Light-emitting device

Abstract

An organic semiconductor device with high image sharpness and high reliability is provided. One of a plurality of light-emitting devices is provided, which are formed by a photolithography method over an insulating layer; and the light-emitting devices include an organic compound-containing layer between a pair of electrodes; the organic compound-containing layer includes a light-emitting layer containing an emission center substance and a first substance; and the absorption edge having the longest wavelength in an absorption spectrum of the first substance is located at a wavelength shorter than 400 nm, or the first substance does not contain a condensed ring formed of only six-membered rings.

Description

Technical area

[0001] One embodiment of the present invention relates to a light-emitting device.

[0002] Note that an embodiment of the present invention is not limited to the above technical field. Examples of the technical field of an embodiment of the present invention include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device (e.g., a touch sensor), an input / output device (e.g., a touch screen), an operation method thereof, and a manufacturing method thereof. State of the art

[0003] In recent years, display devices have been developed for a variety of applications. Large-scale display devices include home televisions (also known as TVs or television receivers), digital signage, and public information displays (PIDs). Small-scale display devices include touchscreen smartphones and touchscreen tablet devices.

[0004] At the same time, there is also a demand for increased resolution of display devices. Devices requiring high image sharpness include devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR).

[0005] Light-emitting devices (also referred to as light-emitting elements) are actively developed as display elements used in display devices. Light-emitting devices utilizing electroluminescence (hereinafter referred to as EL) phenomena (also referred to as EL devices or EL elements), particularly organic EL devices primarily using an organic compound, have features such as ease of reduction in thickness and weight, high response speed to input signals, and operable with a constant DC power source, and are therefore suitable for a display device.

[0006] Instead of an evaporation method using a metal mask, patterning an organic layer by a photolithography method using a photoresist or the like is being explored to obtain a high-definition light-emitting device using an organic EL device. By applying the photolithography method, a high-definition display device can be obtained in which the distance between EL layers is a few micrometers (see, for example, Patent Document 1). [Reference][Patent document]

[0007] [Patent Document 1] Japanese Patent Laid-Open PCT International Application No. 2018-521459 Summary of the inventionProblem to be solved by the invention

[0008] It has been previously known that the initial properties or reliability of an EL layer in an organic EL device is affected by exposure to atmospheric components such as water and oxygen. Therefore, it is common knowledge that the EL layer is processed in a near-vacuum atmosphere. However, in a processing step by a photolithography method described above, it is difficult to maintain a high vacuum state. Therefore, the reliability of a light-emitting device manufactured by a photolithography method is often lower than that of a light-emitting device manufactured in a near-vacuum atmosphere.

[0009] Therefore, an object of one embodiment of the present invention is to provide a high-reliability light-emitting device formed using an organic compound by a photolithography method. Another object of another embodiment of the present invention is to provide a light-emitting device capable of providing a light-emitting device with high image sharpness and high reliability.

[0010] Another object of an embodiment of the present invention is to provide a highly reliable, high-density light-emitting device. Another object of an embodiment of the present invention is to provide a highly reliable light-emitting device that can provide a display device with high image sharpness.

[0011] Another object of an embodiment of the present invention is to provide a display device with high display performance. Another object of an embodiment of the present invention is to provide a display device with high resolution and favorable display performance. Another object of an embodiment of the present invention is to provide a display device with favorable display quality and display performance.

[0012] A further object is to provide a novel display device, a novel display module and a novel electronic device.

[0013] It should be noted that the description of these objects does not preclude the existence of further objects. An embodiment of the present invention does not necessarily have to fulfill all of these objects. Further objects can be derived from the explanation of the description, the drawings, and the claims. Means to solve the problem

[0014] One embodiment of the present invention is a light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, wherein the group of light-emitting devices comprises a first electrode group formed over the same insulating surface, a second electrode facing the first electrode group, and a first layer group positioned between the first electrode group and the second electrode. The first electrode group comprises a plurality of first electrodes, each independent of each other for each of the plurality of light-emitting devices. The first layer group comprises a plurality of first layers, each independent of each other for each of the plurality of light-emitting devices.The second electrode is a continuous conductive layer shared by the plurality of light-emitting devices. The light-emitting device includes a first electrode of the first electrode group, the second electrode, and a first layer of the first layer group. The second electrode and the first layer overlap with the first electrode. The first layer includes a light-emitting layer containing an emission center substance and a first substance. A wavelength of an absorption edge having the longest wavelength in an absorption spectrum of the first substance is shorter than 400 nm. A distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm.

[0015] Another embodiment of the present invention is a light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, wherein the group of light-emitting devices comprises a first electrode group formed over the same insulating surface, a second electrode facing the first electrode group, and a first layer group positioned between the first electrode group and the second electrode. The first electrode group comprises a plurality of first electrodes, each independent of each other for each of the plurality of light-emitting devices. The first layer group comprises a plurality of first layers, each independent of each other for each of the plurality of light-emitting devices.The second electrode is a continuous conductive layer shared by the plurality of light-emitting devices. The light-emitting device includes a first electrode of the first electrode group, the second electrode, and a first layer of the first layer group. The second electrode and the first layer overlap with the first electrode. The first layer includes a light-emitting layer containing an emission center substance and a first substance. The first substance does not include a condensed ring formed only of six-membered rings. A distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm.

[0016] Another embodiment of the present invention is a light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, wherein the group of light-emitting devices comprises a first electrode group formed over the same insulating surface, a second electrode facing the first electrode group, and a first layer group positioned between the first electrode group and the second electrode. The first electrode group comprises a plurality of first electrodes, each independent of each other for each of the plurality of light-emitting devices. The first layer group comprises a plurality of first layers, each independent of each other for each of the plurality of light-emitting devices.The second electrode is a continuous conductive layer shared by the plurality of light-emitting devices. The light-emitting device includes a first electrode of the first electrode group, the second electrode, and a first layer of the first layer group. The second electrode and the first layer overlap with the first electrode. The first layer includes a light-emitting layer containing an emission center substance and a first substance. The first substance has neither a structure in which two adjacent six-membered aromatic rings are condensed, nor a structure in which two adjacent six-membered heteroaromatic rings are condensed, nor a structure in which a six-membered aromatic ring and a six-membered heteroaromatic ring that are adjacent to each other are condensed.A distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm.

[0017] Another embodiment of the present invention is a light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, wherein the group of light-emitting devices comprises a first electrode group formed over the same insulating surface, a second electrode facing the first electrode group, and a first layer group positioned between the first electrode group and the second electrode. The first electrode group comprises a plurality of first electrodes, each independent of each other for each of the plurality of light-emitting devices. The first layer group comprises a plurality of first layers, each independent of each other for each of the plurality of light-emitting devices.The second electrode is a continuous conductive layer shared by the plurality of light-emitting devices. The light-emitting device includes a first electrode of the first electrode group, the second electrode, and a first layer of the first layer group. The second electrode and the first layer overlap with the first electrode. The first layer includes a light-emitting layer containing an emission center substance and a first substance. The first substance does not have a naphthalene structure. A distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm.

[0018] Another embodiment of the present invention is a light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, wherein the group of light-emitting devices comprises a first electrode group formed over the same insulating surface, a second electrode facing the first electrode group, and a first layer group positioned between the first electrode group and the second electrode. The first electrode group comprises a plurality of first electrodes, each independent of each other for each of the plurality of light-emitting devices. The first layer group comprises a plurality of first layers, each independent of each other for each of the plurality of light-emitting devices.The second electrode is a continuous conductive layer shared by the plurality of light-emitting devices. The light-emitting device includes a first electrode of the first electrode group, the second electrode, and a first layer of the first layer group. The second electrode and the first layer overlap with the first electrode. The first layer includes a light-emitting layer containing an emission center substance and a first substance. The first substance does not include a naphthalene ring, a phenanthrene ring, or a naphthacene ring. A distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm.

[0019] Another embodiment of the present invention is a light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, wherein the group of light-emitting devices comprises a first electrode group formed over the same insulating surface, a second electrode facing the first electrode group, and a first layer group positioned between the first electrode group and the second electrode. The first electrode group comprises a plurality of first electrodes, each independent of each other for each of the plurality of light-emitting devices. The first layer group comprises a plurality of first layers, each independent of each other for each of the plurality of light-emitting devices.The second electrode is a continuous conductive layer shared by the plurality of light-emitting devices. The light-emitting device includes a first electrode of the first electrode group, the second electrode, and a first layer of the first layer group. The second electrode and the first layer overlap with the first electrode. The first layer includes a light-emitting layer containing an emission center substance and a first substance. The first substance includes a condensed ring. The condensed ring is formed of fewer than 10 elements. A distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm.

[0020] Another embodiment of the present invention is a light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, wherein the group of light-emitting devices comprises a first electrode group formed over the same insulating surface, a second electrode facing the first electrode group, and a first layer group positioned between the first electrode group and the second electrode. The first electrode group comprises a plurality of first electrodes, each independent of each other for each of the plurality of light-emitting devices. The first layer group comprises a plurality of first layers, each independent of each other for each of the plurality of light-emitting devices.The second electrode is a continuous conductive layer shared by the plurality of light-emitting devices. The light-emitting device includes a first electrode of the first electrode group, the second electrode, and a first layer of the first layer group. The second electrode and the first layer overlap with the first electrode. The first layer includes a light-emitting layer containing an emission center substance and a first substance. The first substance includes a condensed ring. In the condensed ring, a six-membered ring and a five-membered ring are alternately condensed. A distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm.

[0021] Another embodiment of the present invention is a light-emitting device having the above structure, in which a wavelength of an absorption edge having the longest wavelength in an absorption spectrum of the first substance is shorter than 400 nm.

[0022] Another embodiment of the present invention is a light-emitting device having the above structure, in which a wavelength of an absorption edge having the longest wavelength in an absorption spectrum of the light-emitting substance is longer than or equal to 400 nm.

[0023] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the first substance does not absorb light having a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm.

[0024] Another embodiment of the present invention is a light-emitting device having the above structure, in which the light-emitting substance absorbs light having a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm.

[0025] Another embodiment of the present invention is a light-emitting device having the above structure, wherein a difference between a wavelength of an absorption edge having the longest wavelength in an absorption spectrum of the light-emitting substance and a wavelength of an absorption edge having the longest wavelength in an absorption spectrum of the first substance is greater than or equal to 60 nm.

[0026] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the first layer contains a second substance, and the second substance has a structure having the same feature as the feature described as a feature of the structure of the first substance.

[0027] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the first layer contains a second substance and a wavelength of an absorption edge having the longest wavelength in an absorption spectrum of the second substance is shorter than 400 nm.

[0028] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the first layer contains a second substance, and the second substance does not comprise a condensed ring formed only of six-membered rings.

[0029] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the first layer contains a second substance, and the second substance has neither a structure in which two adjacent six-membered aromatic rings are condensed, nor a structure in which two adjacent six-membered heteroaromatic rings are condensed, nor a structure in which a six-membered aromatic ring and a six-membered heteroaromatic ring that are adjacent to each other are condensed.

[0030] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the first layer contains a second substance and the second substance does not have a naphthalene structure.

[0031] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the first layer contains a second substance, and the second substance does not comprise a naphthalene ring, a phenanthrene ring, or a naphthacene ring.

[0032] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the first layer contains a second substance, the second substance comprises a condensed ring, and the condensed ring is formed of less than 10 elements.

[0033] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the first layer contains a second substance, the second substance comprises a condensed ring, and the condensed ring has a structure in which a six-membered ring and a five-membered ring are alternately condensed.

[0034] Another embodiment of the present invention is a light-emitting device having the above structure, in which one of the first substance and the second substance transports electrons and the other transports holes.

[0035] Another embodiment of the present invention is a light-emitting device having the above structure, wherein one of the first substance and the second substance is an organic compound having a π-electron-rich heteroaromatic ring and the other is an organic compound having a π-electron-deficient heteroaromatic ring skeleton.

[0036] Another embodiment of the present invention is a light-emitting device having the above structure, in which the light-emitting substance emits phosphorescent light.

[0037] Another embodiment of the present invention is a light-emitting device having the above structure, in which the light-emitting substance emits thermally activated delayed fluorescence.

[0038] Another embodiment of the present invention is a light-emitting device having the above structure, in which the light-emitting substance emits light having a wavelength shorter than green light.

[0039] Another embodiment of the present invention is a light-emitting device having the above structure, in which the light-emitting substance emits light whose spectrum peak is located at shorter than or equal to 500 nm.

[0040] Another embodiment of the present invention is a display module comprising the above display device and a terminal and / or an integrated circuit.

[0041] Another embodiment of the present invention is an electronic device comprising the above display module and a housing and / or a battery and / or a camera and / or a speaker and / or a microphone. Effect of the invention

[0042] According to one embodiment of the present invention, a high-reliability light-emitting device formed using an organic compound by a photolithography method can be provided. According to another embodiment of the present invention, a light-emitting device can be provided that can provide a light-emitting device with high image sharpness and high reliability.

[0043] According to another embodiment of the present invention, a highly reliable light-emitting device capable of high density can be provided. According to another embodiment of the present invention, a highly reliable light-emitting device capable of providing a display device with high image sharpness can be provided.

[0044] According to another embodiment of the present invention, a display device with high reliability can be provided. According to another embodiment of the present invention, a display device with high resolution and favorable display performance can be provided. According to another embodiment of the present invention, a display device with favorable display quality and display performance can be provided.

[0045] According to another embodiment of the present invention, a novel display device, a novel display module and a novel electronic device can be provided.

[0046] It should be noted that the description of these effects does not preclude the existence of further effects. An embodiment of the present invention does not necessarily have to exhibit all of these effects. Further effects can be derived from the explanation of the description, the drawings, and the claims. Short description of the drawings Fig. 1A to Fig. 1C are diagrams each illustrating a light-emitting device. Fig. 2 is a diagram illustrating light-emitting devices. Fig. 3A and Fig. 3B are a plan view of a light-emitting device and a cross-sectional view of the light-emitting device, respectively. Fig. 4A to Fig. 4E are cross-sectional views each illustrating an example of a manufacturing method of a display device. Fig. 5A to Fig. 5D are cross-sectional views each showing the example of the manufacturing process of a display device. Fig. 6A to Fig. 6D are cross-sectional views each showing the example of the manufacturing process of a display device. Fig. 7A to Fig. 7C are cross-sectional views each showing the example of the manufacturing process of a display device. Fig. 8A to Fig. 8C are cross-sectional views each showing the example of the manufacturing process of the display device. Fig. 9A to Fig. 9C are cross-sectional views each showing the example of the manufacturing process of the display device. Fig. 10A and Fig. 10B are perspective views each showing a structural example of a display module. Fig. 11A and Fig. 11B are cross-sectional views each showing a structural example of a display device. Fig. 12 is a perspective view showing a structural example of a display device. Fig. 13 is a cross-sectional view showing a structural example of a display device. Fig. 14 is a cross-sectional view showing a structural example of a display device. Fig. 15 is a cross-sectional view showing a structural example of a display device. Fig. 16A to Fig. 16D are diagrams, each showing an example of electronic devices. Fig. 17A to Fig. 17F are diagrams, each showing an example of electronic devices. Fig. 18A to Fig. 18G are illustrations, each showing an example of electronic devices. Fig. 19A is a diagram showing an absorption spectrum of an organic compound used in a light-emitting layer of a light-emitting device 1, and Fig. Figure 19B is a graph showing an emission spectrum of a fluorescent lamp and an emission spectrum of orange light. Fig. 20A is a diagram showing an absorption spectrum of an organic compound used in a light-emitting layer of a light-emitting device 2, and Fig. Figure 20B is a diagram showing the emission spectrum of the fluorescent lamp and the emission spectrum of orange light. Fig. 21A is a diagram showing an absorption spectrum of an organic compound used in a light-emitting layer of a light-emitting device 3, and Fig. Figure 21B is a diagram showing the emission spectrum of the fluorescent lamp and the emission spectrum of orange light. Fig. 22A is a diagram showing an absorption spectrum of an organic compound used in a light-emitting layer of a light-emitting device 4, and Fig. Figure 22B is a diagram showing the emission spectrum of the fluorescent lamp and the emission spectrum of orange light. Fig. 23A to Fig. 23D are diagrams illustrating initial characteristics of the light-emitting device 1. Fig. 24A to Fig. 24D are diagrams illustrating initial characteristics of the light-emitting device 2. Fig. 25A to Fig. 25D are diagrams illustrating initial characteristics of the light-emitting device 3. Fig. 26A to Fig. 26D are diagrams illustrating initial characteristics of the light-emitting device 4. Fig. 27A to Fig. 27D are diagrams each showing a change in luminance over the operating time of the light-emitting devices 1 to 4. Fig. 28A is a diagram illustrating an absorption spectrum of a host material used in a light-emitting layer of a light-emitting device 5, and Fig. Figure 28B is a diagram showing the emission spectrum of the fluorescent lamp and the emission spectrum of orange light. Fig. 29 is a graph showing the luminance-current density characteristics of the light-emitting devices 5. Fig. 30 is a graph illustrating the power efficiency-luminance characteristics of the light-emitting devices 5. Fig. 31 is a diagram illustrating the luminance-voltage characteristics of the light-emitting devices 5. Fig. 32 is a diagram illustrating the current density-voltage characteristics of the light-emitting devices 5. Fig. 33 is a diagram illustrating blue index luminance characteristics of the light-emitting devices 5. Fig. 34 is a diagram showing emission spectra of the light-emitting devices 5. Fig. 35 is a graph illustrating changes in luminance over the operating time of the light-emitting devices 5. Fig. 36A is a diagram showing an absorption spectrum of a host material used in a light-emitting layer of a comparative light-emitting device 1, and Fig. Figure 36B is a diagram showing the emission spectrum of the fluorescent lamp and the emission spectrum of orange light. Fig. 37 is a graph showing the luminance-current density characteristics of the comparative light-emitting devices 1. Fig. 38 is a graph showing the power efficiency-luminance characteristics of the comparative light-emitting devices 1. Fig. 39 is a graph showing the luminance-voltage characteristics of the comparative light-emitting devices 1. Fig. 40 is a graph showing the current density-voltage characteristics of the comparative light-emitting devices 1. Fig. 41 is a graph showing blue index luminance characteristics of the comparative light-emitting devices 1. Fig. 42 is a diagram showing emission spectra of the comparative light-emitting devices 1. Fig. 43 is a graph showing changes in luminance over the operating time of the comparative light-emitting devices 1. Fig. 44A is a diagram showing an absorption spectrum of a host material used in a light-emitting layer of a comparative light-emitting device 2, and Fig. Figure 44B is a diagram showing the emission spectrum of the fluorescent lamp and the emission spectrum of orange light. Fig. 45 is a graph showing the luminance-current density characteristics of the comparative light-emitting devices 2. Fig. 46 is a graph showing the power efficiency-luminance characteristics of the comparative light-emitting devices 2. Fig. 47 is a graph showing the luminance-voltage characteristics of the comparative light-emitting devices 2. Fig. 48 is a graph showing the current density-voltage characteristics of the comparative light-emitting devices 2. Fig. 49 is a graph illustrating external quantum efficiency-luminance characteristics of the comparative light-emitting devices 2. Fig. 50 is a diagram showing emission spectra of the comparative light-emitting devices 2. Fig. 51 is a graph showing changes in luminance over the operating time of the comparative light-emitting devices 2. Fig. 52A and Fig. 52B are diagrams each showing absorption capacities of host materials. Fig. Figure 53 is a diagram showing a molar absorption coefficient of light-emitting substances. Embodiments of the invention

[0047] Embodiments will be described in detail with reference to drawings. It should be noted that the present invention is not limited to the following description, and it will be readily apparent to those skilled in the art that modes and details of the present invention can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as limited to the description of the following embodiments.

[0048] In this specification and the like, a device formed using a metal mask or a fine metal mask (FMM) may be referred to as a device having a metal mask (MM) structure. In this specification and the like, a device formed without using a metal mask or an FMM may be referred to as a device having a metal maskless (MML) structure. (Embodiment 1)

[0049] A vacuum evaporation method using a metal mask (mask evaporation) is widely used as a method for forming an organic semiconductor film into a predetermined shape. However, in recent years, the density and image sharpness have increased; therefore, the enhanced image sharpness in mask deposition is almost at its peak due to problems, typically a problem with the degree of alignment accuracy and a problem with the substrate arrangement interval.

[0050] Meanwhile, it is expected that if the shape of an organic semiconductor film is processed using a photolithography method, an organic semiconductor device with a denser pattern can be achieved. Furthermore, processing an organic semiconductor film using a photolithography method is also being investigated, as the area can be easily increased compared to evaporation using a mask.

[0051] However, processing the shape of the organic semiconductor film through a photolithography process involves many challenges. Examples of these challenges include the influence of air exposure of the organic semiconductor film, the influence of light irradiation during the exposure of a photosensitive resin, and the influence of a developing solution and water to which an exposed photosensitive resin is exposed during its development. As a result of these factors, the characteristics of light-emitting devices produced by a photolithography process are often inferior to those of light-emitting devices formed by a continuous vacuum process.

[0052] One factor contributing to these defects is the generation of impurities (degradation products) due to deterioration of a material contained in the light-emitting device. Such impurities (degradation products) are known to be generated as a result of light irradiation in an air atmosphere.

[0053] The impurities are, for example, a decomposition product or an oxygen adduct of a material and can actually be detected. The generation of such impurities and their presence in the light-emitting device have a significant impact on the initial characteristics and reliability. Therefore, it is difficult to process the light-emitting device containing such impurity-generating material through a photolithography process.

[0054] However, here, the processing of the organic semiconductor film can be performed without deterioration by using light that does not contain short wavelength components shorter than or equal to 475 nm as the light irradiated to the organic semiconductor film in the air atmosphere instead of white light, or by not performing light irradiation. That is, the light-emitting device can be processed through a photolithography process without generating impurities (degradation products) by not performing irradiation with high-energy light containing short wavelength components shorter than or equal to 475 nm in the air exposure step of the photolithography process.

[0055] However, white light is generally used as illumination, and white light often contains short wavelength components of less than or equal to 475 nm. Therefore, by replacing white light-emitting illumination with one that does not contain light with a wavelength of less than or equal to 475 nm, such as orange light-emitting illumination, the light-emitting device can be processed through a photolithography process without generating impurities (degradation products), but this requires a relatively significant capital investment. Furthermore, visibility decreases under illumination where short wavelength components are reduced, and problems could easily be overlooked.

[0056] In one embodiment of the present invention, a material other than a light-emitting substance contained in a light-emitting layer of the light-emitting device (hereinafter referred to as a host material, wherein the host material may be made of a variety of organic substances) is an organic compound in which, among absorption edges in the absorption spectrum of the material, the absorption edge having the longest wavelength is located at shorter than 400 nm, whereby a light-emitting device can be provided whose deterioration is suppressed even when an organic semiconductor film is exposed to air under a white illumination such as a fluorescent lamp or a white LED.In other words, since the host material does not absorb light with a wavelength of 400 nm to 475 nm, an unstable excitation state is not formed; therefore, a light-emitting device can be provided whose deterioration is suppressed even when exposed to air under white illumination, such as a fluorescent lamp or a white LED. Note that a light-emitting substance refers to a substance that actually emits light in the light-emitting layer.

[0057] The expression "does not absorb light having a wavelength of 400 nm to 475 nm" means that, for example, in a 50 nm thick film containing a host material, the absorbance at a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm is less than or equal to 0.05, preferably less than or equal to 0.01, more preferably less than or equal to 0.005, even more preferably less than or equal to 0.001.

[0058] In this case, even if, with respect to the light-emitting substance, the absorption edge with the longest wavelength is located at a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm among the absorption edges in the absorption spectrum of the light-emitting substance, the deterioration of the light-emitting device is not promoted. Therefore, among the absorption edges in the absorption spectrum of the light-emitting substance, the absorption edge with the longest wavelength may be located at a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm.In other words, in the organic semiconductor film containing the light-emitting substance and the host material, even if the light-emitting substance absorbs high-energy light with a wavelength of 400 nm to 475 nm, the light-emitting device whose deterioration is suppressed can be provided as long as the host material does not absorb the high-energy light with a wavelength of 400 nm to 475 nm, even if the air exposure is performed under white illumination such as a fluorescent lamp or a white LED. Note that the wavelength difference between the absorption edge with the longest wavelength in the absorption spectrum of the host material and the absorption edge with the longest wavelength in the absorption spectrum of the light-emitting substance is preferably greater than or equal to 60 nm.Thus, the energy of light absorbed by the light-emitting substance can be suppressed from being transferred to the host material by the influence of the energy of room temperature, an electric field, or the like, whereby the light-emitting device whose deterioration is suppressed can be provided, which is preferable.

[0059] The molar absorption coefficient of the light-emitting substance at a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm may be greater than or equal to 1000 M -1 ·cm -1 , greater than or equal to 2000 M -1 ·cm -1 , greater than or equal to 5000 M -1 ·cm -1 or greater than or equal to 10000 M -1 ·cm -1 be.

