Light emitting device

Abstract

Provided is a light emitting device which can be used in a high-definition display device and has a low driving voltage and good current efficiency. The invention provides a tandem type light-emitting device which is manufactured through a photoetching process and comprises a plurality of light-emitting units and intermediate layers located among the light-emitting units, the intermediate layer includes a metal or a metal oxide, a first region including a first organic compound having a first pi-electron-deficient heteroaromatic ring having an electron-donating group, and a second organic compound having a second pi-electron-deficient heteroaromatic ring, and the LUMO level of the second organic compound is less than the LUMO level of the first organic compound by 0.30 eV or more.

Description

Technical Field

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

[0002] Note that one embodiment of the present invention is not limited to the above-mentioned technical field. As an example of the technical field of one embodiment of the present invention, a semiconductor device, a display device, a light-emitting device, a power storage device, a storage device, an electronic device, a lighting device, an input device (e.g., a touch sensor), an input-output device (e.g., a touch panel), and a driving method or a manufacturing method of the above-mentioned device can be cited. Background Art

[0003] In recent years, display devices have been used for various purposes. For example, as large-scale display devices, research and development has been carried out for home television devices (also called televisions or television receivers), digital signage, and public information displays (PID: Public Information Display), and as small-scale display devices, research and development has been carried out for smartphones or tablet terminals equipped with touch panels.

[0004] At the same time, the display device is also being made higher-definition. As equipment that requires a high-definition display device, for example, equipment for virtual reality (VR), augmented reality (AR), alternative reality (SR), and mixed reality (MR) is being developed.

[0005] As display elements for display devices, the development of light-emitting devices (also called light-emitting elements) is becoming increasingly popular. Light-emitting devices (also called EL devices, EL elements) that utilize the electroluminescence (hereinafter referred to as EL) phenomenon, especially light-emitting devices that mainly use organic compounds, have the following characteristics: they are easy to achieve thinness and lightness; they can respond to input signals at high speed; and they can be driven using a DC constant voltage power supply, etc., so they are preferably used in display devices.

[0006] In order to obtain a higher-definition light-emitting device using a light-emitting device, a technique for patterning an organic layer using photolithography using a photoresist or the like instead of a vapor deposition method using a metal mask has been studied. By using photolithography, a high-definition display device with an EL layer having a spacing of several μm can be obtained (for example, see Patent Document 1).

[0007] [Patent Document 1] Japanese PCT International Application Translation No. 2018-521459 [Patent Document 2] International Patent Application Publication No. 2021 / 045178 Summary of the invention

[0008] It has been known that the initial characteristics and reliability of the EL layer in a light-emitting device are affected when it is exposed to atmospheric components such as water and oxygen, and the EL layer is processed in a near-vacuum atmosphere in a common procedure. In particular, an electron injection layer or an intermediate layer in a light-emitting device having a tandem structure uses a material having a donor property, typically an alkali metal or an alkaline earth metal or a compound thereof. The above metals and compounds have extremely high reactivity with water or oxygen, and when the surface of the EL layer is exposed to the atmosphere, they are instantly degraded and do not function as an intermediate layer.

[0009] However, in the process of processing by the above-mentioned photolithography method, the surface of the EL layer has to be exposed to the atmosphere. Therefore, it is difficult for a light-emitting device processed by the photolithography method to obtain good characteristics.

[0010] In particular, when processing is performed using photolithography, an increase in driving voltage often becomes a problem.

[0011] Therefore, one of the objects of one embodiment of the present invention is to provide a novel light-emitting device having a tandem structure. One of the objects of another embodiment of the present invention is to provide a light-emitting device having a tandem structure with good efficiency. One of the objects of one embodiment of the present invention is to provide a light-emitting device having a tandem structure with a low driving voltage. One of the objects of one embodiment of the present invention is to provide a light-emitting device having a tandem structure with good reliability. One of the objects of another embodiment of the present invention is to provide a light-emitting device having a tandem structure with good efficiency and reliability. One of the objects of another embodiment of the present invention is to provide a light-emitting device having a tandem structure with a low driving voltage and good reliability. One of the objects of another embodiment of the present invention is to provide a light-emitting device having a tandem structure with a low driving voltage and good efficiency and reliability.

[0012] In addition, one of the objects of one embodiment of the present invention is to provide a novel light-emitting device having a tandem structure manufactured by a photolithography process. One of the objects of another embodiment of the present invention is to provide a light-emitting device having a tandem structure manufactured by a photolithography process and having good efficiency. One of the objects of one embodiment of the present invention is to provide a light-emitting device having a tandem structure manufactured by a photolithography process and having a low driving voltage. One of the objects of one embodiment of the present invention is to provide a light-emitting device having a tandem structure manufactured by a photolithography process and having good reliability. One of the objects of another embodiment of the present invention is to provide a light-emitting device having a tandem structure manufactured by a photolithography process and having good luminous efficiency and reliability. One of the objects of another embodiment of the present invention is to provide a light-emitting device having a tandem structure manufactured by a photolithography process and having a low driving voltage and good reliability. One of the objects of another embodiment of the present invention is to provide a light-emitting device having a tandem structure manufactured by a photolithography process and having a low driving voltage and good luminous efficiency and reliability.

[0013] In addition, one of the purposes of one embodiment of the present invention is to provide a novel light-emitting device with a tandem structure that can be used in a high-definition display device. One of the purposes of another embodiment of the present invention is to provide a light-emitting device with a tandem structure with good efficiency that can be used in a high-definition display device. One of the purposes of one embodiment of the present invention is to provide a light-emitting device with a tandem structure with a low driving voltage that can be used in a high-definition display device. One of the purposes of one embodiment of the present invention is to provide a light-emitting device with a tandem structure with good reliability that can be used in a high-definition display device. One of the purposes of another embodiment of the present invention is to provide a light-emitting device with a tandem structure with good luminous efficiency and reliability that can be used in a high-definition display device. One of the purposes of another embodiment of the present invention is to provide a light-emitting device with a tandem structure with a low driving voltage and good reliability that can be used in a high-definition display device. One of the purposes of another embodiment of the present invention is to provide a light-emitting device with a tandem structure with a low driving voltage and good luminous efficiency and reliability that can be used in a high-definition display device.

[0014] One of the purposes of another embodiment of the present invention is to provide a display device with high reliability. One of the purposes of another embodiment of the present invention is to provide a display device with low power consumption. One of the purposes of another embodiment of the present invention is to provide a high-definition display device. One of the purposes of another embodiment of the present invention is to provide a display device with high definition and good reliability. One of the purposes of another embodiment of the present invention is to provide a display device with high definition and low power consumption.

[0015] Note that the description of these objectives does not prevent the existence of other objectives. One embodiment of the present invention does not need to achieve all of the above objectives. Objectives other than the above objectives can be extracted from the description of the specification, drawings, and claims.

[0016] One embodiment of the present invention is a light-emitting device, which is one of a plurality of light-emitting devices included in a light-emitting device group, wherein the light-emitting device group includes a first electrode group formed on the same insulating surface, a second electrode opposite to the first electrode group, and a first layer group located between the first electrode group and the second electrode, wherein the first electrode group is composed of a plurality of first electrodes independently in each of the plurality of light-emitting devices, the first layer group is composed of a plurality of first layers independently in each of the plurality of light-emitting devices, the second electrode is a continuous conductive layer shared by the plurality of light-emitting devices, and the light-emitting device includes a first electrode of one of the first electrode groups, a second electrode, a first layer of one of the first layer groups, the second electrode and the first layer overlap with the first electrode The first layer includes a first light-emitting layer, a second light-emitting layer and an intermediate layer located between the first light-emitting layer and the second light-emitting layer, the intermediate layer includes a first region including a metal or a metal oxide, a first organic compound and a second organic compound, the first organic compound is an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group, the second organic compound is an organic compound including a second π-electron-deficient heteroaromatic ring, the LUMO energy level of the second organic compound is less than 0.20 eV than the LUMO energy level of the first organic compound, and the interval between the first layer included in the light-emitting device and the first layer included in other light-emitting devices adjacent to the light-emitting device is greater than 0.5 μm and less than 5 μm.

[0017] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein when the LUMO energy level of the first organic compound is LUMO1 (eV), the LUMO energy level (LUMO2 (eV)) of the second organic compound satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.20.

[0018] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein when the LUMO energy level of the first organic compound is LUMO1 (eV), the LUMO energy level (LUMO2 (eV)) of the second organic compound satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.30.

[0019] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first π-electron-deficient heteroaromatic ring is a heteroaromatic ring including two or more pyridine rings.

[0020] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first organic compound has an acidity coefficient pKa of 8 or more.

[0021] In addition, another embodiment of the present invention is the light-emitting device having the above structure, wherein the second organic compound has a glass transition temperature of 100° C. or higher.

[0022] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first π-electron-deficient heteroaromatic ring is different from the second π-electron-deficient heteroaromatic ring.

[0023] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the second organic compound has an azole ring (imidazole ring, pyrazole ring, oxazole ring, thiazole ring), a triazole ring, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or a triazine ring.

[0024] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the acidity coefficient pKa of the second organic compound is less than 4.

[0025] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the second organic compound has a solubility parameter δ of 4.0 MPa. 0.5 The following polarization term δp.

[0026] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first light-emitting layer is located closer to the first electrode than the second light-emitting layer, the first light-emitting layer contains a third organic compound, the third organic compound contains a third π-electron-deficient heteroaromatic ring, and the third π-electron-deficient heteroaromatic ring is the same as the second π-electron-deficient heteroaromatic ring.

[0027] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first light-emitting layer is located closer to the first electrode than the second light-emitting layer, and the first light-emitting layer contains a third organic compound, which is the same organic compound as the second organic compound.

[0028] Another embodiment of the present invention is a light-emitting device having the above structure, comprising a first electron transport layer between the first light-emitting layer and the intermediate layer, the first electron transport layer containing a fourth organic compound, and the fourth organic compound is an organic compound different from the third organic compound.

[0029] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the metal is a metal of Group 1, Group 2, Group 3, Group 11, Group 12, or Group 13.

[0030] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the metal is a metal of Group 3, Group 11, Group 12, or Group 13.

[0031] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first π-electron-deficient heteroaromatic ring includes a phenanthroline ring.

[0032] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first π-electron-deficient heteroaromatic ring is a 1,10-phenanthroline ring having an electron-donating group at at least one of the 4-position and the 7-position.

[0033] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the electron-donating group is any one or more of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group and a heterocyclic amino group.

[0034] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first organic compound has an acidity coefficient pKa of 8 or more.

[0035] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein when the threshold value of the electron density distribution in the atomic units is 0.0004e / a0 3 The minimum value of the electrostatic potential of the first organic compound is -0.085E h the following.

[0036] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the metal or metal oxide, the first organic compound, and the second organic compound are mixed in the first region.

[0037] Another embodiment of the present invention is a light-emitting device having the above structure, wherein a layer containing a metal or a metal oxide and a layer in which the first organic compound and the second organic compound are mixed are stacked in the first region.

[0038] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the layer containing metal or metal oxide is located between the layer in which the first organic compound and the second organic compound are mixed and the second light-emitting layer.

[0039] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the spin density of the first region measured by an electron spin resonance method is 5×10 16 spins / cm 3 above.

[0040] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the intermediate layer includes a second region, the second region is located between the first region and the second electrode, and the second region contains a third organic compound with hole transport properties and a first substance with acceptor properties for the third organic compound.

[0041] In addition, another embodiment of the present invention is a light-emitting device having the above structure, further comprising a third region containing a second substance and located between the first region and the second region.

[0042] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the spin density of the second region measured by an electron spin resonance method is 1×10 17 spins / cm 3 above.

[0043] In addition, another embodiment of the present invention is a light-emitting device having the above structure, further comprising a second layer, the second layer being a layer shared by a plurality of light-emitting devices, and the second layer being located between the first layer and the second electrode.

[0044] Furthermore, another embodiment of the present invention is a display device including the above-mentioned light-emitting device.

[0045] Furthermore, another embodiment of the present invention is a display module including the above-mentioned display device and at least one of a connector and an integrated circuit.

[0046] In addition, another embodiment of the present invention is an electronic device including the above-mentioned display module and at least one of a housing, a battery, a camera, a speaker, and a microphone.

[0047] According to one embodiment of the present invention, a novel light-emitting device having a series structure can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a series structure with good efficiency can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a series structure with a low driving voltage can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a series structure with good reliability can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a series structure with good efficiency and reliability can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a series structure with a low driving voltage and good reliability can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a series structure with a low driving voltage and good efficiency and reliability can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a series structure with a low driving voltage and good efficiency and reliability can be provided.

[0048] In addition, according to one embodiment of the present invention, a novel light-emitting device having a tandem structure manufactured by a photolithography process can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a tandem structure with good efficiency manufactured by a photolithography process can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a tandem structure with low driving voltage manufactured by a photolithography process can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a tandem structure with good reliability manufactured by a photolithography process can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a tandem structure with good luminous efficiency and reliability manufactured by a photolithography process can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a tandem structure with low driving voltage and good reliability manufactured by a photolithography process can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a tandem structure with low driving voltage and good luminous efficiency and reliability manufactured by a photolithography process can be provided. In addition, according to one embodiment of the present invention, a light-emitting device having a tandem structure with low driving voltage and good luminous efficiency and reliability manufactured by a photolithography process can be provided.

[0049] In addition, according to one embodiment of the present invention, a novel light-emitting device with a series structure that can be used in a high-definition display device can be provided. In addition, according to one embodiment of the present invention, a light-emitting device with a series structure with good efficiency that can be used in a high-definition display device can be provided. In addition, according to one embodiment of the present invention, a light-emitting device with a series structure with a low driving voltage that can be used in a high-definition display device can be provided. In addition, according to one embodiment of the present invention, a light-emitting device with a series structure with good reliability that can be used in a high-definition display device can be provided. In addition, according to one embodiment of the present invention, a light-emitting device with a series structure with good luminous efficiency and reliability that can be used in a high-definition display device can be provided. In addition, according to one embodiment of the present invention, a light-emitting device with a series structure with a low driving voltage and good reliability that can be used in a high-definition display device can be provided. In addition, according to one embodiment of the present invention, a light-emitting device with a series structure with a low driving voltage and good luminous efficiency and reliability that can be used in a high-definition display device can be provided.

[0050] In addition, according to one embodiment of the present invention, a display device with high reliability can be provided. In addition, according to one embodiment of the present invention, a display device with low power consumption can be provided. In addition, according to one embodiment of the present invention, a high-definition display device can be provided. In addition, according to one embodiment of the present invention, a display device with high definition and good reliability can be provided. In addition, according to one embodiment of the present invention, a display device with high definition and low power consumption can be provided.

[0051] Note that the description of these effects does not prevent the existence of other effects. One embodiment of the present invention does not necessarily have all of the above effects. Effects other than the above effects can be extracted from the description of the specification, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is a diagram showing a light emitting device; Figure 2 is a diagram showing a light emitting device; Figure 3A and Figure 3B is a top view and a cross-sectional view of the light emitting device; FIG. 4A to FIG. 4E is a cross-sectional view showing an example of a method for manufacturing a display device; FIG. 5A to FIG. 5D is a cross-sectional view showing an example of a method for manufacturing a display device; FIG. 6A to FIG. 6D is a cross-sectional view showing an example of a method for manufacturing a display device; FIG. 7A to FIG. 7C is a cross-sectional view showing an example of a method for manufacturing a display device; FIG. 8A to FIG. 8C is a cross-sectional view showing an example of a method for manufacturing a display device; 9A to 9C is a cross-sectional view showing an example of a method for manufacturing a display device; Fig. 10A and Fig. 10B is a perspective view showing a structural example of a display module; Fig.11A and Fig. 11B is a cross-sectional view 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 is a diagram showing an example of an electronic device; FIG. 17A to FIG. 17F is a diagram showing an example of an electronic device; FIG. 18A to FIG. 18G is a diagram showing an example of an electronic device; FIG. 19A to FIG. 19C is the analysis result of the spin density distribution in the ground state of the composite material; Fig. 20A and Fig. 20B It is the analysis result of the electrostatic potential diagram in the ground state of organic compounds; FIG. 21A to FIG. 21C It is the analysis result of the electrostatic potential diagram of the composite material in the ground state; Fig. 22 is a graph showing luminance-current density characteristics of the light emitting devices 1 - 1 to 1 - 8 ; Fig.23 is a diagram showing brightness-voltage characteristics of the light emitting devices 1 - 1 to 1 - 8 ; Fig.24 is a graph showing current efficiency-current density characteristics of the light emitting devices 1 - 1 to 1 - 8 ; Fig.25 is a graph showing current density-voltage characteristics of the light emitting devices 1 - 1 to 1 - 8 ; Fig.26 is a diagram showing electroluminescence spectra of light emitting devices 1 - 1 to 1 - 8 ; Fig. 27 is a graph showing current density-voltage characteristics of the light emitting devices 1 - 1 to 1 - 8 ; Fig.28 The current density of the light emitting device 1-1 to the light emitting device 1-8 is 50 mA / cm 2 A graph showing the relationship between the voltage at θ and the LUMO energy level of the second organic compound; Fig.29 is a graph showing the luminance-current density characteristics of the light emitting devices 2-1 to 2-4; Fig.30 is a diagram showing the brightness-voltage characteristics of the light emitting devices 2-1 to 2-4; Fig.31 is a graph showing current efficiency-luminance characteristics of the light emitting devices 2-1 to 2-4; Fig.32 is a graph showing current density-voltage of the light emitting devices 2-1 to 2-4; Fig.33 is a diagram showing electroluminescence spectra of light emitting devices 2-1 to 2-4; Fig.34 is a diagram showing the brightness-current density characteristics of the light-emitting device 3-1 and the light-emitting device 3-2; Fig.35 is a diagram showing the brightness-voltage characteristics of the light emitting device 3-1 and the light emitting device 3-2; Fig.36 is a diagram showing current efficiency-current density characteristics of the light emitting device 3-1 and the light emitting device 3-2; Fig.37is a diagram showing current density-voltage characteristics of the light emitting device 3-1 and the light emitting device 3-2; Fig.38 is a diagram showing electroluminescence spectra of the light emitting device 3-1 and the light emitting device 3-2; Fig.39 is a diagram showing normalized brightness-time variation characteristics of the light emitting device 3-1 and the light emitting device 3-2; Fig.40 is a diagram showing the brightness-current density characteristics of the light emitting device 4-1, the light emitting device 4-2, the light emitting device 4-3, and the light emitting device 4-4; Fig.41 is a diagram showing the brightness-voltage characteristics of the light emitting device 4-1, the light emitting device 4-2, the light emitting device 4-3, and the light emitting device 4-4; Fig.42 is a graph showing current efficiency-current density characteristics of the light emitting device 4-1, the light emitting device 4-2, the light emitting device 4-3, and the light emitting device 4-4; Fig.43 is a diagram showing current density-voltage characteristics of the light emitting device 4-1, the light emitting device 4-2, the light emitting device 4-3, and the light emitting device 4-4; Fig.44 1 is a diagram showing electroluminescence spectra of the light emitting device 4 - 1 , the light emitting device 4 - 2 , the light emitting device 4 - 3 , and the light emitting device 4 - 4 . DETAILED DESCRIPTION

[0053] The embodiments are described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and a person skilled in the art can easily understand that the mode and details can be transformed into various forms without departing from the purpose and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the contents described in the embodiments shown below.

[0054] Note that in this specification, etc., a device manufactured using a metal mask or FMM (Fine Metal Mask) is sometimes referred to as a device having an MM (Metal Mask) structure. In addition, in this specification, etc., a device manufactured without using a metal mask or FMM is sometimes referred to as a device having an MML (Metal Mask Less) structure.

[0055] Implementation Method 1 Compared with a general light-emitting device including only one light-emitting unit between electrodes, a tandem light-emitting device including a plurality of light-emitting units between a pair of electrodes and sandwiching an intermediate layer for generating charges between the plurality of light-emitting units can obtain higher current efficiency.

[0056] The intermediate layer of the tandem light-emitting device includes a charge generation layer (CGL). The CGL is a layer that generates electrons and holes by charge separation caused by application of voltage.

[0057] As the CGL, it is preferred to use a stack of the following layers: a layer containing a material having hole transport properties and a material having electron acceptor properties for the material having hole transport properties (P-type CGL); a layer containing a material having electron transport properties and a material having electron donor properties for the material having electron transport properties (N-type CGL). This makes it easier to inject holes or electrons into each light-emitting unit, thereby reducing the driving voltage.

[0058] This is due to the following reasons: the holes generated in the P-type CGL are injected into the hole transport layer of the light-emitting unit on the cathode side through the hole-transporting material contained in the P-type CGL, and the electrons generated in the N-type CGL are injected into the electron transport layer of the light-emitting unit on the anode side through the electron-transporting material contained in the N-type CGL, thereby reducing the carrier injection barrier.

[0059] Here, as one of the methods for forming an organic compound film in a predetermined shape at a predetermined position, vacuum evaporation using a metal mask (mask evaporation) is widely used. However, in recent years, with the progress of high density and high definition, high definition using mask evaporation has reached its limit due to various problems such as alignment accuracy and the spacing between the substrate and the mask.

[0060] On the other hand, photolithography is a processing method that can form dense patterns compared to mask evaporation. Furthermore, since photolithography can easily achieve large areas, research on using photolithography to replace mask evaporation to process organic compound films has been progressing. However, when processing organic compound films using photolithography, there are problems unique to light-emitting devices.

[0061] It is known that when a light emitting device is exposed to atmospheric components such as water and oxygen, its initial characteristics and reliability are affected, and it is common sense to process it in an atmosphere close to a vacuum.

[0062] Particular attention should be paid to the electron injection layer of the light-emitting device and the N-type CGL used as the intermediate layer of the light-emitting device with a tandem structure. This is because materials that have donor properties for electron transport materials, typically alkali metals, alkaline earth metals or their compounds (hereinafter also referred to as "alkali metal compounds, etc.") are usually used for the electron injection layer and N-type CGL to generate electrons. Since these alkali metal compounds, etc. are highly reactive with water or oxygen, they will deteriorate instantaneously not only when they are directly in contact with the atmosphere, but also when they are exposed to the atmosphere through multiple organic compound layers, thereby damaging the functions of the electron injection layer and the intermediate layer.

[0063] However, in the process of processing by photolithography, the surface of the EL layer is inevitably exposed to the atmosphere. Therefore, when processing by photolithography, the electron injectivity of the electron injection layer and the intermediate layer using alkali metal compounds etc. is greatly reduced. As a result, the luminous efficiency of the light-emitting device processed by photolithography including one or both of the electron injection layer and the intermediate layer using alkali metal compounds etc. is reduced or the driving voltage is increased, making it difficult to obtain good characteristics.

[0064] With respect to this problem, the electron injection layer can avoid the influence because the structure of the EL layer of the light-emitting device can be formed after photolithography processing (in the case of a so-called stacked device in which the electron injection layer is formed after the light-emitting layer).

[0065] However, in a tandem light-emitting device, when the light-emitting layer in the light-emitting unit on the cathode side is processed by photolithography, the intermediate layer of the light-emitting unit in contact with the anode side is inevitably exposed to the processing. For this reason, it is difficult to obtain good characteristics when a tandem light-emitting device using an intermediate layer with an N-type CGL using an alkali metal compound or the like is processed by photolithography.

[0066] Here, the present inventors have found that by replacing the existing N-type CGL in the intermediate layer with a layer including a metal or a metal oxide, an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and an organic compound having a second π-electron-deficient heteroaromatic ring, a tandem light-emitting device with good characteristics can be achieved even if a photolithography process that exposes the EL layer to the atmosphere is performed.

[0067] That is, by providing an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound), and a region (first region) of a metal or a metal oxide instead of the existing N-type CGL in the intermediate layer, a light-emitting device with excellent characteristics can be realized as a tandem light-emitting device even if a photolithography process that exposes the EL layer to the atmosphere is performed.

[0068] Furthermore, in one embodiment of the present invention, the LUMO energy level of the second organic compound is preferably lower than the LUMO energy level of the first organic compound, and is preferably at least 0.50 eV lower than the LUMO energy level of the first organic compound and at most 0.20 eV lower than the LUMO energy level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO energy level of the first organic compound and at most 0.25 eV lower than the LUMO energy level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO energy level of the first organic compound and at most 0.30 eV lower than the LUMO energy level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO energy level of the first organic compound and at most 0.35 eV lower than the LUMO energy level of the first organic compound, further preferably at least 0.50 eV lower than the LUMO energy level of the first organic compound and at most 0.40 eV lower than the LUMO energy level of the first organic compound.

[0069] That is, when the LUMO energy level of the first organic compound is set to "LUMO1 (eV)" and the LUMO energy level of the second organic compound is set to "LUMO2 (eV)", LUMO2 preferably satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.20.

[0070] More preferably, LUMO2 satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.25.

[0071] More preferably, LUMO2 satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.30.

[0072] More preferably, LUMO2 satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.35.

[0073] More preferably, LUMO2 satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.40.

[0074] When LUMO2 is within the above range, the light-emitting device of one embodiment of the present invention can realize a tandem light-emitting device with low driving voltage and good characteristics without undergoing a photolithography process involving exposure of the EL layer to the atmosphere. In addition, a tandem light-emitting device with good reliability can be realized.

