Light emitting device

Abstract

Provided is a light emitting device including: a first electrode; a second electrode; and an organic compound layer on the first insulating layer. The organic compound layer is located between the first electrode and the second electrode, the second electrode and the organic compound layer are separated from the second electrode and the organic compound layer of at least one of a plurality of other light-emitting devices adjacent to the light-emitting device, and the outline of the second electrode substantially coincides with the outline of the organic compound layer. The organic compound layer comprises a light-emitting layer and an electron injection layer, the electron injection layer comprises a metal or a metal compound, a first organic compound and a second organic compound, the first organic compound comprises a pi-electron-deficient heteroaromatic ring, and the second organic compound comprises more than two heteroaromatic rings. The more than two heteroaromatic rings comprise more than three heteroatoms in total.

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 aforementioned technical field. Examples of the technical fields of one embodiment of the present invention include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), and methods for driving or manufacturing such devices. Background Art

[0003] In recent years, display devices have been used in a variety of applications. For example, large-scale display devices are being developed for home televisions (also known as televisions or TV receivers), digital signage, and public information displays (PIDs). Small-scale display devices are also being developed for touch-panel smartphones and tablets.

[0004] At the same time, the definition of display devices is also being advanced. Devices requiring high-definition displays, such as those for virtual reality (VR), augmented reality (AR), substitute reality (SR), and mixed reality (MR), are already under development.

[0005] The development of light-emitting devices (also called luminescent elements) as display elements for display devices is rapidly gaining momentum. Light-emitting devices (also called EL devices or EL elements) that utilize the electroluminescence (EL) phenomenon, particularly organic EL devices primarily using organic compounds, have the following advantages: they are easily thinner and lighter, can respond quickly to input signals, and can be driven using a DC constant voltage power supply. Therefore, they are highly suitable for use in display devices.

[0006] To achieve higher-definition light-emitting devices using organic EL devices, research is underway to pattern organic layers using photolithography techniques using photoresists, etc., instead of vapor deposition techniques using metal masks. Using photolithography, high-definition display devices with organic compound layer spacing of several micrometers can be achieved (see, for example, Patent Document 1).

[0007] [Patent Document 1] Japanese PCT International Application Translation No. 2018-521459 Summary of the Invention

[0008] It has been known that the cathode and organic compound layers in organic EL devices are affected by exposure to atmospheric components such as water and oxygen, affecting their initial characteristics and reliability. Consequently, conventional procedures have required processing in an inert gas atmosphere or near-vacuum atmosphere. In particular, electron injection layers using alkali metals or alkaline earth metals or their compounds are highly reactive with water and oxygen. Exposure of the surface of the organic compound layer to the atmosphere rapidly degrades the electron injection layer, rendering it ineffective as an electron injection layer.

[0009] However, during the processing by the above-mentioned photolithography method, the organic EL device needs to be exposed to the atmosphere.

[0010] One object of one embodiment of the present invention is to provide a novel light-emitting device. Another object of one embodiment of the present invention is to provide a light-emitting device with good efficiency. Another object of one embodiment of the present invention is to provide a light-emitting device with good reliability. Another object of one embodiment of the present invention is to provide a light-emitting device with good efficiency.

[0011] Another object of one embodiment of the present invention is to provide a novel light-emitting device manufactured through a photolithography process. Another object of one embodiment of the present invention is to provide a light-emitting device manufactured through a photolithography process and having good efficiency. Another object of one embodiment of the present invention is to provide a light-emitting device manufactured through a photolithography process. Another object of one embodiment of the present invention is to provide a light-emitting device manufactured through a photolithography process and having good luminous efficiency.

[0012] Another object of one embodiment of the present invention is to provide a novel light-emitting device that can be used in a high-definition display device. Another object of one embodiment of the present invention is to provide a light-emitting device that can be used in a high-definition display device and has good efficiency. Another object of one embodiment of the present invention is to provide a light-emitting device that can be used in a high-definition display device. Another object of one embodiment of the present invention is to provide a light-emitting device that can be used in a high-definition display device and has good luminous efficiency.

[0013] Another object of one embodiment of the present invention is to provide a highly reliable display device. Another object of one embodiment of the present invention is to provide a high-definition display device. Another object of one embodiment of the present invention is to provide a high-definition display device.

[0014] Note that the inclusion of these objectives does not preclude the existence of other objectives. One embodiment of the present invention does not necessarily achieve all of the above objectives. Objectives other than the above objectives may be extracted from the description of the specification, drawings, and claims.

[0015] One embodiment of the present invention is a light-emitting device comprising: a first electrode on a first insulating layer; a second electrode on the first insulating layer; and an organic compound layer on the first insulating layer, wherein the first electrode is formed in contact with the first insulating layer, the organic compound layer is located between the first electrode and the second electrode, the second electrode and the organic compound layer are separated from the second electrode and the organic compound layer of at least one of a plurality of other light-emitting devices adjacent to the light-emitting device, and when viewed from a direction substantially perpendicular to a surface of the first insulating layer on which the first electrode is formed, the contour of the second electrode substantially coincides with the contour of the organic compound layer. The organic compound layer comprises a light-emitting layer and an electron injection layer, the electron injection layer comprising a metal or a metal compound, a first organic compound, and a second organic compound, the first organic compound comprising a π-electron-deficient heteroaromatic ring, the second organic compound comprising two or more heteroaromatic rings, the two or more heteroaromatic rings being bonded or fused to each other and comprising a total of three or more heteroatoms, and the second organic compound having a function as a multidentate ligand in which two or more of the three or more heteroatoms interact with the metal or the metal compound.

[0016] In the light-emitting device of one embodiment of the above invention, the organic compound layer includes a P-type layer between the electron injection layer and the second electrode, and the P-type layer includes a third organic compound having a hole-transporting property and a fourth organic compound or metal oxide having at least one of a halogen group and a cyano group.

[0017] In the light-emitting device of one embodiment of the above invention, the second organic compound has a function of interacting with the metal or the metal compound via two or more of the three or more heteroatoms as a bidentate ligand or a tridentate ligand.

[0018] 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, the light-emitting device group including: a first electrode group formed on a common insulating surface; a second electrode group opposing the first electrode group; and a first layer group located between the first electrode group and the second electrode group, the light-emitting device including: a first electrode; a second electrode; and a first layer, wherein the first electrode is one of the first electrode group, the first electrode is independent for each of the plurality of light-emitting devices, the first layer is one of the first layer group, the first layer is independent for each of the plurality of light-emitting devices, the second electrode is one of the second electrode group, the second electrode is independent for each of the plurality of light-emitting devices, the second electrode and the first layer are independent for each of the plurality of light-emitting devices The first electrodes overlap, the first layer includes a light-emitting layer and an electron injection layer, the electron injection layer includes a metal or a metal compound, a first organic compound and a second organic compound, the first organic compound includes a π-electron-deficient heteroaromatic ring, the second organic compound includes two or more heteroaromatic rings, the two or more heteroaromatic rings are bonded to each other or fused and include a total of three or more heteroatoms, the second organic compound is an organic compound having the function of interacting with the metal or metal compound by two or more of the three or more heteroatoms as a multidentate ligand, and the spacing 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.

[0019] In addition, in a light-emitting device of one embodiment of the above invention, the first layer includes a P-type layer between the electron injection layer and the second electrode, and the P-type layer includes a third organic compound having a hole-transporting property and a fourth organic compound or metal oxide having at least one of a halogen group and a cyano group.

[0020] In the light-emitting device of one embodiment of the above invention, the second organic compound has a function of interacting with the metal or the metal compound via two or more of the three or more heteroatoms as a bidentate ligand or a tridentate ligand.

[0021] Furthermore, in the light-emitting device according to one embodiment of the present invention, the contour of the second electrode substantially coincides with the contour of the first layer when viewed in a direction substantially perpendicular to the insulating surface.

[0022] Furthermore, in the light emitting device of one embodiment of the above invention, an end portion of a cross section of the second electrode and an end portion of a cross section of the first layer are aligned in a direction substantially perpendicular to the insulating surface.

[0023] One embodiment of the present invention is a light-emitting device, comprising: a first electrode on a first insulating layer; a second electrode on the first insulating layer; and an organic compound layer on the first insulating layer, wherein the first electrode is formed in contact with the first insulating layer, the organic compound layer is located between the first electrode and the second electrode, the second electrode and the organic compound layer are separated from the second electrode and the organic compound layer of at least one of a plurality of other light-emitting devices adjacent to the light-emitting device, when viewed from a direction approximately perpendicular to the surface of the first insulating layer on which the first electrode is formed, the contour of the second electrode is approximately consistent with the contour of the organic compound layer, the organic compound layer includes a light-emitting layer and an electron injection layer, the electron injection layer includes a metal or a metal compound, a first organic compound and a second organic compound, the first organic compound includes a π-electron-deficient heteroaromatic ring, and the second organic compound is represented by the general formula (G1-1).

[0024] [Chemical Formula 1]

[0025] In the general formula (G1-1), A 1 、A 2 and A 3 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 、A 2 and A 3 Condensed rings can also be formed.

[0026] In addition, in a light-emitting device of one embodiment of the above invention, the organic compound layer includes a P-type layer between the electron injection layer and the second electrode, and the P-type layer includes a third organic compound having a hole-transporting property and a fourth organic compound or metal oxide having at least one of a halogen group and a cyano group.

[0027] One embodiment of the present invention is a light-emitting device, comprising: a first electrode on a first insulating layer; a second electrode on the first insulating layer; and an organic compound layer on the first insulating layer, wherein the first electrode is formed in contact with the first insulating layer, the organic compound layer is located between the first electrode and the second electrode, the second electrode and the organic compound layer are separated from the second electrode and the organic compound layer of at least one of a plurality of other light-emitting devices adjacent to the light-emitting device, when viewed from a direction approximately perpendicular to the surface of the first insulating layer on which the first electrode is formed, the contour of the second electrode is approximately consistent with the contour of the organic compound layer, the organic compound layer includes a light-emitting layer and an electron injection layer, the electron injection layer includes a metal or a metal compound, a first organic compound and a second organic compound, the first organic compound includes a π-electron-deficient heteroaromatic ring, and the second organic compound is represented by the general formula (G1-2).

[0028] [Chemical Formula 2]

[0029] In the general formula (G1-2), A 1 and A 2 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 and A 2 It can also form a fused ring, A 1 Contains two or more nitrogen atoms.

[0030] In addition, in a light-emitting device of one embodiment of the above invention, the organic compound layer includes a P-type layer between the electron injection layer and the second electrode, and the P-type layer includes a third organic compound having a hole-transporting property and a fourth organic compound or metal oxide having at least one of a halogen group and a cyano group.

[0031] In addition, in the light-emitting device according to one embodiment of the above invention, the heteroaromatic ring is a π-electron-deficient heteroaromatic ring.

[0032] In the light-emitting device of one embodiment of the above invention, the heteroaromatic ring includes at least one of a pyridine ring, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring), a triazine ring, an azole ring (imidazole ring, pyrazole ring, oxazole ring, thiazole ring), and a triazole ring.

[0033] In the light-emitting device according to one embodiment of the above invention, at least one of the heteroaromatic rings included in the second organic compound includes a diazine ring (a pyrazine ring, a pyrimidine ring, or a pyridazine ring) or a triazine ring. In the light-emitting device according to one embodiment of the above invention, the heteroaromatic rings included in the second organic compound include a total of three or more pyridine rings.

[0034] In the light-emitting device according to one embodiment of the above invention, the first organic compound has an electron-donating group, and the electron-donating group is at least one of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group.

[0035] In the light-emitting device of one embodiment of the above invention, the acidity coefficient pK of the first organic compound is a is greater than or equal to 8. In addition, the first organic compound includes a phenanthroline ring.

[0036] In the light-emitting device of one embodiment of the above invention, the glass transition temperature of the second organic compound is T g The temperature is not less than 100° C. In addition, the lowest unoccupied molecular orbital (LUMO) energy level of the second organic compound is lower than the LUMO energy level of the first organic compound.

[0037] In the light-emitting device according to one embodiment of the above invention, the metal belongs to Group 1, Group 3, Group 11, or Group 13 of the periodic table.

[0038] In the light-emitting device according to one embodiment of the present invention, the electron injection layer is a mixture of a metal, a second organic compound, and a first organic compound. Furthermore, the electron injection layer is a stack of a layer containing a metal and a layer containing the second organic compound or the first organic compound.

[0039] In addition, one embodiment of the present invention is a light-emitting device comprising a plurality of light-emitting devices, wherein the plurality of light-emitting devices are any of the above-mentioned light-emitting devices, and the plurality of light-emitting devices each include an organic compound layer, the organic compound layer including a light-emitting layer and an electron injection layer located between a first electrode and a second electrode, and the second electrode and the organic compound layer included in each of the plurality of light-emitting devices are independent of each other.

[0040] Another embodiment of the present invention is a display module including the above-mentioned light-emitting device and at least one of a connector and an integrated circuit.

[0041] Another embodiment of the present invention is an electronic device including the light-emitting device described above and at least one of a housing, a battery, a camera, a speaker, and a microphone.

[0042] According to one embodiment of the present invention, a novel light-emitting device can be provided. Furthermore, according to one embodiment of the present invention, a light-emitting device with good efficiency can be provided. Furthermore, according to one embodiment of the present invention, a light-emitting device with good reliability can be provided. Furthermore, according to one embodiment of the present invention, a light-emitting device with good efficiency and reliability can be provided.

[0043] Furthermore, one embodiment of the present invention can provide a novel light-emitting device manufactured through a photolithography process. Furthermore, one embodiment of the present invention can provide a light-emitting device manufactured through a photolithography process with excellent efficiency. Furthermore, one embodiment of the present invention can provide a light-emitting device manufactured through a photolithography process with excellent reliability. Furthermore, one embodiment of the present invention can provide a light-emitting device manufactured through a photolithography process with excellent luminous efficiency and reliability.

[0044] Furthermore, according to one embodiment of the present invention, a novel light-emitting device that can be used in a high-definition display device can be provided. Furthermore, according to one embodiment of the present invention, a light-emitting device with good efficiency that can be used in a high-definition display device can be provided. Furthermore, according to one embodiment of the present invention, a light-emitting device with good reliability that can be used in a high-definition display device can be provided. Furthermore, according to one embodiment of the present invention, a light-emitting device with good luminous efficiency and reliability that can be used in a high-definition display device can be provided.

[0045] Furthermore, one embodiment of the present invention can provide a highly reliable display device. Furthermore, one embodiment of the present invention can provide a high-definition display device. Furthermore, one embodiment of the present invention can provide a high-definition and highly reliable display device.

[0046] Furthermore, one embodiment of the present invention can provide a novel organic compound, a novel light-emitting device, a novel display device, a novel display module, and a novel electronic device.

[0047] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of 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

[0048] Figures 1A to 1C is a diagram showing a light emitting device; Figure 2 is the analysis result of the spin density distribution in the ground state of the composite material; Figure 3 is the analysis result of the electrostatic potential diagram of the composite material in the ground state; Figure 4A and Figure 4B is a diagram showing a light emitting device; Figure 5A and Figure 5B is a top view and a cross-sectional view of the light emitting device; Figures 6A to 6E is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figure 7A and Figure 7B is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figures 8A to 8D is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figures 9A to 9C is a cross-sectional view illustrating an example of a method for manufacturing a display device; 10A to 10C is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figure 11A and Figure 11Bis a cross-sectional view illustrating an example of a method for manufacturing a display device; Figure 12A and Figure 12B is a perspective view showing a structural example of a display module; Figure 13A and Figure 13B is a cross-sectional view showing a structural example of a display device; Figure 14 is a perspective view showing a structural example of a display device; Figure 15 is a cross-sectional view showing a structural example of a display device; Figure 16 is a cross-sectional view showing a structural example of a display device; Figure 17A is a cross-sectional view showing a structural example of a display device, Figure 17B and Figure 17C is a top view showing a structural example of a display device; Figure 18 is a cross-sectional view showing a structural example of a display device; Figure 19A is a cross-sectional view showing a structural example of a display device, Figure 19B and Figure 19C is a top view showing a structural example of a display device; 20A to 20D is a diagram showing an example of an electronic device; Figures 21A to 21F is a diagram showing an example of an electronic device; Figures 22A to 22G is a diagram showing an example of an electronic device; Figures 23A to 23G is a diagram showing an example of a pixel layout; Figure 24 is a diagram illustrating the structure of a light emitting device; Figure 25 is a graph illustrating brightness-current density characteristics of a light-emitting device; Figure 26 is a graph illustrating brightness-voltage characteristics of a light-emitting device; Figure 27 is a graph illustrating current efficiency-current density characteristics of a light-emitting device; Figure 28 is a graph illustrating current density-voltage characteristics of a light emitting device; Figure 29 is a diagram illustrating the electroluminescence spectrum of a light-emitting device. DETAILED DESCRIPTION

[0049] 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 those skilled in the art will readily appreciate that the embodiments and details can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited solely to the embodiments described below.

[0050] Note that in this specification and other documents, devices manufactured using a metal mask or FMM (Fine Metal Mask) are sometimes referred to as devices with an MM (Metal Mask) structure. Furthermore, in this specification and other documents, devices manufactured without using a metal mask or FMM are sometimes referred to as devices with an MML (Metal Mask Less) structure.

[0051] Implementation Method 1 As one of the methods for forming an organic semiconductor film into a predetermined shape, vacuum evaporation using a metal mask (mask evaporation) is widely used. However, with the recent progress in high density and high definition, further high definition by mask evaporation is approaching its limit due to various reasons, such as problems with position alignment accuracy and problems with the configuration spacing with the substrate. On the other hand, it is expected that organic semiconductor devices with denser patterns can be realized by processing the shape of the organic semiconductor film using photolithography. Furthermore, photolithography is easier to achieve large areas than mask evaporation, so research on organic semiconductor film processing using photolithography is underway.

[0052] Furthermore, it has been known that the organic compound layer and cathode in an organic EL device are affected in initial characteristics and reliability when exposed to atmospheric components such as water and oxygen, and therefore are processed in an inert gas atmosphere or a near-vacuum atmosphere in conventional procedures.

[0053] In particular, alkali metals, alkaline earth metals or their compounds (hereinafter also referred to as Li compounds, etc.) are sometimes used for the electron injection layer of the light-emitting device. However, these Li compounds, etc. are highly reactive with water or oxygen, and deteriorate instantaneously as long as they are exposed to the atmosphere, and the electron injectivity is greatly reduced. In addition, when other metals with small work functions are used for the cathode, when exposed to water, oxygen, etc., the electron injectivity may be reduced and the driving voltage may be greatly increased.

[0054] However, the photolithography process requires that the light-emitting device being manufactured be exposed to the atmosphere. Furthermore, the photolithography process uses various chemical solutions and also involves a cleaning step, creating harsh conditions that further accelerate degradation.

[0055] Therefore, when the cathode and organic compound layer are processed by photolithography, the electron injectivity of the cathode and electron injection layer is significantly reduced. As a result, the driving voltage of the organic EL device processed by photolithography increases significantly, making it difficult to obtain good characteristics.

[0056] To avoid this characteristic degradation, there is also a method that forms the electron injection layer and cathode after photolithography. However, performing the processing after forming the two electrodes minimizes the increase in photolithography steps and offers significant cost advantages. Furthermore, the organic compound layer's exposure to chemical solutions and the atmosphere is significantly reduced, achieving performance comparable to light-emitting devices manufactured without exposure to the atmosphere.

[0057] Therefore, one embodiment of the present invention provides a light-emitting device including a first electrode, an organic compound layer, and a second electrode from the substrate side. The light-emitting device is manufactured by a photolithography process after forming the second electrode and has excellent characteristics.

[0058] Specifically, Figure 1A A schematic diagram of a light-emitting device according to one embodiment of the present invention is shown. The first electrode 101 of the light-emitting device is provided on an insulator 1000, and an organic compound layer 103 (also referred to as an EL layer) is provided between the first electrode 101 and the second electrode 102. The organic compound layer 103 includes at least a light-emitting layer 113 and an electron-injection layer 115. The light-emitting layer 113 contains a light-emitting substance and emits light when a voltage is applied between the first electrode 101 and the second electrode 102.

[0059] Preferably, if Figure 1A As shown, in addition to the light-emitting layer 113 and the electron-injection layer 115, the organic compound layer 103 includes functional layers such as a hole-injection layer 111, a hole-transport layer 112, an electron-transport layer 114, and an electron-injection layer 115. Note that the organic compound layer 103 may include functional layers other than the aforementioned functional layers, such as the hole-blocking layer, the electron-blocking layer, the exciton-blocking layer, and the intermediate layer. Conversely, any of the aforementioned layers may not be provided.

[0060] As mentioned above, the high reactivity of alkali metal compounds used in the electron injection layer is one of the reasons for their degradation due to their sensitive reactions during exposure to the atmosphere, etching, washing, etc. Therefore, it is believed that if less reactive substances can be used instead of alkali metal compounds, the increase in driving voltage can be suppressed even when processing is performed using photolithography.

[0061] Compared to alkali metal compounds, most metal oxides (excluding alkali metal oxides) among metal compounds are relatively stable and therefore easy to handle. In addition, because metal oxides are relatively stable, they deteriorate less even when exposed to the atmosphere. However, due to their stability, even if metal oxides are used in existing light-emitting devices instead of alkali metal compounds in the electron injection layer, it is difficult to obtain the same properties as alkali metal compounds, and therefore it is impossible to obtain organic EL devices with properties that can withstand actual use.

[0062] Therefore, in one embodiment of the present invention, by using a metal or a metal compound, a first organic compound including a π-electron-deficient heteroaromatic ring, and a second organic compound including two or more heteroaromatic rings that are bonded to or fused with each other and include a total of three or more heteroatoms as the electron injection layer 115, an organic EL device with good characteristics can be obtained even after a photolithography process accompanied by atmospheric exposure of the organic compound layer.

[0063] By adopting this structure, the first organic compound acts as an electron donor (electron donor) relative to the second organic compound, and the first organic compound, metal, and second organic compound interact to form a donor energy level (singly occupied molecular orbital (SOMO) energy level or highest occupied molecular orbital (HOMO) energy level). When the first organic compound, metal, and second organic compound interact, the donor energy level (SOMO energy level or HOMO energy level) is high, thereby lowering the electron injection barrier from the electron injection layer to the electron transport layer. This interaction allows electrons to be smoothly injected and transported from the electron injection layer 115 to the electron transport layer 114, thereby manufacturing a light-emitting device with a low driving voltage.

[0064] Note that the LUMO and HOMO levels of organic compounds 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.

[0065] Furthermore, the SOMO level originates from the orbital of unpaired electrons contained in the metal. When the metal, the first organic compound, and the second organic compound interact, the SOMO level can also be distributed in the orbitals of the first and second organic compounds. In other words, the electron orbitals of the metal and the organic compound interact.

[0066] Note that an organic compound comprising a plurality of atoms capable of interacting with each other can interact more stably with a metal. Therefore, as a second organic compound used in one embodiment of the present invention, a material that interacts with a metal as a bidentate or tridentate or higher multidentate ligand is preferably used. Since an organic compound that interacts with a metal as a multidentate ligand becomes stable when interacting with the metal, an electron injection layer that is resistant to oxygen and water in the atmosphere and to water and liquid used for a process in photolithography can be formed.

[0067] As the atoms that interact, heteroatoms with non-shared electron pairs in organic compounds can be cited. For example, oxygen (O), nitrogen (N), sulfur (S), phosphorus (P) can be cited, wherein nitrogen is preferably. Nitrogen has a high electronegativity and is therefore easy to interact with metals. In addition, since nitrogen can form conjugated bonds in organic compounds, organic compounds with high carrier transport properties can be achieved by using nitrogen in molecules, especially in heteroaromatic rings. Note that the heteroaromatic ring is more preferably an even-numbered ring such as a six-membered ring or an eight-membered ring. By adopting this structure, the non-shared electron pair on nitrogen does not involve conjugation and is therefore easy to interact with metals.