[0060] In addition, the light-emitting substance is a phosphorescent light-emitting material, particularly a material that emits phosphorescent light having a wavelength shorter than green light, preferably a material that emits phosphorescent light having a spectrum peak shorter than or equal to 500 nm, whereby the excitation energy of the host material in which the absorption edge with the longest wavelength is located at a wavelength shorter than 400 nm among the absorption edges can be efficiently transferred to the light-emitting substance and light can be emitted, which is preferable.

[0061] Alternatively, the light-emitting substance is a material that exhibits thermally activated delayed fluorescence, which can efficiently transfer the excitation energy of the host material, in which the absorption edge with the longest wavelength is located at a wavelength shorter than 400 nm among the absorption edges, and emit light, which is preferable.

[0062] It should be noted that the absorption spectrum can be measured either in a thin-film state or in a solution state. When comparing the spectra per se, the comparison is preferably performed on the samples in the same state, e.g., a thin-film state or a solution state.

[0063] When measuring in a solution state, hexane, benzene, toluene, diethyl ether, ethyl acetate, chloroform, chlorobenzene, dichloromethane, 2-methyltetrahydrofuran (2-MeTHF), or the like can be used as the solvent; preferably, toluene, dichloromethane, or 2-MeTHF is used. Furthermore, when observing a phosphorescent component at low temperature, a mixed solvent with a ratio of iodobenzene: dichloromethane: toluene = 20%:40%:40% or the like can be used, in which case a favorable glassy state can be formed.

[0064] The wavelength of the absorption edge in the absorption spectrum may be a wavelength at a crossing point of the horizontal axis (wavelength) or the base line and a tangent drawn using a peak located among the absorption edges in the absorption spectrum at the longest wavelength as a reference to a value at which the slope of the spectrum on the longer wavelength side than the peak is most negative.

[0065] In a light-absorbing host material, a fragile framework in the host material is affected and thus deteriorates. In the light-emitting device of one embodiment of the present invention, by having the molecular structure of the host material in the light-emitting layer not contain a condensed aromatic ring composed solely of six-membered rings, a light-emitting device can be provided whose deterioration is suppressed even when air exposure is performed under white illumination, such as a fluorescent lamp or a white LED.In the case where the molecular structure of the host material in the light-emitting layer does not contain a condensed aromatic ring formed only of six-membered rings, the light-emitting device can be provided whose deterioration is suppressed and which has resistance to air exposure under a white illumination such as a fluorescent lamp or a white LED, even if the wavelength of the absorption edge with the longest wavelength is longer than or equal to 400 nm among the absorption edges in the absorption spectrum of the host material.It should be noted that the host material more preferably has a structure in which no condensed aromatic ring formed only of six-membered rings is contained, and among the absorption edges in the absorption spectrum, the wavelength of the absorption edge having the longest wavelength is shorter than or equal to 400 nm.

[0066] Examples of the condensed aromatic ring formed solely from six-membered rings include a structure in which two or more adjacent six-membered aromatic hydrocarbon rings are condensed, a structure in which two or more adjacent six-membered heteroaromatic rings are condensed, and a structure in which one or more six-membered aromatic hydrocarbon rings and one or more adjacent six-membered heteroaromatic rings are condensed. Examples of the six-membered aromatic hydrocarbon ring include a benzene ring. Examples of the six-membered heteroaromatic ring include a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an oxazine ring, a pyran ring, a dioxin ring, a thiopyran ring, a thiazine ring, and a dithiin ring.

[0067] As an example of a structure in which two or more adjacent six-membered aromatic hydrocarbon rings are fused, a naphthalene structure can be cited in which two adjacent six-membered aromatic hydrocarbon rings are fused. As examples of the fused ring having a naphthalene structure, a naphthalene ring, an anthracene ring, a phenanthrene ring, a triphenylene ring, a pyrene ring, a chrysene ring, a tetraphene ring, a perylene ring, and a naphthacene ring can be cited. As an example of a structure in which two or more adjacent six-membered heteroaromatic rings are fused, a naphthydyrine ring, a pteridine ring, and an anthyridine ring can be cited.As an example of a structure in which one or more six-membered aromatic hydrocarbon rings and one or more six-membered heteroaromatic rings adjacent to each other are condensed, there can typically be given a quinoline ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, a phthalazine ring, a cinnoline ring, a phenanthridine ring, an acridine ring, a phenanthroline ring, a phenazine ring, a phenoxazine ring, and a phenothiazine ring.

[0068] In the case where the host material in the light-emitting layer does not have the above-described fragile framework, the light-emitting device can be provided in which deterioration is suppressed even upon exposure to air under white illumination such as a fluorescent lamp or a white LED, even if the wavelength of the absorption edge with the longest wavelength is longer than or equal to 400 nm among the absorption edges in the absorption spectrum of the host material. Note that even in the case where the host material in the light-emitting layer does not have the above-described fragile framework, the wavelength of the absorption edge with the longest wavelength is preferably shorter than 400 nm among the absorption edges in the absorption spectrum of the host material, in which case deterioration is further suppressed.

[0069] Note that in the case where the host material in the light-emitting layer does not have the above-described fragile framework, the case where the host material does not comprise a condensed ring and the case where the host material comprises a condensed ring without the above-described structure are included.

[0070] In other words, in the light-emitting device of one embodiment of the present invention, in the case of the host material having a condensed ring, the condensed ring is a condensed aromatic ring formed of less than or equal to 10 elements, or a condensed ring having a structure in which a five-membered ring and a six-membered ring are alternately condensed.In the case of the host material having a plurality of condensed rings, it is preferable that the plurality of condensed rings do not have a structure in which two or more adjacent six-membered aromatic hydrocarbon rings are condensed; that the plurality of condensed rings are each a condensed aromatic ring formed of less than or equal to 10 elements, or a condensed ring having a structure in which a five-membered ring and a six-membered ring are alternately condensed; and that all of the plurality of condensed rings are condensed aromatic rings formed of less than or equal to 10 elements, or condensed rings having a structure in which a five-membered ring and a six-membered ring are alternately condensed.Specific examples of the condensed ring include an indene ring, a fluorene ring, an indacene ring, a pyrindine ring, an indoline ring, a carbazole ring, a benzofuran ring, a dibenzofuran ring, a benzothiophene ring, a dibenzothiophene ring, an indolocarbazole ring, an indole ring, an isoindole ring, an indazole ring, a purine ring, an azaindole ring, a benzoxazole ring, and a benzothiazole ring. When all of the condensed rings in the host material each have such a structure, the light-emitting device can be provided in which the light emitting device can be emitted even upon exposure to air under a white light such as a fluorescent lamp. B. a fluorescent lamp or a white LED, the deterioration is suppressed even if, among the absorption edges in the absorption spectrum of the host material, the wavelength of the absorption edge with the longest wavelength is longer than or equal to 400 nm.It should be noted that even if all of the condensed rings in the host material each have such a structure, among the absorption edges in the absorption spectrum of the host material, the wavelength of the absorption edge having the longest wavelength is preferably shorter than 400 nm, in which case the deterioration is further suppressed.

[0071] Note that in the case where the host material is formed of a plurality of materials, the plurality of host materials preferably each has the structure described above. That is, for example, in the case where the host material is formed of two types of materials, the second host material, like the host material described above, is preferably an organic compound having the absorption edge with the longest wavelength among absorption edges shorter than 400 nm in the absorption spectrum. Alternatively, the second host material preferably does not absorb high-energy light having a wavelength of 400 nm to 475 nm. Alternatively, the molecular structure of the second host material preferably does not include a condensed aromatic ring formed only of six-membered rings.Alternatively, the second host material preferably has neither a structure in which two or more adjacent six-membered aromatic hydrocarbon rings are condensed, nor a structure in which two or more adjacent six-membered heteroaromatic rings are condensed, nor a structure in which one or more six-membered aromatic hydrocarbon rings and one or more adjacent six-membered heteroaromatic rings are condensed. Alternatively, the second host material preferably does not comprise a condensed ring having a naphthalene structure, such as a naphthalene ring, anthracene ring, phenanthrene ring, or naphthacene ring.Alternatively, the second host material preferably does not have a structure in which two or more adjacent six-membered aromatic hydrocarbon rings are condensed, and preferably comprises a condensed aromatic ring formed of less than or equal to 10 elements, or a condensed ring having a structure in which a five-membered ring and a six-membered ring are alternately condensed.

[0072] In the case where the host material is formed of two types of materials, it is preferable that one of them has an electron-transport property and the other has a hole-transport property. In other words, it is preferable that one of the two types of host materials is an organic compound with an electron-transport property, and the other is an organic compound with a hole-transport property.

[0073] The organic compound with an electron transport property has an electron mobility higher than or equal to 1 × 10 -7 cm 2 / Vs, preferably higher than or equal to 1 × 10 -6 cm 2 / Vs, where the square root of the electric field strength [V / cm] is 600. It should be noted that other substances can also be used as long as the substances have higher electron transport properties than hole transport properties. In addition, an organic compound having a π-electron-deficient heteroaromatic ring skeleton is preferred. As the organic compound having a π-electron-deficient heteroaromatic ring skeleton, for example, an organic compound having a heteroaromatic ring with a polyazole skeleton, an organic compound having a heteroaromatic ring with a pyridine skeleton, an organic compound having a heteroaromatic ring with a diazine skeleton, and an organic compound having a heteroaromatic ring with a triazine skeleton can be given. In particular, the organic compound having a heteroaromatic ring with a diazine skeleton (a pyrimidine skeleton,a pyrazine skeleton and a pyridazine skeleton), the organic compound having a heteroaromatic ring with a pyridine skeleton, and the organic compound having a heteroaromatic ring with a triazine skeleton have high reliability and are thus preferred. In particular, the organic compound having a heteroaromatic ring with a diazine (pyrimidine or pyrazine) skeleton and the organic compound having a heteroaromatic ring with a triazine skeleton each have a high electron transport property and contribute to a reduction in operating voltage. Alternatively, a benzofuropyrimidine skeleton, a benzothienopyrimidine skeleton, a benzofuropyrazine skeleton, and a benzothienopyrazine skeleton are preferred due to their high acceptor properties and high reliability. Examples of such an organic compound include an organic compound having an azole skeleton,such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 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) or 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), an organic compound containing a heteroaromatic ring with a pyridine skeleton, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP) or 2,9-Di(naphthalen-2-yl)-4,7-diphenyl-1, 10-phenanthroline (abbreviation: NBPhen), 2,2'-(1,3-Phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: mTpPPhen), 2-phenyl-9-(2-triphenylenyl)-1,10-phenanthroline (abbreviation: Ph-TpPhen), 2-[4-(9-phenanthrenyl)-1-naphthalenyl]-1,10-phenanthroline (abbreviation: PnNPhen) or 2-[4-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen), an organic compound with a diazine skeleton, such as. B. 2-[3-(Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3-3'-(Dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-Diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II),and 6-[3-(Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-{3-[3-(N-Phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), 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: 9mDBtBPNfpr), 4,6-Bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-Bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-Bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[Pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(Biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(Dibenzothiophen-4-yl)(biphenyl-3-yl)]naphtho[1',2':4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-Binaphthalene)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(Pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(Pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(Biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-Bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-Bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm) and 7-[4-(9-Phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PCcgDBCzQz), an organic compound containing a heteroaromatic ring with a triazine skeleton, such as 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[h]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 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), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (Abbreviation: mFBPTzn), 5-[3-(4,6-Diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (Abbreviation: mlNc(II)PTzn), 2-{3-[3-(Dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-Tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-Dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-trizazine (abbreviation: mPn-mDMePyPTzn),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), 2-[3'-(Triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(Biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4', 1"-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-[4-(2-naphthalenyl)phenyl]-4-phenyl-6-spiro[9H-fluoren-9,9'-[9H]xanthen]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)Tzn); and among the organic compounds, an organic compound which does not comprise a condensed aromatic ring formed only of six-membered rings, or an organic compound having neither a structure in which two or more adjacent six-membered aromatic hydrocarbon rings are condensed, nor a structure in which two or more adjacentSix-membered heteroaromatic rings are condensed, nor is a structure in which one or more six-membered aromatic hydrocarbon rings and one or more six-membered heteroaromatic rings adjacent to each other are condensed. Among these, the organic compound having a heteroaromatic ring with a diazine skeleton, the organic compound having a heteroaromatic ring with a pyridine skeleton, and the organic compound having a heteroaromatic ring with a triazine skeleton each have high reliability and are thus preferred. In particular, the organic compound having a heteroaromatic ring with a diazine (pyrimidine or pyrazine) skeleton and the organic compound having a heteroaromatic ring with a triazine skeleton each have a high electron-transport property, contribute to a reduction in operating voltage, and are thus preferred.

[0074] The organic compound with a hole transport property has a hole mobility higher than or equal to 1 × 10 -7 cm 2 / Vs, preferably higher than or equal to 1 × 10 -6 cm 2 / Vs, where the square root of the electric field strength [V / cm] is 600. It should be noted that other substances can also be used as long as the substances have higher hole-transport properties than electron-transport properties. Furthermore, an organic compound having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton is preferred. Examples of such an organic compound include a compound having an aromatic amine skeleton, such as4,4'-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-Diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-Bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-Phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-Phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-Phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-Diphenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-Naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-Di(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-Dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF) and N-Phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF), a compound with a carbazole skeleton, such as e.g.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) and 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), a compound with a thiophene skeleton, such as. B. 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) and an organic compound with a furan skeleton, such as4,4',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); and among the organic compounds, an organic compound not comprising a condensed aromatic ring formed only of six-membered rings, or an organic compound having neither a structure in which two or more adjacent six-membered aromatic hydrocarbon rings are condensed, nor a structure in which two or more adjacent six-membered heteroaromatic rings are condensed, nor a structure in which one or more six-membered aromatic hydrocarbon rings and one or more six-membered heteroaromatic rings adjacent to each other are condensed is preferred.Among the above compounds, the compound having an aromatic amine skeleton or the compound having a carbazole skeleton is preferred because these compounds have high reliability and high hole transport property and contribute to a reduction in operating voltage.

[0075] The light-emitting device of one embodiment of the present invention having the above structure can be the light-emitting device with advantageous characteristics, whose deterioration is suppressed even during manufacturing by a photolithography process. In particular, the light-emitting device can have high reliability. Alternatively, the light-emitting device can have a low operating voltage. Alternatively, the light-emitting device can have high emission efficiency. (Embodiment 2)

[0076] In this embodiment, the light-emitting device of one embodiment of the present invention will be described in detail.

[0077] Fig. 1 is a schematic diagram of the light-emitting device of one embodiment of the present invention. In a light-emitting device 130, a first electrode 101 is provided over an insulator, and an organic compound layer 103 is sandwiched between the first electrode 101 and a second electrode 102. The organic compound layer 103 includes at least one light-emitting layer 113, and the light-emitting layer 113 includes a light-emitting substance and a host material. The light-emitting substance emits light by applying a voltage between the first electrode 101 and the second electrode 102.There are both the case where the organic compound layer 103 is formed of only a first layer 104 unique to the light-emitting device and the case where the organic compound layer 103 has a multi-layer structure of the first layer 104 unique to the light-emitting device and a second layer (a common layer) 105 shared by a plurality of light-emitting devices.

[0078] The host material corresponds to the host material described in Embodiment 1. Note that, as described in Embodiment 1, the host material can be formed from a variety of materials. For example, in the case where the host material is formed from two types of materials, the light-emitting layer 113 contains a light-emitting substance, a first substance, and a second substance; and in the case where the host material is formed from three types of materials, the light-emitting layer contains a light-emitting substance, a first substance, a second substance, and a third substance. In the case where the host material is formed from a variety of materials, all of the variety of materials are preferably substances having the feature of the host material in Embodiment 1.The details of the structure of the host material and the substance to be used are described in Embodiment 1, and therefore the repeated description is omitted.

[0079] The organic compound layer 103 preferably comprises, in addition to the light-emitting layer 113, functional layers such as a hole injection layer 111, a hole transport layer 112, an electron transport layer 114 and an electron injection layer 115, as shown in Fig. 1A. Note that the organic compound layer 103 may include functional layers other than the above functional layers, such as a hole-blocking layer, an electron-blocking layer, an exciton-blocking layer, and a charge-generation layer. Alternatively, any of the above layers may be omitted.

[0080] Although in this embodiment, the first electrode 101 comprises an anode and the second electrode 102 comprises a cathode, the reverse is possible. The first electrode 101 and the second electrode 102 each have a single-layer structure or a multi-layer structure, and in the case of the multi-layer structure, a layer in contact with the organic compound layer 103 serves as the anode or cathode. In the case where the electrodes each have the multi-layer structure, there is no limitation on the work functions of materials for layers other than the layer in contact with the organic compound layer 103, and the materials can be selected according to required properties such as resistance, ease of processing, reflectivity, light transmittance, and stability.

[0081] The anode is preferably formed using a metal, an alloy, a conductive compound with a high work function (particularly, a work function greater than or equal to 4.0 eV), a mixture thereof, or the like. Specifically, indium oxide-tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide (ITSO), indium oxide-zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO) are given, for example. These conductive metal oxide films are usually formed by a sputtering method, but they can also be formed by using a sol-gel method or the like. In one example of the formation method, indium oxide-zinc oxide is formed by a sputtering method using a target obtained by adding 1 wt% to 20 wt% of zinc oxide to indium oxide.Furthermore, indium oxide containing tungsten oxide and zinc oxide (IWZO) can be formed by a sputtering method using a target in which 0.5 wt% to 5 wt% of tungsten oxide and 0.1 wt% to 1 wt% of zinc oxide are added to indium oxide. Other materials used for the anode include gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), aluminum (Al), a nitride of a metal material (e.g., titanium nitride), and the like. The anode can be a layered arrangement of any of these materials. For example, a film in which Al, Ti, and ITSO are stacked in this order over Ti is preferred because the film has high efficiency due to high reflectivity and enables high image sharpness of several thousand ppi. Alternatively, graphene can be used for the anode material.When a composite material, which may be included in the hole injection layer 111 described later, is used for a layer (typically the hole injection layer) in contact with the anode, an electrode material can be selected regardless of its work function.

[0082] The hole injection layer 111 is provided in contact with the anode and has a function of facilitating the injection of holes into the organic compound layer 103. Alternatively, the hole injection layer 111 may be formed using a phthalocyanine-based compound or a phthalocyanine-based complex compound such as phthalocyanine (abbreviation: H2Pc) and copper phthalocyanine (abbreviation: CuPc), an aromatic amine compound such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB) and 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), or a high molecular compound such as phthalocyanine (abbreviation: DPAB). B. Poly(3,4-ethylenedioxythiophene) / (polystyrenesulfonic acid) (abbreviation: PEDOT / PSS).

[0083] The hole injection layer 111 can be formed using a substance having an electron acceptor property. As a substance with an acceptor property, an organic compound with an electron-withdrawing group (e.g. a halogen group or a cyano group) can be used, for example, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ) or 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile can be specified. A compound in which an electron-withdrawing group is bonded to a condensed aromatic ring containing multiple heteroatoms, such as HAT-CN, is particularly preferred because it is thermally stable. A [3]radialene derivative containing an electron-withdrawing group (especially a cyano group, a halogen group, such asa fluorine group, and the like) has a very high electron accepting property and is thus preferred; and specific examples include α,α',α''-1,2,3-cyclopropanetriylidene tris[4-cyano-2,3,5,6-tetrafluorobenzene acetonitrile], α,α',α''-1,2,3-cyclopropanetriylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzene acetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidene tris[2,3,4,5,6-pentafluorobenzene acetonitrile]. As the substance having an accepting property, in addition to the above-described organic compounds, a transition metal oxide such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can be used.

[0084] The hole injection layer 111 is preferably formed using a composite material containing any of the above-mentioned materials having an acceptor property and an organic compound having a hole transport property.

[0085] As the organic compound having a hole-transport property used for the composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, and high-molecular compounds (e.g., oligomers, dendrimers, or polymers) can be used. It should be noted that the organic compound having a hole-transport property used for the composite material is preferably an organic compound with a hole mobility of greater than or equal to 1 × 10 -6 cm 2 / Vs. The organic compound having a hole-transport property used for the composite material is preferably a compound having a condensed aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the condensed aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, or the like is preferred. As the π-electron-rich heteroaromatic ring, a condensed aromatic ring having at least one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton in the ring is preferred; in particular, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is further condensed with a carbazole ring or a dibenzothiophene ring is preferred.

[0086] Such an organic compound having a hole-transport property more preferably has a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton. Specifically, an aromatic amine having a substituent comprising a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group can be used. Note that these organic compounds having a hole-transport property preferably have an N,N-bis(4-biphenyl)amino group because a light-emitting device with a long lifetime can be fabricated.

[0087] Specific examples of the above organic compounds having a hole-transport property include 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: TPBiAßNB), 4-(3-Biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4"-phenyltriphenylamine (abbreviation: mTPBiAßNBi), 4-(4-Biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4"-phenyltriphenylamine (abbreviation: TPBiAßNBi), 4-Phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-Bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-Diphenyl-4"-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP),4'-[4-(3-Phenyl-9H-carbazol-9-yl)phenyl]tris(biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(Carbazol-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4"-phenyltriphenylamine (abbreviation: YGTBißNB), 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-fluoren]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluoren]-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'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-Phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-Phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi),4-Phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-Phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 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 and N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine.

[0088] As other aromatic amine compounds, which are materials with high hole transport properties, N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4'-bis(N-{4-[N-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD) and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B) can be used.

[0089] The formation of the hole injection layer 111 can improve the hole injection property, resulting in the light-emitting device with low operating voltage can be obtained.

[0090] Among substances with an acceptor property, the organic compound with an acceptor property is easy to use because it is easily deposited by evaporation.

[0091] The hole-transport layer 112 is formed using an organic compound having a hole-transport property. The organic compound having a hole-transport property preferably has a hole mobility of greater than or equal to 1 × 10 -6 cm 2 / Vs. The organic compound having a hole-transport property is preferably an organic compound having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton. As the π-electron-rich heteroaromatic ring, a condensed aromatic ring having at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton is preferred; in particular, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is further condensed with a carbazole ring or a dibenzothiophene ring is preferred.

[0092] Such an organic compound having a hole-transport property more preferably has a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton. Specifically, an aromatic amine having a substituent comprising a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group can be used. Note that the organic compound having a hole-transport property preferably has an N,N-bis(4-biphenyl)amino group because a light-emitting device with a long lifetime can be produced.

[0093] Examples of the above organic compound having a hole-transporting property include a compound having an aromatic amine skeleton, such as: B. 4,4'-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-Diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-Bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-Phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-Phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-Phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-Diphenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-Di(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-Dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF) and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF); a compound with a carbazole skeleton, such as B. 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), 9-(2-Naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP), 9-(3-Biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-Biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-Di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisßNCz), 9-(2-Naphthyl)-9'-[1,1'-4',1''-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1''-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-Naphthyl)-9'-[1,1':3',1''-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1'-4',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-Naphthyl)-9'-[1,1'-3',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-Naphthyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-bis(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole and 9-(triphenylen-2-yl)-9'-[1,1':3',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole; a compound having a thiophene skeleton, such as B. 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); and a compound with a furan skeleton, such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl} dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above compounds, the compound having an aromatic amine skeleton and the compound having a carbazole skeleton are preferred because these compounds are highly reliable, exhibit high hole-transport properties, and contribute to a reduction in operating voltage. Note that any of the substances given as examples of the material having a hole-transport property used for the composite material for the hole-injection layer 111 can also be suitably used as the material contained in the hole-transport layer 112.

[0094] Although the emission center substance may be a fluorescent substance, a phosphorescent substance, a thermally activated fluorescence (TADF) material, or another light-emitting substance, a phosphorescent substance or a TADF material is preferred because it can efficiently transfer excitation energy from a host material having an absorption edge with the longest wavelength at a wavelength shorter than or equal to 400 nm among absorption edges. In particular, a material that emits light with a wavelength shorter than green light is preferred, preferably a phosphorescent substance or a TADF material that has a spectrum peak at a wavelength shorter than or equal to 500 nm.

[0095] Examples of materials that can be used as fluorescent substances in the light-emitting layer are as follows. Other fluorescent substances can also be used.

[0096] 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-Bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-Diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), Perylene, 2,5,8,11-Tetra-tert-butylperylene (abbreviation: TBP), 4-(10-Phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviation: DPABPA), N,9-Diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-Diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-Octaphenyldibenzo[g,p]chrysen-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-Diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), 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)propanedinitrile (abbreviation: DCM1), 2-{2-Methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ / ]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-Tetrakis(4-methylphenyl)tetracen-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-mPhAFD), 2-{2-Isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ / / ]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[ / / ]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-Bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ / / ]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-Diphenyl-N,N'-(1,6-pyrenediyl)bis[(6-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-h;6,7-h']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02). Condensed aromatic diamine compounds, typically pyrenediamine compounds, such as B. 1,6FLPAPrn, 1,6mMemFLPAPrn and 1,6BnfAPrn-03, are particularly preferred due to their high hole-trapping properties, high emission efficiency or high reliability.