[0075] The metal or metal oxide, the first organic compound and the second organic compound form a donor energy level (SOMO energy level or HOMO energy level) by interaction. Thus, the electron injection barrier can be reduced, and the electrons generated in the intermediate layer can be smoothly injected into the electron transport layer without using the existing N-type CGL that deteriorates significantly after the photolithography process accompanied by exposure to the atmosphere. In addition, when LUMO2 is within the above range, it is possible to interact more stably, and an intermediate layer that is not easily degraded even after the photolithography process accompanied by exposure to the atmosphere can be formed. Therefore, even after the photolithography process accompanied by exposure to the atmosphere of the EL layer, the electrons generated in the intermediate layer can be smoothly injected and transported to the adjacent electron transport layer, thereby using the photolithography process to manufacture a tandem light-emitting device in which the rise of the driving voltage is suppressed and the reliability is good.

[0076] Note that the HOMO level and LUMO level of an organic compound are generally estimated by CV (cyclic voltammetry), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, etc. When comparing values ​​of different compounds, it is preferable to use values ​​estimated by the same measurement for comparison.

[0077] In this way, by using an organic compound (first organic compound) containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring, and a metal or metal oxide as an intermediate layer, an intermediate layer resistant to oxygen and water in the atmosphere and water and chemical solutions used in the photolithography process can be formed. Thus, one embodiment of the present invention can provide an organic EL device having high moisture resistance, high water resistance, high oxygen resistance, high chemical resistance, low driving voltage, and high luminous efficiency.

[0078] In addition, as a structure including an organic compound containing a π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), an organic compound containing a second π-electron-deficient heteroaromatic ring (second organic compound), and a region (first region) of a metal or metal oxide, a structure of a mixed layer of a metal or metal oxide, a first organic compound, and a second organic compound may be selected, or a stacked structure of a layer containing a metal or metal oxide and a layer containing a first organic compound and a second organic compound may be selected. When the first region adopts a stacked structure of a layer containing a metal or metal oxide and a layer containing a first organic compound and a second organic compound, it is preferred to adopt the following structure: the layer containing a metal or metal oxide is located on the cathode side, the layer containing the first organic compound and the second organic compound is located on the anode side and is stacked in contact with each other, and the layer containing the first organic compound and the second organic compound is in contact with the light-emitting unit on the anode side.

[0079] When the first region is a mixed layer of a metal or metal oxide, a first organic compound, and a second organic compound, the number of layers can be reduced compared to a stacked structure, so that productivity is high and mass production is easy.

[0080] Note that when alkali metals or alkaline earth metals such as lithium oxide (Li2O) and their oxides are used for N-type CGLs with existing structures of tandem light-emitting devices, the light-emitting devices have good characteristics as long as they are manufactured by a vacuum continuous process (not exposed to the atmosphere). However, as described above, when manufactured through a photolithography process accompanied by exposure of the EL layer to the atmosphere, the driving voltage increases significantly compared to the light-emitting devices manufactured by a vacuum continuous process. As described above, this is because the alkali metals or alkaline earth metals and their oxides deteriorate when exposed to the atmosphere, resulting in a decrease in their donor properties.

[0081] In one embodiment of the present invention, by using an alkali metal or alkaline earth metal such as lithium oxide (Li2O) and their oxides, an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound) as an intermediate layer, a light-emitting device having the same good characteristics as a light-emitting device manufactured by a vacuum continuous process can be obtained even if the light-emitting device is manufactured through a photolithography process accompanied by exposure to the atmosphere.

[0082] This is because, as the first region, an alkali metal or alkaline earth metal and its oxide, an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound) are used, and a donor energy level (SOMO energy level or HOMO energy level) is formed due to the interaction. However, since the absolute value of the stabilization energy caused by the interaction is large and its energy level is high, the electron injection barrier from the intermediate layer to the electron transport layer is reduced even after exposure to the atmosphere, and the electrons generated in the intermediate layer can be smoothly injected and transported to the electron transport layer. Therefore, even if exposed to the atmosphere, a tandem light-emitting device with good characteristics and suppressed increase in driving voltage can be realized.

[0083] In this way, a tandem light-emitting device of one embodiment of the present invention using a first region including a metal or metal oxide, an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound) and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound) instead of the existing N-type CGL can realize a tandem light-emitting device with good characteristics even after a process of exposing the EL layer to the atmosphere. That is, by using a structure of one embodiment of the present invention, a tandem light-emitting device with good characteristics manufactured by a photolithography method including a process of exposing the EL layer to the atmosphere can be realized. Thus, a display device with ultra-high definition and good characteristics can be provided.

[0084] As described above, in the middle layer of the tandem light-emitting device, by providing a region (first region) including a metal or a metal oxide, an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound) instead of the existing N-type CGL, even the tandem light-emitting device manufactured through a process of exposure to the atmosphere can easily obtain good characteristics.

[0085] The intermediate layer of the light-emitting device of one embodiment of the present invention is a tandem light-emitting device having the first region as described above. The intermediate layer preferably includes the second region of the P-type CGL. In addition, a third region may be provided between the first region and the second region. By forming the third region, electron transfer can be smoothly performed between the first region and the second region, thereby reducing the driving voltage, reducing the interaction between the first region and the second region to improve reliability, and the like.

[0086] <<First Area>> As described above, the first region is a region disposed on the anode side of the intermediate layer, and includes a metal or metal oxide and an organic compound having a first π-deficient heteroaromatic ring with an electron-donating group (first organic compound) and an organic compound having a second π-deficient heteroaromatic ring (second organic compound). In addition, the first region is in contact with the light-emitting unit on the anode side.

[0087] <Metal or Metal Oxide> As the metal or metal oxide in the first region, a metal or metal oxide containing the following elements can be used: alkali metals such as Li (Group 1 elements); alkaline earth metals such as Mg and Ca (Group 2 elements); Group 3 elements including lanthanide elements such as Y, Eu, Yb; Group 11 elements such as Cu, Ag, Au; Group 12 elements such as Zn; rare earth metals such as Al and In (Group 13 elements); and Group 14 elements such as Sn.

[0088] In the case where the metal or metal oxide preferably uses an alkali metal or alkaline earth metal and their oxides, the donor energy level formed by the interaction with the first organic compound and the second organic compound can be a high energy level, and the electrons generated in the intermediate layer can be smoothly injected and transferred to the electron transport layer, thereby providing a light-emitting device with low driving voltage and high efficiency. In addition, metal oxides preferably use transition metals and their oxides because they are less reactive and more stable with components such as water and oxygen in the atmosphere. In the above-mentioned materials, it is preferred to use a metal or metal oxide containing an element of an odd-numbered group (Group 1, Group 3, Group 11 or Group 13) of the periodic table, because it is easy to form a donor energy level with the first organic compound and the second organic compound.

[0089] In addition, it is preferred to use a metal or metal oxide that has a low melting point and can be deposited by vacuum evaporation, thereby making it easy to form a mixed layer or stack with an organic compound. Specifically, for example, metals or metal oxides of Group 11 elements and Group 13 elements have a low melting point and are suitable for vacuum evaporation. In addition, metals or metal oxides of Group 11 elements and Group 13 elements are stable to oxygen and water in the atmosphere, so they are preferred. As a metal or metal oxide that can be deposited by vacuum evaporation, its melting point at normal pressure is preferably below 2000°C, below 1500°C, and more preferably below 1000°C, or its sublimation temperature under reduced pressure (vacuum below 1 Pa) is preferably below 1500°C, below 1000°C, and more preferably below 500°C.

[0090] Specific examples of the metal oxide include lithium, magnesium, calcium, silver, zinc, indium, and oxides thereof. Note that even metals may be oxidized to become metal oxides during a process such as deposition or release to the atmosphere.

[0091] Specifically, for example, lithium, magnesium, calcium, ytterbium, silver, zinc, aluminum, indium, or the like is preferably used as the metal material.

[0092] <First organic compound> As the first organic compound included in the first region, an organic compound having a π-electron-deficient heteroaromatic ring can be used. More preferably, an organic compound having a π-electron-deficient heteroaromatic ring having an electron-donating group is used as the first organic compound, thereby increasing the electron density of the π-electron-deficient heteroaromatic ring.

[0093] In addition, the organic compound having a π-electron-deficient heteroaromatic ring is preferably an organic compound having a heteroaromatic ring containing nitrogen, and the heteroaromatic ring containing nitrogen is preferably a pyridine ring, and particularly preferably an organic compound having a heteroaromatic ring containing two or more pyridine rings. This is because the two nitrogen atoms contained in the organic compound having a heteroaromatic ring containing two or more pyridine rings are coordinated to the metal or metal oxide, and are easy to interact with the metal or metal oxide.

[0094] In organic compounds having heteroaromatic rings containing two or more pyridine rings, nitrogen atoms are more easily coordinated to metals or metal oxides in organic compounds having bipyridine skeletons, and therefore are easily interacted with metals or metal oxides, so they are preferred. In addition, the phenanthroline ring is rigid and stable, so it is preferred. Among them, in particular, the two nitrogen atoms contained in the organic compound having 1,10-phenanthroline ring are present in a position that is easily coordinated to metals or metal oxides, so they are easily interacted with metals or metal oxides, so they are preferred.

[0095] When an electron-donating group is introduced into the 1,10-phenanthroline ring, the electron-donating group is preferably substituted at positions 4 and 7 of the 1,10-phenanthroline ring. By introducing electron-donating groups at positions 4 and 7 of the 1,10-phenanthroline ring, the electron density of the nitrogen atoms at positions 1 and 10 can be increased, thereby facilitating interaction with metals or metal oxides.

[0096] As the electron-donating group in the π-deficient heteroaromatic ring, alkyl, alkoxy, aryloxy, alkylamino, arylamino, heterocyclic amino, etc. can be cited. However, the electron-donating group preferably introduced on the π-deficient heteroaromatic ring is not limited thereto. As long as it is a base that can increase the electron density of the π-deficient heteroaromatic ring by introducing it on the π-deficient heteroaromatic ring, it can be used as an electron-donating group. In addition, the electron-donating group can also be introduced into the π-deficient heteroaromatic ring through an arylene group such as a phenylene group, and the arylene group is preferably a p-phenylene group.

[0097] Specific examples of the alkyl group that can be used as the electron-donating group include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, neopentyl, hexyl, isohexyl, sec-hexyl, tert-hexyl, neohexyl, 3-methylpentyl, 2-methylpentyl, 2-ethylbutyl, 1,2-dimethylbutyl and 2,3-dimethylbutyl.

[0098] Specific examples of the alkoxy group that can be used as the above-mentioned electron-donating group include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy, sec-pentoxy, tert-pentoxy, neopentoxy, n-hexoxy, isohexoxy, sec-hexoxy, tert-hexoxy, and neohexyloxy.

[0099] Specific examples of the aryloxy group that can be used as the electron-donating group include phenoxy, o-tolyloxy, m-tolyloxy, p-tolyloxy, mesityloxy, o-biphenyloxy, m-biphenyloxy, p-biphenyloxy, 1-naphthyloxy, 2-naphthyloxy, 2-fluorenyloxy, etc. The aryloxy group may further have a substituent, and specific examples of the substituent include alkyl, alkoxy, phenyl, etc.

[0100] Specific examples of the alkylamino group which can be used as the electron-donating group include a dimethylamino group and a diethylamino group.

[0101] Specific examples of the arylamino group that can be used as the electron-donating group include diphenylamino, bis(α-naphthyl)amino, bis(m-tolyl)amino, etc. The arylamino group may further have a substituent, and specific examples of the substituent include alkyl, alkoxy, phenyl, etc.

[0102] Specific examples of the heterocyclic amino group that can be used as the electron-donating group include groups represented by the following structural formulas (R-1) to (R-26). Note that the heterocyclic amino group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0103] [Chemical formula 1]

[0104] In addition, the group represented by the structural formula (R-1), (R-2), (R-3), (R-4), (R-5), (R-8), (R-9), (R-10), (R-12), (R-14), (R-15), (R-16), (R-17) or (R-21) is more preferred as an electron-donating group. Among them, the group represented by the structural formula (R-3) (R-4) (R-8) or (R-21) has high electron-donating properties and can further increase the electron density of the phenanthroline ring, so it is particularly preferred.

[0105] Specific examples of the electron-donating group include groups represented by the following structural formulas (R-27) and (R-28).

[0106] [Chemical formula 2]

[0107] Note that the organic compound having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound can also have both the above-mentioned electron-donating group and a substituent other than the above-mentioned group. As a specific example of a substituent other than the above-mentioned electron-donating group that can be introduced into the π-electron-deficient heteroaromatic ring, an aryl group can also be cited. As a specific example of an aryl group, phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, o-biphenyl, m-biphenyl, p-biphenyl, 1-naphthyl, 2-naphthyl, 2-fluorenyl, etc. can be cited. The aryl group can also have a substituent, and as a specific example of the substituent, an alkyl group, an alkoxy group, a phenyl group, etc. can be cited.

[0108] Structural formulae (100) to (110) show specific examples of organic compounds having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound. Note that the organic compound that can be used as the first organic compound is not limited thereto.

[0109] [Chemical formula 3]

[0110] In addition, when the negative minimum value of the electrostatic potential (ESP: Electrostatic Potential) of the first organic compound is small (the absolute value of the negative value is large), the absolute value of the stabilization energy due to the interaction with the metal or the metal oxide is large, which is preferable.

[0111] In organic compounds having π-electron-deficient heteroaromatic rings, the electrostatic potential around the heteroatoms of the π-electron-deficient heteroaromatic rings tends to become negative. By introducing electron-donating groups into the π-electron-deficient heteroaromatic rings, the electrostatic potential around the heteroatoms of the π-electron-deficient heteroaromatic rings can be further reduced (the absolute value of the negative value can be increased).

[0112] Electrostatic potential refers to the interaction energy between a positive point charge with a unit charge and the electron distribution of a molecule. In addition, the value of electrostatic potential also varies depending on the threshold value of electron density.

[0113] In order to improve the efficiency of interaction with the metal or metal oxide, the minimum value of the electrostatic potential of the first organic compound is preferably smaller than (greater in a negative direction than) the minimum value of the electrostatic potential of a π-electron-deficient heteroaromatic ring having no substituent.

[0114] Specifically, when the threshold of the electron density distribution in atomic units is 0.0004e / a0 3 (e represents elementary charge (1e=1.60218×10 -19 C), a0 represents the Bohr radius (1a0 = 5.29177 × 10 -11 m)), the minimum value of the electrostatic potential of the first organic compound is preferably -0.085E h (Eh represents the Hartree energy (1E h =27.211eV)) or less, preferably -0.090E h In addition, when the threshold of the electron density distribution in atomic units is 0.003e / a0 3 When the minimum value of the electrostatic potential of the first organic compound is preferably -0.12E h Below, more preferably -0.13E h In addition, when the threshold value of the electron density distribution in atomic units is 0.0004e / a0 3 When the minimum value of ESP of the first organic compound is preferably -0.085E h Hereinafter, it is more preferred that when the threshold value of the electron density distribution in atomic units is 0.003e / a0 3 The minimum value is -0.12E h .

[0115] The minimum values ​​of electrostatic potential (ESP) of the organic compounds represented by the above-mentioned structural formulas (100) to (107), BPhen, mPPhen2P, NBPhen, Phen, and Hid2Phen, which are organic compounds that can be used as the first organic compound, were estimated by quantum chemical calculation. The structural formulas of the organic compounds represented by the structural formulas (100) to (107), BPhen, mPPhen2P, NBPhen, Phen, and Hid2Phen are shown below.

[0116] [Chemical formula 4]

[0117] Gaussian09 was used as a quantum chemical calculation program. SGI8600 manufactured by HPE was used for calculation. The most stable structure of each organic compound in the ground state was calculated using density functional theory (DFT). 6-311G (d, p) was used as the basis function, and B3LYP was used as the functional.

[0118] Table 1 shows the analysis results of the electrostatic potential in the ground state of each organic compound. Note that the electrostatic potential refers to the interaction energy of a positive point charge with a unit charge and the electron distribution of a molecule. In addition, the value of the electrostatic potential also varies according to the threshold value of the electron density. Table 1 shows the density threshold in atomic units as 0.0004e / a. 3 or 0.003e / a0 3The electrostatic potential in the electron density distribution in atomic units at .

[0119] [Table 1]

[0120] From the table above, we can see that when the threshold of electron density distribution in atomic units is 0.0004e / a0 3 When the organic compounds represented by the structural formulas (100) to (103) and Hid2Phen have a minimum ESP of -0.085E h The following is more suitable for use as the first organic compound. In addition, when the threshold value of the electron density distribution in the atomic units is 0.003e / a0 3 When the organic compounds represented by the structural formulas (100) to (103) and Hid2Phen have a minimum ESP of -0.12E h The following are more preferably used as the first organic compound.

[0121] This is because the organic compounds represented by structural formulas (100) to (103) and Hid2Phen have electron-donating groups introduced at the 4- and 7-positions of the 1,10-phenanthroline ring, thereby providing high electron-donating properties to nitrogen at the 1- and 10-positions of the phenanthroline ring.

[0122] In addition, when the threshold of the electron density distribution in atomic units is 0.0004e / a0 3 When the organic compounds represented by the structural formula (101) and the structural formula (103) and Hid2Phen have a minimum ESP of -0.090E h In addition, when the threshold value of the electron density distribution in the atomic units is 0.003e / a0 3 When the organic compound represented by the structural formula (103) and Hid2Phen have a minimum ESP of -0.13E h The following are particularly suitable for use as the first organic compound.

[0123] In addition, when the threshold of the electron density distribution in atomic units is 0.0004e / a0 3 When the organic compound represented by the structural formula (103) and Hid2Phen have a minimum ESP of -0.090E h Below and when the threshold value of the electron density distribution in atomic units is 0.003e / a0 3The minimum ESP value is -0.13E h The following is further preferably used as the first organic compound.

[0124] In addition, when the basicity of the first organic compound is high, the hole transport property in the first region of the intermediate layer can be greatly reduced by interaction with holes, thereby realizing a light-emitting device with high efficiency and low driving voltage, which is preferred. Specifically, the acidity coefficient pKa of the first organic compound is preferably 8 or more, more preferably 10 or more, and further preferably 12 or more.

[0125] When the acidity coefficient pKa of an organic compound is unknown, the acidity coefficient pKa of each skeleton possessed by the organic compound may be investigated, and the largest acidity coefficient pKa among them may be regarded as the acidity coefficient pKa of the organic compound.

[0126] Alternatively, the acidity coefficient can be obtained by calculation. For example, the acidity coefficient pKa can be obtained by the following calculation method.

[0127] As the initial structure of the molecular structure of each molecule used as the calculation model, the most stable structure (single ground state) obtained by first-principles calculation was adopted.

[0128] As in the above first principles calculation, use Jaguar, a quantum chemical calculation software manufactured by Inc., calculates the most stable structure in the singlet ground state by density functional theory (DFT). 6-31G** is used as the basis function and B3LYP-D3 is used as the functional function. As the structure for quantum chemical calculation, Maestro GUI manufactured by , Inc., performs conformational analysis and sampling using Mixed torsional / Low-mode sampling.

[0129] In the pKa calculation, one or more atoms in each molecule are designated as basic positions, and the Macro Model is used to explore the stable structure of the protonated molecule in water, and the lowest energy conformer obtained by conformational exploration using the OPLS2005 force field is used. The pKa calculation module of Jaguar is used to optimize the structure using B3LYP / 6-31G*, and then single-point calculation is performed with cc-pVTZ(+), and the pKa value is calculated using empirical correction for functional groups. In molecules where one or more atoms are designated as basic positions, the largest value among the obtained results is used as the pKa value. The obtained pKa values ​​are shown.

[0130] The acidity coefficient pKa of 2,9hpp2Phen is 13.35, the acidity coefficient pKa of 4,7hpp2Phen is 13.42, the acidity coefficient pKa of Pyrrd-Phen is 11.23, the acidity coefficient pKa of mPPhen2P is 5.16, the acidity coefficient pKa of NBPhen is 5.59, and the acidity coefficient pKa of BPhen is 5.62.

[0131] <Estimating the Interaction between Metals and Organic Compounds Using Quantum Chemical Calculations> Here, the spin density and electrostatic potential (ESP: Electrostatic Potential) when a metal interacts with a first organic compound including a π-electron-deficient heteroaromatic ring having an electron-donating group and a second organic compound having a π-electron-deficient heteroaromatic ring are analyzed by quantum chemical calculation. Note that the calculation was performed using 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) as the first organic compound, 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr) as the second organic compound, and silver (Ag) as the metal.

[0132] As a quantum chemical calculation program, Gaussian09 is used. SGI8600 manufactured by HPE is used for calculation. Density functional theory (DFT: Density Functional Theory) is used to calculate the most stable structure of the first organic compound monomer and the second organic compound monomer in the ground state, the composite material of the first organic compound and the metal, the composite material of the second organic compound and the metal, and the most stable structure of the composite material of the first organic compound, the second organic compound and the metal in the ground state. 6-311G (d, p) and LanL2DZ are used as basis functions, and B3LYP is used as a functional. The total energy of DFT is expressed as the sum of potential energy, electrostatic energy between electrons, kinetic energy of electrons, and exchange-correlation energy including all complex interactions between electrons. In DFT, since the exchange-correlation interaction is approximated using a functional (meaning a function of a function) of a single electron potential represented by electron density, the calculation accuracy is high.

[0133] FIG. 19A to FIG. 19CThe analysis results of the spin density distribution in the ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag), the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag), and the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) are shown. The balls in the figure represent the atoms constituting the compound, and the cloud-like objects existing around the atoms represent the density value of 0.003e / a0 in the atomic unit system. 3 The spin density distribution at the time of , and indicates that the doublet ground state in the compound is localized. Note that since the ground state of the first organic compound (Pyrrd-Phen) and the ground state of the second organic compound (11mDBtBPPnfpr) are singlet ground states, no spin density distribution is observed.

[0134] When the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag) is in a double ground state, the first organic compound (Pyrrd-Phen) and the metal (Ag) interact with each other, and the metal (Ag) coordinates to the nitrogen atoms (nitrogen atoms (N) at the 1st and 10th positions) having non-shared electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) to become stable, thereby forming a composite material. Fig.19A It can be seen that part of the spins derived from the unpaired electrons of the metal (Ag) are distributed on a part of the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), especially on the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) having unshared electron pairs. However, since the interaction is weak, most of the spins are distributed on the metal (Ag).

[0135] In addition, when the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is in a double ground state, the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other, and the metal (Ag) coordinates to the nitrogen atom (N) having a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to become stable, thereby forming a composite material. Thus, according to Fig.19B It is known that part of the spins derived from the unpaired electrons of the metal (Ag) are distributed on a part of the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr), especially on the nitrogen atom (N) having an unshared electron pair. However, since the interaction is weak, most of the spins are distributed on the metal (Ag).

[0136] On the other hand, in one embodiment of the present invention, when the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is in a double ground state, the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other, and the metal (Ag) coordinates to the nitrogen atom (nitrogen atom (N) at the 1st and 10th positions) having a non-shared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atom (N) having a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to become stable, thereby forming a composite material. Thus, according to Fig.19C It can be seen that the spins of the unpaired electrons contained in the metal (Ag) are locally distributed on the second organic compound (11mDBtBPPnfpr). In addition, the spin density distribution of the metal (Ag) is not observed. It can be seen that due to the interaction between the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and the metal (Ag), the second organic compound (11mDBtBPPnfpr) is in a radical anion state.

[0137] then, Fig. 20A , Fig. 20B , Fig.21A , Fig.21B and Fig. 21C The analysis results of the electrostatic potential diagram in the ground state of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), the composite material of the first organic compound (Pyrrd-Phen) and metal (Ag), the composite material of the second organic compound (11mDBtBPPnfpr) and metal (Ag), and the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and metal (Ag) are shown. The balls in the figure represent atoms constituting the compound, and the cloud-like objects existing around the atoms represent that the density value is 0.0004e / a0 in the atomic unit system. 3 Electrostatic potential in the electron density distribution when . Electrostatic potential is the interaction energy between a positive point charge with unit charge and the electron distribution of a molecule. Electrostatic potential maps use colors to represent the electrostatic potential in the equal electron density surface. In the electrostatic potential map, red and blue are used to represent areas with negative and positive electrostatic potential, respectively. Atoms in areas with negative electrostatic potential have negative charges, and atoms in areas with positive electrostatic potential have positive charges. Note that due to Fig. 20A and Fig. 20B as well as FIG. 21A to FIG. 21C It is a grayscale image, so in order to indicate the area with negative electrostatic potential and the area with positive electrostatic potential, the part represented by dark red (i.e., the area with negative electrostatic potential) is surrounded by a thick dotted line, and the part represented by dark blue (i.e., the area with positive electrostatic potential) is surrounded by a thin dotted line.

[0138] like Fig. 20A As shown, it can be seen that in the singlet ground state of the first organic compound (Pyrrd-Phen), the electrostatic potential around the nitrogen atom (nitrogen atom (N) at position 1 and position 10) having a non-shared electron pair in the 1,10-phenanthroline ring is negative. In addition, the Mulliken partial charge of the N atom is a negative value in the atomic unit system, that is, -0.29e. Therefore, it can be seen that the N atom has a negative partial charge.

[0139] like Fig. 20B As shown, it can be seen that in the singlet ground state of the second organic compound (11mDBtBPPnfpr), the electrostatic potential around the nitrogen atom (N) having a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring is negative. In addition, the Mulliken partial charge of the N atom is negative in the atomic unit system, that is, -0.31e. Therefore, it can be seen that the N atom has a negative partial charge.

