Light-emitting devices

Abstract

To provide a light-emitting device with excellent characteristics. [Solution] An organic compound layer is provided between a pair of electrodes, the organic compound layer has a light-emitting layer and a first layer in contact with the light-emitting layer, the light-emitting layer has a first organic compound, a second organic compound and a fluorescent light-emitting substance, one or both of the first organic compound and the second organic compound have one or more deuterium atoms, the first layer has a third organic compound, and the third organic compound has one or more deuterium atoms.

Description

[Technical Field]

[0001] One aspect of the present invention relates to organic compounds, organic semiconductor elements, light-emitting devices, light-receiving devices, photodiode sensors, display modules, lighting modules, display devices, electronic equipment, lighting devices, and electronic devices. However, one aspect of the present invention is not limited to the above-mentioned technical fields. One aspect of the present invention disclosed herein relates to a product, a method, or a method of manufacture. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. More specifically, one example of a technical field of one aspect of the present invention disclosed herein is a semiconductor device, a display device, a liquid crystal display device, a lighting device, a power storage device, a memory device, an imaging device, a method of driving them, or a method of manufacturing them. [Background technology]

[0002] The practical application of organic electroluminescent devices (organic EL elements), such as light-emitting devices, light-receiving devices, and light-receiving / light-receiving devices, which utilize electroluminescence using organic compounds, is progressing.

[0003] For example, the basic configuration of a light-emitting device is one in which an organic compound layer (EL layer) containing a light-emitting material is sandwiched between a pair of electrodes. By applying a voltage to this device, carriers are injected, and by utilizing the recombination energy of these carriers, light emission can be obtained from the light-emitting material.

[0004] Furthermore, the basic configuration of a photodetector consists of an organic compound layer (active layer) containing a photoelectric conversion material sandwiched between a pair of electrodes. This device absorbs light energy and generates carriers, thereby obtaining electrons from the photoelectric conversion material.

[0005] For example, a functional panel is known in which pixels provided in the display area are equipped with light-emitting elements (light-emitting devices) and photoelectric conversion elements (light-receiving devices) (Patent Document 1).

[0006] Furthermore, while the characteristics of organic EL devices have improved remarkably, they are still insufficient to meet the high demands for all characteristics, including efficiency and durability. For example, a technology has been disclosed in which hydrogen atoms in the host material are replaced with deuterium atoms (deuteration) (Patent Document 2).

[0007] Furthermore, research and development are underway to find organic EL elements with even better characteristics (see, for example, Non-Patent Document 1). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] WO2020 / 152556 [Patent Document 2] Special table number 2013-503860 [Non-patent literature]

[0009] [Non-Patent Document 1] Hiroshi Noguchi, et al., "Orientational Polarization Phenomena of Polar Molecules and Interface Properties of Organic Thin Film Devices," Journal of the Vacuum Society of Japan, 2015, Vol. 58, No. 3. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] One aspect of the present invention aims to provide a novel light-emitting device. Another aspect of the present invention aims to provide a light-emitting device with high luminous efficiency and good reliability.

[0011] One aspect of the present invention aims to provide an organic EL device with a long operating life. Another aspect of the present invention aims to provide a novel organic EL device. Another aspect of the present invention aims to reduce the manufacturing cost of an organic EL device. Another aspect of the present invention aims to provide a light-emitting device, electronic device, or lighting device with low power consumption.

[0012] Furthermore, the description of these problems does not preclude the existence of other problems. Also, one aspect of the present invention does not need to solve all of these problems. Other problems will naturally become clear from the description in the specification, drawings, claims, etc., and it is possible to extract other problems from the description in the specification, drawings, claims, etc. [Means for solving the problem]

[0013] One aspect of the present invention provides an organic compound layer between a pair of electrodes, the organic compound layer having a light-emitting layer and a first layer in contact with the light-emitting layer, the light-emitting layer having a first organic compound, a second organic compound and a fluorescent material, one or both of the first organic compound and the second organic compound having one or more deuterium atoms, the first layer having a third organic compound, and the third organic compound having one or more deuterium atoms.

[0014] One aspect of the present invention provides a pair of electrodes with an organic compound layer between them, the organic compound layer having a light-emitting layer and a first layer in contact with the light-emitting layer, the light-emitting layer having a first organic compound, a second organic compound and a light-emitting substance, the second organic compound being an aromatic compound consisting of an aromatic hydrocarbon, one or both of the first organic compound and the second organic compound having one or more deuterium atoms, the first layer having a third organic compound, and the third organic compound having one or more deuterium atoms.

[0015] One aspect of the present invention provides an organic compound layer between a pair of electrodes, the organic compound layer having a light-emitting layer and a first layer in contact with the light-emitting layer, the light-emitting layer having a first organic compound, a second organic compound and a light-emitting substance, the first organic compound being an organic compound having a heteroaromatic ring, one or both of the first and second organic compounds having one or more deuterium atoms, the first layer having a third organic compound, the third organic compound being a compound having an aromatic amine skeleton and the third organic compound having one or more deuterium atoms.

[0016] In one embodiment above, the luminescent substance is a fluorescent substance. Also in one embodiment above, the first organic compound and the second organic compound each have one or more deuterium atoms. In one embodiment above, either the first organic compound or the second organic compound is a compound having an anthracene skeleton in its molecular structure. In one embodiment above, the first organic compound and the second organic compound are compounds having an anthracene skeleton in their molecular structure. In one embodiment above, the third organic compound is an aromatic amine compound having a heteroaromatic ring.

[0017] One aspect of the present invention provides an organic compound layer between a pair of electrodes, the organic compound layer having a light-emitting layer and a first layer in contact with the light-emitting layer, the light-emitting layer having a first organic compound, a second organic compound and a light-emitting substance, the first organic compound being an organic compound having a heteroaromatic ring containing anthracene, the second organic compound being an organic compound having a heteroaromatic ring containing anthracene, the first organic compound and the second organic compound having different molecular structures, one or both of the first organic compound and the second organic compound having one or more deuterium atoms, the first layer having a third organic compound, and the third organic compound having one or more deuterium atoms.

[0018] One aspect of the present invention is a light-emitting device having an organic compound layer between a pair of electrodes, the organic compound layer having a light-emitting layer and a first layer in contact with the light-emitting layer, the light-emitting layer having a first organic compound, a second organic compound and a light-emitting substance, the first organic compound being an aromatic compound consisting of an aromatic hydrocarbon having anthracene, the second organic compound being an aromatic compound consisting of an aromatic hydrocarbon having anthracene, the first organic compound and the second organic compound having different molecular structures, one or both of the first organic compound and the second organic compound having one or more deuterium atoms, and the first layer having a third organic compound, the third organic compound having one or more deuterium atoms.

[0019] One aspect of the present invention provides an organic compound layer between a pair of electrodes, the organic compound layer having a light-emitting layer and a first layer in contact with the light-emitting layer, the light-emitting layer having a first organic compound, a second organic compound and a light-emitting substance, the first organic compound being represented by the following general formula (G1), the second organic compound being represented by the following general formula (G2), one or both of the first organic compound and the second organic compound having one or more deuterium atoms, the first layer having a third organic compound, and the third organic compound having one or more deuterium atoms.

[0020] [ka]

[0021] Note that in the above formula, R 1 ~R 8 Each independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 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, a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, or a cyano group, Ar 1 and Ar 2 Each of these independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 1 to 30 carbon atoms, Ar 3 and Ar 4each independently represents 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 Ar 3 and Ar 4 one of which is a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. n and m each independently represent an integer of 0 to 4.

[0022]

Chemical Formula

[0023] In the above formula, R 11 to R 18 each independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 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 cyano group, and Ar 11 and Ar 12 each independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, and Ar 13 and Ar 14 each independently represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. p and q each independently represent an integer of 0 to 4.

[0024] [[ID=A32]]Alternatively, another aspect of the present invention is an electronic device having the above light-emitting device or the above light-receiving device, and a sensor, an operation button, a speaker, or a microphone.

[0025] Alternatively, another aspect of the present invention is a lighting device having the above light-emitting device or the above light-receiving device, and a housing.

Advantages of the Invention

[0026] <B According to one aspect of the present invention, a novel light-emitting device can be provided. Further, according to one aspect of the present invention, a light-emitting device having high luminous efficiency and good reliability can be provided.

[0027] Furthermore, according to one aspect of the present invention, a novel organic EL device can be provided. Furthermore, according to one aspect of the present invention, an organic EL device with a long operating life can be provided. Furthermore, according to one aspect of the present invention, the manufacturing cost of the organic EL device can be reduced. Furthermore, according to one aspect of the present invention, a light-emitting device, electronic device, or lighting device with low power consumption can be provided.

[0028] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects will naturally become apparent from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims. [Brief explanation of the drawing]

[0029] [Figure 1] Figures 1(A) and 1(B) are schematic diagrams of light-emitting devices. [Figure 2] Figure 2 shows the capacitance-voltage characteristics of the measuring device 1. [Figure 3] Figure 3 shows the current density-voltage characteristics of the measuring device 1. [Figure 4] Figures 4(A) through 4(E) illustrate the configuration of the light-emitting device. [Figure 5] Figures 5(A) and 5(B) are a top view and a cross-sectional view of the light-emitting device. [Figure 6] Figures 6(A) to 6(G) are top views showing examples of pixel configurations. [Figure 7] Figures 7(A) to 7(I) are top views showing examples of pixel configurations. [Figure 8] Figures 8(A) and 8(B) are perspective views showing example configurations of display modules. [Figure 9] Figures 9(A) and 9(B) are cross-sectional views showing examples of the configuration of a display device. [Figure 10] Figure 10 is a perspective view showing an example of a display device configuration. [Figure 11] Figure 11 is a cross-sectional view showing an example of the configuration of a display device. [Figure 12] Figure 12 is a cross-sectional view showing an example of the configuration of a display device. [Figure 13] Figure 13(A) is a cross-sectional view showing an example of the configuration of a display device, and Figures 13(B) and 13(C) are top views showing an example of the configuration of a display device. [Figure 14] Figure 14 is a cross-sectional view showing an example of the configuration of a display device. [Figure 15] Figure 15(A) is a cross-sectional view showing an example of the configuration of a display device, and Figures 15(B) and 15(C) are top views showing an example of the configuration of a display device. [Figure 16] Figures 16(A) to 16(D) show examples of electronic devices. [Figure 17] Figures 17(A) through 17(F) show examples of electronic devices. [Figure 18] Figures 18(A) to 18(G) show examples of electronic devices. [Figure 19] Figure 19 shows the device structure of light-emitting devices 1A to 1D. [Figure 20] Figure 20 shows the luminance-current density characteristics of light-emitting devices 1A to 1D. [Figure 21] Figure 21 shows the luminance-voltage characteristics of light-emitting devices 1A to 1D. [Figure 22] Figure 22 shows the current efficiency-luminance characteristics of light-emitting devices 1A to 1D. [Figure 23] Figure 23 shows the current density-voltage characteristics of light-emitting devices 1A to 1D. [Figure 24] Figure 24 shows the power efficiency-luminance characteristics of light-emitting devices 1A to 1D. [Figure 25] Figure 25 shows the external quantum efficiency-luminance characteristics of light-emitting devices 1A to 1D. [Figure 26]Figure 26 shows the electroluminescence spectra of light-emitting devices 1A to 1D. [Figure 27] Figure 27 shows the normalized brightness time-dependent characteristics of light-emitting devices 1A to 1D. [Figure 28] Figure 28 shows the luminance-current density characteristics of light-emitting devices 2A to 2D. [Figure 29] Figure 29 shows the luminance-voltage characteristics of light-emitting devices 2A to 2D. [Figure 30] Figure 30 shows the current efficiency-luminance characteristics of light-emitting devices 2A to 2D. [Figure 31] Figure 31 shows the current density-voltage characteristics of light-emitting devices 2A to 2D. [Figure 32] Figure 32 shows the power efficiency-luminance characteristics of light-emitting devices 2A to 2D. [Figure 33] Figure 33 shows the external quantum efficiency-luminance characteristics of light-emitting devices 2A to 2D. [Figure 34] Figure 34 shows the electroluminescence spectra of light-emitting devices 2A to 2D. [Figure 35] Figure 35 shows the normalized brightness time-varying characteristics of light-emitting devices 2A to 2D. [Modes for carrying out the invention]

[0030] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the following description, and its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention should not be interpreted as being limited to the contents of the embodiments shown below.

[0031] In this specification, "deuterated organic compound," "deuterated compound," "deuterated compound," or "organic compound containing deuterium" refers to an organic compound in which, when focusing on the hydrogen (including deuterium) at a specific position in the organic compound, the proportion of that hydrogen (including deuterium) that is deuterium is greater than the natural abundance of deuterium. This proportion is preferably sufficiently greater than the natural abundance. In this case, "sufficiently" means, for example, that 7.5% or more of the hydrogen (including deuterium) is deuterated. The deuteration of an organic compound can be confirmed by methods such as NMR and mass spectrometry.

[0032] Please note that the positions, sizes, and ranges of each component shown in the drawings may not represent their actual positions, sizes, and ranges for the sake of ease of understanding. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and ranges disclosed in the drawings.

[0033] Furthermore, in this specification and other documents, when describing the structure of the invention using drawings, reference numerals that refer to the same thing will be used consistently across different drawings.

[0034] Furthermore, in this specification, terms representing "layers" or "films," such as "hole transport layer," "light-emitting layer," "insulating layer," "semiconductor layer," or "semiconductor film," may be simply referred to as "layer" or "film." Ordinal numbers may also be used. In addition, the words "film" and "layer" can be interchanged depending on the circumstances or situation. For example, "hole transport layer" can be referred to as "layer," "film," or "first layer." Similarly, anodes or cathodes may be simply referred to as "electrodes," or they may be referred to using ordinal numbers, such as "first electrode."

[0035] Furthermore, in this specification, ordinal numbers such as "first," "second," etc., are added to avoid confusion of constituent elements and do not limit the number of constituent elements or the order of constituent elements (e.g., layering order or process order). Also, even if an ordinal number is not used for a term in this specification, an ordinal number may be used in the claims to avoid confusion of constituent elements. Even if an ordinal number is used for a term in this specification, a different ordinal number may be used in the claims. Even if an ordinal number is used for a term in this specification, the ordinal number may be omitted in the claims.

[0036] (Embodiment 1) This embodiment describes a light-emitting device according to one aspect of the present invention, in which a plurality of organic compounds, including an organic compound containing deuterium, are used as a host material for the light-emitting layer and as a layer in contact with the light-emitting layer.

[0037] <Example of light-emitting device configuration> Figure 1(A) is a schematic cross-sectional view of a light-emitting device 10 according to one embodiment of the present invention. The light-emitting device 10 has a pair of electrodes (a first electrode 101 and a second electrode 102) and an organic compound layer 103 provided between the pair of electrodes. The organic compound layer 103 has at least a light-emitting layer 113. In this embodiment 1, the organic compound layer 103 also has a hole transport layer 112.

[0038] Furthermore, the organic compound layer 103 shown in Figure 1(A) 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, in addition to the light-emitting layer 113. Each layer may be a single layer or a configuration in which multiple layers are stacked.

[0039] In this embodiment, the first electrode 101 is described as the anode and the second electrode 102 as the cathode, but the configuration of the light-emitting device 10 is not limited to this. In other words, the first electrode 101 may be the cathode and the second electrode 102 as the anode, and the stacking order of the layers between the electrodes may be reversed. That is, the stacking order from the anode side may be the hole injection layer 111, the hole transport layer 112, the light-emitting layer 113, the electron transport layer 114, and the electron injection layer 115.

[0040] The configuration of the organic compound layer 103 is not limited to the configuration shown in Figure 1(A), and may include at least one selected from the hole injection layer 111, hole transport layer 112, electron transport layer 114, and electron injection layer 115. Alternatively, the organic compound layer 103 may include a functional layer that has functions such as reducing the hole or electron injection barrier, improving hole or electron transport, inhibiting hole or electron transport, or suppressing quenching by electrodes. Each functional layer may be a single layer or a configuration in which multiple layers are stacked.

[0041] Figure 1(B) is a schematic cross-sectional view showing an example of the light-emitting layer 113 shown in Figure 1(A). The light-emitting layer 113 shown in Figure 1(B) comprises two types of host materials 118 (organic compound 118_1 and organic compound 118_2) and a guest material 119 (luminescent substance).

[0042] As the guest material 119, it is preferable to use a substance that emits fluorescence (hereinafter also referred to as a fluorescent compound) among luminescent organic compounds. In particular, by using a fluorescent compound as the luminescent material for blue devices, it is possible to provide a light-emitting device with good reliability.

[0043] Furthermore, in the light-emitting layer 113, the host material 118 is present in the largest amount by weight, and the guest material 119 is dispersed within the host material 118. When a fluorescent compound is used as the guest material, it is preferable that the lowest triplet excitation energy level (T1 level) of the host material 118 in the light-emitting layer 113 is lower than the T1 level of the guest material 119 in the light-emitting layer 113, because this increases the proportion of delayed fluorescence components due to TTA (Triplet-Triplet Annihilation) and improves the luminescence efficiency.

[0044] In one embodiment of the present invention, the host material 118 comprises at least two organic compounds, represented by organic compound 118_1 and organic compound 118_2. Furthermore, the host material 118 of the light-emitting layer 113 (organic compound 118_1 and organic compound 118_2) comprises at least one deuterium atom. In other words, at least one, preferably both, of organic compound 118_1 and organic compound 118_2 is a compound containing deuterium.

[0045] Furthermore, in one aspect of the present invention, a compound containing deuterium is used in the layer in contact with the light-emitting layer 113, specifically the hole transport layer 112. When the hole transport layer 112 is constructed by laminating multiple layers, it is preferable to use a compound containing deuterium in the layer in contact with the light-emitting layer 113.

[0046] By mixing two different organic compounds, 118_1 and 118_2, as the host material 118, the film quality is stabilized and heat resistance is improved when a film is formed. Furthermore, by using a deuterated compound as the host material 118, a highly reliable light-emitting device can be obtained that achieves high luminescence efficiency while suppressing degradation.

[0047] Furthermore, by using a compound containing deuterium in the layer in contact with the light-emitting layer 113 (for example, the hole transport layer 112), the stability of the material in contact with the light-emitting layer 113 with respect to holes or electrons is increased, making it possible to obtain a reliable light-emitting element.

[0048] Here, depending on the configuration of the light-emitting layer 113 or the electron transport layer 114 as described above, the light-emitting device may experience an excess of electrons. An excess of electrons is a situation in which the carrier recombination region in the light-emitting layer 113 is biased towards the hole transport layer 112 and becomes narrower. This situation is advantageous from the standpoint of optical interference, and therefore the light-emitting efficiency can be increased. On the other hand, the increased exciton density in the light-emitting layer 113, or the ease with which electrons reach the hole transport layer 112, tends to accelerate the degradation of the light-emitting device.

[0049] The inventors have discovered that, in light-emitting devices under specific conditions of electron excess, using a deuterated compound in the hole transport layer 112 can achieve high luminescence efficiency while suppressing degradation, resulting in a highly reliable light-emitting device. Further details are provided below.

[0050] First, in the light-emitting layer 113, if the Highest Occupied Molecular Orbital (HOMO) level of the guest material 119 is higher than the HOMO level of the host material 118, holes are trapped in the guest material 119. In such a light-emitting layer 113, injected holes are trapped on the anode side of the light-emitting layer and are not easily moved, while electrons flow in from the cathode side, making it easy for electron excess to occur as described above. Therefore, one aspect of the present invention is a configuration in which a deuterated compound is used in the light-emitting layer 113, or in a layer such as a hole transport layer 112 provided near the light-emitting layer 113, when the HOMO level of the guest material 119 is higher than the HOMO level of the host material 118. Since the deuterated compound has increased stability in the excited state or in the state in which carriers are retained, applying it to the hole transport layer 112 in an electron-excess device can improve the reliability of the light-emitting device. In particular, using deuterated compounds in both the light-emitting layer 113 and the hole transport layer 112 makes the effect of improving reliability even more pronounced.

[0051] In this configuration, if the difference between the HOMO levels of the guest material 119 and the host material 118 is greater than 0.30 eV, particularly if it is 0.35 eV or greater, or 0.40 eV or greater, high luminescence efficiency can be expected in the light-emitting layer 113, but the hole trapping ability becomes very large. As a result, there is an excess supply of electrons, and the degradation of compounds used in layers close to the light-emitting layer 113, such as the hole transport layer 112, may become greater. In this case, a highly reliable light-emitting device can be provided by using a deuterated compound in the hole transport layer 112. On the other hand, if the hole trapping ability is too strong, the number of electrons reaching the hole transport layer 112 increases, which can reduce the exciton generation rate in the light-emitting layer and impair the luminescence efficiency. Therefore, the difference between the HOMO levels of the guest material 119 and the host material 118 is preferably less than 0.90 eV, more preferably 0.70 eV or less, and even more preferably 0.50 eV or less. This configuration allows us to provide a highly efficient and reliable light-emitting device.

[0052] The lowest unoccupied molecular orbital (LUMO) level and HOMO level of a material can be derived from its electrochemical properties (reduction potential and oxidation potential). While cyclic voltammetry (CV) or differential pulsed voltammetry (DPV) can be used to measure these electrochemical properties, it is preferable to compare values ​​estimated using the same measurement method when comparing values ​​between different compounds. Furthermore, the LUMO or HOMO level can also be derived by photoelectron spectroscopy, optical absorption spectroscopy, or inverse photoelectron spectroscopy. However, since the apparent end of the optical absorption spectrum does not necessarily reflect the HOMO-LUMO gap, it is preferable to use the aforementioned electrochemical properties when estimating the LUMO or HOMO level.

[0053] The above describes the case where the light-emitting layer 113 has hole-trapping properties, but there are other configurations in which light-emitting devices are prone to electron excess. For example, if the electron mobility of the host material 118 in the light-emitting layer 113 is high, the light-emitting device is prone to electron excess. Therefore, when the square root of the electric field strength [V / cm] is 600, the electron mobility is 1 × 10⁻⁶. -7 [cm 2 In the case where the host material 118 has a value of [Vs] or higher, the hole transport layer 112 also has a deuterated compound, which is one aspect of the present invention.

[0054] Furthermore, when a compound having four or more fused heteroaromatic rings in its molecular structure is used as the guest material 119, the guest material 119 readily accepts and transports electrons, so while high luminescence efficiency can be expected when used in a light-emitting device, it is prone to electron excess. That is, because electrons can easily reach the hole transport layer, the compound used in the layer in contact with the light-emitting layer, such as the hole transport layer, may degrade. Therefore, when the light-emitting layer 113 has such a configuration, using a deuterated compound in the layer in contact with the light-emitting layer or in the hole transport layer suppresses the degradation of the hole transport layer by electrons, and this configuration is also one aspect of the present invention. Moreover, by using this configuration, high luminescence efficiency can be achieved while suppressing degradation over time due to the operation of the light-emitting device.

[0055] Furthermore, if the electron transport layer 114 has a stacked structure of two or more layers, the light-emitting device may experience an excess of electrons. Specifically, this occurs when the electron transport layer 114 has at least a first electron transport layer and a second electron transport layer, with the first electron transport layer being provided between the light-emitting layer 113 and the second electron transport layer. In this case, it is particularly preferable from the viewpoint of providing a device with a low driving voltage that the first electron transport layer contains a compound having a diazine skeleton or triazine skeleton, and the second electron transport layer contains a compound having a phenanthroline skeleton. While this configuration allows for a device with low power consumption, on the other hand, such a configuration has very high electron transport properties, making the light-emitting device prone to an excess of electrons. Therefore, in a light-emitting device in which the electron transport layer 114 has such a configuration, using a deuterated compound in the hole transport layer 112 is also one aspect of the present invention, which can achieve both low power consumption and high reliability.

[0056] Furthermore, when the difference between the LUMO level of the host material 118 of the light-emitting layer 113 and the LUMO level of the material used in the electron transport layer 114 in contact with the light-emitting layer is small, the electron injection from the electron transport layer 114 to the light-emitting layer 113 becomes high, which can easily lead to an excess of electrons. In particular, when the difference between the LUMO level of the host material 118 of the light-emitting layer 113 and the LUMO level of the material used in the electron transport layer 114 in contact with the light-emitting layer 113 is 0.25 eV or less, the electron injection becomes very high. Therefore, in a light-emitting device with such a configuration, by using a deuterium compound in the hole transport layer 112, high luminous efficiency can be obtained while suppressing brightness degradation due to the operation of the light-emitting device.