[0097] In case of using a phosphorescent substance as a light-emitting substance in the light-emitting layer, examples of the phosphorescent substance are as follows.

[0098] An organometallic iridium complex with a 4H-triazole skeleton, such as 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]) and tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]), an organometallic iridium complex with a 1H-triazole skeleton, such as B. Tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]) and tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), an organometallic iridium complex with an imidazole framework, such as. B. fac-Tris[1-(2,6-diisopropylphenyl)-2-phenyl-1 H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim)3]), Tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]) and Tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazol-2-yl-κN 3}-4-cyanophenyl-κC)iridium(III) (abbreviation: CNImIr), an organometallic complex with a benzimidazolidene framework, such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC 2 )phenyl-κC]iridium(III) (abbreviation: [Ir(cb)3]) and an organometallic iridium complex in which a phenylpyridine derivative with an electron-withdrawing group is a ligand, such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2' ]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2' ]iridium(III)picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2'}iridium(III)picolinate (abbreviation: [Ir(CF3ppy)2(pic)]) and bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2' ]iridium(III) acetylacetonate (abbreviation: FIracac). These compounds exhibit blue phosphorescence and have an emission peak in the wavelength range of 450 nm to 520 nm.

[0099] It is also used in addition to an organometallic iridium complex with a pyrimidine framework, such as: B. Tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (Acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (Acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (Acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (Acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]) and (Acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]); an organometallic iridium complex with a pyrazine framework, 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)]); an organometallic iridium complex with a pyridine framework, such as 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)]); [2-d3-Methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN 2)phenyl-κC]iridium(III) (Abkürzung: [Ir(5mppy-d3)2(mbfpypy-d3)]), {2-(Methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofuro[2,3-b]pyridin-7-yl-κC}bis}5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridinyl-κN]phenyl-rC}iridium(III) (Abkürzung: Ir(5mtpy-d6)2(mbfpypy-iPr-d4)), [2-d3-Methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridin-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (Abkürzung: [Ir(ppy)2(mbfpypy-d3)]), [2-(4-Methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (Abkürzung: [Ir(ppy)2(mdppy)]), [2-(4-d3-Methyl-5-phenyl-2-pyridinyl-κN 2 )phenyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN 2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mdppy-d3)]), [2-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy)]) and [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mdppy)]); a rare earth metal complex, such as For example, tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]) is given. These compounds exhibit predominantly green phosphorescence and exhibit an emission peak in a wavelength range of 500 nm to 600 nm. It should be noted that organometallic iridium complexes with a pyrimidine framework exhibit significantly high reliability or significantly high emission efficiency and are therefore particularly preferred.

[0100] A platinum complex such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum(II) (abbreviation: PtOEP) and a rare earth metal complex 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)])) are used, in addition to an organometallic iridium complex having a pyrimidine framework such as pyrophosphate. B. (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 bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]); an organometallic iridium complex with a pyrazine framework, such as(Acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]) and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]); and an organometallic iridium complex with a pyridine framework, such as 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)]), (3,7-diethyl-4,6-nonandionato-κO 4 ,κO 6 )bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III) and (3,7-diethyl-4,6-nonanedionato- κ O 4 ,κO 6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III). These compounds exhibit red phosphorescence and exhibit an emission peak in the wavelength range of 600 nm to 700 nm. An organometallic iridium complex with a pyrazine framework can provide red light emission with favorable chromaticity.

[0101] In addition to the phosphorescent compounds described above, known phosphorescent compounds can also be selected and used.

[0102] A fullerene, a derivative thereof, an acridine, a derivative thereof, an eosin derivative, and the like can be used as the TADF material. A metal-containing porphyrin, such as a porphyrin containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd), is also mentioned. Examples of the metal-containing porphyrin include a protoporphyrin-tin fluoride complex (SnF2(Proto IX)), a mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), a hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), a coproporphyrin-tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), an octaethylporphyrin-tin fluoride complex (SnF2(OEP)), an etioporphyrin-tin fluoride complex (SnF2(Etio I)) and an octaethylporphyrin-platinum chloride complex (PtCl2OEP), which are represented by the following structural formulas.

[0103] A heterocyclic compound having a π-electron-rich heteroaromatic ring and / or a π-electron-poor heteroaromatic ring and represented by one of the following structural formulas, such as: B. 2-(Biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn) (Abbreviation: PXZ-TRZ), 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) and 10-Phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviation: ACRSA) can also be used.Such a heterocyclic compound is preferred because it exhibits high electron-transport and hole-transport properties due to a π-electron-rich heteroaromatic ring and a π-electron-poor heteroaromatic ring. Among frameworks containing the π-electron-poor heteroaromatic ring, a pyridine framework, a diazine framework (a pyrimidine framework, a pyrazine framework, and a pyridazine framework), and a triazine framework are preferred due to their high stability and high reliability. In particular, a benzofuropyrimidine framework, a benzothienopyrimidine framework, a benzofuropyrazine framework, and a benzothienopyrazine framework are preferred due to their high acceptor properties and high reliability.Among the π-electron-rich heteroaromatic ring skeletons, an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton each exhibit high stability and high reliability; therefore, at least one of these skeletons is preferably included. As the furan skeleton, a dibenzofuran skeleton is preferred, and as the thiophene skeleton, a dibenzothiophene skeleton is preferred. As the pyrrole skeleton, indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a bicarbazole skeleton, and a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton are particularly preferred.It should be noted that a substance in which the π-electron-rich heteroaromatic ring is directly bonded to the π-electron-poor heteroaromatic ring is particularly preferred because both the electron-donating property of the π-electron-rich heteroaromatic ring and the electron-accepting property of the π-electron-poor heteroaromatic ring are improved, the energy difference between the S. 1-level and the T1 level becomes small, and thus thermally activated delayed fluorescence can be obtained with high efficiency. Note that an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded can be used instead of the π-electron-deficient heteroaromatic ring. As the π-electron-rich framework, an aromatic amine framework, a phenazine framework, or the like can be used. As the π-electron-deficient framework, a xanthene framework, a thioxanthene dioxide framework, an oxadiazole framework, a triazole framework, an imidazole framework, an anthraquinone framework, a boron-containing framework such as phenylborane and boranthrene, an aromatic ring, or a heteroaromatic ring having a nitrile group or a cyano group such as phenylborane. B. benzonitrile or cyanobenzene, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton or the like.As described above, a π-electron-poor framework and a π-electron-rich framework can be used instead of the π-electron-poor heteroaromatic ring and / or the π-electron-rich heteroaromatic ring.

[0104] It should be noted that a TADF material is a material that has a small difference between the S 1 level and the T1 level and has the function of converting triplet excitation energy into singlet excitation energy through reverse intersystem crossing. Thus, a TADF material can upconvert triplet excitation energy to singlet excitation energy (i.e., reverse intersystem crossing) using a small amount of thermal energy and efficiently generate a singlet excited state. Furthermore, the triplet excitation energy can be converted into luminescence.

[0105] An exciplex whose excited state is formed by two types of substances has a very small difference between the S 1 level and the T1 level and serves as a TADF material that can convert the triplet excitation energy into the singlet excitation energy.

[0106] A phosphorescence spectrum observed at low temperature (e.g., 77 K to 10 K) is used for an index of the T1 level. If the level of energy with a wavelength of the line obtained by extrapolating a tangent to the fluorescence spectrum at a tail on the short wavelength side, the S 1level and the level of energy having a wavelength of the line obtained by extrapolating a tangent to the phosphorescence spectrum at a tail on the short wavelength side is the T1 level, the difference between the S1 and the T1 of the TADF material is preferably less than or equal to 0.3 eV, more preferably less than or equal to 0.2 eV.

[0107] When a TADF material is used as a light-emitting substance, the S 1 The T1 level of the host material is preferably higher than that of the TADF material. Furthermore, the T1 level of the host material is preferably higher than that of the TADF material.

[0108] As the host material of the light-emitting layer, the material having an electron transport property described in Embodiment 1 and / or the material having a hole transport property described in Embodiment 1 can be used. In addition, among the TADF materials or the like described above, a material that satisfies the conditions described in Embodiment 1 can be used. Furthermore, various charge transport materials can be used as long as they satisfy the conditions described in Embodiment 1.

[0109] The materials mentioned above can also be used as TADF materials for use as host materials. When the TADF material is used as a host material, the triplet excitation energy generated in the TADF material is converted into singlet excitation energy through reverse intersystem crossing and transferred to the light-emitting substance, thereby increasing the emission efficiency of the light-emitting device. Here, the TADF material serves as the energy donor, and the light-emitting substance serves as the energy acceptor.

[0110] This is very effective in the case where the above light-emitting substance is a fluorescent substance. In this case, the S 1 -level of the TADF material is preferably higher than that of the fluorescent substance to achieve high emission efficiency. Furthermore, the T1 level of the TADF material is preferably higher than the S1 -Level of the fluorescent substance. Therefore, the T1 level of the TADF material is preferably higher than that of the fluorescent substance.

[0111] A TADF material that emits light whose wavelength overlaps with the wavelength of an absorption band on the lowest energy side of the fluorescent substance is preferably used. This allows the excitation energy to be smoothly transferred from the TADF material to the fluorescent substance, and thus, light emission can be efficiently obtained, which is preferable.

[0112] Furthermore, charge carrier recombination preferably occurs in the TADF material so that the singlet excitation energy is efficiently generated from the triplet excitation energy through reverse intersystem crossing. It is also preferred that the triplet excitation energy generated in the TADF material is not transferred to the triplet excitation energy of the fluorescent substance. For this reason, the fluorescent substance preferably has a protecting group around a luminophore (a scaffold that generates light emission) of the fluorescent substance.As the protecting group, a substituent without a π bond and a saturated hydrocarbon are preferably used. In particular, an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a trialkylsilyl group having 3 to 10 carbon atoms are mentioned. It is preferable that the fluorescent substance have multiple protecting groups. Substituents without a π bond have poor charge carrier transport performance; therefore, the TADF material and the luminophore of the fluorescent substance can be removed from each other with little effect on charge carrier transport or charge carrier recombination. The luminophore here refers to an atomic group (skeleton) that induces light emission in a fluorescent substance.The luminophore is preferably a backbone having a π bond, more preferably it comprises an aromatic ring, and even more preferably it has a fused aromatic ring or a fused heteroaromatic ring.

[0113] Note that the host material may be a mixture of several types of substances; in the case of using a mixed host material, a material with an electron-transport property and a material with a hole-transport property are preferably mixed. By mixing the material with an electron-transport property and the material with a hole-transport property, the transport property of the light-emitting layer 113 can be easily adjusted, and a recombination range can be easily controlled. The weight ratio of the content of the material with a hole-transport property to the content of the material with an electron-transport property can be 1:19 to 19:1.

[0114] It should be noted that a phosphorescent substance can be used as part of the mixed material. When a fluorescent substance is used as the light-emitting substance, a phosphorescent substance can be used as an energy donor to supply excitation energy to the fluorescent substance.

[0115] An exciplex can be formed from these mixed materials. These mixed materials are preferably selected to form an exciplex that emits light whose wavelength overlaps with the wavelength of an absorption band on the lowest energy side of the light-emitting substance. In this case, energy can be transferred smoothly and light emission can be achieved efficiently. The use of such a structure is preferred because the operating voltage can also be reduced.

[0116] It should be noted that at least one of the materials forming an exciplex can be a phosphorescent substance. This allows the triplet excitation energy to be efficiently converted into the singlet excitation energy through reverse intersystem crossing.

[0117] A combination of a material with electron-transport properties and a material with hole-transport properties, whose HOMO level is higher than or equal to that of the material with electron-transport properties, is preferred for efficient exciplex formation. Furthermore, the LUMO level of the material with hole-transport properties is preferably higher than or equal to that of the material with electron-transport properties. Note that the LUMO levels and HOMO levels of the materials can be determined from the electrochemical properties (reduction potentials and oxidation potentials) of the materials measured by cyclic voltammetry (CV).

[0118] The formation of an exciplex can be confirmed, for example, by a phenomenon in which the emission spectrum of a mixed film in which the material with a hole-transport property and the material with an electron-transport property are mixed is shifted to the longer wavelength side than the emission spectrum of each of the materials (or the emission spectrum has a different peak on the longer wavelength side), which phenomenon is observed by comparing the emission spectrum of the material with a hole-transport property, the emission spectrum of the material with an electron-transport property, and the emission spectrum of the mixed film of these materials. Alternatively, the formation of an exciplex can be confirmed by a difference in the transient response, such asA phenomenon in which the transient PL lifetime of the blend film has more long-lived components or a larger proportion of delayed components than that of either material can be confirmed, with the difference observed by comparing the transient photoluminescence (PL) of the material with a hole-transport property, the transient PL of the material with an electron-transport property, and the transient PL of the blend film of the materials. The transient PL can be reformulated as transient electroluminescence (EL). That is, the formation of an exciplex can also be confirmed by a difference in the transient response observed by comparing the transient EL of the material with a hole-transport property, the transient EL of the material with an electron-transport property, and the transient EL of the blend film of the materials.

[0119] The electron-transport layer 114 contains a substance having an electron-transport property. The organic compound having an electron-transport property has an electron mobility of greater than or equal to 1 × 10 -7 cm 2 / Vs, preferably higher than or equal to 1 × 10 -6 cm 2 / Vs, where the square root of the electric field strength [V / cm] is 600. Note that any other substance can be used as long as the substance has an electron-transport property higher than a hole-transport property. Furthermore, an organic compound having a π-electron-deficient heteroaromatic ring skeleton is preferred. Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include an organic compound having a polyazole skeleton, an organic compound having a heteroaromatic ring with a pyridine skeleton, an organic compound having a heteroaromatic ring with a diazine skeleton, and an organic compound having a heteroaromatic ring with a triazine skeleton.Among the above organic compounds, the organic compound having a heteroaromatic ring with a diazine skeleton (a pyrimidine skeleton, a pyrazine skeleton, and a pyridazine skeleton), the organic compound having a heteroaromatic ring with a pyridine skeleton, and the organic compound having a heteroaromatic ring with a triazine skeleton exhibit high reliability and are thus preferred. In particular, the organic compound having a heteroaromatic ring with a diazine skeleton (a pyrimidine skeleton and a pyrazine skeleton) and the organic compound having a heteroaromatic ring with a triazine skeleton exhibit high electron transport properties and contribute to a reduction in operating voltage.Alternatively, a benzofuropyrimidine scaffold, a benzothienopyrimidine scaffold, a benzofuropyrazine scaffold, and a benzothienopyrazine scaffold are preferred due to their high acceptor properties and high reliability.

[0120] Examples of such organic compounds include an organic compound having an azole skeleton, such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 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) or 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), an organic compound containing a heteroaromatic ring with a pyridine skeleton, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: mTpPPhen), 2-phenyl-9-(2-triphenylenyl)-1,10-phenanthroline (abbreviation: Ph-TpPhen), 2-[4-(9-phenanthrenyl)-1-naphthalenyl]-1,10-phenanthroline (abbreviation: PnNPhen) or 2-[4-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen), an organic compound with a diazine skeleton, such as. B. 2-[3-(Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3-(3'-(Dibenzothiophen-4-yl)biphenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3, 1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-Diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3'-(Dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[(3'-(Dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-Bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-Bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-Bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[Pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(Biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-Bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (Abbreviation: 3,8mDBtP2Bfpr), 4,8-Bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (Abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(Dibenzothiophen-4-yl)(biphenyl-3-yl)]naphtho[1',2':4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthalene)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(Biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm) and 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PCcgDBCzQz), and an organic compound having a heteroaromatic ring with a Triazine skeleton, such as 2-[(biphenyl)-4-yl]-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazin (Abkürzung: mBnfBPTzn), 2-{3-[3-(Benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazin (Abkürzung: mBnfBPTzn-02), 2-{4-[3-(N-Phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazin (Abkürzung: PCCzPTzn), 9-[3-(4,6-Diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazol (Abkürzung: mPCCzPTzn-02), 2-[3'-(9,9-Dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazin (Abkürzung: mFBPTzn), 5-[3-(4,6-Diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazol (Abkürzung: mINc(II)PTzn), 2-{3-[3-(Dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazin (Abkürzung: mDBtBPTzn), 2,4,6-Tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazin (Abkürzung: TmPPPyTz), 2-[3-(2,6-Dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazin (Abkürzung: mPn-mDMePyPTzn), 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), 2-[3'-(triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn) and 2-(biphenyl-3-yl)-4-phenyl-6-[8-(1,1':4',1''-terphenyl)-4-yl-1-dibenzofuranyl]-1,3,5-triazine (abbreviation: mBP-TPDBfTzn); and among the organic compounds, an organic compound which does not comprise a condensed aromatic ring formed only of six-membered rings, or an organic compound having neither a structure in which two or more adjacent six-membered aromatic hydrocarbon rings are condensed, nor a structure in which two or more adjacent six-membered heteroaromatic rings are condensed, nor a structure in which one or more six-membered aromatic hydrocarbon rings and one or more six-membered heteroaromatic rings,which are adjacent to each other, are condensed.,

[0121] Among the above compounds, the organic compound having a heteroaromatic ring with a diazine skeleton, the organic compound having a heteroaromatic ring with a pyridine skeleton, and the organic compound having a heteroaromatic ring with a triazine skeleton have high reliability and are thus preferred. In particular, the organic compound having a heteroaromatic ring with a diazine (pyrimidine or pyrazine) skeleton and the organic compound having a heteroaromatic ring with a triazine skeleton have a high electron-transport property, contribute to a reduction in operating voltage, and are thus preferred. In particular, an organic compound having a phenanthroline skeleton, such as mTpPPhen, PnNPhen, or mPPhen2P, is preferred, and an organic compound having a phenanthroline dimer structure, such as mPPhen2P, is more preferred due to its high stability.

[0122] Note that the electron-transport layer 114 may have a multilayer structure. A layer in contact with the light-emitting layer 113 in the multilayer structure of the electron-transport layer 114 may serve as a hole-blocking layer. In the case where the electron-transport layer in contact with the light-emitting layer serves as a hole-blocking layer, it is preferable to use a material having a HOMO level greater than or equal to 0.5 eV lower than a material contained in the light-emitting layer 113.

[0123] As the electron-injection layer 115, a layer containing a compound or complex of an alkali metal or an alkaline earth metal, such as lithium fluoride, 8-hydroxyquinolinato lithium (abbreviation: Liq), a mixed material of lithium fluoride and ytterbium, and a mixture thereof, 1,1'-pyridine-2,6-diylbis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) (abbreviation: hpp2Py), or the like, may be provided. As the electron-injection layer 115, a layer containing a substance having an electron-transport property and any of the above substances may be used.

[0124] Instead of the electron injection layer 115, a charge generation layer 116 may be provided ( Fig. 1B). The charge generation layer 116 denotes a layer capable of injecting holes into a layer in contact with the cathode side of the charge generation layer and electrons into a layer in contact with its anode side by applying a potential. The charge generation layer 116 includes at least one p-type layer 117. The p-type layer 117 is preferably formed using one of the composite materials cited above as examples of materials that can be used for the hole injection layer 111. The p-type layer 117 can be formed by stacking a film containing the above-described acceptor material as a material contained in the composite material and a film containing a hole-transport material.When a potential is applied to the p-type layer 117, electrons are injected into the electron-transport layer 114 and holes are injected into the cathode, thereby operating an organic EL element. Since the organic compound of one embodiment of the present invention has a low refractive index, when the organic compound is used for the p-type layer 117, the organic EL element can exhibit a high external quantum efficiency.

[0125] It should be noted that the charge generation layer 116 preferably comprises, in addition to the p-type layer 117, an electron relay layer 118 and / or an electron injection buffer layer 119.

[0126] The electron relay layer 118 contains at least one substance with an electron-transport property and has a function of preventing interaction between the electron injection buffer layer 119 and the p-type layer 117 and a function of smoothly transferring electrons. The LUMO level of the substance with an electron-transport property contained in the electron relay layer 118 is preferably between the LUMO level of an acceptor substance in the p-type layer 117 and the LUMO level of a substance in a layer of the electron-transport layer 114 that is in contact with the charge generation layer 116. As a concrete value of the energy level, the LUMO level of the substance with an electron-transport property in the electron relay layer 118 is higher than or equal to -5.0 eV, preferably higher than or equal to -5.0 eV and lower than or equal to -3.0 eV.It should be noted that as a substance having an electron-transport property in the electron-transmitting layer 118, a phthalocyanine-based material such as phthalocyanine (abbreviation: H2Pc), copper phthalocyanine (abbreviation: CuPc) or zinc phthalocyanine (abbreviation: ZnPc), or a metal complex having a metal-oxygen bond and an aromatic ligand is preferably used.

[0127] A substance with a high electron injection property can be used for the electron injection buffer layer 119. For example, an alkali metal, an alkaline earth metal, a rare earth metal, or a compound thereof (an alkali metal compound (including an oxide such as lithium oxide, a halide such as lithium fluoride, and a carbonate such as lithium carbonate and cesium carbonate), an alkaline earth metal compound (including an oxide, a halide, and a carbonate), or a rare earth metal compound (including an oxide, a halide, and a carbonate)) can be used.

[0128] In the case where the electron injection buffer layer 119 contains the substance having an electron-transport property and a donor substance, an organic compound such as tetrathianaphthacene (abbreviation: TTN), nickelocene, or decamethylnickelocene can be used as the donor substance, as can an alkali metal, an alkaline earth metal, a rare earth metal, a compound thereof (e.g., an alkali metal compound (including an oxide such as lithium oxide, a halide such as lithium fluoride, and a carbonate such as lithium carbonate and cesium carbonate), an alkaline earth metal compound (including an oxide, a halide, and a carbonate), or a rare earth metal compound (including an oxide, a halide, and a carbonate)). As the substance having an electron-transport property, a material similar to the above-described material for the electron-transport layer 114 can be used.

[0129] The second electrode 102 is an electrode including a cathode. The second electrode 102 may have a multilayer structure, in which case a layer in contact with the organic compound layer 103 serves as a cathode. For the substance constituting the cathode, a metal, an alloy, an electrically conductive compound, or a mixture thereof, each having a low work function (particularly, a work function of less than or equal to 3.8 eV), or the like, may be used. Specific examples of such a cathode material include elements belonging to Group 1 or 2 of the Periodic Table, for example, alkali metals such as selenium, tin, or the like. B. Lithium (Li) or cesium (Cs), magnesium (Mg), calcium (Ca) and strontium (Sr), alloys containing these elements (e.g. MgAg and AlLi), compounds (e.g. lithium fluoride (LiF), cesium fluoride (CsF) and calcium fluoride (CaF2)), rare earth metals, such asEuropium (Eu) and ytterbium (Yb), and alloys containing these rare earth metals. However, when the electron injection layer 115 or a thin film of the above low work function material is provided between the second electrode 102 and the electron transport layer, various conductive materials, such as Al, Ag, ITO, or indium oxide-tin oxide containing silicon or silicon oxide, can be used for the cathode regardless of the work function.

[0130] When the second electrode 102 is formed using a material having visible light transmittance, the light-emitting device can emit light from the second electrode 102 side.

[0131] Films of these conductive materials can be formed by a dry process such as a vacuum evaporation method or a sputtering method, an inkjet method, a spin-coating method, or the like. Alternatively, a wet process using a sol-gel method or a wet process using a paste of a metal material can be used.

[0132] Various methods can be used to form the organic compound layer 103, regardless of whether it is a dry process or a wet process. For example, a vacuum evaporation method, a gravure printing method, an offset printing method, a screen printing method, an inkjet method, a spin coating method, or the like can be used.

[0133] Different methods can be used to form the electrodes or layers described above.

[0134] Next, an embodiment of a light-emitting device having a structure in which a plurality of light-emitting units are arranged one above the other (also referred to as a multi-layer element or a tandem element) will be described with reference to Fig. 1C. This organic EL element is an organic EL element comprising a plurality of light-emitting units between an anode and a cathode. A light-emitting unit has substantially the same structure as the organic compound layer 103 shown in Fig. 1A. In other words, the Fig. The organic EL element shown in Figure 1C is an organic EL element comprising a plurality of light-emitting units, and the organic EL element shown in Figure 1C is Fig. 1A or Fig. The organic EL element shown in Figure 1B is an organic EL element comprising a single light-emitting unit.

[0135] In Fig. 1C, a first light-emitting unit 511 and a second light-emitting unit 512 are stacked between a first electrode 501 and a second electrode 502, and a charge generation layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The first electrode 501 and the second electrode 502 correspond to the first electrode 101 and the second electrode 102, respectively, in Fig. 1A, and to the description of Fig. 1A. Furthermore, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same structure or different structures.