[0140] When the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag) is in a double ground state, the first organic compound (Pyrrd-Phen) and the metal (Ag) interact with each other, and the metal (Ag) coordinates to the nitrogen atoms (nitrogen atoms (N) at the 1st and 10th positions) having non-shared electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) to become stable, thereby forming a composite material. As a result, Fig.21A As shown, it can be seen that the electrostatic potential around the nitrogen atom (nitrogen atom (N) at position 1 and position 10) and the metal (Ag) in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) is negative. In addition, the Mulliken partial charge of each N atom is negative in the atomic unit system, that is, -0.37e, and the Mulliken partial charge of the metal (Ag) is negative in the atomic unit system, that is, -0.18e. It can be seen that the N atom and the Ag atom have negative partial charges.

[0141] When the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is in a double ground state, the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other, and the metal (Ag) coordinates to the nitrogen atom (N) having a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to become stable, thereby forming a composite material. As a result, as Fig.21B As shown, it can be seen that the electrostatic potential around the nitrogen atom (N) and the metal (Ag) having a non-shared electron pair in the phenanthro[9', 10': 4, 5] furano[2, 3-b] pyrazine ring of the second organic compound (11mDBtBPPnfpr) is negative. In addition, the Mulliken partial charge of each N atom is a negative value in the atomic unit system, that is, -0.38e, and the Mulliken partial charge of the metal (Ag) is a negative value in the atomic unit system, that is, -0.09e. Therefore, it can be seen that the N atom and the Ag atom have negative partial charges.

[0142] On the other hand, in one embodiment of the present invention, when the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is in a double ground state, the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other, and the metal (Ag) coordinates to the nitrogen atom (nitrogen atom (N) at the 1st and 10th positions) having a non-shared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atom (N) having a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to become stable, thereby forming a composite material. As a result, as Fig. 21C As shown, it can be seen that the positive electrostatic potential is mainly distributed on the metal (Ag) and the first organic compound (Pyrrd-Phen), and the negative electrostatic potential is mainly distributed on the second organic compound (11mDBtBPPnfpr). In addition, it can be seen that the electrostatic potential around the nitrogen atom (N) with a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) is negative, while the electrostatic potential around the metal (Ag) is positive. In addition, the Mulliken partial charge of the N atom is a negative value in the atomic unit system, that is, -0.62e, while the Mulliken partial charge of the metal (Ag) is a positive value in the atomic unit system, that is, 0.37e. It can be seen that the charge of the Ag atom is distributed on the N atom.

[0143] It can be seen that the following combination is formed: a donor energy level is formed by the interaction between the first organic compound having an electron-donating group and a π-electron-deficient heteroaromatic ring and the metal, and the second organic compound having a π-electron-deficient heteroaromatic ring acts as an electron donor. In one embodiment of the present invention, by using a material having this combination for an intermediate layer, an intermediate layer having good electron injection properties and resistance to oxygen and water in the atmosphere and water and chemical solutions used in the process in lithography can be formed, thereby realizing a light-emitting device with reduced driving voltage and high luminous efficiency.

[0144] <Estimation of SOMO or HOMO energy levels in the interaction between metals and organic compounds using quantum chemical calculations> Next, quantum chemical calculations are used to estimate the stability energy and the SOMO energy level or HOMO energy level formed when the metal interacts with the first organic compound containing a π-electron-deficient heteroaromatic ring having an electron-donating group and the second organic compound containing a π-electron-deficient heteroaromatic ring.

[0145] As a quantum chemical calculation program, Gaussian09 is used. SGI8600 manufactured by HPE is used for calculation. First, the most stable structures of the first organic compound, the second organic compound and the metal in the ground state, as well as the composite material of the first organic compound and the metal, the composite material of the second organic compound and the metal, and the composite material of the first organic compound, the second organic compound and the metal in the ground state are calculated using density functional theory (DFT). 6-311G (d, p) and LanL2DZ are used as basis functions, and B3LYP is used as a functional. Next, the total energy of the composite material of the organic compound and the metal is subtracted from the sum of the total energy of the organic compound monomer and the total energy of the metal monomer to calculate the stability energy. That is, (stable energy) = (total energy of the composite material of the organic compound and the metal) - (total energy of the organic compound monomer) - (total energy of the metal monomer).

[0146] The following table shows that 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as Pyrrd-Phen) is the first organic compound, 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), 9-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9mDBtBPNfpr), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofuran The results are calculated using indium (In) as the metal, and using 2-[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), and 2-[4-(2-naphthyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)Tzn) as the second organic compound. Note that the HOMO and SOMO energy levels in the table are calculated values ​​and may differ from the actual measured values.

[0147] [Table 2] HOMO level (eV) Pyrrd-Phen -5.65 NBPhen -5.74 9mDBtBPNfpr -5.96 8mpTP4mDBtPBfpm -5.94 mPn-mDMePyPTzn -5.96 βNP-SFx(4)Tzn -5.93

[0148] [Table 3] Stability Energy(eV) SOMO level (eV) NBPhen+In -1.5 -3.28 9mDBtBPNfpr+In -0.8 -3.64 8mpTP4mDBtPBfpm+In -0.8 -3.69 mPn-mDMePyPTzn+In -0.6 -3.08 βNP-SFx(4)Tzn+In -0.7 -3.51

[0149] [Table 4] Stability Energy(eV) SOMO level (eV) Pyrrd-Phen+NBPhen+In -1.3 -3.02 Pyrrd-Phen+9mDBtBPNfpr+In -1.9 -2.78 Pyrrd-Phen+8mpTP4mDBtPBfpm+In -1.9 -2.86 Pyrrd-Phen+mPn-mDMePyPTzn+In -1.9 -2.99 Pyrrd-Phen+βNP-SFx(4)Tzn+In -1.8 -2.86

[0150] As can be seen from the above table, the stability energy of the composite material of the two materials of the metal (In) and the second organic compound (NBPhen, 9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) is negative. This means that when the organic compound and the metal are mixed, the interaction between them is more stable in energy than the case where the organic compound and the metal do not interact. In addition, the SOMO energy level formed at this time is higher than the HOMO energy level of the first organic compound (Pyrrd-Phen) and the second organic compound (NBPhen, 9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn).

[0151] In addition, compared with the composite material of a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) having a π-electron-deficient heteroaromatic ring different from the 1,10-phenanthroline ring and a metal (In), the absolute value of the stabilization energy of the composite material of a second organic compound (NBPhen) having a π-electron-deficient heteroaromatic ring that is the same as the Pyrrd-Phen of the first organic compound and a metal (In) is larger and more stabilized, and the formed SOMO energy level is also higher.

[0152] Here, compared with the composite material of two materials consisting of a metal (In) and a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn), the composite material of three materials consisting of a metal (In), a first organic compound (Pyrrd-Phen) and a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) according to one embodiment of the present invention has a larger absolute value of stabilization energy and is more stabilized. In addition, the SOMO energy level formed at this time is higher than the HOMO energy level of each of the first organic compound (Pyrrd-Phen) and the second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn). The higher the SOMO energy level, the better the electron injection property, so it is preferred.

[0153] At this time, compared with the composite material of the second organic compound (NBPhen) having the same 1,10-phenanthroline ring as Pyrrd-Phen as a π-electron-deficient heteroaromatic ring, the first organic compound (Pyrrd-Phen) and the metal (In), the composite material of the second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) having a π-electron-deficient heteroaromatic ring different from the 1,10-phenanthroline ring contained in Pyrrd-Phen of the first organic compound, the first organic compound (Pyrrd-Phen) and the metal (In) has a large absolute value of the stabilization energy and is stabilized, and the formed SOMO energy level is also higher.

[0154] In this way, when an organic compound comprising a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound) and a metal interact to form a composite material, the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are preferably different rings, thereby improving stability and electron injection properties.

[0155] In addition, as shown in the above table, the absolute value of the stability energy of the composite material of the metal, the first organic compound and the second organic compound is large and more stabilized, so it is preferred. In addition, the SOMO energy level formed at this time is higher than the HOMO energy level of each of the first organic compound and the second organic compound. The higher the SOMO energy level, the better the electron injection property, so it is preferred. In addition, since a high SOMO energy level is formed by using a metal that is stable in the atmosphere such as silver or indium without using an alkali metal compound, an intermediate layer with excellent stability and electron injection property can be formed.

[0156] <Second organic compound> The first region of the intermediate layer further comprises a second organic compound having a π-electron-deficient heteroaromatic ring in addition to the metal or metal oxide and the first organic compound. By including the second organic compound, it is possible to achieve improved heat resistance and improved electron transport properties. In one embodiment of the present invention, when the π-electron-deficient heteroaromatic ring possessed by the first organic compound is a first π-electron-deficient heteroaromatic ring and the π-electron-deficient heteroaromatic ring possessed by the second organic compound is a second π-electron-deficient heteroaromatic ring, the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are preferably different rings.

[0157] In addition, the second π-electron-deficient heteroaromatic ring is preferably a heteroaromatic ring having an azole skeleton (imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), a heteroaromatic ring having a pyridine skeleton, a heteroaromatic ring having a diazine skeleton and a heteroaromatic ring having a triazine skeleton, etc., and is particularly preferably a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring), or a triazine ring, which is electrochemically stable and has high electron transport properties.

[0158] Note that the second π-electron-deficient heteroaromatic ring may have a condensed ring structure.

[0159] In addition, in one embodiment of the present invention, the LUMO energy level of the second organic compound is preferably lower than the LUMO energy level of the first organic compound, and is preferably at least 0.50 eV lower than the LUMO energy level of the first organic compound and at most 0.20 eV lower than the LUMO energy level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO energy level of the first organic compound and at most 0.25 eV lower than the LUMO energy level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO energy level of the first organic compound and at most 0.30 eV lower than the LUMO energy level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO energy level of the first organic compound and at most 0.35 eV lower than the LUMO energy level of the first organic compound, further preferably at least 0.50 eV lower than the LUMO energy level of the first organic compound and at most 0.40 eV lower than the LUMO energy level of the first organic compound.

[0160] That is, when the LUMO energy level of the first organic compound is set to "LUMO1 (eV)" and the LUMO energy level of the second organic compound is set to "LUMO2 (eV)", LUMO2 preferably satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.20.

[0161] More preferably, LUMO2 satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.25.

[0162] More preferably, LUMO2 satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.30.

[0163] More preferably, LUMO2 satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.35.

[0164] More preferably, LUMO2 satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.40.

[0165] When LUMO2 is within the above range, the light-emitting device of one embodiment of the present invention can realize a tandem light-emitting device with low driving voltage and good characteristics without going through a photolithography process involving exposure of the EL layer to the atmosphere. In addition, a tandem light-emitting device with good reliability can be realized.

[0166] As the second organic compound, an organic compound having an electron transport property can be used. As the organic compound having an electron transport property, it is preferable to use an organic compound having an electron mobility of 1×10 - 7 cm2 / Vs or more, it is more preferable to use the material having an electron mobility of 1×10 -6 cm 2 In addition, any substance other than the above may be used as long as it has a higher electron-transporting property than a hole-transporting property.

[0167] Specific examples of organic compounds having electron transport properties include 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- Organic compounds having an azole skeleton such as 4-(dibenzothiophene-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4′-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN), 4,7-diphenyl-2,9-bis[4-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl]-1,10-phenanthroline (abbreviation: DBimBphen), 2-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq -II), 2-[3′-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mDBTBPDBq-II), 2-[3′-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mCzBPDBq), 2-[4′-(9-phenyl-9H-carbazole-3-yl)-3,1′-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as: 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl)phenyl]di Benzo[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-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophene-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-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-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophene-4-yl)phenyl]benzofurano[2,3-b]pyrazine (abbreviation: 3,8mDB tP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as: 4,8mDBtP2Bfpm), 8-[3′-(dibenzothiophen-4-yl)1,1′-biphenyl-3-yl]naphtho[1′,2′:4,5]furano[3,2-d]pyrimidine (abbreviated as: 8mDBtBPNfpm), 8-[(2,2′-binaphthyl)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as: 8(βN2)-4mDBtPBfpm), 2,2′-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as: 2,6(P-Bqn)2Py), 2,2′-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviated as 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviated as 6mBP-4Cz2PPm), 2,6-bis(4-naphthylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviated as 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviated as 6BP-4Cz2PPm), 7-[4-(

[0013] organic compounds having a dioxazine skeleton such as 2-( ...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[b]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-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3 , 5-triazine-2-yl)phenyl]-9′-phenyl-2,3′-bi-9H-carbazole (abbreviated as: mPCCzPTzn-02), 2-[3′-(9,9-dimethyl-9H-fluorene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviated as: mINc(II)PTzn), 2-{3-[3-(dibenzothiophene-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as: 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-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-phenylindolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3′-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1′:4′,1″-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviated as mBP-TPDBfTzn), 2-[4-(2-naphthyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9′-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviated as βNP-SFx(4)Tzn), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-Triazine (abbreviation: mSiTrz) and other organic compounds having a triazine skeleton.

[0168] Among the above materials, ZADN, mSiTrz, mPn-mDMePyPTzn, 8mpTP-4mDBtPBfpm, 11mDBtBPPnfpr, and βNP-SFx(4)Tzn have suitable LUMO energy levels and are therefore preferred as the second organic compound. By using this organic compound, even a light-emitting device obtained after a process in which the EL layer is exposed to the atmosphere can easily provide a tandem light-emitting device with good characteristics for suppressing the increase in driving voltage.

[0169] The second organic compound preferably has a carbon number of 25 to 100. By adopting such a carbon number, an organic compound with good sublimation properties can be realized, thereby suppressing thermal decomposition of the organic compound during vacuum deposition, and achieving good material utilization efficiency.

[0170] The second organic compound preferably has a glass transition temperature Tg of 100° C. or higher. This allows the intermediate layer to have high heat resistance and not be easily crystallized. This prevents the organic compound layer from being easily crystallized even when part of the organic compound layer is processed by photolithography.

[0171] In addition, as the second organic compound, an organic compound having a pKa of less than 4 can be used. This can reduce the solubility of the second organic compound in water, thereby improving the resistance to water and chemical solutions used in the process in the lithography technology.

[0172] Compared with the solubility of an organic compound having an acidity coefficient pKa of 4 or more in water, the solubility of an organic compound having an acidity coefficient pKa of less than 4 in water is low. In addition, when an organic compound having an acidity coefficient pKa of 4 or more is used as the second organic compound, the water resistance of the intermediate layer can be improved. In addition, defects such as the intermediate layer peeling off from other layers in the manufacturing process can be suppressed. Thus, the occurrence of defects that cause defects in the light-emitting device can be suppressed.

[0173] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTzn-02, BP-BPIcz(II)Tzn, etc. can be used for the second organic compound.

[0174] Note that the pKa of 4,8mDBtP2Bfpm is 0.60. The pKa of 11mDBtBPPnfpr is -1.85. When the pKa of an organic compound is unknown, the pKa of each skeleton of the organic compound is investigated, and the largest pKa among them can be regarded as the pKa of the organic compound.

[0175] In addition, for example, the polarization term δp of the solubility parameter δ can be 4.0 MPa 0.5 The following organic compounds are used as the second organic compound. For example, the polarization term δp with the solubility parameter δ is greater than 4.0 MPa 0.5 Compared with the solubility of organic compounds in water, the polarization term δp is 4.0MPa 0.5 The following organic compounds have low solubility in water. In addition, the polarization term δp is greater than 4.0 MPa. 0.5 Compared with the case where an organic compound of is used as the second organic compound, when the polarization term δp is 4.0 MPa 0.5 When the following organic compounds are used as the second organic compound, the water resistance of the intermediate layer can be improved. In addition, the occurrence of defects such as the intermediate layer peeling off from other layers during the photolithography process can be suppressed. Thus, the occurrence of defects that cause defects in the light-emitting device can be suppressed.

[0176] Japanese Patent Application Publication No. 2017-173056 states that the polarization term δp of the solubility parameter δp of water is 16.0 MPa. 0.5 .

[0177] The larger the difference between the polarization term δp of the solubility parameter δ of the organic compound and the polarization term δp of water as a solvent, the lower its solubility in water is, so it is preferred. Therefore, it is preferred to have a solubility parameter δ of 4.0 MPa. 0.5 The following organic compounds having polarization terms δp are used for the second organic compound.

[0178] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTzn-02, BP-BPIcz(II)Tzn may be used for the second organic compound.

[0179] Note that the polarization term δp of the solubility parameter δ of 8BP-4mDBtPBfpm is 3.5 MPa 0.5 , the polarization term δp of the solubility parameter δ of 4,8mDBtP2Bfpm is 3.4MPa 0.5, the polarization term δp of the solubility parameter δ of 6BP-4Cz2PPm is 3.4MPa 0.5 , the polarization term δp of the solubility parameter δ of 2mDBTBPDBq-II is 3.2MPa 0.5 , the polarization term δp of the solubility parameter δ of 9mDBtBPNfpr is 3.8MPa 0.5 , the polarization term δp of the solubility parameter δ of 11mDBtBPPnfpr is 3.1MPa 0.5 , the polarization term δp of the solubility parameter δ of mPCCzPTzn-02 is 3.5MPa 0.5 , the polarization term δp of the solubility parameter δ of BP-BPIcz(II)Tzn is 3.2MPa 0.5 .

[0180] Note that the polarization term δp of the solubility parameter δ is calculated by referring to the following calculation method.

[0181] Used as a classical molecular dynamics calculation software Desmond manufactured by Inc. In addition, OPLS2005 force field was used. The calculation was performed using Apollo6500 manufactured by Hewlett Packard Enterprise (HPE).

[0182] As a calculation model, a standard unit with about 32 molecules is used. As the initial structure of the molecular structure in each compound, the most stable structure (single ground state) obtained by first-principles calculation and the structure with the energy of the approximate most stable structure are mixed at the same ratio, and the molecules are irregularly configured in a way that the molecules do not collide. Then, the structure is irregularly migrated and rotated by using the Monte Carlo simulated annealing of OPLS2005 as a force field, thereby migrating the molecules. Furthermore, the molecules are migrated to the center of the standard unit in a way that maximizes their density, which is used as the initial configuration.

[0183] As the first principle calculation, the quantum chemical calculation software Jaguar was used to calculate the most stable structure in the single ground state by density functional theory (DFT). 6-31G** was used as the basis function and B3LYP-D3 was used as the functional function. Sampling was performed by performing conformational analysis using Mixed torsional / Low-mode sampling using Maestro GUI manufactured by Inc. Calculations were performed using Apollo 6500 manufactured by Hewlett Packard Enterprise (HPE).

[0184] The above initial configuration is subjected to Brownian motion simulation, followed by NVT ensemble, and then NPT ensemble calculation is performed at 1 atm and 300 K with a relaxation time (30 ns) sufficiently longer than the time interval (2 fs) for reproducing molecular vibrations, thereby calculating the amorphous solid. The solubility parameter δ of the obtained amorphous solid is defined by the following formula.

[0185] [Formula 1]

[0186] Here, ΔHv represents the heat of vaporization, which is the value obtained by subtracting the total energy of each molecule averaged in the molecular dynamics calculation from the energy of the standard unit, Vm represents the molar volume, R represents the gas constant, and T represents the temperature. The solubility parameter tends to decrease as the difference between the substance used as the solvent and the substance used as the solute increases.

[0187] In addition, the solubility parameter δ can be divided into a diffusion term δd and a polarization term δp. The van der Waals interaction has an influence on the diffusion term δd, and the electrostatic interaction has an influence on the polarization term δp. In particular, the electrostatic interaction generated between the dipoles of the solute and the water molecule has a great influence on the solubility of the solute in water. In fact, the solubility in water of the organic compound that can be used as the second organic compound shows a good correlation with the polarization term δp of the solubility parameter δ obtained by calculation.

[0188] Note that the LUMO energy level of the second organic compound is preferably lower than the LUMO energy level of the first organic compound. Thus, electrons can be easily supplied to the second organic compound from the donor energy level formed by the first organic compound and the metal or metal oxide. In addition, the second organic compound preferably has electron transport properties, and for this reason, the LUMO energy level of the second organic compound is preferably lower than the LUMO energy level of the first organic compound.

[0189] The LUMO level of the second organic compound is preferably -3.0 eV to -2.0 eV, more preferably -3.0 eV to -2.5 eV. The LUMO level of the first organic compound is preferably -3.0 eV to -2.0 eV, more preferably -2.7 eV to -2.0 eV.

[0190] This makes it easy to supply electrons from the donor level formed by the first organic compound and the metal or metal oxide to the second organic compound. Also, this makes it easy to transfer electrons in the second organic compound.

[0191] Furthermore, since the first region contains the second organic compound in addition to the metal or metal oxide and the first organic compound, the materials can interact with each other efficiently, which can be confirmed by measuring the spin density using the electron spin resonance method (ESR).

[0192] For example, the spin density measured by ESR of a film comprising a metal or metal oxide and a first organic compound is preferably higher than the spin density measured by ESR of a film comprising a metal or metal oxide and a second organic compound. In addition, the spin density measured by ESR of a film comprising a metal or metal oxide, a first organic compound, and a second organic compound is preferably higher than the spin density measured by ESR of a film comprising any two materials of the metal or metal oxide, the first organic compound, and the second organic compound, in which case it can be confirmed that the materials efficiently interact with each other.

[0193] More specifically, in the film containing the metal or metal oxide and the first organic compound, for example, the spin density of the signal observed at a g value of about 2.00 by the electron spin resonance method is preferably 5×10 16 spins / cm 3 More preferably, 1×10 17 spins / cm 3 In this case, it can be confirmed that the materials in the layer containing the metal or metal oxide and the first organic compound interact efficiently. Alternatively, in the film containing the metal or metal oxide, the first organic compound and the second organic compound, for example, the spin density of the signal observed at a g value of 2.00 by the electron spin resonance method is preferably 5×10 16 spins / cm 3 More preferably, 1×10 17 spins / cm 3 In this case, it can be confirmed that the layer containing the metal or metal oxide, the first organic compound and the second organic compound interacts more efficiently than the layer containing only two of the above materials. At this time, in the mixed film containing the metal or metal oxide and the second organic compound, for example, the spin density of the signal observed by the electron spin resonance method at a g value of 2.00 is 2×10 16 spins / cm 3 Next, in a mixed film containing the first organic compound and the second organic compound, for example, the spin density due to a signal observed at a g value of 2.00 by an electron spin resonance method is 2×10 16 spins / cm 3 the following.

[0194] In the first region, the molar ratio of the metal or metal oxide to the first organic compound (or the sum of the first organic compound and the second organic compound) is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and further preferably 0.5 or more and 2 or less. Alternatively, the volume ratio is preferably 0.01 or more and 0.3 or less, more preferably 0.02 or more and 0.2 or less, and further preferably 0.05 or more and 0.1 or less. By including a first region containing a metal or metal oxide and a first organic compound (or a first organic compound and a second organic compound) in the above ratio, an intermediate layer having good electron injection properties can be provided. In addition, the second organic compound may not be used, but in the case of using the second organic compound, the volume ratio of the first organic compound to the second organic compound is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and further preferably 0.5 or more and 2 or less. By mixing the first organic compound and the second organic compound at this ratio, an intermediate layer having good electron transport properties can be provided. In addition, by using an organic compound with good thermal properties of high Tg as the second organic compound, a light-emitting device with high reliability can be provided.

[0195] In addition, the thickness of the first region is preferably 2 nm or more and 20 nm or less, more preferably 5 nm or more and 10 nm or less. When the first region adopts a laminated structure of a layer of a metal or metal oxide and a layer containing a first organic compound, the layer of the metal or metal oxide is preferably 0.1 nm or more and 5 nm or less, more preferably 0.2 nm or more and 2 nm or less. In addition, when the first region adopts a laminated structure of a layer of a metal or metal oxide and a layer containing a first organic compound, the thickness of the layer containing the first organic compound is preferably 2 nm or more and 20 nm or less, more preferably 5 nm or more and 10 nm or less.

[0196] <<Second Area>> The second region is a P-type CGL, and is preferably formed using a composite material including an organic compound having a hole-transporting property (third organic compound) and a substance having an electron-accepting property for the organic compound having a hole-transporting property.

[0197] As a substance having electron acceptor properties for an organic compound having hole transport properties, an organic compound having an electron withdrawing group (halogen, cyano, etc.) can be used, and an organic compound having at least one of a halogen and a cyano group is preferably used. Specifically, 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), 2-(7-dicyano-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile, etc. can be cited. In particular, compounds such as HAT-CN in which an electron-withdrawing group is bonded to a fused aromatic ring having a plurality of heteroatoms are thermally stable and therefore are preferred. In addition, [3]radialene derivatives including an electron-withdrawing group (especially a halogen group such as a fluorine group or a cyano group) are particularly preferred because they have a very high electron accepting property. Specifically, examples thereof include: α, α', α"-1,2,3-cyclopropane trimethylene tris[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α, α', α"-1,2,3-cyclopropane trimethylene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], α, α', α"-1,2,3-cyclopropane trimethylene tris[2,3,4,5,6-pentafluorophenylacetonitrile], and the like.

[0198] In addition, in addition to the above-mentioned organic compounds, substances having electron acceptor properties may also use transition metals such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, or their oxides. In this case, it can also be said that one embodiment of the present invention is a light-emitting device in which the P-type CGL and the N-type CGL use different metals or metal oxides from each other in the intermediate layer. Alternatively, it can also be said that the P-type CGL and the N-type CGL are light-emitting devices that contain different metals or metal oxides and organic compounds from each other. Since metals or metal oxides are relatively stable, when metals or metal oxides are used as both the P-type CGL and the N-type CGL, a tandem light-emitting device including an intermediate layer that is stable to oxygen and water in the atmosphere and to water and chemical solutions in the manufacturing process can be manufactured.