[0068] The metal or metal compound, the first organic compound and the second organic compound form a donor energy level (SOMO energy level or HOMO energy level) by interacting with each other, which can reduce the electron injection barrier to the electron transport layer, and can smoothly inject and transport electrons from the electron injection layer to the electron transport layer. The heteroaromatic ring included in the second organic compound is preferably a π-electron-deficient heteroaromatic ring. By adopting this structure, the second organic compound can have electron transport properties, and can smoothly inject and transport electrons from the electron injection layer to the electron transport layer. In addition, the second organic compound includes two or more heteroaromatic rings, which are bonded to each other or fused and include a total of three or more nitrogen atoms, thereby making the LUMO energy level of the second organic compound lower than the LUMO energy level of the first organic compound. By using a material having a LUMO energy level lower than that of the first organic compound as the second organic compound, stabilization of the intermediate layer can be achieved when the metal or metal compound, the first organic compound and the second organic compound interact.

[0069] The second organic compound preferably includes a π-deficient heteroaromatic ring with an unshared electron pair. By adopting this structure, it is possible to stably interact with a metal or a metal compound. The second organic compound preferably includes two or more π-deficient heteroaromatic rings with an unshared electron pair and a material that interacts with a metal as a bidentate or higher polydentate ligand. Because the organic compound that interacts with the metal as a bidentate or higher polydentate ligand becomes stable when interacting with the metal.

[0070] Furthermore, the first organic compound preferably has an electron-donating substituent. This structure allows the first organic compound to have both a high HOMO energy level and a high LUMO energy level, thereby increasing the difference between the LUMO energy levels of the first organic compound and the second organic compound. Consequently, the interaction between the metal or metal compound, the first organic compound, and the second organic compound further stabilizes the intermediate layer.

[0071] As described above, since the interaction between the first and second organic compounds stabilizes the structure, electrons can be smoothly injected and transported from the electron injection layer to the adjacent electron transport layer, even during a photolithography process involving exposure of the EL layer to the atmosphere. Consequently, photolithography can be used to manufacture light-emitting devices that suppress increases in driving voltage, achieve excellent luminous efficiency, and exhibit high reliability.

[0072] In addition, metals with small work functions, represented by alkali metals and alkaline earth metals, and their compounds are highly reactive with oxygen or water. Therefore, when they are used in light-emitting devices processed using photolithography, they lead to a decrease in luminous efficiency, an increase in driving voltage, a decrease in driving life, and the generation of shrinkage (non-luminous area at the end of the light-emitting part), which sometimes leads to a decrease in the characteristics of the light-emitting device or a decrease in reliability.

[0073] On the other hand, in one embodiment of the present invention, even if an alkali metal or alkaline earth metal or a compound thereof is used, stabilization is achieved by interaction with a first organic compound including a π-electron-deficient heteroaromatic ring and a second organic compound including two or more heteroaromatic rings, which are bonded to or fused with each other and include a total of three or more heteroatoms. Therefore, an electron injection layer resistant to oxygen and water in the atmosphere and water and chemical solutions used in the process of photolithography can be formed.

[0074] When alkali metals and alkaline earth metals and their compounds are used as metals in one embodiment of the present invention, the donor energy level (SOMO energy level or HOMO energy level) formed by the interaction of a first organic compound including a π-electron-deficient heteroaromatic ring and a second organic compound including two or more heteroaromatic rings, which are bonded to or fused to each other and include a total of three or more heteroatoms, can be high energy. Therefore, the electron injection barrier from the electron injection layer to the electron transport layer can be reduced to smoothly inject and transport electrons from the electron injection layer to the electron transport layer, so it is preferred.

[0075] Furthermore, transition metals (metal elements belonging to Groups 3 to 11) and metal elements belonging to Groups 12 to 14 among typical metals have low reactivity with oxygen and water in the atmosphere, as well as water and chemical solutions used in the photolithography process. Therefore, when using them in light-emitting devices, the degradation caused by water and oxygen, which can occur when using metals with low work functions, is reduced. On the other hand, these metals are stable and have low electron injection properties, which can cause a decrease in the luminous efficiency of light-emitting devices, an increase in driving voltage, and a shortened driving life.

[0076] In the electron injection layer of one embodiment of the present invention, even if a transition metal (a metal element belonging to Group 3 to Group 11) or a metal element belonging to Group 12 to Group 14 in a typical metal is used, a donor energy level (SOMO energy level or HOMO energy level) is formed by interacting with a first organic compound including a π-electron-deficient heteroaromatic ring and a second organic compound including two or more heteroaromatic rings bonded to or fused to each other and including a total of three or more heteroatoms. That is, the electron injection barrier from the electron injection layer to the electron transport layer can be reduced, and electrons can be smoothly injected and transported from the electron injection layer to the electron transport layer. In addition, the structure can be resistant to oxygen and water in the atmosphere and to water and liquid medicine used for the process in the photolithography method. Therefore, one embodiment of the present invention can provide a light-emitting device with good moisture resistance, good water resistance, good oxygen resistance, good chemical resistance, low driving voltage and good luminous efficiency.

[0077] <Analysis of Interactions between Metals and Organic Compounds Using Quantum Chemical Calculations> Here, the interaction between the metal, the first organic compound having an electron-donating property and an unshared electron pair, and the second organic compound having an electron-transporting property was analyzed using quantum chemical calculations.

[0078] [Estimation of the interaction between metals and organic compounds] Here, quantum chemical calculations are used to analyze the spin density and electrostatic potential (ESP) when a metal, a first organic compound including a π-electron-deficient heteroaromatic ring, and a second organic compound including two or more heteroaromatic rings that are bonded or fused to each other and contain a total of three or more heteroatoms. Note that in the calculations, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as Pyrrd-Phen) was used as the first organic compound, and 2,2'- (2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as: 6,6' (P-Bqn)2BPy), with lithium (Li) used as the metal.

[0079] Gaussian09 is used as a quantum chemical calculation program. SGI8600 manufactured by HPE is used for calculation. Density functional theory (DFT) is used to calculate the most stable structures of the first organic compound monomer and the second organic compound monomer in the ground state, 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) is used as the basis function, and B3LYP is used as the 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 by the functional (meaning a function of a function) of the single-electron potential expressed in electron density, the calculation accuracy is high.

[0080] Figure 2 The first organic compound (Pyrrd-Phen), the second organic compound (6,6' The analysis results of the spin density distribution in the ground state of the composite material of (P-Bqn)2BPy) and metal (Li). The balls in the figure represent the atoms that make up the compound, and the clouds around the atoms represent the density value of 0.0004e / a in atomic units. 3 (e represents elementary charge (1e=1.60218×10 -19 C), a0 represents the Bohr radius (1a0=5.29177×10 -11 Note that since the ground states of the first organic compound (Pyrrd-Phen) and the second organic compound (6,6'(P-Bqn)2BPy) are singlet ground states, no spin density distribution is observed.

[0081] In one embodiment of the present invention, when a composite material of a first organic compound (Pyrrd-Phen), a second organic compound (6,6'(P-Bqn)2BPy), and a metal (Li) is in a doublet ground state, the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal (Li) interact with each other, and the metal (Li) coordinates to the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) having non-shared electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atoms at positions 1 and 10 having non-shared electron pairs in the pyridine ring and the benzo[h]quinazoline ring of the second organic compound (6,6'(P-Bqn)2BPy), thereby stabilizing the composite material. Thus, according to Figure 2It can be seen that the spins originating from the unpaired electrons contained in the metal (Li) are locally distributed on the second organic compound (6,6'(P-Bqn)2BPy). Furthermore, no spin density distribution of the metal (Li) is observed. This indicates that the second organic compound (6,6'(P-Bqn)2BPy) is in a radical anion state due to the interaction between the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal (Li).

[0082] then, Figure 3 The results of analyzing the electrostatic potential map in the ground state of a composite material composed of a first organic compound (Pyrrd-Phen), a second organic compound (6,6'(P-Bqn)2BPy), and a metal (Li) are shown. The balls in the figure represent the atoms that make up the compound, and the clouds around the atoms represent a density of 0.0004e / a in atomic units. 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. The electrostatic potential map refers to the electrostatic potential in the equal electron density surface represented by color, where red and blue 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 Figure 3 Since it is a grayscale image, in order to indicate the area with negative electrostatic potential and the area with positive electrostatic potential, the dark red part (i.e., the area with negative electrostatic potential) is surrounded by a dotted line, and the dark blue part (i.e., the area with positive electrostatic potential) is surrounded by a dotted line.

[0083] In one embodiment of the present invention, when a composite material of a first organic compound (Pyrrd-Phen), a second organic compound (6,6'(P-Bqn)2BPy), and a metal (Li) is in a doublet ground state, the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal (Li) interact with each other, and the metal (Li) coordinates to the nitrogen atoms having non-shared electron pairs (nitrogen atoms (N) at positions 1 and 10) in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atoms having non-shared electron pairs in the pyridine ring and benzo[h]quinazoline ring of the second organic compound (6,6'(P-Bqn)2BPy), thereby stabilizing the composite material. As a result, as shown in FIG. Figure 3 As shown, it can be seen that the positive electrostatic potential is mainly distributed on the metal (Li) and the first organic compound (Pyrrd-Phen), and the negative electrostatic potential is mainly distributed on the second organic compound (6,6'(P-Bqn)2BPy). In addition, it can be seen that the second organic compound (6,6' The electrostatic potential around the nitrogen atoms with unshared electron pairs in the pyridine and benzo[h]quinazoline rings of (P-Bqn)2BPy) is negative, while the electrostatic potential around the metal (Li) is positive. Furthermore, the Mulliken partial charge of the Li atom is +0.691e in atomic units.

[0084] [Estimation of SOMO energy level or stability energy] Next, quantum chemical calculations are used to estimate the stability energy and the SOMO energy level formed when a metal, a first organic compound including a π-electron-deficient heteroaromatic ring, and a second organic compound including two or more heteroaromatic rings that are bonded or fused to each other and include a total of three or more heteroatoms interact with each other.

[0085] As a quantum chemical calculation program, Gaussian09 was used. The calculation was performed using SGI8600 manufactured by HPE. First, the most stable structures of the first organic compound, the second organic compound and the metal in their respective ground states, 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 their respective ground states were calculated using density functional theory (DFT). 6-311G (d, p) and LanL2DZ were used as basis functions, and B3LYP was used as a functional function. Next, the stability energy was calculated based on the difference between the total energy of the composite material of the organic compound and the metal and the sum of the total energy of the organic compound monomer and the total energy of the metal monomer. In other words, (stability 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) holds true.

[0086] The calculation results for the following composite material are shown below: lithium (Li) is used as the metal, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as: Pyrrd-Phen) is used as the first organic compound, and 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as: 6,6'(P-Bqn)2BPy) is used as the second organic compound. For comparison, calculation results are also shown for the following composite materials: a composite material using lithium (Li) as the metal, Pyrrd-Phen as the first organic compound, and 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (NBPhen) as the second organic compound instead of 6,6'(P-Bqn)2BPy; a composite material using lithium (Li) and Pyrrd-Phen; a composite material using lithium (Li) and 6,6'(P-Bqn)2BPy; and a composite material using lithium (Li) and NBPhen. Note that 6,6'(P-Bqn)2BPy is a second organic compound containing two or more heteroaromatic rings that are bonded or fused together and contain a total of three or more heteroatoms. On the other hand, NBPhen is an organic compound containing two or more heteroaromatic rings that are bonded or fused together but have a total heteroatom count of less than three.

[0087] [Table 1] Stability energy (eV) SOMO(eV) <![CDATA[Pyrrd-Phen+6,6'(P-Bqn)2BPy+Li]]> -3.79 -2.32 Pyrrd-Phen+NBPhen+Li -3.67 -2.35 Pyrrd-Phen+Li -2.17 -2.46 <![CDATA[6,6'(P-Bqn)2BPy+Li]]> -3.07 -2.88 NBPhen+Li -2.31 -2.96

[0088] [Table 2] LUMO(eV) HOMO(eV) Pyrrd-Phen -1.35 -5.65 <![CDATA[6,6'(P-Bqn)2BPy]]> -2.07 -5.99 tPy2P -1.65 -6.37 2Py3Tzn -2.20 -6.89 NBPhen -2.04 -5.74

[0089] As can be seen from the above table, the negative absolute value of the stability energy of the composite material of lithium (Li), the first organic compound (Pyrrd-Phen) and the second organic compound (6,6'(P-Bqn)2BPy) of one embodiment of the present invention is large. This means that: compared with the case where the organic compound and the metal or metal oxide do not interact, the energy is more stable when the organic compound and the metal or metal oxide interact. 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 (6,6'(P-Bqn)2BPy), the difference with each LUMO energy level is small and the electron injection property is excellent, so it is preferred. Note that the energy levels of the SOMO energy level, HOMO energy level, and LUMO energy level in the table are values obtained by calculation, and sometimes their absolute values are different from those actually measured.

[0090] On the other hand, although not as good as the above-mentioned composite material of lithium (Li), the first organic compound (Pyrrd-Phen) and the second organic compound (6,6'(P-Bqn)2BPy), the stabilization energy of the composite material of lithium (Li), the first organic compound (Pyrrd-Phen) and NBPhen is also negative, and the energy is more stable when the organic compound and the metal interact compared to the case where the organic compound and the metal do not interact.

[0091] Furthermore, the stabilization energy of the composite material of lithium (Li) and the first organic compound (Pyrrd-Phen) is a negative value, and the composite material obtained by adding the second organic compound to the composite material is more stable.

[0092] Furthermore, according to Table 1, the composite material of lithium (Li) and the second organic compound (6,6'(P-Bqn)2BPy) has a relatively low SOMO energy level of -2.88 eV. Meanwhile, the composite material containing the first organic compound (Pyrrd-Phen) in addition to lithium (Li) and the second organic compound (6,6'(P-Bqn)2BPy) has a relatively high SOMO energy level of -2.32 eV, resulting in excellent electron injection properties. Furthermore, while the composite material of lithium (Li) and the second organic compound (6,6'(P-Bqn)2BPy) has a stability energy of -3.07 eV, the composite material containing the first organic compound (Pyrrd-Phen) in addition to lithium (Li) and the second organic compound (6,6'(P-Bqn)2BPy) has a more stable stability energy of -3.79 eV.

[0093] In addition, according to Table 1, the SOMO energy level of the composite material of lithium (Li) and NBPhen is low, that is, -2.96eV. On the other hand, the SOMO energy level of the composite material containing the first organic compound (Pyrrd-Phen) in addition to lithium (Li) and NBPhen is high, that is, -2.35eV, and therefore has excellent electron injection properties. In addition, the stability energy of the composite material of lithium (Li) and NBPhen is -2.31eV, but the stability energy of the composite material containing the first organic compound in addition to lithium (Li) and NBPhen is -2.31eV. The stability energy of the (Pyrrd-Phen) composite material is even more stable, namely -3.67 eV.

[0094] That is, one embodiment of the present invention uses a composite material comprising a metal, a first organic compound including a π-electron-deficient heteroaromatic ring, and a second organic compound, which is stable and has excellent electron injection properties and is suitable for use in an electron injection layer. The second organic compound includes two or more heteroaromatic rings, and the two or more heteroaromatic rings are bonded to or fused with each other and include a total of three or more heteroatoms.

[0095] Next, the following table shows the calculation results of the following composite material: as the metal, a metal belonging to Group 11 or Group 13, specifically silver (Ag) or indium (In) is used; as the first organic compound, Pyrrd-Phen is used; and as the second organic compound, 4',4""-(1,4-phenylene)bis(2,2':6',2"-terpyridine) (abbreviated as: tPy2P) or 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviated as: 2Py3Tzn) is used. In addition, as a comparison, the calculation results of the following composite material are also shown. Results: Silver (Ag) or indium (In) was used as the metal, Pyrrd-Phen was used as the first organic compound, and NBPhen was used instead of the second organic compound. Note that tPy2P and 2Py3Tzn are second organic compounds containing two or more heteroaromatic rings, which are bonded or fused together and contain a total of three or more heteroatoms. On the other hand, NBPhen is an organic compound containing two or more heteroaromatic rings, which are bonded or fused together, but have a total of less than three heteroatoms.

[0096] [Table 3] Stability energy (eV) SOMO(eV) Pyrrd-Phen+tPy2P+In -2.15 -3.03 Pyrrd-Phen+NBPhen+In -1.25 -3.02

[0097] [Table 4] Stability energy (eV) SOMO(eV) Pyrrd-Phen+2Py3Tzn+Ag -1.79 -2.56 Pyrrd-Phen+NBPhen+Ag -1.26 -2.50

[0098] As shown in the table above, the composite material of a metal belonging to Group 11 or Group 13, a first organic compound, and a second organic compound according to one embodiment of the present invention is preferred because of its high stabilization energy and stable structure. Furthermore, the SOMO level formed in this manner is high and has excellent electron injection properties, making it also preferred.

[0099] Note that, considering the manufacturing process of the light-emitting device, in general, in many cases, the EL layer of the light-emitting device, especially the electron injection layer, is deposited by vacuum evaporation. As the material used at this time, it is preferred to use a material that can be easily vacuum-deposited, that is, a material with a low melting point. Because the melting point of metals belonging to Group 11 and Group 13 elements is low, they are suitable for vacuum evaporation. In addition, metals belonging to Group 11 and Group 13 elements are stable to oxygen and water in the atmosphere, so they are preferred. In addition, by using vacuum evaporation, metal atoms and organic compounds can be easily mixed, so it is preferred.

[0100] Ag and In can also be used as cathode materials. Using the same material for both the electron injection layer and the cathode is preferred because it simplifies the manufacture of light-emitting devices and reduces the manufacturing cost of light-emitting devices.

[0101] This indicates that when a first organic compound comprising a π-electron-deficient heteroaromatic ring, a metal, and a second organic compound comprising two or more heteroaromatic rings bonded or fused to each other and containing a total of three or more heteroatoms interact, the first organic compound and the metal act as electron donors for the second organic compound. In one embodiment of the present invention, by using this combination of materials in an electron injection layer, an electron injection layer can be formed that exhibits excellent electron injection properties and is resistant to atmospheric oxygen and water, as well as water and chemical solutions used in photolithography processes. This results in a light-emitting device with reduced driving voltage and high luminous efficiency.

[0102] <<Electron Injection Layer>> like Figure 1A As shown, the electron injection layer 115 is arranged between the second electrode 102 serving as a cathode and the light-emitting layer 113, and includes a metal or a metal compound, a first organic compound including a π-electron-deficient heteroaromatic ring, and a second organic compound including two or more heteroaromatic rings that are bonded to or fused with each other and include a total of three or more heteroatoms.

[0103] <Metal or Metal Compound> As the metal or metal compound, a typical metal or transition metal or a compound thereof can be used. Examples of the metal compound include metal oxides, metal nitrides, metal oxynitrides formed by adding nitrogen to metal oxides, and metal oxynitrides formed by adding oxygen to metal nitrides.

[0104] As typical metals, alkali metals such as Li, Na, K, and Cs (Group 1 elements), alkaline earth metals such as Mg, Ca, and Ba (Group 2 elements), Group 12 elements such as Zn, earth metals such as Al and In (Group 13 elements), Group 14 elements such as Sn, or compounds thereof can be used.

[0105] When alkali metals or alkaline earth metals or their compounds are used as metals, the donor energy level formed by the interaction between the first organic compound and the second organic compound can be a high energy level, thereby allowing electrons to be smoothly injected and transported from the electron injection layer to the electron transport layer, and providing a light-emitting device with a low driving voltage and high light efficiency, so it is preferred.

[0106] As transition metals, Group 3 elements including Y and lanthanide elements such as Eu and Yb, Group 7 elements such as Mn, Group 8 elements such as Fe, Group 9 elements such as Co, Group 10 elements such as Ni and Pt, Group 11 elements such as Cu, Ag, and Au, or compounds thereof can be used. Transition metals are preferred because of their low reactivity with atmospheric components such as water and oxygen.

[0107] Among the above-mentioned metals, it is more preferable to use a metal belonging to an odd-numbered group (Group 1, Group 3, Group 5, Group 7, Group 9, Group 11, or Group 13). Among these odd-numbered group transition metals, metals having one electron (unpaired electron) in the outermost orbital are particularly preferred because they easily form a SOMO with the first organic compound.

[0108] Metals with low melting points that can be deposited by vacuum deposition are preferred because they easily form mixed layers with organic compounds. Specifically, for example, metals belonging to Groups 11 and 13 have low melting points and are therefore suitable for vacuum deposition. Furthermore, metals belonging to Groups 11 and 13 are preferred because they are stable to atmospheric oxygen and water.

[0109] <First Organic Compound> As the first organic compound, an organic compound including a π-electron-deficient heteroaromatic ring can be used. In addition, in order for the first organic compound to interact with the metal and act as an electron donor (electron donor) to the second organic compound, the π-electron-deficient heteroaromatic ring preferably has a non-shared electron pair, and the non-shared electron pair preferably has electron donating properties. That is, the first organic compound preferably includes a basic π-electron-deficient heteroaromatic ring. In addition, nitrogen has a high electronegativity and is therefore easy to interact with the metal. In addition, since nitrogen can form a conjugated bond in an organic compound, by using nitrogen for molecules, especially for heteroaromatic rings, an organic compound with high carrier transport properties can be achieved. Therefore, the first organic compound preferably includes a heteroaromatic ring containing nitrogen. Note that the heteroaromatic ring is more preferably an even-numbered ring such as a six-membered ring or an eight-membered ring. By adopting this structure, the non-shared electron pair on nitrogen does not involve conjugation, and therefore easily interacts with the metal. In addition, in order to smoothly inject and transport electrons from the electron injection layer to the electron transport layer, the first organic compound has electron transport properties, so it is preferred. Specifically, for example, the first organic compound preferably includes a pyridine ring.

[0110] In addition, the first organic compound is preferably a material comprising two or more π-deficient electron-type heteroaromatic rings having non-shared electron pairs and the two or more π-deficient electron-type heteroaromatic rings are bonded or fused to each other. Thus, when the metal or metal compound as a bidentate ligand or a multidentate ligand interacts with the first organic compound and the second organic compound, it becomes stable, and thus an electron injection layer that is not easily degraded even after a photolithography process accompanied by atmospheric exposure can be formed. Specifically, for example, the first organic compound preferably includes a heteroaromatic ring comprising two or more pyridine rings. Among them, the nitrogen atom of the organic compound having a bipyridine skeleton is easily coordinated with the metal and is therefore easily interacted with the metal or metal compound, so it is preferred.

[0111] Furthermore, the phenanthroline ring is preferred due to its rigidity and high stability. In particular, among the phenanthroline rings, the two nitrogen atoms in the organic compound having a 1,10-phenanthroline ring can coordinate to the metal, and thus easily interact with the metal or metal compound, making it preferred.

[0112] Furthermore, the first organic compound may have a structure in which a plurality of phenanthroline rings are linked by a single bond or via a divalent group. Specific examples of the divalent group include an alkylene group and an arylene group.

[0113] An alkylene group represents a divalent group obtained by removing two hydrogen atoms from an alkane. Specific examples of the alkylene group include divalent groups having a structure obtained by removing one hydrogen atom from the specific examples of the alkyl group described below.

[0114] An arylene group represents a divalent group formed by removing two hydrogen atoms from an aromatic hydrocarbon. Specific examples include divalent groups having a structure in which one hydrogen atom is removed from the specific examples of aryl groups described below. The arylene group may further have a substituent, and specific examples of such substituents include an alkyl group, an alkoxy group, and a phenyl group.

[0115] Furthermore, the first organic compound preferably has an electron-donating substituent. This allows the first organic compound to have a high HOMO energy level and a high LUMO energy level, thereby increasing the difference between the LUMO energy levels of the first organic compound and the second organic compound. Furthermore, the intermediate layer can be further stabilized during the interaction between the metal or metal compound, the first organic compound, and the second organic compound, thereby forming an electron injection layer that is not easily degraded even after a photolithography process involving atmospheric exposure.

[0116] In addition, as the first organic compound, it is more preferred to use an organic compound comprising a phenanthroline ring with an electron donating group. In particular, by introducing an electron donating group on 1,10-phenanthroline ring, the electron density of the phenanthroline ring can be improved and the efficiency of the interaction with the metal can be improved. Furthermore, preferably, at least one of positions 4 and 7 of the 1,10-phenanthroline ring has an electron donating group. By introducing an electron donating group on positions 4 and 7, the electron density of the nitrogen-atoms at positions 1 and 10 of the para position can be improved. In addition, the steric hindrance around the nitrogen-atoms at positions 1 and 10 can be avoided, and the electron density around this can be improved. Therefore, it is possible to easily interact with the metal, so it is preferred.