[0057] In this embodiment 1, if the hole transport layer 112 has a structure in which two or more layers with different configurations are stacked, it is particularly preferable to use a deuterated compound in the layer in contact with the light-emitting layer. This is because, in the hole transport layer 112 of an electron-excessive light-emitting device as described above, the layer of the hole transport layer 112 that is in contact with the light-emitting layer is the one that is most susceptible to degradation by electrons. While it is particularly preferable to use it in the layer in contact with the light-emitting layer, its use is not limited to this. Since deuterated compounds stabilize the bonds and suppress degradation, they also improve the reliability of the device even when used in a layer that is not in contact with the light-emitting layer. In other words, a deuterated compound can be used as a layer (single-layer or stacked hole transport layer 112) provided between the light-emitting layer and the anode. Furthermore, when the hole transport layer 112 is stacked, a deuterated compound can be used in at least one or both of the layer in contact with the light-emitting layer and the layer that is not in contact with the light-emitting layer, and as described above, it is particularly preferable to use it in the layer in contact with the light-emitting layer.

[0058] Furthermore, it is preferable that the material used for the hole transport layer 112 is different from the material used for the light-emitting layer 113. If the same material is used for both the hole transport layer 112 and the light-emitting layer 113, electrons injected into the light-emitting layer can easily move to adjacent hole transport layers 112, which may lead to a decrease in luminescence efficiency or degradation of the hole transport layer 112. However, by using different materials for the hole transport layer 112 and the light-emitting layer 113, it is possible to prevent holes and electrons from moving to the hole transport layer 112, thereby increasing luminescence efficiency. In addition, by using different materials for the hole transport layer 112 and the light-emitting layer 113, it is possible to provide a light-emitting device with good carrier balance and high efficiency.

[0059] Aromatic amine compounds are preferred as the deuterated compounds used in the hole transport layer 112. In particular, compounds having only one triarylamine skeleton in their molecular structure are preferred. Such compounds tend to have a deeper HOMO compared to compounds like diamines or triamines, making it easier to inject holes into the light-emitting layer, and thus suitable for electron-overload devices from a reliability standpoint. Furthermore, compounds like diamines or triamines tend to have high deposition temperatures, making them susceptible to thermal decomposition during deposition. If compound decomposition occurs, the purity of the deposited film decreases, potentially reducing the reliability of the light-emitting device. On the other hand, compounds having only one triarylamine skeleton tend to have deposition temperatures sufficiently lower than the decomposition temperature of the compound, allowing for the acquisition of a highly pure deposited film and providing a reliable light-emitting device.

[0060] Therefore, for example, automotive displays require performance that can withstand prolonged exposure to high temperatures, making the light-emitting device according to one embodiment of the present invention suitable for use. Furthermore, the configuration of the light-emitting layer according to one embodiment of the present invention can suppress degradation due to the heating process for removing moisture in processing using photolithography, thereby improving design flexibility.

[0061] Furthermore, it is preferable that the host material 118 includes an organic compound having a heteroaromatic ring. By using organic compounds having different heteroaromatic rings for organic compound 118_1 and organic compound 118_2, a light-emitting device with a low driving voltage and low power consumption can be provided. In addition, this configuration makes it easier to maintain carrier balance, thus providing a highly efficient light-emitting device.

[0062] Furthermore, it is preferable that the host material 118 includes an aromatic compound consisting of an aromatic hydrocarbon. By using different aromatic compounds consisting of aromatic hydrocarbons for organic compound 118_1 and organic compound 118_2, a highly reliable light-emitting device can be provided.

[0063] Furthermore, for example, organic compound 118_1 may be an organic compound having a heteroaromatic ring, and organic compound 118_2 may be an aromatic compound consisting of aromatic hydrocarbons. Having an organic compound having a heteroaromatic ring makes it possible to maintain carrier balance, thereby achieving high efficiency and low power consumption, and having an aromatic compound consisting of aromatic hydrocarbons provides a light-emitting device with good reliability.

[0064] Furthermore, when organic compound 118_1 is an organic compound having an anthracene skeleton and a heteroaromatic ring, and organic compound 118_2 is an aromatic compound consisting of an aromatic hydrocarbon having an anthracene skeleton, the carrier balance of the light-emitting layer is improved, making it possible to provide a device with high luminescence efficiency, which is preferable. In particular, when the skeleton on which the orbitals of the LUMO level responsible for electron transport are distributed is an anthracene skeleton, it is preferable because high electron injection into the light-emitting layer and high electron transport of the light-emitting layer can be achieved.

[0065] Furthermore, when an aromatic compound consisting of aromatic hydrocarbons is used as the host material 118, the electron injection properties into the light-emitting layer and the electron transport properties of the light-emitting layer are improved. However, if excessive electron injection into the light-emitting layer occurs, the carrier balance of the light-emitting layer may be disrupted, and the recombination region may be extremely biased towards the anode side of the light-emitting layer. It is preferable to use both an organic compound having a heteroaromatic ring and an aromatic compound consisting of aromatic hydrocarbons in the light-emitting layer because the hole injection properties into the light-emitting layer are improved and the balance of holes and electrons in the light-emitting layer is improved. If the HOMO level of the organic compound having a heteroaromatic ring is lower than that of the aromatic compound consisting of aromatic hydrocarbons, the electron mobility of the organic compound having a heteroaromatic ring is suppressed, electron injection into the light-emitting layer is suppressed, and the carrier balance of the light-emitting layer is improved. On the other hand, if the HOMO level of the organic compound having a heteroaromatic ring is higher than that of the aromatic compound consisting of aromatic hydrocarbons, the hole mobility of the organic compound having a heteroaromatic ring is increased, so hole injection into the light-emitting layer is increased and the carrier balance of the light-emitting layer is improved.

[0066] Furthermore, when using an organic compound having a heteroaromatic ring for organic compound 118_1 and an aromatic compound consisting of an aromatic hydrocarbon for organic compound 118_2, it is preferable because the organic compound 118_1, which is an organic compound having a heteroaromatic ring, contains deuterium, thus improving reliability compared to an aromatic compound consisting of an aromatic hydrocarbon, which has high reliability.

[0067] On the other hand, when organic compound 118_1, which is an aromatic compound composed of aromatic hydrocarbons, contains deuterium, the carbon-deuterium bond in the excited state is more stable than the carbon-practicum bond in the excited state, and the reaction that produces degraded products from the excited state is suppressed, thus improving reliability.

[0068] Furthermore, when both organic compound 118_1, which is an organic compound having a heteroaromatic ring, and organic compound 118_2, which is an aromatic compound consisting of aromatic hydrocarbons, are used, the carrier balance of the light-emitting layer improves, the exciton density increases, and degradation tends to accelerate. However, when both organic compound 118_1, which is an organic compound having a heteroaromatic ring, and organic compound 118_2, which is an aromatic compound consisting of aromatic hydrocarbons, contain deuterium, degradation can be sufficiently suppressed even when the exciton density is high, resulting in a synergistic effect and a dramatic improvement in reliability, which is preferable.

[0069] Furthermore, it is preferable to use an aromatic amine compound having a heteroaromatic ring containing deuterium as the layer in contact with the light-emitting layer 113 (hole transport layer 112). With this configuration, both electrons and holes are more easily injected into the light-emitting layer, resulting in a better carrier balance and enabling the acquisition of a device with high luminous efficiency at a low driving voltage. Alternatively, with this configuration, the mobility of electrons and holes in the light-emitting layer is increased, enabling the acquisition of a device with good carrier balance and high luminous efficiency at a low driving voltage.

[0070] <Examples of organic compounds that can be used in the layer in contact with the light-emitting layer 113> As an organic compound that can be used in a layer in contact with the light-emitting layer of a light-emitting device according to one aspect of the present invention, for example, the following organic compounds can be used. In particular, when a layer is provided on the anode side of the light-emitting layer 113, it is preferable to use an organic compound that has hole-transporting properties. Specifically, examples include, but are not limited to, the compounds shown in structural formulas (100) to (178) below.

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] <Examples of organic compounds that can be used in host material 118> For example, the following organic compounds can be used as the host material 118 that can be used in a light-emitting device according to one aspect of the present invention. Note that if the organic compound represented by general formula (G1) and the organic compound represented by general formula (G2) have deuterium, R x A substituent represented by (x is an integer), and Ar y Any of the hydrogen atoms in the substituent represented by (where y is an integer) may be deuterium.

[0082] Examples of organic compounds containing heteroaromatic rings For example, an organic compound represented by general formula (G1) can be used as the host material 118.

[0083] [ka]

[0084] In the above formula, R 1 ~R 8 Each of these independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 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, a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, or a cyano group. 1 and Ar 2 Each of these independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 1 to 30 carbon atoms, Ar 3 and Ar 4Each of these independently represents 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, Ar 3 and Ar 4 One of these is a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. n and m each independently represent an integer from 0 to 4. Note that all hydrogen atoms in general formula (G1) may independently be light hydrogen or deuterium.

[0085] Examples of aromatic compounds consisting of aromatic hydrocarbons Furthermore, for example, an organic compound represented by general formula (G2) can be used as the host material 118.

[0086] [ka]

[0087] In the above formula, R 11 ~R 18 Each independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 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 cyano group, Ar 11 and Ar 12 Each of these independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, and Ar 13 and Ar 14 Each of the following independently represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. p and q each independently represent an integer from 0 to 4. Note that all hydrogen atoms in general formula (G2) may independently be light hydrogen or deuterium.

[0088] In the following, in the general formula (G1), R x (x is an integer) or Ar y Specific examples of substituents represented by (y is an integer) are shown below.

[0089] Examples of linear or branched alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, neopentyl, hexyl, isohexyl, 3-methylpentyl, 2-methylpentyl, 2-ethylbutyl, 1,2-dimethylbutyl, 2,3-dimethylbutyl, and 1-ethylpropyl.

[0090] Examples of cycloalkyl groups having 3 to 10 carbon atoms include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, bicyclo[2,2,2]octyl group, decahydronaphthyl group, and adamantyl group.

[0091] Examples of aryl groups having 6 to 30 carbon atoms include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, mesityl group, biphenyl-2-yl group (o-biphenyl group), biphenyl-3-yl group (m-biphenyl group), biphenyl-4-yl group (p-biphenyl group), 1-naphthyl group, 2-naphthyl group, phenylnaphthyl group, naphthylphenyl group, terphenyl group, fluorenyl group, 9,9-dimethylfluorenyl group, quaterphenyl group, spirobifluorenyl group, phenanthryl group, anthryl group, binaphthylphenyl group, and fluoranthenyl group.

[0092] Furthermore, if the aryl group has substituents, examples of such substituents include halogens, cyano groups, C1 to C6 alkyl groups, C2 to C6 alkenyl groups, C2 to C6 alkynyl groups, C1 to C6 alkoxy groups, C3 to C10 trialkylsilyl groups, C3 to C10 cycloalkyl groups, phenyl groups, naphthyl groups, phenantrenyl groups, and the like.

[0093] Examples of heteroaryl groups having 1 to 30 carbon atoms include 1,3,5-triazine-2-yl group, 1,2,4-triazine-3-yl group, pyrimidine-4-yl group, pyrazine-2-yl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, carbazolyl group, dibenzofuranyl group, dibenzothiophenyl group, benzonaphthofuranyl group, benzonaphthothiophenyl group, indolocarbazolyl group, benzoflocarbazolyl group, benzothienocarbazolyl group, indenocarbazolyl group, and dibenzocarbazolyl group.

[0094] Furthermore, if the heteroaryl group has substituents, examples of such substituents include C1 to C10 alkyl groups, C3 to C10 cycloalkyl groups, phenyl groups, naphthyl groups, and phenantrenyl groups.

[0095] Examples of arylene groups having 6 to 30 carbon atoms include phenylene group, biphenyl-diyl group, naphthalene-diyl group, fluorene-diyl group, acenaphthene-diyl group, anthracene-diyl group, phenanthrene-diyl group, terphenyl-diyl group, triphenylene-diyl group, phenanthrene-diyl group, tetracenyl group, benzanthracene-diyl group, pyrene-diyl group, and spirobi[9H-fluorene]-diyl group.

[0096] Furthermore, if the arylene group has substituents, examples of such substituents include C1 to C10 alkyl groups, C3 to C10 cycloalkyl groups, phenyl groups, naphthyl groups, and phenantrenyl groups.

[0097] Examples of heteroarylene groups having 1 to 30 carbon atoms include pyrimidine-diyl group, pyrazine-diyl group, pyridazine-diyl group, triazine-diyl group, bipyridine-diyl group, phenanthroline-diyl group, quinoxaline-diyl group, dibenzoquinoxaline-diyl group, quinazoline-diyl group, benzoquinazoline-diyl group, dibenzoquinazoline-diyl group, imidazo-diyl group, triazole-diyl group, and oxadiazole-diyl group. Examples include yl group, benzimidazole-diyl group, phlodiazine-diyl group, benzoflopyrimidine-diyl group, thiophene-diyl group, furan-diyl group, benzothiophene-diyl group, benzofuran-diyl group, dibenzothiophene-diyl group, dibenzofuran-diyl group, benzonaphthothiophene-diyl group, benzonaphthofuran-diyl group, dinaphthothiophene-diyl group, and dinaphthofuran-diyl group.

[0098] Furthermore, if any of the above heteroarylene groups have substituents, examples of substituents include C1 to C4 alkyl groups, C3 to C6 cycloalkyl groups, or phenyl groups, naphthyl groups, and phenantrenyl groups.

[0099] In the following, in the general formula (G2), R x (x is an integer) or Ar y Specific examples of substituents represented by (y is an integer) are shown below.

[0100] Examples of linear or branched alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, neopentyl, hexyl, isohexyl, 3-methylpentyl, 2-methylpentyl, 2-ethylbutyl, 1,2-dimethylbutyl, 2,3-dimethylbutyl, and 1-ethylpropyl.

[0101] Examples of cycloalkyl groups having 3 to 10 carbon atoms include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, bicyclo[2,2,2]octyl group, decahydronaphthyl group, and adamantyl group.

[0102] Examples of aryl groups having 6 to 30 carbon atoms include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, mesityl group, biphenyl-2-yl group (o-biphenyl group), biphenyl-3-yl group (m-biphenyl group), biphenyl-4-yl group (p-biphenyl group), 1-naphthyl group, 2-naphthyl group, phenylnaphthyl group, naphthylphenyl group, terphenyl group, fluorenyl group, 9,9-dimethylfluorenyl group, quaterphenyl group, spirobifluorenyl group, phenanthryl group, anthryl group, binaphthylphenyl group, and fluoranthenyl group.

[0103] Furthermore, if the aryl group has substituents, examples of such substituents include halogens, cyano groups, C1 to C6 alkyl groups, C2 to C6 alkenyl groups, C2 to C6 alkynyl groups, C1 to C6 alkoxy groups, C3 to C10 trialkylsilyl groups, C3 to C10 cycloalkyl groups, phenyl groups, naphthyl groups, phenantrenyl groups, and the like.

[0104] Examples of arylene groups having 6 to 30 carbon atoms include phenylene group, biphenyl-diyl group, naphthalene-diyl group, fluorene-diyl group, acenaphthene-diyl group, anthracene-diyl group, phenanthrene-diyl group, terphenyl-diyl group, triphenylene-diyl group, phenanthrene-diyl group, tetracenyl group, benzanthracene-diyl group, pyrene-diyl group, and spirobi[9H-fluorene]-diyl group.

[0105] Furthermore, if the arylene group has substituents, examples of such substituents include C1 to C10 alkyl groups, C3 to C10 cycloalkyl groups, phenyl groups, naphthyl groups, and phenantrenyl groups.

[0106] <GSP_Slope of each layer in the organic compound layer> Furthermore, the spontaneous orientation polarization (SOP) that occurs in vapor-deposited films of organic compounds such as light-emitting layers will be explained below.

[0107] In vapor-deposited films of organic compounds such as luminescent layers, the permanent electric dipole moments of molecules may be oriented, resulting in spontaneous orientation polarization (SOP). Furthermore, if the spontaneous polarization is biased in the direction of film thickness, a giant surface potential (GSP) may be generated. Since GSP increases proportionally with film thickness, a slope of GSP (GSP_slope) exists as a physical property of the layer. GSP_slope is expressed as ΔV / Δd, where the change in surface potential is ΔV (mV) for a change in film thickness Δd (nm). In other words, GSP_slope is the GSP per unit film thickness. Note that if the surface potential increases with increasing film thickness, it is a positive GSP_slope, while if the surface potential decreases with increasing film thickness, it is a negative GSP_slope.

[0108] Furthermore, when layers with different GSP_slope are stacked, an electric charge is generated at the interface, and this interface charge affects the device characteristics. Therefore, in a light-emitting device, by selecting the materials used for each layer while considering the gradient of the giant surface potential (GSP_slope) of the light-emitting layer 113 and the layers surrounding the light-emitting layer 113, the interface charge can be controlled, thereby improving the luminous efficiency of the light-emitting device or reducing the driving voltage.

[0109] For example, in the case of a light-emitting device with the anode placed on the substrate side (referred to as a forward-stacked device), by configuring the device so that the GSP_slope of the light-emitting layer 113, especially the GSP_slope of the host material 118 which has a large weight ratio, is smaller than the GSP_slope of the hole transport layer 112, hole injection from the hole transport layer 112 to the light-emitting layer 113 is suppressed. Therefore, the light-emitting region can be localized near the interface between the light-emitting layer 113 and the hole transport layer 112, making it possible to create a light-emitting device that effectively utilizes triplet-triplet annihilation (TTA). In other words, in a forward-stacked device, it is possible to improve the luminescence efficiency by effectively utilizing triplet-triplet annihilation. Furthermore, in the case of a forward-stacked device, by configuring the device so that the GSP_slope of the light-emitting layer 113 is larger than the GSP_slope of the hole transport layer 112, hole injection into the light-emitting layer becomes possible, thus allowing for a lower driving voltage for the light-emitting device. To compare GSP_slope, you should compare the GSP_slope of a layer fabricated using the host material with the GSP_slope of a layer fabricated using the hole-transporting material. The method for determining GSP_slope is described below.

[0110] On the other hand, in the case of a light-emitting device in which the cathode is placed on the substrate side (referred to as an inverted stacking device), by configuring the device so that the GSP_slope of the light-emitting layer 113, especially the GSP_slope of the host material 118 which has a large weight ratio, is larger than the GSP_slope of the hole transport layer 112, hole injection from the hole transport layer 112 to the light-emitting layer 113 is suppressed. Therefore, it is possible to localize the light-emitting region near the interface between the light-emitting layer 113 and the hole transport layer 112, and to create a light-emitting device that effectively utilizes triplet-triplet annihilation (TTA). Furthermore, in the case of an inverted stacking device, by configuring the device so that the GSP_slope of the light-emitting layer 113 is smaller than the GSP_slope of the hole transport layer 112, hole injection into the light-emitting layer becomes possible, and thus the driving voltage of the light-emitting device can be lowered.

[0111] To compare GSP_slope, one should compare the GSP_slope of a layer fabricated using a host material with the GSP_slope of a layer fabricated using a hole-transporting material. If multiple types of host materials are mixed in the light-emitting layer, the above-mentioned effect can be obtained if the GSP_slope of a layer fabricated using any one of the host materials is larger or smaller than the GSP_slope of a layer fabricated using a hole-transporting material. More preferably, the GSP_slope of a layer mixed with multiple types of host materials should be compared with the GSP_slope of a layer fabricated using a hole-transporting material. It is also preferable to compare the GSP_slope of each layer fabricated using each of the multiple types of host materials with the GSP_slope of a layer fabricated using a hole-transporting material. In that case, the above effect can be enhanced if all of the GSP_slopes of each layer are larger or smaller than the GSP_slope of the layer fabricated using a hole-transporting material. The method for determining GSP_slope is described below.

[0112] When using multiple types of host materials, the GSP_slope value will differ depending on the molecular structure of the host material used. Specifically, in the case of organic compounds with heteroaromatic rings, the permanent electric dipole moment of the molecule tends to be more easily oriented than that of organic compounds composed of aromatic hydrocarbons, resulting in a larger GSP_slope. In this way, by adjusting the molecular structure, it is possible to adjust the magnitude of GSP_slope and thereby adjust the carrier implantation properties between the light-emitting layer and the hole transport layer.

[0113] <How to find GSP_slope> Here, we will explain how to determine the GSP_slope of a film formed by vacuum deposition of an organic compound.

[0114] First, we will explain how to calculate GSP_slope in a configuration where the carriers accumulating at the interface are holes. The phenomenon in which the surface potential of a deposited film increases in proportion to the film thickness is called giant surface potential, as mentioned above. Generally, the slope when the surface potential of a deposited film measured by Kelvin probe is plotted in the direction of film thickness is discussed as the magnitude of the giant surface potential, i.e., GSP_slope (mV / nm). However, when two different layers are stacked, the charge density (mC / m) accumulated at the interface... 2 By utilizing the fact that ) changes in relation to GSP, we can estimate GSP_slope.

[0115] Non-patent document 1 shows that when organic thin films with different spontaneous polarizations (thin film 1 and thin film 2, where thin film 1 is on the anode side and thin film 2 is on the cathode side, and the anode is located on the substrate side) are stacked and a voltage is applied, the following equation holds true if the carriers accumulated at the interface are holes.

[0116]

number

[0117]

number

[0118] In equation (1), σ if_h Q is the interfacial charge density. if is the interfacial charge, S is the surface area, V is the surface area. i V is the hole injection voltage. bi V is the threshold voltage, d2 is the thickness of thin film 2, and ε2 is the dielectric constant of thin film 2. i , V bi This can be estimated from the capacitance-voltage characteristics of the device. Furthermore, the dielectric constant is the refractive index n. o The square of (wavelength 633 nm) can be used. In this way, V estimated from the capacitance-voltage characteristics i , V bi Then, using the dielectric constant ε2 of thin film 2 calculated from the refractive index, and the film thickness d2 of thin film 2, the interfacial charge density σ is calculated using equation (1). if_hIt is possible to find this.

[0119] Next, in equation (2), σ if_h P is the interfacial charge density. n ε is the spontaneous polarization of a thin film n (where n is 1 or 2) in the direction normal to the substrate. n V is the dielectric constant of the thin film n. n d is the potential of the film surface, n is the thickness of the thin film n. And the potential (V) of the film surface. n ) film thickness (d n The GSP_slope can be calculated from the value obtained by dividing by ). Here, from the above equation (1), the interfacial charge density σ if_h Since this can be determined, the GSP_slope of thin film 1 can be estimated by using a material with a known GSP_slope as thin film 2 and adopting an appropriate dielectric constant.

[0120] Therefore, using tris(8-quinolinolato)aluminum (abbreviated as Alq3), which has a known GSP_slope of 48 (mV / nm), as thin film 2, a measurement device 1 was fabricated and an example of determining the GSP_slope of 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB) is shown below.

[0121] The device structure of measurement device 1 is shown in Table 1. For the anode, indium tin oxide (ITSO) containing silicon or silicon oxide was used. The cathode of measurement device 1, from layer 1_1, was formed by vacuum deposition from the anode side, at room temperature and a deposition rate of 0.2 nm / s to 0.6 nm / s. Deposition was carried out without stopping the deposition process between layers. In measurement device 1, layer 2_1 corresponds to thin film 1, and layer 3_1 corresponds to thin film 2. OCHD-003 is an organic compound with electron acceptor properties.

[0122] When fabricating the measurement device, the deposition rate of each layer is preferably 3 nm / min to 600 nm / min. Furthermore, the film thickness of each layer in the measurement device is preferably 3 nm to 500 nm, and more preferably 50 nm to 300 nm.

[0123] Furthermore, the capacitance-voltage characteristics of the measurement device 1 are shown in Figure 2.

[0124] [Table 1]

[0125] Table 2 shows the Hole injection voltage V of the measuring device 1, which was determined using Figure 2 and equations (1) and (2). i , threshold voltage V bi , interfacial charge density σ if_h , GSP_slope and the refractive index n of the NPB used in the calculation o and the refractive index n of Alq3 o The results are shown. The refractive index was measured using a spectroscopic ellipsometer (M-2000U, manufactured by J.A. Woolam Japan Co., Ltd.).

[0126] [Table 2]

[0127] Furthermore, we fabricated a measurement device 2 with almost the same configuration as measurement device 1, except that the Alq3 film thickness was 80 nm, and confirmed that the hole injection voltage in each device was shifted to a lower voltage than that of measurement device 1. This suggests that in such devices, holes are injected first, and charge accumulates at the interface with Alq3. We also used measurement device 2 to estimate the GSP_slope in the same way as measurement device 1 and confirmed that the same results were obtained.

