303] The display device of one embodiment of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. Furthermore, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted thereon while keeping the thickness of the electronic device small. Furthermore, 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.

[0304] 14C shows an example of a television set. A television set 7100 includes a display portion 7000 built in a housing 7101. Here, the housing 7101 is supported by a stand 7103.

[0305] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0306] 14C can be operated using operation switches provided on the housing 7101 and a separate remote control 7111. Alternatively, the display portion 7000 may be provided with a touch sensor, and the television set 7100 may be operated by touching the display portion 7000 with a finger or the like. The remote control 7111 may have a display portion that displays information output from the remote control 7111. Using operation keys or a touch panel provided on the remote control 7111, the channel and volume can be controlled, and an image displayed on the display portion 7000 can be controlled.

[0307] The television device 7100 is configured to include a receiver, a modem, and the like. The receiver can receive general television broadcasts. In addition, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0308] 14D 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, an external connection port 7214, and the like. A display portion 7000 is incorporated in the housing 7211.

[0309] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0310] 14(E) and 14(F) show an example of digital signage that can be used in a show window, a showcase, or the like.

[0311] 14E 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.

[0312] 14F 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.

[0313] In FIGS. 14E and 14F, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0314] 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.

[0315] In particular, when the display device of one embodiment of the present invention is used for advertisements or the like using the digital signage 7400 shown in Figure 14(F), 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.

[0316] Furthermore, by using the tandem light-emitting device according to one embodiment of the present invention in addition to the wiring and support member using the conductive film that transmits visible light, it is possible to increase the luminance per pixel. That is, even if the aperture ratio of the display device is reduced, good display is possible, and the light transmittance in the display portion of the display device can be increased. Therefore, the display device according to one embodiment of the present invention is suitable as a light-transmitting display device.

[0317] 14(E) and 14(F), the digital signage 7300 or the digital signage 7400 is preferably capable of wirelessly linking with an information terminal 7311 or an information terminal 7411 such as a smartphone carried by a user. For example, advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or the information terminal 7411. By operating the information terminal 7311 or the information terminal 7411, the display on the display unit 7000 can be switched.

[0318] Furthermore, the digital signage 7300 or the digital signage 7400 can be made to run a game using the screen of the information terminal 7311 or the information terminal 7411 as an operation means (controller), thereby allowing an unspecified number of users to simultaneously participate in and enjoy the game.

[0319] The electronic devices shown in Figures 15(A) to 15(G) have a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including a function to sense, detect, or measure force, displacement, position, speed, 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), a microphone 9008, etc.

[0320] 15(A) to 15(G) have various functions. For example, they may have a function to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date, or time, a function to control processing using various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. Note that the functions of the electronic devices are not limited to these, and they may have various other functions. The electronic devices may have multiple display units. Furthermore, the electronic devices may have a function to include a camera or the like to capture still images or videos and store them on a recording medium (external or built-in to the camera), a function to display the captured images on the display unit, etc.

[0321] The electronic devices shown in FIGS. 15A to 15G will be described in detail below.

[0322] FIG. 15A is a perspective view showing a mobile information terminal 9101. The mobile information terminal 9101 can be used as, for example, a smartphone. The mobile information terminal 9101 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, and the like. The mobile information terminal 9101 can display text and image information on multiple surfaces. FIG. 15A shows an example in which three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notifications of incoming calls, such as emails, SNS (social networking services, or social media), and phone calls, the title of the email or SNS, the sender's name, the date and time, the remaining battery level, and signal strength. Alternatively, an icon 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0323] 15B is a perspective view showing a mobile information terminal 9102. The mobile information terminal 9102 has a function of displaying information on three or more surfaces of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, a user can check information 9053 displayed in a position that can be observed from above the mobile information terminal 9102 while the mobile information terminal 9102 is placed in a breast pocket of clothes. The user can check the display without taking the mobile information terminal 9102 out of the pocket and decide, for example, whether to answer a call.

[0324] 15C is a perspective view of a tablet terminal 9103. The tablet terminal 9103 is capable of executing various applications such as mobile phone calls, e-mails, text browsing and creation, music playback, internet communication, and computer games, for example. The tablet terminal 9103 has a display portion 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front side of a housing 9000, operation keys 9005 as operation buttons on the left side of the housing 9000, and a connection terminal 9006 on the bottom.