[0117] As the specific example of the electron-donating group, alkyl, alkoxy, aryloxy, alkylamino, arylamino, heterocyclic amino etc. can be enumerated.But, the electron-donating group preferably introduced on the π-deficient electron type heteroaromatic ring such as phenanthroline ring is not limited thereto.As long as it is by introducing the base that can improve the electron density of the π-deficient electron type heteroaromatic ring on the π-deficient electron type heteroaromatic ring such as phenanthroline ring, it is possible to use it as the electron-donating group.In addition, the electron-donating group can also be introduced into the π-deficient electron type heteroaromatic ring such as phenanthroline ring through the arylene group such as phenylene, and the arylene group is preferably p-phenylene.

[0118] Alkyl refers to an alkane (C n H 2n+2 ) is a monovalent group obtained by removing one hydrogen atom. Specific examples of the alkyl 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.

[0119] An alkoxy group represents a monovalent group having a structure in which an alkyl group is bonded to an oxygen atom. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, an isobutoxy group, a tert-butoxy group, an n-pentoxy group, an isopentoxy group, a sec-pentoxy group, a tert-pentoxy group, a neopentoxy group, an n-hexoxy group, an isohexoxy group, a sec-hexoxy group, a tert-hexoxy group, and a neohexoxy group.

[0120] An aryloxy group represents a monovalent group having a structure in which an aryl group is bonded to an oxygen atom. An aryl group represents a monovalent group formed by removing a hydrogen atom from one of the ring carbon atoms of a monocyclic or polycyclic aromatic compound. Specific examples of the aryloxy group include a phenoxy group, an o-tolyloxy group, an m-tolyloxy group, a p-tolyloxy group, a mesityloxy group, an o-biphenyloxy group, an m-biphenyloxy group, a p-biphenyloxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, and a 2-fluorenyloxy group. The aryloxy group may further have a substituent, and specific examples of such a substituent include an alkyl group, an alkoxy group, and a phenyl group.

[0121] Alkylamino groups represent monovalent groups in which one or two alkyl groups are bonded to the nitrogen atom of a primary or secondary amine, with one hydrogen atom removed. Specific examples of alkylamino groups include dimethylamino and diethylamino groups.

[0122] An arylamino group represents a monovalent group formed by removing one hydrogen atom from the nitrogen atom of a primary or secondary amine in which one or two aryl groups are bonded to the nitrogen atom. Specific examples of arylamino groups include diphenylamino, bis(α-naphthyl)amino, and bis(m-tolyl)amino. The arylamino group may further have a substituent, and specific examples of such substituents include alkyl groups, alkoxy groups, and phenyl groups.

[0123] Furthermore, an amino group having a structure in which both an alkyl group and an aryl group are bonded to a nitrogen atom may be referred to as an alkylamino group or an arylamino group. Specific examples of such an amino group include N-methyl-N-phenylamino group and the like.

[0124] A heterocyclic amino group represents a monovalent group formed by removing a hydrogen atom from one of the nitrogen atoms forming a ring of a heterocyclic amine. Note that, herein, a heterocyclic amine refers to a monocyclic or polycyclic heterocyclic compound, and represents a compound in which at least one of the ring atoms is a nitrogen atom bonded to a hydrogen atom. Specific examples of heterocyclic amino groups 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 such a substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0125] [Chemical Formula 3]

[0126] Note that, when the heterocyclic amino group has aromaticity and the non-shared electron pair of nitrogen atom contributes to aromaticity, compared with the case where the non-shared electron pair of nitrogen atom does not contribute to aromaticity, the electron donating property to the phenanthroline ring is sometimes reduced. Therefore, in the above-mentioned heterocyclic amino group, it is more preferred to use the heterocyclic amino group in which the non-shared electron pair of nitrogen atom does not contribute to aromaticity. Specifically, the base represented by structural formula (R-1), structural formula (R-2), structural formula (R-3), structural formula (R-4), structural formula (R-5), structural formula (R-8), structural formula (R-9), structural formula (R-10), structural formula (R-12), structural formula (R-14), structural formula (R-15), structural formula (R-16), structural formula (R-17) or (R-21) is more preferred as an electron donating group. Among them, the groups represented by structural formula (R-3), structural formula (R-4), structural formula (R-8) or structural formula (R-21) have high electron donating properties and can further increase the electron density of the phenanthroline ring, so they are preferred.

[0127] Specific examples of the electron-donating group include groups represented by the following structural formulas (R-27) and (R-28).

[0128] [Chemical Formula 4]

[0129] Note that the organic compound containing a π-electron-deficient heteroaromatic ring that can be used as the first organic compound may also have both the above-mentioned electron-donating group and a substituent other than the above-mentioned electron-donating group. Specific examples of substituents that can be introduced into the π-electron-deficient heteroaromatic ring other than the above-mentioned electron-donating group include aryl groups. Specific examples of aryl groups include phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, o-biphenyl, m-biphenyl, p-biphenyl, 1-naphthyl, 2-naphthyl, and 2-fluorenyl. The aryl group may also have a substituent, and specific examples of such substituents include alkyl, alkoxy, and phenyl groups.

[0130] Furthermore, the first organic compound may have a structure in which a plurality of phenanthroline rings are linked by a single bond or via a divalent group. Specific examples of the divalent group include an alkylene group and an arylene group.

[0131] Specific examples of organic compounds including a π-electron-deficient heteroaromatic ring that can be used as the first organic compound are shown by structural formulas (100) to (112). Note that the organic compound that can be used as the first organic compound is not limited thereto.

[0132] [Chemical Formula 5]

[0133] Structural formula (100) is 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as Pyrrd-Phen). Structural formula (103) is 4,7-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidin-1-yl)-1,10-phenanthroline (abbreviated as 4,7hpp2Phen). Structural formula (105) is 2,2'-(1,3-phenylene)bis[9-(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidin-1-yl)-1,10-phenanthroline] (abbreviated as mhppPhen2P). Structural formula (106) is 2-(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidin-1-yl)-9-phenyl-1,10-phenanthroline (abbreviated as 9Ph-2hppPhen). Structural formula (107) is 2,9-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidin-1-yl)-1,10-phenanthroline (abbreviated as 2,9hpp2Phen). Structural formula (111) is 4,7-bis(2,3,3a,4,5,6,7,7a-octahydro-1H-isoindol-2-yl)-1,10-phenanthroline (abbreviated as Hid2Phen). Structural formula (112) is 4,7-bis[4-(1-pyrrolidinyl)phenyl]-1,10-phenanthroline (abbreviated as: PrdP2Phen).

[0134] Furthermore, it is preferable that the negative minimum value of the electrostatic potential (ESP) of the first organic compound is small (the negative absolute value is large) because the stability of the interaction with the metal is improved. In the organic compound including the lack of π electron type heteroaromatic ring, electrostatic potential around the nitrogen atom of the lack of π electron type heteroaromatic ring tends to have a negative value, but by introducing an electron-donating group on the lack of π electron type heteroaromatic ring, the electrostatic potential around the nitrogen atom of the lack of π electron type heteroaromatic ring can be further reduced (increase the negative absolute value). Electrostatic potential refers to the interaction energy of the positive point charge with unit electric charge and the electron distribution interaction of the molecule. In addition, the value of electrostatic potential also changes according to the threshold value of electron density distribution. In order to improve the efficiency of the interaction with metal, the minimum value of the electrostatic potential of the first organic compound is preferably less than the minimum value (large in the negative direction) of the electrostatic potential of the phenanthroline ring without substituent. Specifically, when the threshold value of the electron density distribution in the atomic unit system is 0.0004e / a. 3 When the minimum value of the electrostatic potential is preferably -0.085E h (E h represents the Hartree energy (1E h =27.211eV)) or less, more preferably -0.090E h In addition, when the threshold value of electron density distribution is 0.003e / a0 3 When the minimum value of the electrostatic potential is preferably -0.12E h Below, more preferably -0.13E h the following.

[0135] <<Estimating the Properties of the First Organic Compound Using Quantum Chemical Calculations>> The minimum value of the electrostatic potential (ESP) of the above-mentioned organic compounds that can be used as the first organic compound was estimated by quantum chemical calculation.

[0136] Gaussian 09 was used as a quantum chemical calculation program. Calculations were performed using an SGI8600 manufactured by HPE. Density functional theory (DFT) was used to calculate the most stable structure of the first organic compound in the ground state. 6-311G (d, p) was used as the basis function, and B3LYP was used as the functional.

[0137] The following table shows the analysis results of the electrostatic potential in the ground state of the first organic compound. The 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 the electrostatic potential varies depending on the threshold value of the electron density distribution. The following table shows the analysis results in atomic units, with the threshold value of the electron density distribution set to 0.0004e / a. 3 or 0.003e / a0 3The electrostatic potential of the electron density distribution when .

[0138] [Table 5]

[0139] Note that the structural formulas of the organic compounds represented by structural formulas (101) to (107), structural formula (111), and structural formula (112), BPhen, mPPhen2P, NBPhen, and Phen in the table shown below as organic compounds that can be used as the first organic compound are shown.

[0140] [Chemical Formula 6]

[0141] As can be seen from the above table, the threshold value of the electron density distribution in the atomic unit system in the organic compounds represented by structural formula (100) to structural formula (103), structural formula (111) and structural formula (112) is 0.0004e / a0 3 The minimum ESP value is -0.085E h On the other hand, it is known that the minimum ESP value of the organic compounds represented by the structural formula (104) to the structural formula (107) is greater than -0.085E h .

[0142] It can be seen that the organic compounds represented by structural formulas (100) to (103), (111) and (112) have electron-donating groups at positions 4 and 7 of the 1,10-phenanthroline ring and therefore have the most preferred values.

[0143] The organic compound represented by structural formula (104) has electron-donating groups at the 4- and 7-positions of the 1,10-phenanthroline ring, but uses an N-carbazolyl group as the electron-donating group. In the N-carbazolyl group, the unshared electron pair of the nitrogen atom contributes to aromaticity. Therefore, compared to groups in which the unshared electron pair of the nitrogen atom does not contribute to aromaticity, the electron-donating capacity to the phenanthroline ring is reduced. Consequently, the minimum ESP value is less likely to decrease, leading to the above-mentioned results.

[0144] The organic compounds represented by structural formula (105) to structural formula (107) are organic compounds having electron-donating groups at the 2-position and 9-position of the 1,10-phenanthroline ring. The electron-donating groups introduced at the 2-position and 9-position have low electron-donating properties to the nitrogen at the 1-position and 10-position of the phenanthroline ring. Therefore, the electron-donating groups in the 1,10-phenanthroline ring are preferably located at the 4-position and 7-position.

[0145] Note that the LUMO energy level of the second organic compound is preferably lower than that of the first organic compound. This facilitates electron transfer from the donor level formed by the first organic compound and the metal to the second organic compound. Furthermore, the second organic compound preferably has electron-transporting properties, and to this end, the LUMO energy level of the second organic compound is preferably lower than that of the first organic compound.

[0146] For example, the LUMO energy level of the first organic compound is preferably greater than -3.0 eV and less than -2.0 eV, more preferably greater than -2.7 eV and less than -2.0 eV. In addition, the LUMO energy level of the second organic compound is preferably greater than -3.0 eV and less than -2.0 eV, more preferably greater than -3.0 eV and less than -2.5 eV. This makes it easy to supply electrons from the donor level formed by the first organic compound and the metal to the second organic compound. In addition, this facilitates electron transport in the second organic compound.

[0147] Note that the HOMO and LUMO levels of organic compounds 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.

[0148] In addition, when the basicity of the first organic compound is high, the hole transport property of the electron injection layer can be significantly reduced by interacting with holes to prevent holes from being transported from the electron injection layer to the electron transport layer, thereby obtaining a light-emitting device with high efficiency, which is preferred. Specifically, the acidity coefficient pK a It is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more.

[0149] In addition, the acidity coefficient pK of organic compounds a If unknown, investigate the acidity coefficient pK of each skeleton of the organic compound. a , the largest acidity coefficient pK a Considered as the acidity coefficient pK of the organic compound a .

[0150] Alternatively, the acidity coefficient can be calculated. For example, the acidity coefficient pK can be calculated using the following calculation method: a .

[0151] As the initial structure of the molecular structure of each molecule used as a calculation model, the most stable structure (singlet ground state) obtained by first-principles calculation was adopted.

[0152] As the first principles calculations above, use Jaguar, a quantum chemical calculation software manufactured by Inc., calculates the most stable structure in the singlet ground state using density functional theory (DFT). 6-31G** is used as the basis function and B3LYP-D3 is used as the functional function. Maestro GUI manufactured by Inc. performs conformational analysis and sampling using Mixed torsional / Low-mode sampling.

[0153] In pK a In the calculation, one or more atoms in each molecule were designated as basic sites, and the Macro Model was used to explore the stable structure of the protonated molecule in water. The conformational isomer with the lowest energy obtained by conformational exploration using the OPLS2005 force field was used. The pK values of Jaguar were used. a The calculation module uses B3LYP / 6-31G* to optimize the structure, and then performs single-point calculations with cc-pVTZ(+) to calculate the pK using empirical corrections for functional groups. a In molecules where more than one atom is assigned as a basic site, the largest value among the results obtained is used as the pK a The obtained pK a The value of .

[0154] 2,9hpp2Phen acidity coefficient pK a The acidity coefficient pK is 13.35, 4, 7hpp2Phen a The acidity coefficient pK of Pyrrd-Phen is 13.42. a The acidity coefficient pK of mPPhen2P is 11.23. a The acidity coefficient pK of NBPhen is 5.16. a The acidity coefficient pK of BPhen is 5.59. a It is 5.62.

[0155] <Second Organic Compound> The electron injection layer includes, in addition to the metal or metal compound and the first organic compound, a second organic compound including two or more heteroaromatic rings bonded or fused to each other, wherein the two or more heteroaromatic rings include a total of three or more heteroatoms. Furthermore, the second organic compound functions as a multidentate ligand, with two or more of the three or more heteroatoms interacting with the metal or metal compound.

[0156] Including a second organic compound can improve heat resistance and electron transport properties. In one embodiment of the present invention, when the π-electron-deficient heteroaromatic ring included in the first organic compound is a first π-electron-deficient heteroaromatic ring and the π-electron-deficient heteroaromatic ring included in 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 preferably include different rings.

[0157] In addition, as the second π-electron-deficient heteroaromatic ring, it is preferred to use 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., among which the diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or triazine ring is electrochemically stable and has high electron transport properties, so it is preferred.

[0158] As the organic compound used as the second organic compound, for example, an organic compound represented by the following general formula (G1-1) can be used.

[0159] [Chemical Formula 7]

[0160] In the above general formula (G1-1), A 1 、A 2 and A 3 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 、A 2 and A 3 They may also form a condensed ring.

[0161] Organic compounds represented by general formula (G1-1) have conjugated double bonds formed by the N groups on the heteroaromatic ring arranged in the order of NCCN, and function as tridentate or higher ligands that interact with metals. Organic compounds with this structure readily interact with metals and are therefore suitable for use in electron injection layers.

[0162] In the above general formula (G1-1), as A 1 、A 2 and A 3The substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by , for example, a heteroaromatic ring having a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthyridine ring, bipyridine ring, phenanthridine ring, phenanthroline ring, anthridine ring (anthyridine ring), azafluoranthene ring), a heteroaromatic ring having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, cinnoline ring, pteridine ring, phenazine ring), a heteroaromatic ring having a triazine skeleton, a heteroaromatic ring having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. Note that A 1 、A 2 and A 3 The substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by is not limited thereto. 1 、A 2 and A 3 They can also form fused rings with each other. For example, A 1 With A 2 They may be bonded to each other to form a phenanthroline ring.

[0163] In addition, as the organic compound used as the second organic compound, an organic compound represented by the following general formula (G2-1) can be used.

[0164] [Chemical Formula 8]

[0165] In the general formula (G2-1), X 1 To X 6 Each independently represents carbon (C) or nitrogen (N), carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 4 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. Alternatively, in the general formula (G2-1), X 1 To X 6 They may be bonded to each other directly or through carbon atoms to form a condensed ring.

[0166] As in the organic compound represented by the general formula (G2-1), the organic compound having a function of interacting with a metal as a tridentate or higher ligand preferably includes at least one of a heteroaromatic ring having a pyridine skeleton, a heteroaromatic ring having a diazine skeleton, and a heteroaromatic ring having a triazine skeleton. These rings have excellent electrochemical stability, so a light-emitting device with good reliability can be provided. In addition, due to the excellent electron transport properties, a light-emitting device with a reduced driving voltage can be provided.

[0167] In addition, as the organic compound used as the second organic compound, an organic compound represented by the following general formula (G3-1) can be used.

[0168] [Chemical Formula 9]

[0169] In the general formula (G3-1), X 1 To X 4 Each independently represents carbon (C) or nitrogen (N), carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 6 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0170] In addition, as an organic compound that can be used as the second organic compound, an organic compound represented by the following general formula (G4-1) can be used.

[0171] [Chemical Formula 10]

[0172] In the general formula (G4-1), X 1 To X 5 Each independently represents carbon (C) or nitrogen (N), carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 5 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0173] Organic compounds having a pyridine skeleton are preferred because they have a high LUMO energy level. 1 and X 2 When carbon is represented, the organic compound has a pyridine skeleton and can form a composite material with a high SOMO level when interacting with a metal. In other words, an organic compound having a pyridine ring and capable of interacting as a tridentate or higher ligand can form an electron injection layer with high electron injection properties when interacting with a metal.

[0174] In addition, organic compounds having a diazine skeleton or a triazine skeleton are preferred because they are electrochemically stable and have high electron transport properties. 1 and X 2 When at least one of the rings represents nitrogen, the organic compound has a diazine or triazine skeleton and can form a stable composite material with high electron transport properties when interacting with a metal. In other words, an organic compound having a diazine ring or a triazine ring that functions as a tridentate or higher ligand can form a highly reliable electron injection layer by interacting with a metal.

[0175] In addition, as the organic compound used as the second organic compound, for example, an organic compound represented by the following general formula (G1-2) can be used.

[0176] [Chemical Formula 11]

[0177] In the above general formula (G1-2), A 1 and A 2 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 and A 2 They can also form fused rings with each other, A 1 Contains two or more nitrogen atoms.

[0178] Organic compounds represented by general formula (G1-2) have conjugated double bonds formed by the N groups on the heteroaromatic ring arranged in the order of NCCN, and function as bidentate or higher-order ligands that interact with metals. Organic compounds with this structure readily interact with metals and are therefore suitable for use in electron injection layers.

[0179] In the above general formula (G1-2), as A 1The substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by , for example, a heteroaromatic ring having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, cinnoline ring, pteridine ring, phenazine ring), a heteroaromatic ring having a triazine skeleton, a heteroaromatic ring having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring) and the like. As the heteroaromatic ring represented by A 2 The substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by , for example, a heteroaromatic ring having a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthyridine ring, bipyridine ring, phenanthridine ring, phenanthroline ring, anthridine ring, azafluoranthene ring), a heteroaromatic ring having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, cinnoline ring, pteridine ring, phenazine ring), a heteroaromatic ring having a triazine skeleton, a heteroaromatic ring having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. Note that A 1 and A 2 The substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by is not limited thereto. 1 and A 2 They can also form fused rings with each other. For example, A 1 With A 2 They may be bonded to each other to form a pyrazinoquinoxaline ring.

[0180] In addition, as the organic compound used as the second organic compound, an organic compound represented by the following general formula (G2-2) can be used.

[0181] [Chemical Formula 12]

[0182] In the general formula (G2-2), X 1 To X 4 At least one of them represents nitrogen (N), and the rest independently represent carbon (C) or nitrogen (N), carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 4 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. Alternatively, in the general formula (G2-2), X1 To X 4 They may be bonded to each other directly or through carbon atoms to form a condensed ring.

[0183] As in the organic compound represented by the general formula (G2-2), the organic compound having a function of interacting with a metal as a bidentate or higher ligand more preferably includes a heteroaromatic ring having a diazine skeleton or a heteroaromatic ring having a triazine skeleton. These rings have excellent electrochemical stability, so a light-emitting device with good reliability can be provided. In addition, due to the excellent electron transport properties, a light-emitting device with a reduced driving voltage can be provided.

[0184] In addition, as the organic compound used as the second organic compound, an organic compound represented by the following general formula (G3-2) can be used.

[0185] [Chemical Formula 13]

[0186] In the general formula (G3-2), X 1 and X 2 One of the R represents nitrogen (N), and the other represents carbon (C) or nitrogen (N), and the carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 6 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0187] In addition, as an organic compound that can be used as the second organic compound, an organic compound represented by the following general formula (G4-2) can be used.

[0188] [Chemical Formula 14]

[0189] In the general formula (G4-2), X 1 To X 3 At least one of them represents nitrogen (N), and the rest independently represent carbon (C) or nitrogen (N), carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 5Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0190] Organic compounds having a pyridine skeleton are preferred because they have a high LUMO energy level. 1 and X 2 and X represented by the general formula (G3-2) 1 When carbon is represented, the organic compound has a pyridine skeleton and can form a composite material with a high SOMO level when interacting with a metal. In other words, an organic compound having a pyridine ring and capable of interacting as a bidentate or higher ligand can form an electron injection layer with high electron injection properties when interacting with a metal.

[0191] In addition, organic compounds having a diazine skeleton or a triazine skeleton are preferred because they are electrochemically stable and have high electron transport properties. 1 and X 2 At least one of and X represented by the general formula (G3-2) 1 When represents nitrogen, the organic compound has a diazine or triazine skeleton, and thus can form a stable composite material with high electron transport properties when interacting with a metal. In other words, an organic compound having a diazine or triazine ring that functions as a bidentate or higher-order ligand can form a highly reliable electron injection layer by interacting with a metal.

[0192] Specific examples of the organic compound used as the second organic compound and the organic compound including a complex aromatic ring represented by the above-mentioned general formula (G1-1) to general formula (G4-2) are shown below.

[0193] [Chemical Formula 15]

[0194] [Chemical Formula 16]

[0195] In addition, examples of substituents that can be used in the above general formulas (G1-1) to (G4-2) include alkyl groups having 1 to 10 carbon atoms, cycloalkyl groups having 3 to 10 carbon atoms, aryl groups having 6 to 30 carbon atoms, arylene groups having 6 to 30 carbon atoms, and heteroaryl groups having 1 to 30 carbon atoms. Note that some or all of the hydrogen atoms may be deuterium. The groups that can be used in the above general formulas are not limited to the following specific examples.

[0196] Specific examples of the alkyl group having 1 to 10 carbon atoms 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, 2,3-dimethylbutyl, and 1-ethylhexyl.

[0197] Specific examples of the cycloalkyl group having 3 to 10 carbon atoms include cyclopropyl, cyclobutyl, methylcyclobutyl, cyclopentyl, methylcyclopentyl, isopropylcyclopentyl, tert-butylcyclopropyl, cyclohexyl, methylcyclohexyl, isopropylcyclohexyl, tert-butylcyclohexyl, cycloheptyl, methylcycloheptyl, isopropylcycloheptyl, cyclooctyl, methylcyclooctyl, isopropylcyclohexyl, cyclononyl, methylcyclononyl, cyclodecyl, and adamantyl.

[0198] Specific examples of the aryl group having 6 to 30 carbon atoms include phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, o-biphenyl, m-biphenyl, p-biphenyl, 1-naphthyl, 2-naphthyl, fluorenyl, 9,9-dimethylfluorenyl, spirobifluorenyl, phenanthrenyl, anthracenyl, and fluoranthenyl. When the aryl group having 6 to 30 carbon atoms has a substituent, the substituent includes an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and a phenyl group.

[0199] Specific examples of the arylene group having 6 to 30 carbon atoms include phenylene, biphenyl-diyl, naphthalene-diyl, fluorene-diyl, acenaphthene-diyl, anthracene-diyl, phenanthrene-diyl, terphenyl-diyl, triphenylene-diyl, naphthacene-diyl, benzanthracene-diyl, pyrene-diyl, and spirobi[9H-fluorene]-diyl. When the arylene group having 6 to 30 carbon atoms has a substituent, the substituent includes an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and a phenyl group.