[0128] Furthermore, the threshold voltage V can be obtained from the capacitance-voltage characteristics. bi If it is difficult to determine, the threshold voltage of the current density-voltage characteristic may be used.

[0129] Figure 3 shows the current density-voltage characteristics of measuring device 1.

[0130] V estimated from current density-voltage characteristics bi The voltage was 2.0V, which was the same value as the one estimated from the capacitance-voltage characteristics.

[0131] In this way, by fabricating a device in which an Alq3 film with a known GSP_slope and a film formed with an organic compound whose GSP_slope is to be determined are stacked, and measuring the capacitance-voltage characteristics, the GSP_slope of the organic compound can be estimated.

[0132] In the above explanation, we described a method for calculating GSP_slope in a configuration where the carriers accumulating at the interface are holes. However, when calculating the GSP_slope of an organic film in a configuration where the carriers accumulating at the interface are electrons, it can be calculated similarly using equations (3) and (4) below. Note that in equations (3) and (4) below, σ if_e This is the interfacial charge density.

[0133]

number

[0134]

number

[0135] It is preferable to select the organic compounds to be used in each layer of the light-emitting device, taking into account the GSP_slope of the vapor-deposited film of the organic compound measured in advance using the measurement method described above.

[0136] In some cases, light-emitting devices use layers co-deposited with multiple types of organic compounds. Since the GSP_slope of a co-deposited layer changes depending on the combination and mixing ratio of the organic compounds, it is ideal to measure the GSP_slope of a layer co-deposited with multiple types of organic compounds to be actually used in a light-emitting device, as well as a film co-deposited with the same combination and mixing ratio of organic compounds, and then select the organic compounds considering this GSP_slope. However, this method requires fabricating different co-deposited films for each combination or mixing ratio of organic compounds and measuring the GSP_slope for each, making the experiments for selecting organic compounds complicated.

[0137] Therefore, in a light-emitting device, if one layer contains multiple types of organic compounds, it is preferable to select the organic compounds by considering the average of the GSP_slope values ​​of the vapor-deposited films of each organic compound, which have been measured in advance, as the GSP_slope of that layer. This makes it relatively easy to select organic compounds while considering GSP_slope.

[0138] However, even if a single layer contains multiple types of organic compounds, if their content differs significantly, the GSP_slope of the vapor-deposited film of the organic compound with the highest content among the multiple organic compounds can be considered the GSP_slope of that layer, and the organic compound can be selected accordingly. For example, if a single layer contains two types of organic compounds, and the content of one organic compound is less than 20% by weight of the total, that organic compound can be judged as a minor component of that layer, and the other, more abundant organic compound can be judged as the main component of that layer, and the GSP_slope of the vapor-deposited film of that main component can be considered the GSP_slope of that layer. Also, if a single layer contains three or four types of organic compounds, and the content of one organic compound is less than 20% by weight of the total, that organic compound can be judged as a minor component of that layer, and the remaining organic compounds can be judged as the main components of that layer, and the average value of the GSP_slope of the vapor-deposited films of each main component can be considered the GSP_slope of that layer.

[0139] <Basic structure of a light-emitting device> The basic structure of the light-emitting device will be explained in more detail below using Figures 4(A) to 4(E). Figure 4(A) shows a light-emitting device with a structure (single structure) having an organic compound layer (also called an EL layer) containing a light-emitting layer between a pair of electrodes. Specifically, it has a structure in which an organic compound layer 103 is sandwiched between the first electrode 101 and the second electrode 102.

[0140] Furthermore, Figure 4(B) shows a light-emitting device with a laminated structure (tandem structure) having multiple (two layers in Figure 4(B)) organic compound layers (103a, 103b) between a pair of electrodes, and a charge generation layer 106 between the organic compound layers. A light-emitting device with a tandem structure can realize a highly efficient light-emitting device without changing the amount of current.

[0141] The charge generation layer 106 has the function of injecting electrons into one organic compound layer (103a or 103b) and holes into the other organic compound layer (103b or 103a) when a potential difference is created between the first electrode 101 and the second electrode 102. Therefore, in Figure 4(B), when a voltage is applied to the first electrode 101 such that the potential is higher than that of the second electrode 102, electrons are injected from the charge generation layer 106 into the organic compound layer 103a and holes are injected into the organic compound layer 103b.

[0142] Furthermore, from the viewpoint of light extraction efficiency, it is preferable that the charge generation layer 106 is transparent to visible light (specifically, the transmittance of visible light to the charge generation layer 106 is 40% or more). In addition, the charge generation layer 106 can function even if its conductivity is lower than that of the first electrode 101 and the second electrode 102.

[0143] Figure 4(C) shows the laminated structure of the organic compound layer 103 of a light-emitting device according to one embodiment of the present invention. In this case, the first electrode 101 functions as an anode and the second electrode 102 functions as a cathode. The organic compound layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115 are sequentially laminated on the first electrode 101. The light-emitting layer 113 may be a configuration in which multiple light-emitting layers with different emission colors are laminated. For example, a light-emitting layer containing a red light-emitting substance, a light-emitting layer containing a green light-emitting substance, and a light-emitting layer containing a blue light-emitting substance may be laminated, or laminated via a layer having a carrier transport material. Alternatively, a combination of a light-emitting layer containing a yellow light-emitting substance and a light-emitting layer containing a blue light-emitting substance may be used. However, the laminated structure of the light-emitting layer 113 is not limited to the above. For example, the light-emitting layer 113 may be configured by stacking multiple light-emitting layers of the same emission color. For example, it may be a structure in which a first light-emitting layer containing a blue light-emitting substance and a second light-emitting layer containing a blue light-emitting substance are stacked, or stacked via a layer having a carrier transport material. In the case of a configuration in which multiple light-emitting layers of the same emission color are stacked, reliability can be increased compared to a single-layer configuration. Also, even when there are multiple light-emitting layers as in the tandem structure shown in Figure 4(B), the layers of the organic compound layer 103 are stacked sequentially from the anode side as described above. Furthermore, when the first electrode 101 is the cathode and the second electrode 102 is the anode, the stacking order of the organic compound layer 103 is reversed. Specifically, on the first electrode 101, which is the cathode, 111 is an electron injection layer, 112 is an electron transport layer, 113 is a light-emitting layer, 114 is a hole transport layer, and 115 is a hole injection layer.

[0144] The light-emitting layers 113 contained within the organic compound layers (103, 103a, 103b) each contain a light-emitting substance and a combination of multiple substances as appropriate, and can be configured to produce fluorescence emission or phosphorescence emission exhibiting a desired emission color. Alternatively, the light-emitting layers 113 may be arranged in a laminated structure with different emission colors. In this case, the light-emitting substance and other substances used in each laminated light-emitting layer may be made of different materials. Furthermore, a configuration may be used in which different emission colors can be obtained from multiple organic compound layers (103a, 103b) as shown in Figure 4(B). In this case as well, the light-emitting substance and other substances used in each light-emitting layer may be made of different materials.

[0145] Furthermore, in a light-emitting device according to one aspect of the present invention, for example, by using a reflective electrode as the first electrode 101 shown in Figure 4(C) and a semi-transparent / semi-reflective electrode as the second electrode 102, and by using a microcavity structure, the light emitted from the light-emitting layer 113 contained in the organic compound layer 103 can be resonated between the two electrodes, thereby strengthening the light emitted from the second electrode 102. Therefore, it is easy to achieve high resolution. In addition, since it is possible to strengthen the light emission intensity in the front direction at a specific wavelength, power consumption can be reduced.

[0146] Furthermore, if the first electrode 101 of the light-emitting device is a reflective electrode consisting of a laminated structure of a reflective conductive material and a translucent conductive material (transparent conductive film), optical adjustment can be performed by controlling the film thickness of the transparent conductive film. Specifically, it is preferable to adjust the optical distance (product of film thickness and refractive index) between the first electrode 101 and the second electrode 102 to be mλ / 2 (where m is an integer of 1 or more) or close to it, with respect to the wavelength λ of light obtained from the light-emitting layer 113.

[0147] Furthermore, in order to amplify the light of a desired wavelength (wavelength: λ) obtained from the light-emitting layer 113, it is preferable to adjust the optical distance from the first electrode 101 to the region of the light-emitting layer 113 where light of the desired wavelength is obtained (light-emitting region), and the optical distance from the second electrode 102 to the region of the light-emitting layer 113 where light of the desired wavelength is obtained (light-emitting region), so that they are (2m'+1)λ / 4 (where m' is an integer of 1 or more) or near that value. The light-emitting region referred to here is the region in the light-emitting layer 113 where holes and electrons recombine.

[0148] By performing such optical adjustments, the spectrum of specific monochromatic light obtained from the light-emitting layer 113 can be narrowed, resulting in emission with good color purity.

[0149] However, in the above case, the optical distance between the first electrode 101 and the second electrode 102 can be precisely defined as the total thickness from the reflective region of the first electrode 101 to the reflective region of the second electrode 102. However, since it is difficult to precisely determine the reflective regions of the first electrode 101 and the second electrode 102, the above effects can be sufficiently obtained by assuming that any position on the first electrode 101 and the second electrode 102 are reflective regions. Furthermore, the optical distance between the first electrode 101 and the light-emitting layer from which light of the desired wavelength can be obtained can be precisely defined as the optical distance between the reflective region of the first electrode 101 and the light-emitting region of the light-emitting layer from which light of the desired wavelength can be obtained. However, since it is difficult to precisely determine the reflective region of the first electrode 101 and the light-emitting region of the light-emitting layer from which light of the desired wavelength can be obtained, the above effects can be sufficiently obtained by assuming that any position on the first electrode 101 is a reflective region and any position on the light-emitting layer from which light of the desired wavelength can be obtained is a light-emitting region.

[0150] The light-emitting device shown in Figure 4(D) is a light-emitting device having a tandem structure. The tandem structure allows for a light-emitting device capable of high-brightness illumination. Furthermore, compared to a single structure, the tandem structure reduces the current required to achieve the same brightness, thereby improving reliability. It also reduces power consumption.

[0151] The light-emitting device shown in Figure 4(E) is an example of a tandem-structured light-emitting device shown in Figure 4(B). As shown in the figure, it has a structure in which three organic compound layers (103a, 103b, 103c) are stacked with charge generation layers (106a, 106b) in between. Each of the three organic compound layers (103a, 103b, 103c) has a light-emitting layer (113a, 113b, 113c), and the light-emitting colors of each light-emitting layer can be freely combined. For example, light-emitting layer 113a can be blue, light-emitting layer 113b can be red, green, or yellow, and light-emitting layer 113c can be blue. Alternatively, light-emitting layer 113a can be red, light-emitting layer 113b can be blue, green, or yellow, and light-emitting layer 113c can be red.

[0152] In the light-emitting device according to one aspect of the present invention described above, at least one of the first electrode 101 and the second electrode 102 is a light-transmitting electrode (such as a transparent electrode or a semi-transparent / semi-reflective electrode). When the light-transmitting electrode is a transparent electrode, the transmittance of visible light of the transparent electrode shall be 40% or more. When it is a semi-transparent / semi-reflective electrode, the reflectance of visible light of the semi-transparent / semi-reflective electrode shall be 20% or more and 80% or less, preferably 40% or more and 70% or less. Furthermore, these electrodes shall have a resistivity of 1 × 10⁻¹⁶ -2 It is preferable to keep it below Ωcm.

[0153] Furthermore, in the light-emitting device according to one aspect of the present invention described above, if one of the first electrode 101 and the second electrode 102 is a reflective electrode (reflective electrode), the visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. In addition, the resistivity of this electrode is 1 × 10⁻⁶. -2 It is preferable to keep it below Ωcm.

[0154] <Specific structure of a light-emitting device> Next, a specific structure of a light-emitting device according to one aspect of the present invention will be described. Here, we will use Figure 4(D), which has a tandem structure, for explanation. The same applies to the configuration of the organic compound layer for the single-structure light-emitting devices shown in Figures 4(A) and 4(C). Furthermore, if the light-emitting device shown in Figure 4(D) has a microcavity structure, the first electrode 101 is formed as a reflective electrode, and the second electrode 102 is formed as a semi-transparent / semi-reflective electrode. Thus, one or more desired electrode materials can be used and formed as a single layer or in a stacked configuration. The second electrode 102 is formed after the organic compound layer 103b is formed, by selecting an appropriate material.

[0155] <Materials for light-emitting devices> ≪Luminous layer≫ The light-emitting layers (113, 113a, 113b, 113c) are layers containing a light-emitting material. The light-emitting material that can be used in the light-emitting layers (113, 113a, 113b, 113c) can be any material that exhibits a light-emitting color such as blue, purple, blue-violet, green, yellow-green, yellow, orange, or red. Furthermore, if there are multiple light-emitting layers, a configuration exhibiting different light-emitting colors can be achieved by using different light-emitting materials in each layer (for example, white light emission obtained by combining complementary light-emitting colors). Additionally, a laminated structure in which each light-emitting layer contains a different light-emitting material is also possible.

[0156] Furthermore, the light-emitting layers (113, 113a, 113b, 113c) contain two or more organic compounds (host materials, etc.) in addition to the light-emitting substance (guest material).

[0157] For example, the structure described using Figure 1(B) can be used as the light-emitting layer 113. In the light-emitting layer 113, the host material 118 is present in the largest amount by weight, and the guest material 119 is dispersed in the host material 118. As the guest material 119, phosphorescent compounds or fluorescent compounds can be used. Mechanisms for efficiently emitting fluorescent compounds include TTA (triplet-triplet annihilation) and TADF (thermally activated delayed fluorescence), and these mechanisms can be adopted as needed.

[0158] Next, a preferred configuration of the light-emitting layer 113 using a phosphorescent compound as the guest material 119 will be described.

[0159] In a light-emitting layer 113 using a phosphorescent compound as the guest material 119, it is preferable that the T1 level of the host material 118 (organic compound 118_1 and organic compound 118_2) is higher than the T1 level of the guest material (guest material 119) of the light-emitting layer 113.

[0160] The lowest triplet excitation energy level (T1 level) can be calculated from the emission edge of the phosphorescence spectrum. Furthermore, compounds whose phosphorescence spectrum is not detectable at room temperature may be detectable at low temperatures (e.g., any temperature in the range of 4K to 80K). The sample form for measuring the emission spectrum of the luminescent central material can be a thin film or a solution, but a solution is preferred from the viewpoint of verifying the state of isolated molecules. A solvent with relatively low polarity, such as toluene or chloroform, is preferred for the solution. Also, in the case of phosphorescent compounds used as the luminescent central material, the phosphorescence spectrum can be observed even at room temperature. Therefore, the temperature at which the lowest triplet excitation energy level (T1 level) is measured can be either low temperature (e.g., any temperature in the range of 4K to 80K) or room temperature (e.g., 298K). The emission edge can be calculated by drawing a tangent line at the point where the absolute value of the slope on the short-wavelength side of the shortest wavelength peak (or shoulder peak) observed in the emission spectrum (phosphorescence spectrum) is maximum, and then taking the intersection of this tangent line with the horizontal axis (wavelength) or baseline.

[0161] Furthermore, if a phosphorescent component is not detected in the PL spectrum observed even at low temperatures in a thin film containing only the material to be measured, or in a solution to which only the material to be measured has been added, a phosphorescent sensitizer may be added. The phosphorescent sensitizer can be a phosphorescent material having a higher T1 level than the material to be measured. Specifically, Ir(ppy)3 can be used.

[0162] Examples of materials that can be used as compounds exhibiting phosphorescence in the light-emitting layer 113 include the following. Other phosphorescent substances can also be used.

[0163] 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) (abbreviation: [Ir(mpptz-dmp)3]) and tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]), Organometallic iridium complexes having a 1H-triazole skeleton, such as ris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]) and tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), and fac-tris[1-(2,6-diisopropyl] [Ir(iPrpim)3], Tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenantridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), Tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazole-2-yl-κN3}-4-cyanophenyl- Organometallic iridium complexes having an imidazole skeleton, such as κC)iridium(III) (abbreviation: CNImIr), organometallic iridium complexes having a benzimidazolidene skeleton, such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazine-1-yl-κC2)phenyl-κC]iridium(III) (abbreviation: [Ir(cb)3]), and bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ Iridium(III) tetrakis(1-pyrazolyl) borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: Firpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinate-N,C 2’Iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Examples include organometallic iridium complexes that use phenylpyridine derivatives having electron-withdrawing groups, such as iridium(III) acetylacetonate (abbreviated as FIr(acac)), as ligands. These compounds exhibit blue phosphorescence and have emission peaks in the wavelength range from 440 nm to 520 nm.

[0164] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6- Organometallic iridium complexes having a pyrimidine skeleton, such as (2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]), organometallic iridium complexes having a pyrazine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), and tris(2-phenylpyrimidinato-N,C 2’Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinate-N,C) 2’ Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinate)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinate)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinate-N,C) 2’ Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C) 2’Iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridinyl-κN)benzofloxacin [2,3-b]pyridinyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), {2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofloxacin [2,3-b]pyridin-7-yl-κC}bis{5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridinyl-κN]phenyl-κC}iridium(III) (abbreviation: Ir(5mtpy-d6)2(mbfpypy-iPr-d4)), [2-(methyl-d3)-8-(2-pyridinyl-κN)benzofloxacin[2,3-b]pyridinyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mbfp ypy-d3)), [2-(4-d3-methyl-5-phenyl-2-pyridinyl-κN2)phenyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mdppy-d3)]), [2-methyl-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(p Examples include organometallic iridium complexes having a pyridine skeleton, such as [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mdppy)), as well as rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]). These are mainly compounds that exhibit green phosphorescence and have emission peaks in the wavelength range of 500 nm to 600 nm. Organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they also exhibit outstanding reliability and luminescence efficiency.

[0165] Furthermore, organometallic iridium complexes having a pyrimidine skeleton, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), and bis[4,6-di(naphthalene-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), and tris(1-phenylisoquinolinato-N,C) 2’ Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C) 2’) Iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III) are organometallic iridium compounds with a pyridine skeleton. In addition to dinium complexes, other examples include platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviated as PtOEP), and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviated as [Eu(DBM)3(Phen)]) and tris[1-(2-tenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviated as [Eu(TTA)3(Phen)]). These exhibit emission peaks in the wavelength range of 600 nm to 700 nm. Furthermore, organometallic iridium complexes with a pyrazine skeleton yield a red emission with good chromaticity. Other known substances exhibiting red phosphorescence can also be used.

[0166] Furthermore, if the same light-emitting device contains light-emitting devices with different configurations, the light-emitting material may be a fluorescent material, a phosphorescent material, a material that exhibits thermally activated delayed fluorescence (TADF), or any other light-emitting material.

[0167] Next, we will describe a preferred configuration for the light-emitting layer 113, in which a fluorescent compound is used as the guest material 119, and in which the TADF mechanism is likely to occur.

[0168] TADF is a mechanism in which, in systems with a very small difference between the S1 and T1 energy levels, a small amount of thermal energy causes a reverse intersystem crossing from triplet excitation energy to singlet excitation energy, and fluorescence emission is generated from the converted singlet excitation energy. Therefore, it is possible to upconvert (reverse intersystem crossing) triplet excitation energy to singlet excitation energy, and singlet excited states can be efficiently generated. Furthermore, triplet excitation energy can be converted into emission. Materials that exhibit the TADF mechanism are sometimes called TADF materials.

[0169] The TADF mechanism may manifest with only one type of material or with two types of materials. Furthermore, an excited complex (also called an exciplex) formed by two types of materials has an extremely small difference between the S1 and T1 levels and functions as a TADF material capable of converting triplet excitation energy into singlet excitation energy.

[0170] The T1 level can be calculated using the emission edge of the phosphorescence spectrum observed at low temperatures (e.g., any temperature in the range of 4K to 80K). The S1 level can be calculated using the emission edge of the PL spectrum measured at low temperatures (e.g., any temperature in the range of 4K to 80K) or at room temperature. Furthermore, the absorption spectrum measured at room temperature can be used as an indicator of the S1 level of a fluorescent material. For example, the absorption spectrum can be measured at room temperature, and the energy at the absorption edge on the longer wavelength side can be considered the S1 level. The absorption edge on the longer wavelength side of the absorption spectrum can be calculated by drawing a tangent line at the point where the slope on the longest wavelength side of the peak (or shoulder peak) observed at the longest wavelength of the absorption spectrum is minimum (maximum absolute value), and then calculating the S1 level from the intersection of this tangent line with the horizontal axis (wavelength) or baseline. It is particularly preferable to compare the emission edges of the fluorescence spectrum and the phosphorescence spectrum when comparing the S1 and T1 levels. Furthermore, the difference between the S1 level and the T1 level is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0171] Furthermore, when using TADF material as a light-emitting material, it is preferable that the S1 level of the host material is higher than the S1 level of the TADF material. Also, it is preferable that the T1 level of the host material is higher than the T1 level of the TADF material.

[0172] As TADF materials, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc., can be used. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can be used. Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complexes (SnF2(Proto IX)), mesoporphyrin-tin fluoride complexes (SnF2(Meso IX)), hematoporphyrin-tin fluoride complexes (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complexes (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complexes (SnF2(OEP)), etioporphyrin-tin fluoride complexes (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complexes (PtCl2OEP), as shown in the following structural formulas.

[0173] [ka]

[0174] Furthermore, the following structural formulas represent 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviated as PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazol (abbreviated as PCCzTzn), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-3,3'-bi-9H-carbazol (abbreviated as PCCzPTzn), and 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviated as PXZ). Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring can also be used, such as -TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridine-10-yl)-9H-xanthene-9-one (abbreviated as ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviated as DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviated as ACRSA). The heterocyclic compound is preferred because it has both a π-electron-excess heteroaromatic ring and a π-electron-deficient heteroaromatic ring, resulting in high electron transport and hole transport properties. Among the skeletons having a π-electron-deficient heteroaromatic ring, the pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, the benzoflopyrimidine skeleton, benzothienopyrimidine skeleton, benzoflopyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptability and are reliable. Furthermore, among the skeletons having a π-electron-excess heteroaromatic ring, the acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are preferred because they are stable and reliable, and therefore it is preferable to have at least one of these skeletons.Furthermore, a dibenzofuran skeleton is preferred as the furan skeleton, and a dibenzothiophene skeleton is preferred as the thiophene skeleton. In addition, the indole skeleton, carbazole skeleton, indrocarbazole skeleton, bicarbazole skeleton, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton are particularly preferred as the pyrrole skeleton. Substances in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded are particularly preferred because both the electron-donating and electron-accepting properties of the π-electron-rich heteroaromatic ring are strengthened, and the energy difference between the S1 and T1 levels is reduced, thus efficiently obtaining thermally activated delayed fluorescence. In addition, an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded may be used instead of the π-electron-deficient heteroaromatic ring. Furthermore, aromatic amine skeletons, phenazine skeletons, etc., can be used as the π-electron-rich skeleton. Furthermore, as π-electron-deficient skeletons, xanthene skeletons, thioxanthene dioxide skeletons, oxadiazole skeletons, triazole skeletons, imidazole skeletons, anthraquinone skeletons, boron-containing skeletons such as phenylborane or volanthrene, aromatic rings or heteroaromatic rings having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, carbonyl skeletons such as benzophenone, phosphine oxide skeletons, sulfone skeletons, etc., can be used. In this way, π-electron-deficient skeletons and π-electron-excess skeletons can be used instead of at least one of π-electron-deficient heteroaromatic rings and π-electron-excess heteroaromatic rings.

[0175] [ka]

[0176] Furthermore, TADF materials that enable extremely fast and reversible intersystem crossing, and in which singlet and triplet excited states emit light according to a thermal equilibrium model, may also be used. Such TADF materials have an extremely short emission lifetime (excitation lifetime) as TADF materials, and can suppress efficiency degradation in the high-brightness region of light-emitting devices. Specifically, materials with molecular structures like those shown below can be used.

[0177] [ka]

[0178] Next, we will describe a preferred configuration for the light-emitting layer 113 in which a fluorescent compound is used as the guest material 119, and the TTA mechanism is generated.