[0199] As the organic compound with hole transport property used in the composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, high molecular weight compounds (oligomers, dendrimers, polymers, etc.) can be used. As the organic compound with hole transport property used in the composite material, it is preferred to use an organic compound with a hole mobility of 1×10 -6 cm 2 / Vs or more organic compound. The organic compound with hole transport properties used in the composite material is preferably a compound containing a fused aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the fused aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, etc. are preferred. In addition, as the π-electron-rich heteroaromatic ring, a fused aromatic ring containing at least one of a pyrrole skeleton, a furan skeleton and a thiophene skeleton is preferred, and specifically a carbazole ring, a dibenzothiophene ring or a ring in which these rings are also fused with an aromatic ring or a heteroaromatic ring is preferred.

[0200] Such an organic compound having hole transport properties preferably has any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, it may be an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine containing a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to nitrogen of the amine through an arylene group. Note that when these organic compounds having hole transport properties are substances containing N, N-bis(4-biphenyl)amino groups, a light-emitting device with a long life can be manufactured, so it is preferred.

[0201] Specific examples of the organic compound having a hole transport property include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BBABnf), 4,4′-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4″-phenyltriphenylamine (abbreviated as BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviated as BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1 ,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-benzidine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4′,4″-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4′,4″-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4′- diphenyl-4″-(6;1′-binaphthyl-2-yl)triphenylamine (abbreviated as: BBAαNβNB), 4,4′-diphenyl-4″-(7;1′-binaphthyl-2-yl)triphenylamine (abbreviated as: BBAαNβNB-03), 4,4′-diphenyl-4″-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviated as: BBAPβNB-03), 4,4′-diphenyl-4″-(6;2′-binaphthyl-2-yl)triphenylamine (abbreviated as: BBA(βN2)B), 4,4′-diphenyl-4″-(7;2′-binaphthyl-2-yl)triphenylamine (abbreviated as: BBA(βN2)B-03), 4,4′-diphenyl-4″-(4;2′-binaphthyl- 1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4′-diphenyl-4″-(5;2′-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenyl)-4′-(2-naphthyl)-4″-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenyl)-4′-[4-(2-naphthyl)phenyl]-4″-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenyl)-4′-[4-(2-naphthyl)phenyl]-4″-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4′-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4′-Bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4′-diphenyl-4″-[4′-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4′-[4-(3-phenyl-9H-carbazol-9-yl)phenyl]tri(biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4′-(carbazol-9-yl)biphenyl-4-yl]-4′-(2-naphthyl)-4″-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9′-spirobi[9H-fluorene]-2-amine (abbreviation: PCBN BSF), N,N-bis(biphenyl-4-yl)-9,9′-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9′-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9′-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluorene-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-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4′-diphenyl-4″-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4′-(9-phenyl-9H-carbazole-3-yl)triphenylamine ( Abbreviation: PCBANB), 4,4′-di(1-naphthyl)-4″-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9′-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9′-spirobi-9H-fluorene-4-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9′-spirodi-9H-fluorene-3-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9′-spirodi-9H-fluorene-2-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9′-spirodi-9H-fluorene-1-amine, etc.

[0202] In addition, as materials with hole transport properties, as other aromatic amine compounds, 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), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can also be used.

[0203] In addition, the electron acceptor material of the P-type CGL preferably has electron acceptor properties. In addition, the electron acceptor material preferably has electron acceptor properties for organic compounds having hole transport properties. Since the electron acceptor material has electron acceptor properties, charge separation occurs in the P-type CGL and can be used as a charge generation layer, so it can be used as an intermediate layer of a tandem structure. In addition, it is preferred that a signal can be observed using the electron spin resonance method in the P-type CGL. For example, the spin density of the signal observed near the g value of 2.00 is preferably 1×10 17 spins / cm 3 More preferably, 1×10 18 spins / cm 3 More preferably, 1×10 19 spins / cm 3 above.

[0204] <<Third Area>> In addition, a third region may be provided between the first region and the second region of the intermediate layer.

[0205] The third region contains a substance having an electron transport property and has the function of smoothly transferring electrons between the first region and the second region to reduce the driving voltage and has the function of reducing the interaction between the first region and the second region to improve the reliability.

[0206] The LUMO level of the electron-transporting substance in the third region is preferably between the LUMO level of the acceptor substance in the second region and the LUMO level of the organic compound in the layer in contact with the intermediate layer in the light-emitting unit on the anode side.

[0207] In addition, as the specific energy level of the LUMO energy level of the substance with electron transport properties used in the third region, it is preferably above -5.0 eV, more preferably above -5.0 eV and below -3.0 eV, more preferably above -4.30 eV and below -3.00 eV, more preferably above -4.30 eV and below -3.30 eV, thereby suppressing the increase in driving voltage. In addition, as the substance with electron transport properties used in the third region, it is preferred to use a phthalocyanine material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0208] As the electron-transporting substance used in the third region, specifically, diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA-F6), 3,4,9,10-perylenetetracarboxylic acid diimide (abbreviation: PTCDI), 3,4,9,10-perylenetetracarboxylic acid-bis-benzimidazole (abbreviation: PTCBI) and other perylenetetracarboxylic acid derivatives, (C60-Ih)[5,6]fullerene (abbreviation: C60), (C70-D5h)[5,6]fullerene (abbreviation: C70) can be used. In addition, a compound including a heterocyclic cyclophenane skeleton containing a heterocyclic ring can be used. As such a compound, for example, a phthalocyanine compound such as phthalocyanine (abbreviation: H2Pc) can be used. In addition, metal phthalocyanines containing copper, zinc, cobalt, iron, chromium, nickel, etc., such as copper phthalocyanine (abbreviation: CuPc), zinc phthalocyanine (abbreviation: ZnPc), cobalt phthalocyanine (abbreviation: CoPc), iron phthalocyanine (abbreviation: FePc), tin phthalocyanine (abbreviation: SnPc), tin phthalocyanine oxide (abbreviation: SnOPc), titanium phthalocyanine oxide (abbreviation: TiOPc), vanadium phthalocyanine oxide (abbreviation: VOPc) and their derivatives can be used. In particular, phthalocyanine metal complexes such as copper phthalocyanine or zinc phthalocyanine or 2,3,8,9,14,15-hexafluorobisquinoxalino[2,3-a:2',3'-c]phenazine are preferably used.

[0209] In addition, the thickness of the third region is preferably greater than or equal to 1 nm and less than or equal to 10 nm, and more preferably greater than or equal to 2 nm and less than or equal to 5 nm.

[0210] The light-emitting device of one embodiment of the present invention having the above-described structure can have excellent characteristics even if it is exposed to the atmosphere before the second electrode is formed or is processed by photolithography involving exposure to the atmosphere.

[0211] Implementation Method 2 In this embodiment, a light-emitting device which is one embodiment of the present invention is described in detail.

[0212] Figure 11 is a schematic diagram of a light-emitting device 130 according to one embodiment of the present invention. In the light-emitting device 130, a first electrode 101 is provided on an insulator 100, and an organic compound layer 103 is included between the first electrode 101 and the second electrode 102. As described in Embodiment 1, the organic compound layer 103 includes a plurality of light-emitting units ( Figure 1 The first light-emitting unit 501 and the second light-emitting unit 502) and the intermediate layer 116.

[0213] The first light-emitting unit 501 includes at least a first light-emitting layer 113_1, and the second light-emitting unit 502 includes at least a second light-emitting layer 113_2. The first light-emitting layer 113_1 and the second light-emitting layer 113_2 are layers containing a light-emitting substance, and emit light when a voltage is applied between the first electrode 101 and the second electrode 102.

[0214] like Figure 1 As shown, the first light-emitting unit 501 preferably includes functional layers such as a hole injection layer 111, a first hole transport layer 112_1, and a first electron transport layer 114_1 in addition to the above-mentioned layers. In addition, the first light-emitting unit 501 may also include functional layers such as an electron blocking layer, an exciton blocking layer, etc. in addition to the above-mentioned functional layers. Conversely, any of the above-mentioned layers may not be provided.

[0215] like Figure 1 As shown, the second light-emitting unit 502 preferably includes functional layers such as a second hole transport layer 112_2, a second electron transport layer 114_2, and an electron injection layer 115 in addition to the above-mentioned layers. In addition, the second light-emitting unit 502 may also include functional layers such as a hole blocking layer, an electron blocking layer, an exciton blocking layer, etc. in addition to the above-mentioned functional layers. Conversely, any of the above-mentioned layers may not be provided.

[0216] In addition, the intermediate layer 116 is at least Figure 1 The first electrode 101 in the embodiment has a first region 119, a third region 118 and a second region 117 on one side. The first region 119 is a region including a metal or a metal oxide, an organic compound (first organic compound) containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring as described in Embodiment 1. In addition, the second region 117 is a layer that generates charges by applying a voltage. The second region 117 is preferably a layer including an organic compound having a hole-transporting property and a substance having an electron-accepting property for the organic compound. The third region 118 is a layer composed of a material having an electron-transporting property and a specific LUMO energy level, and the driving voltage of the light-emitting device can be reduced by providing the third region. In addition, the reliability of the light-emitting device can be suppressed from decreasing. In addition, the luminous efficiency of the light-emitting device can be improved.

[0217] The specific structures of the first region 119 , the second region 117 , and the third region 118 have been described in detail in Embodiment 1, and thus repeated description will be omitted here.

[0218] Note that in this embodiment, it is preferable that the first electrode 101 is an electrode including an anode and the second electrode 102 is an electrode including a cathode. In addition, the first electrode 101 and the second electrode 102 are formed as a single-layer structure or a stacked-layer structure. When the electrodes have a stacked-layer structure, the layer in contact with the organic compound layer 103 serves as the anode or the cathode. When the electrodes have a stacked-layer structure, there is no restriction on the work function of the layers other than the layer in contact with the organic compound layer 103, and the material can be selected based on the required characteristics such as resistance value, processing convenience, reflectivity, light transmittance, and stability.

[0219] As the anode, it is preferred to use a metal, alloy, conductive compound, or mixture thereof with a large work function (specifically, 4.0 eV or more). Specifically, for example, indium oxide-tin oxide (ITO: Indium Tin Oxide), indium oxide-tin oxide containing silicon or silicon oxide (ITSO: Indium Tin Silicon Oxide), indium oxide-zinc oxide, indium oxide containing tungsten oxide and zinc oxide (IWZO), etc. are mentioned. Although these conductive metals or their oxide films are usually formed by sputtering, they can also be formed by applying a sol-gel method. As an example of a formation method, a method of depositing indium oxide-zinc oxide by sputtering using a target material having 1 wt% to 20 wt% of zinc oxide added to indium oxide can be cited. In addition, indium oxide (IWZO) containing tungsten oxide and zinc oxide can be formed by sputtering using a target material having 0.5 wt% to 5 wt% of tungsten oxide and 0.1 wt% to 1 wt% of zinc oxide added to indium oxide. In addition, as the material for the anode, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), aluminum (Al) or nitrides of metal materials (for example, titanium nitride) can be cited. In addition, the layer stacked with them can also be used as an anode. For example, a film of Al, Ti, and ITSO stacked in sequence on Ti has high efficiency due to good reflectivity and can achieve a high resolution of thousands of ppi, so it is preferred. Alternatively, graphene can also be used as a material for the anode. In addition, by using the composite material that can constitute the hole injection layer 111 described later as a layer in contact with the anode (typically a hole injection layer), the electrode material can be selected regardless of the work function.

[0220] The hole injection layer 111 is in contact with the anode and has the function of facilitating hole injection into the organic compound layer 103. The hole injection layer 111 can be formed using phthalocyanine compounds or complexes such as phthalocyanine (abbreviated as H2Pc) and copper phthalocyanine (abbreviated as CuPc); aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD); or polymers such as poly(3,4-ethylenedioxythiophene) / (polystyrenesulfonic acid) (abbreviated as PEDOT / PSS).

[0221] In addition, the hole injection layer 111 may be composed of a substance having electron acceptor properties. As the substance having electron acceptor properties, an organic compound having an electron withdrawing group (halogen group, cyano group) may be used, and examples thereof include 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), and 2-(7-dicyano-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile. In particular, compounds such as HAT-CN in which an electron-withdrawing group is bonded to a fused aromatic ring having multiple heteroatoms are thermally stable and therefore are preferred. In addition, [3] axial ene derivatives including electron-withdrawing groups (especially halogen groups such as fluorine groups and cyano groups) are preferred because their electron acceptability is very high. Specifically, examples include: α, α', α"-1,2,3-cyclopropane tris(ylidene) tris[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α, α', α"-1,2,3-cyclopropane tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], α, α', α"-1,2,3-cyclopropane tris[2,3,4,5,6-pentafluorophenylacetonitrile], etc. As a substance having electron acceptor properties, in addition to the above-mentioned organic compounds, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can also be used.

[0222] The hole injection layer 111 is preferably formed using a composite material including the above-mentioned material having an electron accepting property and an organic compound having a hole transporting property.

[0223] As the organic compound with hole transport property used in the composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, high molecular weight compounds (oligomers, dendrimers, polymers, etc.) can be used. As the organic compound with hole transport property used in the composite material, it is preferred to use an organic compound with a hole mobility of 1×10 -6 cm 2 / Vs or more organic compound. The organic compound with hole transport properties used in the composite material is preferably a compound containing a fused aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the fused aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, etc. are preferred. In addition, as the π-electron-rich heteroaromatic ring, a fused aromatic ring containing at least one of a pyrrole skeleton, a furan skeleton and a thiophene skeleton is preferred, and specifically a carbazole ring, a dibenzothiophene ring or a ring in which these rings are also fused with an aromatic ring or a heteroaromatic ring is preferred.

[0224] Such an organic compound having hole transport properties preferably has any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, it may be an aromatic amine having a substituent including a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine including a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to nitrogen of the amine via an arylene group. Note that when these organic compounds having hole transport properties are substances including N, N-bis(4-biphenyl)amino groups, a light-emitting device with a long life can be manufactured, so it is preferred.

[0225] Specific examples of the organic compound having a hole transport property include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4"-phenyltriphenylamine (abbreviated as BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviated as BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1 ,2-d]furan-8-amine (abbreviated as BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviated as BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-benzidine (abbreviated as ThBA1BP), 4-(2-naphthyl)-4',4"-diphenyltriphenylamine (abbreviated as BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4"-diphenyltriphenylamine (abbreviated as BBAβNBi), 4,4'- diphenyl-4"-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBAαNβNB), 4,4'-diphenyl-4"-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBAαNβNB-03), 4,4'-diphenyl-4"-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviated as: BBAPβNB-03), 4,4'-diphenyl-4"-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBA(βN2)B), 4,4'-diphenyl-4"-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBA(βN2)B-03), 4,4'-diphenyl-4"-(4;2'-binaphthyl- 1-yl) triphenylamine (abbreviated as: BBAβNαNB), 4,4'-diphenyl-4"-(5;2'-binaphthyl-1-yl) triphenylamine (abbreviated as: BBAβNαNB-02), 4-(4-biphenyl)-4'-(2-naphthyl)-4"-phenyltriphenylamine (abbreviated as: TPBiAβNB), 4-(3-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4"-phenyltriphenylamine (abbreviated as: mTPBiAβNBi), 4-(4-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4"-phenyltriphenylamine (abbreviated as: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviated as: 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]tri(biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazol-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4"-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBN BSF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluorene-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-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine ( Abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-4-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-3-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-2-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-1-amine, etc.

[0226] In addition, as materials with hole transport properties, as other aromatic amine compounds, 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), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can also be used.

[0227] By forming the hole injection layer 111, hole injection properties can be improved, so that a light-emitting device with a low driving voltage can be obtained.

[0228] Furthermore, among substances having electron accepting properties, organic compounds having electron accepting properties can be easily formed by vapor deposition and are therefore easy-to-use materials.

[0229] The hole transport layer 112 is formed to include an organic compound having a hole transport property. The organic compound having a hole transport property preferably has a 1×10 -6 cm 2 / Vs and above hole mobility.

[0230] Examples of the hole-transporting material include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviated as TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as mBPAFLP), and 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBA1BP). , 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluorene-2-amine (abbreviated as PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviated as PCBASF), etc.;1,3-Bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-bis(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviated as PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviated as BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviated as BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3 '-Bicarbazole (abbreviated as: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviated as: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviated as: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviated as: BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-3-yl-3,3'-9H,9 'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',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'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylene-2-yl)-3, Compounds having a carbazole skeleton such as 3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviated as PCCzTp), 9,9'-bis(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenyl-2-yl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, and 9-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]phenanthrene (abbreviated as PcPPn);Compounds having a thiophene skeleton, such as 4,4',4"-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV); and compounds having 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-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among them, compounds having an aromatic amine skeleton or a carbazole skeleton are preferred because they have good reliability and high hole transport properties and contribute to lowering the driving voltage. Note that as the material constituting the hole transport layer 112, the substances listed as the materials having hole transport properties for the composite material used for the hole injection layer 111 can also be appropriately used. ;

[0231] The light-emitting layer 113 (the light-emitting layer 113_1 and the light-emitting layer 113_2) is a layer containing a light-emitting substance, and preferably contains a light-emitting substance and a host material. Note that the light-emitting layer may also contain other materials. Alternatively, a stack of layers having different composition ratios may be used.

[0232] The light-emitting substance may be a fluorescent substance, a phosphorescent substance, a substance exhibiting thermally activated delayed fluorescence (TADF), or other light-emitting substances.

[0233] In the light-emitting layer, materials that can be used as the fluorescent substance include, for example, the following substances. Note that other fluorescent substances can also be used.

[0234] Examples thereof include 5,6-bis[4-(10-phenyl-9-anthracenyl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthracenyl)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-fluorene-9-yl)phenyl]pyrene-1,6-diamine (abbreviated as: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviated as: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthracenyl)triphenylamine (abbreviated as: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2- triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butyl perylene (abbreviation: TBP), 4-(10-phenyl-9-anthracenyl)-4'-(9-phenyl-9H-carbazole-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-carbazole-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] -2,7,10,15-tetramine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthracenyl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthracenyl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthracenyl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthracenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(biphenyl-2-yl)-2-anthracenyl]-N,N',N'-triphenyl-1,4-phenylenediamine )-N-[4-(9H-carbazole-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviated as: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviated as: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviated as: DPQd), rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenylnaphthacene (abbreviated as: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]vinyl}-6-methyl-4H-pyran-4-ylidene)malononitrile (abbreviated as: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4 -ylidene}malononitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5 H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)malononitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10FrA2Nbf(IV)-02), etc. In particular, condensed aromatic diamine compounds represented by pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn and 1,6BnfAPrn-03 are preferred because they have high hole-trapping properties, high luminous efficiency and high reliability. ,

[0235] In addition, 5,9-diphenyl-5,9-diaza-13b-borazinahexano[3,2,1-de]anthracene (abbreviation: DABNA1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazine-3-amine (abbreviation: DABNA2), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazine-3-amine (abbreviation: DABNA2), -7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetrakis(4-tert-butylphenyl)-5H,9H-[1,4]benzoazaboro[2,3,4-kl]phenazoneboro-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzoazaboro[2,3,4-kl]phenazoneboro (abbreviation: Me-tBu4DABNA), N 7 , N 7 , N 13 , N 13 , 5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaboro[2,3,4-kl][1,4]benzazaboro[4',3',2':4,5][1,4]benzazaboro[3,2-b]phenazoboro-7,13-diamine (abbreviation: ν-DABNA), 2-(4-tert-butylphenyl)benzo[5,6]indole[3,2,1-jk]benzo[b]carbazole (abbreviation: tBuPBibc) and other nitrogen- and boron-containing fused heteroaromatic compounds, especially compounds having a diaza-borazine-naphtho-anthracene skeleton, have a narrow emission spectrum and can obtain blue light emission with good color purity, so they can be appropriately used.

[0236] In addition, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazole-9-yl]-2,5,15,18-tetra(1,1-dimethylethyl)indol[3,2,1-de]indol[3',2',1':8,1][1,4]benzazaboro[2,3,4-kl]phenazoneboro (abbreviation: BBCz-G), 9,11-bis[3,6-bis(1,1-dimethylethyl)-9H-carbazole-9-yl]-2,5,15,18-tetra(1,1-dimethylethyl)indol[3',2',1'-de]indol[3',2',1':8,1][1,4]benzazaboro[2,3,4-kl]phenazoneboro (abbreviation: BBCz-Y), etc. can also be appropriately used.

[0237] When a phosphorescent substance is used as a light-emitting substance in the light-emitting layer, examples of usable materials include the following substances.

[0238] Examples include organic metal iridium complexes having 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) (abbreviated as [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Mptz)3]), and the like. tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Prptz1-Me)3]) and other organic metal iridium complexes having a 1H-triazole skeleton; fac-tris[1-(2,6-di isopropylphenyl)-2-phenyl-1H-imidazole]iridium (III) (abbreviated as [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium (III) (abbreviated as [Ir(dmpimpt-Me)3]), tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazole- 2-yl-κN3}-4-cyanophenyl-κC)(abbreviated as CNImIr) and the like having an imidazole skeleton; tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III)(abbreviated as [Ir(cb)3]) and the like having a benzimidazole skeleton; and bis[2-(4',6'-difluorophenyl)pyridinyl-N,C 2’]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviated as FIr6), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ ]iridium(III) picolinate (abbreviated as FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinium-N,C 2’ Iridium(III) picolinate (abbreviated as [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ ] Iridium (III) acetylacetonate (abbreviated as FIr(acac)) and other organic metal iridium complexes having a phenylpyridine derivative having an electron-withdrawing group as a ligand. The above substances are compounds that emit blue phosphorescence and have a luminescence peak in the wavelength region of 450nm to 520nm.

[0239] In addition, tris(4-methyl-6-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-tert-butyl-6-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonate)bis(6-methyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonate)bis(6-tert-butyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonate)bis(6-tert-butyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonate)bis[6-(2-norbornyl)-4-phenylpyrimidinyl]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonate)bis[5-methyl [Ir(mppr-iPr)2(acac)]) and other organic metal iridium complexes with a pyrimidine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine)iridium(III) (abbreviated as [Ir(mppr-Me)2(acac)] and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazine)iridium(III) (abbreviated as [Ir(mppr-iPr)2(acac)]; [Ir(mppr-iPr)2(acac)] and other organic metal iridium complexes with a pyrazine skeleton, such as tris(2-phenylpyridinium-N,C 2’ )iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinium-N,C 2’)iridium(III)acetylacetonate (abbreviated as [Ir(ppy)2(acac)]), bis(benzo[h]quinoline)iridium(III)acetylacetonate (abbreviated as [Ir(bzq)2(acac)]), tris(benzo[h]quinoline)iridium(III) (abbreviated as [Ir(bzq)3]), tris(2-phenylquinoline-N,C 2’ )iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinoline-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridyl-κN)benzofurano[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mbfpypy-d3)]), [2-d3-methyl-(2-pyridyl-κN)benzofurano[2,3-b]pyridine-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy-d3)]), [2-(4-d3-methyl-5-phenyl-2-pyridyl-κN2)phenyl-κC]bis[2-(5-d3-methyl-2 -pyridyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mdppy-d3)]), [2-methyl-(2-pyridyl-κN)benzofurano[2,3-b]pyridine-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy)]), [2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium (abbreviation: [Ir(ppy)2(mdppy)]), etc.; and rare earth metal complexes such as tris(acetylacetonate)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]). The above substances are mainly compounds that exhibit green phosphorescence and have a light emission peak in the wavelength region of 500 nm to 600 nm. In addition, since an organic metal iridium complex having a pyrimidine skeleton has particularly excellent reliability or light emission efficiency, it is particularly preferred.

[0240] In addition, organic gold metals having a pyrimidine skeleton include: (diisobutyrylmethane)bis[4,6-bis(3-methylphenyl)pyrimidinyl]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinyl](dipivaloylmethanone)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-di(naphthalene-1-yl)pyrimidinyl](dipivaloylmethanone)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]) and the like. Iridium complexes; (acetylacetonato)bis(2,3,5-triphenylpyrazine)iridium(III) (abbreviated as [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazine)(dipivaloylmethanone)iridium(III) (abbreviated as [Ir(tppr)2(dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxaline]iridium(III) (abbreviated as [Ir(Fdpq)2(acac)]) and other organometallic iridium complexes with pyrazine skeletons; tris(1-phenylisoquinoline-N,C 2’ )iridium(III) (abbreviated as [Ir(piq)3]), bis(1-phenylisoquinoline-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), (3,7-diethyl-4,6-nonanedione-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolyl-κN]phenyl-κC]iridium(III), (3,7-diethyl-4,6-nonanedione-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolyl-κN]phenyl-κC]iridium(III) and the like organic metal iridium complexes having a pyridine skeleton 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum (II) (abbreviated as PtOEP) and other platinum complexes; and tris (1,3-diphenyl-1,3-propanedione (propanedionato)) (monophenanthroline) europium (III) (abbreviated as [Eu (DBM) 3 (Phen)]), tris [1- (2-thenoyl) -3,3,3-trifluoroacetone] (monophenanthroline) europium (III) (abbreviated as [Eu (TTA) 3 (Phen)] and other rare earth metal complexes. The above substances are compounds that exhibit red phosphorescence and have a luminescence peak in the wavelength region of 600nm to 700nm. In addition, an organic metal iridium complex having a pyrazine skeleton can obtain red luminescence with good chromaticity.