[0200] A heteroaryl group having 1 to 30 carbon atoms refers to a monovalent group formed by removing one hydrogen atom from one of the ring carbon atoms of a monocyclic or polycyclic heteroaromatic compound having 1 to 30 carbon atoms. Specific examples of heteroaryl groups having 1 to 30 carbon atoms include 1,3,5-triazin-2-yl, 1,2,4-triazin-3-yl, pyrimidin-4-yl, pyrazin-2-yl, 2-pyridyl, 3-pyridyl, 4-pyridyl, carbazolyl, dibenzofuranyl, dibenzothiophenyl, benzonaphthofuranyl, benzonaphthothiophenyl, indolocarbazolyl, benzofuranocarbazolyl, benzothiophenocarbazolyl, indenocarbazolyl, and dibenzocarbazolyl. When the heteroaryl group has a substituent, the substituent may include an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and a phenyl group.

[0201] Specific examples of the organic compound used as the second organic compound and the organic compounds represented by the above-mentioned general formula (G1-1) to general formula (G4-2) are shown below.

[0202] [Chemical Formula 17]

[0203] [Chemical Formula 18]

[0204] [Chemical Formula 19]

[0205] Note that the LUMO energy level of the second organic compound is preferably lower than that of the first organic compound. This facilitates electron donation from the donor level formed by the first organic compound and the metal or metal compound to the second organic compound. Furthermore, the second organic compound preferably has electron-transporting properties, and to this end, the LUMO energy level of the second organic compound is preferably lower than that of the first organic compound.

[0206] The LUMO energy level of the second organic compound is preferably from -3.2 eV to -2.0 eV, more preferably from -3.1 eV to -2.0 eV, and even more preferably from -3.0 eV to -2.5 eV. Furthermore, the LUMO energy level of the first organic compound is preferably from -3.0 eV to -2.0 eV, more preferably from -2.7 eV to -2.0 eV.

[0207] This facilitates the supply of electrons from the donor level formed by the first organic compound and the metal or metal compound to the second organic compound, and also facilitates the transport of electrons in the second organic compound.

[0208] 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 0.60 eV lower than the LUMO energy level of the first organic compound, preferably a value of 0.50 eV or more and 0.20 eV or less than the LUMO energy level of the first organic compound, more preferably a value of 0.50 eV or more and 0.25 eV or less than the LUMO energy level of the first organic compound, more preferably a value of 0.50 eV or more and 0.30 eV or less than the LUMO energy level of the first organic compound, more preferably a value of 0.50 eV or more and 0.35 eV or less than the LUMO energy level of the first organic compound, and further preferably a value of 0.50 eV or more and 0.40 eV or less than the LUMO energy level of the first organic compound.

[0209] That is, when the LUMO energy level of the first organic compound is expressed as "LUMO1 (eV)" and the LUMO energy level of the second organic compound is expressed as "LUMO2 (eV)", LUMO2 preferably satisfies the following formula. LUMO1-0.50≤LUMO2≤LUMO1-0.20

[0210] Furthermore, it is more preferable that LUMO2 satisfies the following formula. LUMO1-0.50≤LUMO2≤LUMO1-0.25

[0211] Furthermore, it is more preferable that LUMO2 satisfies the following formula. LUMO1-0.50≤LUMO2≤LUMO1-0.30

[0212] Furthermore, it is more preferable that LUMO2 satisfies the following formula. LUMO1-0.50≤LUMO2≤LUMO1-0.35

[0213] Furthermore, it is more preferable that LUMO2 satisfies the following formula. LUMO1-0.50≤LUMO2≤LUMO1-0.40

[0214] When the LUMO2 is within the above range, a light-emitting device according to one embodiment of the present invention can be realized with low driving voltage and excellent characteristics, regardless of whether or not a photolithography step involving atmospheric exposure of the EL layer is performed. Furthermore, a light-emitting device with high reliability can be realized.

[0215] As the second organic compound, an organic compound having electron transport properties can be used. As the organic compound having electron transport properties, an organic compound having an electron mobility of 1×10- - 7 cm 2 It is more preferable to use a 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.

[0216] The second organic compound preferably has a carbon number of 25 to 100. This carbon number allows for an organic compound with good sublimation properties, thereby suppressing thermal decomposition of the organic compound during vacuum deposition and achieving good material utilization efficiency.

[0217] In addition, it is preferable to use a second organic compound having a glass transition temperature T g The organic compound is 100° C. or higher. This allows the electron injection layer to have high heat resistance and be less likely to crystallize. Therefore, a layer that is less likely to crystallize even when a portion of the organic compound layer is processed by photolithography can be realized.

[0218] In addition, as the second organic compound, the acidity coefficient pK a An organic compound having a molecular weight of less than 4. This can reduce the water solubility of the second organic compound, thereby improving the resistance to water and chemical solutions used in the photolithography process.

[0219] and acidity coefficient pK a The water solubility of organic compounds with a pH of 4 or more is compared to the acidity coefficient pK a The water solubility of organic compounds with a pH less than 4 is low. a Compared with the case where an organic compound with a pK value of 4 or more is used as the second organic compound, the acidity coefficient pK a Using an organic compound with a molar ratio of less than 4 as the second organic compound can improve the water resistance of the electron injection layer. Furthermore, during the manufacturing process, it can prevent problems such as the electron injection layer peeling off from other layers. This can also prevent defects that could cause defects in the light-emitting device.

[0220] In addition, the acidity coefficient pK of organic compounds a If unknown, investigate the acidity coefficient pK of each skeleton of the organic compound. a , the largest acidity coefficient pK a Considered as the acidity coefficient pK of the organic compound a .

[0221] Furthermore, when the first layer contains a second organic compound in addition to the metal or metal compound and the first organic compound, interaction between the materials occurs efficiently, which can be confirmed by measuring the spin density using electron spin resonance (ESR).

[0222] For example, the spin density measured by ESR of a film comprising a metal or metal compound and a first organic compound is preferably higher than the spin density measured by ESR of a film comprising a metal or metal compound and a second organic compound. Furthermore, the spin density measured by ESR of a film comprising a metal or metal compound, a first organic compound, and a second organic compound is preferably higher than the spin density measured by ESR of a film comprising only any two of the metal or metal compound, the first organic compound, and the second organic compound. In this case, it can be confirmed that the interaction between the materials is efficiently generated.

[0223] More specifically, in a film containing a metal or a metal compound and a first organic compound, the spin density of a signal observed at a g value of approximately 2.00 by an electron spin resonance method is preferably 5×10 16 spins / cm 3 More than 1×10 17 spins / cm 3 More than 1×10 18 spins / cm 3 More than 1×10 19 spins / cm 3 More than 1×10 20 spins / cm 3 In this case, it can be confirmed that the interaction between the materials is efficiently generated in the layer containing the combination of the metal or metal compound and the first organic compound. Alternatively, in the film containing the metal or metal compound, 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 than 1×10 17 spins / cm 3 More than 1×10 18 spins / cm 3 More than 1×10 19 spins / cm 3 More than 1×10 20spins / cm 3 In this case, it can be confirmed that the interaction between the materials in the layer containing the combination of the metal or metal compound, the first organic compound, and the second organic compound occurs more efficiently than in the layer containing only two of these materials. In this case, the spin density of the mixed film containing the metal or metal compound and the second organic compound, for example, caused by the signal observed at a g value of 2.00 by the electron spin resonance method, is 2×10 16 spins / cm 3 Hereinafter, the spin density of a mixed film containing the first organic compound and the second organic compound, for example, resulting from a signal observed at a g value of approximately 2.00 by electron spin resonance, is 2×10 16 spins / cm 3 the following.

[0224] In the first layer, the metal or metal compound is preferably 0.1 or more and 10 or less of the first organic compound (or the sum of the first organic compound and the second organic compound) in a molar ratio, more preferably 0.2 or more and 5 or less, and further preferably 0.5 or more and 2 or less. Alternatively, it 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 in a volume ratio. By including a first layer comprising a metal or metal compound and a first organic compound (or a first organic compound and a second organic compound) in such a ratio, an electron injection 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 first organic compound is preferably 0.1 or more and 10 or less of the second organic compound in a volume ratio, 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 in such a ratio, an electron injection 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 highly reliable organic EL device can be provided.

[0225] In addition, the thickness of the first layer is preferably from 2 nm to 20 nm, more preferably from 5 nm to 10 nm. When the first layer has a laminated structure of a layer of a metal or metal compound and a layer comprising a first organic compound, the thickness of the metal or metal compound layer is preferably from 0.1 nm to 5 nm, more preferably from 0.2 nm to 2 nm. In addition, when the first layer has a laminated structure of a layer of a metal or metal compound and a layer comprising a first organic compound, the thickness of the layer comprising the first organic compound is preferably from 2 nm to 20 nm, more preferably from 5 nm to 10 nm.

[0226] By using the second organic compound, a composite material obtained by mixing metal, the first organic compound, and the second organic compound can function well, thereby providing a light-emitting device exhibiting high luminous efficiency.

[0227] <Second Electrode> The second electrode is an electrode that forms a pair with the first electrode. The light-emitting device includes the first electrode, the second electrode, and an organic compound layer positioned between the first and second electrodes. Preferably, the organic compound layer includes a light-emitting layer and an electron injection layer, the electron injection layer being positioned between the light-emitting layer and the second electrode, and being in contact with the second electrode.

[0228] The second electrode preferably uses a conductive metal oxide such as indium oxide-tin oxide (ITO), 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). In addition, for example, metal materials such as gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), aluminum (Al), yttrium (Y), zirconium (Zr), tantalum (Ta), silver (Ag) and magnesium (Mg) or alloy materials containing the metal materials can also be used. Alternatively, nitrides of metal materials (for example, titanium nitride) can be cited. These materials are not easily degraded by the photolithography process, so even after the photolithography process, a light-emitting device with good characteristics can be obtained.

[0229] By making the second electrode light-transmissive, a top-emitting light-emitting device can be realized in which light is emitted from the second electrode side. In the case of a bottom-emitting light-emitting device, the second electrode is preferably an electrode with high reflectivity for visible light (40% to 100%, preferably 70% to 100%).

[0230] In addition, some of these materials are generally not easily used as cathodes due to their high work function. However, in one embodiment of the present invention, by using a second electrode and an electron injection layer having the above structure, a light-emitting device with excellent characteristics can be provided.

[0231] In this way, the electron injection layer includes, in addition to the metal or metal compound and the first organic compound, two or more heteroaromatic rings bonded or fused to each other, and the two or more heteroaromatic rings include a second organic compound having a total of three or more heteroatoms. By using this electron injection layer in an organic EL device of one embodiment of the present invention, an organic EL device having good characteristics can be achieved even after the process of exposing the organic compound layer to the atmosphere after forming the second electrode. That is, by using the structure of one embodiment of the present invention, an organic EL device with good characteristics manufactured using a photolithography method including a process of exposing the organic compound layer to the atmosphere can be achieved. Specifically, an electron injection layer resistant to oxygen and water in the atmosphere, as well as water and chemical solutions used in the process of the photolithography method, can be formed. Thus, one embodiment of the present invention can provide a light-emitting device with high moisture resistance, high water resistance, high oxygen resistance, high chemical resistance, low driving voltage, and high luminous efficiency.

[0232] Thus, a display device with ultra-high definition and excellent characteristics can be provided.

[0233] In addition, although the light-emitting device of one embodiment of the present invention is particularly preferably used as a light-emitting device through a photolithography process, even if it is used as a light-emitting device manufactured without a photolithography process, its stability to the atmosphere is high, so the yield is improved, and the atmosphere management in the manufacturing process does not need to be too strict, which helps to reduce costs.

[0234] Implementation Method 2 In this embodiment, a light-emitting device according to one embodiment of the present invention is described in detail.

[0235] Figure 1A This is a schematic diagram of a light-emitting device according to one embodiment of the present invention. In this light-emitting device, a first electrode 101 is provided on an insulator 1000, and an organic compound layer 103 is provided between the first electrode 101 and the second electrode 102. The organic compound layer 103 includes at least a light-emitting layer 113 and an electron-injection layer 115. The light-emitting layer 113 contains a light-emitting substance. The light-emitting device according to one embodiment of the present invention emits light when a voltage is applied between the first electrode 101 and the second electrode 102.

[0236] like Figure 1A As shown, the organic compound layer 103 preferably includes functional layers such as a hole injection layer 111, a hole transport layer 112, and an electron transport layer 114 in addition to the light-emitting layer 113 and the electron injection layer 115. Furthermore, the organic compound layer 103 may include functional layers other than the aforementioned functional layers, such as a hole blocking layer, an exciton blocking layer, and an intermediate layer. Conversely, any of the aforementioned layers may not be provided.

[0237] In addition to the metal or metal compound and the first organic compound described in Embodiment 1, the electron injection layer 115 further includes a second organic compound including two or more heteroaromatic rings bonded or fused to each other, wherein the two or more heteroaromatic rings include a total of three or more heteroatoms. The specific structure of the electron injection layer 115 has been described in detail in Embodiment 1, and therefore, repeated description is omitted here.

[0238] In addition, the first electrode 101 and the second electrode 102 may be formed as a single-layer structure or a stacked-layer structure.

[0239] In addition, since the light-emitting device of one embodiment of the present invention is processed by photolithography after the second electrode 102 is formed, Figure 1A As shown in FIG. 1 , the end of the cross section of the second electrode 102 and the end of the cross section of the organic compound layer 103 are aligned in a direction substantially perpendicular to the surface of the insulator 1000, which is also one of the characteristics. The end of the second electrode 102 and the end of the organic compound layer 103 can be as follows Figure 1A and Figure 1B It is located inside the end of the first electrode 101, and can also be Figure 1C That is, it is located outside the first electrode 101.

[0240] The first electrode 101 is preferably formed using a metal, alloy, conductive compound, or mixture thereof having a large work function (specifically, 4.0 eV or more). Specifically, for example, indium oxide-tin oxide, indium oxide-tin oxide containing silicon or silicon oxide (ITSO), indium oxide-zinc oxide, indium oxide containing tungsten oxide and zinc oxide (IWZO), etc. can be cited. Although these conductive metal 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 forming 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 first electrode 101, 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 a nitride of a metal material (for example, titanium nitride) can be cited. In addition, the layer stacked thereon 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 its good reflectivity and can achieve a high resolution of thousands of ppi, so it is preferred. In addition, graphene can also be used as a material for the first electrode 101. In addition, by using a composite material that can constitute the hole injection layer 111 described later for a layer in contact with the anode (typically a hole injection layer), it is possible to select an electrode material without having to take into account the work function.

[0241] The hole injection layer 111 contacts the first electrode 101 and facilitates hole injection into the organic compound layer 103. Phthalocyanine compounds or complexes such as phthalocyanine (abbreviated as H2Pc) and copper phthalocyanine (abbreviated as CuPc) can be used; 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), etc.; or polymers such as poly(3,4-ethylenedioxythiophene) / (polystyrene sulfonic acid) (abbreviation: PEDOT / PSS) etc. are used to form the hole injection layer 111 .

[0242] Alternatively, the hole injection layer 111 may be formed of a substance having electron acceptor properties. Examples of the substance having electron acceptor properties include organic compounds having electron-withdrawing groups (halogen groups, cyano groups), such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated as F6-TCNNQ), and 2-(7-dicyanomethylidene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple hetero atoms, such as HAT-CN, are thermally stable and therefore preferred. In addition, [3]radialene derivatives containing electron-withdrawing groups (especially halogen groups such as fluorine groups, cyano groups, etc.) are particularly preferred because of their very high electron accepting properties. Specifically, they include: α,α',α"-1,2,3-cyclopropanetriylidene tris[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α,α',α"-1,2,3-cyclopropanetriylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], α,α',α"-1,2,3-cyclopropanetriylidene tris[2,3,4,5,6-pentafluorophenylacetonitrile]. As substances having electron accepting properties, in addition to the above-mentioned organic compounds, metal oxides, especially transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can also be used.

[0243] The hole-injection layer 111 is preferably formed using a composite material including the above-mentioned material having electron accepting properties and an organic compound having hole-transporting properties.

[0244] As the organic compound with hole transport properties 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 properties 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 having 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 any one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton is preferred, specifically a carbazole ring, a dibenzothiophene ring, or a ring in which these rings are further fused with an aromatic ring or a heteroaromatic ring.

[0245] This organic compound having hole-transporting properties preferably has any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, it can 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 the nitrogen of the amine via an arylene group. Note that when these organic compounds having hole-transporting properties include an N,N-bis(4-biphenyl)amino group, they are preferred because they can produce light-emitting devices with long lifetimes.

[0246] Specific examples of the organic compound having hole transport properties include N- (4-Biphenyl)-6, N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (BnfABP), N, N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4"-phenyltriphenylamine (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-( 4-(2-naphthyl)phenyl]-4',4"-diphenyltriphenylamine (abbreviated as: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4"-diphenyltriphenylamine (abbreviated as: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4"-diphenyltriphenylamine (abbreviated as: BBAβN Bi), 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;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 Phenylamine (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: T PBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviated as αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviated as αNBB1BP), 4,4'-diphenyl-4"-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviated as YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)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: PCBNBSF), N,N-bis(biphenyl-4-yl) -9,9'-spirobi[9H-fluorene]-2-amine (abbreviated as: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviated as: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviated as: oFBiSF), N- (Biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviated as BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBA1BP), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (Abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (Abbreviation: PCNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (Abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-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.

[0247] In addition, as materials with hole-transporting 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.

[0248] By forming the hole injection layer 111, hole injection properties can be improved, thereby obtaining a light-emitting device with low driving voltage.

[0249] Furthermore, among substances having electron acceptor properties, organic compounds having acceptor properties can be easily deposited by vapor deposition and are therefore easy-to-use materials.

[0250] The hole transport layer 112 is formed of 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.

[0251] 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), and 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 Compounds having an aromatic amine skeleton, such as 1,3-bis(N-carbazolyl)benzene (mCP), 4,4'-bis(N-carbazolyl)biphenyl (CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (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-3,3'-bi-9H-carbazole (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'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylene-2-yl) Compounds having a carbazole skeleton, such as -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, and 9-(triphenyl-2-yl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole; 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as DBT3P-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 compounds having a furan skeleton, such as 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). Among them, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton have high reliability and excellent hole transport properties and help reduce the driving voltage, so they are preferred. Note that as a material constituting the hole-transport layer 112 , any of the substances listed as the material having a hole-transport property for the composite material used for the hole-injection layer 111 can be used as appropriate.

[0252] The light-emitting layer 113 is a layer containing a light-emitting substance, preferably containing a light-emitting substance and a host material. Note that the light-emitting layer may also contain other materials. Alternatively, the light-emitting layer may be a stack of two or more layers having different compositions.

[0253] 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.

[0254] 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.

[0255] Examples thereof include 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl) -N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviated as: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviated as: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviated as: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9, 10-diphenyl-2-anthryl) triphenylamine (abbreviated as: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviated as: PCAPA), perylene, 2,5,8,11-tetra-tert-butyl perylene (abbreviated as: TBP), 4-(10-phenyl-9-anthryl)-4'- (9-Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as: PCBAPA), N,N″-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(, 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] (chrysene)-2,7,10, 15-tetramine (abbreviated as DBC1), coumarin 30, N-(9,10-diphenyl-2-anthracenyl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviated as 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthracenyl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviated as 2PCABPhA), N-(9,10-diphenyl-2-anthracenyl)-N,9-diphenyl-9H-carbazole-3-amine N-[9,10-bis(biphenyl-2-yl)-2-anthracenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthracenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as: 2DPABPhA), 9,10-bis(biphenyl-2-yl)-N-[4-(9H-carbazol-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-diphenyltetracene (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 (abbreviated as DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviated as p-mPhTD), 7, 14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviated as 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 (abbreviated as DCJTI), 2-{2-tert-butyl 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 (abbreviated as DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)malononitrile (abbreviated as 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 (abbreviated as: BisDCJTM), N,N'-diphenyl-N,N'- (1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviated as: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as: 3,10FrA2Nbf(IV)-02), etc. In particular, 1,6FLPAPrn, Condensed aromatic diamine compounds represented by pyrene diamine compounds such as 1,6mMemFLPAPrn and 1,6BnfAPrn-03 are preferred because they have high hole-trapping properties, high luminous efficiency, and high reliability.

[0256] In addition, 5,9-diphenyl-5,9-diaza-13b-borazinonaphtho[3,2,1-de]anthracene (abbreviated as DABNA1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-3-amine (abbreviated as DABNA2), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetrakis(4-tert-butylphenyl)-5H,9H-[1,4]benzoazaborolo[2,3,4-kl]phenathazabor-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzoazaborolo[2,3,4-kl]phenathazaborolo(abbreviation: Me-tBu4DABNA), N 7 , N 7 , N 13 , N 13 Nitrogen- and boron-containing fused heteroaromatic compounds such as 5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzoazaboro[2,3,4-kl][1,4]benzoazaboro[4',3',2':4,5][1,4]benzoazaboro[3,2-b]phenazaboro-7,13-diamine (abbreviated as ν-DABNA), 2-(4-tert-butylphenyl)benzo[5,6]indole[3,2,1-jk]benzo[b]carbazole (abbreviated as tBuPBibc), and especially compounds having a diaza-boraphtho-anthracene skeleton have a narrow emission spectrum and can obtain blue light emission with good color purity, so they can be appropriately used.

[0257] In addition to the above, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazol-9-yl]-2,5,15,18-tetra(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzazaboro[2,3,4-kl]phenathazaboro (abbreviation: BBCz-G), 9,11-bis[3,6-bis(1,1-dimethylethyl)-9H-carbazol-9-yl]-2,5,15,18-tetra(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzazaboro[2,3,4-kl]phenathazaboro (abbreviation: BBCz-Y), etc. can also be appropriately used.

[0258] When a phosphorescent substance is used as a light-emitting substance in the light-emitting layer, examples of usable materials include the following substances.

[0259] Examples include organometallic 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. compounds; 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 organometallic iridium complexes with a 1H-triazole skeleton; fac-tris[1-(2,6-diazole)iridium(III)] 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); 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 bis[2-(4',6'-difluorophenyl)pyridinium-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’Organometallic iridium complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands, such as iridium (III) acetylacetonate (abbreviated as FIr(acac)). These compounds emit blue phosphorescence and have a peak emission wavelength in the 450nm to 520nm range.

[0260] In addition, tris(4-methyl-6-phenylpyrimidinyl)iridium(III) (abbreviated as [Ir (mppm)3]), tris(4-tert-butyl-6-phenylpyrimidinyl)iridium(III) (abbreviated as: [Ir(tBuppm) 3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviated as: [Ir (mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviated as [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviated as [Ir(nbppm)2(acac)]), Organometallic iridium complexes with a pyrimidine skeleton, such as (acetylacetonate)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinate]iridium(III) (abbreviated as Ir(mpmppm)2(acac)) and (acetylacetonate)bis(4,6-diphenylpyrimidinate)iridium(III) (abbreviated as [Ir(dppm)2(acac)]); (acetylacetonate)bis(3,5-dimethyl-2-phenylpyrazinate)iridium(III) (abbreviated as [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazino)iridium(III) (abbreviated as [Ir(mppr-iPr)2(acac)]), etc., which have a pyrazine skeleton; tris(2-phenylpyridino-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]quinolinolato)iridium(III) acetylacetonate (abbreviated as [Ir(bzq)2(acac)]), tris(benzo[h]quinolinolato)iridium(III) (abbreviated as [Ir(bzq)2(acac)]), [Ir(bzq)3]), tris(2-phenylquinoline-N,C 2’ )iridium (III) (abbreviated as [Ir(pq)3]), bis(2-phenylquinoline-N, C 2’)iridium(III) acetylacetonate (abbreviated as [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridyl-κN)benzofuro[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)benzofuro[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-pyridinyl-κN2)phenyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviated as [Ir(5mppy-d3)2(mdppy-d3)]), [2-methyl-(2-pyridyl-κN)benzofuro[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(III) Organometallic iridium complexes with a pyridine skeleton, such as [Ir(ppy)2(mdppy)]; and rare earth metal complexes, such as tris(acetylacetonato)(monophenanthroline)terbium(III) (Tb(acac)3(Phen)]). These compounds primarily exhibit green phosphorescence, with a peak emission in the 500nm to 600nm wavelength range. Organometallic iridium complexes with a pyrimidine skeleton are particularly preferred due to their exceptional reliability and luminous efficiency.