[0179] In the case of a light-emitting device that uses a fluorescent material in the light-emitting layer and utilizes the TTA mechanism to enhance luminescence efficiency, it is preferable that the lowest singlet excitation energy level (S1 level) of the host material is higher than the S1 level of the fluorescent material, and the lowest triplet excitation energy level (T1 level) of the host material is lower than the T1 level of the fluorescent material. Furthermore, it is more preferable that the difference between the HOMO level of the host material and the HOMO level of the fluorescent material is 0.25 eV or more. In addition, it is preferable that the concentration of the fluorescent material in the light-emitting layer is 0.5 wt% to 25 wt% relative to the host material. With this configuration, holes are more easily trapped in the light-emitting layer, carriers recombine locally in the region on the hole transport layer side of the light-emitting layer, and the exciton density increases, thereby improving the efficiency of TTA. Another configuration that enhances luminescence efficiency using TTA is that it is more preferable that the LUMO level of the fluorescent material is lower than the LUMO level of the host material. This configuration makes it easier for electrons to be trapped within the light-emitting layer, causing localized carrier recombination in the region of the light-emitting layer on the hole transport layer side, thereby increasing the exciton density and improving the efficiency of TTA.

[0180] The energies of the HOMO and LUMO levels used herein can be determined by electrochemical measurements. Typical examples of electrochemical measurements include square wave voltammetry (SWV), cyclic voltammetry (CV), and differential pulse voltammetry (DPV).

[0181] Specifically, in square wave voltammetry (SWV) measurements, the energies (E) of the HOMO and LUMO levels are obtained by changing the potential of the working electrode relative to the reference electrode. Oxidation peak potential (Ep ox) and reduction peak potential (Ep red The differential current between the forward and reverse currents obtained in a square wave voltammetry (SWV) measurement is used. In the measurement, the HOMO level is determined from the positive potential scan, and the LUMO level is determined from the negative potential scan.

[0182] For example, the parameters for measurement can be set as follows: potential increase Incr E (V) = 0.004, amplitude (V) = 0.025, and frequency (Hz) = 15. The scan speed (mV / s) in the measurement can be calculated by multiplying the potential increase (Incr E(V)) by the frequency (f(Hz)). Specifically, under these parameter settings, 0.004(V) × 15(1 / s) = 0.06(V / s), so the scan speed is 0.06(V / s).

[0183] Furthermore, the specific procedures for calculating the HOMO and LUMO levels will be explained. The oxidation peak potential (Ep) obtained from the rectangular wave voltammogram of the material is then described. ox ), or reduction peak potential (Ep red ) is determined, and the potential energy (E) of the reference electrode with respect to the vacuum level is calculated. x By subtracting from ), the HOMO level ((E) = E x -Ep ox ), and the energy of the LUMO level ((E)=E x -Ep red ) can be calculated for each of them.

[0184] Furthermore, in cyclic voltammetry (CV) measurements, the energy (E) of the HOMO and LUMO levels is obtained by changing the oxidation peak potential (E) relative to the reference electrode. pa ), and reduction peak potential (E pc Based on this, it can be calculated. In the measurement, the HOMO level is determined from the positive potential scan, and the LUMO level is determined from the negative potential scan. The scan speed in the measurement is set to 0.1 V / s.

[0185] The specific procedures for calculating the HOMO level and LUMO level using CV measurement are described. From the oxidation peak potential (E pa ), and the reduction peak potential (E pc ) obtained from the cyclic voltammogram of the material, the standard redox potential (E o )(=(E pa +E pc ) / 2) is obtained, and by subtracting it from the potential energy (E x ) of the reference electrode with respect to the vacuum level, the energies (E) of the HOMO level and LUMO level (=E x -E o ) can be obtained respectively.

[0186] Note that the above shows the case where a reversible redox wave is obtained. When an irreversible redox wave is obtained, for the calculation of the HOMO level, a value obtained by subtracting a certain value (0.1 eV) from the oxidation peak potential (E pa ) is assumed to be the reduction peak potential (E pc ), and the standard redox potential (E o ) is obtained to one decimal place. Also, for the calculation of the LUMO level, a value obtained by adding a certain value (0.1 eV) to the reduction peak potential (E pc ) is assumed to be the oxidation peak potential (E pa ), and the standard redox potential (E o ) is obtained to one decimal place.

[0187] Note that the S1 level and T1 level can adopt values calculated from the emission end of the aforementioned phosphorescence or fluorescence spectrum and the absorption end of the absorption spectrum.

[0188] Examples of materials that can be used as the luminescent material (fluorescent luminescent material) exhibiting fluorescent emission in the light-emitting layer 113 include the following. Also, other fluorescent luminescent materials can be used.

[0189] 5,6-Bis[4-(10-phenyl-9-antryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-Bis[4'-(10-phenyl-9-antryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-Diphenyl-N,N'-Bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyren-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-Bis(3-methylphenyl)-N,N'-Bis[3-(9-phenyl-9H-fluoren-9-yl )phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviation: DPABPA), N,9 -Diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA) 9,10-bis(biphenyl-2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubren, 5,12-bis(biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyra n-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluorantene-3,10-diamine (abbreviation) Name: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-Bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naph Examples include [1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazole-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02). In particular, condensed aromatic diamine compounds, such as pyrenediamine compounds like 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are preferred because they have high hole-trapping properties and excellent luminescence efficiency or reliability.

[0190] Also, 5,9-diphenyl-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene (abbreviation: DABNA-1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazavolin-3-amine (abbreviation: DABNA-2), 2,12-di(tert-butyl) -5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazabolin-7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl)-5H,9H-[1,4]benzazabolino[2, 3,4-kl]phenazavolin-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazavolino[2,3,4-kl]phenazavolin (abbreviation: Me-tBu4DABNA), N7,N7,N13,N13,5,9,11 Materials having a diazabora-naphthanthracene skeleton, such as 15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborino[2,3,4-kl][1,4]benzazaborino[4',3',2':4,5][1,4]benzazaborino[3,2-b]phenazaborin-7,13-diamine (abbreviation: ν-DABNA), can be used.

[0191] As the electron-transporting material used as the host material for the light-emitting layer 113, for example, metal complexes such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviated as BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviated as BAlq), bis(8-quinolinolato)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviated as ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviated as ZnBTZ), or organic compounds having a π-electron-deficient heteroaromatic ring can be used. Examples of organic compounds having a π-electron-deficient heteroaromatic ring include 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), and 1,3-bis[5-(4-tert-butylphenyl)-1,3,4- Oxadiazole-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl Organic compounds containing heteroaromatic rings with an azole skeleton, such as phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 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: 2mDBTBP DBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 2,4-Bis[4-(1-naphthyl)phenyl]-6-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine Organic compounds containing heteroaromatic rings with a diazine skeleton, such as 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy) and 1,3,5-tri[(3-pyridyl)phenyl-3-yl]benzene (abbreviation: TmPyPB), and 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)bi [phenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobio[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan- 6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-[3'-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,Examples of organic compounds containing heteroaromatic rings having a triazine skeleton include 5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as PCDBfTzn) and 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). Among the above, organic compounds containing heteroaromatic rings having a diazine skeleton, organic compounds containing heteroaromatic rings having a pyridine skeleton, and organic compounds containing heteroaromatic rings having a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing heteroaromatic rings having a diazine (pyrimidine and pyrazine) skeleton and organic compounds containing heteroaromatic rings having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage.

[0192] As the hole transport material used as the host material for the light-emitting layer 113, an organic compound having an amine skeleton or a π-electron-rich heteroaromatic ring can also be used. Examples of such organic compounds having an amine skeleton or a π-electron-rich heteroaromatic ring 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), and 4-phenyl-4'-(9-phenylfluorene-9-yl) Triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine Aromatic compounds such as fluoramine (abbreviated as PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviated as PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobio[9H-fluoren]-2-amine (abbreviated as PCBASF) Compounds having a fragrance amine skeleton, compounds having a carbazole skeleton such as 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-di(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), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II), 2,Compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), etc., and compounds having a furan skeleton such as 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), etc. Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Also, the organic compounds exemplified as materials having hole transportability in the hole transport layer 112 can also be used as the host hole transport material.,

[0193] Note that by mixing an electron transport material and a hole transport material, the transportability of the light-emitting layer 113 can be easily adjusted, and the control of the recombination region can be easily performed.

[0194] Also, TADF materials can also be used as an electron transport material or a hole transport material. As TADF materials that can be used as host materials, those previously listed as TADF materials can be used in the same manner. When a TADF material is used as a host material, the triplet excitation energy generated in the TADF material is converted into singlet excitation energy by reverse intersystem crossing, and further energy transfer to the light-emitting substance can also increase the light emission efficiency of the light-emitting device. At this time, the TADF material functions as an energy donor, and the light-emitting substance functions as an energy acceptor.

[0195] This is very effective when the above luminescent material is a fluorescent luminescent material. Also, at this time, in order to obtain high luminous efficiency, it is preferable that the S1 level of the TADF material is higher than the S1 level of the fluorescent luminescent material. Further, it is preferable that the T1 level of the TADF material is higher than the S1 level of the fluorescent luminescent material. Therefore, it is preferable that the T1 level of the TADF material is higher than the T1 level of the fluorescent luminescent material.

[0196] Moreover, it is preferable to use a TADF material that exhibits luminescence overlapping with the wavelength of the absorption band on the lowest energy side of the fluorescent luminescent material. By doing so, the transfer of excitation energy from the TADF material to the fluorescent luminescent material becomes smooth, and luminescence can be obtained efficiently, which is preferable.

[0197] Furthermore, for singlet excitation energy to be efficiently generated from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. It is also preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. To achieve this, it is preferable that the fluorescent material has protecting groups around the luminescent phosphodiocyte (the skeleton that causes luminescence). Preferred protecting groups are substituents without π bonds, and saturated hydrocarbons are preferred. Specifically, examples include alkyl groups having 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, and trialkylsilyl groups having 3 to 10 carbon atoms. It is even more preferable to have multiple protecting groups. Substituents without π bonds have poor carrier transport function, and therefore can increase the distance between the TADF material and the luminescent phosphodiocyte of the fluorescent material with little effect on carrier transport and carrier recombination. Here, the luminescent phosphodiocyte refers to the atomic group (skeleton) that causes luminescence in the fluorescent material. The luminescent phosphophore preferably has a skeleton containing π bonds, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of such luminescent phosphophores include phenanthrene skeletons, stilbene skeletons, acridone skeletons, phenoxazine skeletons, phenothiazine skeletons, naphthalene skeletons, anthracene skeletons, fluorene skeletons, chrysene skeletons, triphenylene skeletons, tetracene skeletons, pyrene skeletons, perylene skeletons, coumarin skeletons, quinacridone skeletons, and naphthobisbenzofuran skeletons. Fluorescent materials having naphthalene, anthracene, fluorene, chrysene, triphenylene, tetracene, pyrene, perylene, coumarin, quinacridone, and naphthobisbenzofuran skeletons are particularly preferred due to their high fluorescence quantum yield.

[0198] Furthermore, when a fluorescent material is used as the light-emitting material in the light-emitting layer 113, it is more preferable to use a condensed polycyclic aromatic compound such as anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, or dibenzo[g,p]chrysene derivatives as the host material, which is an organic compound with a large singlet excited state energy level and a small triplet excited state energy level. Materials having an anthracene skeleton are particularly preferred. When a substance having an anthracene skeleton is used as the host material for the fluorescent material, it is possible to realize a light-emitting layer with good luminescence efficiency and durability. As a substance having an anthracene skeleton to be used as the host material, a diphenylanthracene skeleton, and especially a substance having a 9,10-diphenylanthracene skeleton, are preferred because they are chemically stable. Examples of such substances include organic compounds having heteroaromatic rings and aromatic compounds consisting of aromatic hydrocarbons. Examples of organic compounds containing heteroaromatic rings include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviated as cgDBCzPA), and 6-[3-(9,10-diphenyl-2-anthryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviated as 2mBnfPPA). Examples include 2-(10-phenyl-9-anthryl)benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA), 1-{4-[10-(biphenyl-4-yl)-9-anthryl]phenyl}-2-ethyl-1H-benzimidazole (abbreviated as EtBImPBPhA), 1-[10-(phenyl-2,3,4,5,6-d5)-9-anthryl]benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA-02-d5), and 7-(phenyl-2,3,4,5,6-d5)-1-[10-(phenyl-2,3,4,5,6-d5)-9-anthryl]dibenzofuran (abbreviated as PDBfPhA-d10).Furthermore, examples of aromatic compounds consisting of aromatic hydrocarbons include 9-phenyl-10-[4'-(9-phenyl-9H-fluoren-9-yl)biphenyl-4-yl]anthracene (abbreviated as FLPPA), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviated as α,βADN), 2-(10-phenylanthracene-9-yl)dibenzofuran, 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviated as βN-mβNPAnth), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth), and 2,9-di(1-naphthyl)-10-phenylanthracene (abbreviated as 2αN-αNPhA). The light hydrogen atoms in these organic compounds having heteroaromatic rings and aromatic compounds consisting of aromatic hydrocarbons may each be independently deuterium.

[0199] Specifically, as organic compounds having the heteroaromatic ring described above, organic compounds represented by structural formulas (100) to (118) can be used in a light-emitting device according to one aspect of the present invention.

[0200] [ka]

[0201] [ka]

[0202] The organic compounds represented by structural formulas (100) to (118) above are examples of organic compounds having heteroaromatic rings, and the organic compounds used in the light-emitting device according to one embodiment of the present invention are not limited thereto.

[0203] Furthermore, specifically, as aromatic compounds consisting of the above-mentioned aromatic hydrocarbons, organic compounds represented by structural formulas (200) to (232) can be used in a light-emitting device according to one aspect of the present invention.

[0204] [ka]

[0205] [Chemical formula]

[0206] [Chemical formula]

[0207] The organic compounds represented by the above structural formula (200) to structural formula (232) are an example of organic compounds having a heteroaromatic ring, and the organic compounds used in the light-emitting device of one aspect of the present invention are not limited thereto.

[0208] In addition, as a part of the above mixed materials, a phosphorescent substance can be used. The phosphorescent substance can be used as an energy donor that supplies excitation energy to the fluorescent substance when the fluorescent substance is used as the luminescent substance.

[0209] Further, an exciplex may be formed between the above mixed materials. By selecting a combination that forms an exciplex that emits light overlapping the wavelength of the absorption band on the lowest energy side of the luminescent substance, energy transfer becomes smooth and light emission can be obtained efficiently, which is preferable. In addition, since the driving voltage is also reduced by using this configuration, it is preferable.

[0210] Note that at least one of the materials forming the exciplex may be a phosphorescent substance. By doing so, triplet excitation energy can be efficiently converted into singlet excitation energy by reverse intersystem crossing.

[0211] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO level of the material having hole-transporting properties is higher than the HOMO level of the material having electron-transporting properties. Also, it is preferable that the LUMO level of the material having hole-transporting properties is higher than the LUMO level of the material having electron-transporting properties.

[0212] The formation of excited complexes can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectra of each individual material (or has a new peak on the longer wavelength side). Alternatively, it can be confirmed 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 made by mixing these materials, and observing differences in the transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component or a larger proportion of the delayed component than the transient PL lifetime of each individual material. Furthermore, the transient PL mentioned above can be replaced with transient electroluminescence (EL). That is, the formation of excited complexes can also be confirmed 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 made by mixing these materials, and observing the differences in the transient response.

[0213] The light-emitting layer 113 can be formed by methods other than the light-emitting mechanism, such as vapor deposition (including vacuum deposition), inkjet printing, coating, and gravure printing. In addition to the materials mentioned above, it may also contain inorganic compounds such as quantum dots or polymer compounds (oligomers, dendrimers, polymers, etc.).

[0214] ≪Hole Injection Layer≫ The hole injection layers (111, 111a, 111b) are layers that inject holes from the first electrode 101, which is the anode, and the charge generation layers (106, 106a, 106b) into the organic compound layers (103, 103a, 103b), and are layers that contain organic acceptor material and material with high hole injection potential.

[0215] For the hole injection layers (111, 111a, 111b), compounds having electron-withdrawing groups (halogen groups or cyano groups) can be used, 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-dicyanomethylene-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 heteroatoms, such as HAT-CN, are thermally stable and preferred. Furthermore, radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group or a cyano group) [3] are preferred because they have very high electron-accepting properties. Specific examples include α,α',α''-1,2,3-cyclopropanetriylidenates (4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile) (abbreviated as Rad), α,α',α''-1,2,3-cyclopropanetriylidenates [2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenates [2,3,4,5,6-pentafluorobenzeneacetonitrile]. In addition to the organic compounds mentioned above, other substances with acceptor properties that can be used include molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, and the like.In addition, hole injection layers (111, 111a, 111b) can also be formed by phthalocyanine-based compounds such as phthalocyanine (abbreviated as H2Pc), phthalocyanine-based complex compounds such as copper phthalocyanine (CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) and N,N'-bis[4-bis(3-methylphenyl)aminophenyl]-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as DNTPD), or polymers such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviated as PEDOT / PSS). Accepting materials can extract electrons from adjacent hole transport layers (or hole transporting materials) by applying an electric field.

[0216] Furthermore, among substances with acceptor properties, organic compounds with acceptor properties are easy to use because they are readily deposited and easy to form films.

[0217] Furthermore, a composite material containing the above-mentioned acceptor substance in a hole-transporting material can also be used as the hole injection layer (111, 111a, 111b). By using a composite material containing an acceptor substance in a hole-transporting material, it is possible to select the material for forming the electrode regardless of the work function. In other words, not only materials with a large work function but also materials with a small work function can be used as the anode (first electrode 101).

[0218] Various organic compounds can be used as hole-transporting materials in composite materials, including aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.). -6 cm 2 It is preferable that the material has a hole mobility of / Vs or higher. Below, we specifically list organic compounds that can be used as hole transporting materials in composite materials.

[0219] Aromatic amine compounds that can be used in composite materials include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), N,N'-bis[4-bis(3-methylphenyl)aminophenyl]-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B). Specifically, carbazole derivatives include 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenyl Carbazole (abbreviated as PCzPCN1), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviated as TCPB), 9-[4-(10-phenyl-9-antryl)phenyl]-9H-carbazole (abbreviated as CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. can be used.Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert- Examples include butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, and 2,5,8,11-tetra(tert-butyl)perylene. In addition, pentacene, coronene, and the like can also be used. Furthermore, the compound may have a vinyl skeleton. Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviated as DPVBi) and 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviated as DPVPA). Organic compounds according to one embodiment of the present invention can also be used.

[0220] Furthermore, polymer compounds such as poly(N-vinylcarbazole) (abbreviated as PVK), poly(4-vinyltriphenylamine) (abbreviated as PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviated as PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviated as Poly-TPD) can also be used.

[0221] The hole-transporting material used in the composite material more preferably has at least one of the following skeletons: carbazole, dibenzofuran, dibenzothiophene, and anthracene. In particular, it may be an aromatic amine having substituents including a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Furthermore, it is preferable that these organic compounds are substances having an N,N-bis(4-biphenyl)amino group, as this allows for the creation of light-emitting devices with a good lifetime. Specifically, the organic compounds described above include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), and 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl). )-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan -4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BB AβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-([2,1'-binaphthyl]-6-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-([2,1'-binaphthyl]-7-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-Diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-Diphenyl-4''-([2,2'-binaphthyl]-6-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-Diphenyl-4''-([2,2'-binaphthyl]-7-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-Diphenyl-4''-([1,2'-binaphthyl]-4-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-( [1,2'-binaphthyl]-5-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl 4,4'-Bis(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-Diphenyl-4''-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tris(biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyl Triphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis(biphenyl-4-yl)-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobio[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluoren]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9 H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine Examples include N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-2-amine, and N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-1-amine.

[0222] Furthermore, it is even more preferable that the hole-transporting material used in the composite material has a relatively low HOMO level between -5.7 eV and -5.4 eV. Having a relatively low HOMO level in the hole-transporting material used in the composite material facilitates the injection of holes into the hole transport layer 112 and makes it easier to obtain a light-emitting device with a good lifetime. In addition, having a relatively low HOMO level in the hole-transporting material used in the composite material moderately suppresses hole induction, resulting in a light-emitting device with an even better lifetime.

[0223] Furthermore, by mixing alkali metal or alkaline earth metal fluoride into the above composite material (preferably with an atomic ratio of fluorine atoms of 20% or more in the layer), the refractive index of the layer can be reduced. This also allows for the formation of a layer with a low refractive index within the organic compound layer 103, thereby improving the external quantum efficiency of the light-emitting device.

[0224] By forming hole injection layers (111, 111a, 111b), hole injection performance is improved, and a light-emitting device with a low driving voltage can be obtained.

[0225] ≪Hole transport layer≫ The hole transport layers (112, 112a, 112b) are layers containing a hole-transporting material, and the hole-transporting material exemplified as the material for the hole injection layers (111, 111a, 111b) can be used. Since the hole transport layers (112, 112a, 112b) have the function of transporting holes injected into the hole injection layers (111, 111a, 111b) to the light-emitting layers (113, 113a, 113b, 113c), it is preferable that they have the same or close HOMO level as the HOMO level of the hole injection layers (111, 111a, 111b).

[0226] Also, 1 x 10 -6 cm 2It is preferable that the material has a hole mobility of / Vs or higher. However, other materials may be used as long as they have higher hole transport capabilities than electron transport capabilities. Furthermore, the layer containing the material with high hole transport capabilities may be a single layer, or two or more layers made of the above material may be stacked.

[0227] Materials that can be used in the hole transport layers (112, 112a, 112b) 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'-spirobio[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), and 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPA). FLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4'' Compounds having an aromatic amine skeleton such as -(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di (N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,Examples include compounds having a carbazole skeleton such as 3'-bicarbazole (abbreviation: mBPCCBP), compounds having a thiophene skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among those mentioned above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferred because they offer good reliability, high hole transport properties, and contribute to reducing the driving voltage. Furthermore, the materials listed as having hole transport properties for the composite material of the hole injection layer 111 can also be suitably used as materials constituting the hole transport layer 112.

[0228] ≪Electron transport layer≫ The electron transport layers (114, 114a, 114b) have the function of transporting electrons injected from the other electrode of the pair (first electrode 101 or second electrode 102) to the light-emitting layer 113 via the electron injection layers (115, 115a, 115b).

[0229] Furthermore, as an electron-transporting material, it is an organic compound that possesses electron-transporting properties, and its electron mobility at an electric field strength [V / cm] square root of 600 is 1 × 10⁻⁶. -6 cm 2A substance having an electron mobility of / Vs or higher is preferred. However, any substance that has higher electron transport than holes can be used. As the above organic compound, an organic compound having a π-electron-deficient heteroaromatic ring is preferred. As an organic compound having a π-electron-deficient heteroaromatic ring, it is preferable that it be any or more of the following: 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.

[0230] Organic compounds having a π-electron-deficient heteroaromatic ring that can be used in the above electron transport layer include, specifically, 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), 1,3-bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as OXD-7), and 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl]benzene. Organic compounds having an azole skeleton, such as sadiazole-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), and 4,4'-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviation: BzOs), as well as 3,5-bis[3-(9H-carbazole-9-yl)phenyl Organic compounds containing heteroaromatic rings with a pyridine skeleton, such as [nyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[(3-pyridyl)phenyl-3-yl]benzene (abbreviation: TmPyPB), vasophenanthroline (abbreviation: Bphen), vasocuproin (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 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-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,[h]Quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]Quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]Quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl -4-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9 H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzoflo[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 8-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]flo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfp m), 8-([2,2'-binaphthalene]-6-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofloflo[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-Bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,4-Bis[4-(1-naphthyl)phenyl]-6-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-Bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazoline-2-yl]-7H-dibenzo[c,g]cal Organic compounds having a diazine skeleton, such as Bazole (abbreviation: PC-cgDBCzQz), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobio[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1 ,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 9-[4-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-phenylindoro[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3'-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3 Examples of organic compounds having a triazine skeleton include ,5-triazine (abbreviated as mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as PCDBfTzn), and 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). Among the above, organic compounds containing a heteroaromatic ring having a diazine skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing heteroaromatic rings with a diazine (pyrimidine and pyrazine) skeleton, and organic compounds containing heteroaromatic rings with a triazine skeleton, exhibit high electron transport properties and contribute to reducing the driving voltage.

[0231] Furthermore, the electron transport layers (114, 114a, 114b) may be not only a single layer, but also two or more layers made of the above material stacked together.

[0232] Furthermore, a layer for controlling the movement of electron carriers may be provided between the electron transport layers (114, 114a, 114b) and the light-emitting layers (113, 113a, 113b, 113c). This layer is made by adding a small amount of a substance with high electron-trapping properties to the electron-transporting material described above, and it is possible to adjust the carrier balance by suppressing the movement of electron carriers. Such a configuration is highly effective in suppressing problems that occur when electrons penetrate the light-emitting layer (for example, a decrease in device lifespan).