[0136] The charge generation layer 513 has a function of injecting electrons into one of the light-emitting units and injecting holes into the other light-emitting unit when a voltage is applied between the first electrode 501 and the second electrode 502. That is, in Fig. 1C, the charge generation layer 513 injects electrons into the first light-emitting unit 511 and holes into the second light-emitting unit 512 when a voltage is applied such that the potential of the anode is higher than the potential of the cathode.

[0137] The charge generation layer 513 preferably has a structure similar to that of the Fig. 1B. A composite material of an organic compound and a metal oxide has excellent charge-carrier injection properties and excellent charge-carrier transport properties; accordingly, low-voltage operation and low-current operation can be achieved. In the case where a surface of a light-emitting device on the anode side is in contact with the charge-generation layer 513, the charge-generation layer 513 can also serve as a hole-injection layer of the light-emitting device; therefore, a hole-injection layer is not necessarily provided in the light-emitting device.

[0138] In the case where the charge generation layer 513 includes the electron injection buffer layer 119, the electron injection buffer layer 119 serves as an electron injection layer in the light-emitting unit on the anode side; therefore, an electron injection layer is not necessarily formed in the light-emitting unit on the anode side.

[0139] The organic EL element, which comprises two light-emitting units, is based on Fig. 1C; however, an embodiment of the present invention can be equally applied to an organic EL element in which three or more light-emitting units are stacked one above the other. As in the organic EL element of this embodiment, when a plurality of light-emitting units separated by the charge generation layer 513 are arranged between a pair of electrodes, an element capable of emitting light with high luminance at a low current density and having a longer lifetime can be obtained. A light-emitting device capable of operating at a low voltage and having low power consumption can be provided.

[0140] Furthermore, when the emission colors of light-emitting units differ from each other, light emission of a desired color can be obtained from the organic EL element as a whole. For example, in an organic EL element comprising two light-emitting units, the emission colors of the first light-emitting unit may be red and green, and the emission color of the second light-emitting unit may be blue, so that the organic EL element can emit white light as a whole.

[0141] The above-described electrodes and layers, such as the organic compound layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the charge generation layer, can be formed by a method such as an evaporation method (including a vacuum evaporation method), a droplet ejection method (also referred to as an inkjet method), a coating method, or a gravure printing method. A low-molecular material, a medium-molecular material (including an oligomer and a dendrimer), or a high-molecular material can be included in the layers or electrodes.

[0142] Fig. 2 illustrates two adjacent light-emitting devices (a light-emitting device 130a and a light-emitting device 130b) among a group 130A of a plurality of the light-emitting devices 130 in a display device of one embodiment of the present invention. Note that the display device includes a first electrode group 101A of a plurality of the first electrodes 101 formed over the insulating layer 175, the second electrode 102, and a first layer group 135A of a plurality of first layers 135, and that in the light-emitting device, at least the first electrode 101, the first layer 135, and the second electrode 102 overlap with each other.

[0143] The light-emitting device 130a includes an organic interconnect layer 103a between a first electrode 101a above the insulating layer 175 and the second electrode 102 facing the first electrode 101a. The illustrated organic interconnect layer 103a includes a hole-injection layer 111a, a hole-transport layer 112a, a light-emitting layer 113a, an electron-transport layer 114a, and the electron-injection layer 115, but it may have a different multilayer structure. The organic interconnect layer 103a includes a first layer 135a that is unique to the light-emitting device and may further include a common layer 136 shared by the plurality of light-emitting devices. Fig. 2, the hole-injection layer 111a, the hole-transport layer 112a, the light-emitting layer 113a, and the electron-transport layer 114a correspond to the first layer, and the electron-injection layer 115 corresponds to the common layer. Note that the electron-injection layer 115 may be single for the light-emitting device, and the entire organic compound layer 103a may be used as the first layer 135a.

[0144] The light-emitting device 130b includes an organic interconnect layer 103b between a first electrode 101b above the insulating layer 175 and the second electrode 102 facing the first electrode 101b. The illustrated organic interconnect layer 103b includes a hole-injection layer 111b, a hole-transport layer 112b, a light-emitting layer 113b, an electron-transport layer 114b, and the electron-injection layer 115, but it may have a different multilayer structure. Fig. 2, the hole injection layer 111b, the hole transport layer 112b, the light-emitting layer 113b, and the electron transport layer 114b correspond to the first layer 135b, and the electron injection layer 115 corresponds to the common layer 136. Note that the electron injection layer 115 for the light-emitting device may be single, and the entire organic compound layer 103b may be used as the first layer 135b.

[0145] The electron-injection layer 115 and the second electrode 102 are each preferably a continuous layer (common layer) shared by the light-emitting device 130a and the light-emitting device 130b. The organic compound layer 103a and the organic compound layer 103b excluding the electron-injection layer 115, that is, the first layers, are processed separately by a photolithography process after the formation of the electron-transport layer 114a and after the formation of the electron-transport layer 114b; therefore, they are independent of each other. Since end portions (contours) of the organic compound layer 103a excluding the electron-injection layer 115 are processed by a photolithography process, the end portions are substantially aligned with respect to the substrate.Furthermore, since end portions (contours) of the organic interconnect layer 103b other than the electron injection layer 115 are processed by a photolithography process, the end portions are substantially aligned with respect to the substrate. After the formation of the electron transport layer 114a and the electron transport layer 114b, a heating step is performed in a photolithography process.

[0146] Since the organic compound layers are processed by a photolithography method, the distance d between the first electrode 101a and the first electrode 101b can be smaller than that in the case of mask evaporation. The distance d can be greater than or equal to 2 µm and less than or equal to 5 µm. (Embodiment 3)

[0147] In this embodiment, a mode will be described in which the organic semiconductor device of one embodiment of the present invention is a light-emitting device that can be used as a display element of a display device.

[0148] As in Fig. 3A and Fig. 3B, the plurality of light-emitting devices 130 are formed over the insulating layer 175 to form a display device.

[0149] The display device comprises a pixel section 177 in which a plurality of pixels 178 are arranged in a matrix. The pixel 178 comprises a subpixel 110R, a subpixel 110G, and a subpixel 110B.

[0150] For example, in this specification and the like, the description common to subpixels 110R, 110G, and 110B is sometimes referred to collectively as "subpixel 110." Regarding other components that are distinguishable from each other using alphabetic characters, their commonalities are sometimes described using reference numerals without the alphabetic characters.

[0151] Subpixel 110R emits red light, subpixel 110G emits green light, and subpixel 110B emits blue light. In this way, an image can be displayed on pixel portion 177. Note that, in this embodiment, three colors of red (R), green (G), and blue (B) are given as examples of subpixel light colors, but subpixels of a different combination of colors may be used. The type of subpixels is not limited to three and may be four or more. Examples of four subpixels include subpixels emitting light of four colors of R, G, B, and white (W), or four colors of R, G, B, and Y, and four subpixels emitting light of R, G, B, and infrared (IR).

[0152] In this description and the like, the row direction and column direction are sometimes referred to as the X direction and the Y direction, respectively. The X direction and the Y direction intersect and are perpendicular to each other, for example.

[0153] Fig. 3A illustrates an example in which subpixels of different colors are arranged in the X direction and subpixels of the same color are arranged in the Y direction. Note that subpixels of different colors may be arranged in the Y direction, and subpixels of the same color may be arranged in the X direction.

[0154] A connecting portion 140 is provided outside the pixel portion 177, and a region 141 may also be provided. The region 141 is provided between the pixel portion 177 and the connecting portion 140. The organic interconnect layer 103 is provided in the region 141. A conductive layer 151C is provided in the connecting portion 140.

[0155] Although Fig. 3 illustrates an example in which the region 141 and the connecting portion 140 are located on the right side of the pixel portion 177, the positions of the region 141 and the connecting portion 140 are not particularly limited. The number of regions 141 and connecting portions 140 may be one or more.

[0156] Fig. 3B is a cross-sectional view taken along a dot-dash line A1-A2 in Fig. 3A. As in Fig. As shown in Figure 3A, the display device includes an insulating layer 171, a conductive layer 172 over the insulating layer 171, an insulating layer 173 over the insulating layer 171 and the conductive layer 172, an insulating layer 174 over the insulating layer 173, and the insulating layer 175 over the insulating layer 174. The insulating layer 171 is provided over a substrate (not shown). An opening reaching the conductive layer 172 is provided in the insulating layer 175, the insulating layer 174, and the insulating layer 173, and a terminal plug 176 is provided to fill the opening.

[0157] In the pixel portion 177, the light-emitting device 130 is provided over the insulating layer 175 and the terminal plug 176. A protective layer 131 is further provided over the light-emitting device 130. A substrate 120 is secured with a resin layer 122 over the protective layer 131. In a region between adjacent light-emitting devices 130, an inorganic insulating layer 125 and an insulating layer 127 are preferably provided over the inorganic insulating layer 125.

[0158] Although Fig. While FIG. 3B illustrates a plurality of cross-sections of the inorganic insulating layer 125 and the insulating layer 127, the inorganic insulating layer 125 and the insulating layer 127 are each a single continuous layer when the display device is viewed from above. In other words, the insulating layer 127 preferably includes an opening portion above a first electrode.

[0159] In Fig. 3B, a light-emitting device 130R, a light-emitting device 130G, and a light-emitting device 130B are each depicted as a light-emitting device 130. The light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B emit light of different colors. For example, the light-emitting device 130R may emit red light, the light-emitting device 130G may emit green light, and the light-emitting device 130B may emit blue light. Alternatively, the light-emitting device 130R, the light-emitting device 130G, or the light-emitting device 130B may emit visible light of another color or infrared light. It can be said that in Fig. 3B, the light-emitting device 130R and the light-emitting device 130G are adjacent light-emitting devices, and the light-emitting device 130G and the light-emitting device 130B are adjacent light-emitting devices.

[0160] For example, the display device of one embodiment of the present invention may have a top-emission structure in which light is emitted in the direction opposite to a substrate over which the light-emitting device is formed. Note that the display device of one embodiment of the present invention may have a bottom-emission structure.

[0161] The light-emitting device 130R emits red light and preferably has any of the structures described in Embodiment 1 or 2. The light-emitting device 130R includes a first electrode (pixel electrode) comprising a conductive layer 151R and a conductive layer 152R, a first layer 135R over the first electrode, a common layer 136 over the first layer 135R, and the second electrode (common electrode) 102 over the common layer 136. The common layer 136 is preferably an electron injection layer.

[0162] The light-emitting device 130G emits green light and may preferably have any of the structures shown in Embodiment 1 or 2. The light-emitting device 130G includes a first electrode (pixel electrode) comprising a conductive layer 151G and a conductive layer 152G, a first layer 135G over the first electrode, the common layer 136 over the first layer 135G, and the second electrode (common electrode) 102 over the common layer 136. The common layer 136 is preferably an electron injection layer.

[0163] The light-emitting device 130B emits blue light and preferably has any of the structures shown in Embodiment 1 or 2. The light-emitting device 130B includes a first electrode (pixel electrode) comprising a conductive layer 151B and a conductive layer 152B, a first layer 135B over the first electrode, the common layer 136 over the first layer 135B, and the second electrode (common electrode) 102 over the common layer 136. The common layer 136 is preferably an electron injection layer.

[0164] In the light-emitting device, one of the pixel electrode (first electrode) and the common electrode (second electrode) serves as the anode, and the other serves as the cathode. In this embodiment, the description is made assuming that the pixel electrode serves as the anode and the common electrode serves as the cathode, unless otherwise specified.

[0165] The first layer 135R, the first layer 135G, and the first layer 135B are island-shaped layers that are independent of each other for the respective colors. It is preferable that the first layer 135R, the first layer 135G, and the first layer 135B do not overlap with each other. The first layers included in the plurality of light-emitting devices 130 in the light-emitting device, such as the first layer 135R, the first layer 135G, and the first layer 135B, are collectively referred to as the first layer group 135A in some cases. By providing the first layer group 135A in an island-like manner in each of the light-emitting devices 130, leakage current between the adjacent light-emitting devices 130 can be suppressed even in a display device with high image sharpness. Thus, crosstalk can be prevented, so that a display device with very high contrast can be achieved.In particular, a display device with high power efficiency at low luminance can be achieved.

[0166] The island-shaped first layer group 135A is formed by forming an EL film for each emission color and processing the EL film by a photolithography method.

[0167] The first layer 135 is preferably provided to cover the top and side surfaces of the first electrode (pixel electrode) 101 of the light-emitting device 130. Thus, the aperture ratio of the display device can be slightly increased compared to the structure in which an end portion of the first layer 135 is positioned further inside than an end portion of the pixel electrode. By covering the side surface of the pixel electrode of the light-emitting device 130 with the first layer 135, the first electrode 101 can be prevented from coming into contact with the second electrode 102; thus, a short circuit of the light-emitting device 130 can be prevented.

[0168] In the display device of one embodiment of the present invention, the first electrode (pixel electrode) 101 of the light-emitting device preferably has a multi-layer structure. For example, in the Fig. 3B, the first electrode 101 of the light-emitting device 130 has a layer arrangement of the conductive layer 151 on the side of the substrate 171 and the conductive layer 152 on the side of the organic compound layer.

[0169] For example, a metal material may be used for the conductive layer 151. Specifically, for example, a metal such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), or neodymium (Nd), or an alloy containing these in a suitable combination may be used.

[0170] For the conductive layer 152, an oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, a conductive oxide containing one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, indium zinc oxide containing silicon, and the like is preferably used. In particular, an indium tin oxide containing silicon can be suitably used for the conductive layer 152 because it has, for example, a work function of greater than or equal to 4.0 eV.

[0171] The conductive layer 151 and the conductive layer 152 may each be a stack of multiple layers containing different materials. In this case, the conductive layer 151 may include a layer formed using a material usable for the conductive layer 152, such as a conductive oxide. Furthermore, the conductive layer 152 may include a layer formed using a material usable for the conductive layer 151, such as a metal material. In the case where the conductive layer 151 is a stack of two or more layers, for example, a layer in contact with the conductive layer 152 may be formed using a material usable for the conductive layer 152.

[0172] An end portion of the conductive layer 151 preferably has a tapered shape. In particular, the end portion of the conductive layer 151 preferably has a tapered shape with a taper angle of less than 90°. In this case, the conductive layer 152 provided along the side surface of the conductive layer 151 also has a tapered shape. When the side surface of the conductive layer 152 has a tapered shape, the coverage with the first layer 135 provided along the side surface of the conductive layer 152 can be improved.

[0173] An example of a manufacturing process for a display device with the Fig. 3A shown structure using Fig. 4 to Fig. 9 described. [Example 1 of the manufacturing process]

[0174] A thin film (e.g., an insulating film, a semiconductor film, or a conductive film) included in the display device may be formed by a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an ALD method, or the like.

[0175] A thin film (e.g., an insulating film, a semiconductor film, and a conductive film) included in the display device may alternatively be formed by a wet method such as spin coating, dipping, spray coating, inkjet printing, dispensing, screen printing, offset printing, a doctor blade cutting method, gap coating, roll coating, curtain coating, or doctor blade coating.

[0176] Alternatively, a thin film included in the display device can be processed, for example, by a photolithography process.

[0177] For example, i-line light (with a wavelength of 365 nm), g-line light (with a wavelength of 436 nm), h-line light (with a wavelength of 405 nm), or a mixture of these can be used as exposure light in a photolithography process. Alternatively, ultraviolet light, KrF laser light, ArF laser light, or the like can be used. Exposure can be performed using a liquid immersion exposure technique. Extreme ultraviolet (EUV) light or X-rays can also be used as exposure light. An electron beam can also be used instead of exposure light.

[0178] To etch a thin film, for example, a dry etching process, a wet etching process or a sandblasting process can be used.

[0179] As in Fig. As shown in Figure 4A, the insulating layer 171 is formed over a substrate (not shown). Next, the conductive layer 172 and a conductive layer 179 are formed over the insulating layer 171, and the insulating layer 173 is formed over the insulating layer 171 to cover the conductive layer 172 and the conductive layer 179. Then, the insulating layer 174 is formed over the insulating layer 173, and the insulating layer 175 is formed over the insulating layer 174.

[0180] As the substrate, a substrate with heat resistance high enough to withstand at least one subsequent heat treatment can be used. For example, it is possible to use a glass substrate; a quartz substrate; a sapphire substrate; a ceramic substrate; an organic resin substrate; or a semiconductor substrate such as a single-crystal semiconductor substrate or a polycrystalline semiconductor substrate made of silicon, silicon carbide, or the like, a compound semiconductor substrate made of silicon germanium or the like, or an SOI substrate.

[0181] Next, as in Fig. As shown in Figure 4A, openings reaching the conductive layer 172 are formed in the insulating layer 175, the insulating layer 174, and the insulating layer 173. Then, the terminal plug 176 is formed to fill the opening.

[0182] Next, as in Fig. As shown in Figure 4A, a conductive film 151f, which later becomes the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, and the conductive layer 151C, is formed over the terminal plug 176 and the insulating layer 175. For the conductive film 151f, for example, a metal material can be used.

[0183] Subsequently, a photoresist mask 191, as shown in Fig. 4A, is formed over the conductive film 151 cf. The photoresist mask 191 can be formed by applying a light-sensitive material (photoresist), exposing it, and developing it.

[0184] Then, as in Fig. 4B, the conductive film 151f is removed, for example, in an area that does not overlap with the photoresist mask 191. In this way, the conductive layer 151 is formed.

[0185] Next, the photoresist mask 191 is removed as shown in Fig. 4C. The photoresist mask 191 can be removed, for example, by ashing using oxygen plasma.

[0186] Then, as in Fig. 4D, an insulating film 156f, which later becomes an insulating layer 156R, an insulating layer 156G, an insulating layer 156B, and an insulating layer 156C, is formed over the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, the conductive layer 151C, and the insulating layer 156F.

[0187] For the insulating film 156f, for example, an inorganic insulating film such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film such as silicon oxynitride can be used.

[0188] Then, as in Fig. 4E, the insulating film 156f is processed to form the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, and the insulating layer 156C.

[0189] Next, as in Fig. 5A, a conductive film 152f is formed over the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, and the conductive layer 151C, as well as the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, the insulating layer 156C, and the insulating layer 156S.

[0190] For example, a conductive oxide can be used for the conductive film 152f. The conductive film 152f can have a multilayer structure.

[0191] Then, as in Fig. 5B, the conductive film 152f is processed to form the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C.

[0192] Next, as in Fig. 5C, an organic compound film 103Rf is formed over the conductive layer 152R, the conductive layer 152G and the conductive layer 152B, and the insulating layer 175. As shown in Fig. 5C, the organic compound film 103Rf is not formed over the conductive layer 152C.

[0193] Then a sacrificial film 158Rf and a mask film 159Rf are formed as in Fig. 5C.

[0194] By providing the sacrificial film 158Rf over the organic compound film 103Rf, damage to the organic compound film 103Rf during the manufacturing process of the display device can be reduced and the reliability of the light-emitting device can be increased.

[0195] For the sacrificial film 158Rf, a film with high resistance to the processing conditions of the organic compound film 103Rf is used, particularly a film with high etch selectivity with respect to the organic compound film 103Rf. For the mask film 159Rf, a film with high etch selectivity with respect to the sacrificial film 158Rf is used.

[0196] The sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the upper temperature limit of the organic compound film 103Rf. The typical substrate temperatures during the formation of the sacrificial film 158Rf and the mask film 159Rf are respectively higher than or equal to 100°C and lower than or equal to 200°C, preferably higher than or equal to 100°C and lower than or equal to 150°C, more preferably higher than or equal to 100°C and lower than or equal to 120°C. The light-emitting device of one embodiment of the present invention contains a first organic compound and therefore enables a display device with high display quality even when manufactured by a higher-temperature heating process.

[0197] The sacrificial film 158Rf and the mask film 159Rf are preferably films that can be removed by a wet etching process or a dry etching process.

[0198] Note that the sacrificial film 158Rf formed over and in contact with the organic compound film 103Rf is preferably formed by a formation method that is less likely to damage the organic compound film 103Rf than the formation method of the mask film 159Rf. For example, the sacrificial film 158Rf is preferably formed by an ALD (atomic layer deposition) method or a vacuum evaporation method rather than a sputtering method.

[0199] As both the sacrificial film 158Rf and the mask film 159Rf, for example, one or more of a metal film, an alloy film, a metal oxide film, a semiconductor film, an organic insulating film, and an inorganic insulating film can be used.

[0200] For each of the sacrificial film 158Rf and the mask film 159Rf, for example, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, or tantalum, or an alloy material containing this metal material, can be used. In particular, a low-melting-point material such as aluminum, silver, or the like is preferably used. Preferably, a metal material capable of shielding ultraviolet rays is used for the sacrificial film 158Rf and / or the mask film 159Rf. In this case, the organic compound film 103Rf can be prevented from being irradiated with ultraviolet rays during exposure for patterning, and deterioration of the organic compound film 103Rf can be prevented.

[0201] For the sacrificial film 158Rf and the mask film 159Rf, a metal oxide such as an In-Ga-Zn oxide, an indium oxide, an In-Zn oxide, an In-Sn oxide, an indium titanium oxide (In-Ti oxide), an indium tin zinc oxide (In-Sn-Zn oxide), an indium titanium zinc oxide (In-Ti-Zn oxide), an indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), or an indium tin oxide containing silicon can be used, respectively.

[0202] Furthermore, in the above metal oxide, an element M (the element M is one or more selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten and magnesium) may be used instead of gallium.

[0203] The sacrificial film 158Rf and the mask film 159Rf are preferably formed using, for example, a semiconductor material such as silicon or germanium for excellent compatibility with a semiconductor manufacturing process. Alternatively, a compound containing the above semiconductor material may be used.

[0204] Any of various inorganic insulating films can be used as both the sacrificial film 158Rf and the mask film 159Rf. In particular, an insulating oxide film is preferred because its adhesion to the organic compound film 103Rf is higher than that of an insulating nitride film.

[0205] Then, as in Fig. 5C, a photoresist mask 190R is formed. The photoresist mask 190R can be formed by applying a light-sensitive material (photoresist), exposure, and development.

[0206] The photoresist mask 190R is provided at a position overlapping with the conductive layer 152R. It is preferable that the photoresist mask 190R also be provided at a position overlapping with the conductive layer 152C. Thus, the conductive layer 152C can be prevented from being damaged during the manufacturing process of the display device.

[0207] Then, as in Fig. 5D, using the photoresist mask 190R, the mask film 159Rf is partially removed to form a mask layer 159R. The mask layer 159R remains over the conductive layer 152R and the conductive layer 152C. Then, the photoresist mask 190R is removed. Then, the sacrificial film 158Rf is partially removed using the mask layer 159R as a mask (also called a hard mask), thereby forming a sacrificial layer 158R.

[0208] By using a wet etching method, damage to the organic compound film 103Rf during processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced more than when using a dry etching method. When using a wet etching method, it is preferable to use, for example, an alkaline aqueous solution such as a developing solution or an aqueous tetramethylammonium hydroxide (TMAH) solution, diluted hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or an acidic aqueous solution such as a chemical solution containing a mixed liquid of any of these.

[0209] In case of using a dry etching method in processing the sacrificial film 158Rf, the deterioration of the organic compound film 103Rf can be prevented by not using oxygen-containing gas as the etching gas.

[0210] The photoresist mask 190R can be removed by a similar method to that of the photoresist mask 191.

[0211] Next, as in Fig. 5D, the organic compound film 103Rf is processed to form the first layer 135R. For example, the organic compound film 103Rf is partially removed using the mask layer 159R and the sacrificial layer 158R as a hard mask, thereby forming the first layer 135R.

[0212] Accordingly, as in Fig. 5D illustrates a multilayer structure of the first layer 135R, the sacrificial layer 158R, and the mask layer 159R over the conductive layer 152R. The conductive layer 152G and the conductive layer 152B are exposed.

[0213] The organic compound film 103Rf is preferably processed by anisotropic etching. Anisotropic dry etching is particularly preferred. Alternatively, wet etching can be used.

[0214] In case of using a dry etching process, deterioration of the organic compound film 103Rf can be prevented by not using an oxygen-containing gas as the etching gas.

[0215] An oxygen-containing gas can be used as the etching gas. When the etching gas contains oxygen, the etching rate can be increased. Therefore, etching can be performed under low-power conditions while maintaining a sufficiently high etching rate. Accordingly, damage to the organic compound film 103Rf can be reduced. Furthermore, defects such as adhesion of a reaction product generated during etching can be prevented.

[0216] When using a dry etching method, for example, a gas containing one or more of H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or Group 18 elements such as He or Ar is preferably used as the etching gas. Alternatively, a gas containing oxygen and at least one of these is preferably used as the etching gas. Alternatively, an oxygen gas may be used as the etching gas.

[0217] Then, as in Fig. 6A, an organic compound film 103Gf is formed, which later becomes the first layer 135G.

[0218] The organic compound film 103Gf can be formed by a method similar to that used to form the organic compound film 103Rf. The organic compound film 103Gf can have a structure similar to that of the organic compound film 103Rf.