[0261] In addition, organometallic iridium complexes having a pyrimidine skeleton such as (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)]), and bis[4,6-di(naphthalene-1-yl)pyrimidinyl](dipivaloylmethanone)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]); and (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazine)(dipivaloylmethane)iridium(III) (abbreviated as [Ir(tppr)2(dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxaline]iridium(III) (abbreviated as [Ir(Fdpq)2(acac)]), etc.; tris(1-phenylisoquinoline-N,C 2’ )iridium (III) (abbreviated as [Ir(piq)3]), bis(1-phenylisoquinoline-N, C 2’ )iridium(III) acetylacetonate (abbreviated as [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)-1-isoquinolyl-κN]phenyl-κC] Organometallic iridium complexes with a pyridine skeleton, such as [1,3-diphenyl-1,3-propanedione] (1,3-diphenyl-1,3-propanedione) (monophenanthroline) europium (III) (abbreviated as [Eu (DBM)3(Phen)]), tris[1-(2-thiophenoyl)-3,3,3-trifluoroacetone](monophenanthroline)europium(III) (abbreviated as: [Eu(TTA)3(Phen)]) and other rare earth metal complexes. These substances are compounds that exhibit red phosphorescence and have an emission peak in the wavelength range of 600 nm to 700 nm. Furthermore, organometallic iridium complexes having a pyrazine skeleton can produce red luminescence with good chromaticity.

[0262] Furthermore, in addition to the above-mentioned phosphorescent compounds, known phosphorescent compounds can be selected and used.

[0263] 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 used. 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) represented by the following structural formula.

[0264] [Chemical Formula 20]

[0265] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[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-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, such as 3,5-triazine (abbreviated as PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthene-9-one (abbreviated as ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridinium)phenyl]sulfone (abbreviated as DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracenes]-10'-one (abbreviated as ACRSA). These heterocyclic compounds having both a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring have high electron-transporting and hole-transporting properties and are therefore preferred. Among them, among the skeletons with π-deficient heteroaromatic rings, pyridine skeletons, diazine skeletons (pyrimidine skeletons, pyrazine skeletons, pyridazine skeletons) and triazine skeletons are stable and have good reliability, so they are preferred. In particular, the electron acceptor properties of the benzofuranopyrimidine skeleton, the benzothienopyrimidine skeleton, the benzofuranopyrazine skeleton, and the benzothienopyrazine skeleton are high and reliable, so they are preferred. In addition, among the skeletons with π-rich heteroaromatic rings, 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 the furan skeleton, a dibenzofuran skeleton is preferably used, and as the thiophene skeleton, a dibenzothiophene skeleton is preferably used. As the pyrrole skeleton, an indole skeleton, a carbazole skeleton, an indolecarbazole skeleton, a bicarbazole skeleton, and a 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton are particularly preferably used. In materials where a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded, the electron-donating properties of the π-electron-rich heteroaromatic ring and the electron-accepting properties of the π-electron-deficient heteroaromatic ring are both high, while the energy difference between the S1 and T1 levels is reduced, allowing efficient thermally activated delayed fluorescence. Note that aromatic rings bonded to electron-withdrawing groups such as cyano groups can also be used in place of the π-electron-deficient heteroaromatic ring. Furthermore, aromatic amine skeletons, phenazine skeletons, and the like can be used as π-electron-rich skeletons.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 or boranthrene, an aromatic ring or heteroaromatic ring having a nitrile or cyano group such as benzonitrile or cyanophenyl, 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 or 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.

[0266] [Chemical Formula 21]

[0267] TADF materials are materials with a small difference between the S1 and T1 energy levels and the ability to convert triplet excitation energy into singlet excitation energy through anti-intersystem crossing. Therefore, they can up-convert triplet excitation energy into singlet excitation energy (anti-intersystem crossing) using minimal thermal energy, efficiently generating singlet excited states. Furthermore, they can convert triplet excitation energy into luminescence.

[0268] 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 due to the extremely small difference between the S1 energy level and the T1 energy level.

[0269] 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. Regarding TADF materials, when the wavelength energy of an extrapolated line obtained by cutting a line at the short-wavelength tail of the fluorescence spectrum is used as the S1 level and the wavelength energy of an extrapolated line obtained by cutting a line at the short-wavelength tail of the phosphorescence spectrum is used 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.

[0270] When a TADF material is used as a light-emitting substance, the S1 energy level of the host material is preferably higher than that of the TADF material. In addition, the T1 energy level of the host material is preferably higher than that of the TADF material.

[0271] As the host material of the light-emitting layer, various carrier transport materials such as a material having an electron-transporting property and / or a material having a hole-transporting property, and the above-mentioned TADF material can be used.

[0272] As materials having hole-transporting properties, organic compounds having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton are preferably used. The π-electron-rich heteroaromatic ring is preferably 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. Specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which these rings are further fused with an aromatic ring or a heteroaromatic ring is preferred.

[0273] This organic compound having hole-transporting properties preferably has any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, it can 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 the nitrogen of the amine via an arylene group. Note that when these organic compounds having hole-transporting properties include an N,N-bis(4-biphenyl)amino group, they are preferred because they can produce light-emitting devices with long lifetimes.

[0274] 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-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), and 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine. -(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl -N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (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 compounds having a furan skeleton such as 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). Among them, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability and high hole transport properties and help to reduce the driving voltage. In addition, organic compounds listed as examples of materials having hole transport properties as the hole transport layer can also be used.

[0275] As materials having electron-transporting properties, for example, metal complexes such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviated as BeBq2), bis(2-methyl-8-hydroxyquinolinato)(4-phenylphenol)aluminum(III) (abbreviated as BAlq), bis(8-hydroxyquinolinato)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviated as ZnPBO), and bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ) are preferably used, as well as organic compounds containing a π-electron-deficient heteroaromatic ring skeleton. Examples of organic compounds containing a π-electron-deficient heteroaromatic ring include organic compounds containing a heteroaromatic ring having an oxazole skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, organic compounds containing a heteroaromatic ring having a diazine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton.

[0276] 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 and are therefore 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 contribute to reducing the driving voltage. In addition, benzofuranopyrimidine skeletons, benzothienopyrimidine skeletons, benzofuranopyrazine skeletons, and benzothienopyrazine skeletons have high electron acceptor properties and high reliability, so they are preferred.

[0277] Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include: 2- (4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3- (4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), Organic compounds having an azole skeleton, such as 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviated as OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviated as CO11), 2,2',2"-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviated as TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as mDBTBIm-II), and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviated as BzOs); 3,5-bis[3- (9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), 2,9-di(naphth-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(2-triphenylene)phenyl]-1,10-phenanthroline (abbreviation: mTpPPhen), 2-phenyl-9-(2-triphenylene)-1, Organic compounds containing a heteroaromatic ring having a pyridine skeleton, such as 10-phenanthroline (abbreviation: Ph-TpPhen), 2-[4-(9-phenanthrenyl)-1-naphthyl]-1,10-phenanthroline (abbreviation: PnNPhen), and 2-[4-(2-triphenylene)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen); 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl- 3-phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-I I), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviated as: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviated as: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (Abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (Abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (Abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-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)(biphenyl-3-yl)]naphtho[1',2':4,5]furo[3,2-d]pyrimidine (abbreviated as: 8mDBtBPNfpm), 8-[(2,2'-binaphthyl)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[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-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviated as: 6mBP-4Cz2PPm), 2,6-bis(4-naphthyl-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviated as: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviated as: 6B organic compounds having a diazine skeleton, such as 2-(4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl)-7H-dibenzo[c,g]carbazole (abbreviated as PC-cgDBCzQz); 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviated as BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as mBnfBPTzn), 2-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviated as PC-cgDBCzQz); ...4Cz2PPm); 2-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviated as PC-cgDBCzQz); 2-[4 -{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-carbazol-3-yl)-9H-carbazol-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 (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 (abbreviated as: 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-phenyl-indolo[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), Organic compounds containing heteroaromatic rings having a triazine skeleton, such as 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), etc. In addition, organic compounds containing heteroaromatic rings having a diazine skeleton, organic compounds containing heteroaromatic rings having a pyridine skeleton, or organic compounds containing heteroaromatic rings having a triazine skeleton have high reliability and are therefore 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 help to reduce the driving voltage.

[0278] TADF materials that can be used as host materials can be the same as those listed above. When using a TADF material as a host material, the triplet excitation energy generated by the TADF material is converted to singlet excitation energy via reverse intersystem crossing and further transferred to the luminescent material, thereby improving the luminous efficiency of the light-emitting device. In this case, the TADF material acts as an energy donor, and the luminescent material acts as an energy acceptor.

[0279] This is particularly effective when the luminescent material is a fluorescent material. Furthermore, in order to achieve high luminous efficiency, the S1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent material. Furthermore, the T1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent material. Therefore, the T1 energy level of the TADF material is preferably higher than the T1 energy level of the fluorescent material.

[0280] Furthermore, it is preferable to use a TADF material that emits light at a wavelength that overlaps with the lowest-energy absorption band of the fluorescent substance. This allows for smooth transfer of excitation energy from the TADF material to the fluorescent substance, resulting in efficient emission.

[0281] In order to efficiently generate singlet excitation energy from triplet excitation energy by 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, fluorescent material preferably has a protecting group around the luminophore (the skeleton that becomes the cause of luminescence) possessed by fluorescent material. As the protecting group, it is preferably a substituent without a π bond, preferably a saturated hydrocarbon, specifically, an alkyl group having 3 or more and 10 or less carbon atoms, a cycloalkyl group having 3 or more and 10 or less carbon atoms, a trialkylsilyl group having 3 or more and 10 or less carbon atoms, more preferably having multiple protecting 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 TADF material and fluorescent material can be kept away from each other. Here, luminophore refers to the atomic group (skeleton) that becomes the cause of luminescence in 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 the luminophore 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, skeleton, triphenylene skeleton, tetracene skeleton, pyrene skeleton, perylene skeleton, coumarin skeleton, quinacridone skeleton, naphthobisbenzofuran skeleton, etc. In particular, the skeletons having naphthalene skeleton, anthracene skeleton, fluorene skeleton, 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.

[0282] When a fluorescent light-emitting substance is used as a light-emitting substance, 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 light-emitting substance, a light-emitting layer with 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, when 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 higher than when the carbazole skeleton is included, and holes are easily injected, so it is more preferred. In particular, when the host material has a dibenzocarbazole skeleton, its HOMO energy level is about 0.1eV higher than when the carbazole skeleton is included, and not only holes are easily injected, but also hole transport and heat resistance are improved, so it is preferred. Therefore, it is further preferred that the substance used as the main material is a substance having a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). Note that from the perspective of the above-mentioned hole injection / transport properties, a benzofluorene skeleton or a dibenzofluorene skeleton can also be used instead of the carbazole skeleton. As examples of such substances, 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as: PCzPA), 3-[4- (1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-[4-(9-phenyl-9H-fluoren-9-yl)-biphenyl-4'-yl]-anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-1 0-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,βADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracen-9-yl)-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-anthracen-9-yl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), etc. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred because they exhibit very good properties.

[0283] Alternatively, the host material can be a mixture of multiple substances. When using a mixed host material, it is preferable to mix a material having electron-transporting properties with a material having hole-transporting properties. By mixing materials having electron-transporting properties with materials having hole-transporting properties, the transport properties of the light-emitting layer 113 can be adjusted more easily, and the recombination area can be more easily controlled. The weight ratio of the hole-transporting material to the electron-transporting material can also be 1:19 to 19:1.

[0284] Note that a phosphorescent substance may be used as part of the mixed material. When a fluorescent substance is used as the luminescent substance, the phosphorescent substance can function as an energy donor for supplying excitation energy to the fluorescent substance.

[0285] Alternatively, these mixed materials can be used to form an exciplex. Selecting mixed materials to form an exciplex that emits light at a wavelength overlapping with the absorption band on the lowest energy side of the luminescent substance is preferred because it allows for smooth energy transfer and efficient luminescence. Furthermore, this structure is preferred because it reduces the driving voltage.

[0286] 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 reverse intersystem crossing.

[0287] Regarding the combination of materials that efficiently form exciplexes, the HOMO energy level of the material having hole transport properties is preferably greater 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 greater 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 determined from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV).

[0288] Note that the formation of an exciplex can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, the emission spectra of an electron-transporting material, and the emission spectra of a mixed film formed by mixing these materials. If the emission spectrum of the mixed film shifts toward the longer wavelength side compared to the emission spectra of each material (or has a new peak on the longer wavelength side), it indicates the formation of an exciplex. Alternatively, by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a mixed film formed by mixing these materials, if a difference in transient response is observed, such as a longer-life component or a larger ratio of delayed components in the transient PL lifetime of the mixed film compared to the transient PL lifetime of each material, it indicates the formation of an exciplex. Furthermore, the above-mentioned transient PL can be referred to as transient electroluminescence (EL). In other words, by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a mixed film of these materials and observing the difference in transient response, the formation of an exciplex can be confirmed.

[0289] The electron transport layer 114 is a layer containing a substance 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, preferably 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 also be used. As the above-mentioned organic compound, an organic compound containing a π-electron-deficient heteroaromatic ring is preferably used. As an organic compound containing a π-electron-deficient heteroaromatic ring, for example, 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 are preferably used. One or more of the organic compounds are preferably used.

[0290] As an organic compound with electron transport properties that can be used for the above-mentioned electron transport layer 114, the organic compound with electron transport properties in the above-mentioned light-emitting layer 113 and the organic compound exemplified as the second organic compound that can be used for the electron injection layer 115 in embodiment 1 can be used in the same manner. Among them, organic compounds comprising heteroaromatic rings having a diazine skeleton, organic compounds comprising heteroaromatic rings having a pyridine skeleton, and organic compounds comprising heteroaromatic rings having a triazine skeleton have good reliability, so they are preferred. In particular, organic compounds comprising heteroaromatic rings having a diazine (pyrimidine or pyrazine) skeleton and organic compounds comprising heteroaromatic rings having a triazine skeleton have high electron transport properties, which help to reduce the driving voltage. In particular, organic compounds having a phenanthroline skeleton such as mTpPPhen, PnNPhen and mPPhen2P are preferred, and organic compounds having a phenanthroline dimer structure such as mPPhen2P have excellent stability, so they are more preferred.

[0291] Furthermore, the electron transport layer preferably comprises an acid having an acid dissociation constant pK a An organic compound with an electron-transporting property of less than 4.

[0292] Note that the electron-transport layer 114 may also have a stacked-layer structure. Furthermore, when the electron-transport layer 114 has a stacked-layer structure, the layer in contact with the light-emitting layer 113 may also function as a hole-blocking layer. When the electron-transport layer in contact with the light-emitting layer functions as a hole-blocking layer, a material having a HOMO level at least 0.5 eV lower than that of the material included in the light-emitting layer is preferably used.

[0293] An electron injection layer 115 is formed between the electron transport layer 114 and the second electrode 102. The structure of the electron injection layer 115 has been described in detail in Embodiment 1, and thus repeated description will be omitted.

[0294] The second electrode 102 is preferably formed in contact with the electron injection layer 115. The structure of the second electrode has been described in detail in Embodiment 1, and thus repeated description will be omitted.

[0295] 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.

[0296] The conductive material constituting the second electrode 102 can be deposited by a dry method such as vacuum evaporation or sputtering, an inkjet method, or a spin coating method. Alternatively, the conductive material can be formed by a wet method such as a sol-gel method or a wet method using a metal paste.

[0297] In addition, in top-emitting devices, light extraction efficiency can be improved by vapor-depositing an organic compound onto the second electrode to form a capping layer. The capping layer can be a single layer or a stacked layer. In the case of a stacked layer, light extraction efficiency can be further improved by using organic compounds with different refractive indices.

[0298] The organic compound layer 103 can be formed using various methods, whether dry or wet, such as vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, or spin coating.

[0299] In addition, the electrodes or layers described above may also be formed by using different deposition methods.

[0300] When forming the second electrode 102, a deposition method such as sputtering which causes great damage to the substrate is used. Figure 1B As shown, a P-type layer 117 may also be provided to protect the electron injection layer 115. The P-type layer 117 can be formed using the composite material described above as a material that can be used for the hole injection layer 111. Since transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide are stronger than organic compounds, using them as a substance having acceptor properties for the P-type layer can prevent damage during formation of the second electrode 102, making them preferred.

[0301] Note that although not shown in the figure, an electron relay layer can also be provided between the electron injection layer 115 and the P-type layer 117. The electron relay layer contains at least a substance having an electron-transporting property, and is capable of preventing the interaction between the electron injection layer 115 and the P-type layer 117 and smoothly transferring electrons. The LUMO energy level of the substance having an electron-transporting property contained in the electron relay layer is preferably set between the LUMO energy level of the acceptor substance in the P-type layer 117 and the LUMO energy level of the substance contained in the layer in the electron transport layer 114 that contacts the electron injection layer 115. The specific value of the LUMO energy level of the substance having an electron-transporting property in the electron relay layer is preferably greater than -5.0 eV, and more preferably greater than -5.0 eV and less than -3.0 eV. In addition, as the substance having an electron-transporting property in the electron relay layer, it is preferred to use a phthalocyanine material or a metal complex having a metal-oxygen bond and an aromatic ligand. As the substance having electron transport properties that can be used in the electron relay layer, specifically, perylenetetracarboxylic acid derivatives such as 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), (C 60 -I h )[5,6]fullerene (abbreviated as: C 60 )、(C 70 -D 5h )[5,6]fullerene (abbreviated as: C 70 ). In addition, a compound having a heterocyclic ring and a heterocyclic ring skeleton 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 (CuPc), zinc phthalocyanine (ZnPc), cobalt phthalocyanine (CoPc), iron phthalocyanine (FePc), tin phthalocyanine (SnPc), tin phthalocyanine oxide (SnOPc), titanium phthalocyanine oxide (TiOPc), and vanadium phthalocyanine oxide (VOPc), and their derivatives can also be used. In addition, 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 particularly preferably used.

[0302] Furthermore, the thickness of the electron-relay layer is preferably from 1 nm to 10 nm, and more preferably from 2 nm to 5 nm.

[0303] Next, refer to Figure 1CA light emitting device having a structure in which a plurality of light emitting units are stacked (also referred to as a stacked device or a tandem device) is described. This light emitting device is a light emitting device having a plurality of light emitting units between a first electrode 101 and a cathode. One light emitting unit has Figure 1A The organic compound layer 103 shown in FIG. 1 has substantially the same structure. In other words, it can be said that Figure 1C The light emitting device shown is a light emitting device having a plurality of light emitting units. Figure 1A The light-emitting device shown is a light-emitting device having one light-emitting unit.

[0304] exist Figure 1C In the embodiment, a first light emitting unit 511 and a second light emitting unit 512 are stacked between the first electrode 501 and the second electrode 502, and an intermediate layer 513 is provided between the first light emitting unit 511 and the second light emitting unit 512. The first electrode 501 and the second electrode 502 are equivalent to Figure 1A The first electrode 101 and the second electrode 102 in the embodiment of the present invention can be applied to Figure 1A The same materials as described above. In addition, the structures of the layers of the first light-emitting unit 511 and the second light-emitting unit 512 can be the same or different. In addition, the materials constituting the layers of the first light-emitting unit 511 and the second light-emitting unit 512 can be the same or different.

[0305] The intermediate layer 513 has a function of injecting electrons into one light-emitting unit and injecting holes into the other light-emitting unit when a voltage is applied to the first electrode 501 and the second electrode 502. Figure 1C When a voltage is applied so that the potential of the first electrode 101 is higher than that of the cathode, the intermediate layer 513 can inject electrons into the first light-emitting unit 511 and holes into the second light-emitting unit 512 .

[0306] The intermediate layer 513 includes a charge generation layer. Furthermore, the charge generation layer includes at least a P-type layer 117. The P-type layer 117 is preferably formed using the composite material that constitutes the hole injection layer 111. Alternatively, the P-type layer 117 may be formed by stacking a film containing an acceptor material and a film containing a hole transport material, as described above as materials constituting the composite material. By applying a potential to the P-type layer 117, electrons and holes are injected into the electron transport layer 114 and the cathode, respectively, causing the light-emitting device to operate.

[0307] In addition, the intermediate layer 513 preferably includes one or both of an electron relay layer 118 and an N-type layer 119 in addition to the P-type layer 117 .

[0308] The electron relay layer 118 has Figure 1B The structure is the same as that of the electron relay layer mentioned in the description, so repeated description is omitted.

[0309] The N-type layer 119 can use substances with high electron injection properties such as alkali metals, alkaline earth metals, rare earth metals and compounds of these substances (alkali metal compounds (including oxides such as lithium oxide, halides, carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates) or rare earth metal compounds (including oxides, halides, carbonates)).

[0310] In addition, when the N-type layer 119 contains a substance having an electron-transporting property and a donor substance, as the donor substance, in addition to alkali metals, alkaline earth metals, rare earth metals, and compounds of these substances (alkali metal compounds (including oxides such as lithium oxide, halides, carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates), or rare earth metal compounds (including oxides, halides, carbonates)), organic compounds such as tetrathianaphthacene (abbreviated as: TTN), nickelocene, and decamethylnickelocene can also be used. In addition, as the substance having an electron-transporting property, the same material as the material for the electron-transporting layer 114 described above can be used.

[0311] Alternatively, a layer described in Embodiment 1 as an electron injection layer may be provided at the same position as N-type layer 119, in place of N-type layer 119. This layer may include a metal compound and an organic compound containing a phenanthroline ring having an electron-donating group. This structure can also be used to manufacture a tandem light-emitting device with excellent characteristics.

[0312] When the surface of the light-emitting unit on the first electrode 101 side contacts the intermediate layer 513, the charge generation layer of the intermediate layer 513 can also function as the hole injection layer of the light-emitting unit, so the light-emitting unit does not need to be provided with a hole injection layer. When the surface of the light-emitting unit on the cathode side contacts the intermediate layer 513, the intermediate layer 513 can also function as the electron injection layer of the light-emitting unit, so the light-emitting unit does not need to be provided with an electron injection layer.

[0313] Although Figure 1C While a light-emitting device having two light-emitting units is described above, light-emitting devices having three or more stacked light-emitting units can also be applied. As in the light-emitting device of this embodiment, by separating and arranging multiple light-emitting units between a pair of electrodes using an intermediate layer 513, a device can be realized that can achieve high-brightness emission while maintaining a low current density and has a long life. Furthermore, a light-emitting device capable of low-voltage operation and low power consumption can be realized.

[0314] Furthermore, by making each light-emitting unit emit a different color, the entire light-emitting device can emit light of a desired color. For example, by emitting red and green light from the first light-emitting unit and blue light from the second light-emitting unit in a light-emitting device having two light-emitting units, a light-emitting device can be obtained that emits white light throughout the entire device.

[0315] In addition, the above-mentioned organic compound layer 103, the first light-emitting unit 511, the second light-emitting unit 512, the intermediate layer 513 and other layers and electrodes can be formed by, for example, evaporation method (including vacuum evaporation method), droplet injection method (also known as inkjet method), coating method, gravure printing method and the like. In addition, it may also include low molecular weight materials, medium molecular weight materials (including oligomers, dendrimers) or high molecular weight materials.

[0316] Figure 4A This diagram shows two adjacent light-emitting devices (a light-emitting device 130 a and a light-emitting device 130 b ) included in a display device according to one embodiment of the present invention.

[0317] The light-emitting device 130a includes an organic compound layer 103a between a first electrode 101a on an insulating layer 175 and a second electrode 102a opposite the first electrode 101a. The organic compound layer 103a includes an electron injection layer 115a. Although the organic compound layer 103a is shown as including a hole injection layer 111a, a hole transport layer 112a, a light-emitting layer 113a, an electron transport layer 114a, and an electron injection layer 115a, the organic compound layer 103a may have a stacked structure different from the above structure.