[0241] Furthermore, in addition to the above-mentioned phosphorescent compounds, known phosphorescent compounds may be selected and used.

[0242] As TADF materials, fullerene and its derivatives, acridine and its derivatives, and eosin derivatives can be used. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can also be mentioned. As the metal-containing porphyrin, for example, there can be mentioned protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), protoporphyrin-tin fluoride complex (SnF2(Etio I)) and octaethylporphyrin-platinum chloride complex (PtCl2OEP) etc. represented by the following structural formula.

[0243] [Chemical formula 5]

[0244] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindol[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazine-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), and 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn) represented by the following structural formula can also be used. Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, such as 5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-oxanthene-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridinium)phenyl]sulfone (abbreviation: DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviation: ACRSA). The heterocyclic compound has a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, and both electron transport and hole transport are high, so it is preferred. Among them, in the skeleton with a π-electron-deficient heteroaromatic ring, the pyridine skeleton, the diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) and the triazine skeleton are stable and have good reliability, so it is preferred. In particular, the electron acceptor properties of the benzofuran pyrimidine skeleton, the benzothiophene pyrimidine skeleton, the benzofuran pyrazine skeleton, and the benzothiophene pyrazine skeleton are high and have good reliability, so it is preferred. In addition, in the skeleton with a π-electron-rich heteroaromatic ring, the acridine skeleton, the phenoxazine skeleton, the phenothiazine skeleton, the furan skeleton, the thiophene skeleton and the pyrrole skeleton are stable and have good reliability, so it is preferred to have at least one of the above skeletons. In addition, as a furan skeleton, a dibenzofuran skeleton is preferably used, and as a thiophene skeleton, a dibenzothiophene skeleton is preferably used. As the pyrrole skeleton, it is particularly preferred to use an indole skeleton, a carbazole skeleton, an indolecarbazole skeleton, a bicarbazole skeleton, and a 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton. In a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded, the electron donation property of the π-electron-rich heteroaromatic ring and the electron acceptance property of the π-electron-deficient heteroaromatic ring are both high, and the energy difference between the S1 energy level and the T1 energy level becomes small, so that thermally activated delayed fluorescence can be efficiently obtained, so it is particularly preferred. Note that an aromatic ring bonded with an electron-withdrawing group such as a cyano group can also be used instead of a π-electron-deficient heteroaromatic ring. In addition, as a π-electron-rich skeleton, an aromatic amine skeleton, a phenazine skeleton, etc. can be used.In addition, as the π-electron-deficient skeleton, a xanthene skeleton, a thioxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane and boranthrene, an aromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanophenyl, a heteroaromatic ring, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. can be used. In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used to replace at least one of the π-electron-deficient heteroaromatic ring and the π-electron-rich heteroaromatic ring.

[0245] [Chemical formula 6]

[0246] TADF materials refer to materials with a small difference between the S1 energy level and the T1 energy level and the function of converting triplet excitation energy into singlet excitation energy through anti-intersystem crossing. Therefore, triplet excitation energy can be up-converted into singlet excitation energy (anti-intersystem crossing) through tiny thermal energy and singlet excited states can be efficiently generated. In addition, triplet excitation energy can be converted into luminescence.

[0247] The exciplex formed by two substances in an excited state has the function of a TADF material that can convert triplet excitation energy into singlet excitation energy because the difference between the S1 energy level and the T1 energy level is extremely small.

[0248] Note that as an indicator of the T1 level, a phosphorescence spectrum observed at a low temperature (e.g., 77 K to 10 K) can be used. With respect to the TADF material, when the wavelength energy of an extrapolated line obtained by cutting a line at the tail of the short wavelength side of the fluorescence spectrum is taken as the S1 level and the wavelength energy of an extrapolated line obtained by cutting a line at the tail of the short wavelength side of the phosphorescence spectrum is taken as the T1 level, it is preferred that the difference between the S1 level and the T1 level be 0.3 eV or less, more preferably 0.2 eV or less.

[0249] In addition, when a TADF material is used as a light-emitting substance, the S1 energy level of the host material is preferably higher than the S1 energy level of the TADF material. In addition, the T1 energy level of the host material is preferably higher than the T1 energy level of the TADF material.

[0250] As the host material of the light-emitting layer, various carrier transport materials such as a material having an electron transport property and / or a material having a hole transport property or the above-mentioned TADF material can be used.

[0251] As the material having hole transport properties, it is preferred to use an organic compound having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton. As the π-electron-rich heteroaromatic ring, it is preferred to use a fused aromatic ring containing at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton and a pyrrole skeleton, and specifically preferably a carbazole ring, a dibenzothiophene ring or a ring in which these rings are further fused with an aromatic ring or a heteroaromatic ring.

[0252] Such an organic compound having hole transport properties preferably has any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, it may be an aromatic amine having a substituent including a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine including a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to nitrogen of the amine via an arylene group. Note that when these organic compounds having hole transport properties are substances including N, N-bis(4-biphenyl)amino groups, a light-emitting device with a long life can be manufactured, so it is preferred.

[0253] Examples of such organic compounds include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviated as TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as mBPAFLP), 4'-phenyl-4 ... -(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBA1BP), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviated as: PCBAF), N-phenyl -N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviated as PCBASF) and other compounds having an aromatic amine skeleton; 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-bis(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviated as PCCP) and other compounds having a carbazole skeleton; 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as DB T3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviated as: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as: DBTFLP-IV) and other compounds having a thiophene skeleton; and 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviated as: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as: mmDBFFLBi-II) and other compounds having a furan skeleton. Among them, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton have good reliability and high hole transport properties and help to reduce the driving voltage, so they are preferred. In addition, organic compounds listed as examples of materials with hole transport properties as hole transport layers can also be used.

[0254] As materials having electron transport properties, for example, metal complexes such as bis(10-hydroxybenzo[h]quinoline)beryllium(II) (abbreviated as BeBq2), bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviated as BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviated as ZnPBO), bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ), and organic compounds containing π-electron-deficient heteroaromatic rings are preferably used. As organic compounds containing π-electron-deficient heteroaromatic skeletons, for example, organic compounds containing heteroaromatic rings having azole skeletons, organic compounds containing heteroaromatic rings having pyridine skeletons, organic compounds containing heteroaromatic rings having diazine skeletons, and organic compounds containing heteroaromatic rings having triazine skeletons can be cited.

[0255] Among them, organic compounds containing heteroaromatic rings having a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), organic compounds containing heteroaromatic rings having a pyridine skeleton, or organic compounds containing heteroaromatic rings having a triazine skeleton have good reliability, so they are preferred. In particular, organic compounds containing heteroaromatic rings having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings having a triazine skeleton have high electron transport properties, which helps to reduce the driving voltage. In addition, benzofuranopyrimidine skeletons, benzothiophenopyrimidine skeletons, benzofuranopyrazine skeletons, and benzothiophenopyrazine skeletons have high electron acceptor properties and high reliability, so they are preferred.

[0256] Examples of organic compounds containing a π-electron-deficient heteroaromatic ring skeleton include: 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-[ organic compounds having an azole skeleton, such as 3-(dibenzothiophene-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviated as BzOs); 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviated as 35DCzPPy), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviated as TmPyPB), bathophenanthroline (abbreviated as BPhen), bathocuproin (abbreviated as BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), 2,2'-(1,3-phenylene)bis(9- Organic compounds containing a heteroaromatic ring having a pyridine skeleton, such as 2-[4-(2-triphenylene)phenyl]-1,10-phenanthroline (abbreviated as: mPPhen2P), 2-[3-(2-triphenylene)phenyl]-1,10-phenanthroline (abbreviated as: mTpPPhen), 2-phenyl-9-(2-triphenylene)-1,10-phenanthroline (abbreviated as: Ph-TpPhen), 2-[4-(9-phenanthrenyl)-1-naphthyl]-1,10-phenanthroline (abbreviated as: PnNPhen), 2-[4-(2-triphenylene)phenyl]-1,10-phenanthroline (abbreviated as: pTpPPhen); 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as: 2mDBTPDBq-I I), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as: 2CzPDBq-III), 7-[3-(dibenzothiophene-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-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPn P2Pm), 4,6-bis[3-(dibenzothiophene-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-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-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophene-4-yl)phenyl] ]benzofurano[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)1,1'-biphenyl-3-yl]naphtho[1',2':4,5]furano[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthyl)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mD BtPBfpm), 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-naphthyl-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidineorganic compounds having a diazine skeleton, such as 5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz); 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluorene]-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: mBnfBP Tzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as mBnfBPTzn-02), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviated as mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine Phenyl-1,3,5-triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3 , 5-triazine (abbreviated as: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-phenylindole[2,3-a]carbazole (abbreviated as: BP-Icz(II)Tzn), 2-[3'-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',An organic compound containing a heteroaromatic ring having a triazine skeleton, such as [1-(1-(1-terphenyl)-4-yl)-1-dibenzofuranyl]-1,3,5-triazine (abbreviation: mBP-TPDBfTzn). An organic compound containing a heteroaromatic ring having a diazine skeleton, an organic compound containing a heteroaromatic ring having a pyridine skeleton, or an organic compound containing a heteroaromatic ring having a triazine skeleton has good reliability and is therefore preferred. In particular, an organic compound containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and an organic compound containing a heteroaromatic ring having a triazine skeleton have high electron transport properties, which contribute to reducing the driving voltage.

[0257] In addition, bipolar organic compounds such as 3,6-bis(diphenylamino)-9-[4-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9H-carbazole (abbreviated as: DACT-II), 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as: 2mPCCzPDBq) can also be used.

[0258] As a TADF material that can be used as a host material, the same material as the material cited above as a TADF material can be used. When a TADF material is used as a host material, the triplet excitation energy generated by the TADF material is converted into singlet excitation energy through reverse intersystem crossing and further energy is transferred to the luminescent material, thereby improving the luminous efficiency of the light-emitting device. At this time, the TADF material is used as an energy donor and the luminescent material is used as an energy acceptor.

[0259] This is very effective when the above-mentioned luminescent material is a fluorescent luminescent material. In addition, at this time, in order to obtain high luminous efficiency, the S1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent luminescent material. In addition, the T1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent luminescent material. Therefore, the T1 energy level of the TADF material is preferably higher than the T1 energy level of the fluorescent luminescent material.

[0260] In addition, it is preferable to use a TADF material that emits light at a wavelength overlapping with the absorption band on the lowest energy side of the fluorescent material. This is preferable because the excitation energy is smoothly transferred from the TADF material to the fluorescent material, and light emission can be obtained efficiently.

[0261] In order to efficiently generate singlet excitation energy from triplet excitation energy through anti-intersystem crossing, carrier recombination is preferably generated in TADF material. In addition, it is preferred that the triplet excitation energy generated in TADF material is not transferred to the triplet excitation energy of fluorescent material. For this reason, the fluorescent material preferably has a protective group around the luminophore (the skeleton that becomes the cause of luminescence) possessed by the fluorescent material. As the protective group, it is preferably a substituent without a π bond, preferably a saturated hydrocarbon, specifically, an alkyl group having a carbon number of more than 3 and less than 10, a substituted or unsubstituted cycloalkyl group having a carbon number of more than 3 and less than 10, and a trialkylsilyl group having a carbon number of more than 3 and less than 10, more preferably having a plurality of protective groups. The substituent without a π bond has almost no function of transmitting carriers, so it has almost no effect on carrier transmission or carrier recombination, and the luminophore of the TADF material and the fluorescent material can be kept away from each other. Here, the luminophore refers to the atomic group (skeleton) that becomes the cause of luminescence in the fluorescent material. The luminophore preferably has a π-bond skeleton, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of such luminophores include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, In particular, the naphthalene skeleton, the anthracene skeleton, the fluorene skeleton, the Fluorescent substances having a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because they have high fluorescence quantum yields.

[0262] In the case where a fluorescent material is used as a light-emitting material, a material having an anthracene skeleton is preferably used as a host material. By using a substance having an anthracene skeleton as a host material of a fluorescent material, a light-emitting layer having high luminous efficiency and durability can be achieved. Among the substances having an anthracene skeleton used as a host material, substances having a diphenylanthracene skeleton (especially a 9,10-diphenylanthracene skeleton) are chemically stable, so they are preferred. In addition, in the case where the host material has a carbazole skeleton, the injection / transport properties of holes are improved, so it is preferred. In the case of a benzocarbazole skeleton comprising a benzene ring fused to carbazole, its HOMO energy level is about 0.1eV shallower than that of a host material having a carbazole skeleton, and holes are easily injected, so it is more preferred. In particular, in the case where the host material has a dibenzocarbazole skeleton, its HOMO energy level is about 0.1eV shallower than that of a host material having a carbazole skeleton, not only are holes easily injected, but also hole transport and heat resistance are improved, so it is preferred. Therefore, a more preferred host material is one having a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). Note that from the viewpoint of the hole injection / transport property, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as CzPA), 7-[4-(10-phenyl-9-anthracenyl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviated as cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthracenyl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviated as 2mBnfPPA), 9-phenyl-10-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-9H-carbazole (abbreviated as PCPN), -biphenyl-4'-yl]-anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α, β-ADN), 2-(10-phenylanthracene-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthracenyl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), etc. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred because they exhibit very good properties.

[0263] In addition, the host material may also be a material mixed with multiple substances. When a mixed host material is used, it is preferred to mix a material having electron transport properties and a material having hole transport properties. By mixing a material having electron transport properties and a material having hole transport properties, it is easier to adjust the transport properties of the light-emitting layer 113, and it is also easier to control the recombination area. The weight ratio of the content of the material having hole transport properties and the material having electron transport properties is 1:19 to 19:1.

[0264] Note that as part of the above mixed material, a phosphorescent substance may be used. When a fluorescent substance is used as a light-emitting substance, the phosphorescent substance may be used as an energy donor for supplying excitation energy to the fluorescent substance.

[0265] In addition, these mixed materials can also be used to form an exciplex. By selecting the mixed material in a manner to form an exciplex that emits light overlapping the wavelength of the absorption band on the lowest energy side of the luminescent substance, energy transfer can be smoothed, thereby efficiently obtaining luminescence, so it is preferred. In addition, by adopting this structure, the driving voltage can be reduced, so it is preferred.

[0266] Note that at least one of the materials forming the exciplex may be a phosphorescent substance. This allows efficient conversion of triplet excitation energy into singlet excitation energy via anti-intersystem crossing.

[0267] Regarding the combination of materials that efficiently form an exciplex, the HOMO energy level of the material having hole transport properties is preferably higher than the HOMO energy level of the material having electron transport properties. In addition, the LUMO energy level of the material having hole transport properties is preferably higher than the LUMO energy level of the material having electron transport properties. Note that the LUMO energy level and HOMO energy level of the material can be obtained from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV) measurement.

[0268] Note that the formation of an exciplex can be confirmed, for example, by comparing the emission spectra of a material having hole transport properties, the emission spectra of a material having electron transport properties, and the emission spectra of a mixed film formed by mixing these materials. When the emission spectrum of the mixed film is observed to drift toward the long wavelength side compared to the emission spectrum of each material (or to have a new peak on the long wavelength side), it indicates that an exciplex has been formed. Alternatively, the transient photoluminescence (PL) of a material having hole transport properties, the transient PL of a material having electron transport properties, and the transient PL of a mixed film formed by mixing these materials are compared. When the transient response is different, such as the ratio of the transient PL lifetime of the mixed film to the transient PL lifetime of each material is increased, it indicates that an exciplex has been formed. In addition, the above-mentioned transient PL can be referred to as transient electroluminescence (EL). In other words, the formation of an exciplex can be confirmed by comparing the transient EL of a material having hole transport properties, the transient EL of a material having electron transport properties, and the transient EL of a mixed film of these materials and observing the difference in transient response.

[0269] In addition, the light-emitting layer 113 preferably contains a third organic compound having a π-deficient heteroaromatic ring as a host material. In addition, the third π-deficient heteroaromatic ring is preferably the same π-deficient heteroaromatic ring as the second π-deficient heteroaromatic ring contained in the first layer of the intermediate layer. In addition, the third organic compound and the second organic compound are preferably the same.

[0270] The electron transport layer 114 (the first electron transport layer 114_1 and the second electron transport layer 114_2) is a layer containing a material having an electron transport property. As the electron transport material, it is preferable to use a material having an electron mobility of 1×10 -7 cm 2 / Vs or more, it is more preferable to use the material having an electron mobility of 1×10 -6 cm 2 / Vs or more. In addition, as long as the electron transport property is higher than the hole transport property, substances other than the above can be used. As the above-mentioned organic compound, it is preferred to use an organic compound containing a π-electron-deficient heteroaromatic ring. As an organic compound containing a π-electron-deficient heteroaromatic ring, for example, it is preferred to use any one or more of an organic compound containing a heteroaromatic ring having an azole skeleton, an organic compound containing a heteroaromatic ring having a pyridine skeleton, an organic compound containing a heteroaromatic ring having a diazine skeleton, and an organic compound containing a heteroaromatic ring having a triazine skeleton.

[0271] As an organic compound with electron transport properties that can be used for the first electron transport layer 114_1 and the second electron transport layer 114_2, the organic compound with electron transport properties that can be used as the first light-emitting layer 113_1 and the second light-emitting layer 113_2 can be used in the same manner. Among them, an organic compound containing a heteroaromatic ring having a diazine skeleton, an organic compound containing a heteroaromatic ring having a pyridine skeleton, or an organic compound containing a heteroaromatic ring having a triazine skeleton has good reliability, so it is preferred. In particular, an organic compound containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and an organic compound containing a heteroaromatic ring having a triazine skeleton have high electron transport properties, which helps to reduce the driving voltage. Among them, it is preferred to use organic compounds having a phenanthroline skeleton such as mTpPPhen, PnNPhen and mPPhen2P, and it is more preferred to use an organic compound having a phenanthroline dimer structure such as mPPhen2P because it has good stability.

[0272] Furthermore, the first electron transport layer preferably contains an organic compound having an electron transport property with an acid dissociation constant pKa of less than 4.

[0273] In addition, the first electron transport layer 114_1 and the second electron transport layer 114_2 may also have a stacked structure. In addition, when the second electron transport layer 114_2 has a stacked structure, the layer in contact with the second light-emitting layer 113_2 may also be used as a hole blocking layer. When the electron transport layer in contact with the light-emitting layer is used as a hole blocking layer, it is preferred to use a material whose HOMO energy level is 0.5 eV or more deeper than the HOMO energy level of the material contained in the light-emitting layer.

[0274] In addition, the electron transport layer sandwiched between the light-emitting layer and the intermediate layer preferably contains an organic compound having a π-electron-deficient heteroaromatic ring, and the organic compound having a π-electron-deficient heteroaromatic ring is preferably an organic compound different from the organic compound having a π-electron-deficient heteroaromatic ring contained in the light-emitting layer. Figure 1 In the embodiment, it is preferred that the first electron transport layer 114_1 includes a fourth organic compound having a π-electron-deficient heteroaromatic ring, and the fourth organic compound is different from the third organic compound having a third π-electron-deficient heteroaromatic ring included in the first light-emitting layer 113_1.

[0275] As the electron injection layer 115, the electron transport layer ( Figure 1A layer containing alkali metals, alkaline earth metals, or compounds thereof such as lithium oxide (Li2O), lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-hydroxyquinoline-lithium (abbreviated as: Liq) is provided between the second electron transport layer 114_2 in the second electrode 102. The electron injection layer 115 can use a layer or an electron compound (electride) containing an alkali metal, alkaline earth metal, or a compound thereof in a layer composed of a substance having electron transport properties. As an electron compound, for example, a substance in which electrons are added to a mixed oxide of calcium and aluminum at a high concentration can be cited.

[0276] The electron-injection layer 115 may be made of any of the above substances alone, or may be made of a layer containing a substance having an electron-transport property and any of the above substances.

[0277] Note that a layer containing a fluoride of an alkali metal or alkaline earth metal in a microcrystalline state at a concentration of 50 wt % or more may be used as the electron injection layer 115. Since this layer has a low refractive index, a light-emitting device with better external quantum efficiency can be provided.

[0278] The second electrode 102 is an electrode including a cathode. The second electrode 102 may also have a laminated structure, in which case the layer in contact with the organic compound layer 103 is used as a cathode. As a material forming the cathode, metals, alloys, conductive compounds, and mixtures thereof with a small work function (specifically, less than 3.8 eV) may be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) or cesium (Cs), elements belonging to Group 1 or Group 2 in the periodic table such as magnesium (Mg), calcium (Ca), or strontium (Sr), alloys containing them (MgAg, AlLi), compounds (lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), etc.), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing them. However, by providing an electron injection layer 115 or a thin film of the above-mentioned material with a small work function between the second electrode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, indium oxide-tin oxide containing silicon or silicon oxide, etc. can be used as cathodes regardless of the size of the work function.

[0279] When the second electrode 102 is composed of a material that is transparent to visible light, a light-emitting device that emits light from the second electrode 102 side can be formed. When the first electrode 101 is composed of a material that is transparent to visible light, a light-emitting device that emits light from the first electrode 101 side can be formed.

[0280] These conductive materials can be formed by dry methods such as vacuum deposition and sputtering, inkjet, spin coating, etc. Alternatively, they can be formed by wet methods such as sol-gel or by wet methods using a paste of a metal material.

[0281] The organic compound layer 103 can be formed by various methods, whether dry or wet, such as vacuum deposition, gravure printing, rotogravure printing, screen printing, inkjet printing, or spin coating.

[0282] In addition, the electrodes or layers described above may also be formed by using different deposition methods.

[0283] Although in Figure 1 1 and 2 illustrate a light-emitting device having two light-emitting units, but a light-emitting device having three or more light-emitting units stacked can be similarly applied. As in the light-emitting device according to this embodiment, by separating and arranging a plurality of light-emitting units between a pair of electrodes using an intermediate layer 116, the element can achieve high-brightness light emission while maintaining a low current density, and can achieve an element with a long life. In addition, a light-emitting device capable of low voltage driving and low power consumption can be achieved.

[0284] In addition, by making the emission colors of each light-emitting unit different, the desired color of light can be obtained in the entire light-emitting device. For example, by obtaining red and green emission colors from the first light-emitting unit and blue emission color from the second light-emitting unit in a light-emitting device having two light-emitting units, a light-emitting device that emits white light in the entire light-emitting device can be obtained.

[0285] In addition, the organic compound layer 103, the first light-emitting unit 501, the second light-emitting unit 502, the charge generation layer and other layers and electrodes can be formed by, for example, evaporation (including vacuum evaporation), droplet jetting (also known as inkjet), coating, gravure printing, etc. In addition, it can also include low molecular weight materials, medium molecular weight materials (including oligomers, dendritic polymers) or high molecular weight materials.

[0286] Figure 2 The diagram shows two adjacent tandem light-emitting elements (light-emitting device 130c and light-emitting device 130d) manufactured by photolithography.

[0287] The light emitting device 130c includes an organic compound layer 103c between the first electrode 101c and the second electrode 102 on the insulating layer 175. The organic compound layer 103c has a structure in which the first light emitting unit 501c and the second light emitting unit 502c are stacked via the intermediate layer 116c. Figure 2An example of stacking two light-emitting units is shown, but more than three light-emitting units may be stacked. The first light-emitting unit 501c includes a hole injection layer 111c, a first hole transport layer 112c_1, a first light-emitting layer 113c_1, and a first electron transport layer 114c_1. The intermediate layer 116c includes a third region 118c, a second region 117c, and a first region 119c. The second light-emitting unit 502c includes a second hole transport layer 112c_2, a second light-emitting layer 113c_2, a second electron transport layer 114c_2, and an electron injection layer 115.

[0288] The light emitting device 130d includes an organic compound layer 103d between a first electrode 101d and a second electrode 102 on an insulating layer 175. The organic compound layer 103d has a structure in which a first light emitting unit 501d and a second light emitting unit 502d are stacked via an intermediate layer 116d. Figure 2 An example of stacking two light-emitting units is shown, but more than three light-emitting units may be stacked. The first light-emitting unit 501d includes a hole injection layer 111d, a first hole transport layer 112d_1, a first light-emitting layer 113d_1, and a first electron transport layer 114d_1. The intermediate layer 116d includes a second region 117d, a third region 118d, and a first region 119d. The second light-emitting unit 502d includes a second hole transport layer 112d_2, a second light-emitting layer 113d_2, a second electron transport layer 114d_2, and an electron injection layer 115.

[0289] In the light-emitting device 130c and the light-emitting device 130d, the intermediate layer 116c and the intermediate layer 116d preferably have the structure described in Embodiment 1.

[0290] Note that the electron injection layer 115 and the second electrode 102 are preferably continuous layers used in common by the light-emitting device 130c and the light-emitting device 130d. In addition, the layers included in the organic compound layer 103c other than the electron injection layer 115 and the layers included in the organic compound layer 103d other than the electron injection layer 115 are independent of each other because they are processed by photolithography after forming the second electron transport layer 114c_2 and after forming the second electron transport layer 114d_2, respectively. In addition, the end portions (contours) of the layers included in the organic compound layer 103c other than the electron injection layer 115 are processed by photolithography, so they are roughly aligned in a direction perpendicular to the substrate. The end portions (contours) of the layers included in the organic compound layer 103d other than the electron injection layer 115 are processed by photolithography, so they are roughly aligned in a direction perpendicular to the substrate.