[0325] FIG. 15D is a perspective view of a wristwatch-type mobile information terminal 9200. The mobile information terminal 9200 can be used as, for example, a smart watch (registered trademark). The mobile information terminal 9200 may include operation keys 9005 as operation buttons on the left side of the housing 9000 and a sensor 9007 on the bottom. Although the curved bangle-type housing 9000 is shown as an example, the housing 9000 may be attached to a belt or the like. The display surface of the display unit 9001 is curved, and a display can be performed along the curved display surface. The power storage device 9004 may be curved along the housing 9000. The power storage device 9004 is flexible and can be bent according to a change in shape when attached or detached. A charge control IC connected to the power storage device 9004 may be included. The mobile information terminal 9200 can also perform hands-free conversation by communicating with, for example, a headset capable of wireless communication. The portable information terminal 9200 can also wirelessly transmit data to and from other information terminals and can be charged by wireless power supply. Note that the data transmission and charging may be performed by wire using a connection terminal 9006 provided in the housing 9000.

[0326] 15(E) to 15(G) are perspective views showing a foldable mobile information terminal 9201. FIG. 15(E) shows the mobile information terminal 9201 in an unfolded state, FIG. 15(G) shows it in a folded state, and FIG. 15(F) is a perspective view showing a state in the process of changing from one of FIG. 15(E) and FIG. 15(G) to the other. The mobile information terminal 9201 is highly portable when folded, and has a seamless, wide display area when unfolded, providing excellent viewability of the display. A display portion 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display portion 9001 can be bent with a curvature radius of 0.1 mm to 150 mm.

[0327] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0328] (Embodiment 6) In this embodiment, a light-emitting device of one embodiment of the present invention will be described with reference to FIGS.

[0329] [Pixel layout] In this embodiment, pixel layouts different from that shown in FIG. 1A 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.

[0330] 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.

[0331] 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.

[0332] 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.

[0333] An S-stripe arrangement is applied to the pixel 110 shown in Fig. 16(A). The pixel 110 shown in Fig. 16(A) is composed of three subpixels: a subpixel 50R, a subpixel 50G, and a subpixel 50B.

[0334] The pixel 110 shown in FIG. 16(B) includes a subpixel 50R having a generally trapezoidal or triangular top surface shape with rounded corners, a subpixel 50G having a generally trapezoidal or triangular top surface shape with rounded corners, and a subpixel 50B having a generally rectangular or hexagonal top surface shape with rounded corners. The subpixel 50R has a larger light-emitting area than the subpixel 50G. Thus, 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.

[0335] The Pentile arrangement is applied to the pixels 110a and 110b shown in Fig. 16(C). Fig. 16(C) shows an example in which the pixel 110a having the subpixel 50R and the subpixel 50G and the pixel 110b having the subpixel 50G and the subpixel 50B are arranged alternately.

[0336] 16(D) to 16(F) are arranged in a delta configuration. Pixel 110a has two subpixels (subpixel 50R and subpixel 50G) in the top row (first row) and one subpixel (subpixel 50B) in the bottom row (second row). Pixel 110b has one subpixel (subpixel 50B) in the top row (first row) and two subpixels (subpixel 50R and subpixel 50G) in the bottom row (second row).

[0337] Figure 16(D) is an example in which each sub-pixel has an approximately rectangular top surface shape with rounded corners, Figure 16(E) is an example in which each sub-pixel has a circular top surface shape, and Figure 16(F) is an example in which each sub-pixel has an approximately hexagonal top surface shape with rounded corners.

[0338] In Figure 16(F), each subpixel is arranged inside a densely arranged hexagonal region. Each subpixel is arranged so that it is surrounded by six other subpixels when focusing on one subpixel. 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 50R, three subpixels 50G and three subpixels 50B are arranged alternately to surround it.

[0339] 16(G) 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 50R and 50G, or subpixels 50G and 50B) are misaligned.

[0340] 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.

[0341] This embodiment mode can be combined with other embodiment modes 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. [Explanation of symbols]