[0318] The light-emitting device 130b includes an organic compound layer 103b between a first electrode 101b on an insulating layer 175 and a second electrode 102b opposite the first electrode 101b. The organic compound layer 103b includes an electron injection layer 115b. Although the organic compound layer 103b is shown as including a hole injection layer 111b, a hole transport layer 112b, a light-emitting layer 113b, an electron transport layer 114b, and an electron injection layer 115b, the organic compound layer 103b may have a stacked structure different from the above structure.

[0319] The structures of the electron injection layer 115a and the second electrode 102a in the light-emitting device 130a and the electron injection layer 115b and the second electrode 102b in the light-emitting device 130b preferably adopt the structures described in Embodiment 1.

[0320] The organic compound layers 103a and 103b, as well as the second electrodes 102a and 102b, are processed by photolithography after forming the films that will become the second electrodes 102a and 102b, respectively. Therefore, they are independent of each other. A light-emitting device according to one embodiment of the present invention can achieve excellent characteristics even when photolithography is performed after forming the films that will become the second electrodes 102a and 102b.

[0321] Furthermore, the end portion (outline) of the second electrode 102a and the end portion (outline) of the organic compound layer 103a are processed by photolithography so as to be substantially aligned in a direction perpendicular to the substrate. Furthermore, the end portion (outline) of the second electrode 102b and the end portion (outline) of the organic compound layer 103b are processed by photolithography so as to be substantially aligned in a direction perpendicular to the substrate.

[0322] In addition, due to photolithography, a gap d exists between the organic compound layer 103a and the organic compound layer 103d. Furthermore, by processing the organic compound layers using photolithography, the distance between the first electrode 101c and the first electrode 101d can be reduced to a value not less than 0.5 μm and not more than 5 μm.

[0323] Figure 4B This is a diagram of two adjacent tandem light-emitting elements (light-emitting device 130c and light-emitting device 130d) manufactured by photolithography.

[0324] The light emitting device 130c includes an organic compound layer 103c between a first electrode 101c and a second electrode 102c on an insulating layer 175. The organic compound layer 103c has a structure in which a first light emitting unit 501c and a second light emitting unit 502c are stacked with an intermediate layer 116c interposed therebetween. Figure 4B An example of stacking two light emitting units is shown, but three or more light emitting units may be stacked. Figure 4B In the embodiment, 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 P-type layer 117c, an electron relay layer 118c, and an N-type layer 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 115c. The presence or absence of the electron relay layer 118c is irrelevant.

[0325] The light emitting device 130d includes an organic compound layer 103d between a first electrode 101d and a second electrode 102d 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 with an intermediate layer 116d interposed therebetween. Figure 4B An example of stacking two light emitting units is shown, but three or more light emitting units may be stacked. Figure 4B In the embodiment, 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 P-type layer 117d, an electron relay layer 118d, and an N-type layer 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 115d. The presence or absence of the electron relay layer 118d is irrelevant.

[0326] In the light-emitting devices 130c and 130d, the electron injection layers 115c and 115d, and the second electrodes 102c and 102d preferably have the structures described in Embodiment 1.

[0327] Furthermore, the organic compound layer 103c and the organic compound layer 103d are processed by photolithography after forming the films that will become the second electrodes 102c and 102d, respectively, and are therefore independent of each other. A light-emitting device according to one embodiment of the present invention can achieve excellent characteristics even when photolithography is performed after forming the films that will become the second electrodes 102c and 102d.

[0328] The second electrode 102c and the organic compound layer 103c are processed by photolithography and are therefore substantially aligned in a direction perpendicular to the substrate. The second electrode 102d and the organic compound layer 103d are processed by photolithography and are therefore substantially aligned in a direction perpendicular to the substrate.

[0329] In addition, due to photolithography, a gap d exists between the organic compound layer 103c and the organic compound layer 103d. Furthermore, by processing the organic compound layers using photolithography, the distance between the first electrode 101c and the first electrode 101d can be reduced to a value between 0.5 μm and 5 μm, which is smaller than that during masked evaporation.

[0330] Furthermore, since the second electrodes 102a and 102b are independent of each other, or the second electrodes 102c and 102d are independent of each other, an auxiliary electrode 105 is preferably formed to apply a voltage to the plurality of second electrodes included in the light-emitting device. The auxiliary electrode 105 is preferably formed after forming an insulating layer 106 between the second electrodes 102a and 102b, or between the light-emitting devices 130c and 130d, to prevent short circuits with the organic compound layer or the first electrode. The insulating layer 106 is preferably formed using an organic insulating material. The auxiliary electrode 105 can use a material that can be used for the second electrode.

[0331] A light-emitting device according to one embodiment of the present invention utilizes photolithography to process an organic compound layer with sufficient precision, thereby enabling the manufacture of high-definition display devices. Furthermore, since the photolithography process can be performed on an electron injection layer remote from the light-emitting layer without contamination by alkali metals, a light-emitting device with excellent characteristics can be realized. As described above, a light-emitting device according to one embodiment of the present invention having the above-described structure can realize a high-definition display device and a light-emitting device with excellent characteristics.

[0332] Furthermore, because the second electrode and organic compound layer of the light-emitting device according to one embodiment of the present invention are processed simultaneously using photolithography after the second electrode is formed, the contours of the layers included in the organic compound layer are substantially aligned when viewed from a direction approximately perpendicular to the surface of the insulating layer on which the first electrode is formed. Furthermore, the end of the cross section of the second electrode and the end of the cross section of the first layer are substantially aligned in a direction approximately perpendicular to the surface of the insulating layer on which the first electrode is formed. In this specification, "substantially aligned" means that the difference between the contours A of layer A and B of layer B in contact with each other is within 5% of the width of the organic compound layer on a line perpendicular to the contours of the comparison portion. Furthermore, "substantially perpendicular" refers to an angle of 85° to 95°.

[0333] The structure of this embodiment can be used in combination with other structures as appropriate.

[0334] Implementation 3 In this embodiment, an embodiment in which a light-emitting device according to one embodiment of the present invention is used as a display element of a display device is described.

[0335] like Figure 5A and Figure 5B As shown, a plurality of light emitting devices 130 are formed on the insulating layer 175 and constitute a display device.

[0336] 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.

[0337] In this specification, for example, when describing common features 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 common features among other components distinguished by letters, the letters may be omitted.

[0338] Sub-pixel 110R emits red light, sub-pixel 110G emits green light, and sub-pixel 110B emits blue light. Thus, a full-color image can be displayed on the pixel portion 177. In this 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 can also be used. In addition, the number of sub-pixels is not limited to three, and four or more can also be used. As four sub-pixels, for example, there can be cited: 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.

[0339] 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.

[0340] exist Figure 5A 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 also be arranged in the Y direction, and sub-pixels of the same color may be arranged in the X direction.

[0341] In addition, the layout of the sub-pixels is not limited thereto, and various arrangements such as stripe arrangement, S-stripe arrangement, matrix arrangement, Delta arrangement, Bayer arrangement, and Pentile arrangement may be adopted. Figures 23A to 23G An example of the layout of sub-pixels is shown.

[0342] Figure 23A The pixels 178 are shown arranged in an S-stripe pattern. Figure 23A The pixel 178 shown is composed of three sub-pixels: a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0343] Figure 23B Pixel 178 shown includes sub-pixel 110R having a top shape that is approximately trapezoidal or triangular with rounded corners, sub-pixel 110G having a top shape that is approximately trapezoidal or triangular with rounded corners, and sub-pixel 110B having a top shape that is approximately quadrilateral or hexagonal with rounded corners. Furthermore, sub-pixel 110R has a larger light-emitting area than sub-pixel 110G. Thus, the shape and size of each sub-pixel can be determined independently. For example, a sub-pixel that includes a highly reliable light-emitting device can be smaller in size.

[0344] Figure 23C The pixels 124a and 124b shown are arranged in a Pentile arrangement. Figure 23C In the illustrated example, the pixel 124 a including the sub-pixel 110R and the sub-pixel 110G and the pixel 124 b including the sub-pixel 110G and the sub-pixel 110B are alternately arranged.

[0345] Figures 23D to 23F Pixels 124a and 124b are shown in a delta arrangement. Pixel 124a includes two subpixels (subpixel 110R and subpixel 110G) in the upper row (first row) and one subpixel (subpixel 110B) in the lower row (second row). Pixel 124b includes one subpixel (subpixel 110B) in the upper row (first row) and two subpixels (subpixel 110R and subpixel 110G) in the lower row (second row).

[0346] Figure 23D An example is shown in which each sub-pixel has a top surface shape that is approximately quadrangular with rounded corners. Figure 23E An example is shown in which each sub-pixel has a circular top surface shape. Figure 23F An example is shown in which each sub-pixel has a top surface shape that is approximately hexagonal with rounded corners.

[0347] exist Figure 23F In the example, each subpixel is arranged inside a tightly packed hexagonal area. Each subpixel is arranged so that, when focusing on one subpixel, it is surrounded by six subpixels. Furthermore, subpixels that emit the same color light are arranged so that they are not adjacent to each other. For example, when focusing on subpixel 110R, the subpixels are arranged so that three subpixels 110G and three subpixels 110B are arranged alternately around subpixel 110R.

[0348] Figure 23G Specifically, in a plan view, the top sides of two subpixels arranged in the row direction (for example, subpixel 110R and subpixel 110G or subpixel 110G and subpixel 110B) are offset from each other.

[0349] exist Figures 23A to 23G In the illustrated pixels, for example, sub-pixel 110R is preferably configured as sub-pixel R emitting red light, sub-pixel 110G is preferably configured as sub-pixel G emitting green light, and sub-pixel 110B is preferably configured as sub-pixel B emitting blue light. Note that the sub-pixel structure is not limited to this, and the colors emitted by the sub-pixels and their arrangement order can be appropriately determined. For example, sub-pixel 110G can be configured as sub-pixel R emitting red light, and sub-pixel 110R can be configured as sub-pixel G emitting green light.

[0350] Note that when using Figure 5A and Figure 23G In the case of the so-called stripe configuration shown, the second electrodes 102 of light-emitting devices emitting the same color can be formed continuously. In this case, even if photolithography is performed after the second electrodes 102 are formed, a voltage can be applied to each light-emitting device without the need for the auxiliary electrode 105. If the second electrodes 102 of each light-emitting device are independent of each other after photolithography, it is preferable to form the auxiliary electrode 105.

[0351] A 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. The connection portion 140 is provided with a conductive layer 151C.

[0352] exist Figure 5A In the example shown, the region 141 and the connection portion 140 are located on the right side of the pixel portion 177. However, there is no particular limitation on the positions of the region 141 and the connection portion 140. Alternatively, there may be one or more regions 141 and the connection portion 140.

[0353] Figure 5B It is along Figure 5A An example of a cross-sectional view along the dotted line A1-A2 in FIG. Figure 5A As shown, the display device includes an insulating layer 171, a conductive layer 172 on insulating layer 171, an insulating layer 173 on insulating layer 171 and on conductive layer 172, an insulating layer 174 on insulating layer 173, and an insulating layer 175 on insulating layer 174. Insulating layer 171 is provided on a substrate (not shown). Insulating layer 175, insulating layer 174, and insulating layer 173 are provided with openings that reach conductive layer 172, and plugs 176 are provided so as to fit into these openings.

[0354] In pixel portion 177, light-emitting devices 130 are provided on insulating layer 175 and plug 176. Furthermore, protective layer 131 is provided to cover light-emitting devices 130. Substrate 120 is bonded to protective layer 131 via resin layer 122. Furthermore, an inorganic insulating layer 125 and an insulating layer 127 on inorganic insulating layer 125 are preferably provided between adjacent light-emitting devices 130.

[0355] Acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin, or precursors of these resins can be used as the insulating layer 127. Alternatively, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used as the organic resin layer 180.

[0356] Alternatively, a photosensitive resin can be used as the insulating layer 127. A photoresist can also be used as the photosensitive resin. A positive-type material or a negative-type material can be used as the photosensitive resin.

[0357] The insulating layer 127 may also contain a material that absorbs visible light. For example, the insulating layer 127 itself may be formed of a material that absorbs visible light, or the insulating layer 127 may contain a pigment that absorbs visible light. For example, the insulating layer 127 may contain a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light, or a resin that contains carbon black as a pigment and is used as a black matrix.

[0358] Figure 5B Although cross-sections of the inorganic insulating layers 125 and the insulating layers 127 are shown, the inorganic insulating layers 125 and 127 are preferably formed as a continuous layer when the display device is viewed from above. In other words, the inorganic insulating layers 125 and 127 are preferably insulating layers having openings above the first electrodes.

[0359] exist Figure 5B 130R, 130G, and 130B are shown as light-emitting devices 130. Light-emitting devices 130R, 130G, and 130B emit different colors. For example, light-emitting device 130R may emit red light, light-emitting device 130G may emit green light, and light-emitting device 130B may emit blue light. Light-emitting devices 130R, 130G, and 130B may also emit other visible light or infrared light.

[0360] The display device according to 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 according to one embodiment of the present invention may have a bottom emission structure.

[0361] The light-emitting device 130R has the structure described in Embodiments 1 and 2. The light-emitting device 130R includes a first electrode 101R (pixel electrode) composed of a conductive layer 151R and a conductive layer 152R, an organic compound layer 103R on the first electrode 101R, and a second electrode 102 on the organic compound layer 103R. The electron injection layer, which is the outermost layer of the organic compound layer 103R, and the second electrode 102R have the structures described in Embodiments 1 and 2. This structure can suppress damage to the light-emitting layer or active layer during the photolithography process, allowing the light-emitting device 130R to have excellent film quality and electrical characteristics.

[0362] The light-emitting device 130G has the structure described in Embodiments 1 and 2. The light-emitting device 130G includes a first electrode 101G (pixel electrode) composed of a conductive layer 151G and a conductive layer 152G, an organic compound layer 103G on the first electrode 101G, and a second electrode 102 on the organic compound layer 103G. The electron injection layer, which is the outermost layer of the organic compound layer 103G, and the second electrode 102G have the structures described in Embodiments 1 and 2. This structure can suppress damage to the light-emitting layer or active layer during the photolithography process, allowing the light-emitting device 130G to have excellent film quality and electrical characteristics.

[0363] The light-emitting device 130B has the structure described in Embodiments 1 and 2. It includes a first electrode 101B (pixel electrode) composed of a conductive layer 151B and a conductive layer 152B, an organic compound layer 103B on the first electrode 101B, and a second electrode 102B on the organic compound layer 103B. The electron injection layer, which is the outermost layer of the organic compound layer 103B, and the second electrode 102B have the structures described in Embodiments 1 and 2. This structure can suppress damage to the light-emitting layer or active layer during the photolithography process, resulting in a light-emitting device 130B with excellent film quality and electrical characteristics.

[0364] The organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are island-shaped layers that are independent for each light-emitting device or for each emission color. Note that the organic compound layers 103R, 103G, and 103B preferably do not overlap. By providing the organic compound layer 103 in an island shape for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in high-definition display devices. This prevents crosstalk and enables a display device with extremely high contrast. In particular, a display device with high current efficiency at low brightness can be realized.

[0365] The second electrodes 102R, 102G, and 102B are each formed independently in an island shape for each light-emitting device or for each column emitting the same light-emitting color. Note that the second electrodes 102R, 102G, and 102B preferably do not overlap with each other.

[0366] Preferably, the auxiliary electrode 105 is formed after forming the insulating layer 127 on the second electrode 102 so as to cover the side surfaces of the light-emitting device 130. This facilitates the supply of voltage to the second electrode 102. The auxiliary electrode 105 can be made of, for example, a metal material. Specifically, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and magnesium (Mg), as well as alloys of these metals, can be used.

[0367] The auxiliary electrode 105 may also be made of an oxide containing one or more selected from the group consisting of indium, tin, zinc, gallium, titanium, aluminum, and silicon. For example, preferably, a conductive oxide containing one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon is used. Note that when the light-emitting device 130 is a top-emitting light-emitting device, a light-transmitting conductive metal oxide is preferably used as the auxiliary electrode 105.

[0368] The island-shaped organic compound layer 103 is formed by forming the second electrode after depositing the organic compound film, and then processing the organic compound film and the second electrode 102 using photolithography. Since the electron injection layer and the second electrode of the light-emitting device according to one embodiment of the present invention have the structure described in Embodiment 1, even if photolithography is used after forming the second electrode 102, a light-emitting device with excellent characteristics can be obtained, with a suppressed increase in driving voltage. Furthermore, by performing photolithography processing after forming the second electrode 102, an inexpensive and highly reliable light-emitting device can be obtained.

[0369] 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 5B In the example shown, the first electrode 101 of the light-emitting device 130 has a stacked structure of a conductive layer 151 (conductive layer 151R, conductive layer 151G, conductive layer 151B) arranged on one side of the insulating layer 171 and a conductive layer 152 (conductive layer 151R, conductive layer 151G, conductive layer 151B) arranged on one side of the organic compound layer.

[0370] For example, a metal material can be used as the conductive layer 151. Specifically, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), and alloys obtained by appropriately combining these metals can be used.

[0371] The conductive layer 152 can be made of an oxide containing one or more selected from the group consisting of indium, tin, zinc, gallium, titanium, aluminum, and silicon. For example, preferably used are conductive oxides containing one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. Indium tin oxide containing silicon has a particularly large work function, for example, 4.0 eV or greater, and is therefore suitable for use as the conductive layer 152.

[0372] Conductive layer 151 and conductive layer 152 may each have a stacked-layer structure including a plurality of layers of different materials. In this case, conductive layer 151 may include a layer using a material that can be used for conductive layer 152, such as a conductive oxide, and conductive layer 152 may include a layer using a material that can be used for conductive layer 151, such as a metal material. For example, when conductive layer 151 has a stacked-layer structure with two or more layers, the layer in contact with conductive layer 152 may be a layer using a material that can be used for conductive layer 152.

[0373] Figure 5B The ends of the conductive layer 151 in the embodiment have a tapered shape. Specifically, the ends of the conductive layer 151 preferably have a tapered shape with a taper angle of less than 90°. In this case, the conductive layer 152 provided along the side surfaces of the conductive layer 151 also has a tapered shape. The tapered ends of the conductive layer 152 can improve coverage with the organic compound layer 103 provided along the side surfaces of the conductive layer 152.

[0374] In addition, the ends of the conductive layer 151 and the conductive layer 152 do not need to have a tapered shape. In other words, it may be substantially vertical. In addition, the end of the organic compound layer 103 is preferably located inside the first electrode 101. In this case, leakage current through the organic compound layer 103 can be reduced, thereby achieving a display device with low driving voltage and excellent display performance.

[0375] In the display device of one embodiment of the present invention, the light-emitting device 130 has the structure described in Embodiment 1 or 2, whereby a light-emitting device with high reliability can be realized.

[0376] Next, refer to Figures 6A to 6E to Figure 11A and Figure 11B Description Figure 5A An example of a method for manufacturing a display device having the structure shown.

[0377] [Manufacturing method example 1] Thin films (insulating films, semiconductor films, conductive films, etc.) that constitute display devices can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), and atomic layer deposition (ALD).

[0378] 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, roller coating, curtain coating or doctor knife coating.

[0379] Furthermore, when processing thin films constituting the display device, for example, photolithography can be used.

[0380] In photolithography, as light used for exposure, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm), or a mixture of these can be used. Alternatively, ultraviolet light, KrF laser, or ArF laser can be used. Furthermore, exposure can be performed using liquid immersion technology. Furthermore, as light used for exposure, extreme ultraviolet (EUV) light or X-rays can be used. Furthermore, an electron beam can be used instead of light used for exposure.

[0381] For etching of the thin film, dry etching, wet etching, sand blasting, or the like can be used.

[0382] First, if Figure 6A As shown, an insulating layer 171 is formed on a substrate (not shown). Next, conductive layers 172 and 179 are formed on insulating layer 171, and insulating layer 173 is formed on insulating layer 171 to cover conductive layers 172 and 179. Next, insulating layer 174 is formed on insulating layer 173, and insulating layer 175 is formed on insulating layer 174.

[0383] As the substrate, a substrate having heat resistance at least sufficient to withstand the subsequent heat treatment can be used. Examples include glass substrates, quartz substrates, sapphire substrates, ceramic substrates, organic resin substrates, or semiconductor substrates such as single crystal or polycrystalline semiconductor substrates made of silicon or silicon carbide, compound semiconductor substrates such as silicon germanium, and SOI substrates.

[0384] Then, if Figure 6A As shown in FIG. 1 , openings reaching the conductive layer 172 are formed in the insulating layers 175, 174, and 173. Next, plugs 176 are formed so as to fit into the openings.

[0385] Then, if Figure 6A As shown, a conductive film 151f, which will later become the conductive layers 151R, 151G, 151B, and 151C, and a conductive film 152f, which will later become the conductive layers 152R, 152G, 152B, and 152C, are formed on the plug 176 and the insulating layer 175. A metal material can be used as the conductive film 151f, for example. An oxide containing one or more selected from the group consisting of indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used as the conductive film 152f.

[0386] Then, if Figure 6A As shown in FIG. 1 , a resist mask 191 is formed on the conductive film 152f. The resist mask 191 can be formed by applying a photosensitive material (photoresist), exposing the material to light, and developing the material.

[0387] Then, if Figure 6B As shown, for example, the conductive film 151f and the conductive film 152f are removed in the region that does not overlap with the resist mask 191. Thus, the conductive layer 151 and the conductive layer 152 are formed.

[0388] Then, if Figure 6C As shown, the resist mask 191 is removed. The resist mask 191 can be removed by ashing using oxygen plasma, for example.

[0389] Then, if Figure 6D 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 152R, the conductive layer 152G, the conductive layer 152B, the conductive layer 152C and the insulating layer 175.

[0390] 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, a silicon oxynitride film can be used.

[0391] Then, if Figure 6E 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.

[0392] Then, if Figure 7A As shown in FIG. 1 , an 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 7A As shown, the organic compound film 103Rf is not formed on the conductive layer 152C.

[0393] Then, if Figure 7A As shown, a conductive film 102Rf, which will serve as a second electrode, is formed on the organic compound film 103Rf. Then, a sacrificial film 158Rf and a mask film 159Rf are formed on the conductive film 102Rf. By forming the sacrificial film 158Rf and the mask film 159Rf on the organic compound film 103Rf with the conductive film 102Rf interposed therebetween, damage to the organic compound film 103Rf during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-emitting device.

[0394] When the second electrode 102 is an electrode for extracting light, a material having visible light transmittance is preferably used as the conductive film 102Rf. For example, a material having a visible light reflectance of 20% or more and 80% or less, preferably 40% or more and 70% or less, and a resistivity of 1×10 -2 In addition, when a material with low light transmittance such as metal or alloy is used as the conductive film 102Rf, the thickness can be made thick enough to transmit visible light (for example, The transparent conductive layer is formed with a thickness of 1 nm to 10 nm. Specifically, in addition to the oxide conductive layer represented by ITO, it also includes an oxide semiconductor layer or an organic conductive layer containing organic matter. As the organic conductive layer containing organic matter, for example, a layer containing a composite material formed by mixing an organic compound and an electron donor (donor), a layer containing a composite material formed by mixing an organic compound and an electron acceptor (acceptor), etc. can be cited. In addition, the resistivity of the transparent conductive layer is preferably 1×10 5 Ω·cm or less, more preferably 1×10 4 Ω·cm or less.

[0395] The conductive film 102Rf can be deposited by a dry method such as vacuum evaporation or sputtering, an inkjet method, or a spin coating method. Alternatively, it can be formed by a wet method such as a sol-gel method or a wet method using a metal paste. In particular, the conductive film 102Rf formed on and in contact with the organic compound film 103Rf is preferably formed using a formation method that minimizes damage to the organic compound film 103Rf. For example, the ALD method or vacuum evaporation method is preferably used.

[0396] Furthermore, the sacrificial film 158Rf and the mask film 159Rf are appropriately provided as needed. For example, if the conductive film 102Rf can sufficiently protect the organic compound film 103Rf, the step of forming the sacrificial film 158Rf can be omitted by forming the mask film 159Rf on the conductive film 102Rf. Alternatively, if the etching selectivity between the organic compound film 103Rf and the conductive film 102Rf and between the conductive film 102Rf and the sacrificial film 158Rf is sufficiently high, the sacrificial film 158Rf can be used as a mask, and thus the step of forming the mask film 159Rf can also be omitted.