[0219] Then, as in Fig. 6A, a sacrificial film 158Gf and a mask film 159Gf are formed in this order. Next, a photoresist mask 190G is formed. The materials and formation methods of the sacrificial film 158Gf and the mask film 159Gf are similar to those that can be used for the sacrificial film 158Rf and the mask film 159Rf. The material and formation method of the photoresist mask 190G are similar to those that can be used for the photoresist mask 190R.

[0220] The photoresist mask 190G is provided at a position overlapping with the conductive layer 152G.

[0221] Then, as in Fig. 6B, using the photoresist mask 190G, the mask film 159Gf is partially removed to form the mask layer 159G. The mask layer 159G remains over the conductive layer 152G. Then, the photoresist mask 190G is removed. Then, the sacrificial film 158Gf is partially removed using the mask layer 159G as a mask, thereby forming the sacrificial layer 158G. Next, the organic interconnect film 103Gf is processed to form the first layer 135G.

[0222] Then, as in Fig. 6C, an organic compound film 103Bf was formed.

[0223] The organic compound film 103Bf can be formed by a similar method to that used to form the organic compound film 103Rf. The organic compound film 103Bf can have a similar structure to that of the organic compound film 103Rf.

[0224] Then, as in Fig. 6C, a sacrificial film 158Bf and a mask film 159Bf are formed in this order. Subsequently, a photoresist mask 190B is formed. The materials and formation methods of the sacrificial film 158Bf and the mask film 159Bf are similar to those that can be used for the sacrificial film 158Rf and the mask film 159Rf. The material and formation method of the photoresist mask 190B are similar to those that can be used for the photoresist mask 190R.

[0225] The photoresist mask 190B is provided at a position overlapping with the conductive layer 152B.

[0226] Then, as in Fig. 6D, using the photoresist mask 190B, the mask film 159Bf is partially removed to form a mask layer 159B. The mask layer 159B remains over the conductive layer 152B. Then, the photoresist mask 190B is removed. Then, the sacrificial film 158Bf is partially removed using the mask layer 159B as a mask, thereby forming the sacrificial layer 158B. Next, the organic compound film 103Bf is processed to form the first layer 135B. For example, the organic compound film 103Bf is partially removed using the mask layer 159B and the sacrificial layer 158B as a hard mask, thereby forming the first layer 135B.

[0227] Accordingly, as in Fig. 6D illustrates a multilayer structure of the first layer 135B, the sacrificial layer 158B, and the mask layer 159B over the conductive layer 152B. The mask layer 159R and the mask layer 159G are exposed.

[0228] It should be noted that the side surfaces of the first layer 135R, the first layer 135G, and the first layer 135B are preferably each perpendicular or substantially perpendicular to the formation surface. For example, the angle between the formation surface and these respective side surfaces is preferably greater than or equal to 60° and less than or equal to 90°.

[0229] As described above, a distance between two adjacent layers among the first layer 135R, the first layer 135G, and the first layer 135B formed by a photolithography method can be shortened to less than or equal to 8 μm, less than or equal to 5 μm, less than or equal to 3 μm, less than or equal to 2 μm, or less than or equal to 1 μm. Here, the distance can be determined, for example, as the distance between two adjacent, facing end portions of the first layer 135R, the first layer 135G, and the first layer 135B. By shortening the distance between the island-shaped organic compound layers in this way, a display device with high image sharpness and a high aperture ratio can be provided.Furthermore, the distance between the first electrodes of adjacent light-emitting devices can also be shortened to, for example, less than or equal to 10 µm, less than or equal to 8 µm, less than or equal to 5 µm, less than or equal to 3 µm, or less than or equal to 2 µm. Note that the distance between the first electrodes of adjacent light-emitting devices is preferably greater than or equal to 2 µm and less than or equal to 5 µm.

[0230] Next, as in Fig. 7A, the mask layer 159R, the mask layer 159G and the mask layer 159B are preferably removed.

[0231] A similar method to that used in the mask layer processing process can be used for the mask layer removal process. In particular, using a wet etching process can reduce damage to the first layers 135 during mask layer removal more than using a dry etching process.

[0232] The mask layers can be removed by dissolving them in a polar solvent, such as water or an alcohol. Examples of alcohols include ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), glycerin, or the like.

[0233] After removing the mask layers, a drying treatment can be performed to remove water adsorbed on surfaces. For example, a heat treatment can be performed in an inert gas atmosphere or in a reduced-pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 120°C or lower. Drying at a lower temperature is possible under reduced pressure, which is preferable.

[0234] Next, an inorganic insulating film 125f is formed as shown in Fig. 7B.

[0235] Then, as in Fig. 7C, an insulating film 127f, which later becomes the insulating layer 127, is formed over the inorganic insulating film 125f.

[0236] The substrate temperature in the formation of the inorganic insulating film 125f and the insulating film 127f is preferably higher than or equal to 60°C, higher than or equal to 80°C, higher than or equal to 100°C, or higher than or equal to 120°C and lower than or equal to 200°C, lower than or equal to 180°C, lower than or equal to 160°C, lower than or equal to 150°C, or lower than or equal to 140°C.

[0237] As the inorganic insulating film 125f, an insulating film having a thickness of greater than or equal to 3 nm, greater than or equal to 5 nm, or greater than or equal to 10 nm and less than or equal to 200 nm, less than or equal to 150 nm, less than or equal to 100 nm, or less than or equal to 50 nm is preferably formed within the above substrate temperature range.

[0238] The inorganic insulating film 125f is preferably formed, for example, by an ALD method. An ALD method is preferably used because it can reduce formation damage and form a film with high coverage, which is preferable. As the inorganic insulating film 125f, an alumina film, for example, is preferably formed by an ALD method.

[0239] The insulating film 127f is preferably formed by the aforementioned wet method. The insulating film 127f is preferably formed, for example, by spin coating using a photosensitive material, and more preferably, using a photosensitive resin composition containing an acrylic resin.

[0240] Subsequently, exposure is performed, and the insulating film 127f is partially exposed to visible light or ultraviolet rays. The insulating layer 127 is formed in regions located between any two of the conductive layer 152R, the conductive layer 152G, and the conductive layer 152B, as well as around the conductive layer 152C.

[0241] The width of the insulating layer 127 to be formed later can be controlled by the exposed area of ​​the insulating film 127f. In this embodiment, the processing is performed such that the insulating layer 127 includes a portion that overlaps with the upper surface of the conductive layer 151.

[0242] Exposure light preferably contains an i-line (wavelength: 365 nm). Furthermore, exposure light may contain at least one g-line (wavelength: 436 nm) and / or one h-line (wavelength: 405 nm).

[0243] Then, as in Fig. 8A, the exposed portion of the insulating film 127f is removed by development, thereby forming an insulating layer 127a.

[0244] Then, as in Fig. 8B, an etching treatment is performed using the insulating layer 127a as a mask, thereby partially removing the inorganic insulating film 125f and reducing the film thickness of parts of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. Thus, the inorganic insulating layer 125 is formed under the insulating layer 127a. In addition, the surfaces of the thin portions of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are exposed. Note that the etching treatment using the insulating layer 127a as a mask may be referred to as the first etching treatment hereinafter.

[0245] The first etching treatment can be performed by dry etching or wet etching. Note that when the inorganic insulating film 125f is formed using a material similar to that used for the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the first etching treatment can be performed collectively, which is preferable.

[0246] When performing dry etching, a chlorine-based gas is preferably used. As the chlorine-based gas, one of Cl2, BCl3, SiCl4, CCl4, and the like, or a mixture of two or more of these, can be used. In addition, an oxygen gas, a hydrogen gas, a helium gas, an argon gas, or the like, or a mixture of two or more of these, can be added to the above chlorine-based gas as needed. By using dry etching, thin portions of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B can be formed with favorable in-plane uniformity.

[0247] A dry etching device comprising a high-density plasma source can be used as the dry etching device. For example, an inductively coupled plasma (ICP) etching device can be used as the dry etching device comprising a high-density plasma source. Alternatively, a capacitively coupled plasma (CCP) etching device comprising parallel plate electrodes can be used.

[0248] The first etching treatment is preferably performed by wet etching. By using a wet etching method, damage to the first layer 135R, the first layer 135G, and the first layer 135B can be reduced more than when using a dry etching method. For example, the wet etching can be performed using an alkaline solution. For example, TMAH, which is an alkaline solution, can be used for the wet etching of an aluminum oxide film. Alternatively, an acid solution containing fluoride can also be used. In this case, paddle wet etching can be performed. Note that when the inorganic insulating film 125f is formed using a material similar to that used for the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the above etching treatment can be performed collectively, which is preferable.

[0249] The sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are not completely removed by the first etching treatment, and the etching treatment is interrupted when the thicknesses of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are reduced. The respective sacrificial layer 158R, the respective sacrificial layer 158G, and the respective sacrificial layer 158B thus remain above the first layer 135R, the first layer 135G, and the first layer 135B, which can prevent the first layer 135R, the first layer 135G, and the first layer 135B from being damaged by treatment in a later step.

[0250] Subsequently, exposure is preferably performed on the entire substrate so that the insulating layer 127a is irradiated with visible light or ultraviolet rays. The energy density for exposure may preferably be higher than 0 mJ / cm 2and less than or equal to 800 mJ / cm 2 , preferably higher than 0 mJ / cm 2 and less than or equal to 500 mJ / cm 2 By performing such exposure after development, the degree of transparency of the insulating layer 127a can be increased in some cases. Furthermore, in some cases, it is possible to lower the substrate temperature required in a later step for a heat treatment to change the shape of the insulating layer 127a into a tapered shape.

[0251] Here, if an insulating barrier layer against oxygen (e.g., an aluminum oxide film) is provided as each of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the diffusion of oxygen into the first layer 135R, the first layer 135G, and the first layer 135B can be suppressed.

[0252] Subsequently, a heat treatment (also referred to as post-baking) is carried out. The heat treatment allows the insulating layer 127a to be deformed into the insulating layer 127, whose side surface has a tapered shape ( Fig. 8C). The heat treatment is performed at a lower temperature than the upper temperature limit of the organic compound layer. The heat treatment can be performed at a substrate temperature of higher than or equal to 50°C and lower than or equal to 200°C, preferably higher than or equal to 60°C and lower than or equal to 150°C, more preferably higher than or equal to 70°C and lower than or equal to 130°C. The heating atmosphere can be an air atmosphere or an inert gas atmosphere. Furthermore, the heating atmosphere can be an atmospheric pressure atmosphere or a reduced pressure atmosphere. Thus, the adhesiveness between the insulating layer 127 and the inorganic insulating layer 125 can be increased, and the corrosion resistance of the insulating layer 127 can also be increased.

[0253] If the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are not completely removed by the first etching treatment, and the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B remain with reduced film thicknesses, the first layer 135R, the first layer 135G, and the first layer 135B can be prevented from being damaged and deteriorated during the heat treatment. Therefore, the reliability of the light-emitting device can be increased.

[0254] Then, as in Fig. 9A, an etching treatment is performed using the insulating layer 127 as a mask, so that the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are partially removed. Thus, openings are formed in the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, and the top surfaces of the first layer 135R, the first layer 135G, the first layer 135B, and the conductive layer 152C are exposed. Note that this etching treatment may be referred to as a second etching treatment hereinafter.

[0255] An end portion of the inorganic insulating layer 125 is covered with the insulating layer 127. Fig. 9A illustrates an example in which a part of an end portion of the sacrificial layer 158G (specifically, a tapered portion formed by the first etching treatment) is covered with the insulating layer 127, and a tapered portion formed by the second etching treatment is exposed.

[0256] The second etching treatment is performed by wet etching. By using a wet etching process, damage to the first layer 135R, the first layer 135G, and the first layer 135B can be reduced more than by using a dry etching process. Wet etching can be performed using, for example, an alkaline solution or an acid solution. An aqueous solution is preferably used to prevent the first layer 135 from dissolving.

[0257] Next, as in Fig. 9B, the second electrode 102 is formed over the first layer 135R, the first layer 135G, the first layer 135B, the conductive layer 152C, and the insulating layer 127. The second electrode 102 may be formed by a sputtering method, a vacuum evaporation method, or the like. In this case, the first layer 135 may have a multilayer structure of the first layer 135 and the common layer 136, as shown in Fig. 3, and the second electrode 102 may be formed thereover.

[0258] Next, as in Fig. As shown in Figure 9C, the protective layer 131 is formed over the second electrode 102. The protective layer 131 can be formed by a vacuum evaporation method, a sputtering method, a CVD method, an ALD method, or the like.

[0259] Subsequently, the substrate 120 is fixed over the protective layer 131 using the resin layer 122; thus, the display device can be manufactured. As described above, in the manufacturing method of the display device of one embodiment of the present invention, the insulating layer 156 is formed to include a region overlapping the side surface of the conductive layer 151, and the conductive layer 152 is formed to cover the conductive layer 151 and the insulating layer 156. This can increase the yield of the display device and prevent the generation of defects.

[0260] As described above, in the manufacturing method of the display device of one embodiment of the present invention, the island-shaped first layer 135R, the island-shaped first layer 135G, and the first layer 135B are formed not by using a fine metal mask but by processing after forming a film on the entire surface, so that the island-shaped layer can be formed with a uniform thickness. Consequently, the display device with high image sharpness or the display device with a high aperture ratio can be achieved. Furthermore, even when the image sharpness or the aperture ratio is high and the distance between subpixels is very short, the first layer 135R, the first layer 135G, and the first layer 135B in adjacent subpixels can be prevented from being in contact with each other. Consequently, generation of a leakage current between the subpixels can be prevented.Thus, crosstalk can be prevented, allowing a display device with very high contrast to be achieved. Furthermore, even a display device comprising tandem light-emitting devices formed by a photolithography process can exhibit advantageous properties. (Embodiment 4)

[0261] In this embodiment, a display device of an embodiment of the present invention will be described.

[0262] The display device of this embodiment can be a high-definition display device. Therefore, the display device of this embodiment can be used for display sections of information terminals (wearable devices), such as wristwatch- or bracelet-type information terminals, and display sections of head-mounted wearable devices, such as a VR device such as a head-mounted display, and a glasses-type AR device.

[0263] The display device of this embodiment can be a high-resolution display device or a large-scale display device. Accordingly, the display device of this embodiment can be used for display sections of a digital camera, a digital video camera, a digital photo frame, a mobile phone, a portable game console, a portable information terminal, and an audio playback device, in addition to an electronic device with a relatively large screen such as a television, a desktop or laptop PC, a computer monitor, and the like, a digital signage device, and a large-scale gaming machine and the like such as a pinball machine. [Display module]

[0264] Fig. 10A is a perspective view of a display module 280. The display module 280 includes a display device 100A and an FPC 290. Note that the display device of the display module 280 is not limited to the display device 100A and may be one of the display devices 100B and 100E described below.

[0265] The display module 280 includes a substrate 291 and a substrate 292. The display module 280 includes a display section 281. The display section 281 is a region of the display module 280 in which an image is displayed, and is a region in which light emitted from respective pixels provided in a pixel section 284 described below can be seen.

[0266] Fig. 10B is a perspective view schematically illustrating a structure on the side of the substrate 291. A circuit portion 282, a pixel circuit portion 283 above the circuit portion 282, and a pixel portion 284 above the pixel circuit portion 283 are stacked one above the other on the substrate 291. Furthermore, a terminal portion 285 for connection to the FPC 290 is provided in a portion that does not overlap with the pixel portion 284 above the substrate 291. The terminal portion 285 and the circuit portion 282 are electrically connected to each other via a wiring portion 286 formed from a plurality of wires.

[0267] The pixel section 284 includes a plurality of pixels 284a arranged periodically. An enlarged view of a pixel 284a is shown on the right side of Fig. 10B. Any of the structures described in the previous embodiments may be applied to pixels 284a. Fig. Figure 10B illustrates an example in which pixel 284a has a structure similar to that of the pixel shown in Fig. 3 is similar to pixel 178.

[0268] The pixel circuit section 283 includes a plurality of pixel circuits 283a arranged periodically.

[0269] A pixel circuit 283a is a circuit that controls the operation of a plurality of elements included in a pixel 284a.

[0270] The circuit section 282 includes a circuit for driving each pixel circuit 283a in the pixel circuit section 283. For example, a gate line driver circuit and / or a source line driver circuit are preferably included. In addition, at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like may be included.

[0271] The FPC 290 serves as a line for supplying a video signal or a power supply potential and the like from the outside to the circuit section 282. An IC can be mounted on the FPC 290.

[0272] The display module 280 may have a structure in which the pixel circuit portion 283 and / or the circuit portion 282 are arranged below the pixel portion 284; therefore, the aperture ratio (the effective display area ratio) of the display portion 281 can be greatly increased.

[0273] Such a display module 280 has very high image sharpness and can therefore be suitably used for a VR device such as an HMD or a glasses-type AR device. For example, even in the case of a structure in which the display portion of the display module 280 is viewed through a lens, since the display module 280 includes the display portion 281 with very high image sharpness, the pixels are not perceived even when the display portion is magnified by the lens, so that a display providing a high sense of immersion can be performed. The display module 280 is not limited to this and can be suitably used for electronic devices including a relatively small display portion. [Display device 100A]

[0274] The Fig. The display device 100A shown in Fig. 11A includes a substrate 301, the light-emitting device 130R, the light-emitting device 130G and the light-emitting device 130B, a capacitor 240, and a transistor 310.

[0275] The substrate 301 corresponds to the substrate 291 in Fig. 10A and Fig. 10B. The transistor 310 is a transistor including the channel formation region in the substrate 301. For the substrate 301, for example, a semiconductor substrate such as a single-crystal silicon substrate can be used. 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 serves as a gate electrode. The insulating layer 313 is disposed between the substrate 301 and the conductive layer 311 and serves as a gate insulating layer. The low-resistance region 312 is a region where the substrate 301 is doped with impurities and serves as a source or drain. The insulating layer 314 is provided to cover the side surface of the conductive layer 311.

[0276] An element isolation layer 315 is provided between two adjacent transistors 310 such that it is embedded in the substrate 301.

[0277] Furthermore, an insulating layer 261 is provided so as to cover the transistor 310, and the capacitor 240 is provided over the insulating layer 261.

[0278] The capacitor 240 includes a conductive layer 241, a conductive layer 245, and an insulating layer 243 therebetween. The conductive layer 241 serves as one electrode of the capacitor 240, the conductive layer 245 serves as the other electrode of the capacitor 240, and the insulating layer 243 serves as the dielectric of the capacitor 240.

[0279] The conductive layer 241 is provided over the insulating layer 261 and is embedded in an insulating layer 254. The conductive layer 241 is electrically connected to a source and drain terminal of the transistor 310 via a terminal plug 271 embedded 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 the conductive layer 241, with the insulating layer 243 interposed therebetween.

[0280] An insulating layer 255 is provided to cover the capacitor 240, the insulating layer 174 is provided over the insulating layer 255, and the insulating layer 175 is provided over the insulating layer 174. The light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B are provided over the insulating layer 175. An insulator is provided in regions between adjacent light-emitting devices.

[0281] The insulating layer 156R is provided to include a region overlapping the side surface of the conductive layer 151R. The insulating layer 156G is provided to include a region overlapping the side surface of the conductive layer 151G. The insulating layer 156B is provided to include a region overlapping the side surface of the conductive layer 151B. The conductive layer 152R is provided to cover the conductive layer 151R and the insulating layer 156R. The conductive layer 152G is provided to cover the conductive layer 151G and the insulating layer 156G. The conductive layer 152B is provided to cover the conductive layer 151B and the insulating layer 156B. The sacrificial layer 158R is positioned over the organic interconnect layer 103R. The sacrificial layer 158R is positioned above the first layer 135R.The sacrificial layer 158G is positioned over the first layer 135G. The sacrificial layer 158B is positioned over the first layer 135B.

[0282] The conductive layer 151R, the conductive layer 151G, and the conductive layer 151B are each electrically connected to a source and drain terminal of the transistor 310 via a terminal plug 256 embedded in the insulating layer 243, the insulating layer 255, the insulating layer 174, and the insulating layer 175, the conductive layer 241 embedded in the insulating layer 254, and the terminal plug 271 embedded in the insulating layer 261. Various conductive materials can be used for the terminal plugs.

[0283] The protective layer 131 is provided over the light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B. The substrate 120 is fixed with the resin layer 122 over the protective layer 131. For details of the components from the light-emitting devices 130 to the substrate 120, reference can be made to Embodiment 3. The substrate 120 corresponds to the substrate 292 in Fig. 10A.

[0284] Fig. 11B shows a variation example of the Fig. 11A. The display device 100A shown in Fig. 11B comprises a color layer 132R, a color layer 132G, and a color layer 132B, and each of the light-emitting devices 130 comprises a region overlapping with one of the color layer 132R, the color layer 132G, and the color layer 132B. In the Fig. For example, in the display device shown in Figure 11B, the light-emitting device 130 may emit white light. For example, the color layer 132R may transmit red light, the color layer 132G may transmit green light, and the color layer 132B may transmit blue light. [Display device 100B]

[0285] Fig. 12 is a perspective view of a display device 100B and Fig. 13 is a cross-sectional view of the display device 100B.

[0286] The display device 100B has a structure in which a substrate 352 and a substrate 351 are attached to each other. In Fig. 12, the substrate 352 is represented by a dashed line.

[0287] The display device 100B includes the pixel portion 177, the connection portion 140, a circuit 356, a wiring 355, and the like. Fig. 12 illustrates an example in which the display device 100B is provided with an IC 354 and an FPC 353. Therefore, the Fig. The structure shown in Figure 12 can be regarded as a display module in which the display device 100B, the IC (integrated circuit), and the FPC are incorporated. Here, a display device in which a substrate is provided with a terminal such as an FPC or mounted with an IC is referred to as a display module.

[0288] The connecting portion 140 is provided outside the pixel portion 177. The number of connecting portions 140 may be one or more. The common electrode of the light-emitting device is electrically connected to a conductive layer in the connecting portion 140, and therefore, a potential can be supplied to the common electrode.

[0289] For example, a scan line driver circuit can be used as circuit 356.

[0290] The line 355 has a function of supplying a signal and a current to the pixel section 177 and the circuit 356. The signal and current are input to the line 355 from the outside via the FPC 353 or from the IC 354.

[0291] Fig. 12 illustrates an example in which the IC 354 is provided over the substrate 351 by a chip-on-glass (COG) method, a chip-on-film (COF) method, or the like. For example, an IC including a scan line driver circuit, a signal line driver circuit, or the like can be used as the IC 354. Note that the display device 100B or the display module does not necessarily have to be provided with an IC. The IC can be mounted on the FPC, for example, by a COF method.

[0292] Fig. 13 shows an example of a cross section of a part of a region including the FPC 353, a part of the circuit 356, a part of the pixel portion 177, a part of the connection portion 140, and a part of a region including an end portion of the display device 100B. [Display device 100C]

[0293] The Fig. The display device 100C shown in Fig. 13 includes the transistor 201, the transistor 205, the light-emitting device 130R that emits red light, the light-emitting device 130G that emits green light, the light-emitting device 130B, and the like between the substrate 351 and the substrate 352.

[0294] For the details of the light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B, reference may be made to Embodiment 1.

[0295] Light-emitting device 130R includes conductive layer 224R, conductive layer 151R over conductive layer 224R, and conductive layer 152R over conductive layer 151R. Light-emitting device 130G includes conductive layer 224G, conductive layer 151G over conductive layer 224G, and conductive layer 152G over conductive layer 151G. Light-emitting device 130B includes conductive layer 224B, conductive layer 151B over conductive layer 224B, and conductive layer 152B over conductive layer 151B.

[0296] The conductive layer 224R is connected to a conductive layer 222b included in the transistor 205 via an opening provided in the insulating layer 214. An end portion of the conductive layer 151R is located further outward than an end portion of the conductive layer 224R. The insulating layer 156R is provided to include a region in contact with the side surface of the conductive layer 151R, and the conductive layer 152R is provided to cover the conductive layer 151R and the insulating layer 156R.

[0297] The conductive layer 224G, the conductive layer 151G, the conductive layer 152G, and the insulating layer 156G in the light-emitting device 130G, and the conductive layer 224B, the conductive layer 151B, the conductive layer 152B, and the insulating layer 156B in the light-emitting device 130B will not be described in detail because they are similar to the conductive layer 224R, the conductive layer 151R, the conductive layer 152R, and the insulating layer 156R in the light-emitting device 130R.

[0298] Recessed portions are formed in the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B to cover the openings in the insulating layer 214. A layer 128 is embedded in the recessed portions.

[0299] Layer 128 has a function of planarizing the recessed portions in conductive layer 224R, conductive layer 224G, and conductive layer 224B. Provided above conductive layer 224R, conductive layer 224G, and conductive layer 224B, as well as layer 128, are conductive layer 151R, conductive layer 151G, and conductive layer 151B, which are electrically connected to conductive layer 224R, conductive layer 224G, and conductive layer 224B. Therefore, regions overlapping with the recessed portions in conductive layer 224R, conductive layer 224G, and conductive layer 224B can also be used as light-emitting regions, thereby increasing the aperture ratio of pixels.