[0233] ≪Electron injection layer≫ The electron injection layers (115, 115a, 115b) have the function of promoting electron injection by reducing the electron injection barrier from the second electrode 102.

[0234] Furthermore, for example, Group 1 metals, Group 2 metals, or their oxides, halides, carbonates, etc., can be used. Also, composite materials of the electron-transporting material and an electron-donating material can be used. Examples of electron-donating materials include Group 1 metals, Group 2 metals, or their oxides. Specifically, lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF), calcium fluoride (CaF2), lithium oxide (LiO2) x Alkali metals, alkaline earth metals, or compounds thereof can be used. Rare earth metal compounds such as erbium fluoride (ErF3) can also be used. An electride may also be used in the electron injection layer 115. Examples of such electrides include a substance obtained by adding electrons to a mixed oxide of calcium and aluminum at a high concentration. In addition, the electron injection layers (115, 115a, 115b) may be made of the same material used in the electron transport layers (114, 114a, 114b).

[0235] Furthermore, a composite material obtained by mixing an organic compound with an electron donor may be used in the electron injection layers (115, 115a, 115b). Such a composite material exhibits excellent electron injection and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material with excellent electron transport properties, and specifically, for example, the substance that constitutes the electron transport layer 114 described above (metal complex, or heteroaromatic compound, etc.) can be used. The electron donor can be any substance that exhibits electron-donating properties to the organic compound. Specifically, alkali metals, alkaline earth metals, or rare earth metals are preferred, such as lithium, sodium, cesium, magnesium, calcium, erbium, and ytterbium. Alkali metal oxides or alkaline earth metal oxides are also preferred, such as lithium oxide, calcium oxide, and barium oxide. Lewis bases such as magnesium oxide can also be used. Furthermore, organic compounds such as tetrathiafulvalene (abbreviated as TTF) can also be used.

[0236] The light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer described above can be formed by methods such as vapor deposition (including vacuum deposition), inkjet printing, coating, and gravure printing. In addition to the materials described above, inorganic compounds such as quantum dots or polymer compounds (oligomers, dendrimers, polymers, etc.) may also be used for the light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer.

[0237] Furthermore, the quantum dots may include colloidal quantum dots, alloy quantum dots, core-shell quantum dots, core quantum dots, etc. Quantum dots containing elemental groups from groups 2 and 16, 13 and 15, 13 and 17, 11 and 17, or 14 and 15 may also be used. Alternatively, quantum dots containing elements such as cadmium (Cd), selenium (Se), zinc (Zn), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium (Ga), arsenic (As), and aluminum (Al) may be used.

[0238] ≪A pair of electrodes≫ The first electrode 101 and the second electrode 102 function as the anode or cathode of the light-emitting device. The first electrode 101 and the second electrode 102 can be formed using metals, alloys, conductive compounds, mixtures thereof, or laminates.

[0239] Preferably, one of the first electrode 101 or the second electrode 102 is formed of a conductive material having the function of reflecting light. Examples of such conductive materials include aluminum (Al) or alloys containing Al. Examples of alloys containing Al include alloys containing Al and L (where L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni), and lanthanum (La)), such as alloys containing Al and Ti, or Al, Ni, and La. Aluminum has low resistance and high light reflectivity. In addition, since aluminum is abundant in the Earth's crust and inexpensive, using aluminum can reduce the cost of manufacturing light-emitting devices. In addition, alloys containing silver (Ag), or Ag and N (where N represents one or more of yttrium (Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium (Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir), or gold (Au) may be used. Examples of silver-containing alloys include alloys containing silver, palladium, and copper; alloys containing silver and copper; alloys containing silver and magnesium; alloys containing silver and nickel; alloys containing silver and gold; and alloys containing silver and ytterbium. Other transition metals such as tungsten, chromium (Cr), molybdenum (Mo), copper, and titanium can also be used.

[0240] Furthermore, the light emitted from the light-emitting layer is extracted through one or both of the first electrode 101 and the second electrode 102. Therefore, it is preferable that at least one of the first electrode 101 and the second electrode 102 be made of a conductive material that has the function of transmitting light. The conductive material has a visible light transmittance of 40% to 100%, preferably 60% to 100%, and a resistivity of 1 × 10⁻⁶. -2 Examples include conductive materials with a conductivity of Ω·cm or less.

[0241] Furthermore, the first electrode 101 and the second electrode 102 may be formed from a conductive material having both a light-transmitting function and a light-reflecting function. The conductive material has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and a resistivity of 1 × 10⁻⁶. -2 Examples of conductive materials include those with a conductivity of Ω·cm or less. For example, they can be formed using one or more types of conductive metals, alloys, or conductive compounds. Specifically, metal oxides such as indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide (ITSO), indium zinc oxide, indium tin oxide containing titanium, indium titanium oxide, and indium oxide containing tungsten and zinc oxide can be used. In addition, thin metal films that transmit light (preferably with a thickness of 1 nm to 30 nm) can be used. As a metal, for example, Ag can be used. As an alloy, alloys such as Ag and Al, Ag and Mg, Ag and Au, Ag and Yb can be used.

[0242] In this specification, a material having the function of transmitting light is any material that has the function of transmitting visible light and is conductive, and in addition to oxide conductors such as ITO as described above, it also includes oxide semiconductors or organic conductors containing organic matter. Examples of organic conductors containing organic matter include composite materials obtained by mixing an organic compound with an electron donor, and composite materials obtained by mixing an organic compound with an electron acceptor. Inorganic carbon-based materials such as graphene may also be used. The resistivity of the material is preferably 1 × 10⁻⁶. 5 Ω·cm or less, more preferably 1 × 10⁻⁶ 4 It is less than or equal to Ω·cm.

[0243] Alternatively, one or both of the first electrode 101 and the second electrode 102 may be formed by stacking multiple of the above materials.

[0244] Furthermore, to improve light extraction efficiency, a material with a higher refractive index than the electrode may be formed in contact with an electrode that has the function of transmitting light. Such a material can be any material that has the function of transmitting visible light, and may or may not be conductive. For example, in addition to the oxide conductors mentioned above, oxide semiconductors and organic materials can be used. Examples of organic materials include the materials exemplified in the light-emitting layer, hole injection layer, hole transport layer, electron transport layer, or electron injection layer. Inorganic carbon-based materials or thin metal films that transmit light to a certain extent can also be used, and multiple layers of several nanometers to tens of nanometers may be stacked.

[0245] When the first electrode 101 or the second electrode 102 functions as a cathode, it is preferable to use a material with a small work function (3.8 eV or less). For example, elements belonging to Group 1 or Group 2 of the periodic table (alkali metals such as lithium, sodium, and cesium; alkaline earth metals such as calcium and strontium; magnesium, etc.), alloys containing these elements (e.g., Ag and Mg, Al and Li), rare earth metals such as europium (Eu) and Yb, alloys containing these rare earth metals, alloys containing aluminum and silver, etc. can be used.

[0246] Furthermore, when using the first electrode 101 or the second electrode 102 as an anode, it is preferable to use a material with a large work function (4.0 eV or more).

[0247] Furthermore, the first electrode 101 and the second electrode 102 may be a laminate of a conductive material having the function of reflecting light and a conductive material having the function of transmitting light. In that case, the first electrode 101 and the second electrode 102 are preferable because they can have a function of adjusting the optical distance so that they can resonate with light of a desired wavelength from each light-emitting layer and intensify the light of that wavelength.

[0248] The first electrode 101 and the second electrode 102 can be formed using methods such as sputtering, vapor deposition, printing, coating, MBE (Molecular Beam Epitaxy), CVD, pulsed laser deposition, ALD (Atomic Layer Deposition), etc., as appropriate.

[0249] ≪Charge generation layer (intermediate layer)≫ The charge generation layer 106 has the function of injecting electrons into the organic compound layer 103a and holes into the organic compound layer 103b when a voltage is applied between the first electrode (anode) 101 and the second electrode (cathode) 102. The charge generation layer 106 may be configured in which an electron acceptor is added to a hole transport material (also called a p-type layer), or in which an electron donor is added to an electron transport material (also called an electron injection buffer layer). Furthermore, both of these configurations may be laminated. In addition, an electron relay layer may be provided between the p-type layer and the electron injection buffer layer. By forming the charge generation layer 106 using the materials described above, it is possible to suppress the increase in driving voltage when an organic compound layer including an emissive layer is laminated.

[0250] In the charge generation layer 106, when an electron acceptor is added to a hole-transporting material which is an organic compound (p-type layer), the hole-transporting material shown in this embodiment can be used. Examples of electron acceptors include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), chloranil, etc. Other examples include oxides of metals belonging to groups 4 to 8 of the periodic table. Specifically, examples include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide. The acceptor material described above may also be used. Furthermore, the materials constituting the p-type layer may be used as a mixed film, or single films containing each material may be laminated.

[0251] Furthermore, in the charge generation layer 106, if an electron donor is added to the electron transport material (electron injection buffer layer), the electron transport material may be the electron transport material shown in this embodiment.

[0252] Furthermore, alkali metals, alkaline earth metals, rare earth metals, or metals belonging to groups 2 and 13 of the periodic table, as well as their oxides and carbonates, can be used as electron donors. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide (Li2O), cesium carbonate, etc., are preferred. Organic compounds such as tetrathianaphthalene may also be used as electron donors.

[0253] In the charge generation layer 106, when an electron relay layer is provided between the p-type layer and the electron injection buffer layer, the electron relay layer contains at least an electron-transporting material and has the function of preventing interaction between the electron injection buffer layer and the p-type layer and smoothly transferring electrons. Preferably, the LUMO level of the electron-transporting material included in the electron relay layer is between the LUMO level of the acceptor material in the p-type layer and the LUMO level of the electron-transporting material included in the electron transport layer in contact with the charge generation layer 106. The specific energy level of the LUMO level of the electron-transporting material used in the electron relay layer is preferably -5.0 eV or higher, more preferably -5.0 eV or higher and -3.0 eV or lower. Preferably, the electron-transporting material used in the electron relay layer is a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0254] Although Figure 4(D) shows a configuration in which two organic compound layers 103 (organic compound layer 103a and organic compound layer 103b) are stacked, the configuration is not limited to this. For example, by providing a charge generation layer between different light-emitting layers, three or more organic compound layers including light-emitting layers may be stacked.

[0255] ≪Capping layer≫ Although not shown in Figures 4(A) to 4(E), a cap layer may be provided on the second electrode 102 of the light-emitting device. For example, a material with a high refractive index can be used for the cap layer. By providing a cap layer on the second electrode 102, the extraction efficiency of the light emitted from the second electrode 102 can be improved.

[0256] Specific examples of materials that can be used for the cap layer include 5,5'-diphenyl-2,2'-di-5H-[1]benzothieno[3,2-c]carbazole (abbreviated as BisBTc) and 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II).

[0257] Circuit board Furthermore, a light-emitting device according to one aspect of the present invention may be fabricated on a substrate made of glass, plastic, or the like. The order in which the components are fabricated on the substrate may be either by stacking them sequentially from the first electrode 101 side, or by stacking them sequentially from the second electrode 102 side.

[0258] In addition, as a substrate on which a light-emitting device according to one aspect of the present invention can be formed, for example, glass, quartz, or plastic can be used. A flexible substrate may also be used. A flexible substrate is a substrate that can be bent (flexible), and examples include plastic substrates made of polycarbonate or polyarylate. Films, inorganic vapor-deposited films, etc., can also be used. In addition, other materials are acceptable as long as they function as a support in the manufacturing process of the light-emitting device and optical device. Alternatively, any material that has the function of protecting the light-emitting device and optical device is acceptable.

[0259] For example, in this specification, light-emitting devices can be formed using various substrates. The type of substrate is not particularly limited. Examples of substrates include semiconductor substrates (e.g., single-crystal substrates such as silicon substrates), SOI substrates, glass substrates, quartz substrates, plastic substrates, metal substrates, stainless steel substrates, substrates with stainless steel foil, tungsten substrates, substrates with tungsten foil, flexible substrates, laminated films, cellulose nanofibers (CNF) containing fibrous materials, paper, or base films. Examples of glass substrates include barium borosilicate glass, aluminobosilicate glass, or soda-lime glass. Examples of flexible substrates, laminated films, and base films include the following: For example, plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), and polytetrafluoroethylene (PTFE). Alternatively, as an example, acrylic resin. Alternatively, as an example, polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride. Alternatively, examples include resins such as polyamide, polyimide, aramid, or epoxy, inorganic vapor-deposited films, or papers.

[0260] Alternatively, a flexible substrate may be used as the substrate, and the light-emitting device may be formed directly on the flexible substrate. Or, a release layer may be provided between the substrate and the light-emitting device. The release layer can be used to separate the light-emitting device from the substrate after it has been partially or completely completed on it, and to transfer it to another substrate. In this case, the light-emitting device can be transferred to a substrate with poor heat resistance or a flexible substrate. The release layer can be configured in various ways, such as a laminated inorganic film structure of a tungsten film and a silicon oxide film, or a resin film such as polyimide formed on the substrate.

[0261] In other words, a light-emitting device may be formed using one substrate, then the light-emitting device may be transferred to another substrate, and the light-emitting device may be placed on the other substrate. Examples of substrates to which the light-emitting device is transferred include, in addition to the substrates mentioned above, cellophane substrates, stone substrates, wood substrates, cloth substrates (including natural fibers (silk, cotton, linen), synthetic fibers (nylon, polyurethane, polyester), or recycled fibers (acetate, cupro, rayon, recycled polyester), etc.), leather substrates, or rubber substrates. By using these substrates, it is possible to create light-emitting devices that are less prone to breakage, have high heat resistance, are lightweight, or are thin.

[0262] Alternatively, a field-effect transistor (FET), for example, may be formed on the aforementioned substrate, and a light-emitting device may be fabricated on an electrode electrically connected to the FET. This makes it possible to fabricate an active-matrix type display device in which the driving of the light-emitting device is controlled by the FET.

[0263] In this embodiment, one aspect of the present invention has been described. Alternatively, in other embodiments, one aspect of the present invention may be described. However, the aspects of the present invention are not limited to these. In other words, since various aspects of the invention are described in this embodiment and other embodiments, the aspects of the present invention are not limited to a specific aspect. For example, an example of application to a light-emitting device has been shown as one aspect of the present invention, but the aspects of the present invention are not limited to this. For example, depending on the circumstances, one aspect of the present invention may not be applied to a light-emitting device.

[0264] The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

[0265] (Embodiment 2) As illustrated in Figures 5(A) and 5(B), the light-emitting device 130 constitutes a display device formed in multiple locations on the insulating layer 175. In this embodiment, a display device according to one aspect of the present invention will be described in detail.

[0266] The display device 100 has a pixel section 177 in which a plurality of pixels 178 are arranged in a matrix. The pixels 178 include sub-pixels 110R, sub-pixels 110G, and sub-pixels 110B.

[0267] In this specification, when describing matters common to, for example, sub-pixels 110R, 110G, and 110B, they may be referred to simply as sub-pixel 110. Similarly, when describing matters common to other components distinguished by letters, the letters may be omitted and the corresponding symbols used.

[0268] Sub-pixel 110R emits red light, sub-pixel 110G emits green light, and sub-pixel 110B emits blue light. This allows an image to be displayed on the pixel section 177. In this embodiment, three sub-pixels of red (R), green (G), and blue (B) are used as an example, but combinations of other colors of sub-pixels may also be used. Furthermore, the number of sub-pixels is not limited to three, but may be four or more. Examples of four sub-pixels include four sub-pixels of R, G, B, and white (W), four sub-pixels of R, G, B, and yellow (Y), and four sub-pixels of R, G, B, and infrared (IR).

[0269] In this specification and other documents, the row direction is sometimes referred to as the X direction, and the column direction as the Y direction. The X and Y directions intersect, for example, perpendicularly.

[0270] Figure 5(A) shows an example where subpixels of different colors are arranged in the X direction, and subpixels of the same color are arranged in the Y direction. Alternatively, subpixels of different colors may be arranged in the Y direction, and subpixels of the same color may be arranged in the X direction.

[0271] A connecting portion 140 and a region 141 may be provided on the outside of the pixel portion 177. The region 141 is provided between the pixel portion 177 and the connecting portion 140. An organic compound layer 103 is provided in the region 141. A conductive layer 151C is provided in the connecting portion 140.

[0272] Figure 5(A) shows an example where region 141 and connection portion 140 are located to the right of the pixel portion 177, but the positions of region 141 and connection portion 140 are not particularly limited. Also, region 141 and connection portion 140 may be singular or plural.

[0273] Figure 5(B) is an example of a cross-sectional view between the dashed line A1-A2 in Figure 5(A). As shown in Figure 5(B), the display device 100 includes an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and on the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is provided on a substrate (not shown). The insulating layer 175, insulating layer 174, and insulating layer 173 are provided with openings that reach the conductive layer 172, and plugs 176 are provided to fill these openings.

[0274] In the pixel section 177, a light-emitting device 130 is provided on an insulating layer 175 and a plug 176. A protective layer 131 is also provided so as to cover the light-emitting device 130. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. Preferably, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are provided between adjacent light-emitting devices 130.

[0275] In Figure 5(B), multiple cross-sections of the inorganic insulating layer 125 and the insulating layer 127 are shown, but when the display device 100 is viewed from above, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are connected as one unit. In other words, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are insulating layers having an opening on the first electrode.

[0276] Figure 5(B) shows light-emitting devices 130R, 130G, and 130B as light-emitting devices 130. Light-emitting devices 130R, 130G, and 130B emit different colors from each other. For example, light-emitting device 130R can emit red light, light-emitting device 130G can emit green light, and light-emitting device 130B can emit blue light. In addition, light-emitting devices 130R, 130G, or 130B may emit other visible light or infrared light.

[0277] One embodiment of the present invention can be a top-emission type, for example, which emits light in the opposite direction to the substrate on which the light-emitting device is formed. Alternatively, one embodiment of the present invention may be a bottom-emission type.

[0278] Examples of luminescent materials in the light-emitting device 130 include organic compounds or organometallic complexes such as fluorescent compounds, phosphorescent compounds, and thermally activated delayed fluorescence (TADF) materials. Inorganic compounds such as quantum dots may also be used.

[0279] The light-emitting device 130R has the configuration shown in Figure 1(A). It includes a first electrode (pixel electrode) consisting of a conductive layer 151R and a conductive layer 152R, an organic compound layer 103R on the first electrode, a common layer 104 on the organic compound layer 103R, and a second electrode (common electrode) 102 on the common layer 104. The common layer 104 may or may not be provided, but its provision is preferable because it reduces damage to the organic compound layer 103R during processing. If the common layer 104 is provided, it is preferable that the common layer 104 is an electron injection layer. Furthermore, if the common layer 104 is provided, the laminated structure of the organic compound layer 103R and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 1.

[0280] The light-emitting device 130G has the configuration shown in Figure 1(A). It includes a first electrode (pixel electrode) consisting of a conductive layer 151G and a conductive layer 152G, an organic compound layer 103G on the first electrode, a common layer 104 on the organic compound layer 103G, and a second electrode (common electrode) 102 on the common layer 104. The common layer 104 may or may not be provided, but its provision is preferable because it reduces damage to the organic compound layer 103G during processing. If the common layer 104 is provided, it is preferable that the common layer 104 is an electron injection layer. Furthermore, if the common layer 104 is provided, the laminated structure of the organic compound layer 103G and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 1.

[0281] The light-emitting device 130B has the configuration shown in Figure 1(A). It includes a first electrode (pixel electrode) consisting of a conductive layer 151B and a conductive layer 152B, an organic compound layer 103B on the first electrode, a common layer 104 on the organic compound layer 103B, and a second electrode (common electrode) 102 on the common layer 104. The common layer 104 may or may not be provided, but its provision is preferable because it reduces damage to the organic compound layer 103B during processing. If the common layer 104 is provided, it is preferable that the common layer 104 is an electron injection layer. Furthermore, if the common layer 104 is provided, the laminated structure of the organic compound layer 103B and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 1.

[0282] Of the pixel electrodes and common electrodes in a light-emitting device, one functions as the anode and the other as the cathode. In the following explanation, unless otherwise specified, it is assumed that the pixel electrodes function as the anode and the common electrodes function as the cathode.

[0283] The organic compound layers 103R, 103G, and 103B are independently arranged in island-like formations for each sub-pixel or each emission color. By providing the organic compound layer 103 in island-like formations 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 the realization of a display device with extremely high contrast. In particular, it enables the realization of a display device with high current efficiency at low brightness.

[0284] The island-shaped organic compound layers 103 are formed by depositing an EL film and processing the EL film using lithography.

[0285] Furthermore, in a display device according to one aspect of the present invention, it is preferable that the first electrode (pixel electrode) of the light-emitting device be in a stacked configuration. For example, in the example shown in Figure 5(B), the first electrode of the light-emitting device 130 is in a stacked configuration of a conductive layer 151 and a conductive layer 152. For example, when the display device 100 is a top-emission type and the pixel electrode of the light-emitting device 130 functions as an anode, it is preferable that the conductive layer 151 is a layer with high reflectivity for visible light, and the conductive layer 152 is a layer that, for example, transmits visible light and has a large work function. When the display device 100 is a top-emission type, the higher the reflectivity of the pixel electrode for visible light, the higher the efficiency of extracting light emitted by the organic compound layer 103. Also, when the pixel electrode functions as an anode, the larger the work function of the pixel electrode, the easier it is to inject holes into the organic compound layer 103. Based on the above, by making the pixel electrodes of the light-emitting device 130 a stacked structure consisting of a conductive layer 151 with high reflectivity for visible light and a conductive layer 152 with a large work function, the light-emitting device 130 can be made into a light-emitting device with high light extraction efficiency and low driving voltage.

[0286] When the conductive layer 151 is a layer with high reflectivity to visible light, the reflectivity of the conductive layer 151 to visible light is preferably, for example, 40% to 100%, and more preferably, 70% to 100%. Furthermore, when the conductive layer 152 is an electrode that transmits visible light, it is preferable that its transmittance to visible light be, for example, 40% or more.

[0287] In cases where the pixel electrode has a stacked structure consisting of multiple layers, the pixel electrode may be altered due to reactions between these layers, for example. For instance, when a film formed after the pixel electrode is created is removed by a wet etching method, galvanic corrosion may occur when the chemical solution comes into contact with the pixel electrode.

[0288] Therefore, in the display device 100 of this embodiment, an insulating layer 156 is formed on the sides of the conductive layer 151 and the conductive layer 152. This makes it possible to suppress contact of the chemical solution with the conductive layer 151 even when removing a film formed after the formation of a pixel electrode having the conductive layer 151 and the conductive layer 152 by a wet etching method. Consequently, the occurrence of galvanic corrosion on the pixel electrode can be suppressed. As a result, the display device 100 can be manufactured using a method with a high yield, making it a low-cost display device. Furthermore, since the occurrence of defects in the display device 100 can be suppressed, the display device 100 can be a highly reliable display device.

[0289] For example, a metallic 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), neodymium (Nd), and alloys containing these in appropriate combinations can also be used.

[0290] As the conductive layer 152, an oxide having one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, it is preferable to use a conductive oxide containing one or more of the following: indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. In particular, indium tin oxide containing silicon has a large work function, for example, a work function of 4.0 eV or more, so it can be suitably used as the conductive layer 152.

[0291] The conductive layer 151 may be a laminated structure of multiple layers having different materials, and the conductive layer 152 may be a laminated structure of multiple layers having different materials. In this case, the conductive layer 151 may have a layer made of a material that can be used for the conductive layer 152, such as a conductive oxide, and the conductive layer 152 may have a layer made of a material that can be used for the conductive layer 151, such as a metallic material. For example, if the conductive layer 151 has a laminated structure of two or more layers, the layer in contact with the conductive layer 152 may be a layer made of a material that can be used for the conductive layer 152.

[0292] Furthermore, the ends of the insulating layer 156 may have a tapered shape. Specifically, by having the ends of the insulating layer 156 have a tapered shape with a taper angle of less than 90°, the coverage of structures provided along the side surface of the insulating layer 156 can be improved.

[0293] (Embodiment 3) In this embodiment, a light-emitting device according to one aspect of the present invention will be described using Figures 6(A) to 6(G) and Figures 7(A) to 7(I).

[0294] [Pixel layout] This embodiment primarily describes a pixel layout different from that shown in Figure 5(A). There are no particular limitations on the arrangement of subpixels, and various methods can be applied. Examples of subpixel arrangements include stripe arrangements, S-stripe arrangements, matrix arrangements, delta arrangements, Bayer arrangements, and pentile arrangements.