[0397] 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 with the organic compound film 103Rf. The mask film 159Rf is a film having a large etching selectivity with the sacrificial film 158Rf.

[0398] Furthermore, the conductive film 102Rf, the sacrificial film 158Rf, and the mask film 159Rf are preferably formed at a temperature lower than the heat resistance temperature of the organic compound film 103Rf. The substrate temperature during formation of 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. Because the light-emitting device of one embodiment of the present invention includes the first compound, a display device can be provided that exhibits excellent display quality even after undergoing a higher-temperature heating step.

[0399] As the sacrificial film 158Rf and the mask film 159Rf, films that can be removed by wet etching or dry etching are preferably used.

[0400] Note that the sacrificial film 158Rf is preferably denser than the mask film 159Rf. For example, ALD or vacuum evaporation is more preferable than sputtering.

[0401] 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.

[0402] For example, the sacrificial film 158Rf and the mask film 159Rf can each be made of a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, or tantalum, or an alloy containing such a metal material. Low-melting-point materials such as aluminum or silver are particularly preferred. Using a metal material that blocks ultraviolet light for one or both of the sacrificial film 158Rf and the mask film 159Rf is preferred because it prevents ultraviolet light from reaching the organic compound film 103Rf during pattern exposure, thereby suppressing degradation of the organic compound film 103Rf.

[0403] 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.

[0404] 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.

[0405] For example, semiconductor materials such as silicon and germanium are preferably used as the sacrificial film 158Rf and the mask film 159Rf because they have high affinity with the semiconductor manufacturing process. Alternatively, a compound containing the above semiconductor materials may be used.

[0406] Various inorganic insulating films can be used as the sacrificial film 158Rf and the mask film 159Rf. In particular, an oxide insulating film is preferred because it has higher adhesion to the organic compound film 103Rf than a nitride insulating film.

[0407] Then, if Figure 7A As shown, a resist mask 190R is formed. The resist mask 190R can be formed by applying a photosensitive material (photoresist), exposing it to light, and developing it.

[0408] Resist mask 190R is provided at a position overlapping conductive layer 152R. Resist mask 190R is preferably also provided at a position overlapping conductive layer 152C. This can prevent conductive layer 152C from being damaged during the manufacturing process of the display device.

[0409] Then, if Figure 7BAs shown, a portion of mask film 159Rf is removed using resist mask 190R to form mask layer 159R. Mask layer 159R remains on conductive layer 152R and conductive layer 152C. Resist mask 190R is then removed. Next, mask layer 159R is used as a mask (also referred to as a hard mask) to remove a portion of sacrificial film 158Rf and a portion of conductive film 102Rf, thereby forming sacrificial layer 158R and second electrode 102R.

[0410] By using the wet etching method, damage to the organic compound film 103Rf during processing of the conductive film 102Rf, the sacrificial film 158Rf, and the mask film 159Rf can be reduced compared to the case of using the dry etching method. When using the wet etching method, for example, it is preferable to use a developer, an alkaline aqueous solution such as a tetramethylammonium hydroxide (TMAH) aqueous solution, or an acidic aqueous solution such as a chemical solution of dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0411] Furthermore, when dry etching is used in processing the sacrificial film 158Rf and the conductive film 102Rf, degradation of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as an etching gas.

[0412] The resist mask 190R can be removed by the same method as the resist mask 191 .

[0413] Then, if Figure 7B As shown, the organic compound film 103Rf is subjected to hard masking to form the organic compound layer 103R. For example, the organic compound layer 103R is formed by removing a portion of the conductive film 102Rf and a portion of the organic compound film 103Rf using the mask layer 159R and the sacrificial layer 158R as hard masks.

[0414] Therefore, if Figure 7B As shown, the stacked structure of the organic compound layer 103R, the second electrode 102R, 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.

[0415] The organic compound film 103Rf is preferably processed using anisotropic etching, particularly preferably anisotropic dry etching. Alternatively, wet etching may be used.

[0416] When the dry etching method is used, by not using an oxygen-containing gas as the etching gas, degradation of the organic compound film 103Rf can be suppressed.

[0417] Alternatively, 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 at low power while maintaining a sufficient etching rate. This can minimize damage to the organic compound film 103Rf and prevent defects such as adhesion of reaction products generated during etching.

[0418] When dry etching is used, for example, a gas containing one or more Group 18 elements such as H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, He, and Ar is preferably used as the etching gas. Alternatively, a gas containing one or more of the above-mentioned gases and oxygen is preferably used as the etching gas. Alternatively, oxygen gas may be used as the etching gas.

[0419] Then, if Figure 8A As shown, an organic compound film 103Gf which will later become the organic compound layer 103G and a conductive film 102Gf which will later become the second electrode 102G are formed.

[0420] The organic compound film 103Gf can be formed using the same method as that used to form the organic compound film 103Rf. Furthermore, the organic compound film 103Gf can have the same structure as that of the organic compound film 103Rf. Furthermore, the conductive film 102Gf can be formed using the same method as that used to form the conductive film 102Gf. Furthermore, the conductive film 102Gf can have the same structure as that of the conductive film 102Rf.

[0421] Then, if Figure 8A As shown, a sacrificial film 158Gf and a mask film 159Gf are sequentially formed. Then, a resist mask 190G is formed. The materials and formation 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 formation methods of the resist mask 190G are the same as those applicable to the resist mask 190R.

[0422] The resist mask 190G is provided at a position overlapping with the conductive layer 152G.

[0423] Then, if Figure 8B As shown, a portion of the mask film 159Gf is removed using a resist mask 190G, thereby forming a mask layer 159G. Mask layer 159G remains on the conductive layer 152G. Resist mask 190G is then removed. Using mask layer 159G as a mask, a portion of the sacrificial film 158Gf and a portion of the conductive film 102Gf are removed, thereby forming the sacrificial layer 158G and the second electrode 102G. Next, the organic compound film 103Gf is processed to form the organic compound layer 103G.

[0424] Then, if Figure 8C As shown, an organic compound film 103Bf and a conductive film 102Bf which will later become the second electrode 102B are formed.

[0425] The organic compound film 103Bf can be formed using the same method as that used for forming the organic compound film 103Rf. Furthermore, the organic compound film 103Bf can have the same structure as that of the organic compound film 103Rf. Furthermore, the conductive film 102Bf can be formed using the same method as that used for forming the conductive film 102Rf. Furthermore, the conductive film 102Bf can have the same structure as that of the conductive film 102Rf.

[0426] Then, if Figure 8C As shown, sacrificial film 158Bf and mask film 159Bf are sequentially formed. Then, resist mask 190B is formed. The materials and formation methods of sacrificial film 158Bf and mask film 159Bf are the same as those used for sacrificial film 158Rf and mask film 159Rf. The materials and formation methods of resist mask 190B are the same as those used for resist mask 190R.

[0427] The resist mask 190B is provided at a position overlapping with the conductive layer 152B.

[0428] Then, if Figure 8D As shown, a portion of the mask film 159Bf is removed using a resist mask 190B, thereby forming a mask layer 159B. The mask layer 159B remains on the conductive layer 152B. The resist mask 190B is then removed. Next, using the mask layer 159B as a mask, a portion of the sacrificial film 158Bf and a portion of the conductive film 102Bf are removed, thereby forming the sacrificial layer 158B and the second electrode 102B. 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 hard masks, a portion of the organic compound film 103Bf is removed, thereby forming the organic compound layer 103B.

[0429] Therefore, if Figure 8D As shown in FIG. 1 , the stacked structure of the organic compound layer 103B, the second electrode 102B, 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.

[0430] Note that the side surfaces of the stacked structure of the organic compound layer 103R and the second electrode 102R, the stacked structure of the organic compound layer 103G and the second electrode 102G, and the stacked structure of the organic compound layer 103B and the second electrode 102B are preferably perpendicular or substantially perpendicular to the surface on which they are formed. For example, the angle formed between the surface on which they are formed and these side surfaces is preferably not less than 60 degrees and not more than 90 degrees.

[0431] As described above, the distance between two adjacent stacked structures of the organic compound layer 103R and the second electrode 102R, the organic compound layer 103G and the second electrode 102G, and the organic compound layer 103B and the second electrode 102B formed using photolithography can be reduced to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. This distance can be determined, for example, based on the distance between the opposing ends of two adjacent organic compound layers in the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. By reducing the distance between the island-shaped organic compound layers, a display device with high definition and a large aperture ratio can be provided. Furthermore, the distance between the first electrodes of adjacent light-emitting devices can be reduced to, for example, 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, or 2 μm or less. Furthermore, the distance between the first electrodes of adjacent light-emitting devices is preferably between 2 μm and 5 μm.

[0432] Then, if Figure 9A As shown, mask layer 159R, mask layer 159G, and mask layer 159B are preferably removed.

[0433] Note that in the case where the light emitting device is configured as Figure 23G In the case of the so-called stripe configuration shown in FIG, the second electrode 102 can be formed as a continuous layer in the light-emitting device of the same luminous color. In this case, the auxiliary electrode 105 described later may not be formed, so the mask layer 159 may not be removed in the case of bottom emission. Figure 8D After the process enter Figure 11B In addition, in the case of top emission, if the sacrificial layer 158 and the mask layer 159 are light-transmissive, they may not be removed. Figure 8D After the process enter Figure 11B In the case of no light transmittance, it is preferred to remove the sacrificial layer 158 and the mask layer 159. After removing the sacrificial layer 158 and / or the mask layer 159 ( Figure 9A After the process), enter Figure 11B process.

[0434] The mask layer can be removed by the same method as that used in the mask film processing step. In particular, wet etching can reduce damage to the organic compound layer 103 during mask layer removal compared to dry etching.

[0435] 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.

[0436] After removing the mask layer, a drying process may be performed to remove surface water. For example, heat treatment may be performed in an inert gas atmosphere or a reduced pressure atmosphere. 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. Using a reduced pressure atmosphere is preferred because it allows drying at a lower temperature.

[0437] Then, if Figure 9B As shown, an inorganic insulating film 125f is formed.

[0438] Then, if Figure 9C As shown in FIG. 1 , an insulating film 127 f which will later become the insulating layer 127 is formed on the inorganic insulating film 125 f.

[0439] The substrate temperature during formation of 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.

[0440] 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.

[0441] The inorganic insulating film 125f is preferably formed using, for example, ALD. Using ALD is preferred because it reduces deposition damage and allows for deposition of a film with high coverage. For example, an aluminum oxide film is preferably formed using ALD as the inorganic insulating film 125f.

[0442] The insulating film 127f is preferably formed using the aforementioned wet deposition method. For example, the insulating film 127f is preferably formed using a photosensitive material by spin coating, and more specifically, is preferably formed using a photosensitive resin composition containing an acrylic resin.

[0443] 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 layers 152R, 152G, and 152B and around the conductive layer 152C.

[0444] The width of the insulating layer 127 to be formed later can be controlled by the exposed region of the insulating film 127f. In this embodiment, the insulating layer 127 is processed so that a portion overlaps with the top surface of the conductive layer 151.

[0445] 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).

[0446] Then, if Figure 10A As shown, development is performed to remove the exposed regions in the insulating film 127f, thereby forming the insulating layer 127a.

[0447] Then, if Figure 10B As shown, etching is performed using the insulating layer 127a as a mask to remove a portion of the inorganic insulating film 125f. Note that while the sacrificial layer 158 remains, the thickness of a portion of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B is reduced. Thus, the inorganic insulating layer 125 is formed under the insulating layer 127a. Furthermore, the surfaces of the thinner portions of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are exposed. Note that below, the etching process using the insulating layer 127a as a mask may be referred to as the first etching process.

[0448] The first etching process can be performed by dry etching or wet etching. Depositing the inorganic insulating film 125f using the same material as the sacrificial layers 158R, 158G, and 158B is preferred because the first etching process can be performed all at once. Furthermore, if the sacrificial layer 158 is not formed, the surfaces of the second electrodes 102R, 102B, and 102G are exposed by the first etching process.

[0449] When dry etching is performed, a chlorine-based gas is preferably used. As the chlorine-based gas, one or a mixture of two or more of Cl2, BCl3, SiCl4, and CCl4 can be used. Furthermore, one or a mixture of two or more of oxygen, hydrogen, helium, and argon can be appropriately added to the chlorine-based gas. For example, when sacrificial layer 158 remains, dry etching can be used to form thin regions of sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B with excellent in-plane uniformity.

[0450] As a dry etching apparatus, a dry etching apparatus having a high-density plasma source can be used. As a dry etching apparatus having a high-density plasma source, for example, an inductively coupled plasma (ICP) etching apparatus can be used. Alternatively, a capacitively coupled plasma (CCP) etching apparatus including parallel plate electrodes can be used.

[0451] In addition, it is preferred to use wet etching for the first etching process. By using the wet etching method, the damage to the processed structure 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, a TMAH aqueous solution 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. Note that 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 process can be performed at one time, so it is preferred.

[0452] The first etching process does not completely remove the sacrificial layers 158R, 158G, and 158B, but stops the etching process while the thickness of the sacrificial layers is reduced. Thus, by leaving the corresponding sacrificial layers 158R, 158B, and 158G on the second electrodes 102R, 102B, and 102G, damage to the structure including the organic compound layer 103 can be prevented during subsequent processing steps.

[0453] 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 this exposure after development, the transparency of the insulating layer 127a can sometimes be improved. In addition, the substrate temperature required for the heat treatment in a later step to deform the insulating layer 127a into a tapered shape can sometimes be reduced.

[0454] Here, by providing an oxygen blocking insulating layer (e.g., an aluminum oxide film) as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the diffusion of oxygen into the second electrode 102R, the second electrode 102B, and the second electrode 102G can be reduced, or the reduction in conductivity due to metal oxidation can be reduced.

[0455] 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 10C ). 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.

[0456] Note that in the first etching process, by not completely removing the sacrificial layers 158R, 158G, and 158B, but leaving the sacrificial layers 158R, 158G, and 158B in a reduced thickness, damage and degradation of the processed structure including the organic compound layer 103 during the heat treatment can be prevented. This improves the reliability of the light-emitting device.

[0457] Then, if Figure 11A As shown, etching is performed using insulating layer 127 as a mask. Furthermore, while sacrificial layer 158 remains, portions of sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B are removed. Consequently, openings are formed in each of sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B, exposing the top surfaces of second electrode 102R, second electrode 102B, second electrode 102G, and conductive layer 152C. Note that this etching process may be referred to as a second etching process hereinafter.

[0458] Note that when the sacrificial layer 158 is not formed, since the surfaces of the second electrodes 102R, 102B, and 102G are exposed by the first etching process, the second etching process described later can be omitted.

[0459] The end portion of the inorganic insulating layer 125 is covered with the insulating layer 127. In addition, when the sacrificial layer 158 remains, a portion of the end portion of the sacrificial layer 158G (specifically, the tapered portion formed by the first etching process) is covered by the insulating layer 127, and the tapered portion formed by the second etching process is exposed.

[0460] The second etching process is performed using wet etching. Wet etching can reduce damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B compared to dry etching. For example, wet etching can be performed using an alkaline solution or an acidic solution. To prevent dissolution of the organic compound layer 103, wet etching is preferably performed using an aqueous solution.

[0461] Then, if Figure 11B As shown, the auxiliary electrode 105 is formed over the second electrode 102R, the second electrode 102B, the second electrode 102G, the conductive layer 152C, and the insulating layer 127. The auxiliary electrode 105 can be formed by a method such as sputtering or vacuum evaporation.

[0462] Then, if Figure 11B As shown, a protective layer 131 is formed on the auxiliary electrode 105. The protective layer 131 can be formed by vacuum evaporation, sputtering, CVD, ALD or other methods.

[0463] Next, the substrate 120 is bonded to the protective layer 131 using the resin layer 122, thereby manufacturing the display device. As described above, in the method for manufacturing a display device according to one embodiment of the present invention, the insulating layers 156 (insulating layers 156R, 156G, and 156B) are provided so as to include regions overlapping with the side surfaces 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. This improves the yield of the display device and prevents defects.

[0464] As described above, in a method for manufacturing a display device of one embodiment 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 between sub-pixels can be suppressed. Thus, crosstalk can be prevented to realize a display device with extremely high contrast. In addition, even a display device including a tandem light-emitting device manufactured using photolithography can provide a display device with good characteristics.

[0465] Implementation 4 In this embodiment, a display device which is one embodiment of the present invention is described.

[0466] 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 the display portion of information terminal devices (wearable devices) such as watches and bracelets, as well as the display portion of wearable devices such as head-mounted displays (HMDs) for VR devices and glasses-type AR devices that can be worn on the head.

[0467] Furthermore, 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 electronic devices with large screens, such as televisions, desktop or notebook personal computers, monitors for computers, etc., digital signage, and large-scale game machines such as pinball machines; digital cameras; digital video cameras; digital photo frames; mobile phones; portable game consoles; portable information terminals; and audio reproduction devices.

[0468] [Display module] Figure 12A 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 devices 100B and 100E described later.

[0469] 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 allows light from each pixel provided in a pixel portion 284 described below to be viewed.

[0470] Figure 12B This is a perspective schematic diagram of the structure on one side of a substrate 291. A circuit portion 282, a pixel circuit portion 283 on circuit portion 282, and a pixel portion 284 on pixel circuit portion 283 are stacked on substrate 291. Furthermore, a terminal portion 285 for connecting to an FPC 290 is provided on a portion of substrate 291 that does not overlap with 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 wiring lines.

[0471] The pixel portion 284 includes a plurality of pixels 284 a arranged periodically. Figure 12B 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. Figure 12B Pixel 284a is shown having Figure 5A An example of a case where the pixel 178 shown has the same structure.

[0472] The pixel circuit portion 283 includes a plurality of pixel circuits 283 a arranged periodically.

[0473] One pixel circuit 283a controls driving of a plurality of elements included in one pixel 284a.

[0474] The circuit unit 282 includes circuits for driving each pixel circuit 283a of the pixel circuit unit 283. For example, it preferably includes one or both of a gate line driver circuit and a source line driver circuit. In addition, it may include at least one of a calculation circuit, a storage circuit, and a power supply circuit.

[0475] 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.

[0476] 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 below the pixel portion 284 , so that the display portion 281 may have an extremely high aperture ratio (effective display area ratio).

[0477] This high-definition display module 280 is suitable for use in VR devices such as HMDs or glasses-type AR devices. For example, because display module 280 has an extremely high-definition display portion 281, even when the display portion is magnified through a lens, the user does not see pixels, thereby achieving a highly immersive display. Furthermore, display module 280 is not limited to this application and can also be applied to electronic devices with relatively small display portions.

[0478] [Display device 100A] Figure 13A 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 .

[0479] Substrate 301 is equivalent to Figure 12A and Figure 12B The transistor 310 is a transistor having a channel formation region in the substrate 301. As the substrate 301, 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 serves as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and serves as a gate insulating layer. The low resistance region 312 is a region doped with impurities in the substrate 301 and serves as a source or drain. The insulating layer 314 covers the side surfaces of the conductive layer 311.

[0480] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0481] Furthermore, an insulating layer 261 is provided to cover the transistor 310 , and the capacitor 240 is provided over the insulating layer 261 .

[0482] Capacitor 240 includes conductive layer 241, conductive layer 245, and insulating layer 243 therebetween. Conductive layer 241 serves as one electrode of capacitor 240, conductive layer 245 serves as the other electrode of capacitor 240, and insulating layer 243 serves as a dielectric of capacitor 240.

[0483] Conductive layer 241 is provided on insulating layer 261 and embedded in insulating layer 254. Conductive layer 241 is electrically connected to one of the source and drain of transistor 310 via plug 271 embedded in insulating layer 261. Insulating layer 243 is provided to cover conductive layer 241. Conductive layer 245 is provided in a region overlapping conductive layer 241 with insulating layer 243 interposed therebetween.

[0484] An insulating layer 255 is provided to cover capacitor 240. Insulating layer 174 is provided on insulating layer 255, and insulating layer 175 is provided on insulating layer 174. Light-emitting devices 130R, 130G, and 130B are provided on insulating layer 175. Insulators are provided in the regions between adjacent light-emitting devices.

[0485] Insulating layer 156R is provided so as to include a region overlapping with the side surfaces of conductive layer 151R, insulating layer 156G is provided so as to include a region overlapping with the side surfaces of conductive layer 151G, and insulating layer 156B is provided so as to include a region overlapping with the side surfaces of conductive layer 151B. Furthermore, conductive layer 152R is provided so as to cover conductive layer 151R and insulating layer 156R, conductive layer 152G is provided so as to cover conductive layer 151G and insulating layer 156G, and conductive layer 152B is provided so as to cover conductive layer 151B and insulating layer 156B. Note that insulating layer 156 may not be provided.

[0486] Conductive layer 151R, conductive layer 151G, and conductive layer 151B are electrically connected to one of the source and drain of transistor 310 via plug 256 embedded in insulating layer 243, insulating layer 255, insulating layer 174, and insulating layer 175, conductive layer 241 embedded in insulating layer 254, and plug 271 embedded in insulating layer 261. Various conductive materials can be used for the plug.

[0487] Furthermore, a protective layer 131 is provided on the light emitting devices 130R, 130G, and 130B via the auxiliary electrode 105. The substrate 120 is bonded to the protective layer 131 via the resin layer 122. The details of the components of the light emitting devices 130 to the substrate 120 can be referred to Embodiment 3. The substrate 120 corresponds to Figure 12A substrate 292.

[0488] Figure 13B Show Figure 13A This is a modified example of the display device 100A shown. Figure 13B 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. Figure 13B In the display device shown, the light emitting device 130 can emit white light, for example. In addition, for example, the colored layer 132R, the colored layer 132G, and the colored layer 132B can transmit red light, green light, and blue light, respectively.

[0489] [Display device 100B] Figure 14 A perspective view showing a display device 100B is shown. Figure 15 A cross-sectional view of the display device 100B is shown.

[0490] The display device 100B has a structure in which a substrate 352 and a substrate 351 are bonded together. Figure 14 , the substrate 352 is indicated by a dotted line.

[0491] The display device 100B includes a pixel portion 177 , a connection portion 140 , a circuit 356 , a wiring 355 , and the like. Figure 14 The example in which the display device 100B is mounted with IC354 and FPC353 is shown. Figure 14 The structure shown is called a display module including the display device 100B, an IC (integrated circuit), and an FPC. Here, a substrate of a display device with a connector such as an FPC mounted thereon or a substrate with an IC mounted thereon is called a display module.

[0492] The connection portion 140 is disposed outside the pixel portion 177. There may be one or more connection portions 140. In the connection portion 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.

[0493] As the circuit 356 , for example, a scan line driver circuit can be used.

[0494] The wiring 355 has a function of supplying signals and power to the pixel portion 177 and the circuit 356. The signals and power are input to the wiring 355 from the outside through the FPC 353 or from the IC 354.

[0495] Figure 14 An example is shown in which an IC 354 is provided on a substrate 351 using a COG (Chip On Glass) method or a COF (Chip On Film) method. For example, an IC including a scan line driver circuit or a signal line driver circuit can be used as the IC 354. Note that the display device 100B and the display module do not necessarily need to be provided with an IC. Alternatively, the IC can be mounted on an FPC using a COF method, for example.

[0496] Figure 15 An example of a cross section of a region including a portion of the FPC 353 , a portion of the circuit 356 , a portion of the pixel portion 177 , and a portion of the connecting portion 140 of the display device 100C is shown.

[0497] [Display device 100C] Figure 15 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 .

[0498] For details of the light emitting device 130R, the light emitting device 130G, and the light emitting device 130B, refer to Embodiment 1 or Embodiment 2.

[0499] Light-emitting device 130R includes a conductive layer 224R, a conductive layer 151R on conductive layer 224R, and a conductive layer 152R on conductive layer 151R. Light-emitting device 130G includes a conductive layer 224G, a conductive layer 151G on conductive layer 224G, and a conductive layer 152G on conductive layer 151G. Light-emitting device 130B includes a conductive layer 224B, a conductive layer 151B on conductive layer 224B, and a conductive layer 152B on conductive layer 151B.