[0342] 10B Light-emitting devices 10G Light Emitting Device 10R Light Emitting Device 11B Anode 11G anode 11R Anode 11R_a Conductive material 11R_b Transparent conductive film 11G_a Conductive material 11G_b Transparent conductive film 11B_a Conductive material 11B_b Transparent conductive film 12_a First hole injection / transport layer 12_b Second hole injection / transport layer 13B_a First light-emitting layer 13B_b Third light-emitting layer 13G_a First light-emitting layer 13G_b second light-emitting layer 13R_a Second light-emitting layer 13R_b Fourth light-emitting layer 14_a First electron injection / transport layer 14_b Second electron injection / transport layer 15 Cathode 19_a Hole blocking layer 19_b Hole blocking layer 20_a Electron blocking layer 20_b Electron Blocking Layer 21 Middle Class 50B subpixel 50G subpixel 50R subpixel 100A display device 100B display device 100 display device 101 first electrode 102 second electrode 103a EL layer 103b EL layer 103 EL layer 106a Charge generation layer 106b Charge generation layer 106 Charge generation layer 110 pixels 110a pixels 110b pixels 111a Hole injection layer 111b Hole injection layer 111 Hole injection layer 112a Hole transport layer 112b hole transport layer 112 Hole transport layer 113a Light-emitting layer 113a_1 Light-emitting layer 113a_2 Light-emitting layer 113b Light-emitting layer 113b_1 Light-emitting layer 113b_2 Light-emitting layer 113c Light-emitting layer 113 Light-emitting layer 114b Electron transport layer 114 Electron transport layer 115b Electron injection layer 115 Electron injection layer 116 Electron Block Layer 117 Hole Blocking Layer 121 layers 122 Protective layer 123 Resin layer 124 board 125 Insulating Layer 140 Connection 136R colored layer 136B Colored layer 136G colored layer 137 Black Matrix 240 capacity 241 Conductive Layer 243 Insulating Layer 245 Conductive Layer 254 Insulating Layer 255a Insulating layer 255b insulating layer 255c insulating layer 256 plug 261 Insulating Layer 271 Plug 280 Display Module 281 Display section 282 Circuit section 283a Pixel circuit 283 Pixel circuit section 284a pixels 284 pixel section 285 Terminal section 286 Wiring section 290 FPC 291 Circuit Board 292 PCB 301 Substrate 310 Transistor 311 Conductive layer 312 Low resistance region 313 Insulating Layer 314 Insulating Layer 315 Element isolation layer 700A electronic equipment 700B Electronic equipment 721 Case 723 Mounting part 727 Earphones 750 earphones 751 Display Panel 753 Optical Components 756 Display area 757 frames 758 Nose pad 800A electronic equipment 800B Electronic equipment 820 Display section 821 Case 822 Communications Department 823 Mounting part 824 Control Unit 825 Imaging unit 827 Earphones 832 Lens 6500 Electronic equipment 6501 Housing 6502 Display section 6503 Power button 6504 Button 6505 Speaker 6506 Microphone 6507 Camera 6508 Light source 6510 Protective materials 6511 Display Panel 6512 Optical components 6513 Touch Sensor Panel 6515 FPC 6516 IC 6517 Printed Circuit Board 6518 Battery 7000 Display 7100 Television equipment 7101 Housing 7103 Stand 7111 Remote control device 7200 Notebook Personal Computer 7211 Case 7212 keyboard 7213 Pointing Device 7214 External connection port 7300 Digital Signage 7301 Housing 7303 Speaker 7311 Information terminals 7400 Digital Signage 7401 Pillar 7411 Information terminals 9000 chassis 9001 Display section 9002 Camera 9003 Speaker 9005 Operation key 9006 Connection terminal 9007 Sensor 9008 Microphone 9050 Icon 9051 Information 9052 Information 9053 Information 9054 Information 9055 Hinge 9101 Mobile Information Terminal 9102 Mobile Information Terminal 9103 Tablet device 9200 Mobile Information Terminal 9201 Mobile Information Terminal

Claims

1. a first sub-pixel, a second sub-pixel, and a third sub-pixel that emit light of different colors; the first subpixel includes a first colored layer and a first light-emitting device; the second subpixel has a second colored layer and a second light-emitting device; the third subpixel includes a third light-emitting device; the first light-emitting device has a first light-emitting layer and a second light-emitting layer between a pair of electrodes, and a first intermediate layer between the first light-emitting layer and the second light-emitting layer; the first light-emitting layer and the second light-emitting layer each include a layer containing a blue light-emitting material and a layer containing a red light-emitting material, the second light-emitting device has a third light-emitting layer and a fourth light-emitting layer between a pair of electrodes, and a second intermediate layer between the third light-emitting layer and the fourth light-emitting layer; the third light-emitting layer and the fourth light-emitting layer each include a layer containing a blue light-emitting material and a layer containing a red light-emitting material, the third light-emitting device has a fifth light-emitting layer and a sixth light-emitting layer between a pair of electrodes, and a third intermediate layer between the fifth light-emitting layer and the sixth light-emitting layer; The display device, wherein the fifth light-emitting layer and the sixth light-emitting layer are layers each containing a green light-emitting material.