[0291] In addition, since the processing is performed by photolithography, there is a gap d between the organic compound layer 103c and the organic compound layer 103d. In addition, since the organic compound is processed by photolithography, the distance between the first electrode 101c and the first electrode 101d can be smaller than the distance when mask evaporation is performed, that is, it can be greater than 0.5 μm and less than 5 μm.

[0292] The light-emitting device according to one embodiment of the present invention having the above-described structure can be a light-emitting device having high current efficiency and excellent reliability and in which an increase in driving voltage is suppressed.

[0293] Although the light-emitting device of one embodiment of the present invention is particularly preferably used as a light-emitting device manufactured through a photolithography process, a light-emitting device manufactured without a photolithography process also has high stability to the atmosphere, thereby improving the yield, and the atmosphere does not need to be strictly managed during the manufacturing process, thereby helping to reduce costs.

[0294] Implementation 3 In this embodiment, an embodiment in which a light-emitting device which is one embodiment of the present invention is used as a display element of a display device is described.

[0295] like Figure 3A and Figure 3B As shown, a plurality of light emitting devices 130 are formed on an insulating layer 175 and constitute a display device.

[0296] The display device includes a pixel portion 177 in which a plurality of pixels 178 are arranged in a matrix. The pixel 178 includes a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0297] In this specification, for example, when describing the common contents among sub-pixel 110R, sub-pixel 110G, and sub-pixel 110B, sub-pixel 110 may be referred to as sub-pixel 110. Similarly, when describing the common contents among other components distinguished by letters, the letters may be omitted.

[0298] Sub-pixel 110R emits red light, sub-pixel 110G emits green light, and sub-pixel 110B emits blue light. Thus, an image can be displayed on pixel portion 177. In the present embodiment, sub-pixels of three colors, red (R), green (G), and blue (B), are used as examples for description, but a combination of sub-pixels of other colors may also be used. In addition, the number of sub-pixels is not limited to three, and four or more may also be used. As four sub-pixels, for example, there may be: sub-pixels of four colors, R, G, B, and white (W); sub-pixels of four colors, R, G, B, and yellow (Y); and sub-pixels of four colors, R, G, B, and infrared light (IR); and the like.

[0299] In this specification and the like, the row direction may be referred to as the X direction and the column direction may be referred to as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly intersect.

[0300] exist Figure 3A In the example shown, sub-pixels of different colors are arranged in the X direction, and sub-pixels of the same color are arranged in the Y direction. Note that sub-pixels of different colors may be arranged in the Y direction, and sub-pixels of the same color may be arranged in the X direction.

[0301] The connection portion 140 is provided outside the pixel portion 177, and a region 141 may be provided. The region 141 is provided between the pixel portion 177 and the connection portion 140. The organic compound layer 103 is provided in the region 141. In addition, the connection portion 140 is provided with a conductive layer 151C.

[0302] exist Figure 3A In the example shown, the region 141 and the connection portion 140 are located on the right side of the pixel portion 177, but there is no particular limitation on the positions of the region 141 and the connection portion 140. In addition, the region 141 and the connection portion 140 may be one or more.

[0303] Figure 3B It is along Figure 3A An example of a cross-sectional view along the dot-dash line A1-A2 in FIG. Figure 3B As shown, the display device includes an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and on the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is disposed on a substrate (not shown). The insulating layer 175, the insulating layer 174, and the insulating layer 173 are provided with openings that reach the conductive layer 172, and a plug 176 is provided in a manner of being embedded in the opening.

[0304] In the pixel portion 177, the light emitting device 130 is provided on the insulating layer 175 and the plug 176. In addition, a protective layer 131 is provided so as to cover the light emitting device 130. The substrate 120 is bonded to the protective layer 131 by the resin layer 122. In addition, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are preferably provided between adjacent light emitting devices 130.

[0305] Figure 3B Although the cross sections of the plurality of inorganic insulating layers 125 and the plurality of insulating layers 127 are shown, the inorganic insulating layers 125 and the insulating layers 127 are preferably formed as one layer connected to each other when the display device is viewed from above. In other words, the insulating layer 127 is preferably an insulating layer having an opening on the first electrode.

[0306] exist Figure 3B130R, 130G, and 130B are shown as the light emitting devices 130. The light emitting devices 130R, 130G, and 130B may emit light of different colors from each other. 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. In addition, the light emitting device 130R, the light emitting device 130G, or the light emitting device 130B may also emit other visible light or infrared light.

[0307] The display device of one embodiment of the present invention may have, for example, a top emission structure that emits light in a direction opposite to a substrate on which a light-emitting device is formed. Alternatively, the display device of one embodiment of the present invention may have a bottom emission structure.

[0308] The light-emitting device 130R has the structure described in Embodiment 1 and Embodiment 2. The light-emitting device 130R includes a first electrode 101R (pixel electrode) composed of a conductive layer 151R and a conductive layer 152R, a first EL layer 104R on the first electrode 101R, an organic compound layer (a second EL layer 105 on the first EL layer 104R), and a second electrode 102 (common electrode) on the second EL layer 105. The second EL layer 105 is preferably located closer to the second electrode 102 (common electrode) than the light-emitting layer, and is preferably a hole blocking layer, a second electron transport layer, or an electron injection layer, or a stack thereof. By having this structure, damage to the light-emitting layer or the active layer during the photolithography process can be suppressed, and good film quality and electrical characteristics can be expected.

[0309] The light-emitting device 130G has the structure described in Embodiment 1 and Embodiment 2. The light-emitting device 130G includes a first electrode 101G (pixel electrode) including a conductive layer 151G and a conductive layer 152G, a first EL layer 104G on the first electrode 101G, a second EL layer 105 on the first EL layer 104G, and a second electrode 102 (common electrode) on the second EL layer 105. The second EL layer 105 is preferably a hole blocking layer, a second electron transport layer, an electron injection layer, or a stack of these.

[0310] The light-emitting device 130B has the structure described in Embodiment 1 and Embodiment 2. The light-emitting device 130B includes a first electrode 101B (pixel electrode) including a conductive layer 151B and a conductive layer 152B, a first EL layer 104B on the first electrode 101B, a second EL layer 105 on the first EL layer 104B, and a second electrode 102 (common electrode) on the second EL layer 105. The second EL layer 105 is preferably a hole blocking layer, a second electron transport layer, an electron injection layer, or a stack of these.

[0311] One of the pixel electrode (first electrode) and the common electrode (second electrode) included in the light emitting device is used as an anode, and the other is used as a cathode. In this embodiment, unless otherwise specified, it is sometimes assumed that the pixel electrode is used as an anode and the common electrode is used as a cathode.

[0312] The first EL layer 104R, the first EL layer 104G, and the first EL layer 104B are each independent in the form of an island or independent in the form of an island for each luminescent color. Note that the first EL layer 104R, the first EL layer 104G, and the first EL layer 104B preferably do not overlap each other. By providing the first EL layer 104 in the form of an island for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in a high-definition display device. Thus, crosstalk can be prevented to realize a display device with extremely high contrast. In particular, a display device with high current efficiency at low brightness can be realized.

[0313] The island-shaped first EL layer 104 is formed by depositing an EL film and processing the EL film by photolithography.

[0314] In the display device of one embodiment of the present invention, the first electrode 101 (pixel electrode) of the light-emitting device preferably has a stacked structure. Figure 3B In the illustrated example, the first electrode 101 of the light emitting device 130 has a stacked-layer structure of a conductive layer 151 provided on the insulating layer 171 side and a conductive layer 152 provided on the organic compound layer side.

[0315] For example, a metal material can be used as the conductive layer 151. Specifically, for example, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys obtained by appropriately combining these metals can be used.

[0316] As the conductive layer 152, an oxide containing any one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, it is preferable to use a conductive oxide containing any one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. In particular, indium tin oxide containing silicon has a large work function, for example, 4.0 eV or more, so it can be preferably used as the conductive layer 152.

[0317] Each of the conductive layer 151 and the conductive layer 152 may have a stacked structure including a plurality of layers of different materials. In this case, the conductive layer 151 may include a layer using a material that can be used for the conductive layer 152 such as a conductive oxide, and the conductive layer 152 may include a layer using a material that can be used for the conductive layer 151 such as a metal material. For example, when the conductive layer 151 has a stacked structure of two or more layers, the layer in contact with the conductive layer 152 may be a layer using a material that can be used for the conductive layer 152.

[0318] The end of the conductive layer 151 preferably has a tapered shape. Specifically, the end 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. By making the side surface of the conductive layer 152 have a tapered shape, the coverage of the first EL layer 104 provided along the side surface of the conductive layer 152 can be improved.

[0319] In a display device of one embodiment of the present invention, the light-emitting device 130 has the structure shown in embodiments 1 and 2, thereby providing a light-emitting device with low driving voltage and high luminous efficiency having high moisture resistance, high water resistance, high oxygen resistance, and high chemical resistance.

[0320] Next, refer to 4A to 9C Description Figure 3A An example of a method for manufacturing a display device having the structure shown.

[0321] [Manufacturing method example 1] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), Atomic Layer Deposition (ALD), etc.

[0322] In addition, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed using wet deposition methods such as spin coating, dipping, spraying, inkjet, dispenser, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating or doctor knife coating.

[0323] In addition, when processing a thin film constituting the display device, it is possible to perform processing using, for example, photolithography.

[0324] In the photolithography method, as the light used for exposure, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm) or a mixture of these lights can be used. In addition, ultraviolet light, KrF laser or ArF laser, etc. can also be used. In addition, exposure can also be performed using liquid immersion exposure technology. In addition, as the light used for exposure, extreme ultraviolet (EUV: Extreme Ultra-violet) light or X-rays can also be used. In addition, instead of the light used for exposure, an electron beam can also be used.

[0325] For etching of the thin film, dry etching, wet etching, sand blasting, or the like can be used.

[0326] First, if Figure 4A As shown in the figure, an insulating layer 171 is formed on a substrate (not shown). Then, a conductive layer 172 and a conductive layer 179 are formed on the insulating layer 171, and an insulating layer 173 is formed on the insulating layer 171 so as to cover the conductive layer 172 and the conductive layer 179. Then, an insulating layer 174 is formed on the insulating layer 173, and an insulating layer 175 is formed on the insulating layer 174.

[0327] As the substrate, a substrate having heat resistance at least enough to withstand the subsequent heat treatment can be used. For example, 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 or silicon carbide, a compound semiconductor substrate such as silicon germanium, an SOI substrate, etc. can be used.

[0328] Then, if Figure 4A As shown in FIG. 1 , openings reaching the conductive layer 172 are formed in the insulating layer 175, the insulating layer 174, and the insulating layer 173. Next, the plug 176 is formed so as to be embedded in the opening.

[0329] Then, if Figure 4A As shown in FIG. 1 , a conductive film 151f, which will later become the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, and the conductive layer 151C, is formed on the plug 176 and the insulating layer 175. As the conductive film 151f, for example, a metal material can be used.

[0330] Then, if Figure 4A As shown in FIG. 1 , a resist mask 191 is formed on the conductive film 151f. The resist mask 191 can be formed by applying a photosensitive material (photoresist), exposing it to light, and developing it.

[0331] Then, if Figure 4B As shown, for example, the conductive film 151f is removed in a region that does not overlap with the resist mask 191. Thus, the conductive layer 151 is formed.

[0332] Then, if Figure 4C As shown, the resist mask 191 is removed. The resist mask 191 can be removed by ashing using oxygen plasma, for example.

[0333] Then, if Figure 4D As shown, an insulating film 156f, which will later become the insulating layer 156R, the insulating layer 156G, the insulating layer 156B and the insulating layer 156C, is formed on the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, the conductive layer 151C and the insulating layer 175.

[0334] The insulating film 156f can be formed using an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film. For example, silicon oxynitride can be used.

[0335] Then, if Figure 4E As shown, by processing the insulating film 156f, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B and the insulating layer 156C are formed.

[0336] Then, if Figure 5A As shown, a conductive film 152f is formed on the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, the conductive layer 151C, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, the insulating layer 156C and the insulating layer 175.

[0337] As the conductive film 152f, for example, a conductive oxide can be used. The conductive film 152f can also have a stacked-layer structure.

[0338] Then, if Figure 5B As shown, the conductive film 152f is processed to form a conductive layer 152R, a conductive layer 152G, a conductive layer 152B and a conductive layer 152C.

[0339] Then, if Figure 5C As shown in FIG. 1 , the organic compound film 103Rf is formed on the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the insulating layer 175. Figure 5C As shown, the organic compound film 103Rf is not formed on the conductive layer 152C.

[0340] Then, if Figure 5C As shown, a sacrificial film 158Rf and a mask film 159Rf are formed.

[0341] By providing the sacrificial film 158Rf on 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 improved.

[0342] The sacrificial film 158Rf is a film having high resistance to the processing conditions of the organic compound film 103Rf, specifically, a film having a large etching selectivity ratio with the organic compound film 103Rf. The mask film 159Rf is a film having a large etching selectivity ratio with the sacrificial film 158Rf.

[0343] In addition, the sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the heat resistance temperature of the organic compound film 103Rf. The substrate temperature when forming the sacrificial film 158Rf and the mask film 159Rf is typically 100° C. to 200° C., preferably 100° C. to 150° C., and more preferably 100° C. to 120° C.

[0344] As the sacrificial film 158Rf and the mask film 159Rf, a film that can be removed by a wet etching method or a dry etching method is preferably used.

[0345] The sacrificial film 158Rf formed in contact with the organic compound film 103Rf is preferably formed by a formation method that causes less damage to the organic compound film 103Rf than the mask film 159Rf. For example, ALD (Atomic Layer Deposition) or vacuum evaporation is more preferable than sputtering.

[0346] As 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.

[0347] As the sacrificial film 158Rf and the mask film 159Rf, for example, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing the metal materials can be used. In particular, low melting point materials such as aluminum and silver are preferably used. By using a metal material that can shield ultraviolet rays as one or both of the sacrificial film 158Rf and the mask film 159Rf, it is possible to suppress ultraviolet rays from irradiating the organic compound film 103Rf during pattern exposure and suppress the degradation of the organic compound film 103Rf, which is preferred.

[0348] In addition, as the sacrificial film 158Rf and the mask film 159Rf, metal oxides such as In-Ga-Zn oxide, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), indium tin oxide containing silicon, etc. can be used respectively.

[0349] Note that element M (M is one or more of aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten and magnesium) can also be used in the above-mentioned metal oxides instead of the above-mentioned gallium.

[0350] For example, it is preferable to use a semiconductor material such as silicon or germanium as the sacrificial film 158Rf and the mask film 159Rf because this material has high affinity with the semiconductor manufacturing process. Alternatively, a compound containing the above semiconductor material may be used.

[0351] Various inorganic insulating films can be used as the sacrificial film 158Rf and the mask film 159Rf, respectively. In particular, an oxide insulating film is preferred because it has higher adhesion to the organic compound film 103Rf than a nitride insulating film.

[0352] Then, if Figure 5C As shown, a resist mask 190R is formed. The resist mask 190R can be formed by applying a photosensitive resin (photoresist), exposing and developing the photosensitive resin.

[0353] Resist mask 190R is provided at a position overlapping conductive layer 152R. Resist mask 190R is preferably provided also at a position overlapping conductive layer 152C. This can prevent conductive layer 152C from being damaged during the manufacturing process of the display device.

[0354] Then, if Figure 5D As shown, a portion of the mask film 159Rf is removed using the resist mask 190R to form a mask layer 159R. The mask layer 159R remains on the conductive layer 152R and the conductive layer 152C. Then, the resist mask 190R is removed. Next, a portion of the sacrificial film 158Rf is removed using the mask layer 159R as a mask (also referred to as a hard mask) to form a sacrificial layer 158R.

[0355] By using the wet etching method, the damage to the organic compound film 103Rf during the processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced compared to the case of using the dry etching method. When the wet etching method is used, for example, it is preferable to use a developer, an alkali aqueous solution such as a tetramethylammonium hydroxide (TMAH) aqueous solution, an acid aqueous solution such as a chemical solution of dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed liquid thereof.

[0356] In addition, when dry etching is used in processing the sacrificial film 158Rf, degradation of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as an etching gas.

[0357] The resist mask 190R can be removed by the same method as the resist mask 191 .

[0358] Then, if Figure 5D As shown, the organic compound film 103Rf is processed to form the organic compound layer 103R. For example, the organic compound layer 103R is formed by removing a portion of the organic compound film 103Rf using the mask layer 159R and the sacrifice layer 158R as a hard mask.

[0359] Therefore, if Figure 5D As shown in FIG. 1 , the stacked structure of the organic compound layer 103R, the sacrificial layer 158R, and the mask layer 159R remains on the conductive layer 152R. In addition, the conductive layer 152G and the conductive layer 152B are exposed.

[0360] The processing of the organic compound film 103Rf is preferably performed using anisotropic etching, and anisotropic dry etching is particularly preferred. Alternatively, wet etching may be used.

[0361] When the dry etching method is used, by not using an oxygen-containing gas as an etching gas, degradation of the organic compound film 103Rf can be suppressed.

[0362] In addition, an oxygen-containing gas may 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 sufficient etching rate. Therefore, damage to the organic compound film 103Rf can be suppressed. In addition, defects such as adhesion of reaction products generated during etching can be suppressed.

[0363] When using the dry etching method, for example, it is preferred to use a gas containing one or more of the 18th group elements such as H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, He, Ar as the etching gas. Alternatively, it is preferred to use a gas containing one or more of the above gases and oxygen as the etching gas. Alternatively, oxygen gas may be used as the etching gas.

[0364] Then, if Fig. 6A As shown, an organic compound film 103Gf which will later become an organic compound layer 103G is formed.

[0365] The organic compound film 103Gf can be formed using the same method as that which can be used for forming the organic compound film 103Rf. In addition, the organic compound film 103Gf can have the same structure as that of the organic compound film 103Rf.

[0366] Then, if Fig. 6AAs shown, a sacrificial film 158Gf and a mask film 159Gf are sequentially formed. Then, a resist mask 190G is formed. The materials and forming methods of the sacrificial film 158Gf and the mask film 159Gf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and forming methods of the resist mask 190G are the same as those applicable to the resist mask 190R.

[0367] The resist mask 190G is provided at a position overlapping with the conductive layer 152G.

[0368] Then, if Figure 6B As shown in FIG. 1 , a portion of the mask film 159Gf is removed using the resist mask 190G, thereby forming a mask layer 159G. The mask layer 159G remains on the conductive layer 152G. Then, the resist mask 190G is removed. Next, using the mask layer 159G as a mask, a portion of the sacrificial film 158Gf is removed, thereby forming a sacrificial layer 158G. Next, the organic compound film 103Gf is processed to form an organic compound layer 103G. Thus, as shown in FIG. Figure 6B As shown in FIG. 1 , a stacked structure of the organic compound layer 103G, the sacrificial layer 158G, and the mask layer 159G remains on the conductive layer 152G. In addition, the mask layer 159R and the conductive layer 152B are exposed.

[0369] Then, if Figure 6C As shown, an organic compound film 103Bf is formed.

[0370] The organic compound film 103Bf can be formed using the same method as that which can be used for forming the organic compound film 103Rf. In addition, the organic compound film 103Bf can have the same structure as that of the organic compound film 103Rf.

[0371] Then, if Figure 6C As shown, a sacrificial film 158Bf and a mask film 159Bf are sequentially formed. Then, a resist mask 190B is formed. The materials and forming methods of the sacrificial film 158Bf and the mask film 159Bf are the same as those that can be used for the sacrificial film 158Rf and the mask film 159Rf. The materials and forming methods of the resist mask 190B are the same as those that can be used for the resist mask 190R.

[0372] The resist mask 190B is provided at a position overlapping with the conductive layer 152B.

[0373] Then, if Fig.6DAs shown, a portion of the mask film 159Bf is removed using the resist mask 190B, thereby forming the mask layer 159B. The mask layer 159B remains on the conductive layer 152B. Then, the resist mask 190B is removed. Next, using the mask layer 159B as a mask, a portion of the sacrificial film 158Bf is removed, thereby forming the sacrificial layer 158B. Next, the organic compound film 103Bf is processed to form the organic compound layer 103B. For example, using the mask layer 159B and the sacrificial layer 158B as a hard mask, a portion of the organic compound film 103Bf is removed, thereby forming the organic compound layer 103B.

[0374] Therefore, if Fig.6D As shown, the stacked structure of the organic compound layer 103B, the sacrificial layer 158B, and the mask layer 159B remains on the conductive layer 152B. In addition, the mask layer 159R and the mask layer 159G are exposed.

[0375] Note that the side surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are each preferably perpendicular or substantially perpendicular to the formed surface. For example, the angle formed by the formed surface and these side surfaces is preferably not less than 60 degrees and not more than 90 degrees.

[0376] As described above, the distance between two adjacent organic compound layers in the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B formed using the photolithography method can be reduced to less than 8 μm, less than 5 μm, less than 3 μm, less than 2 μm, or less than 1 μm. Here, for example, the distance can be specified according to the distance between the opposite ends of the two adjacent organic compound layers in the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. In this way, by reducing the distance between the island-shaped organic compound layers, a display device with high clarity and a large aperture ratio can be provided. In addition, the distance between the first electrodes of adjacent light-emitting devices can be reduced, for example, to less than 10 μm, less than 8 μm, less than 5 μm, less than 3 μm, or less than 2 μm. In addition, the distance between the first electrodes of adjacent light-emitting devices is preferably greater than 2 μm and less than 5 μm.

[0377] Then, if Fig. 7A As shown, mask layer 159R, mask layer 159G and mask layer 159B are preferably removed.

[0378] The mask layer can be removed by the same method as the mask film processing method. In particular, wet etching can reduce damage to the organic compound layer 103 when the mask layer is removed, compared with dry etching.

[0379] Alternatively, the mask layer may be removed by dissolving it in a polar solvent such as water or alcohol. Examples of the alcohol include ethanol, methanol, isopropyl alcohol (IPA), and glycerin.

[0380] After removing the mask layer, a drying treatment may be performed to remove surface water. For example, a heat treatment may be performed in an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment may be performed at a substrate temperature of 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 120°C. By adopting a reduced pressure atmosphere, drying can be performed at a lower temperature, so it is preferred.

[0381] Then, if Figure 7B As shown, an inorganic insulating film 125f is formed.

[0382] Then, if Figure 7C As shown in FIG. 1 , an insulating film 127 f which will later become an insulating layer 127 is formed on the inorganic insulating film 125 f.

[0383] The substrate temperature when forming the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower.

[0384] As the inorganic insulating film 125f, it is preferable to form an insulating film with a thickness of 3 nm, 5 nm or 10 nm and 200 nm, 150 nm, 100 nm or 50 nm within the above-mentioned substrate temperature range.

[0385] The inorganic insulating film 125f is preferably formed by, for example, the ALD method. The ALD method is preferred because it can reduce deposition damage and deposit a film with high coverage. As the inorganic insulating film 125f, for example, an aluminum oxide film is preferably formed by the ALD method.

[0386] The insulating film 127f is preferably formed by the wet deposition method described above. The insulating film 127f is preferably formed by, for example, a photosensitive material by spin coating, and more specifically, is preferably formed by using a photosensitive resin composition containing an acrylic resin.

[0387] Next, exposure is performed to sensitize a portion of the insulating film 127f with visible light or ultraviolet light. The insulating layer 127 is formed in a region sandwiched between any two of the conductive layer 152R, the conductive layer 152G, and the conductive layer 152B and around the conductive layer 152C.

[0388] The width of the insulating layer 127 to be formed later can be controlled by the region in which the insulating film 127f is exposed. In this embodiment, the insulating layer 127 is processed so that the insulating layer 127 has a portion overlapping with the top surface of the conductive layer 151.

[0389] The light used for exposure preferably includes i-line (wavelength: 365 nm). Alternatively, the light used for exposure may include at least one of g-line (wavelength: 436 nm) and h-line (wavelength: 405 nm).

[0390] Then, if Fig. 8A As shown, development is performed to remove the exposed region in the insulating film 127f, thereby forming the insulating layer 127a.

[0391] Then, if Figure 8B As shown, the insulating layer 127a is used as a mask to perform etching to remove a portion of the inorganic insulating film 125f, thereby reducing the thickness of a portion of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. As a result, the inorganic insulating layer 125 is formed under the insulating layer 127a. In addition, the surface of the thin portion of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B is exposed. Hereinafter, the etching process using the insulating layer 127a as a mask is sometimes referred to as the first etching process.

[0392] The first etching process can be performed by dry etching or wet etching. When the inorganic insulating film 125f is deposited using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the first etching process can be performed at once, which is preferable.

[0393] When dry etching is performed, chlorine-based gas is preferably used. As the chlorine-based gas, one gas selected from Cl2, BCl3, SiCl4, and CCl4, or a mixture of two or more of the above gases, can be used. In addition, one gas selected from oxygen gas, hydrogen gas, helium gas, and argon gas, or a mixture of two or more of the above gases can be appropriately added to the above chlorine-based gas. By utilizing dry etching, thin regions of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B can be formed with excellent in-plane uniformity.

[0394] As a dry etching device, a dry etching device having a high-density plasma source can be used. As a dry etching device having a high-density plasma source, for example, an inductively coupled plasma (ICP: Inductively Coupled Plasma) etching device can be used. Alternatively, a capacitively coupled plasma (CCP: Capacitively Coupled Plasma) etching device including parallel plate electrodes can be used.