[0300] Layer 128 may be an insulating layer or a conductive layer. Any of various inorganic insulating materials, organic insulating materials, and conductive materials may be appropriately used for layer 128. In particular, layer 128 is preferably formed using an insulating material, and in particular, it is preferably formed using an organic insulating material. For example, an organic insulating material that can be used for insulating layer 127 may be used for layer 128.

[0301] The protective layer 131 is provided over the light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B. The protective layer 131 and the substrate 352 are attached to each other with an adhesive layer 142. The substrate 352 is provided with an opaque layer 157. A solid sealing structure, a hollow sealing structure, or the like can be used to seal the light-emitting devices 130. Fig. 13, a solid sealing structure is used in which a space between the substrate 352 and the substrate 351 is filled with the adhesive layer 142. Alternatively, the space may be filled with an inert gas (e.g., nitrogen or argon), meaning that a hollow sealing structure may be used. In this case, the adhesive layer 142 may be provided such that it does not overlap with the light-emitting devices. Alternatively, the space may be filled with a resin different from that of the frame-shaped adhesive layer 142.

[0302] Fig. 13 illustrates an example in which the connecting portion 140 includes a conductive layer 224C obtained by processing the same conductive film as the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B, the conductive layer 151C obtained by processing the same conductive film as the conductive layer 151R, the conductive layer 151G, and the conductive layer 151B, and the conductive layer 152C obtained by processing the same conductive film as the conductive layer 152R, the conductive layer 152G, and the conductive layer 152B. Fig. In the example shown in Fig. 13, the insulating layer 156C is provided to include a region overlapping with the side surface of the conductive layer 151C.

[0303] The display device 100B has a top-emission structure. Light from the light-emitting devices is emitted toward the substrate 352. A material with high transmittance to visible light is preferably used for the substrate 352. In the case where the light-emitting element emits infrared or near-infrared light, a material with high transmittance to infrared or near-infrared light is preferably used. The first electrode (pixel electrode) includes a visible-light reflective material, and the counter electrode (the second electrode 102) includes a visible-light transmitting material.

[0304] Above the substrate 351, an insulating layer 211, an insulating layer 213, an insulating layer 215, and the insulating layer 214 are provided in this order. A part of the insulating layer 211 serves as the gate insulating layer of each transistor. A part of the insulating layer 213 serves as the gate insulating layer of each transistor. The insulating layer 215 is provided to cover the transistors. The insulating layer 214 is provided to cover the transistors and serves as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited and may be one, two, or more.

[0305] For the insulating layer 211, the insulating layer 213 and the insulating layer 215, an inorganic insulating film is preferably used.

[0306] An organic insulating layer is suitable for the insulating layer 214, which serves as a planarization layer.

[0307] The transistor 201 and the transistors 205 each include a conductive layer 221 serving as a gate, the insulating layer 211 serving as a gate insulating layer, a conductive layer 222a and a conductive layer 222b serving as a source and drain, a semiconductor layer 231, the insulating layer 213 serving as a gate insulating layer, and a conductive layer 223 serving as a gate.

[0308] A connecting portion 204 is provided in a region of the substrate 351 that does not overlap with the substrate 352. In the connecting portion 204, the lead 355 is electrically connected to the FPC 353 via the conductive layer 166 and a connecting layer 242. An example is shown in which the conductive layer 166 has a multi-layer structure of a conductive film obtained by processing the same conductive film as the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B, a conductive film obtained by processing the same conductive film as the conductive layer 151R, the conductive layer 151G, and the conductive layer 151B, and a conductive film obtained by processing the same conductive film as the conductive layer 152R, the conductive layer 152G, and the conductive layer 152B.The conductive layer 166 is exposed on a top surface of the connecting portion 204. Thus, the connecting portion 204 and the FPC 353 can be electrically connected to each other via the connecting layer 242.

[0309] The opaque layer 157 is preferably provided on a surface of the substrate 352 facing the substrate 351. The opaque layer 157 can be provided between adjacent light-emitting devices, in the connecting portion 140, and the circuit 356. Various optical components can be arranged on the outside of the substrate 352.

[0310] A material usable for the substrate 120 can be used for the substrate 351 and the substrate 352, respectively.

[0311] A material usable for the resin layer 122 can be used for the adhesive layer 142.

[0312] For the connection layer 242, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like may be used. [Display device 100D]

[0313] One in Fig. The display device 100D shown in Figure 14 differs from the one shown in Fig. 13 is mainly characterized by the fact that it has a bottom emission structure.

[0314] Light from the light-emitting devices is emitted toward the substrate 351. A material with high visible light transmittance is preferably used for the substrate 351. On the other hand, the light transmittance of a material used for the substrate 352 is not limited.

[0315] An opaque layer 1117 is preferably formed between the substrate 351 and the transistor 201 and between the substrate 351 and the transistor 205. Fig. 14 illustrates an example in which the opaque layer 1117 is provided over the substrate 351, an insulating layer 153 is provided over the opaque layer 1117, and the transistors 201 and 205 and the like are provided over the insulating layer 153.

[0316] The light-emitting device 130R includes a conductive layer 112R, a conductive layer 126R over the conductive layer 112R, and a conductive layer 129R over the conductive layer 126R.

[0317] The light-emitting device 130B includes a conductive layer 112B, a conductive layer 126B over the conductive layer 112B, and a conductive layer 129B over the conductive layer 126B.

[0318] A material with high visible light transmittance is used for each of the conductive layer 112R, the conductive layer 112B, the conductive layer 126R, the conductive layer 126B, the conductive layer 129R, and the conductive layer 129B. A visible light-reflecting material is preferably used for the second electrode 102.

[0319] Although in Fig. 14, the light-emitting device 130G is also provided.

[0320] Although Fig. 14 and the like each illustrate an example in which an upper surface of the layer 128 has a flat portion, the shape of the layer 128 is not limited thereto. [Display device 100E]

[0321] The Fig. The display device 100E shown in Figure 15 is a variation example of the Fig. 13 and differs from the display device 100B mainly in that the color layer 132R, the color layer 132G and the color layer 132B are included.

[0322] In the display device 100E, the light-emitting device 130 includes a region overlapping with one of the color layer 132R, the color layer 132G, and the color layer 132B. The color layer 132R, the color layer 132G, and the color layer 132B may be provided on a surface of the substrate 352 on the substrate 351 side. End portions of the color layer 132R, the color layer 132G, and the color layer 132B may overlap with the light-blocking layer 157.

[0323] In the display device 100E, the light-emitting device 130 can emit white light, for example. For example, the color layer 132R can transmit red light, the color layer 132G can transmit green light, and the color layer 132B can transmit blue light. Note that in the display device 100E, the color layer 132R, the color layer 132G, and the color layer 132B can be provided between the protective layer 131 and the adhesive layer 142.

[0324] Although Fig. 13, Fig. 15 and the like each illustrate an example in which the upper surface of the layer 128 has a flat portion, the shape of the layer 128 is not particularly limited.

[0325] This embodiment may be combined with other embodiments or one of the examples as needed. Where multiple structural examples are shown in one embodiment in this description, the structural examples may be combined as needed. (Embodiment 5)

[0326] In this embodiment, electronic devices of an embodiment of the present invention will be described.

[0327] Electronic devices of this embodiment each include the display device of one embodiment of the present invention in the display section. The display device of one embodiment of the present invention has high display performance, and the display device of one embodiment of the present invention can easily increase image sharpness and resolution. Therefore, the display device of one embodiment of the present invention can be used for display sections of various electronic devices.

[0328] As examples of the electronic device, in addition to electronic devices with a relatively large screen such as a television, a desktop or laptop PC, a monitor of a computer or the like, a digital signage and a large gaming machine such as a pinball machine, a digital camera, a digital video camera, a digital photo frame, a mobile phone, a portable game console, a portable information terminal and an audio playback device are given.

[0329] In particular, the image sharpness of the display device of one embodiment of the present invention can be increased, so the display device of one embodiment of the present invention can be suitably used for an electronic device with a relatively small display section. As such electronic devices, for example, information terminals in the form of a wristwatch and a bracelet (wearable devices) and head-mounted wearable devices such as a device for VR, a head-mounted display, a glasses-like device for AR, and a device for MR are given.

[0330] The electronic device of this embodiment may include a sensor (a sensor having a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electric power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0331] Based on Fig. 16A to Fig. 16D, examples of wearable head-mounted devices are described.

[0332] An electronic device 700A in Fig. 16A and an electronic device 700B in Fig. 16B each include a pair of display panels 751, a pair of housings 721, a communication section (not shown), a pair of fixing sections 723, a control section (not shown), an imaging section (not shown), a pair of optical components 753, a frame 757, and a pair of nose pads 758.

[0333] The display device of one embodiment of the present invention can be used for the display panel 751. Therefore, a highly reliable electronic device can be obtained.

[0334] The electronic device 700A and the electronic device 700B can each project images displayed on the display panel 751 onto display areas 756 of the optical components 753. Since the optical components 753 have light transmission, the user can see images displayed on the display areas superimposed on transmission images viewed through the optical components 753.

[0335] In the electronic device 700A and the electronic device 700B, a front-facing camera may be provided as an imaging section. Furthermore, in the electronic device 700A and the electronic device 700B, the orientation of the user's head may be detected by providing an acceleration sensor such as a gyroscope sensor, and an image may be displayed on the display areas 756 according to the orientation.

[0336] The communication section includes a contactless communication device, and, for example, a video signal can be supplied from the contactless communication device. Note that instead of the wireless communication device or in addition to the wireless communication device, a connector can be provided that can be connected to a cable through which a video signal and a power supply potential are supplied.

[0337] The electronic device 700A and the electronic device 700B are provided with a battery so that they can be charged wirelessly and / or wired.

[0338] A touch sensor module may be provided in the housing 721.

[0339] Various touch sensors can be used on the touch sensor module. For example, one of the following types of touch sensors can be applied: a capacitive type, a resistive type, an infrared type, an electromagnetic induction type, a surface acoustic wave type, and an optical type. In particular, a capacitive sensor or an optical sensor is preferably applied to the touch sensor module.

[0340] An electronic device 800A in Fig. 16C and an electronic device 800B in Fig. 16D each include a pair of display sections 820, a housing 821, a communication section 822, a pair of fixing sections 823, a control section 824, a pair of imaging sections 825, and a pair of lenses 832.

[0341] The display device of one embodiment of the present invention can be used for the display sections 820. Therefore, a highly reliable electronic device can be obtained.

[0342] The display sections 820 are provided within the housing 821 such that they can be viewed through the lenses 832. When different images are displayed on the pair of display sections 820, a three-dimensional display can be performed using parallax.

[0343] The electronic device 800A and the electronic device 800B each preferably include a mechanism for adjusting the lateral positions of the lenses 832 and the display portions 820 so that the lenses 832 and the display portions 820 are optimally located according to positions of the user's eyes.

[0344] The electronic device 800A or the electronic device 800B can be attached to the user's head with the attachment portions 823.

[0345] The imaging section 825 has a function for obtaining information about the external environment. Data obtained by the imaging section 825 can be output to the display section 820. An image sensor can be used for the imaging section 825. Furthermore, multiple cameras can be provided to include multiple fields of view, such as a telescopic field of view and a wide-angle field of view.

[0346] The electronic device 800A may include a vibration mechanism serving as a bone conduction earphone.

[0347] Electronic device 800A and electronic device 800B may each include an input port. A cable may be connected to the input port, through which a video signal from a video output device or the like, as well as power or the like for charging a battery provided in the electronic device, are supplied.

[0348] The electronic device of one embodiment of the present invention may have a function for performing wireless communication with earphones 750.

[0349] The electronic device may include an earphone portion. The electronic device 700B in Fig. 16B includes earphone portions 727. A portion of a line connecting the earphone portions 727 and the control portion may be disposed within the housing 721 or the mounting portion 723.

[0350] Similarly, the electronic device 800B in Fig. 16D earphone sections 827. For example, the earphone sections 827 and the control section 824 may be connected to each other via a line.

[0351] In this way, electronic devices of one embodiment of the present invention are suitable for both eyeglass-type electronic devices (the electronic device 700A, the electronic device 700B, and the like) and goggle-type electronic devices (the electronic device 800A, the electronic device 800B, and the like).

[0352] An electronic device 6500 in Fig. 17A is a portable information terminal that can be used as a smartphone.

[0353] The electronic device 6500 includes a housing 6501, a display section 6502, a power button 6503, buttons 6504, a speaker 6505, a microphone 6506, a camera 6507, a light source 6508, and the like. The display section 6502 has a touchscreen function.

[0354] The display device of one embodiment of the present invention can be used for the display section 6502. Therefore, a highly reliable electronic device can be obtained.

[0355] Fig. 17B is a schematic cross-sectional view including an end portion of the housing 6501 on the side of the microphone 6506.

[0356] A protective component 6510 having light transmittance is provided over a display surface side of the housing 6501, and a display panel 6511, an optical component 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, and the like are arranged in a space enclosed by the housing 6501 and the protective component 6510.

[0357] The display panel 6511, the optical component 6512 and the touch sensor panel 6513 are attached to the protective component 6510 with an adhesive layer (not shown).

[0358] In an area outside the display section 6502, the display panel 6511 is partially folded back, and an FPC 6515 is connected to the folded back portion. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on the printed circuit board 6517.

[0359] A flexible display panel of one embodiment of the present invention can be used as the display panel 6511. Therefore, a very lightweight electronic device can be achieved. Since the thickness of the display panel 6511 is very small, the high-capacity battery 6518 can be mounted while controlling the thickness of the electronic device. An electronic device with a narrow frame can be achieved if the display panel 6511 is partially folded back so that the portion connected to the FPC 6515 is disposed on the back side of a pixel portion.

[0360] Fig. 17C illustrates an example of a television set. In a television set 7100, a display section 7000 is installed in a case 7171. Here, a structure is shown in which the case 7171 is supported by a stand 7173.

[0361] The display device of one embodiment of the present invention can be used for the display section 7000. Therefore, a highly reliable electronic device can be obtained.

[0362] The 7100 television in Fig. 17C can be operated with a control switch in the housing 7171 and a separate remote control 7151.

[0363] Fig. 17D illustrates an example of a laptop PC. The laptop PC 7200 includes a case 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. The display section 7000 is installed in the case 7211.

[0364] The display device of one embodiment of the present invention can be used for the display section 7000. Therefore, a highly reliable electronic device can be obtained.

[0365] Fig. 17E and Fig. 17F each represent an example of digital signage.

[0366] A Digital Signage 7300 in Fig. 17E includes a housing 7301, the display section 7000, a speaker 7303, and the like. The digital signage 7300 may also include an LED lamp, control buttons (including a power button or a control switch), a connection port, various sensors, a microphone, and the like.

[0367] Fig. 17F is a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 includes the display section 7000 provided along a curved surface of the column 7401.

[0368] The display device of an embodiment of the present invention can be used for the display section 7000 in Fig. 17E and Fig. 17F can be used. Therefore, a very reliable electronic device can be obtained.

[0369] A larger area of ​​the display section 7000 can increase the amount of data that can be provided at once. The larger display section 7000 attracts more attention, so that, for example, the effectiveness of advertising can be increased.

[0370] In addition, it is preferred that, as in Fig. 17E and Fig. 17F, the digital signage 7300 or the digital signage 7400 can interact with an information terminal 7311 or an information terminal 7411, such as a smartphone, possessed by a user through wireless communication.

[0371] In Fig. 18A to Fig. 18G each includes a housing 9000, a display section 9001, a speaker 9003, an operation button 9005 (including a power button or an operation switch), a connection terminal 9006, a sensor 9007 (a sensor having a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electric power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), a microphone 9008, and the like.

[0372] The electronic devices in Fig. 18A to Fig. 18G have various functions. For example, the electronic devices may have a function for displaying various information (a still image, a moving image, a text image, and the like) on the display section, a touchscreen function, a function for displaying a calendar, the date, time, and the like, a processing control function with various types of software (programs), a wireless communication function, and a function for reading and processing a program or data stored in a storage medium.

[0373] The electronic devices in Fig. 18A to Fig. 18G are described in detail below.

[0374] Fig. 18A is a perspective view of a portable information terminal 9171. The portable information terminal 9171 can be used, for example, as a smartphone. Note that the portable information terminal 9171 may include the speaker 9003, the connection terminal 9006, the sensor 9007, or the like. The portable information terminal 9171 can display characters and image information on its plurality of surfaces. Fig. 18A illustrates an example in which three icons 9050 are displayed. In addition, information 9051 represented by dashed rectangles may be displayed on another surface of the display section 9001. Examples of the information 9051 include a notification of the arrival of an email, an SNS message, a call, or the like; the subject and sender of an email, an SNS message, or the like; the date, time, remaining battery power, and the intensity of a radio wave. The icon 9050 or the like may alternatively be displayed in the position where the information 9051 is displayed.

[0375] Fig. 18B is a perspective view of a portable information terminal 9172. The portable information terminal 9172 has a function of displaying information on three or more surfaces of the display section 9001. Here, for example, information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, the user can check the information 9053 displayed in such a way that it can be viewed from above the portable information terminal 9172 with the portable information terminal 9172 stored in a breast pocket of their clothing.

[0376] Fig. 18C is a perspective view of a tablet terminal 9173. The tablet terminal 9173 is suitable for executing various applications, such as mobile phone calls, sending and receiving emails, viewing and editing texts, playing music, Internet communication, and playing computer games. The tablet terminal 9173 includes the display section 9001, the camera 9002, the microphone 9008, and the speaker 9003 on a front side of the housing 9000; the operation buttons 9005 as buttons for operation on a left side surface of the housing 9000; and the connection port 9006 on a bottom side of the housing 9000.

[0377] Fig. 18D is a perspective view of a wearable information terminal 9200 in the form of a wristwatch. The wearable information terminal 9200 can be used, for example, as a smartwatch (registered trademark). Furthermore, the display surface of the display section 9001 is curved, and display can be performed along the curved display surface. In the wearable information terminal 9200, for example, mutual communication with a headset capable of wireless communication enables hands-free phone calls. The connection port 9006 enables the wearable information terminal 9200 to perform mutual data transmission with another information terminal and charging. Note that charging can be performed by wireless power supply.

[0378] Fig. 18E to Fig. 18G are perspective views of a foldable portable information terminal 9201. Fig. 18E is a perspective view of a state in which the portable information terminal 9201 is unfolded, Fig. Fig. 18G is a perspective view of a state in which the portable information terminal 9201 is folded, and Fig. 18F is a perspective view when switching between the state in Fig. 18E and the condition in Fig. 18G. The portable information terminal 9201 is highly portable in the folded state and highly searchable in the unfolded state due to a seamless large display area. The display section 9001 of the portable information terminal 9201 is supported by three housings 9000 connected to each other by hinges 9055. For example, the display section 9001 can be bent with a radius of curvature greater than or equal to 0.1 mm and less than or equal to 150 mm.

[0379] This embodiment may be combined with other embodiments or one of the examples as needed. Where multiple structural examples are shown in one embodiment in this description, the structural examples may be combined as needed. [Example]

[0380] In this example, the light-emitting device of one embodiment of the present invention and a comparative light-emitting device are described. Note that in some cases, light-emitting devices are collectively referred to by different suffix numbers in this specification. For example, a light-emitting device 1-1 and a light-emitting device 1-2 are collectively referred to as light-emitting device 1. [Light-emitting devices 1 to 4]

[0381] The manufacturing methods and properties of light-emitting devices 1 to 4 of one embodiment of the present invention that emit green phosphorescent light are described in detail below. Structural formulas of the main compounds used in the light-emitting devices 1 to 4 are shown below. (Manufacturing method of the light-emitting device 1-1)

[0382] First, 100 nm thick silver (Ag) as a reflective electrode and then 85 nm thick indium tin oxide containing silicon oxide (ITSO) as a transparent electrode were sequentially deposited on a glass substrate by sputtering from the substrate side, thereby forming the first electrode 101 with a size of 2 mm × 2 mm. Note that ITSO serves as an anode and, together with the above Ag multilayer structure, is considered the first electrode 101.

[0383] Then, a pretreatment for forming the light-emitting device over the substrate was performed by washing the substrate surface with water.

[0384] The substrate was then transferred to a vacuum evaporation device where the pressure was increased to approximately 1 × 10 -4Pa, and vacuum baking was performed at 170°C for 30 minutes in a heating chamber of the vacuum evaporation device, and then the substrate was cooled for approximately 30 minutes.

[0385] Then, the substrate was attached to a holder provided in a vacuum evaporation device such that the surface on which the first electrode 101 is formed faced downward; over an inorganic insulating film and the first electrode 101, N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and a fluorine-containing electron acceptor material with a molecular weight of 672 (OCHD-003) were co-evaporated to a thickness of 10 nm such that the weight ratio of PCBBiF:OCHD-003 was 1:0.03, thereby forming the hole injection layer 111.

[0386] PCBBiF was deposited by evaporation over the hole injection layer 111 to a thickness of 70 nm, forming the hole transport layer 112.

[0387] Subsequently, 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), represented by the above structural formula (ii), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP), represented by the above structural formula (iii), and [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)) represented by the structural formula (iv) was deposited by co-evaporation to a thickness of 40 nm such that the weight ratio of BP-Icz(II)Tzn: βNCCP: Ir(5mppy-d3)2(mbfpypy-d3) was 0.5:0.5:0.1, thereby forming the light-emitting layer 113.

[0388] Next, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), represented by the above structural formula (v), was deposited by evaporation to a thickness of 20 nm to form a first electron-transport layer, and then 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), represented by the structural formula (vi), was deposited by evaporation to a thickness of 15 nm to form a second electron-transport layer, thereby forming the electron-transport layer 114. Note that the first electron-transport layer also serves as a hole-blocking layer.

[0389] Thereafter, a one-hour standing in the air atmosphere under light shielding was carried out, followed by a one-hour heat treatment at 110 °C in an atmosphere of approximately 1 × 10 -4 Pa or lower.

[0390] After the heat treatment, lithium fluoride (LiF) and ytterbium (Yb) were co-evaporated to a thickness of 1.5 nm such that the volume ratio of LiF:Yb was 1:0.5 to form the electron injection layer 115. Thereafter, silver (Ag) and magnesium (Mg) were co-evaporated to a thickness of 15 nm such that the volume ratio of Ag:Mg was 1:0.1, thereby forming the second electrode 102. Over the second electrode 102, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), represented by the above structural formula (v), was deposited to a thickness of 70 nm as a cap layer to improve the light extraction efficiency.

[0391] Subsequently, the light-emitting device was sealed using a glass substrate in a glove box containing a nitrogen atmosphere so that it was not exposed to the air (a UV-curing sealing material was applied to enclose the element, only the UV-curing sealing material was irradiated with UV while preventing the light-emitting device from being irradiated with the UV, and a heat treatment was performed under atmospheric pressure at 80 °C for one hour), and the light-emitting device 1-1 was manufactured. (Manufacturing method of the light-emitting device 1-2)

[0392] Light-emitting device 1-2 was manufactured in a similar manner to light-emitting device 1-1, except that after forming the electron-transport layer in light-emitting device 1-1, it was allowed to stand in an air atmosphere under irradiation with a fluorescent lamp. Note that the illuminance of the fluorescent lamp was 317 lux. (Manufacturing method of the light-emitting device 2-1)

[0393] The light-emitting device 2-1 was prepared in a similar manner to the light-emitting device 1-1, except that 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), represented by the above structural formula (viii), was used instead of BP-Icz(II)Tzn in the light-emitting device 1-1. (Manufacturing method of the light-emitting device 2-2)

[0394] Light-emitting device 2-2 was manufactured in a similar manner to light-emitting device 2-1, except that after forming the electron-transport layer in light-emitting device 2-1, it was allowed to stand in an air atmosphere under irradiation with a fluorescent lamp. Note that the illuminance of the fluorescent lamp was 317 lux. (Manufacturing method of the light-emitting device 3-1)

[0395] The light-emitting device 3-1 was prepared in a similar manner to the light-emitting device 1-1, except that 4-{4-[2-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}benzofuro[3,2-d]pyrimidine (abbreviation: 4PCCzPBfpm), represented by the structural formula (ix), was used instead of BP-Icz(II)Tzn in the light-emitting device 1-1. (Manufacturing method of the light-emitting device 3-2)

[0396] Light-emitting device 3-2 was fabricated in a similar manner to light-emitting device 3-1, except that after forming the electron-transport layer in light-emitting device 3-1, it was allowed to stand in an air atmosphere under irradiation with a fluorescent lamp. Note that the illuminance of the fluorescent lamp was 317 lux. (Manufacturing method of the light-emitting device 4-1)

[0397] The light-emitting device 4-1 was prepared in a similar manner to the light-emitting device 1-1, except that 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), represented by the above structural formula (x), was used instead of BP-Icz(II)Tzn in the light-emitting device 1-1. (Manufacturing method of the light-emitting device 4-2)

[0398] Light-emitting device 4-2 was manufactured in a similar manner to light-emitting device 4-1, except that after forming the electron-transport layer in light-emitting device 4-1, it was allowed to stand in an air atmosphere under irradiation with a fluorescent lamp. Note that the illuminance of the fluorescent lamp was 317 lux.