2. a first sub-pixel and a second sub-pixel that emit light of different colors; the first subpixel includes a first colored layer and a first light-emitting device; the second subpixel has a second colored layer and a second light-emitting device; the first light-emitting device has a first light-emitting layer, a second light-emitting layer, a third light-emitting layer, a fourth light-emitting layer, and a first intermediate layer between a pair of electrodes; the first light-emitting layer is in contact with the second light-emitting layer, the third light-emitting layer is in contact with the fourth light-emitting layer, the first intermediate layer is located between the first light-emitting layer and the third light-emitting layer, and is located between the second light-emitting layer and the fourth light-emitting layer; the second light-emitting device has a fifth light-emitting layer, a sixth light-emitting layer, a seventh light-emitting layer, an eighth light-emitting layer, and a second intermediate layer between a pair of electrodes; the fifth light-emitting layer is in contact with the sixth light-emitting layer, the seventh light-emitting layer is in contact with the eighth light-emitting layer, the second intermediate layer is located between the fifth light-emitting layer and the seventh light-emitting layer, and is located between the sixth light-emitting layer and the eighth light-emitting layer; the first light-emitting layer and the fifth light-emitting layer contain a first light-emitting material; the second light-emitting layer and the sixth light-emitting layer contain a second light-emitting material; the third light-emitting layer and the seventh light-emitting layer contain the first light-emitting material; The fourth light-emitting layer and the eighth light-emitting layer contain the second light-emitting material.

3. In claim 2, the first luminescent material is a blue luminescent material; The display device, wherein the second luminescent material is a red luminescent material.

4. In claim 2, A display device, wherein the emission wavelength of one of the first luminescent material and the second luminescent material is 1.18 times or more and 1.88 times or less the emission wavelength of the other.

5. a first sub-pixel, a second sub-pixel, and a third sub-pixel that emit light of different colors; the first subpixel includes a first colored layer and a first light-emitting device; the second subpixel has a second colored layer and a second light-emitting device; the third subpixel includes a third light-emitting device; the first light-emitting device has a first light-emitting layer, a second light-emitting layer, a third light-emitting layer, a fourth light-emitting layer, and a first intermediate layer between a pair of electrodes; the first light-emitting layer is in contact with the second light-emitting layer, the third light-emitting layer is in contact with the fourth light-emitting layer, the first intermediate layer is located between the first light-emitting layer and the third light-emitting layer, and is located between the second light-emitting layer and the fourth light-emitting layer; the second light-emitting device has a fifth light-emitting layer, a sixth light-emitting layer, a seventh light-emitting layer, an eighth light-emitting layer, and a second intermediate layer between a pair of electrodes; the fifth light-emitting layer is in contact with the sixth light-emitting layer, the seventh light-emitting layer is in contact with the eighth light-emitting layer, the second intermediate layer is located between the fifth light-emitting layer and the seventh light-emitting layer, and is located between the sixth light-emitting layer and the eighth light-emitting layer; the third light-emitting device has a ninth light-emitting layer, a tenth light-emitting layer, and a third intermediate layer between a pair of electrodes; the third intermediate layer is located between the ninth light-emitting layer and the tenth light-emitting layer; the first light-emitting layer and the fifth light-emitting layer contain a first light-emitting material; the second light-emitting layer and the sixth light-emitting layer contain a second light-emitting material; the third light-emitting layer and the seventh light-emitting layer contain the first light-emitting material; the fourth light-emitting layer and the eighth light-emitting layer contain the second light-emitting material; The ninth light-emitting layer and the tenth light-emitting layer comprise a third light-emitting material.

6. In claim 5, the first luminescent material is a blue luminescent material; the second luminescent material is a red luminescent material; The display device, wherein the third luminescent material is a green luminescent material.

7. In any one of claims 2 to 6, the first luminescent material is a fluorescent luminescent material; The display device, wherein the second light-emitting material is a phosphorescent light-emitting material.

8. In any one of claims 2 to 6, the first luminescent material is a fluorescent luminescent material; the second luminescent material is a phosphorescent luminescent material; the first light-emitting layer comprises a first host material; T of the first host material １ level and the T of the first luminescent material １ The level is the T １ A display device that is higher than the level.

9. In any one of claims 1 to 6, A display device, wherein the first intermediate layer and the second intermediate layer each include an organic compound and an alkali metal or an alkaline earth metal.

10. In any one of claims 1 to 6, A display device, wherein the first intermediate layer and the second intermediate layer each contain the same organic compound and the same alkali metal or alkaline earth metal.

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