[0295] In this embodiment, the upper surface shape of the sub-pixel shown in the figure corresponds to the upper surface shape of the light-emitting region.

[0296] Examples of the top surface shape of a sub-pixel include polygons such as triangles, quadrilaterals (including rectangles and squares), pentagons, polygons with rounded corners, ellipses, or circles.

[0297] Furthermore, the circuit layout constituting the sub-pixel is not limited to the sub-pixel range shown in the figure, but may be arranged outside of it.

[0298] The pixel 178 shown in Figure 6(A) has an S-stripe array applied to it. The pixel 178 shown in Figure 6(A) is composed of three subpixels: subpixel 110R, subpixel 110G, and subpixel 110B.

[0299] The pixel 178 shown in Figure 6(B) has sub-pixels 110R with a roughly trapezoidal or triangular top surface shape with rounded corners, sub-pixel 110G with a roughly trapezoidal or triangular top surface shape with rounded corners, and sub-pixel 110B with a roughly square or hexagonal top surface shape with rounded corners. Furthermore, sub-pixel 110R has a larger light-emitting area than sub-pixel 110G. In this way, the shape and size of each sub-pixel can be determined independently. For example, sub-pixels with more reliable light-emitting devices can be made smaller in size.

[0300] A Pentile array is applied to pixels 124a and 124b shown in Figure 6(C). Figure 6(C) shows an example in which pixels 124a having sub-pixels 110R and 110G and pixels 124b having sub-pixels 110G and 110B are arranged alternately.

[0301] Pixels 124a and 124b shown in Figures 6(D) to 6(F) are fitted with a delta array. Pixel 124a has two subpixels (subpixels 110R and 110G) in the top row (1st row) and one subpixel (subpixel 110B) in the bottom row (2nd row). Pixel 124b has one subpixel (subpixel 110B) in the top row (1st row) and two subpixels (subpixels 110R and 110G) in the bottom row (2nd row).

[0302] Figure 6(D) shows an example where each subpixel has a roughly quadrilateral top shape with rounded corners, Figure 6(E) shows an example where each subpixel has a circular top shape, and Figure 6(F) shows an example where each subpixel has a roughly hexagonal top shape with rounded corners.

[0303] In Figure 6(F), each subpixel is located inside a densely arranged hexagonal region. When focusing on one subpixel, it is arranged so that it is surrounded by six other subpixels. Furthermore, subpixels that emit light of the same color are not adjacent to each other. For example, when focusing on subpixel 110R, three subpixels 110G and three subpixels 110B are arranged alternately around it.

[0304] Figure 6(G) shows an example where the subpixels of each color are arranged in a zigzag pattern. Specifically, in a top view, the upper edges of two subpixels aligned in the row direction (for example, subpixel 110R and subpixel 110G, or subpixel 110G and subpixel 110B) are offset.

[0305] In each pixel shown in Figures 6(A) to 6(G), it is preferable, for example, that sub-pixel 110R emits red light, sub-pixel 110G emits green light, and sub-pixel 110B emits blue light. However, the configuration of the sub-pixels is not limited to this, and the colors emitted by the sub-pixels and their order can be determined as appropriate. For example, sub-pixel 110G may emit red light, and sub-pixel 110R may emit green light.

[0306] In photolithography, the finer the pattern being processed, the more significant the effects of light diffraction become. This compromises the fidelity of the transfer of the photomask pattern through exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, patterns with rounded corners are likely to be formed. Consequently, the top surface shape of subpixels may be a polygon with rounded corners, an ellipse, or a circle.

[0307] Furthermore, in a method for manufacturing a light-emitting device according to one embodiment of the present invention, an organic compound layer is processed into an island shape using a resist mask. The resist film formed on the organic compound layer needs to be cured at a temperature lower than the heat resistance temperature of the organic compound layer. Therefore, depending on the heat resistance temperature of the organic compound layer material and the curing temperature of the resist material, the curing of the resist film may be insufficient. A resist film that is not sufficiently cured may take a shape that deviates from the desired shape during processing. As a result, the top surface shape of the organic compound layer may become a polygon with rounded corners, an ellipse, or a circle. For example, if an attempt is made to form a resist mask with a square top surface, a resist mask with a circular top surface may be formed, resulting in a circular top surface shape for the organic compound layer.

[0308] Furthermore, in order to achieve the desired shape of the upper surface of the organic compound layer, a technique (OPC (Optical Proximity Correction) technique) may be used to pre-correct the mask pattern so that the design pattern and the transferred pattern match. Specifically, in the OPC technique, for example, a correction pattern is added to the corners of the shape on the mask pattern.

[0309] As shown in Figures 7(A) to 7(I), a pixel can be configured to have four types of subpixels.

[0310] Pixel 178, shown in Figures 7(A) to 7(C), has a stripe arrangement applied to it.

[0311] Figure 7(A) shows an example where each subpixel has a rectangular top surface shape, Figure 7(B) shows an example where each subpixel has a top surface shape formed by connecting two semicircles and a rectangle, and Figure 7(C) shows an example where each subpixel has an elliptical top surface shape.

[0312] Pixel 178, shown in Figures 7(D) to 7(F), has a matrix array applied to it.

[0313] Figure 7(D) shows an example where each subpixel has a square top surface shape, Figure 7(E) shows an example where each subpixel has a roughly square top surface shape with rounded corners, and Figure 7(F) shows an example where each subpixel has a circular top surface shape.

[0314] Figures 7(G) and 7(H) show an example where one pixel 178 is composed of 2 rows and 3 columns.

[0315] Pixel 178, shown in Figure 7(G), has three subpixels (subpixels 110R, 110G, and 110B) in the top row (row 1) and one subpixel (subpixel 110W) in the bottom row (row 2). In other words, pixel 178 has subpixel 110R in the left column (column 1), subpixel 110G in the middle column (column 2), subpixel 110B in the right column (column 3), and subpixel 110W across these three columns.

[0316] Pixel 178, shown in Figure 7(H), has three sub-pixels (sub-pixels 110R, 110G, and 110B) in the top row (1st row) and three sub-pixels 110W in the bottom row (2nd row). In other words, pixel 178 has sub-pixels 110R and 110W in the left column (1st column), sub-pixels 110G and 110W in the middle column (2nd column), and sub-pixels 110B and 110W in the right column (3rd column). As shown in Figure 7(H), by aligning the arrangement of sub-pixels in the top row and bottom row, it becomes possible to efficiently remove dust that may be generated during the manufacturing process, for example. Therefore, a light-emitting device with high display quality can be provided.

[0317] In pixel 178 shown in Figures 7(G) and 7(H), the layout of sub-pixels 110R, 110G, and 110B is in a stripe arrangement, which improves the display quality.

[0318] Figure 7(I) shows an example where one pixel, 178, is composed of 3 rows and 2 columns.

[0319] Pixel 178, shown in Figure 7(I), has sub-pixel 110R in the top row (1st row), sub-pixel 110G in the middle row (2nd row), sub-pixel 110B spanning from the 1st to the 2nd row, and one sub-pixel (sub-pixel 110W) in the bottom row (3rd row). In other words, pixel 178 has sub-pixels 110R and 110G in the left column (1st column), sub-pixel 110B in the right column (2nd column), and sub-pixel 110W spanning these two columns.

[0320] In pixel 178 shown in Figure 7(I), the layout of sub-pixels 110R, 110G, and 110B forms a so-called S-stripe arrangement, which improves display quality.

[0321] The pixel 178 shown in Figures 7(A) to 7(I) is composed of four subpixels: subpixel 110R, subpixel 110G, subpixel 110B, and subpixel 110W. For example, subpixel 110R may be a subpixel that emits red light, subpixel 110G may be a subpixel that emits green light, subpixel 110B may be a subpixel that emits blue light, and subpixel 110W may be a subpixel that emits white light. At least one of subpixels 110R, 110G, 110B, and 110W may be a subpixel that emits cyan light, magenta light, yellow light, or near-infrared light.

[0322] As described above, the light-emitting device according to one aspect of the present invention can be configured to apply various layouts to pixels that consist of subpixels having light-emitting devices.

[0323] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, these configuration examples can be appropriately combined.

[0324] (Embodiment 4) This embodiment describes a display device according to one aspect of the present invention.

[0325] The display device of this embodiment can be a high-definition display device. Therefore, the display device of this embodiment can be used, for example, as a display unit for information terminals (wearable devices) such as wristwatches and bracelets, and as a display unit for wearable devices that can be worn on the head, such as VR devices such as head-mounted displays (HMDs) and AR devices such as glasses.

[0326] Furthermore, the display device of this embodiment can be a high-resolution display device or a large-screen display device. Therefore, the display device of this embodiment can be used in electronic devices with relatively large screens, such as television equipment, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal information terminals, and audio playback devices.

[0327] [Display Module] Figure 8(A) shows a perspective view of the 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 display device 100A, but may be any of the display devices 100B, 100C, 100D, 100D2, 100E, or 100E2 described later.

[0328] The display module 280 has substrates 291 and 292. The display module 280 has a display unit 281. The display unit 281 is an area in the display module 280 that displays an image, and is an area in which light from each pixel provided in the pixel unit 284, which will be described later, can be seen.

[0329] Figure 8(B) shows a schematic perspective view illustrating the configuration of the substrate 291. On the substrate 291, a circuit section 282, a pixel circuit section 283 on the circuit section 282, and a pixel section 284 on the pixel circuit section 283 are stacked. In addition, a terminal section 285 for connecting to the FPC 290 is provided in the portion of the substrate 291 that does not overlap with the pixel section 284. The terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286 composed of multiple wires.

[0330] The pixel section 284 has a plurality of pixels 284a arranged periodically. A magnified view of one pixel 284a is shown on the right side of Figure 8(B). Various configurations described in the previous embodiment can be applied to the pixels 284a.

[0331] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0332] One pixel circuit 283a is a circuit that controls the driving of multiple devices that a single pixel 284a possesses.

[0333] The circuit section 282 has circuits for driving each pixel circuit 283a of the pixel circuit section 283. For example, it is preferable to have one or both of a gate line drive circuit and a source line drive circuit. In addition, it may have at least one of the following: an arithmetic circuit, a memory circuit, and a power supply circuit.

[0334] The FPC290 functions as wiring for supplying video signals or power potential, etc., to the circuit section 282 from an external source. An IC may also be mounted on the FPC290.

[0335] The display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are superimposed on the lower side of the pixel section 284, thereby making it possible to achieve an extremely high aperture ratio (effective display area ratio) of the display section 281.

[0336] Because such a display module 280 is extremely high-resolution, it can be suitably used in VR devices such as HMDs or AR devices such as glasses. For example, even in a configuration where the display part of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display part 281, so even when the display part is magnified with lenses, pixels are not visible, and a highly immersive display can be achieved. Furthermore, the display module 280 is not limited to this and can be suitably used in electronic devices having relatively small display parts.

[0337] [Display device 100A] The display device 100A shown in Figure 9(A) includes a substrate 301, light-emitting devices 130R, 130G, 130B, a capacitor 240, and a transistor 310.

[0338] Substrate 301 corresponds to substrate 291 in Figures 8(A) and 8(B). Transistor 310 is a transistor having a channel formation region in substrate 301. For substrate 301, a semiconductor substrate such as a single-crystal silicon substrate can be used. Transistor 310 has a part of substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region of substrate 301 doped with impurities and functions as a source or drain. The insulating layer 314 is provided covering the side surface of the conductive layer 311.

[0339] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0340] Furthermore, an insulating layer 261 is provided covering the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0341] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located between them. The conductive layer 241 acts as one electrode of the capacitor 240, the conductive layer 245 acts as the other electrode of the capacitor 240, and the insulating layer 243 acts as the dielectric of the capacitor 240.

[0342] The conductive layer 241 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is electrically connected to either the source or drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided covering the conductive layer 241. The conductive layer 245 is provided in the region that overlaps with the conductive layer 241 via the insulating layer 243.

[0343] An insulating layer 255 is provided covering the capacitance 240, an insulating layer 174 is provided on the insulating layer 255, and an insulating layer 175 is provided on the insulating layer 174. Light-emitting devices 130R, 130G, and 130B are provided on the insulating layer 175. An insulator is provided in the region between adjacent light-emitting devices.

[0344] An insulating layer 156R is provided so as to cover the side surface of the conductive layer 151R, an insulating layer 156G is provided so as to cover the side surface of the conductive layer 151G, and an insulating layer 156B is provided so as to cover the side surface of the conductive layer 151B. Furthermore, a conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R, a conductive layer 152G is provided so as to cover the conductive layer 151G and the insulating layer 156G, and a conductive layer 152B is provided so as to cover the conductive layer 151B and the insulating layer 156B. A sacrificial layer 158R is located on the organic compound layer 103R, a sacrificial layer 158G is located on the organic compound layer 103G, and a sacrificial layer 158B is located on the organic compound layer 103B.

[0345] The conductive layers 151R, 151G, and 151B are electrically connected to either the source or drain of the transistor 310 by the insulating layers 243, 255, 174, and plugs 256 embedded in the insulating layer 175, the conductive layer 241 embedded in the insulating layer 254, and plugs 271 embedded in the insulating layer 261. Various conductive materials can be used for the plugs.

[0346] Furthermore, a protective layer 131 is provided on the light-emitting devices 130R, 130G, and 130B. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. Details of the components from the light-emitting device 130 to the substrate 120 can be found in the embodiments described above. The substrate 120 corresponds to the substrate 292 in Figure 8(A).

[0347] Figure 9(B) shows a modified version of the display device 100A shown in Figure 9(A). The display device shown in Figure 9(B) has a colored layer 132R, a colored layer 132G, and a colored layer 132B, and the light-emitting device 130 has a region that overlaps with one of the colored layers 132R, 132G, and 132B. In the display device shown in Figure 9(B), the light-emitting device 130 can emit, for example, white light. Also, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light.

[0348] [Display device 100B] Figure 10 shows a perspective view of the display device 100B, and Figure 11 shows a cross-sectional view of the display device 100C.

[0349] The display device 100B has a configuration in which substrate 352 and substrate 351 are bonded together. In Figure 10, substrate 352 is shown by a dashed line.

[0350] The display device 100B includes a pixel section 177, a connection section 140, a circuit 356, and wiring 355, etc. Figure 10 shows an example in which IC 354 and FPC 353 are mounted on the display device 100B. Therefore, the configuration shown in Figure 10 can also be called a display module having the display device 100B, an IC (integrated circuit), and an FPC. Here, a display module is a display device on which a connector such as an FPC is attached, or on which an IC is mounted.

[0351] The connection portion 140 is provided on the outside of the pixel portion 177. There may be one or more connection portions 140. The connection portion 140 is electrically connected to the common electrode of the light-emitting device and the conductive layer, and can supply potential to the common electrode.

[0352] For example, a scan line drive circuit can be used as circuit 356.

[0353] The wiring 355 has the function of supplying signals and power to the pixel unit 177 and the circuit 356. These signals and power are input to the wiring 355 from an external source via the FPC 353 and IC 354.

[0354] Figure 10 shows an example in which IC 354 is provided on substrate 351 using COG (Chip On Glass) or COF (Chip On Film) methods. IC 354 can be an IC having, for example, a scan line drive circuit or a signal line drive circuit. Note that the display device 100B and the display module may be configured without an IC. Alternatively, the IC may be mounted on an FPC, for example, using the COF method.

[0355] Figure 11 shows an example of a cross-section of the display device 100C, obtained by cutting a portion of the region including the FPC 353, a portion of the circuit 356, a portion of the pixel portion 177, a portion of the connection portion 140, and a portion of the region including the end portion of the display device 100B in Figure 10.

[0356] [Display device 100C] The display device 100C shown in Figure 11 has a transistor 201, a transistor 205, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, and a light-emitting device 130B that emits blue light, etc., between substrates 351 and 352.

[0357] Details of the light-emitting devices 130R, 130G, and 130B can be found in the embodiments described above.

[0358] Light-emitting device 130R has a conductive layer 224R, a conductive layer 151R on the conductive layer 224R, and a conductive layer 152R on the conductive layer 151R. Light-emitting device 130G has a conductive layer 224G, a conductive layer 151G on the conductive layer 224G, and a conductive layer 152G on the conductive layer 151G. Light-emitting device 130B has a conductive layer 224B, a conductive layer 151B on the conductive layer 224B, and a conductive layer 152B on the conductive layer 151B.

[0359] The conductive layer 224R is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The edge of the conductive layer 151R is located outside the edge of the conductive layer 224R. The insulating layer 156R is provided so as to have a region in contact with the side surface of the conductive layer 151R, and the conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R.

[0360] The conductive layers 224G, 151G, 152G, and insulating layer 156G in the light-emitting device 130G, and the conductive layers 224B, 151B, 152B, and insulating layer 156B in the light-emitting device 130B are the same as the conductive layers 224R, 151R, 152R, and insulating layer 156R in the light-emitting device 130R, so a detailed explanation is omitted.

[0361] The conductive layer 224R, conductive layer 224G, and conductive layer 224B have recesses formed to cover the openings provided in the insulating layer 214. Layer 128 is embedded in these recesses.

[0362] Layer 128 has the function of filling and flattening the recesses of conductive layers 224R, 224G, and 224B. Conductive layers 151R, 151G, and 151B are provided on conductive layers 224R, 224G, and 224B and on layer 128, and are electrically connected to conductive layers 224R, 224G, and 224B. Therefore, regions overlapping with the recesses of conductive layers 224R, 224G, and 224B can also be used as light-emitting regions, thereby increasing the aperture ratio of the pixels.

[0363] Layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used for layer 128 as appropriate. In particular, it is preferable that layer 128 be formed using an insulating material, and especially preferable that it be formed using an organic insulating material. For example, an organic insulating material that can be used for the insulating layer 127 described above can be applied to layer 128.

[0364] A protective layer 131 is provided on the light-emitting devices 130R, 130G, and 130B. The protective layer 131 and the substrate 352 are bonded via an adhesive layer 142. A light-shielding layer 157 is provided on the substrate 352. A solid encapsulation structure or a hollow encapsulation structure can be applied to encapsulate the light-emitting devices 130. In Figure 11, the space between the substrate 352 and the substrate 351 is filled with the adhesive layer 142, indicating a solid encapsulation structure. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), indicating a hollow encapsulation structure. In this case, the adhesive layer 142 may be provided in a frame shape so as not to overlap with the light-emitting devices. Furthermore, the space may be filled with a resin different from the adhesive layer 142 provided in a frame shape.

[0365] Figure 11 shows an example in which the connection portion 140 has a conductive layer 224C obtained by processing the same conductive film as conductive layers 224R, 224G, and 224B; a conductive layer 151C obtained by processing the same conductive film as conductive layers 151R, 151G, and 151B; and a conductive layer 152C obtained by processing the same conductive film as conductive layers 152R, 152G, and 152B. Figure 11 also shows an example in which an insulating layer 156C is provided so as to cover the side surface of conductive layer 151C.

[0366] The display device 100C is a top-emission type. The light emitted by the light-emitting device is emitted towards the substrate 352. It is preferable to use a material with high transmittance to visible light for the substrate 352. The pixel electrodes contain a material that reflects visible light, and the counter electrodes (common electrodes 155) contain a material that transmits visible light.

[0367] On the substrate 351, insulating layers 211, 213, 215, and 214 are provided in this order. A portion of insulating layer 211 functions as a gate insulating layer for each transistor. A portion of insulating layer 213 functions as a gate insulating layer for each transistor. Insulating layer 215 is provided covering the transistors. Insulating layer 214 is provided covering the transistors and functions as a planarization layer. The number of gate insulating layers and insulating layers covering the transistors are not limited and may be a single layer or two or more layers, respectively.

[0368] It is preferable to use an inorganic insulating film as the insulating layer 211, insulating layer 213, and insulating layer 215, respectively.

[0369] An organic insulating layer is preferred for the insulating layer 214, which functions as a planarizing layer.

[0370] Transistors 201 and 205 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as source and drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate.

[0371] A connection portion 204 is provided in the region of substrate 351 that does not overlap with substrate 352. At the connection portion 204, the source electrode or drain electrode of transistor 201 is electrically connected to FPC 353 via conductive layer 166 and connection layer 242. The conductive layer 166 is shown as an example of a laminated structure consisting of a conductive film obtained by processing the same conductive film as conductive layers 224R, 224G, and 224B, a conductive film obtained by processing the same conductive film as conductive layers 151R, 151G, and 151B, and a conductive film obtained by processing the same conductive film as conductive layers 152R, 152G, and 152B. On the upper surface of the connection portion 204, the conductive layer 166 is exposed. This allows the connection portion 204 and FPC 353 to be electrically connected via the connection layer 242.

[0372] It is preferable to provide a light-shielding layer 157 on the surface of the substrate 352 that faces the substrate 351. The light-shielding layer 157 can be provided between adjacent light-emitting devices, at connection points 140, and in circuits 356, etc. In addition, various optical components can be arranged on the outside of the substrate 352.

[0373] Materials that can be used for substrate 120 can be applied to substrate 351 and substrate 352, respectively.

[0374] As the adhesive layer 142, a material that can be used for the resin layer 122 can be applied.

[0375] As the connecting layer 242, an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP) can be used.

[0376] [Display device 100D] The display device 100D shown in Figure 12 differs from the display device 100C shown in Figure 11 mainly in that it is a bottom-emission type display device.

[0377] The light emitted by the light-emitting device is projected onto the substrate 351. It is preferable to use a material with high transparency to visible light for the substrate 351. On the other hand, the light transmittance of the material used for the substrate 352 is not a requirement.

[0378] It is preferable to form a light-shielding layer 317 between the substrate 351 and the transistor 201, and between the substrate 351 and the transistor 205. Figure 12 shows an example in which a light-shielding layer 317 is provided on the substrate 351, an insulating layer 153 is provided on the light-shielding layer 317, and transistors 201, 205, etc. are provided on the insulating layer 153.

[0379] 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.

[0380] 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.

[0381] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are made of materials with high transmittance to visible light. It is preferable to use a material that reflects visible light for the second electrode 102.

[0382] Although the light-emitting device 130G is not shown in Figure 12, it is also provided.

[0383] Furthermore, while Figure 12 and other figures show an example where the upper surface of layer 128 has a flat portion, the shape of layer 128 is not particularly limited.

[0384] [Display device 100D2] The display device 100D2 shown in Figure 13(A) is an example of a bottom-emission type display device, different from the display device 100D shown in Figure 12. The display device 100D2 differs from the display device 100D in that it has an organic resin layer 180. Note that in the figure, the reference numerals for components that are the same as in Figure 12 may be omitted, and details can be found in the description in Figure 12.

[0385] Furthermore, Figure 13(B) shows the top view layout of pixels 178 (pixels 178a and 178b) having sub-pixels 110 (sub-pixels 110R, 110G, 110B, and 110W), and Figure 13(C) shows the top view of the organic resin layer 180 in the region where sub-pixels 110R and 110W of pixel 178 are formed. The width between the light-shielding layers 317 is the width 110Rw in the light-emitting region of sub-pixel 110R.

[0386] As shown in Figure 13(A), the organic resin layer 180 is provided on the insulating layer 214. As shown in the region enclosed by the dashed line in Figure 13(A) and in Figure 13(C), the organic resin layer 180 has curved recesses 181 (recesses 181a, recesses 181b) in at least the region where subpixels are formed. Recesses 181 may also be provided outside the light-emitting region, such as recess 181c. By providing recess 181c, the light emitted in the region overlapping with the light-shielding layer 317 or the light that has traveled to the region overlapping with the light-shielding layer 317 can be refracted and extracted from the light-emitting region, thereby improving the luminescence efficiency.

[0387] Multiple recesses 181 may be formed in a matrix. Recesses 181a and 181b may be in contact with each other, or they may have a plane between them.

[0388] Furthermore, in Figure 13, the top surface shape of the recess is shown as a hexagon (Figure 13(C)) and the cross-sectional shape as a semicircle (Figure 13(A)), but other shapes may be used as needed. For example, the top surface shape of the recess may be a triangle, a quadrilateral (including rectangles and squares), a pentagon or other polygon, a polygon with rounded corners, an ellipse, or a circle.

[0389] As the organic resin layer 180, an insulating layer having an organic material can be used. For example, as the organic resin layer 180, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be used. Alternatively, as the organic resin layer 180, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin may be used.

[0390] Furthermore, a photosensitive resin can be used as the organic resin layer 180. A photoresist may be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0391] The organic resin layer 180 may contain a material that absorbs visible light. For example, the organic resin layer 180 itself may be composed of a material that absorbs visible light, or the organic resin layer 180 may contain a pigment that absorbs visible light. As the organic resin layer 180, for example, a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light, or a resin that contains carbon black as a pigment and functions as a black matrix can be used.