[0399] The device structures of the light-emitting devices 1-1 to 4-2 are shown in the table below. [Table 1] Filmdicke(nm) LichtemittierendeVorrichtung1-X LichtemittierendeVorrichtung2-X LichtemittierendeVorrichtung3-X Light-emitting device 4-X Cap layer i 70 DBT3P-II second electrode 15 Ag:Mg (1:0.1) 1,5 LiF:Yb(2:1) Air exposure *1 second electron transport layer 15 mPPhen2P first electron transport layer 20 2mPCCzPDBq Light-emitting layer 40 *2:βNCCP:lr(5mppy-d3)2(mbfpypy-d3)(0.5:0.5:0.1) Hole transport layer 70 PCBBiF Hole injection layer 10 PCBBiF:OCHD-003(1:0.03) first electrode transparent electrode 85 ITSO reflective electrode 100 Ag *1 X=1: light shielding, X=2: irradiation with the fluorescent lamp *2Light-emitting device 1-X:BP-Icz(II)Tzr Light-emitting device 2-X:mPCCzPTzn-02 Light-emitting device 3-X:4PCCzPBfpm Light-emitting device 4-X:4.6mDBTP2Pm-II

[0400] Fig. 19 to Fig. 22 show absorption spectra of the organic compounds used in the light-emitting layers of the light-emitting devices 1 to 4, an emission spectrum of the fluorescent lamp, and an emission spectrum of orange light, respectively.

[0401] It should be noted that the absorption spectrum of the host material was measured in a thin film state. Specifically, the respective organic compounds were formed as an approximately 50 nm thick thin film over a quartz substrate, and a measurement was performed. The absorption spectrum was measured with a UV-VIS spectrophotometer (U-4100, manufactured by Hitachi, Ltd.). The absorption spectrum of the thin film was calculated using an absorbance (-log 10 (%T / (100-%R))), which was obtained from the transmittance (%T) and reflectance (%R) of the substrate and the thin film.

[0402] The measurement was performed on the light-emitting substance in a solution state. Specifically, the absorption spectrum (UV-VIS absorption spectrum) of Ir(5mppy-d3)2(mbfpypy-d3) was measured in a dichloromethane solution. The absorption spectrum was measured using a UV-VIS spectrophotometer (V550, manufactured by JASCO Corporation).

[0403] Fig. 19 to Fig.22 and the above structural formulas show that the substances other than the light-emitting substance (the host material and the auxiliary material) used in the light-emitting devices 1 to 4 each satisfy the following conditions: the wavelength of the absorption edge having the longest wavelength in the absorption spectrum is shorter than 400 nm; no structure is included in which two adjacent six-membered aromatic rings are condensed, in which two adjacent six-membered heteroaromatic rings are condensed, and in which a six-membered aromatic ring and a six-membered heteroaromatic ring that are adjacent to each other are condensed; the included condensed ring is a condensed ring in which a six-membered ring and a five-membered ring are alternately condensed; no naphthalene skeleton is included;Neither a naphthalene ring nor a phenanthrene ring nor a naphthacene ring is included; and no condensed aromatic ring formed only of six-membered rings is included; accordingly, the light-emitting devices 1 to 4 are each the light-emitting device of one embodiment of the present invention.

[0404] In particular, among the absorption edges in the absorption spectra, the absorption edges with the longest wavelength of βNCCP, BP-Icz(II)Tzn, mPCCzPTzn-02, 4PCCzPBfpm and 4,6mDBTP2Pm-II were located at 372 nm, 398 nm, 375 nm, 448 nm and 355 nm, respectively. Furthermore, the absorbances of βNCCP, BP-Icz(II)Tzn and mPCCzPTzn-02 were less than or equal to 0.01 at a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm, respectively.

[0405] Among the absorption edges in the absorption spectrum of Ir(5mppy-d3)2(mbfpypy-d3), the absorption edge with the longest wavelength was at 526 nm. The molar absorption coefficient of Ir(5mppy-d3)2(mbfpypy-d3) at a wavelength of 400 nm was 11700 M -1 ·cm -1 .

[0406] Fig. 23 to Fig. Figure 26 shows the initial characteristics of these light-emitting devices. Among the drawings, A represents the luminance-current density characteristics, B represents the current efficiency-luminance characteristics, C represents the current density-voltage characteristics, and D represents the electroluminescence spectra. The values ​​of the principal voltage, principal current, principal current density, principal CIE chromaticity, and principal current efficiency at 1000 cd / cm 2are shown below. The luminance, CIE chromaticity, and emission spectra were measured using a spectroradiometer (SR-UL1R, manufactured by TOPCON TECHNOHOUSE CORPORATION) at normal temperature. [Table 2] Voltage (V) Current (mA) Current density (mA / cm 2 ) Chromaticityx Chromaticity Power efficiency (cd / A) Light-emitting device 1-1 2,5 0,02 0,5 0,28 0,69 140,1 Light-emitting device 1-2 2,6 0,04 1,0 0,29 0,69 124,4 Light-emitting device 2-1 2,7 0,02 0,6 0,29 0,68 143,3 Light-emitting device 2-2 2,7 0,02 0,5 0,29 0,69 142,2 Light-emitting device 3-1 2,7 0,03 0,9 0,33 0,65 129,1 Light-emitting device 3-2 2,7 0,03 0,8 0,34 0,65 126,2 Light-emitting device 4-1 3,0 0,03 0,8 0,29 0,69 142,6 Light-emitting device 4-2 3,0 0,03 0,7 0,29 0,68 140,6

[0407] Fig. 23 to Fig. 26 show that in the light-emitting device of one embodiment of the present invention, no difference in operating voltage occurs depending on the presence or absence of fluorescent lamp irradiation when the light-emitting device is exposed to air during manufacture. Also, the current efficiency was not reduced in the light-emitting devices 2 to 4.

[0408] Fig. Figure 27 shows changes in luminance over the operating time when operating with a constant current at a current density of 50 mA / cm 2 . Fig.27 shows that the light-emitting device of one embodiment of the present invention has no difference in the change of luminance over the operating time depending on the presence or absence of the irradiation of the fluorescent lamp. [Light-emitting device 5]

[0409] The manufacturing methods and characteristics of light-emitting devices 5 of one embodiment of the present invention that emit blue phosphorescent light will be described in detail below. The organic compounds used in the light-emitting devices 5 are shown below. (Manufacturing Method of Light-Emitting Device 5-1)

[0410] First, 100 nm thick silver (Ag) as a reflective electrode and then 85 nm thick indium tin oxide containing silicon oxide (ITSO) as a transparent electrode were sequentially deposited on a glass substrate by sputtering from the substrate side, thereby forming the first electrode 101 with a size of 2 mm × 2 mm. Note that ITSO serves as an anode and, together with the above Ag multilayer structure, is considered the first electrode 101.

[0411] Then, a pretreatment for forming the light-emitting device over the substrate was performed by washing the substrate surface with water.

[0412] The substrate was then transferred to a vacuum evaporation device where the pressure was increased to approximately 1 × 10 -4Pa, and vacuum baking was performed at 170 °C for 30 minutes in a heating chamber of the vacuum evaporation device, and then the substrate was cooled for approximately 30 minutes.

[0413] Then, the substrate was attached to a holder provided in a vacuum evaporation device such that the surface on which the first electrode 101 is formed faced downward; over an inorganic insulating film and the first electrode 101, N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf) represented by the above structural formula (xi) and a fluorine-containing electron acceptor material with a molecular weight of 672 (OCHD-003) were co-evaporated to a thickness of 10 nm such that the weight ratio of BBABnf:OCHD-003 was 1:0.1, thereby forming the hole injection layer 111.

[0414] Over the hole injection layer 111, BBABnf was deposited by evaporation to a thickness of 40 nm, and then 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP) represented by the above structural formula (xii) was deposited by evaporation to a thickness of 20 nm, thereby forming the hole transport layer 112.

[0415] Subsequently, over the hole transport layer 112, 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), represented by the above structural formula (xiii), PCCP, and tris{2-[4-(4-cyano-2,6-diisobutylphenyl)-5-(2-methylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: Ir(mpptz-diBuCNp)3), represented by the above structural formula (xiv), were co-evaporated to a thickness of 30 nm such that the weight ratio of 4,6mCzP2Pm: PCCP: Ir(mpptz-diBuCNp)3 was 0.5:0.5:0.06 to form the first light-emitting layer, and then 4,6mCzP2Pm, PCCP and Ir(mpptz-diBuCNp)3 were deposited by co-evaporation to a thickness of 10 nm such that the weight ratio of 4,6mCzP2Pm:PCCP:Ir(mpptzdiBuCNp)3 was 0.8:0.2:0.06 to form the second light-emitting layer, thereby forming the light-emitting layer 113.

[0416] Next, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), represented by the above structural formula (v), was deposited by evaporation to a thickness of 10 nm to form the first electron-transport layer, and then 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), represented by the above structural formula (vi), was deposited by evaporation to a thickness of 15 nm to form the second electron-transport layer, thereby forming the electron-transport layer 114. Note that the first electron-transport layer also serves as a hole-blocking layer.

[0417] Thereafter, a one-hour standing in the air atmosphere under light shielding was carried out, followed by a one-hour heat treatment at 110 °C in an atmosphere of approximately 1 × 10 -4 Pa or lower.

[0418] After the heat treatment, lithium fluoride (LiF) and ytterbium (Yb) were co-evaporated to a thickness of 1.5 nm such that the volume ratio of LiF:Yb was 1:0.5 to form the electron injection layer 115. Thereafter, silver (Ag) and magnesium (Mg) were co-evaporated to a thickness of 15 nm such that the volume ratio of Ag:Mg was 1:0.1, thereby forming the second electrode 102. Over the second electrode 102, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), represented by the above structural formula (v), was deposited to a thickness of 70 nm as a cap layer to improve the light extraction efficiency.

[0419] Subsequently, the light-emitting device was sealed using a glass substrate in a glove box containing a nitrogen atmosphere so that it was not exposed to the air (a UV-curing sealing material was applied to enclose the element, only the UV-curing sealing material was irradiated with UV while preventing the light-emitting device from being irradiated with the UV, and a heat treatment was performed under atmospheric pressure at 80 °C for one hour), and the light-emitting device 5-1 was manufactured. (Manufacturing method of the light-emitting device 5-2)

[0420] Light-emitting device 5-2 was manufactured in a similar manner to light-emitting device 5-1, except that after forming the electron-transport layer in light-emitting device 5-1, it was allowed to stand in an air atmosphere under irradiation with a fluorescent lamp. Note that the illuminance of the fluorescent lamp was 317 lux. (Manufacturing method of the light-emitting device 5-3)

[0421] Light-emitting device 5-3 was manufactured in a similar manner to light-emitting device 5-1, except that after forming the electron-transport layer in light-emitting device 5-1, it was allowed to stand in an air atmosphere under irradiation with orange light. Note that the illuminance of orange light was 111 lux.

[0422] The device structures of the light-emitting devices 5-1 to 5-3 are shown in the table below. [Table 3] Film thickness (nm) Light-emitting device 5-1 Light-emitting device5-2 Light-emitting device5-3 Cap layer 70 DBT3P-II second electrode 15 Ag:Mg (1:0.1) 1,5 LiF:Yb (2:1) Air exposure Light shielding Irradiation with the fluorescent lamp Irradiation with orange light Electron transport layer 15 mPPhen2P 10 2mPCCzPDBq Light-emitting layer 10 4.6mCzP2Pm:PCCP:Ir(mpptz-diBuCNp)3(0.8:0.2:0.06) 30 4.6mCzP2Pm:PCCP:Ir(mpptz-diBuCNp)3(0.5:0.5:0.06) Hole transport layer 20 PCCP 40 BBABnf Hole injection layer 10 BBABnf:OCHD-003(1:0.1) first electrode transparent electrode 85 ITSO reflective electrode 100 Ag

[0423] Fig. 28 shows absorption spectra of the organic compounds used in the light-emitting layers of the light-emitting devices 5, the emission spectrum of the fluorescent lamp, and the emission spectrum of orange light.

[0424] It should be noted that the absorption spectrum of the host material was measured in a thin film state. Specifically, the respective organic compounds were formed as an approximately 50 nm thick thin film over a quartz substrate, and a measurement was performed. The absorption spectrum was measured with a UV-VIS spectrophotometer (U-4100, manufactured by Hitachi, Ltd.). The absorption spectrum of the thin film was calculated using an absorbance (-log 10(%T / (100-%R))), which was obtained from the transmittance (%T) and reflectance (%R) of the substrate and the thin film.

[0425] The measurement was performed on the light-emitting substance in a solution state. Specifically, the absorption spectrum (UV-VIS absorption spectrum) of Ir(mpptz-diBuCNp)3 was measured in a dichloromethane solution. The absorption spectrum was measured using a UV-VIS spectrophotometer (V550, manufactured by JASCO Corporation).

[0426] Fig.28 and the above structural formulas show that the substances other than the light-emitting substance (the host material) used in the light-emitting devices 5 satisfy the following conditions: the wavelength of the absorption edge having the longest wavelength in the absorption spectrum is shorter than 400 nm; no structure is included in which two adjacent six-membered aromatic rings are condensed, in which two adjacent six-membered heteroaromatic rings are condensed, and in which a six-membered aromatic ring and a six-membered heteroaromatic ring that are adjacent to each other are condensed; the included condensed ring is a condensed ring in which a six-membered ring and a five-membered ring are alternately condensed; no naphthalene skeleton is included; neither a naphthalene ring nor a phenanthrene ring nor a naphthacene ring is included;and no condensed aromatic ring is included, which is formed only of six-membered rings; accordingly, the light-emitting devices 5 are each the light-emitting device of one embodiment of the present invention.

[0427] In particular, among the absorption edges in the absorption spectra, the absorption edges with the longest wavelength of PCCP and 4.6mCzP2Pm were located at 370 nm and 390 nm, respectively. Furthermore, the absorbances of PCCP and 4.6mCzP2Pm were less than or equal to 0.01 at a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm, respectively.

[0428] Among the absorption edges in the absorption spectrum of Ir(mpptzdiBuCNp)3, the absorption edge with the longest wavelength was located at 478 nm. The molar absorption coefficient of Ir(mpptz-diBuCNp)3 at a wavelength of 400 nm was 5490 M -1 ·cm -1 .

[0429] Fig. 29 shows the luminance-current density characteristics of these light-emitting devices 5, Fig. 30 shows the power efficiency-luminance characteristics of these, Fig. 31 shows the luminance-voltage characteristics of this, Fig. 32 shows the current density-voltage characteristics of this, Fig. 33 shows the blue index luminance characteristics of these and Fig. Figure 34 shows the emission spectra of these. The values ​​of the principal voltage, the principal current, the principal current density, the principal CIE chromaticity, the principal current efficiency, and the principal blue index (BI) at 1000 cd / cm 2 are shown below. The luminance, CIE chromaticity, and emission spectra were measured using a spectroradiometer (SR-UL1R, manufactured by TOPCON TECHNOHOUSE CORPORATION) at normal temperature. [Table 4] Voltage (V) Current (mA) Current density (mA / cm 2 ) Chromaticityx Chromaticity Power efficiency (cd / A) BI(cd / A / y) Light-emitting device 5-1 3,5 0,05 1,2 0,09 0,49 70,7 143 Light-emitting device 5-2 3,6 0,05 1,4 0,10 0,55 75,8 Light-emitting device 5-3 3,5 0,06 1,6 0,09 0,50 68,7 137

[0430] Fig. 29 to Fig. 34 show that in the light-emitting device of one embodiment of the present invention, no difference in operating voltage occurs depending on the presence or absence of irradiation with a fluorescent lamp or orange light when the light-emitting device is exposed to air during manufacture. Also, the power efficiency of the light-emitting devices 5 was not reduced.

[0431] Fig. Figure 35 shows changes in luminance over the operating time when operating with a constant current at a current density of 50 mA / cm 2 . Fig. 35 shows that the light-emitting device of one embodiment of the present invention has no difference in the change of luminance over the operating time depending on the presence or absence of the irradiation of the fluorescent lamp or orange light. [Comparative Light-Emitting Device 1 and Comparative Light-Emitting Device 2]

[0432] The manufacturing methods and characteristics of comparative light-emitting devices 1 and 2, which are comparative examples of light-emitting devices that emit blue fluorescent light, are described in detail below. The organic compounds used in comparative light-emitting devices 1 and 2 are shown below. (Manufacturing method of the comparative light-emitting device 1-0)

[0433] First, 100 nm thick silver (Ag) as a reflective electrode and then 85 nm thick indium tin oxide containing silicon oxide (ITSO) as a transparent electrode were sequentially deposited on a glass substrate by sputtering from the substrate side, thereby forming the first electrode 101 with a size of 2 mm × 2 mm. Note that ITSO serves as an anode and, together with the above Ag multilayer structure, is considered the first electrode 101.

[0434] Then, a pretreatment for forming the light-emitting device over the substrate was performed by washing the substrate surface with water.

[0435] The substrate was then transferred to a vacuum evaporation device where the pressure was increased to approximately 1 × 10 -4Pa, and vacuum baking was performed at 170 °C for 30 minutes in a heating chamber of the vacuum evaporation device, and then the substrate was cooled for approximately 30 minutes.

[0436] Then, the substrate was attached to a holder provided in a vacuum evaporation device such that the surface on which the first electrode 101 is formed faced downward; over an inorganic insulating film and the first electrode 101, N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and a fluorine-containing electron acceptor material with a molecular weight of 672 (OCHD-003) were co-evaporated to a thickness of 10 nm such that the weight ratio of PCBBiF:OCHD-003 was 1:0.04, thereby forming the hole injection layer 111.

[0437] Over the hole injection layer 111, PCBBiF was deposited by evaporation to a thickness of 30 nm, and then N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), represented by the structural formula (xv), was deposited by evaporation to a thickness of 10 nm, thereby forming the hole transport layer 112.

[0438] Subsequently, over the hole transport layer 112, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), represented by the above structural formula (xvi), and 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-O2), represented by the above structural formula (xvii), were co-deposited to a thickness of 20 nm such that the weight ratio of αN-βNPAnth: 3,10PCA2Nbf(IV)-O2 was 1:0.015, thereby forming the light-emitting layer 113. became.

[0439] Next, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), represented by the above structural formula (v), was deposited by evaporation to a thickness of 20 nm to form the first electron-transport layer, and then 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), represented by the above structural formula (xviii), was deposited by evaporation to a thickness of 15 nm to form the second electron-transport layer, thereby forming the electron-transport layer 114. Note that the first electron-transport layer also serves as a hole-blocking layer.

[0440] Next, lithium fluoride (LiF) and ytterbium (Yb) were co-evaporated to a thickness of 2 nm such that the volume ratio of LiF:Yb was 1:1 to form the electron injection layer 115. After that, silver (Ag) and magnesium (Mg) were co-evaporated to a thickness of 15 nm such that the volume ratio of Ag:Mg was 1:0.1, thereby forming the second electrode 102. Over the second electrode 102, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), represented by the above structural formula (v), was deposited to a thickness of 70 nm as a cap layer to improve the light extraction efficiency.

[0441] Subsequently, the light-emitting device was sealed using a glass substrate in a glove box containing a nitrogen atmosphere so that it was not exposed to the air (a UV-curing sealing material was applied to enclose the element, only the UV-curing sealing material was irradiated with UV while preventing the light-emitting device from being irradiated with the UV, and a heat treatment was performed under atmospheric pressure at 80 °C for one hour), and the comparative light-emitting device 1-0 was manufactured. (Manufacturing method of the comparative light-emitting device 1-1)

[0442] The comparative light-emitting device 1-1 was manufactured in a similar manner to the comparative light-emitting device 1-0, except that after the formation of the electron-transport layer in the comparative light-emitting device 1-0, it was left to stand for one hour in the air atmosphere while shielding from light, followed by a heat treatment at 110 °C for one hour in an atmosphere of approximately 1 × 10 -4 Pa or lower, and then the electron injection layer and subsequent components were formed. (Manufacturing method of the comparative light-emitting device 1-2)

[0443] The comparative light-emitting device 1-2 was manufactured in a similar manner to the comparative light-emitting device 1-0, except that after the first hole-transport layer was formed in a thickness of 35 nm in the comparative light-emitting device 1-0 and then the electron-transport layer was formed, a one-hour standing in the air atmosphere under the irradiation of the fluorescent lamp was carried out, followed by a one-hour heat treatment at 110 °C in an atmosphere of approximately 1 × 10 -4 Pa or lower, and then the electron injection layer and subsequent components were formed. Note that the illuminance of the fluorescent lamp was 317 lux.

[0444] The comparative light-emitting device 1-3 was manufactured in a similar manner to the comparative light-emitting device 1-0, except that after the formation of the electron-transport layer in the comparative light-emitting device 1-0, it was allowed to stand for one hour in the air atmosphere under irradiation with orange light, followed by a one-hour heat treatment at 110 °C in an atmosphere of approximately 1 × 10 -4 Pa or lower, and then the electron injection layer and subsequent components were formed. Note that the illuminance of orange light was 111 lux.

[0445] The device structures of the comparative light-emitting devices 1-0 to 1-3 are shown in the table below. [Table 5] Film thickness (nm) Light-emitting comparison device 1-0 Light-emitting comparison device 1-1 Light-emitting comparison device 1-2 Light-emitting comparison device 1-3 Cap layer 70 DBT3P-II second electrode 20 Ag:Mg (1:0.1) 2 LiF:Yb (1:1) Air exposure without (continuous vacuum process) Light shielding Irradiation with the fluorescent lamp Irradiation with orange light Electron transport layer 15 NBPhen 20 2mPCCzPDBq Light-emitting layer 20 aN-βNPAnth:3.10PCA2Nbf(IV)-02(1:0.015) Hole transport layer 10 DBfBB1TP *1 PCBBiF Hole injection layer 10 PCBBiF:OCHD-003(1:0.04) firstElectrode transparent electrode 85 ITSO reflective electrode 100 Ag *1:Comparative light-emitting device 1-0 30 nm Light-emitting comparison device 1-1 30 nm Light-emitting comparison device 1-2 35 nm Light-emitting comparison device 1-3 30 nm

[0446] Fig.36 shows absorption spectra of the organic compounds used in the light-emitting layers of the comparative light-emitting devices 1, the emission spectrum of the fluorescent lamp, and the emission spectrum of orange light.

[0447] It should be noted that the absorption spectrum of the host material was measured in a thin film state. Specifically, the respective organic compounds were formed as an approximately 50 nm thick thin film over a quartz substrate, and a measurement was performed. The absorption spectrum was measured with a UV-VIS spectrophotometer (U-4100, manufactured by Hitachi, Ltd.). The absorption spectrum of the thin film was calculated using an absorbance (-log 10 (%T / (100-%R))), which was obtained from the transmittance (%T) and reflectance (%R) of the substrate and the thin film.

[0448] The measurement was performed on the light-emitting substance in a solution state. Specifically, the absorption spectrum (UV-VIS absorption spectrum) of 3,10PCA2Nbf(IV)-02 was measured in a toluene solution. The absorption spectrum was measured using a UV-VIS spectrophotometer (V550, manufactured by JASCO Corporation).

[0449] Fig.36 and the above structural formulas show that the substances other than the light-emitting substance (the host material) used in the comparative light-emitting devices 1 satisfy the following conditions: the wavelength of the absorption edge having the longest wavelength in the absorption spectrum is longer than or equal to 400 nm; a structure in which two adjacent six-membered aromatic rings are condensed is included; a naphthalene skeleton is included; and a condensed ring formed of only six-membered rings is included; accordingly, the comparative light-emitting devices 1 are each not the light-emitting device of one embodiment of the present invention.

[0450] In particular, among the absorption edges in the absorption spectrum, the absorption edge with the longest wavelength of αN-βNPAnth was located at 420 nm. Furthermore, the absorbance of αN-βNPAnth at a wavelength of 400 nm was 0.29.

[0451] Among the absorption edges in the absorption spectrum of 3,10PCA2Nbf(IV)-02, the absorption edge with the longest wavelength was at 448 nm.