[0395] In addition, it is preferred to perform the first etching treatment using wet etching. By using the wet etching method, the damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced compared to the case of using the dry etching method. For example, wet etching can be performed using an alkaline solution. For example, TMAH can be used as an alkaline solution in the wet etching of an aluminum oxide film. In addition, an acidic solution containing a fluoride can also be used. In this case, wet etching can be performed in a glue coating manner. When the inorganic insulating film 125f is deposited using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the above-mentioned etching treatment can be performed at one time, so it is preferred.

[0396] In the first etching process, the sacrificial layers 158R, 158G, and 158B are not completely removed, and the etching process is stopped in a state where the thickness is reduced. In this way, by leaving the corresponding sacrificial layers 158R, 158G, and 158B on the organic compound layers 103R, 103G, and 103B, the organic compound layers 103R, 103G, and 103B can be prevented from being damaged in the subsequent process.

[0397] Next, the entire substrate is preferably exposed to visible light or ultraviolet light to irradiate the insulating layer 127a. The energy density of this exposure is preferably greater than 0 mJ / cm 2 And 800mJ / cm 2 Below, more preferably greater than 0 mJ / cm 2 And 500mJ / cm 2 By performing such exposure after development, the transparency of the insulating layer 127a can be improved. In addition, the substrate temperature required for heat treatment in a later step for deforming the insulating layer 127a into a tapered shape can be reduced.

[0398] Here, by providing an insulating layer that blocks oxygen (for example, an aluminum oxide film) as the sacrificial layers 158R, 158G, and 158B, diffusion of hydrogen into the organic compound layers 103R, 103G, and 103B can be reduced.

[0399] Next, a heat treatment (also called post-baking) is performed. By performing the heat treatment, the insulating layer 127a can be deformed into an insulating layer 127 having a tapered shape on its side. Figure 8C). The heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layer. The heat treatment can be performed at a substrate temperature of 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 130°C. The heating atmosphere can be either an air atmosphere or an inert gas atmosphere. In addition, the heating atmosphere can be either an air atmosphere or a reduced pressure atmosphere. Thus, the adhesion between the insulating layer 127 and the inorganic insulating layer 125 can be improved, and the corrosion resistance of the insulating layer 127 can also be improved.

[0400] In the first etching process, the sacrificial layers 158R, 158G, and 158B are not completely removed, but the sacrificial layers 158R, 158G, and 158B are left in a thin state, so that the organic compound layers 103R, 103G, and 103B can be prevented from being damaged and deteriorated during the heat treatment. Thus, the reliability of the light-emitting device can be improved.

[0401] Then, if Fig. 9A As shown in FIG. 1 , etching is performed using the insulating layer 127 as a mask to remove a portion of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. Thus, an opening is formed in each of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, and the top surfaces of the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, and the conductive layer 152C are exposed. Note that this etching process may be referred to as a second etching process hereinafter.

[0402] The end of the inorganic insulating layer 125 is covered with the insulating layer 127. Fig. 9A An example is shown in which a portion of the end portion of the sacrificial layer 158G (specifically, the tapered portion formed by the first etching process) is covered with the insulating layer 127 and the tapered portion formed by the second etching process is exposed.

[0403] In addition, the second etching process is performed by wet etching. By using the wet etching method, the damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced compared with the case of using the dry etching method. For example, the wet etching can be performed using an alkaline solution or an acidic solution. In order to prevent the organic compound layer 103 from dissolving, the wet etching is preferably performed using an aqueous solution.

[0404] Then, if Fig. 9BAs shown in FIG. 3 , a common electrode 155 is formed on the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, the conductive layer 152C, and the insulating layer 127. The common electrode 155 can be formed by a method such as a sputtering method or a vacuum evaporation method. At this time, as shown in FIG. 3 , the organic compound layer 103 may be formed into a stacked-layer structure of the first EL layer 104 and the second EL layer 105, and the common electrode 155 may be formed thereon.

[0405] Then, if Fig. 9C As shown, a protective layer 131 is formed on the common electrode 155. The protective layer 131 can be formed by vacuum evaporation, sputtering, CVD, ALD or the like.

[0406] Next, the substrate 120 is bonded to the protective layer 131 using the resin layer 122, whereby a display device can be manufactured. As described above, in the method for manufacturing a display device according to one embodiment of the present invention, the insulating layer 156 is provided so as to include a region overlapping with the side surface of the conductive layer 151, and the conductive layer 152 is formed so as to cover the conductive layer 151 and the insulating layer 156. Thus, the yield of the display device can be improved, and the occurrence of defects can be suppressed.

[0407] As described above, in a method for manufacturing a display device of one formula of the present invention, the island-shaped organic compound layer 103R, the island-shaped organic compound layer 103G, and the island-shaped organic compound layer 103B are not formed using a high-precision metal mask but are formed by depositing a film on one surface and then processing it, so the island-shaped layer can be formed with a uniform thickness. In addition, a high-definition display device or a display device with a high aperture ratio can be realized. In addition, even if the clarity or aperture ratio is high and the distance between sub-pixels is extremely short, the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be prevented from contacting each other in adjacent sub-pixels. Therefore, leakage current can be suppressed between sub-pixels. Thus, crosstalk can be prevented to realize a display device with extremely high contrast.

[0408] In addition, even in a display device having a tandem light-emitting device manufactured using a photolithography method, a light-emitting device having high moisture resistance, high water resistance, high oxygen resistance, and high chemical resistance, low driving voltage, and high light-emitting efficiency can be provided.

[0409] Implementation 4 In this embodiment, a display device which is one embodiment of the present invention is described.

[0410] The display device of this embodiment can be a high-definition display device. Therefore, for example, the display device of this embodiment can be used as a display unit of information terminal devices (wearable devices) such as watch-type and bracelet-type devices, and a display unit of wearable devices that can be worn on the head such as VR devices such as head-mounted displays (HMDs) and glasses-type AR devices.

[0411] In addition, the display device of this embodiment can be a high-resolution display device or a large display device. Therefore, for example, the display device of this embodiment can be used as a display portion of the following devices: electronic devices with large screens such as television devices, desktop or notebook personal computers, displays for computers, etc., digital signage and large game machines such as pinball machines, etc.; digital cameras; digital video cameras; digital photo frames; mobile phones; portable game consoles; portable information terminals; and sound reproduction devices.

[0412] [Display module] Fig. 10A 2 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 included in the display module 280 is not limited to the display device 100A, and may be any of the display device 100B and the display device 100E to be described later.

[0413] The display module 280 includes a substrate 291 and a substrate 292. The display module 280 includes a display portion 281. The display portion 281 is an image display region in the display module 280, and light from each pixel provided in a pixel portion 284 described below can be viewed.

[0414] Fig. 10B 2 is a perspective view of a structure on one side of a substrate 291. A circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked on the substrate 291. In addition, a terminal portion 285 for connecting to the FPC 290 is provided on a portion of the substrate 291 that is not overlapped by the pixel portion 284. The terminal portion 285 is electrically connected to the circuit portion 282 via a wiring portion 286 composed of a plurality of wirings.

[0415] The pixel portion 284 includes a plurality of pixels 284 a arranged periodically. Fig. 10B An enlarged view of one pixel 284a is shown on the right side of FIG. The pixel 284a can adopt the various structures described in the above embodiment. Fig. 10B An example is shown in which the pixel 284 a has the same structure as the pixel 178 shown in FIG. 3 .

[0416] The pixel circuit portion 283 includes a plurality of pixel circuits 283 a arranged periodically.

[0417] One pixel circuit 283a controls driving of a plurality of elements included in one pixel 284a.

[0418] The circuit unit 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit unit 283. For example, it preferably includes one or both of a gate line driving circuit and a source line driving circuit. In addition, it may include at least one of a calculation circuit, a storage circuit, and a power supply circuit.

[0419] The FPC 290 is used as wiring for supplying video signals, power supply potential, and the like from the outside to the circuit portion 282. Alternatively, an IC may be mounted on the FPC 290.

[0420] The display module 280 may have a structure in which one or both of the pixel circuit portion 283 and the circuit portion 282 are stacked on the lower side of the pixel portion 284 , so that the display portion 281 may have an extremely high aperture ratio (effective display area ratio).

[0421] This high-definition display module 280 is suitable for use in VR devices such as HMD or glasses-type AR devices. For example, because the display module 280 has a very high-definition display unit 281, in a structure where the display unit of the display module 280 is viewed through a lens, even if the display unit is magnified by the lens, the user cannot see the pixels, thereby achieving a highly immersive display. In addition, the display module 280 can also be applied to electronic devices with a relatively small display unit.

[0422] [Display device 100A] Fig.11A The display device 100A shown includes a substrate 301 , a light emitting device 130R, a light emitting device 130G, a light emitting device 130B, a capacitor 240 , and a transistor 310 .

[0423] Substrate 301 is equivalent to Fig. 10A and Fig. 10B The transistor 310 is a transistor having a channel formation region in the substrate 301. As the substrate 301, for example, a semiconductor substrate such as a single crystal silicon substrate can be used. The transistor 310 includes a portion 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 is used as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and is used as a gate insulating layer. The low resistance region 312 is a region doped with impurities in the substrate 301 and is used as a source or a drain. The insulating layer 314 covers the side of the conductive layer 311.

[0424] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0425] In addition, an insulating layer 261 is provided to cover the transistor 310 , and the capacitor 240 is provided over the insulating layer 261 .

[0426] Capacitor 240 includes conductive layer 241, conductive layer 245, and insulating layer 243 therebetween. Conductive layer 241 serves as one electrode in capacitor 240, conductive layer 245 serves as the other electrode in capacitor 240, and insulating layer 243 serves as a dielectric of capacitor 240.

[0427] The conductive layer 241 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and the drain of the transistor 310 through the plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided in a manner covering the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 via the insulating layer 243.

[0428] An insulating layer 255 is provided to cover the capacitor 240, an insulating layer 174 is provided on the insulating layer 255, and an insulating layer 175 is provided on the insulating layer 174. The light emitting devices 130R, 130G, and 130B are provided on the insulating layer 175. An insulator is provided in a region between adjacent light emitting devices.

[0429] The insulating layer 156R is provided so as to include a region overlapping with the side surface of the conductive layer 151R, the insulating layer 156G is provided so as to include a region overlapping with the side surface of the conductive layer 151G, and the insulating layer 156B is provided so as to include a region overlapping with the side surface of the conductive layer 151B. Furthermore, the conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R, the conductive layer 152G is provided so as to cover the conductive layer 151G and the insulating layer 156G, and the conductive layer 152B is provided so as to cover the conductive layer 151B and the insulating layer 156B. The sacrificial layer 158R is located on the organic compound layer 103R, the sacrificial layer 158G is located on the organic compound layer 103G, and the sacrificial layer 158B is located on the organic compound layer 103B.

[0430] The conductive layers 151R, 151G, and 151B are electrically connected to one of the source and the drain of the transistor 310 via the plugs 256 embedded in the insulating layers 243, 255, 174, and 175, the conductive layer 241 embedded in the insulating layer 254, and the plug 271 embedded in the insulating layer 261. Various conductive materials can be used for the plugs.

[0431] In addition, a protective layer 131 is provided on the light emitting device 130R, the light emitting device 130G, and the light emitting device 130B. The substrate 120 is bonded to the protective layer 131 by the resin layer 122. The details of the components of the light emitting device 130 to the substrate 120 can be referred to Embodiment 3. The substrate 120 corresponds to Fig. 10A substrate 292.

[0432] Fig. 11B Show Fig.11A A modified example of the display device 100A shown. Fig. 11B The display device shown includes a coloring layer 132R, a coloring layer 132G, and a coloring layer 132B, and the light emitting device 130 has a region overlapping one of the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B. Fig. 11B In the display device shown, the light emitting device 130 can emit white light, for example. In addition, for example, the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B can transmit red light, green light, and blue light, respectively.

[0433] [Display device 100B] Fig.12 A perspective view of the display device 100B is shown.

[0434] The display device 100B has a structure in which a substrate 352 and a substrate 351 are bonded together. Fig.12 In FIG. 3 , the substrate 352 is indicated by a dotted line.

[0435] The display device 100B includes a pixel portion 177 , a connection portion 140 , a circuit 356 , a wiring 355 , and the like. Fig.12 FIG. 1 shows an example in which the display device 100B is equipped with the IC 354 and the FPC 353. Fig.12 The structure shown is called a display module including the display device 100B, IC (integrated circuit) and FPC. Here, the substrate of the display device with a connector such as FPC mounted thereon or the substrate with IC mounted thereon is called a display module.

[0436] The connection part 140 is disposed outside the pixel part 177. There may be one or more connection parts 140. In the connection part 140, the common electrode of the light emitting device is electrically connected to the conductive layer, and power can be supplied to the common electrode.

[0437] As the circuit 356, for example, a scan line driver circuit can be used.

[0438] The wiring 355 has a function of supplying a signal and power to the pixel portion 177 and the circuit 356. The signal and power are input to the wiring 355 from the outside through the FPC 353 or are input to the wiring 355 from the IC 354.

[0439] Fig.12 An example of providing IC354 on substrate 351 by COG (Chip On Glass) method or COF (Chip on Film) method is shown. As IC354, for example, an IC including a scanning line driving circuit or a signal line driving circuit can be used. Note that the display device 100B and the display module do not necessarily have to be provided with an IC. In addition, for example, the IC can also be mounted on an FPC by using a COF method.

[0440] Fig.13 An example of a cross section of a portion of the region including the FPC 353 , a portion of the circuit 356 , a portion of the pixel portion 177 , a portion of the connection portion 140 , and a portion of the region including the end portion of the display device 100B is shown.

[0441] [Display device 100C] Fig.13 The display device 100C shown includes a transistor 201 , a transistor 205 , a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, a light-emitting device 130B that emits blue light, and the like between a substrate 351 and a substrate 352 .

[0442] The details of the light emitting device 130R, the light emitting device 130G, and the light emitting device 130B may be referred to Embodiment 1 to Embodiment 3.

[0443] The light emitting device 130R includes a conductive layer 224R, a conductive layer 151R on the conductive layer 224R, and a conductive layer 152R on the conductive layer 151R. The light emitting device 130G includes a conductive layer 224G, a conductive layer 151G on the conductive layer 224G, and a conductive layer 152G on the conductive layer 151G. The light emitting device 130B includes a conductive layer 224B, a conductive layer 151B on the conductive layer 224B, and a conductive layer 152B on the conductive layer 151B.

[0444] The conductive layer 224R is connected to the conductive layer 222b included in the transistor 205 through an opening provided in the insulating layer 214. An end of the conductive layer 151R is located outside an end of the conductive layer 224R. The insulating layer 156R is provided so as to include a region in contact with a side surface of the conductive layer 151R, and the conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R.

[0445] The conductive layer 224G, conductive layer 151G, conductive layer 152G, and insulating layer 156G in the light-emitting device 130G and the conductive layer 224B, conductive layer 151B, conductive layer 152B, and insulating layer 156B in the light-emitting device 130B are the same as the conductive layer 224R, conductive layer 151R, conductive layer 152R, and insulating layer 156R in the light-emitting device 130R, so detailed description is omitted.

[0446] Concave portions are formed in conductive layer 224R, conductive layer 224G, and conductive layer 224B so as to cover the openings provided in insulating layer 214. The concave portions are filled with layer 128.

[0447] The layer 128 has the function of flattening the concave portions of the conductive layers 224R, 224G, and 224B. The conductive layers 151R, 151G, and 151B electrically connected to the conductive layers 224R, 224G, and 224B are provided on the conductive layers 224R, 224G, and 224B, and the layer 128. Therefore, the region overlapping the concave portions of the conductive layers 224R, 224G, and 224B can also be used as a light-emitting region, and the aperture ratio of the pixel can be increased.

[0448] Layer 128 may be an insulating layer or a conductive layer. Layer 128 may be formed of various inorganic insulating materials, organic insulating materials, and conductive materials as appropriate. In particular, layer 128 is preferably formed of an insulating material, and more preferably formed of an organic insulating material. Layer 128 may be formed of, for example, the organic insulating material that can be used for insulating layer 127.

[0449] A protective layer 131 is provided on 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 bonded by an adhesive layer 142. The substrate 352 is provided with a light shielding layer 157. The sealing of the light emitting device 130 may adopt a solid sealing structure or a hollow sealing structure. Fig.13 In the embodiment, the space between the substrate 352 and the substrate 351 is filled with the adhesive layer 142, that is, a solid sealing structure is adopted. Alternatively, the space may be filled with an inert gas (nitrogen or argon, etc.), that is, a hollow sealing structure is adopted. In this case, the adhesive layer 142 may also be arranged in a manner that does not overlap with the light-emitting device. In addition, a resin different from the adhesive layer 142 arranged in a frame shape may be used to fill the space.

[0450] Fig.13The following example is shown: the connection portion 140 includes a conductive layer 224C processed from the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive layer 151C processed from the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive layer 152C processed from the same conductive film as the conductive layers 152R, 152G, and 152B. In addition, Fig.13 An example is shown in which the insulating layer 156C is provided so as to include a region overlapping with the side surface of the conductive layer 151C.

[0451] The display device 100B is a top emission type display device. The light emitting device emits light to the substrate 352 side. The substrate 352 preferably uses a material with high transmittance to visible light. When the light emitting device emits infrared light or near-infrared light, it is preferably used a material with high transmittance to them. The pixel electrode includes a material that reflects visible light, and the counter electrode (common electrode 155) includes a material that transmits visible light.

[0452] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are sequentially provided on the substrate 351. A portion of the insulating layer 211 is used as a gate insulating layer of each transistor. A portion of the insulating layer 213 is used as a gate insulating layer of each transistor. The insulating layer 215 is provided in a manner covering the transistor. The insulating layer 214 is provided in a manner covering the transistor and is used as a planarization layer. In addition, there is no particular limitation on the number of gate insulating layers and the number of insulating layers covering the transistor, and it can be one or more than two.

[0453] As the insulating layer 211 , the insulating layer 213 , and the insulating layer 215 , an inorganic insulating film is preferably used.

[0454] As the insulating layer 214 serving as a planarizing layer, an organic insulating layer is preferably used.

[0455] The transistor 201 and the transistor 205 include: a conductive layer 221 used as a gate; an insulating layer 211 used as a gate insulating layer; a conductive layer 222a and a conductive layer 222b used as a source and a drain; a semiconductor layer 231; an insulating layer 213 used as a gate insulating layer; and a conductive layer 223 used as a gate.

[0456] A connection portion 204 is provided in a region of the substrate 351 that is not overlapped by the substrate 352. In the connection portion 204, the source electrode or the drain electrode of the transistor 201 is electrically connected to the FPC 353 through the conductive layer 166 and the connection layer 242. The following example is shown: the conductive layer 166 has a laminated 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 the top surface of the connection portion 204. Therefore, the connection portion 204 can be electrically connected to the FPC 353 through the connection layer 242.

[0457] It is preferable to provide a light shielding layer 157 on the surface of the substrate 352 on the substrate 351 side. The light shielding layer 157 may be provided between adjacent light emitting devices, in the connection portion 140 and the circuit 356, etc. In addition, various optical members may be arranged outside the substrate 352.

[0458] The substrate 351 and the substrate 352 can each adopt a material that can be used for the substrate 120 .

[0459] As the adhesive layer 142 , a material that can be used for the resin layer 122 can be used.

[0460] As the connection layer 242 , an anisotropic conductive film (ACF: Anisotropic Conductive Film), anisotropic conductive paste (ACP: Anisotropic Conductive Paste), or the like can be used.

[0461] [Display device 100D] Fig.14 The display device 100D shown in FIG. Fig.13 The main difference of the illustrated display device 100C is that the display device 100D is a bottom emission type display device.

[0462] Light emitted by the light emitting device is emitted to the side of the substrate 351. It is preferable to use a material having high transmittance to visible light for the substrate 351. On the other hand, there is no limitation on the transmittance of the material used for the substrate 352.

[0463] A light shielding layer is preferably formed between the substrate 351 and the transistor 201 and between the substrate 351 and the transistor 205 . Fig.14 An example is shown in which a light-shielding layer 157 is provided over a substrate 351 , an insulating layer 153 is provided over the light-shielding layer, and transistors 201 , 205 , and the like are provided over the insulating layer 153 .

[0464] The light emitting device 130R includes a conductive layer 112R, a conductive layer 126R on the conductive layer 112R, and a conductive layer 129R on the conductive layer 126R.

[0465] The light emitting device 130B includes a conductive layer 112B, a conductive layer 126B on the conductive layer 112B, and a conductive layer 129B on the conductive layer 126B.

[0466] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are all made of a material having high transmittance to visible light. The common electrode 155 is preferably made of a material that reflects visible light.

[0467] Note that although Fig.14 Although the light emitting device 130G is not shown in the figure, the light emitting device 130G is also provided.

[0468] in addition, Fig.14 The example in which the top surface of the layer 128 has a flat portion is shown, but the shape of the layer 128 is not particularly limited.

[0469] [Display device 100E] Fig.15 The display device 100E shown is Fig.13 In the variation example of the display device 100C shown, the display device 100E is different from the display device 100C mainly in that the display device 100E includes a coloring layer 132R, a coloring layer 132G, and a coloring layer 132B.

[0470] In the display device 100E, the light emitting device 130 has a region overlapping one of the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B. The coloring layer 132R, the coloring layer 132G, and the coloring layer 132B may be provided on a surface of the substrate 352 on the substrate 351 side. An end portion of the coloring layer 132R, an end portion of the coloring layer 132G, and an end portion of the coloring layer 132B may overlap the light shielding layer 157.

[0471] In the display device 100E, the light emitting device 130 may emit white light, for example. In addition, for example, the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B may transmit red light, green light, and blue light, respectively. In addition, the display device 100E may also adopt a structure in which the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B are provided between the protective layer 131 and the adhesive layer 142.

[0472] Fig.13 and Fig.15 The example in which the top surface of the layer 128 has a flat portion is shown, but the shape of the layer 128 is not particularly limited.

[0473] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0474] Implementation method 5 In this embodiment, an electronic device which is one embodiment of the present invention is described.

[0475] The electronic device of this embodiment includes a display device of one embodiment of the present invention in a display unit. The display device of one embodiment of the present invention has high display performance and can easily achieve high definition and high resolution. Therefore, it can be used in the display unit of various electronic devices.

[0476] Electronic devices include, for example, television sets, desktop or notebook personal computers, displays for computers, etc., digital signage, large-scale game consoles such as pinball machines, and other electronic devices with larger screens, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, portable information terminals, sound reproduction devices, and the like.

[0477] In particular, since the display device of one embodiment of the present invention can improve the clarity, it can be suitably used in electronic devices including a smaller display unit. Examples of such electronic devices include watch-type and bracelet-type information terminal devices (wearable devices), wearable devices that can be worn on the head such as VR devices such as head-mounted displays, glasses-type AR devices, and MR devices.

[0478] The electronic device of this embodiment may also include a sensor (the sensor has the function of measuring the following factors: force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electricity, radiation, flow, humidity, inclination, vibration, smell or infrared).

[0479] Reference FIG. 16A to FIG. 16D An example of a wearable device that can be worn on the head is described.

[0480] Fig.16A The electronic device 700A shown and Fig. 16B The electronic devices 700B shown include a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical components 753, a frame 757 and a pair of nose pads 758.

[0481] The display device of one embodiment of the present invention can be applied to the display panel 751. Thus, a highly reliable electronic device can be realized.

[0482] Both electronic devices 700A and 700B can project the image displayed by display panel 751 onto display region 756 in optical member 753. Since optical member 753 is light-transmissive, the user can see the image displayed on the display region superimposed on the transmitted image seen through optical member 753.

[0483] The electronic device 700A and the electronic device 700B may also be provided with a camera capable of photographing the front as an imaging unit. In addition, by providing an acceleration sensor such as a gyro sensor on the electronic device 700A and the electronic device 700B, the user's head orientation can be detected and an image corresponding to the direction can be displayed on the display area 756.

[0484] The communication unit includes a wireless communication device, through which, for example, a video signal can be supplied. In addition, the communication unit may include a connector to which a cable for supplying the video signal and the power supply potential can be connected, instead of or in addition to the wireless communication device.

[0485] Furthermore, electronic device 700A and electronic device 700B are provided with batteries, and can be charged wirelessly or by wire, or both.

[0486] The housing 721 may also be provided with a touch sensor module.

[0487] As the touch sensor module, various touch sensors can be used. For example, various methods such as electrostatic capacitance, resistance film, infrared, electromagnetic induction, surface acoustic wave, and optical can be used. In particular, it is preferred to use electrostatic capacitance or optical sensors in the touch sensor module.

[0488] Fig. 16C The electronic device 800A shown and Fig.16D The electronic devices 800B shown each include a pair of display portions 820 , a housing 821 , a communication portion 822 , a pair of mounting portions 823 , a control portion 824 , a pair of imaging portions 825 , and a pair of lenses 832 .

[0489] The display device of one embodiment of the present invention can be applied to the display portion 820. This makes it possible to realize an electronic device with high reliability.

[0490] The display unit 820 is provided at a position visible through the lens 832 inside the housing 821. In addition, by displaying different images on each of the pair of display units 820, three-dimensional display using parallax can be performed.