[0392] Furthermore, the organic resin layer 180 has a first electrode 101 (first electrode 101R and first electrode 101W), and the first electrode 101 has an organic compound layer 103. The ends of the first electrode 101 and the organic compound layer 103 may be covered with an insulating layer 127.

[0393] Furthermore, the first electrode 101, formed on the organic resin layer 180, has recesses along with the recesses of the organic resin layer 180. Additionally, the organic compound layer 103, formed on the first electrode 101, has recesses along with the recesses of the first electrode 101. Furthermore, the common layer 104, formed on the organic compound layer 103, has recesses along with the recesses of the organic compound layer 103. Finally, the second electrode 102, formed on the common layer 104, has recesses along with the recesses of the common layer 104. In other words, the recesses of the organic resin layer 180, the first electrode 101, the organic compound layer 103, the common layer 104, and the second electrode 102 have a structure in which they overlap each other.

[0394] Furthermore, a common layer 104 is provided on the organic compound layer 103 and the insulating layer 127, and a second electrode 102 is provided on the common layer 104. A protective layer 131 is provided on the second electrode 102, and the structure is bonded to the substrate 352 via an adhesive layer 142.

[0395] Although Figure 13 does not show the light-emitting devices 130G and 130B, they are also provided.

[0396] [Display device 100E] The display device 100E shown in Figure 14 is a modified version of the display device 100C shown in Figure 11, and differs from the display device 100C mainly in that it has a colored layer 132R, a colored layer 132G, and a colored layer 132B.

[0397] In the display device 100E, the light-emitting device 130 has a region that overlaps with one of the colored layers 132R, 132G, and 132B. The colored layers 132R, 132G, and 132B can be provided on the substrate 351 side of the substrate 352. The edges of the colored layer 132R, the edges of the colored layer 132G, and the edges of the colored layer 132B can overlap with the light-shielding layer 157.

[0398] In the display device 100E, the light-emitting device 130 can emit, for example, white light. Furthermore, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light. The display device 100E may also be configured with the colored layers 132R, 132G, and 132B placed between the protective layer 131 and the adhesive layer 142.

[0399] [Display device 100E2] The display device 100E2 shown in Figure 15(A) is a modified version of the display device 100E shown in Figure 14, and has a microlens 182 on the colored layer 132R, colored layer 132G, and colored layer 132B. Note that in the figure, the reference numerals for components that are the same as in Figure 14 may be omitted, and details can be found in the description in Figure 14.

[0400] Furthermore, Figure 15(B) shows the top view layout of pixel 178 (pixels 178a and 178b) having sub-pixels 110 (sub-pixels 110R, 110G, and 110B), and Figure 15(C) shows the top view of the microlens 182 in the region where sub-pixels 110R, 110G, and 110B of pixel 178 are formed. The region where the common electrode 155 and the organic compound layer 103 are in contact is the width 110Gw of the light-emitting region of sub-pixel 110G.

[0401] The display device 100E2 shown in Figure 15(A) has a planarization film 143 on a protective layer 131, and a colored layer 132R, a colored layer 132G, and a colored layer 132B on the planarization film 143. A planarization film 144 is provided so as to cover the colored layers 132R, 132G, and 132B. A microlens 182 is provided on the planarization film 144.

[0402] Furthermore, as shown in Figure 15(C), the microlenses 182 may be provided for each sub-pixel in the region where the sub-pixels are formed.

[0403] In Figure 15(C), the top surface shape of the microlens 182 is shown as a hexagon, but other shapes may be used as needed. For example, the top surface shape of the microlens 182 may be a triangle, a quadrilateral (including rectangles and squares), a pentagon, or other polygons, a polygon with rounded corners, an ellipse, or a circle.

[0404] The microlens 182 can be formed using the same material as the organic resin layer 180.

[0405] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, these configuration examples can be appropriately combined.

[0406] (Embodiment 5) This embodiment describes an electronic device according to one aspect of the present invention.

[0407] The electronic device of this embodiment has a light-emitting device according to one aspect of the present invention in its display unit. The light-emitting device according to one aspect of the present invention is highly reliable and easily capable of high-definition and high-resolution displays. Therefore, it can be used in the display units of various electronic devices.

[0408] Examples of electronic devices include television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko 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, personal digital assistants, and audio playback devices.

[0409] In particular, since the light-emitting device according to one aspect of the present invention can increase resolution, it can be suitably used in electronic devices having a relatively small display area. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), as well as wearable devices that can be worn on the head, such as VR devices such as head-mounted displays, AR devices such as glasses, and MR (Mixed Reality) devices.

[0410] A light-emitting device according to one aspect of the present invention preferably has an extremely high resolution such as HD (1280 x 720 pixels), FHD (1920 x 1080 pixels), WQHD (2560 x 1440 pixels), WQXGA (2560 x 1600 pixels), 4K (3840 x 2160 pixels), or 8K (7680 x 4320 pixels). In particular, a resolution of 4K, 8K, or higher is preferred. Furthermore, the pixel density (resolution) of the light-emitting device according to one aspect of the present invention is preferably 100 ppi or more, preferably 300 ppi or more, more preferably 500 ppi or more, more preferably 1000 ppi or more, more preferably 2000 ppi or more, more preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 7000 ppi or more. By using a light-emitting device that has either high resolution or high detail, or both, it becomes possible to further enhance the sense of presence and depth. Furthermore, there are no particular limitations on the aspect ratio of the light-emitting device according to one embodiment of the present invention. For example, the light-emitting device can support various aspect ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0411] The electronic device of this embodiment may have sensors (including those with the function of detecting, detecting, or measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation).

[0412] The electronic device of this embodiment can have a variety of functions. For example, it can have a function to display various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function to display a calendar, date or time, a function to execute various software (programs), a wireless communication function, a function to read programs or data recorded on a recording medium, and so on.

[0413] Figures 16(A) to 16(D) illustrate an example of a wearable device that can be worn on the head. These wearable devices have at least one of the following functions: a function to display AR content, a function to display VR content, a function to display SR (Substitutional Reality) content, and a function to display MR content. By having an electronic device that has the function to display at least one of the following content types, such as AR, VR, SR, and MR, it is possible to enhance the user's sense of immersion.

[0414] The electronic device 700A shown in Figure 16(A) and the electronic device 700B shown in Figure 16(B) each 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 members 753, a frame 757, and a pair of nose pads 758.

[0415] A light-emitting device according to one embodiment of the present invention can be applied to the display panel 751. Therefore, a highly reliable electronic device can be made.

[0416] Electronic devices 700A and 700B can project an image displayed on the display panel 751 onto the display area 756 of the optical element 753. Because the optical element 753 is translucent, the user can see the image displayed on the display area superimposed on the transmitted image visible through the optical element 753. Therefore, electronic devices 700A and 700B are electronic devices capable of AR display.

[0417] Electronic devices 700A and 700B may be equipped with cameras capable of capturing images of the area in front of them as imaging units. Furthermore, electronic devices 700A and 700B may each be equipped with acceleration sensors such as gyro sensors to detect the orientation of the user's head and display an image corresponding to that orientation in the display area 756.

[0418] The communications unit has a wireless communication device, which can supply, for example, a video signal. Alternatively, instead of the wireless communication device, or in addition to the wireless communication device, it may be equipped with a connector to which a cable for supplying video signals and power potential can be connected.

[0419] Furthermore, electronic devices 700A and 700B are equipped with batteries that can be charged wirelessly, wired, or both.

[0420] The housing 721 may be equipped with a touch sensor module. The touch sensor module has the function of detecting when the outer surface of the housing 721 is touched. The touch sensor module can detect the user's tap or slide operations and perform various processes. For example, a tap operation can be used to pause or resume the video, and a slide operation can be used to fast forward or rewind. Furthermore, by providing a touch sensor module in each of the two housings 721, the range of operations can be expanded.

[0421] Various types of touch sensors can be applied to the touch sensor module. For example, various methods such as capacitive, resistive, infrared, electromagnetic induction, surface acoustic wave, or optical sensors can be used. In particular, it is preferable to apply capacitive or optical sensors to the touch sensor module.

[0422] When using an optical touch sensor, a photoelectric conversion device (also called a photoelectric conversion element) can be used as the light-receiving device. The active layer of the photoelectric conversion device can be made of either an inorganic semiconductor or an organic semiconductor, or both.

[0423] The electronic device 800A shown in Figure 16(C) and the electronic device 800B shown in Figure 16(D) each include a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0424] A light-emitting device according to one embodiment of the present invention can be applied to the display unit 820. Therefore, a highly reliable electronic device can be made.

[0425] The display unit 820 is located inside the housing 821, in a position where it can be seen through the lens 832. Furthermore, by displaying different images on a pair of display units 820, a three-dimensional display using parallax can also be performed.

[0426] Electronic devices 800A and 800B can be described as electronic devices for VR. A user wearing either electronic device 800A or electronic device 800B can view the image displayed on the display unit 820 through the lens 832.

[0427] It is preferable that electronic devices 800A and 800B each have a mechanism that allows the left and right positions of the lens 832 and the display unit 820 to be optimally positioned according to the user's eye position. It is also preferable that they have a mechanism that adjusts the focus by changing the distance between the lens 832 and the display unit 820.

[0428] The attachment portion 823 allows the user to attach the electronic device 800A or 800B to their head. Note that, for example, in Figure 16(C), it is illustrated as having a shape similar to the temples (or arms, etc.) of eyeglasses, but is not limited to this. The attachment portion 823 only needs to be wearable by the user; for example, it may be helmet-shaped or band-shaped.

[0429] 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. In addition, multiple cameras may be provided to support multiple angles of view, such as telephoto and wide-angle.

[0430] Although an example with an imaging unit 825 is shown here, any distance measuring sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object can be provided. In other words, the imaging unit 825 is one form of a detection unit. As the detection unit, for example, an image sensor or a distance image sensor such as LiDAR (Light Detection and Ranging) can be used. By using the image obtained by the camera and the image obtained by the distance image sensor, more information can be acquired, enabling more accurate gesture control.

[0431] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone. For example, a configuration having such a vibration mechanism can be applied to one or more of the display unit 820, housing 821, and mounting unit 823. This allows users to enjoy video and audio simply by wearing the electronic device 800A, without needing separate audio equipment such as headphones, earphones, or speakers.

[0432] Electronic devices 800A and 800B may each have input terminals. Cables can be connected to the input terminals to supply video signals from video output devices, etc., and power for charging batteries provided within the electronic devices.

[0433] An electronic device according to one aspect of the present invention may have a function for wireless communication with an earphone 750. The earphone 750 has a communication unit (not shown) and has a wireless communication function. The earphone 750 can receive information (e.g., voice data) from the electronic device through its wireless communication function. For example, the electronic device 700A shown in Figure 16(A) has a function for transmitting information to the earphone 750 through its wireless communication function. Also, for example, the electronic device 800A shown in Figure 16(C) has a function for transmitting information to the earphone 750 through its wireless communication function.

[0434] Furthermore, the electronic device may have an earphone section. The electronic device 700B shown in Figure 16(B) has an earphone section 727. For example, the earphone section 727 and the control unit can be connected to each other by a wire. Part of the wiring connecting the earphone section 727 and the control unit may be located inside the housing 721 or the mounting section 723.

[0435] Similarly, the electronic device 800B shown in Figure 16(D) has an earphone unit 827. For example, the earphone unit 827 and the control unit 824 can be connected to each other by a wire. Part of the wiring connecting the earphone unit 827 and the control unit 824 may be located inside the housing 821 or the mounting unit 823. Also, the earphone unit 827 and the mounting unit 823 may have magnets. This allows the earphone unit 827 to be fixed to the mounting unit 823 by magnetic force, making storage easier and preferable.

[0436] Furthermore, the electronic device may have an audio output terminal to which earphones or headphones can be connected. The electronic device may also have an audio input terminal and / or an audio input mechanism. For example, a microphone or other sound-collecting device can be used as the audio input mechanism. By having an audio input mechanism, the electronic device may be given the function of a so-called headset.

[0437] Thus, as one embodiment of the present invention, both eyeglass-type (electronic devices 700A and 700B, etc.) and goggle-type (electronic devices 800A and 800B, etc.) are preferred as electronic devices.

[0438] Furthermore, an electronic device according to one aspect of the present invention can transmit information to earphones via wired or wireless means.

[0439] The electronic device 6500 shown in Figure 17(A) is a portable information terminal that can be used as a smartphone.

[0440] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508, etc. The display unit 6502 has a touch panel function.

[0441] A light-emitting device according to one embodiment of the present invention can be applied to the display unit 6502. Therefore, a highly reliable electronic device can be made.

[0442] Figure 17(B) is a schematic cross-sectional view of the housing 6501 including the end on the microphone 6506 side.

[0443] A light-transmitting protective member 6510 is provided on the display side of the housing 6501, and the display panel 6511, optical member 6512, touch sensor panel 6513, printed circuit board 6517, and battery 6518 are arranged in the space enclosed by the housing 6501 and the protective member 6510.

[0444] The protective member 6510 is fixed to the display panel 6511, the optical member 6512, and the touch sensor panel 6513 by an adhesive layer (not shown).

[0445] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and the FPC 6515 is connected to this folded portion. IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals provided on the printed circuit board 6517.

[0446] A light-emitting device according to one embodiment of the present invention can be applied to the display panel 6511. This makes it possible to realize an extremely lightweight electronic device. Furthermore, because the display panel 6511 is extremely thin, it is possible to incorporate a large-capacity battery 6518 while keeping the thickness of the electronic device low. In addition, by folding back a part of the display panel 6511 and placing the connection part with the FPC 6515 on the back of the pixel section, an electronic device with a narrow bezel can be realized.

[0447] Figure 17(C) shows an example of a television system. The television system 7100 has a display unit 7000 incorporated into a housing 7171. Here, the housing 7171 is shown supported by a stand 7173.

[0448] A light-emitting device according to one embodiment of the present invention can be applied to the display unit 7000. Therefore, a highly reliable electronic device can be made.

[0449] The television device 7100 shown in Figure 17(C) can be operated using the operation switches on the housing 7171 and a separate remote control unit 7151. Alternatively, the display unit 7000 may be equipped with a touch sensor, and the television device 7100 can be operated by touching the display unit 7000 with a finger or the like. The remote control unit 7151 may have a display unit that displays information output from the remote control unit 7151. Channels and volume can be controlled and the image displayed on the display unit 7000 can be controlled using the operation keys or touch panel on the remote control unit 7151.

[0450] The television system 7100 is configured to include a receiver and a modem. The receiver can receive general television broadcasts. Furthermore, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0451] Figure 17(D) shows an example of a notebook personal computer. The notebook personal computer 7200 has a casing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214, etc. A display unit 7000 is incorporated into the casing 7211.

[0452] A light-emitting device according to one embodiment of the present invention can be applied to the display unit 7000. Therefore, a highly reliable electronic device can be made.

[0453] Figures 17(E) and 17(F) show examples of digital signage.

[0454] The digital signage 7300 shown in Figure 17(E) comprises a housing 7301, a display unit 7000, and a speaker 7303, etc. Furthermore, it may include LED lamps, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc.

[0455] Figure 17(F) shows a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 has a display unit 7000 that is provided along the curved surface of the column 7401.

[0456] In Figures 17(E) and 17(F), a light-emitting device according to one embodiment of the present invention can be applied to the display unit 7000. Therefore, a highly reliable electronic device can be made.

[0457] The larger the display area 7000, the more information can be provided at once. Furthermore, a larger display area 7000 is more eye-catching, which can, for example, enhance the effectiveness of advertising.

[0458] Applying a touch panel to the display unit 7000 is preferable because it not only displays images or videos on the display unit 7000, but also allows users to operate it intuitively. Furthermore, when used for purposes such as providing route information or traffic information, intuitive operation can enhance usability.

[0459] Furthermore, as shown in Figures 17(E) and 17(F), it is preferable that the digital signage 7300 or digital signage 7400 can be linked wirelessly with an information terminal 7311 or information terminal 7411 such as a smartphone owned by the user. For example, the advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or information terminal 7411. Also, the display on the display unit 7000 can be switched by operating the information terminal 7311 or information terminal 7411.

[0460] Furthermore, the digital signage 7300 or digital signage 7400 can be used to run games using the screen of the information terminal 7311 or information terminal 7411 as the control device (controller). This allows an unspecified number of users to participate in and enjoy the game simultaneously.

[0461] The electronic equipment shown in Figures 18(A) to 18(G) includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), connection terminals 9006, sensors 9007 (including functions for detecting, detecting, or measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation), a microphone 9008, etc.

[0462] The electronic devices shown in Figures 18(A) to 18(G) have various functions. For example, they may have functions to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date or time, a function to control processing by various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. However, the functions of electronic devices are not limited to these and can have various functions. Electronic devices may have multiple display units. Furthermore, electronic devices may be equipped with a camera, etc., and have functions to capture still images or videos and save them to a recording medium (external or built into the camera), a function to display the captured images on a display unit, etc.

[0463] The details of the electronic equipment shown in Figures 18(A) to 18(G) will be explained below.

[0464] Figure 18(A) is a perspective view showing a personal digital information terminal (PDI) 9171. The PDI 9171 can be used, for example, as a smartphone. The PDI 9171 may also be equipped with a speaker 9003, a connection terminal 9006, or a sensor 9007. Furthermore, the PDI 9171 can display text and image information on multiple surfaces. Figure 18(A) shows an example where three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the subject of an email or SNS message, the sender's name, date and time, battery level, signal strength, etc. Alternatively, icons 9050, etc., may be displayed in the position where the information 9051 is displayed.

[0465] Figure 18(B) is a perspective view showing the personal digital assistant (PDA) 9172. The PDA 9172 has the function of displaying information on three or more sides of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, a user can check information 9053, which is displayed in a position that can be observed from above the PDA 9172, while the PDA 9172 is stored in the breast pocket of their clothing. The user can check the display without taking the PDA 9172 out of their pocket and decide, for example, whether or not to answer a call.

[0466] Figure 18(C) is a perspective view showing the tablet terminal 9173. The tablet terminal 9173 can run various applications, such as mobile phone calls, email, document viewing and creation, music playback, internet communication, and computer games. The tablet terminal 9173 has a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the housing 9000, an operation key 9005 as an operation button on the left side of the housing 9000, and a connection terminal 9006 on the bottom.

[0467] Figure 18(D) is a perspective view showing a wristwatch-type personal information terminal 9200. The personal information terminal 9200 can be used, for example, as a smartwatch (registered trademark). The display unit 9001 has a curved display surface, allowing it to display information along the curved surface. The personal information terminal 9200 can also make hands-free calls by communicating with, for example, a wireless communication headset. Furthermore, the personal information terminal 9200 can transmit data to other information terminals and be charged via the connection terminal 9006. Charging may be performed by wireless power supply.

[0468] Figures 18(E) to 18(G) are perspective views showing a foldable portable information terminal 9201. Figure 18(E) shows the portable information terminal 9201 in an unfolded state, Figure 18(G) shows it in a folded state, and Figure 18(F) shows a state in between, transitioning from one of Figures 18(E) or 18(G) to the other. The portable information terminal 9201 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state. The display unit 9001 of the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display unit 9001 can be bent with a radius of curvature of 0.1 mm to 150 mm.

[0469] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, these configuration examples can be appropriately combined. [Examples]

[0470] In this embodiment, we fabricated light-emitting device 1A, which is a light-emitting device according to one aspect of the present invention, and comparative light-emitting devices 1B, 1C, and 1D, and describe the results of measuring the characteristics of each device. A fluorescent light-emitting material was used for the light-emitting layer.

[0471] The structural formulas of the organic compounds used in light-emitting devices 1A to 1D are shown below.

[0472] [ka]

[0473] [ka]

[0474] As shown in Figure 19, each light-emitting device has a sequential stacking structure in which a hole injection layer 911, a hole transport layer 912 (second hole transport layer 912_2 and first hole transport layer 912_1), a light-emitting layer 913, an electron transport layer 914 (first electron transport layer 914_1 and second electron transport layer 914_2), and an electron injection layer 915 are sequentially stacked on a first electrode 901 formed on a glass substrate 900, and a second electrode 902 is stacked on the electron injection layer 915.

[0475] <Method for fabricating light-emitting device 1A> A first electrode 901 was formed on a glass substrate 900 by sputtering a film of indium tin oxide (ITSO) containing silicon oxide to a thickness of 110 nm. The electrode area was 4 mm². 2 (2mm x 2mm)

[0476] Next, as a pretreatment for forming the light-emitting device on the substrate, the substrate surface was washed with water and fired at 200°C for 1 hour. After that, 1 × 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa, and vacuum firing was performed at 170°C for 30 minutes in the heating chamber within the vacuum deposition apparatus. After that, it was allowed to cool naturally.

[0477] Next, the substrate on which the first electrode 901 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 901 is formed faces downwards. Then, N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF) and an electron acceptor material (OCHD-003) containing fluorine with a molecular weight of 672 are co-deposited on the first electrode 901 in a weight ratio of 1:0.03 (=PCBBiF:OCHD-003) and with a film thickness of 10 nm to form a hole injection layer 911.

[0478] Next, a second hole transport layer 912_2 was formed on the hole injection layer 911 by depositing PCBBiF to a thickness of 90 nm. Then, a first hole transport layer 912_1 was formed by depositing N,N-bis{4-[(dibenzofuran-1,2,3,6,7,8,9-d7)-4-yl]phenyl-2,3,5,6-d4}-p-terphenyl-2,2',2'',3,3',3'',4'',5,5',5'',6,6',6''-d13-4-amine (abbreviated as DBfBB1TP-d35) to a thickness of 10 nm.

[0479] Next, on the first hole transport layer 912_1, 1-[10-(phenyl-2,3,4,5,6-d5)-9-anthryl]benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA-02-d5), 9-(1-naphthyl)-10-(2-naphthyl)anthracene-1,2,3,4,5,6,7,8-d8 (abbreviation: α,β-ADN-d8), and N,N'-diphenyl-N,N'-bis(9- A light-emitting layer 913 was formed by co-depositing phenyl-9H-carbazole-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02) in a weight ratio of 0.5:0.5:0.015 (=Bnf(II)PhA-02-d5:α,β-ADN-d8:3,10PCA2Nbf(IV)-02) and a film thickness of 25 nm.

[0480] Next, a first electron transport layer 914_1 was formed on the light-emitting layer 913 by depositing 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as 2mPCCzPDBq) to a thickness of 10 nm. Subsequently, a second electron transport layer 914_2 was formed by depositing 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as mPPhen2P) to a thickness of 15 nm.

[0481] Next, lithium fluoride (LiF) was deposited onto the second electron transport layer 914_2 to a thickness of 1 nm to form an electron injection layer 915.

[0482] Next, a second electrode 902 was formed by depositing aluminum (Al) onto the electron injection layer 915 to a thickness of 150 nm, thereby fabricating the light-emitting device 1A.

[0483] <Method for fabricating light-emitting device 1B> Light-emitting device 1B differs from light-emitting device 1A in the configuration of its light-emitting layer 913. Specifically, in light-emitting device 1A, Bnf(II)PhA-02-d5 used as the first host in the light-emitting layer 913 was replaced with 1-(10-phenyl-9-antryl)benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA-02), and α,β-ADN-d8 used as the second host in the light-emitting layer 913 was replaced with 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviated as α,β-ADN). The other components were fabricated in the same manner as light-emitting device 1A.

[0484] <Method for fabricating light-emitting device 1C> Light-emitting device 1C differs from light-emitting device 1A in the configuration of the first hole transport layer 912_1. Specifically, in light-emitting device 1A, DBfBB1TP-d35 used in the first hole transport layer 912_1 was replaced with N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP). The other components were fabricated in the same manner as light-emitting device 1A.

[0485] <Method for fabricating light-emitting device 1D> Light-emitting device 1D differs from light-emitting device 1C in the configuration of its light-emitting layer 913. Specifically, in light-emitting device 1C, Bnf(II)PhA-02-d5 used as the first host in the light-emitting layer 913 was replaced with Bnf(II)PhA-02, and α,β-ADN-d8 used as the second host in the light-emitting layer 913 was replaced with α,β-ADN. The other components were fabricated in the same manner as light-emitting device 1C.

[0486] The light-emitting device structures of light-emitting devices 1A to 1D are summarized in Table 3 below. Condition 1X is shown in Appendix Table 4.