[0452] Fig. 37 shows the luminance-current density characteristics of these comparative light-emitting devices 1, Fig. 38 shows the power efficiency-luminance characteristics of these, Fig. 39 shows the luminance-voltage characteristics of this, Fig. 40 shows the current density-voltage characteristics of these, Fig. 41 shows the blue index luminance characteristics of these and Fig.Figure 42 shows the emission spectra of these. The values ​​of the principal voltage, the principal current, the principal current density, the principal CIE chromaticity, the principal current efficiency, and the principal blue index (BI) at 1000 cd / cm 2 are shown below. The luminance, CIE chromaticity, and emission spectra were measured using a spectroradiometer (SR-UL1R, manufactured by TOPCON TECHNOHOUSE CORPORATION) at normal temperature. [Table 6] Voltage (V) Current (mA) Current density (mA / cm 2 ) Chromaticityx Chromaticity Power efficiency (cd / A) BI(cd / A / y) Light-emitting comparison device 1-0 3,8 0,65 16,18 0,14 0,05 5 104 Light-emitting comparison device 1-1 3,8 0,55 13,87 0,14 0,05 6 107 Light-emitting comparison device 1-2 4,2 1,02 25,60 0,13 0,09 3 38 Light-emitting comparison device 1-3 3,8 0,61 15,33 0,14 0,05 5 106

[0453] Fig. 37 to Fig.42 shows that, among the comparative light-emitting devices 1, there is no significant difference in the characteristics of the comparative light-emitting device 1-0 formed by a continuous vacuum process without releasing a vacuum, the comparative light-emitting device 1-1 exposed to air under light shielding, and the comparative light-emitting device 1-3 exposed to air under orange light irradiation. However, in the comparative light-emitting device 1-2 exposed to air under fluorescent lamp irradiation, both the operating voltage and current efficiency deteriorate significantly. Furthermore, the emission spectrum also changes, resulting in a significantly reduced blue index.

[0454] Fig.Figure 43 shows changes in luminance over the operating time when operating with a constant current at a current density of 50 mA / cm 2 . Fig. 43 shows that in the comparative light-emitting devices 1, the reliability is greatly reduced only in the comparative light-emitting device 1-2 irradiated with the fluorescent lamp. (Manufacturing method of the comparative light-emitting device 2-0)

[0455] First, 100 nm thick silver (Ag) as a reflective electrode and then 85 nm thick indium tin oxide containing silicon oxide (ITSO) as a transparent electrode were sequentially deposited on a glass substrate by sputtering from the substrate side, thereby forming the first electrode 101 with a size of 2 mm × 2 mm. Note that ITSO serves as the anode and, together with the Ag multilayer structure, is considered the first electrode 101.

[0456] Then, a pretreatment for forming the light-emitting device over the substrate was performed by washing the substrate surface with water.

[0457] The substrate was then transferred to a vacuum evaporation device where the pressure was increased to approximately 1 × 10 -4Pa, and vacuum baking was performed at 170 °C for 30 minutes in a heating chamber of the vacuum evaporation device, and then the substrate was cooled for approximately 30 minutes.

[0458] Then, the substrate was attached to a holder provided in a vacuum evaporation device such that the surface on which the first electrode 101 is formed faced downward; over an inorganic insulating film and the first electrode 101, N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and a fluorine-containing electron acceptor material with a molecular weight of 672 (OCHD-003) were co-evaporated to a thickness of 10 nm such that the weight ratio of PCBBiF:OCHD-003 was 1:0.04, thereby forming the hole injection layer 111.

[0459] PCBBiF was deposited by evaporation over the hole injection layer 111 to a thickness of 95 nm, forming the hole transport layer 112.

[0460] Subsequently, over the hole transport layer 112, 11-[(3'-dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr), represented by the structural formula (xix), PCBBiF, and OCPG-006, which is a red phosphorescent light-emitting substance, were co-deposited by co-evaporation to a thickness of 40 nm such that the weight ratio of 11mDBtBPPnfpr:PCBBiF:OCPG-006 was 0.7:0.3:0.05, thereby forming the light-emitting layer 113.

[0461] Next, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), represented by the above structural formula (v), was deposited by evaporation to a thickness of 20 nm to form the first electron-transport layer, and then 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), represented by the above structural formula (xviii), was deposited by evaporation to a thickness of 15 nm to form the second electron-transport layer, thereby forming the electron-transport layer 114. Note that the first electron-transport layer also serves as a hole-blocking layer.

[0462] Next, lithium fluoride (LiF) and ytterbium (Yb) were co-evaporated to a thickness of 2 nm such that the volume ratio of LiF:Yb was 1:1 to form the electron injection layer 115. After that, silver (Ag) and magnesium (Mg) were co-evaporated to a thickness of 20 nm such that the volume ratio of Ag:Mg was 1:0.1, thereby forming the second electrode 102. Over the second electrode 102, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), represented by the above structural formula (v), was deposited to a thickness of 70 nm as a cap layer to improve the light extraction efficiency.

[0463] Subsequently, the light-emitting device was sealed using a glass substrate in a glove box containing a nitrogen atmosphere so that it was not exposed to the air (a UV-curing sealing material was applied to enclose the element, only the UV-curing sealing material was irradiated with UV while preventing the light-emitting device from being irradiated with the UV, and a heat treatment was performed under atmospheric pressure at 80 °C for one hour), and the comparative light-emitting device 2-0 was manufactured. (Manufacturing method of the comparative light-emitting device 2-1)

[0464] The comparative light-emitting device 2-1 was manufactured in a similar manner to the comparative light-emitting device 2-0, except that after the formation of the electron-transport layer in the comparative light-emitting device 1-0, it was left to stand for one hour in the air atmosphere while shielding from light, followed by a heat treatment at 110 °C for one hour in an atmosphere of approximately 1 × 10 -4 Pa or lower, and then the electron injection layer and subsequent components were formed. (Manufacturing method of the comparative light-emitting device 2-2)

[0465] The comparative light-emitting device 2-2 was manufactured in a similar manner to the comparative light-emitting device 2-0, except that after the formation of the electron-transport layer in the comparative light-emitting device 2-0, it was left to stand for one hour in the air atmosphere under irradiation with the fluorescent lamp, followed by a one-hour heat treatment at 110 °C in an atmosphere of approximately 1 × 10 -4 Pa or lower, and then the electron injection layer and subsequent components were formed. Note that the illuminance of the fluorescent lamp was 317 lux. (Manufacturing method of the comparative light-emitting device 2-3)

[0466] The comparative light-emitting device 2-3 was manufactured in a similar manner to the comparative light-emitting device 2-0, except that after the formation of the electron-transport layer in the comparative light-emitting device 2-0, it was allowed to stand for one hour in the air atmosphere under irradiation with orange light, followed by a one-hour heat treatment at 110 °C in an atmosphere of approximately 1 × 10 -4 Pa or lower, and then the electron injection layer and subsequent components were formed. Note that the illuminance of orange light was 111 lux.

[0467] The device structures of the comparative light-emitting devices 2-0 to 2-3 are shown in the table below. [Table 7] Film thickness (nm) Light-emitting comparison device 2-0 Light-emitting comparison device 2-1 Light-emitting comparison device 2-2 Light-emitting comparison device 2-3 Cap layer 70 DBT3P-II second electrode 20 Ag:Mg (1:0.1) 2 LiF:Yb (2:1) Air exposure without (continuous vacuum process) Light shielding Irradiation with the fluorescent lamp Irradiation with orange light Electron transport layer 15 NBPhen 20 2mPCCzPDBq Light-emitting layer 40 11mDBtBPPnfpr:PCBBiF : OCPG-006(0.7:0.3:0.05) Hole transport layer 95 PCBBiF Hole injection layer 10 PCBBiF:OCHD-003(1:0.04) first electrode transparent electrode 85 ITSO reflective electrode 100 Ag

[0468] Fig.44 shows absorption spectra of the organic compounds used in the light-emitting layers of the comparative light-emitting devices 1, the emission spectrum of the fluorescent lamp, and the emission spectrum of orange light.

[0469] It should be noted that the absorption spectrum of the host material was measured in a thin film state. Specifically, the respective organic compounds were formed as an approximately 50 nm thick thin film over a quartz substrate, and a measurement was performed. The absorption spectrum was measured with a UV-VIS spectrophotometer (U-4100, manufactured by Hitachi, Ltd.). The absorption spectrum of the thin film was calculated using an absorbance (-log 10 (%T / (100-%R))), which was obtained from the transmittance (%T) and reflectance (%R) of the substrate and the thin film.

[0470] The measurement was performed on the light-emitting substance in a solution state. Specifically, the absorption spectrum (UV-VIS absorption spectrum) of OCPG-006 was measured in a dichloromethane solution. The absorption spectrum was measured using a UV-VIS spectrophotometer (V550, manufactured by JASCO Corporation).

[0471] Fig.44 and the above structural formulas show that 11mDBtBPPnfpr as a substance other than the light-emitting substance used in the comparative light-emitting devices 1 satisfies the following conditions: the absorption edge having the longest wavelength in the absorption spectrum is located at a wavelength longer than or equal to 400 nm; a structure in which two adjacent six-membered aromatic rings are condensed, a naphthalene skeleton is included; and a condensed ring formed of only six-membered rings is included; accordingly, the comparative light-emitting devices 1 are each not the light-emitting device of one embodiment of the present invention.

[0472] In particular, among the absorption edges in the absorption spectra, the absorption edges with the longest wavelength of PCBBiF and 11mDBtBPPnfpr were located at 399 nm and 421 nm, respectively. Furthermore, the absorbances of PCBBiF and 11mDBtBPPnfpr at a wavelength of 400 nm were 0.04 and 0.24, respectively.

[0473] Among the absorption edges in the absorption spectrum of OCPG-006, the absorption edge with the longest wavelength was at 621 nm. The molar absorption coefficient of OCPG-006 at a wavelength of 429 nm was 13920 M -1 ·cm -1 .

[0474] Fig. 45 shows the luminance-current density characteristics of these comparative light-emitting devices 1, Fig. 46 shows the power efficiency-luminance characteristics of these, Fig. 47 shows the luminance-voltage characteristics of this, Fig. 48 shows the current density-voltage characteristics of this, Fig.49 shows the external quantum efficiency-luminance properties of these and Fig. Figure 50 shows the emission spectra of these. The values ​​of the principal voltage, the principal current, the principal current density, the principal CIE chromaticity, and the principal current efficiency at 1000 cd / cm 2 are shown below. The luminance, CIE chromaticity, and emission spectra were measured using a spectroradiometer (SR-UL1R, manufactured by TOPCON TECHNOHOUSE CORPORATION) at normal temperature. [Table 8] Voltage (V) Current (mA) Current density (mA / cm 2 ) Chromaticityx Chromaticity Power efficiency (cd / A) external quantum efficiency (%) Light-emitting comparison device 2-0 2,6 0,07 1,64 0,69 0,31 50 43 Light-emitting comparison device 2-1 2,7 0,08 2,03 0,70 0,30 51 45 Light-emitting comparison device 2-2 2,7 0,08 2,01 0,70 0,30 47 42 Light-emitting comparison device 2-3 2,6 0,06 1,49 0,69 0,31 58 48

[0475] Fig. 45 to Fig.50 show that, in the comparative light-emitting devices 2, there is no great deterioration in the characteristics of the comparative light-emitting device 2-0 manufactured by a continuous vacuum process without releasing a vacuum, the comparative light-emitting device 2-1 exposed to air under light shielding, and the comparative light-emitting device 2-3 exposed to air under irradiation with orange light, and nevertheless, in the characteristics of the comparative light-emitting device 2-2 exposed to air under irradiation with the fluorescent lamp, the emission efficiency, such as the current efficiency and the external quantum efficiency, deteriorates.

[0476] Fig. Figure 51 shows changes in luminance over the operating time when operating with a constant current at a current density of 50 mA / cm 2 . Fig.51 shows that among the comparative light-emitting devices 2, the reliability is greatly reduced only in the comparative light-emitting device 2-2 irradiated with the fluorescent lamp.

[0477] Fig. 52A is a graph showing the absorbances of the organic compounds (host materials) other than the light-emitting substance used in one of the light-emitting devices of one embodiment of the present invention (the light-emitting devices 1 to 4), and Fig.52B is a graph showing the absorbances of organic compounds (host materials) other than the light-emitting substance used in the light-emitting devices as comparative examples (the comparative light-emitting devices 1 or the comparative light-emitting devices 2). Note that these absorbances are obtained by measuring a 50 nm thick film containing the organic compound to be measured. In this way, in the light-emitting device of one embodiment of the present invention using a substance having an absorbance of less than or equal to 0.01 at a wavelength of 400 nm to 475 nm, a reduction in initial characteristics and reliability can be prevented even when white light irradiation is performed under air exposure.It should be noted that even with an absorbance greater than or equal to 0.01 at a wavelength of 400 nm to 475 nm, in the case of an organic compound without a fragile naphthalene structure, such as BP-Icz(II)Tzn, a light-emitting device with advantageous properties can also be obtained by air exposure and white light irradiation; however, even in the case of an organic compound without a fragile naphthalene structure, the absorbance at 400 nm to 475 nm is preferably less than or equal to 0.01.

[0478] Fig.Figure 53 shows the molar absorption coefficients of the light-emitting substances used in the light-emitting devices 1 to 5. In the light-emitting device of one embodiment of the present invention, even if the light-emitting substance contained together with the host material in the light-emitting layer has a molar absorption coefficient of greater than or equal to 1000 M at a wavelength of 400 nm to 475 nm, the characteristics of the light-emitting device are not adversely affected. -1 ·cm -1 has. Reference symbol

[0479] 100A: display device, 100B: display device, 100C: display device, 100E: display device, 100D: display device, 101A: first electrode group, 101a: first electrode, 101b: first electrode, 101: first electrode, 102: second electrode, 103a: organic compound layer, 103b: organic compound layer, 103Bf: organic compound film, 103Gf: organic compound film, 103Rf: organic compound film, 103: organic compound layer, 104: first layer, 105: second layer, 110B: subpixel, 110G: subpixel, 110R: subpixel, 110: subpixel, 111a: hole injection layer, 111b: hole injection layer, 111: Hole injection layer, 112: Hole transport layer, 112a: Hole transport layer, 112b: Hole transport layer, 112B: Conductive layer, 112R: Conductive layer, 113: Light-emitting layer, 113a: Light-emitting layer, 113b: Light-emitting layer, 114: Electron transport layer, 114a: Electron transport layer, 114b: Electron transport layer,115: Electron injection layer, 116: Charge generation layer, 117: P-type layer, 118: Electron relay layer, 119: Electron injection buffer layer, 120: Substrate, 122: Resin layer, 125f: Inorganic insulating film, 125: Inorganic insulating layer, 126R: Conductive layer, 126B: Conductive layer, 127a: Insulating layer, 127f: Insulating film, 127: Insulating layer, 128: Layer, 129R: Conductive layer, 129B: Conductive layer, 130a: Light-emitting device, 130B: Light-emitting device, 130b: Light-emitting device, 130G: Light-emitting device, 130R: Light-emitting device, 130: Light-emitting device, 131: Protective layer, 132B: ink layer, 132G: ink layer, 132R: ink layer, 135: first layer, 135A: first layer group, 135a: first layer, 135b: first layer, 135R: first layer, 135G: first layer, 135B: first layer, 136: common layer, 140: connecting portion, 141: area, 142: adhesive layer, 151B: conductive layer,151C: conductive layer, 151cf: conductive film, 151f: conductive film, 151G: conductive layer, 151R: conductive layer, 151: conductive layer, 152B: conductive layer, 152C: conductive layer, 152f: conductive film, 152G: conductive layer, 152R: conductive layer, 152: conductive layer, 153: insulating layer, 156B: insulating layer, 156C: insulating layer, 156f: insulating film, 156G: insulating layer, 156R: insulating layer, 156: insulating layer, 157: opaque layer, 158B: sacrificial layer, 158Bf: sacrificial film, 158G: sacrificial layer, 158Gf: sacrificial film, 158R: sacrificial layer, 158Rf: sacrificial film, 159B: mask layer, 159Bf: mask layer, 159G: mask layer, 159Gf: mask film, 159R: mask layer, 159Rf: mask film, 166: conductive layer, 171: insulating layer, 172: conductive layer, 173: insulating layer, 174: insulating layer, 175: insulating layer, 176: terminal plug, 177: pixel portion, 178: pixel, 179: conductive layer, 190B: photoresist mask, 190G: photoresist mask, 190R: photoresist mask, 191: photoresist mask,201: Transistor, 204: Connection section, 205: Transistor, 211: Insulating layer, 213: Insulating layer, 214: Insulating layer, 215: Insulating layer, 221: Conductive layer, 222a: Conductive layer, 222b: Conductive layer, 223: Conductive layer, 224B: Conductive layer, 224C: Conductive layer, 224G: Conductive layer, 224R: Conductive layer, 231: Semiconductor layer, 240: Capacitor, 241: Conductive layer, 242: Connection layer, 243: Insulating layer, 245: Conductive layer, 254: Insulating layer, 255: Insulating layer, 256: Terminal plug, 261: Insulating layer, 271: Terminal plug, 280: Display module, 281: Display section, 282: Circuit section, 283a: pixel circuit, 283: pixel circuit section, 284a: pixel, 284: pixel section, 285: terminal section, 286: wiring section, 290: FPC, 291: substrate, 292: substrate, 301: substrate, 310: transistor, 311: conductive layer, 312: low-resistance region, 313: insulating layer, 314: insulating layer, 315: element insulating layer, 351: substrate,352: substrate, 353: FPC, 354: IC, 355: line, 356: circuit, 501: first electrode, 502: second electrode, 513: charge generation layer, 700A: electronic device, 700B: electronic device, 721: housing, 723: mounting portion, 727: earphone portion, 750: earphone, 751: display panel, 753: optical component, 756: display portion, 757: frame, 758: nose pad, 800A: electronic device, 800B: electronic device, 820: display portion, 821: housing, 822: communication portion, 823: mounting portion, 824: control portion, 825: imaging portion, 827: earphone portion, 832: Lens, 1117: opaque layer, 6500: electronic device, 6501: housing, 6502: display section, 6503: power button, 6504: knob, 6505: speaker, 6506: microphone, 6507: camera, 6508: light source, 6510: protective component, 6511: display panel, 6512: optical component, 6513: touch sensor panel, 6515: FPC, 6516: IC, 6517: printed circuit board, 6518: battery,7000: Display section, 7100: TV, 7151: Remote control, 7171: Cabinet, 7173: Stand, 7200: Laptop PC, 7211: Cabinet, 7212: Keyboard, 7213: Pointing device, 7214: External connection port, 7300: Digital signage, 7301: Cabinet, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Column, 7411: Information terminal, 9000: Cabinet, 9001: Display section, 9002: Camera, 9003: Speaker, 9005: Control button, 9006: Connection port, 9007: Sensor, 9008: Microphone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Joint, 9171: Portable information terminal, 9172: Portable information terminal, 9173: Tablet terminal, 9200: Portable information terminal, 9201: Portable information terminal, QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2018-521459

[0007]

Claims

[1] A light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, the group of light-emitting devices comprising: a first electrode group formed over the same insulating surface; a second electrode facing the first electrode group; and a first layer group positioned between the first electrode group and the second electrode, wherein the first electrode group comprises a plurality of first electrodes each independent of each other for each of the plurality of light-emitting devices, wherein the first layer group comprises a plurality of first layers, each of which is independent of each other for each of the plurality of light-emitting devices, wherein the second electrode is a continuous conductive layer shared by the plurality of light-emitting devices, wherein the light-emitting device comprises a first electrode of the first electrode group, the second electrode and a first layer of the first layer group, wherein the second electrode and the first layer overlap with the first electrode, wherein the first layer comprises a light-emitting layer containing an emission center substance and a first substance, wherein a wavelength of an absorption edge with the longest wavelength in an absorption spectrum of the first substance is shorter than 400 nm, and wherein a distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm. [2] A light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, the group of light-emitting devices comprising: a first electrode group formed over the same insulating surface; a second electrode facing the first electrode group; and a first layer group positioned between the first electrode group and the second electrode, wherein the first electrode group comprises a plurality of first electrodes each independent of each other for each of the plurality of light-emitting devices, wherein the first layer group comprises a plurality of first layers, each of which is independent of each other for each of the plurality of light-emitting devices, wherein the second electrode is a continuous conductive layer shared by the plurality of light-emitting devices, wherein the light-emitting device comprises a first electrode of the first electrode group, the second electrode and a first layer of the first layer group, wherein the second electrode and the first layer overlap with the first electrode, wherein the first layer comprises a light-emitting layer containing an emission center substance and a first substance, wherein the first substance does not comprise a condensed ring formed solely from six-membered rings, and wherein a distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm. [3] A light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, the group of light-emitting devices comprising: a first electrode group formed over the same insulating surface; a second electrode facing the first electrode group; and a first layer group positioned between the first electrode group and the second electrode, wherein the first electrode group comprises a plurality of first electrodes each independent of each other for each of the plurality of light-emitting devices, wherein the first layer group comprises a plurality of first layers, each of which is independent of each other for each of the plurality of light-emitting devices, wherein the second electrode is a continuous conductive layer shared by the plurality of light-emitting devices, wherein the light-emitting device comprises a first electrode of the first electrode group, the second electrode and a first layer of the first layer group, wherein the second electrode and the first layer overlap with the first electrode, wherein the first layer comprises a light-emitting layer containing an emission center substance and a first substance, wherein the first substance has neither a structure in which two adjacent six-membered aromatic rings are condensed, nor a structure in which two adjacent six-membered heteroaromatic rings are condensed, nor a structure in which a six-membered aromatic ring and a six-membered heteroaromatic ring which are adjacent to each other are condensed, and wherein a distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm. [4] A light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, the group of light-emitting devices comprising: a first electrode group formed over the same insulating surface; a second electrode facing the first electrode group; and a first layer group positioned between the first electrode group and the second electrode, wherein the first electrode group comprises a plurality of first electrodes each independent of each other for each of the plurality of light-emitting devices, wherein the first layer group comprises a plurality of first layers, each of which is independent of each other for each of the plurality of light-emitting devices, wherein the second electrode is a continuous conductive layer shared by the plurality of light-emitting devices, wherein the light-emitting device comprises a first electrode of the first electrode group, the second electrode and a first layer of the first layer group, wherein the second electrode and the first layer overlap with the first electrode, wherein the first layer comprises a light-emitting layer containing an emission center substance and a first substance, wherein the first substance does not have a naphthalene structure, and wherein a distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm. [5] A light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, the group of light-emitting devices comprising: a first electrode group formed over the same insulating surface; a second electrode facing the first electrode group; and a first layer group positioned between the first electrode group and the second electrode, wherein the first electrode group comprises a plurality of first electrodes each independent of each other for each of the plurality of light-emitting devices, wherein the first layer group comprises a plurality of first layers, each of which is independent of each other for each of the plurality of light-emitting devices, wherein the second electrode is a continuous conductive layer shared by the plurality of light-emitting devices, wherein the light-emitting device comprises a first electrode of the first electrode group, the second electrode and a first layer of the first layer group, wherein the second electrode and the first layer overlap with the first electrode, wherein the first layer comprises a light-emitting layer containing an emission center substance and a first substance, wherein the first substance comprises neither a naphthalene ring nor a phenanthrene ring nor a naphthacene ring, and wherein a distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm. [6] A light-emitting device of a plurality of light-emitting devices included in a group of light-emitting devices, the group of light-emitting devices comprising: a first electrode group formed over the same insulating surface; a second electrode facing the first electrode group; and a first layer group positioned between the first electrode group and the second electrode, wherein the first electrode group comprises a plurality of first electrodes each independent of each other for each of the plurality of light-emitting devices, wherein the first layer group comprises a plurality of first layers, each of which is independent of each other for each of the plurality of light-emitting devices, wherein the second electrode is a continuous conductive layer shared by the plurality of light-emitting devices, wherein the light-emitting device comprises a first electrode of the first electrode group, the second electrode and a first layer of the first layer group, wherein the second electrode and the first layer overlap with the first electrode, wherein the first layer comprises a light-emitting layer containing an emission center substance and a first substance, wherein the first substance comprises a condensed ring, wherein in the condensed ring a six-membered ring and a five-membered ring are alternately condensed, and wherein a distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 2 µm and less than or equal to 5 µm. [7] The light-emitting device according to any one of claims 2 to 6, wherein a wavelength of an absorption edge having the longest wavelength in an absorption spectrum of the first substance is shorter than 400 nm. [8] The light-emitting device according to claim 7, wherein a wavelength of an absorption edge having the longest wavelength in an absorption spectrum of the light-emitting substance is longer than or equal to 400 nm. [9] The light-emitting device according to any one of claims 2 to 6, wherein the first substance does not absorb light having a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm. [10] The light-emitting device according to claim 7, wherein the light-emitting substance absorbs light having a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm. [11] The light-emitting device according to any one of claims 2 to 6, wherein a difference between a wavelength of an absorption edge having the longest wavelength in an absorption spectrum of the light-emitting substance and a wavelength of an absorption edge having the longest wavelength in an absorption spectrum of the first substance is greater than or equal to 60 nm. [12] The light-emitting device according to any one of claims 2 to 6, wherein an absorbance of a 50 nm thick film containing the first substance at a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm is less than or equal to 0.

01. [13] The light-emitting device according to claim 7, wherein a molar absorption coefficient of the light-emitting substance at a wavelength longer than or equal to 400 nm and shorter than or equal to 475 nm is greater than or equal to 1000 M -1 ·cm -1 amounts.

Images