[0491] The electronic device 800A and the electronic device 800B preferably have a mechanism that can adjust the left and right positions of the lens 832 and the display unit 820 so that the lens 832 and the display unit 820 are located at the most appropriate positions according to the position of the user's eyes.

[0492] The user can use the mounting portion 823 to mount the electronic device 800A or the electronic device 800B on the head.

[0493] The imaging unit 825 has a function of acquiring external information. The data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used in the imaging unit 825. In addition, a plurality of cameras can be provided to be able to correspond to various viewing angles such as telephoto and wide angle.

[0494] The electronic device 800A may also include a vibration mechanism for use as a bone conduction headset.

[0495] Electronic device 800A and electronic device 800B may both include input terminals. Cables for supplying video signals from a video output device or the like, power for charging a battery provided in the electronic device, and the like may be connected to the input terminals.

[0496] The electronic device according to one embodiment of the present invention may have a function of wirelessly communicating with the earphone 750 .

[0497] In addition, the electronic device may include an earphone unit. Fig. 16B The electronic device 700B shown includes an earphone unit 727. A part of the wiring connecting the earphone unit 727 and the control unit may be arranged inside the housing 721 or the mounting unit 723.

[0498] same, Fig.16D The electronic device 800B shown includes an earphone unit 827. For example, a structure in which the earphone unit 827 and the control unit 824 are connected in a wired manner may be adopted.

[0499] As described above, as electronic devices according to one embodiment of the present invention, both glasses-type (electronic devices 700A and 700B, etc.) and goggles-type (electronic devices 800A and 800B, etc.) are preferable.

[0500] Fig.17A The electronic device 6500 shown is a portable information terminal device that can be used as a smartphone.

[0501] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, a light source 6508, and the like. The display portion 6502 has a touch panel function.

[0502] The display device of one embodiment of the present invention can be used as the display portion 6502. Thus, a highly reliable electronic device can be achieved.

[0503] Fig. 17B 65 is a schematic cross-sectional view of an end portion of a housing 6501 on one side of a microphone 6506 .

[0504] A light-transmitting protective component 6510 is provided on the 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, etc. are provided in the space surrounded by the housing 6501 and the protective component 6510.

[0505] The display panel 6511 , the optical member 6512 , and the touch sensor panel 6513 are fixed to the protective member 6510 using an adhesive layer (not shown).

[0506] In a region outside the display portion 6502, a portion of the display panel 6511 is folded back, and the folded back portion is connected to an FPC 6515. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0507] The display panel 6511 can use a light-emitting device of one embodiment of the present invention. Thus, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be installed while suppressing the thickness of the electronic device. In addition, by folding a portion of the display panel 6511 to provide a connection portion with the FPC 6515 on the back of the pixel portion, an electronic device with a narrow frame can be realized.

[0508] Fig. 17C An example of a television set is shown. In a television set 7100, a display portion 7000 is incorporated in a housing 7171. Here, a structure in which the housing 7171 is supported by a stand 7173 is shown.

[0509] The display device of one embodiment of the present invention can be used as the display portion 7000. Thus, a highly reliable electronic device can be realized.

[0510] The operation can be performed by using the operating switch provided in the housing 7171 and the remote control operating machine 7151 provided separately. Fig. 17C The operation of television device 7100 is shown.

[0511] Fig.17D1 shows an example of a notebook personal computer. The notebook personal computer 7200 includes a housing 7211 , a keyboard 7212 , a pointing device 7213 , an external connection port 7214 , and the like. A display portion 7000 is incorporated in the housing 7211 .

[0512] The display device of one embodiment of the present invention can be used as the display portion 7000. Thus, a highly reliable electronic device can be realized.

[0513] Fig.17E and Fig.17F An example of digital signage is shown.

[0514] Fig.17E The digital signage 7300 shown includes a housing 7301, a display unit 7000, a speaker 7303, etc. In addition, an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, etc. may be included.

[0515] Fig.17F The digital signage 7400 is shown to be disposed on a cylindrical pillar 7401. The digital signage 7400 includes a display unit 7000 disposed along a curved surface of the pillar 7401.

[0516] exist Fig.17E and Fig.17F In the embodiment of the present invention, the display device according to one embodiment of the present invention can be used for the display portion 7000. Thus, a highly reliable electronic device can be achieved.

[0517] The larger the display unit 7000 is, the more information can be provided at one time. The larger the display unit 7000 is, the easier it is to attract people's attention, for example, the advertising effect can be improved.

[0518] like Fig.17E and Fig.17F As shown, the digital signage 7300 or the digital signage 7400 can preferably be linked with the information terminal device 7311 or the information terminal device 7411 such as a smart phone carried by the user through wireless communication.

[0519] FIG. 18A to FIG. 18G The electronic device shown includes a housing 9000, a display portion 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connecting terminal 9006, a sensor 9007 (the sensor has the function of measuring the following factors: force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electricity, radiation, flow, humidity, inclination, vibration, smell or infrared), a microphone 9008, etc.

[0520] FIG. 18A to FIG. 18GThe electronic device shown has various functions. For example, it may have the following functions: a function of displaying various information (static images, dynamic images, text images, etc.) on a display unit; a function of a touch panel; a function of displaying a calendar, date, or time, etc.; a function of controlling processing by using various software (programs); a function of wireless communication; a function of reading out programs or data stored in a storage medium and processing them; etc.

[0521] Below, we explain in detail FIG. 18A to FIG. 18G Electronic equipment shown.

[0522] Fig.18A 9171 is a perspective view showing a portable information terminal 9171. The portable information terminal 9171 can be used as a smart phone, for example. Note that a speaker 9003, a connection terminal 9006, a sensor 9007, and the like can also be provided in the portable information terminal 9171. In addition, as the portable information terminal 9171, text or image information can be displayed on multiple surfaces. Fig.18A 9050. In addition, information 9051 indicated by a dotted rectangle may be displayed on another surface of the display unit 9001. Examples of information 9051 include information indicating that an email, SNS, or phone call has been received; a title of the email or SNS; a sender's name of the email or SNS; a date; a time; a remaining battery level; and radio wave strength. Alternatively, icon 9050 may be displayed at a location where information 9051 is displayed.

[0523] Fig.18B 9172. The portable information terminal 9172 has a function of displaying information on three or more surfaces of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, when the portable information terminal 9172 is placed in a jacket pocket, the user can check the information 9053 displayed at a position viewed from above the portable information terminal 9172.

[0524] Fig.18C 9173 is a perspective view showing a tablet terminal 9173. The tablet terminal 9173 can execute various application software such as mobile phone, reading and editing of e-mails and articles, playing music, network communication, computer games, etc. The tablet terminal 9173 includes a display portion 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the housing 9000, an operation key 9005 used as an operation button on the left side of the housing 9000, and a connection terminal 9006 on the bottom.

[0525] Fig.18D9001 is a stereoscopic diagram showing a watch-type portable information terminal 9200. The portable information terminal 9200 can be used, for example, as a smart watch (registered trademark). In addition, the display surface of the display unit 9001 is curved, and a display can be performed along its curved display surface. In addition, the portable information terminal 9200 can perform hands-free calls, for example, by communicating with a headset capable of wireless communication. In addition, by using the connection terminal 9006, the portable information terminal 9200 can perform data transmission or charging with other information terminals. Charging can also be performed by wireless power supply.

[0526] FIG. 18E to FIG. 18G 9201 is a perspective view showing a foldable portable information terminal. Fig.18E is a perspective view of the portable information terminal 9201 in an unfolded state. Figure 18G This is a three-dimensional diagram of the folded state. Fig.18F is from Fig.18E Status and Figure 18G The portable information terminal 9201 is easy to carry in the folded state, and has a large display area that is seamlessly spliced ​​in the unfolded state, so the display is easy to browse. The display unit 9001 included in the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. The display unit 9001 can be bent within a range of a curvature radius of 0.1 mm or more and 150 mm or less, for example.

[0527] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate. Example 1

[0528] In this embodiment, the detailed manufacturing method and characteristics of the light-emitting devices 1-1 to 1-8 of the tandem light-emitting devices using an organic compound (second organic compound) having electron transport properties with different LUMO energy levels as the first layer of the intermediate layer are described. The structural formulas of the main compounds used in this embodiment are shown below.

[0529] [Chemical formula 7]

[0530] [Chemical formula 8]

[0531] (Method for manufacturing light emitting device 1-1) First, silver (Ag) with a thickness of 100 nm as a reflective electrode and indium tin oxide (ITSO) with a thickness of 85 nm as a transparent electrode were deposited in sequence on a glass substrate from one side of the substrate by sputtering to form a first electrode 101 with a size of 2 mm×2 mm. The transparent electrode was used as an anode and was considered as the first electrode 101 in combination with the above-mentioned reflective electrode.

[0532] Next, as a pretreatment for forming a light-emitting device on the substrate, the surface of the substrate was washed with water and baked at 200° C. for 1 hour.

[0533] Then, the substrate is placed inside the chamber and the pressure is reduced to 1×10 -4 Pa in a vacuum evaporation equipment, and vacuum bake at a temperature of 170°C for 30 minutes in a heating chamber in the vacuum evaporation equipment, and then the substrate is cooled for about 30 minutes.

[0534] Next, the substrate is fixed on a bracket provided in a vacuum evaporation device in a manner such that the surface on which the first electrode 101 is formed faces downward, and N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviated as: PCBBiF) represented by the above structural formula (i) and a material having an electron acceptor property and containing fluorine and having a molecular weight of 672 (OCHD-003) are co-evaporated on the first electrode 101 by a method in a weight ratio of 1:0.03 (=PCBBiF:OCHD-003) and a thickness of 10 nm, thereby forming a hole injection layer 111.

[0535] PCBBiF was evaporated on the hole injection layer 111 to a thickness of 90 nm, thereby forming a first hole transport layer.

[0536] Next, on the first hole transport layer, 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as 8mpTP-4mDBtPBfpm) represented by the above structural formula (ii), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as βNCCP) represented by the above structural formula (iii) and [2-d3-methyl-8-(2-pyridin-2-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as 8mpTP-4mDBtPBfpm) represented by the above structural formula (iv) were added. The first light-emitting layer is formed by co-evaporation in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)) and a thickness of 40nm, wherein the first light-emitting layer is prepared by co-evaporation.

[0537] Then, 3,6-bis(diphenylamino)-9-[4-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9H-carbazole (abbreviation: DACT-II) represented by the above structural formula (v) was deposited to a thickness of 10 nm to form a first electron transport layer.

[0538] After forming the first electron transport layer, 1,1'-pyridine-2,6-diyl-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) (abbreviated as hpp2py) represented by the above structural formula (I) as the second organic compound and 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as Pyrrd-Phen) represented by the above structural formula (vi) as the first organic compound were mixed in a weight ratio of 0.5:0.5 (=hpp2py:Pyrrd-Phen ) and co-evaporated in a manner of 5 nm in thickness, then indium (In) was evaporated in a manner of 2 nm in thickness to form a layer that would become the first region, copper phthalocyanine (abbreviation: CuPc) represented by the above structural formula (vii) was evaporated in a manner of 2 nm in thickness to form a layer that would become the third region, and PCBBiF and OCHD-003 were co-evaporated in a manner of a weight ratio of 1:0.15 (=PCBBiF:OCHD-003) and a thickness of 10 nm to form a layer that would become the second region, thereby forming an intermediate layer.

[0539] PCBBiF was evaporated on the intermediate layer to a thickness of 55 nm, thereby forming a second hole transport layer.

[0540] On the second hole transport layer, 8mpTP-4mDBtPBfpm, βNCCP and Ir(5mppy-d3)2(mbfpypy-d3) were co-evaporated in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)) and a thickness of 40nm, thereby forming a second light-emitting layer.

[0541] Then, 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as: 2mPCCzPDBq) represented by the above structural formula (viii) is evaporated in a thickness of 20 nm, and 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as: mPPhen2P) represented by the above structural formula (ix) is evaporated in a thickness of 20 nm, thereby forming a second electron transport layer.

[0542] The sample formed up to the second electron transport layer was exposed to the air atmosphere for 1 hour. Then, the pressure inside was reduced to 1×10 -4 The vacuum baking was performed at 110° C. for 1 hour in a heating chamber in a vacuum deposition device at a pressure of about 1.5 psi.

[0543] Then, lithium fluoride (LiF) and ytterbium (Yb) are co-evaporated in a volume ratio of 1:0.5 and a thickness of 1.5 nm, and then silver (Ag) and magnesium (Mg) are co-evaporated in a volume ratio of 1:0.1 and a thickness of 15 nm to form the second electrode 102. In addition, 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as: DBT3P-II) represented by the above structural formula (x) is deposited as a cap layer in a thickness of 70 nm on the second electrode 102, thereby improving the light extraction efficiency.

[0544] Next, in a glove box with a nitrogen atmosphere, a sealing process is performed using a glass substrate in such a way that the light-emitting device is not exposed to the atmosphere (a UV-curing sealing material is applied around the device so that UV is not irradiated on the light-emitting device but only on the sealing material, and heat treatment is performed at 80°C under atmospheric pressure for 1 hour), thereby forming a light-emitting device 1-1.

[0545] (Method for manufacturing light emitting device 1-2) The light-emitting device 1-2 was manufactured in the same manner as the light-emitting device 1-1 except that hpp2Py (the second organic compound) in the light-emitting device 1-1 was replaced with mPPhen2P represented by the above structural formula (II).

[0546] (Method for manufacturing light emitting device 1-3) Light-emitting device 1-3 is manufactured in the same manner as light-emitting device 1-1 except that hpp2Py (the second organic compound) in light-emitting device 1-1 is replaced with 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth) represented by the above structural formula (III).

[0547] (Method for manufacturing light emitting device 1-4) Light-emitting device 1-4 is manufactured in the same manner as light-emitting device 1-1 except that hpp2Py (the second organic compound) in light-emitting device 1-1 is replaced with 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviated as: ZADN) represented by the above structural formula (IV).

[0548] (Method for manufacturing light emitting device 1-5) Light-emitting device 1-5 is manufactured in the same manner as light-emitting device 1-1 except that hpp2Py (the second organic compound) in light-emitting device 1-1 is replaced with 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviated as: mSiTrz) represented by the above structural formula (V).

[0549] (Method for manufacturing light emitting device 1-6) Light-emitting device 1-6 is manufactured in the same manner as light-emitting device 1-1 except that hpp2Py (the second organic compound) in light-emitting device 1-1 is replaced with 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviated as: mPn-mDMePyPTzn) represented by the above structural formula (VI).

[0550] (Method for manufacturing light emitting device 1-7) Light-emitting device 1-7 is manufactured in the same manner as light-emitting device 1-1 except that hpp2Py (the second organic compound) in light-emitting device 1-1 is replaced with 8mpTP-4mDBtPBfpm represented by the above structural formula (VII). Note that in light-emitting device 1-7, the first light-emitting layer and the second light-emitting layer contain the same organic compound as the second organic compound (8mpTP-4mDBtPBfpm) in the intermediate layer.

[0551] (Method for manufacturing light emitting device 1-8) Light-emitting device 1-8 is manufactured in the same manner as light-emitting device 1-1 except that hpp2Py (the second organic compound) in light-emitting device 1-1 is replaced with 11-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furano[2,3-b]pyrazine (abbreviated as: 11mDBtBPPnfpr) represented by the above structural formula (VIII).

[0552] The device structures of light-emitting devices 1-1 to 1-8 and the LUMO energy levels of the second organic compound are shown below. Thus, light-emitting devices 1-1 to 1-8 are light-emitting devices that include a metal and a first organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group and a second organic compound having a second π-electron-deficient heteroaromatic ring in the first layer.

[0553] Note that the values ​​of the HOMO energy level and the LUMO energy level were obtained by cyclic voltammetry (CV) measurement.

[0554] In cyclic voltammetry (CV) measurements, the oxidation peak potential (E pa ) and reduction peak potential (E pc ) to calculate the HOMO energy level and the LUMO energy level (E). In the measurement, the HOMO energy level is calculated from the potential scan in the positive direction, and the LUMO energy level is calculated from the potential scan in the negative direction. In addition, the scanning speed in the measurement is 0.1 V / s.

[0555] Specifically, the oxidation peak potential (E pa ) and reduction peak potential (E pc ) to calculate the standard redox potential (E o )(=(E pa +E pc ) / 2), from the potential energy of the reference electrode relative to the vacuum level (E x ) minus the standard redox potential (E o ), from which the HOMO energy level and LUMO energy level values ​​(E) (=E x -E o ).

[0556] Note that the above shows the case where a reversible redox wave is obtained. In the case where an irreversible redox wave is obtained, the oxidation peak potential (E pa ) minus a certain value (0.1 eV) is assumed to be the reduction peak potential (E pc ), calculate the standard redox potential (E o ), and the HOMO energy level is calculated. pc) plus a certain value (0.1 eV) is assumed to be the oxidation peak potential (E pa ), calculate the standard redox potential (E o ), and the LUMO level is calculated from this.

[0557] In addition, the glass transition temperature (Tg) of the second organic compound in the intermediate layer of the light-emitting devices 1-2 to 1-8 was measured by a differential scanning calorimeter (DSC). The Tg of mPPhen2P was 135°C, the Tg of αN-βNPAnth was 128°C, the Tg of ZADN was 169°C, the Tg of mSiTrz was 108°C, the Tg of mPn-mDMePyPTzn was 121°C, the Tg of 8mpTP-4mDBtPBfpm was 120°C, and the Tg of 11mDBtBPPnfpr was 130°C, which shows that they have high heat resistance.

[0558] [Table 5]

[0559] [Table 6]

[0560] Fig. 22 The luminance-current density characteristics of the light emitting devices 1-1 to 1-8 are shown. Fig.23 The brightness-voltage characteristics are shown. Fig.24 The current efficiency-current density characteristics are shown. Fig.25 The current density-voltage characteristics are shown. Fig.26 The electric field emission spectra thereof are shown in Table 7. In addition, Table 7 shows the 1000 cd / m 2 Note that the brightness, CIE chromaticity, and electric field emission spectrum were measured at room temperature using a spectroradiometer (manufactured by Topcon, SR-UL1R).

[0561] [Table 7]

[0562] from Figure 22 to Figure 26 As can be seen from Table 6, the light-emitting devices 1-1 to 1-8 are all series-connected light-emitting devices with good current efficiency.

[0563] In addition, according to Fig. 27 It can be seen from the current density-voltage characteristics of the light-emitting devices 1 - 1 to 1 - 8 that the driving voltages of the light-emitting devices 1 - 1 to 1 - 8 are different.

[0564] Here, Fig.28The current density of the light emitting devices 1-1 to 1-8 is 50 mA / cm 2 As can be seen from the figure, when the LUMO energy level of the second organic compound is below -2.75eV, more obviously below -2.80eV, more obviously below -2.85eV, more obviously below -2.90eV, and further obviously below -2.95eV, the driving voltage is significantly reduced.

[0565] That is, according to this embodiment, when the LUMO energy level of the first organic compound is -2.55eV, in order to reduce the driving voltage of the light-emitting device, the LUMO energy level of the second organic compound is preferably lower than the LUMO energy level of the first organic compound by more than 0.20eV, more preferably lower by more than 0.25eV, more preferably lower by more than 0.30eV, more preferably lower by more than 0.35eV, and more preferably lower by more than 0.40eV. Example 2

[0566] In this embodiment, the detailed manufacturing method and characteristics of the light-emitting devices 2-1 to 2-4 of the tandem light-emitting devices using an organic compound (second organic compound) having electron transport properties with different LUMO energy levels as the first layer of the intermediate layer are described. The structural formulas of the main compounds used in this embodiment are shown below.

[0567] [Chemical formula 9]

[0568] [Chemical formula 10]

[0569] (Method for manufacturing light emitting device 2-1) First, a 100 nm thick silver, palladium, and copper alloy (APC: Ag-Pd-Cu) as a reflective electrode and a 50 nm thick indium tin oxide (ITSO) containing silicon oxide as a transparent electrode were deposited on a glass substrate by sputtering from one side of the substrate to form a first electrode 101 with a size of 2 mm×2 mm. The transparent electrode was used as an anode and was considered as the first electrode 101 in combination with the above-mentioned reflective electrode.

[0570] Next, as a pretreatment for forming a light-emitting device on the substrate, the surface of the substrate was washed with water and baked at 200° C. for 1 hour.

[0571] Then, the substrate is placed inside the chamber and the pressure is reduced to 1×10 -4 Pa in a vacuum evaporation equipment, and vacuum bake at a temperature of 170°C for 30 minutes in a heating chamber in the vacuum evaporation equipment, and then the substrate is cooled for about 30 minutes.

[0572] Next, the substrate is fixed on a bracket provided in a vacuum evaporation device in a manner such that the surface on which the first electrode 101 is formed faces downward, and N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviated as: PCBBiF) represented by the above structural formula (i) and a material having an electron acceptor property and containing fluorine and having a molecular weight of 672 (OCHD-003) are co-evaporated on the first electrode 101 by a method in a weight ratio of 1:0.03 (=PCBBiF:OCHD-003) and a thickness of 10 nm, thereby forming a hole injection layer 111.

[0573] PCBBiF was evaporated on the hole injection layer 111 to a thickness of 125 nm, thereby forming a first hole transport layer.

[0574] Next, on the first hole transport layer, 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as 8mpTP-4mDBtPBfpm) represented by the above structural formula (ii), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as βNCCP) represented by the above structural formula (iii) and [2-d3-methyl-8-(2-pyridin-2-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as 8mpTP-4mDBtPBfpm) represented by the above structural formula (iv) were added. The first light-emitting layer is formed by co-evaporation in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)) and a thickness of 40nm, wherein the first light-emitting layer is prepared by co-evaporation.

[0575] Then, 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) represented by the above structural formula (viii) was evaporated in a thickness of 10 nm to form a first electron transport layer.

[0576] After forming the first electron transport layer, 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as mPPhen2P) represented by the above structural formula (II) as the second organic compound and 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as Pyrrd-Phen) and indium (In) represented by the above structural formula (vi) as the first organic compound were mixed in a weight ratio of 0.5:0.5:0.02 (=hpp2py:...

Claims

1. A light emitting device, comprising: a first light emitting device; as well as a second light emitting device, Wherein, the first light emitting device comprises: a first electrode on an insulating surface; a second electrode opposite to the first electrode; and a first layer between the first electrode and the second electrode, The second light emitting device comprises: a third electrode on the insulating surface; the second electrode facing the third electrode; and a second layer between the third electrode and the second electrode, The second electrode is a conductive layer shared by the first light emitting device and the second light emitting device. The second electrode and the first layer overlap with the first electrode, The second electrode and the second layer overlap with the third electrode, The first layer and the second layer each include a first light-emitting layer, a second light-emitting layer, and an intermediate layer between the first light-emitting layer and the second light-emitting layer, The intermediate layer includes a first region including a first organic compound, a second organic compound, and a metal or a metal oxide, The first organic compound comprises a first π-electron-deficient heteroaromatic ring having an electron-donating group, The second organic compound has a second π-electron-deficient heteroaromatic ring, The LUMO energy level of the second organic compound is smaller than the LUMO energy level of the first organic compound by at least 0.20 eV, Furthermore, a distance between the first layer and the second layer is greater than or equal to 0.5 μm and less than or equal to 5 μm.

2. The light emitting device according to claim 1, When the LUMO energy level of the first organic compound is expressed as LUMO1 (eV), the LUMO energy level LUMO2 (eV) of the second organic compound satisfies LUMO1-0.50≤LUMO2≤LUMO1-0.

20.

3. The light emitting device according to claim 1, The first π-electron-deficient heteroaromatic ring is a heteroaromatic ring containing two or more pyridine rings.

4. The light emitting device according to claim 1, The acidity coefficient pKa of the first organic compound is greater than 8.

5. The light emitting device according to claim 1, The first π-electron-deficient heteroaromatic ring is different from the second π-electron-deficient heteroaromatic ring.

6. The light emitting device according to claim 1, The second organic compound has at least one of an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, a triazole ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring or a triazine ring.

7. The light emitting device according to claim 1, The acidity coefficient pKa of the second organic compound is less than 4.

8. The light emitting device according to claim 1, wherein the first light-emitting layer is closer to the first electrode than the second light-emitting layer, The first light-emitting layer comprises a third organic compound, The third organic compound has a third π-electron-deficient heteroaromatic ring, And the third π-electron-deficient heteroaromatic ring is the same as the second π-electron-deficient heteroaromatic ring.

9. The light emitting device according to claim 1, wherein the first light-emitting layer is located on the first electrode side of the second light-emitting layer, The first light-emitting layer comprises a third organic compound, And the third organic compound is the same as the second organic compound.

10. The light emitting device according to claim 9, further comprising: A first electron transport layer between the first light-emitting layer and the intermediate layer, wherein the first electron transport layer comprises a fourth organic compound, And the fourth organic compound is different from the third organic compound.

11. The light emitting device according to claim 1, The metal belongs to any of Group 3, Group 11, Group 12 and Group 13.

12. The light emitting device according to claim 1, The electron-donating group is any one or more of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group and a heterocyclic amino group.

13. The light emitting device according to claim 1, The threshold value of the electron density distribution in the atomic unit system is 0.0004e / a0 3 When the minimum value of the electrostatic potential of the first organic compound is less than -0.

085.

14. The light emitting device according to claim 1, The first organic compound, the second organic compound, and the metal or the metal oxide are mixed in the first region.

15. The light emitting device according to claim 1, In the first region, a layer including the metal or the metal oxide and a layer in which the first organic compound and the second organic compound are mixed are stacked.

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