[0487] [Table 3]

[0488] [Table 4]

[0489] The GSP_slope of Bnf(II)PhA-02-d5 used in light-emitting devices 1A and 1C was 35.2 mV / nm, while the GSP_slope of DBfBB1TP used in light-emitting devices 1C and 1D was 13.3 mV / nm. The GSP_slope of Bnf(II)PhA-02-d5 was greater than that of DBfBB1TP.

[0490] <Light-emitting device characteristics> The above-mentioned light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere to prevent exposure to the atmosphere (sealing material was applied around the element, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour). After this, the characteristics of the light-emitting device were measured.

[0491] Figure 20 shows the luminance-current density characteristics of each light-emitting device, Figure 21 shows the luminance-voltage characteristics, Figure 22 shows the current efficiency-luminance characteristics, Figure 23 shows the current density-voltage characteristics, Figure 24 shows the power efficiency-luminance characteristics, Figure 25 shows the external quantum efficiency-luminance characteristics, and Figure 26 shows the field emission spectrum.

[0492] Furthermore, the brightness of each light-emitting device is 1000 cd / m². 2Table 5 below shows the main characteristics in the vicinity. A spectroradiometer (Topcon SR-UL1R) was used to measure luminance, CIE chromaticity, and emission spectrum. Power efficiency and external quantum efficiency were calculated using luminance and emission spectrum measured from the front of the substrate's light-emitting surface with a spectroradiometer, assuming a Lambertsian light distribution pattern.

[0493] [Table 5]

[0494] From Figure 26 and the table above, it was revealed that light-emitting devices 1A to 1D are light-emitting devices with good characteristics, exhibiting blue light emission originating from 3,10PCA2Nbf(IV)-02. Furthermore, from Figures 20 to 25 and Table 5 above, it was found that light-emitting devices 1A to 1D operate at low voltage and exhibit high external quantum efficiency.

[0495] From the above results, it was found that the light-emitting device according to one aspect of the present invention is a light-emitting device with high luminous efficiency (power efficiency, external quantum efficiency) and low driving voltage.

[0496] <Reliability test results> Furthermore, reliability tests were conducted on light-emitting devices 1A through 1D. Constant current density (50 [mA / cm²] 2 Figure 27 shows the time variation of the normalized brightness during operation. In Figure 27, the vertical axis represents the brightness (%) normalized with the brightness at the start of device operation set to 100%, and the horizontal axis represents the device operation time (h).

[0497] Figure 27 shows that the LT90(h) values, which represent the elapsed time until the measured brightness decreases to 90% of the initial brightness, were 565 hours for light-emitting device 1A, 416 hours for light-emitting device 1B, 537 hours for light-emitting device 1C, and 367 hours for light-emitting device 1D. Therefore, it was found that light-emitting devices 1A to 1C, which contain organic compounds with deuterium, have better reliability than light-emitting device 1D, which consists of organic materials with only light hydrogen.

[0498] In particular, in light-emitting devices 1A and 1C, which use a deuterated organic compound as the host material of the light-emitting layer, it is thought that the excited state generated by carrier recombination in the host material was stabilized, and degradation was suppressed. Furthermore, by using a heteroaromatic ring compound as the first host and a hydrocarbon compound as the second host, the carrier implantability, transportability, or both were improved, and the carrier balance of the entire light-emitting device was improved. As a result, the effect of suppressing the degradation of the host material of the light-emitting layer was significantly observed, and it can be said that a synergistic effect was obtained by deuterating each of the mixed hosts.

[0499] Furthermore, this synergistic effect is more pronounced in devices with high hole trapping capabilities in the light-emitting layer, such as the device described in this example.

[0500] <HOMO and LUMO of the materials used in the luminescent layer> In this example, the HOMO and LUMO levels of the first host Bnf(II)PhA-02 and Bnf(II)PhA-02-d5, the second host α,β-ADN and α,β-ADN-d8, and the guest 3,10PCA2Nbf(IV)-02 used in the light-emitting layer of the light-emitting device fabricated in this embodiment were calculated based on cyclic voltammetry (CV) measurements. The calculation method is shown below.

[0501] An electrochemical analyzer (manufactured by BAS Corporation, model number: ALS Model 600A or 600C) was used as the measuring device. For the CV measurement, the solution was prepared by dissolving anhydrous dimethylformamide (DMF) (manufactured by Aldrich Corporation, 99.8%, catalog number: 22705-6) as the solvent, dissolving tetra-n-butylammonium perchlorate (n-Bu4NClO4) (manufactured by Tokyo Chemical Industry Co., Ltd., catalog number: T0836) as the supporting electrolyte to a concentration of 100 mmol / L, and then dissolving the target substance to a concentration of 2 mmol / L.

[0502] Furthermore, a platinum electrode (PTE platinum electrode manufactured by BAS Corporation) was used as the working electrode, a platinum electrode (Pt counter electrode for VC-3 (5cm) manufactured by BAS Corporation) was used as the auxiliary electrode, and Ag / Ag was used as the reference electrode. + Electrodes (RE7 non-aqueous solvent reference electrode, manufactured by BAS Corporation) were used. Measurements were performed at room temperature (20°C to 25°C). The scan speed during CV measurement was standardized to 0.1 V / sec, and the oxidation potential Ea [V] and reduction potential Ec [V] relative to the reference electrode were measured. Ea was defined as the midpoint potential of the oxidation-reduction wave, and Ec was defined as the midpoint potential of the reduction-oxidation wave. Here, since the potential energy of the reference electrode used in this measurement relative to the vacuum level is known to be -4.94 [eV], the HOMO level [eV] = -4.94 - Ea and the LUMO level [eV] = -4.94 - Ec can be used to determine the HOMO level and LUMO level, respectively.

[0503] Table 6 below summarizes the calculation results for the HOMO and LUMO levels of Bnf(II)PhA-02, Bnf(II)PhA-02-d5, α,β-ADN, α,β-ADN-d8, and 3,10PCA2Nbf(IV)-02.

[0504] [Table 6]

[0505] As shown in the table above, the light-emitting device of this embodiment has a configuration in which the difference between the HOMO levels of the host material and the guest material in the light-emitting layer is 0.4 eV or more, the HOMO of the guest material is high, and hole traps occur. Therefore, in the light-emitting device of this embodiment, which improves the carrier balance by using both heteroaromatic ring compounds and hydrocarbon compounds as the host of the light-emitting layer, the effect of suppressing device degradation is greatly enhanced.

[0506] Furthermore, it was found that light-emitting devices 1A and 1B, which use a deuterated organic compound in the hole transport layer in contact with the light-emitting layer, exhibit significantly better reliability than light-emitting device 1D, which uses only light hydrogen.

[0507] Furthermore, comparing light-emitting device 1A and light-emitting device 1C, it was found that initial degradation was suppressed when a deuterated organic compound was used in the hole transport layer in contact with the light-emitting layer.

[0508] From the above, it has been found that a light-emitting device according to one aspect of the present invention can be driven at a low voltage and provide a light-emitting device with high luminous efficiency and high reliability.

[0509] The configurations, structures, and methods shown in this embodiment can be used in appropriate combination with the configurations, structures, and methods shown in other embodiments and examples. [Examples]

[0510] In this embodiment, a light-emitting device 2A, which is a light-emitting device according to one aspect of the present invention, and comparative light-emitting devices 2B, 2C, and 2D were fabricated, and the results of measuring the characteristics of each device are described. A fluorescent light-emitting material was used for the light-emitting layer.

[0511] The structural formulas of the organic compounds used in light-emitting devices 2A to 2D are shown below.

[0512] [ka]

[0513] As shown in Figure 19, each light-emitting device has a sequential stacking structure in which a hole injection layer 911, a hole transport layer 912 (second hole transport layer 912_2 and first hole transport layer 912_1), a light-emitting layer 913, an electron transport layer 914 (first electron transport layer 914_1 and second electron transport layer 914_2), and an electron injection layer 915 are sequentially stacked on a first electrode 901 formed on a glass substrate 900, and a second electrode 902 is stacked on the electron injection layer 915.

[0514] <Method for fabricating light-emitting device 2A> A first electrode 901 was formed on a glass substrate 900 by sputtering a film of indium tin oxide (ITSO) containing silicon oxide to a thickness of 110 nm. The electrode area was 4 mm². 2 (2mm x 2mm)

[0515] Next, as a pretreatment for forming the light-emitting device on the substrate, the substrate surface was washed with water and fired at 200°C for 1 hour. After that, 1 × 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa, and vacuum firing was performed at 170°C for 30 minutes in the heating chamber within the vacuum deposition apparatus. After that, it was allowed to cool naturally.

[0516] Next, the substrate on which the first electrode 901 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 901 is formed faces downwards. Then, N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF) and an electron acceptor material (OCHD-003) containing fluorine with a molecular weight of 672 are co-deposited on the first electrode 901 in a weight ratio of 1:0.03 (=PCBBiF:OCHD-003) and with a film thickness of 10 nm to form a hole injection layer 911.

[0517] Next, a second hole transport layer 912_2 was formed by depositing PCBBiF on the hole injection layer 911 to a thickness of 90 nm. Then, a first hole transport layer 912_1 was formed by depositing N,N-bis(4-biphenyl-2,2',3,3',4',5,5',6,6'-d9)-6-(phenyl-2,3,4,5,6-d5)benzo[b]naphtho[1,2-d]furan(1,2,3,4,5,9,10,11-d8)-8-amine (abbreviated as BBABnf-d31) to a thickness of 10 nm.

[0518] Next, on the first hole transport layer 912_1, 1-[10-(phenyl-2,3,4,5,6-d5)-9-anthryl]benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA-02-d5), 9-(1-naphthyl)-10-(2-naphthyl)anthracene-1,2,3,4,5,6,7,8-d8 (abbreviation: α,β-ADN-d8), and N,N'-diphenyl-N,N'-bis(9- A light-emitting layer 913 was formed by co-depositing phenyl-9H-carbazole-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02) in a weight ratio of 0.5:0.5:0.015 (=Bnf(II)PhA-02-d5:α,β-ADN-d8:3,10PCA2Nbf(IV)-02) and a film thickness of 25 nm.

[0519] Next, a first electron transport layer 914_1 was formed on the light-emitting layer 913 by depositing 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as 2mPCCzPDBq) to a thickness of 10 nm. Subsequently, a second electron transport layer 914_2 was formed by depositing 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as mPPhen2P) to a thickness of 15 nm.

[0520] Next, lithium fluoride (LiF) was deposited onto the second electron transport layer 914_2 to a thickness of 1 nm to form an electron injection layer 915.

[0521] Next, a second electrode 902 was formed by depositing aluminum (Al) onto the electron injection layer 915 to a thickness of 150 nm, thereby fabricating the light-emitting device 2A.

[0522] <Method for fabricating light-emitting device 2B> Light-emitting device 2B differs from light-emitting device 2A in the configuration of its light-emitting layer 913. Specifically, in light-emitting device 2A, Bnf(II)PhA-02-d5 used as the second host in the light-emitting layer 913 was replaced with 1-(10-phenyl-9-anthryl)benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA-02), and α,β-ADN-d8 was replaced with 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviated as α,β-ADN). The other components were fabricated in the same manner as light-emitting device 2A.

[0523] <Method for fabricating the light-emitting device 2C> Light-emitting device 2C differs from light-emitting device 2A in the configuration of the first hole transport layer 912_1. Specifically, in light-emitting device 2A, BBABnf-d31 used in the first hole transport layer 912_1 was replaced with N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BBABnf). The other components were fabricated in the same manner as light-emitting device 2A.

[0524] <Method for fabricating a 2D light-emitting device> Light-emitting device 2D differs from light-emitting device 2C in the configuration of its light-emitting layer 913. Specifically, in light-emitting device 2C, Bnf(II)PhA-02-d5 used as the first host in the light-emitting layer 913 was replaced with Bnf(II)PhA-02, and α,β-ADN-d8 used as the second host in the light-emitting layer 913 was replaced with α,β-ADN. The other components were fabricated in the same manner as light-emitting device 2C.

[0525] The light-emitting device structures of light-emitting devices 2A to 2D are summarized in Table 7 below. Condition 1X is shown in Appendix Table 8.

[0526] [Table 7]

[0527] [Table 8]

[0528] <Light-emitting device characteristics> The above-mentioned light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere to prevent exposure to the atmosphere (sealing material was applied around the element, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour). After this, the characteristics of the light-emitting device were measured.

[0529] Figure 28 shows the luminance-current density characteristics of each light-emitting device, Figure 29 shows the luminance-voltage characteristics, Figure 30 shows the current efficiency-luminance characteristics, Figure 31 shows the current density-voltage characteristics, Figure 32 shows the power efficiency-luminance characteristics, Figure 33 shows the external quantum efficiency-luminance characteristics, and Figure 34 shows the field emission spectra.

[0530] Furthermore, the brightness of each light-emitting device is 1000 cd / m². 2 Table 9 below shows the main characteristics in the vicinity. A spectroradiometer (Topcon SR-UL1R) was used to measure luminance, CIE chromaticity, and emission spectrum. Power efficiency and external quantum efficiency were calculated using luminance and emission spectrum measured from the front of the substrate's light-emitting surface with a spectroradiometer, assuming a Lambertsian light distribution pattern.

[0531] [Table 9]

[0532] From Figure 34 and Table 9 above, it was revealed that light-emitting devices 2A to 2D are light-emitting devices with good characteristics, exhibiting blue light emission originating from 3,10PCA2Nbf(IV)-02. Furthermore, from Figures 28 to 33 and Table 8 above, it was found that light-emitting devices 2A to 2D can be driven at low voltage.

[0533] From the above results, it was found that the light-emitting device according to one aspect of the present invention is a light-emitting device with a low driving voltage.

[0534] <Reliability test results> Furthermore, reliability tests were conducted on light-emitting devices 2A through 2D. Constant current density (50 [mA / cm²] 2 Figure 35 shows the time variation of the normalized brightness during operation. In Figure 35, the vertical axis represents the normalized brightness (%) with the brightness at the start of device operation set to 100%, and the horizontal axis represents the device operation time (h).

[0535] Figure 35 shows that the LT90(h) values, which represent the elapsed time until the measured brightness decreases to 90% of the initial brightness, were 514 hours for light-emitting device 2A, 336 hours for light-emitting device 2B, 359 hours for light-emitting device 2C, and 274 hours for light-emitting device 2D.

[0536] In particular, in light-emitting devices 2A and 2C, which use a deuterated organic compound as the host material of the light-emitting layer, the excited state generated by carrier recombination in the host material was stabilized, and degradation was suppressed, which is thought to be the reason. Furthermore, by using a heteroaromatic ring compound as the first host and a hydrocarbon compound as the second host, the carrier implantability, transportability, or both were improved, and the carrier balance of the entire light-emitting device was improved. As a result, the effect of suppressing the degradation of the host material of the light-emitting layer was significantly observed, and it can be said that a synergistic effect was obtained by deuterating each of the mixed hosts.

[0537] Furthermore, it was found that light-emitting devices 2A and 2B, which use a deuterated organic compound in the hole transport layer in contact with the light-emitting layer, exhibit significantly better reliability than light-emitting device 2D, which uses only light hydrogen.

[0538] From the above, it has been found that a light-emitting device according to one aspect of the present invention can be driven at a low voltage and provide a light-emitting device with high luminous efficiency and high reliability.

[0539] The configurations, structures, and methods shown in this embodiment can be used in appropriate combination with the configurations, structures, and methods shown in other embodiments and examples. [Explanation of Symbols]

[0540] 100: Display device, 100A: Display device, 100B: Display device, 100C: Display device, 100D: Display device, 100E: Display device, 101: First electrode, 101W: First electrode, 102: Second electrode, 103: Organic compound layer, 103a: Organic compound layer, 103B: Organic compound layer, 103b: Organic compound layer, 103c: Organic compound layer, 103G: Organic compound layer, 103R: Organic compound layer, 104: Common layer, 106: Charge generation layer, 106a: Charge generation layer, 106b: Charge generation layer, 110: Sub-pixel, 110B: Sub-pixel, 110G: Sub-pixel, 110Gw: Width, 1 10R: Sub-pixel, 110Rw: Width, 110W: Sub-pixel, 111: Hole injection layer, 112: Hole transport layer, 112B: Conductive layer, 112R: Conductive layer, 113: Light-emitting layer, 113a: Light-emitting layer, 113b: Light-emitting layer, 113c: Light-emitting layer, 114: Electron transport layer, 115: Electron injection layer, 118: Host material, 118_1: Organic compound, 118_2: Organic compound, 119: Guest material, 120: Substrate, 122: Resin layer, 124a: Pixel, 124b: Pixel, 125: Inorganic insulating layer, 126B: Conductive layer, 126R: Conductive layer, 127: Insulating layer, 128: Layer, 129B: Conductive layer, 129R: Conductive layer, 130: Light-emitting device, 130B: Light-emitting device, 130G: Light-emitting device, 130R: Light-emitting device, 131: Protective layer, 132B: Colored layer, 132G: Colored layer, 132R: Colored layer, 140: Connection part, 141: Region, 142: Adhesive layer, 143: Planarization film, 144: Planarization film, 151: Conductive layer, 151B: Conductive layer, 151C: Conductive layer, 151G: Conductive layer, 151R: Conductive layer, 152: Conductive layer, 152B: Conductive layer, 152C: Conductive layer, 152G: Conductive layer, 152R: Conductive layer, 153: Insulating layer, 155: Common electrode, 156: Insulating layer, 156B: Insulating layer , 156C: insulating layer, 156G: insulating layer, 156R: insulating layer, 157: light shielding layer, 158B: sacrificial layer, 158G: sacrificial layer, 158R: sacrificial layer, 166: conductive layer, 171: insulating layer, 172: conductive layer, 173: insulating layer, 174: insulating layer, 175: insulating layer, 176: plug, 177: pixel part, 178: pixel, 178a: pixel, 178b: pixel, 180: organic resin layer, 181: recess, 181a: recess, 181b: recess, 181c: recess, 182: microlens, 201: transistor, 204: connector part, 205: transistor, 211: insulating layer, 213: insulating layer,214: insulating layer, 215: insulating layer, 221: conductive layer, 222a: conductive layer, 222b: conductive layer, 223: conductive layer, 224B: conductive layer, 224C: conductive layer, 224G: conductive layer, 224R: conductive layer, 231: semiconductor layer, 240: capacitance, 241: conductive layer, 242: connection layer, 243: insulating layer, 245: conductive layer, 254: insulating layer, 255: insulating layer, 256: plug, 261: insulating layer, 271: plug, 280: display module, 281: display unit, 282: circuit unit, 283: pixel circuit unit, 283a: pixel circuit, 284: pixel unit, 284a: pixel, 285: terminal unit, 28 6: Wiring section, 290: FPC, 291: Substrate, 292: Substrate, 301: Substrate, 310: Transistor, 311: Conductive layer, 312: Low resistance region, 313: Insulating layer, 314: Insulating layer, 315: Element isolation layer, 317: Light shielding layer, 351: Substrate, 352: Substrate, 353: FPC, 354: IC, 355: Wiring, 356: Circuit, 700A: Electronic equipment, 700B: Electronic equipment, 721: Housing, 723: Mounting section, 727: Earphone section, 750: Earphone, 751: Display panel, 753: Optical component, 756: Display area, 757: Frame, 758: Nose pad, 800A: Electric Sub-device, 800B: Electronic equipment, 820: Display unit, 821: Housing, 822: Communication unit, 823: Mounting unit, 824: Control unit, 825: Imaging unit, 827: Earphone unit, 832: Lens, 900: Glass substrate, 901: First electrode, 902: Second electrode, 911: Hole injection layer, 912: Hole transport layer, 912_1: First hole transport layer, 912_2: Second hole transport layer, 913: Light-emitting layer, 914: Electron transport layer, 914_1: First electron transport layer, 914_2: Second electron transport layer, 915: Electron injection layer, 6500: Electronic equipment, 6501: Housing, 6502: Display unit, 650 3: Power button, 6504: Button, 6505: Speaker, 6506: Microphone, 6507: Camera, 6508: Light source, 6510: Protective component, 6511: Display panel, 6512: Optical component, 6513: Touch sensor panel, 6515: FPC, 6516: IC, 6517: Printed circuit board, 6518: Battery, 7000: Display unit, 7100: Television equipment, 7151: Remote control unit, 7171: Enclosure, 7173: Stand, 7200: Notebook personal computer, 7211: Enclosure, 7212: Keyboard, 7213: Pointing device7214: External connection port, 7300: Digital signage, 7301: Enclosure, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 9000: Enclosure, 9001: Display unit, 9002: Camera, 9003: Speaker, 9005: Operation keys, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9171: Portable information terminal, 9172: Portable information terminal, 9173: Tablet terminal, 9200: Portable information terminal, 9201: Portable information terminal,

Claims

1. A layer of organic compound is provided between a pair of electrodes. The organic compound layer has a light-emitting layer and a first layer in contact with the light-emitting layer. The light-emitting layer comprises a first organic compound, a second organic compound, and a fluorescent light-emitting material. The first organic compound and the second organic compound, or one or both, have one or more deuterium atoms. The first layer has a third organic compound, The third organic compound is a light-emitting device having one or more deuterium atoms.

2. A layer of organic compound is provided between the pair of electrodes. The organic compound layer has a light-emitting layer and a first layer in contact with the light-emitting layer. The light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance. The second organic compound is an aromatic compound consisting of aromatic hydrocarbons, The first organic compound and the second organic compound, or one or both, have one or more deuterium atoms. The first layer has a third organic compound, The third organic compound is a light-emitting device having one or more deuterium atoms.

3. A layer of organic compound is provided between the pair of electrodes. The organic compound layer has a light-emitting layer and a first layer in contact with the light-emitting layer. The light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance. The first organic compound is an organic compound having a heteroaromatic ring, The first organic compound and the second organic compound, or one or both, have one or more deuterium atoms. The first layer has a third organic compound, The third organic compound is a compound having an aromatic amine skeleton, The third organic compound is a light-emitting device having one or more deuterium atoms.

4. In claim 2 or claim 3, The aforementioned light-emitting material is a fluorescent light-emitting material in the light-emitting device.

5. In any one of claims 1 to 3, The first organic compound and the second organic compound are light-emitting devices having one or more deuterium atoms.

6. In any one of claims 1 to 3, A light-emitting device in which either the first organic compound or the second organic compound has an anthracene skeleton in its molecular structure.

7. In any one of claims 1 to 3, The first and second organic compounds are light-emitting devices having an anthracene skeleton in their molecular structure.

8. In any one of claims 1 to 3, The third organic compound is an aromatic amine compound having a heteroaromatic ring, which is used in this light-emitting device.

9. A layer of organic compound is provided between the pair of electrodes. The organic compound layer has a light-emitting layer and a first layer in contact with the light-emitting layer. The light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance. The first organic compound is an organic compound having a heteroaromatic ring containing anthracene, The second organic compound is an organic compound having a heteroaromatic ring containing anthracene, The first organic compound and the second organic compound have different molecular structures. The first organic compound and the second organic compound, or one or both, have one or more deuterium atoms. The first layer has a third organic compound, The third organic compound is a light-emitting device having one or more deuterium atoms.

10. A layer of organic compound is provided between the pair of electrodes. The organic compound layer has a light-emitting layer and a first layer in contact with the light-emitting layer. The light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance. The first organic compound is an aromatic compound consisting of an aromatic hydrocarbon having anthracene, The second organic compound is an aromatic compound consisting of an aromatic hydrocarbon having anthracene, The first organic compound and the second organic compound have different molecular structures. The first organic compound and the second organic compound, or one or both, have one or more deuterium atoms. The first layer has a third organic compound, The third organic compound is a light-emitting device having one or more deuterium atoms.

11. A layer of organic compound is provided between the pair of electrodes. The organic compound layer has a light-emitting layer and a first layer in contact with the light-emitting layer. The light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance. The first organic compound is represented by the following general formula (G1), The second organic compound is represented by the following general formula (G2): The first organic compound and the second organic compound, or one or both, have one or more deuterium atoms. The first layer has a third organic compound, The third organic compound is a light-emitting device having one or more deuterium atoms. 【Chemistry 1】 (In the formula, R １ ~R ８ Each independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 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, a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, or a cyano group, Ar １ and Ar ２ Each of these independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 1 to 30 carbon atoms, and Ar ３ and Ar ４ Each of these independently represents 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, Ar ３ and Ar ４ One of these is a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. n and m each independently represent an integer from 0 to 4. 【Chemistry 2】 (wherein, R １１ to R １８ each independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a cyano group, Ar １１ and Ar １２ each independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, Ar １３ and Ar １４ each independently represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. p and q each independently represent an integer of 0 to 4.)

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