[0500] Conductive layer 224R is connected to conductive layer 222b included in transistor 205 through an opening provided in insulating layer 214. An end portion of conductive layer 151R is located outside an end portion of conductive layer 224R. Insulating layer 156R is provided to include a region in contact with a side surface of conductive layer 151R, and conductive layer 152R is provided to cover conductive layer 151R and insulating layer 156R.

[0501] 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.

[0502] 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.

[0503] Layer 128 flattens the concave portions of conductive layers 224R, 224G, and 224B. Conductive layers 151R, 151G, and 151B, electrically connected to conductive layers 224R, 224G, and 224B, are provided over conductive layers 224R, 224G, and 224B, and layer 128. Therefore, the areas overlapping the concave portions of conductive layers 224R, 224G, and 224B can also be used as light-emitting areas, thereby increasing the pixel aperture ratio.

[0504] Layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used as appropriate for layer 128. In particular, layer 128 is preferably formed of an insulating material, more preferably an organic insulating material. For example, the organic insulating materials described above for insulating layer 127 can be used for layer 128.

[0505] A protective layer 131 is provided on the light emitting devices 130R, 130G and 130B via the auxiliary electrode 105. 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 can adopt a solid sealing structure or a hollow sealing structure. Figure 15 In the embodiment, the space between substrate 352 and substrate 351 is filled with adhesive layer 142, i.e., a solid sealing structure is adopted. Alternatively, the space can be filled with an inert gas (such as nitrogen or argon), i.e., a hollow sealing structure is adopted. In this case, adhesive layer 142 can also be arranged so as not to overlap with the light-emitting device. In addition, a resin different from the adhesive layer 142 arranged in a frame shape can also be used to fill the space.

[0506] Figure 15In the example shown below, the connection portion 140 includes a conductive layer 224C formed by processing the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive layer 151C formed by processing the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive layer 152C formed by processing the same conductive film as the conductive layers 152R, 152G, and 152B. Figure 15 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.

[0507] The display device 100C is a top-emission display device. The light-emitting device emits light toward the substrate 352. The substrate 352 is preferably made of a material that is highly transmissive to visible light. The pixel electrode is made of a material that reflects visible light, while the counter electrode (second electrode 102) and auxiliary electrode 105 are made of a material that transmits visible light.

[0508] Insulating layer 211, insulating layer 213, insulating layer 215, and insulating layer 214 are sequentially provided on substrate 351. A portion of insulating layer 211 serves as a gate insulating layer for each transistor. A portion of insulating layer 213 serves as a gate insulating layer for each transistor. Insulating layer 215 is provided to cover the transistors. Insulating layer 214 is provided to cover the transistors and serves as a planarization layer. There are no particular restrictions on the number of gate insulating layers or insulating layers covering the transistors; they can be one or two or more.

[0509] As the insulating layer 211 , the insulating layer 213 , and the insulating layer 215 , an inorganic insulating film is preferably used.

[0510] As the insulating layer 214 serving as a planarizing layer, an organic insulating layer is preferably used.

[0511] Transistor 201 and transistor 205 include: a conductive layer 221 serving as a gate; an insulating layer 211 serving as a gate insulating layer; a conductive layer 222a and a conductive layer 222b serving as a source and a drain; a semiconductor layer 231; an insulating layer 213 serving as a gate insulating layer; and a conductive layer 223 serving as a gate.

[0512] Connecting portion 204 is provided in a region of substrate 351 that is not overlapped by substrate 352. In connecting portion 204, the source electrode or drain electrode of transistor 201 is electrically connected to FPC 353 via conductive layer 166 and connecting layer 242. In the example shown, conductive layer 166 has a stacked structure comprising a conductive film processed from the same conductive film as conductive layers 224R, 224G, and 224B, a conductive film processed from the same conductive film as conductive layers 151R, 151G, and 151B, and a conductive film processed from the same conductive film as conductive layers 152R, 152G, and 152B. Conductive layer 166 is exposed on the top surface of connecting portion 204. Therefore, connecting portion 204 and FPC 353 can be electrically connected via connecting layer 242.

[0513] A light shielding layer 157 is preferably provided on the substrate 351 side surface of the substrate 352. The light shielding layer 157 can be provided between adjacent light emitting devices, in the connection portion 140 and the circuit 356, etc. Various optical components can be arranged outside the substrate 352.

[0514] The substrate 351 and the substrate 352 can each adopt a material that can be used for the substrate 120 .

[0515] As the adhesive layer 142 , a material that can be used for the resin layer 122 can be used.

[0516] As the connection layer 242 , an anisotropic conductive film (ACF), anisotropic conductive paste (ACP), or the like can be used.

[0517] [Display device 100D] Figure 16 The display device 100D shown is Figure 15 The main difference of the illustrated display device 100C from the display device 100D is that the display device is a bottom emission type display device.

[0518] Light emitted by the light emitting device is emitted to the substrate 351. A material having high transmittance to visible light is preferably used for the substrate 351. On the other hand, there is no limitation on the transmittance of the material used for the substrate 352.

[0519] A light-shielding layer is preferably formed between the substrate 351 and the transistor 201 and between the substrate 351 and the transistor 205 . Figure 16 An example is shown in which a light-shielding layer 317 is provided over a substrate 351 , an insulating layer 153 is provided over the light-shielding layer 317 , and transistors 201 , 205 , and the like are provided over the insulating layer 153 .

[0520] 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.

[0521] 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.

[0522] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are all made of a material having high transmittance to visible light. The second electrode 102 is preferably made of a material that reflects visible light.

[0523] Note that although Figure 16 The light emitting device 130G is not shown in the figure, but the light emitting device 130G is also provided.

[0524] in addition, Figure 16 The examples in which the top surface of the layer 128 has a flat portion are shown in the figures, but the shape of the layer 128 is not particularly limited.

[0525] [Display device 100D2] Figure 17A The display device 100D2 shown is Figure 16 The display device 100D2 is an example of a bottom emission type display device different from the display device 100D shown in FIG. The display device 100D2 is different from the display device 100D in that it includes an organic resin layer 180. Figure 16 The same components are denoted by reference numerals. Figure 16 Records of.

[0526] in addition, Figure 17B 1 shows a top-view layout of a pixel 178 (pixel 178 a and pixel 178 b ) including sub-pixels 110 (sub-pixel 110R, sub-pixel 110G, and sub-pixel 110B). Figure 17C The top view shows the organic resin layer 180 in the region where the sub-pixels 110R and 110G included in the pixel 178 are formed. The width 110Rw of the light emitting region of the sub-pixel 110R is defined between the light shielding layers 317 .

[0527] like Figure 17A As shown, the organic resin layer 180 is disposed on the insulating layer 214. Figure 17A The area enclosed by the dotted line and Figure 17CAs shown, organic resin layer 180 includes curved recesses 181 (recesses 181a and 181b) at least in the region where the subpixels are formed. Alternatively, recesses 181, like recess 181c, can be positioned outside the light-emitting region. The provision of recesses 181c allows light generated in the region overlapping with light-shielding layer 317, or light entering the region overlapping with light-shielding layer 317, to be refracted and extracted from the light-emitting region to the outside, thereby improving light emission efficiency.

[0528] A plurality of recesses 181 may be formed in a matrix. The recesses 181a and 181b may be provided in contact with each other or with a flat surface therebetween.

[0529] In addition, the top surface of the concave portion is hexagonal ( Figure 17C ), the cross-sectional shape is semicircular ( Figure 17A ) example, other shapes can also be adopted as needed. For example, the top surface shape of this recessed portion can also be polygons such as triangle, quadrilateral (including rectangle and square), pentagon, the above-mentioned polygon with rounded corners, ellipse or circle, etc.

[0530] The organic resin layer 180 may be an insulating layer containing an organic material. For example, the organic resin layer 180 may be made of acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin, or precursors of the above resins. Alternatively, the organic resin layer 180 may be made of an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin.

[0531] In addition, a photosensitive resin may be used for the organic resin layer 180. The photosensitive resin may be a photoresist. The photosensitive resin may be a positive type material or a negative type material.

[0532] Organic resin layer 180 may contain a material that absorbs visible light. For example, organic resin layer 180 itself may be composed of a material that absorbs visible light, or it may contain a pigment that absorbs visible light. Examples of organic resin layer 180 include resins that can be used as color filters that transmit red, blue, or green light and absorb other light, or resins that contain carbon black as a pigment and are used as a black matrix.

[0533] The first electrode 101 is formed on the organic resin layer 180 , the organic compound layer 103 is formed on the first electrode 101 , and the second electrode 102 is formed on the organic compound layer 103 .

[0534] Furthermore, the first electrode 101 formed on the organic resin layer 180 also has recesses along the recesses of the organic resin layer 180. Furthermore, the organic compound layer 103 formed on the first electrode 101 also has recesses along the recesses of the first electrode 101. Furthermore, the second electrode 102 formed on the organic compound layer 103 also has recesses along the recesses of the organic compound layer 103. Furthermore, the auxiliary electrode 105 formed on the second electrode 102 also has recesses along the recesses of the second electrode 102. In other words, the recesses of the organic resin layer 180, the first electrode 101, the organic compound layer 103, the second electrode 102, and the auxiliary electrode 105 have a structure that overlaps with each other.

[0535] The second electrode 102 is provided on the organic compound layer 103 and the insulating layer 127 , and the auxiliary electrode 105 is provided on the second electrode 102 . The protective layer 131 is provided on the auxiliary electrode 105 and is bonded to the substrate 352 via the adhesive layer 142 .

[0536] In addition, although 17A to 17C The light emitting device 130G and the light emitting device 130B are not shown in FIG. 1 , but the light emitting device 130G and the light emitting device 130B are provided.

[0537] Since the light-emitting device according to one embodiment of the present invention including the organic resin layer 180 has the structure described in Embodiment Mode 1 or 2, an organic semiconductor device with low driving voltage and excellent characteristics can be provided.

[0538] [Display device 100E] Figure 18 The display device 100E shown is Figure 15 In the illustrated variation of the display device 100C, the display device 100E differs from the display device 100C primarily in that the display device 100E includes a colored layer 132R, a colored layer 132G, and a colored layer 132B.

[0539] In display device 100E, light-emitting device 130 includes a region that overlaps with one of colored layer 132R, colored layer 132G, and colored layer 132B. Colored layer 132R, colored layer 132G, and colored layer 132B may be provided on a surface of substrate 352 on the substrate 351 side. Ends of colored layer 132R, end portions of colored layer 132G, and end portions of colored layer 132B may overlap with light-shielding layer 157.

[0540] In the display device 100E, for example, the colored layers 132R, 132G, and 132B can transmit red light, green light, and blue light, respectively. Alternatively, the display device 100E may have a structure in which the colored layers 132R, 132G, and 132B are provided between the protective layer 131 and the adhesive layer 142.

[0541] [Display device 100E2] Figure 19A The display device 100E2 shown is Figure 18 In the modified example of the display device 100E shown in FIG. 1 , the colored layers 132R, 132G, and 132B are provided with micro lenses 182. Figure 18 For the same components, please refer to Figure 18 Records of.

[0542] in addition, Figure 19B 1 shows a top-view layout of a pixel 178 (pixel 178 a and pixel 178 b ) including sub-pixels 110 (sub-pixel 110R, sub-pixel 110G, and sub-pixel 110B). Figure 19C The top view shows the microlens 182 in the region where the sub-pixels 110R and 110G included in the pixel 178 are formed. The region where the auxiliary electrode 105 contacts the organic compound layer 103 corresponds to the width 110Gw of the light-emitting region of the sub-pixel 110G.

[0543] Figure 19A In the display device 100E2 shown, a planarizing film 143 is provided on a protective layer 131, and colored layers 132R, 132G, and 132B are provided on the planarizing film 143. A planarizing film 144 is provided to cover the colored layers 132R, 132G, and 132B. Microlenses 182 are provided on the planarizing film 144.

[0544] In addition, if Figure 19C As shown, a microlens 182 may be provided in each sub-pixel in the region where the sub-pixels are formed.

[0545] in addition, Figure 19C The top surface of the microlens 182 is shown as a hexagonal shape, but other shapes may be used as needed. For example, the top surface of the concave portion may be a polygon such as a triangle, a quadrilateral (including a rectangle and a square), a pentagon, any of the above polygons with rounded corners, an ellipse, or a circle.

[0546] The microlens 182 may be formed using the same material as the organic resin layer 180 .

[0547] This embodiment mode can be appropriately combined with other embodiment modes or examples. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be appropriately combined.

[0548] Implementation 5 In this embodiment, an electronic device according to one embodiment of the present invention is described.

[0549] The electronic device of this embodiment includes a display device according to one embodiment of the present invention in its display portion. The display device according to one embodiment of the present invention has high display performance and easily achieves high definition and high resolution. Therefore, it can be used in the display portion of various electronic devices.

[0550] Examples of electronic devices include televisions, desktop or notebook personal computers, displays for computers, digital signage, large-scale game consoles such as pinball machines, and other electronic devices with relatively large screens, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, portable information terminals, and sound reproduction devices.

[0551] In particular, because the display device according to one embodiment of the present invention can improve clarity, it is suitable for use in electronic devices with smaller display units. Examples of such electronic devices include watch-type and bracelet-type information terminals (wearable devices), wearable devices that can be worn on the head, such as head-mounted displays (HMDs), VR devices, and glasses-type AR and MR devices.

[0552] 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 substances, sound, time, hardness, electric field, current, voltage, electricity, radiation, flow, humidity, inclination, vibration, smell or infrared).

[0553] Reference 20A to 20D An example of a wearable device that can be worn on the head is described.

[0554] Figure 20A The electronic device 700A shown and Figure 20B 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.

[0555] The display device of one embodiment of the present invention can be applied to the display panel 751. This makes it possible to realize an electronic device with high reliability.

[0556] Both electronic devices 700A and 700B can project the image displayed on display panel 751 onto display area 756 in optical member 753. Since optical member 753 is light-transmissive, the user can see the image displayed on the display area superimposed on the image transmitted through optical member 753.

[0557] The electronic devices 700A and 700B may also be provided with cameras capable of capturing images of the front as imaging units. Furthermore, by providing acceleration sensors such as gyroscopes on the electronic devices 700A and 700B, the user's head orientation can be detected and an image corresponding to that orientation can be displayed on the display area 756.

[0558] The communication unit includes a wireless communication device through which, for example, a video signal can be supplied. Alternatively, 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.

[0559] Furthermore, electronic devices 700A and 700B are provided with batteries, and can be charged wirelessly, wired, or both.

[0560] The housing 721 may also be provided with a touch sensor module.

[0561] A variety of touch sensors can be used in the touch sensor module. For example, various touch sensors can be used, such as capacitance, resistive film, infrared, electromagnetic induction, surface acoustic wave, and optical. In particular, capacitance and optical sensors are preferred for use in the touch sensor module.

[0562] Figure 20C The electronic device 800A shown and Figure 20D The illustrated electronic devices 800B 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 .

[0563] 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.

[0564] The display unit 820 is provided at a position inside the housing 821 that can be viewed through the lens 832. In addition, by displaying different images on each of the pair of display units 820, three-dimensional display utilizing parallax can be performed.

[0565] The electronic devices 800A and 800B preferably have a mechanism capable of adjusting the left and right positions of the lens 832 and the display portion 820 so as to locate the lens 832 and the display portion 820 at the most appropriate positions according to the position of the user's eyes.

[0566] The user can use the mounting portion 823 to mount the electronic device 800A or the electronic device 800B on the head.

[0567] The imaging unit 825 has the 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. Alternatively, multiple cameras can be provided to support various viewing angles, such as telephoto and wide-angle.

[0568] The electronic device 800A may also include a vibration mechanism for use as a bone conduction headset.

[0569] Electronic devices 800A and 800B may both include input terminals. Cables for supplying video signals from video output devices and the like, and power for charging batteries provided in the electronic devices, may be connected to the input terminals.

[0570] The electronic device according to one embodiment of the present invention may have a function of wirelessly communicating with the earphone 750 .

[0571] Furthermore, the electronic device may include an earphone unit. Figure 20B The electronic device 700B shown includes an earphone unit 727. A portion of the wiring connecting the earphone unit 727 and the control unit may be arranged inside the housing 721 or the mounting portion 723.

[0572] same, Figure 20D The electronic device 800B shown includes an earphone unit 827. For example, a configuration in which the earphone unit 827 and the control unit 824 are connected in a wired manner may be employed.

[0573] 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.

[0574] Figure 21A The electronic device 6500 shown is a portable information terminal device that can be used as a smartphone.

[0575] An 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.

[0576] The display device of one embodiment of the present invention can be used for the display portion 6502. This enables a highly reliable electronic device to be realized.

[0577] Figure 21B 65 is a schematic cross-sectional view of an end portion of the housing 6501 on the microphone 6506 side.

[0578] 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.

[0579] 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).

[0580] In a region outside the display portion 6502, a portion of the display panel 6511 is folded back, and an FPC 6515 is connected to the folded back portion. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals provided on a printed circuit board 6517.

[0581] The display panel 6511 can be a flexible display manufactured using one of the methods of the present invention. This allows for an extremely lightweight electronic device. Furthermore, because the display panel 6511 is extremely thin, a large-capacity battery 6518 can be installed while reducing the thickness of the electronic device. Furthermore, by folding a portion of the display panel 6511 to provide a connection to the FPC 6515 on the back of the pixel unit, an electronic device with a narrow frame can be realized.

[0582] Figure 21C 10 shows an example of a television set. In a television set 7100, a display portion 7000 is incorporated into a housing 7171. Here, a structure in which the housing 7171 is supported by a stand 7173 is shown.

[0583] The display device of one embodiment of the present invention can be used as the display portion 7000. This makes it possible to implement a highly reliable electronic device.

[0584] The operation can be performed by using the operating switch provided by the housing 7171 and the remote control unit 7151 provided separately. Figure 21C Operation of television device 7100 is shown.

[0585] Figure 21D1 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 into the housing 7211 .

[0586] The display device of one embodiment of the present invention can be used as the display portion 7000. This makes it possible to implement a highly reliable electronic device.

[0587] Figure 21E and Figure 21F An example of digital signage is shown.

[0588] Figure 21E The digital signage 7300 shown includes a housing 7301, a display unit 7000, a speaker 7303, etc. In addition, it may include an LED light, operation keys (including a power switch or an operation switch), connection terminals, various sensors, a microphone, etc.

[0589] Figure 21F The digital signage 7400 is shown installed on a cylindrical pillar 7401. The digital signage 7400 includes a display unit 7000 installed along the curved surface of the pillar 7401.

[0590] exist Figure 21E and Figure 21F In this embodiment, the display device of one embodiment of the present invention can be used for the display portion 7000. Thus, a highly reliable electronic device can be achieved.

[0591] The larger the display unit 7000 is, the more information it can provide at one time. The larger the display unit 7000 is, the easier it is to attract people's attention, for example, it can improve the effectiveness of advertising.

[0592] like Figure 21E and Figure 21F As shown, the digital signage 7300 or the digital signage 7400 can preferably be linked to the information terminal device 7311 or the information terminal device 7411 such as a smartphone carried by the user through wireless communication.

[0593] Figures 22A to 22G 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 substances, sound, time, hardness, electric field, current, voltage, electricity, radiation, flow, humidity, inclination, vibration, smell or infrared), a microphone 9008, etc.

[0594] Figures 22A to 22GThe electronic devices shown have various functions. For example, they 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 using a touch panel; a function of displaying a calendar, date, or time; a function of controlling processing using various software (programs); a function of performing wireless communications; a function of reading and processing programs or data stored in a storage medium; and...

Claims

1. A light-emitting device, comprising: a first electrode on the first insulating layer; a second electrode on the first insulating layer; as well as an organic compound layer on the first insulating layer, wherein the first electrode contacts the first insulating layer, The organic compound layer is located between the first electrode and the second electrode, the second electrode and the organic compound layer are separated from the second electrode and the organic compound layer of at least one of a plurality of other light emitting devices adjacent to the light emitting device, When viewed from a direction perpendicular to the first insulating layer formed on the first electrode, the contour of the second electrode coincides or substantially coincides with the contour of the organic compound layer. The organic compound layer includes a light-emitting layer and an electron injection layer, The electron injection layer comprises a metal or a metal compound, a first organic compound and a second organic compound, The first organic compound includes a π-electron-deficient heteroaromatic ring, The second organic compound includes two or more heteroaromatic rings, The two or more heteroaromatic rings are bonded to each other or fused together and include three or more heteroatoms in total, Furthermore, the second organic compound acts as a multidentate ligand and interacts with the metal or the metal compound via two or more of the three or more heteroatoms.

2. The light emitting device according to claim 1, wherein the organic compound layer includes a P-type layer between the electron injection layer and the second electrode, The P-type layer includes a third organic compound having a hole transport property and a metal oxide or a fourth organic compound having at least one of a halogen group and a cyano group.

3. A light-emitting device, in, The light emitting device 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 on the same insulating surface; a second electrode group opposite to the first electrode group; and a first layer group between the first electrode group and the second electrode group, Wherein, the light emitting device includes a first electrode, a second electrode and a first layer, The first electrode is one of the first electrode group, The first electrode is independent of the plurality of light-emitting devices. The first layer is one of the first layer group, The first layer is independent according to the plurality of light-emitting devices, The second electrode is one of the second electrode group, The second electrode is independent of the plurality of light emitting devices. The second electrode and the first layer overlap with the first electrode, The first layer includes a light-emitting layer and an electron injection layer, The electron injection layer comprises a metal or a metal compound, a first organic compound and a second organic compound, The first organic compound includes a π-electron-deficient heteroaromatic ring, The second organic compound includes two or more heteroaromatic rings, The two or more heteroaromatic rings are bonded to each other or fused together and include three or more heteroatoms in total, The second organic compound acts as a multidentate ligand and interacts with the metal or the metal compound through two or more of the three or more heteroatoms. Furthermore, a distance between the first layer included in the light-emitting device and a first layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 0.5 μm and less than or equal to 5 μm.

4. The light emitting device according to claim 3, The first layer includes a P-type layer between the electron injection layer and the second electrode, The P-type layer includes a third organic compound having a hole transport property and a metal oxide or a fourth organic compound having at least one of a halogen group and a cyano group.

5. The light emitting device according to claim 3, When viewed from a direction perpendicular to the insulating surface, the outline of the second electrode is consistent or substantially consistent with the outline of the first layer.

6. The light emitting device according to claim 3, When viewed from a cross section, an end portion of the second electrode and an end portion of the first layer are aligned in a direction perpendicular or substantially perpendicular to the insulating surface.

7. The light emitting device according to claim 1, The second organic compound is represented by the general formula (G1-1): And in the general formula (G1-1), A 1 、A 2 and A 3 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms.

8. The light emitting device according to claim 1, The second organic compound is represented by the general formula (G1-2): And in the general formula (G1-2), A 1 and A 2 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 Contains two or more nitrogen atoms.

9. The light emitting device according to claim 1, The heteroaromatic rings are all π-electron-deficient heteroaromatic rings.

10. The light emitting device according to claim 1, The heteroaromatic ring includes at least one of a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring and a triazole ring.

11. The light emitting device according to claim 1, wherein at least one of the heteroaromatic rings included in the second organic compound includes a diazine ring or a triazine ring, The diazine ring is one of a pyrazine ring, a pyrimidine ring and a pyridazine ring.

12. The light emitting device according to claim 1, The heteroaromatic ring included in the second organic compound includes three or more pyridine rings in total.

13. The light emitting device according to claim 1, The first organic compound has an electron-donating group.

14. The light emitting device according to claim 13, The electron-donating group is at least one of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group and a heterocyclic amino group.

15. The light emitting device according to claim 1, The acidity coefficient pK of the first organic compound is a 8 or above.

16. The light emitting device according to claim 1, The first organic compound includes a phenanthroline ring.

17. The light emitting device according to claim 1, The glass transition temperature of the second organic compound is T g Above 100°C.

18. The light emitting device according to claim 1, The LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound.

19. The light emitting device according to claim 1, wherein the metal belongs to Group 1, Group 3, Group 11 or Group 13 of the Periodic Table of Elements.

20. The light emitting device according to claim 1, The electron injection layer is a mixture of the metal, the second organic compound, and the first organic compound.

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