Light-emitting device

Abstract

To provide a light-emitting device with high luminous efficiency.SOLUTION: A light-emitting device includes a light-emitting layer between a pair of electrodes. The light-emitting layer includes a first compound, a material having a function of converting triplet excited energy into light emission, and a material having a function of converting singlet excited energy into light emission. At least one of the first compound and the material having a function of converting triplet excited energy into light emission includes deuterium. Light emission is obtained from the material having a function of converting singlet excited energy into light emission.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] One aspect of the present invention relates to an organic compound, an organic semiconductor device, a light-emitting device, a photodiode sensor, a display module, a lighting module, a display device, an electronic device, a lighting device, and an electronic device. Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification or the like relates to an object, a method, or a manufacturing method. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one aspect of the present invention disclosed in this specification include a semiconductor device, a display device, a liquid crystal display device, a lighting device, a power storage device, a storage device, an imaging device, a driving method thereof, or a manufacturing method thereof.

Background Art

[0002] The practical application of light-emitting devices (also referred to as organic EL elements) that utilize electroluminescence (EL) using organic compounds has been progressing. The basic configuration of these light-emitting devices is such that an organic compound layer (also referred to as an EL layer) containing a light-emitting material is sandwiched between a pair of electrodes. By applying a voltage to this device to inject carriers and utilizing the recombination energy of the carriers, light emission from the light-emitting material can be obtained.

[0003] Since the light-emitting device is a self-luminous type, a display device using the light-emitting device as a pixel has higher visibility than a liquid crystal display device and does not require a backlight. In addition, a display device using such a light-emitting device can be manufactured to be thin and lightweight, which is also a great advantage. Furthermore, it is also characterized by a very fast response speed.

[0004] In addition, since these light-emitting devices can form a light-emitting layer continuously in a planar shape, planar light emission can be obtained. This is a characteristic that is difficult to achieve with point light sources typified by incandescent bulbs and LEDs, or line light sources typified by fluorescent lamps. Therefore, it has high utility value as a surface light source that can be applied to lighting and the like.

[0005] As described above, display devices and lighting devices using such light-emitting devices are suitable for various electronic devices, and research and development are being advanced to obtain light-emitting devices having better characteristics.

[0006] Patent Document 1 discloses a light-emitting device in which a metal complex is paired with a deuterated host, and the reliability is improved by delaying the decomposition mechanism that deteriorates the metal complex.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of one aspect of the present invention is to provide a light-emitting device having good characteristics. Or, an object of one aspect of the present invention is to provide a light-emitting device having good reliability. Or, an object of one aspect of the present invention is to provide a light-emitting device having a low driving voltage. Or, an object of one aspect of the present invention is to provide a light-emitting device having good reliability and a low driving voltage.

[0009] Alternatively, in one aspect of the present invention, an object is to provide a light-emitting device capable of providing a display device with good characteristics. Alternatively, in one aspect of the present invention, an object is to provide a light-emitting device capable of providing a display device with good reliability. Alternatively, in one aspect of the present invention, an object is to provide a light-emitting device capable of providing a display device with a low driving voltage. Alternatively, in one aspect of the present invention, an object is to provide a light-emitting device capable of providing a display device with a low driving voltage and good reliability.

[0010] Alternatively, an object is to provide any one of an organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device with low power consumption. Alternatively, an object is to provide either a highly reliable electronic device or a lighting device.

[0011] The present invention only needs to solve any one of the above-described problems.

Means for Solving the Problems

[0012] One aspect of the present invention is a light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a first compound, a material having a function of converting triplet excitation energy into light emission, and a material having a function of converting singlet excitation energy into light emission, and at least one of the first compound and the material having a function of converting triplet excitation energy into light emission has deuterium, and light emission is obtained from the material having a function of converting singlet excitation energy into light emission.

[0013] One aspect of the present invention is a light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer has a first compound, a second compound, a material having a function of converting triplet excitation energy into light emission, and a material having a function of converting singlet excitation energy into light emission, and at least one of the first compound, the second compound, and the material having a function of converting triplet excitation energy into light emission has deuterium, and light emission is obtained from the material having a function of converting singlet excitation energy into light emission.

[0014] In the above, the first compound has a π-electron-deficient heteroaromatic ring, and the second compound has at least one of a π-electron-excessive heteroaromatic ring and an aromatic amine skeleton.

[0015] In the above, the difference between the lowest triplet excitation energy level (T1 level) of the first compound and the lowest triplet excitation energy level of the second compound is 0.20 eV or less.

[0016] In the above, the first compound and the second compound are a combination that forms an exciplex, and the emission spectrum of the exciplex overlaps with the emission spectrum of the material having a function of converting triplet excitation energy into light emission.

[0017] In any of the above inventions, the first compound has deuterium, and the phosphorescence emission lifetime or delayed fluorescence lifetime of the first compound at 77K is longer than the phosphorescence emission lifetime or delayed fluorescence lifetime of the non-deuterated form of the first compound at 77K.

[0018] In any of the above inventions, the second compound has deuterium, and the phosphorescence emission lifetime or delayed fluorescence lifetime of the second compound at 77K is longer than the phosphorescence emission lifetime or delayed fluorescence lifetime of the non-deuterated form of the second compound at 77K.

[0019] In any of the above inventions, a material having a function of converting triplet excitation energy into light emission has deuterium, and the phosphorescence emission lifetime or delayed fluorescence lifetime at room temperature of the material having a function of converting triplet excitation energy into light emission is longer than the phosphorescence emission lifetime or delayed fluorescence lifetime at room temperature of the non-deuterated form of the material having a function of converting triplet excitation energy into light emission. This is a light-emitting device.

[0020] In any of the above inventions, a material having a function of converting triplet excitation energy into light emission is a light-emitting device that is a phosphorescent material.

[0021] In any of the above inventions, a material having a function of converting triplet excitation energy into light emission is a light-emitting device that is a TADF material.

[0022] In any of the above inventions, a material having a function of converting singlet excitation energy into light emission is a light-emitting device that is a fluorescent material.

[0023] In any of the above inventions, a material having a function of converting singlet excitation energy into light emission is a fluorescent material having a light-emitting group and a protecting group. The light-emitting group is a condensed aromatic ring or a condensed heteroaromatic ring, and the protecting group has any one of an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a trialkylsilyl group having 3 to 10 carbon atoms. This is a light-emitting device. Also, the protecting group has deuterium. This is a light-emitting device.

[0024] In any of the above inventions, a material having a function of converting singlet excitation energy into light emission is a light-emitting device that is a TADF material.

[0025] Alternatively, another aspect of the present invention is a display device including the light-emitting device described in any of the above.

[0026] Alternatively, another aspect of the present invention is an electronic device having the above light-emitting device, a sensor, an operation button, a speaker, or a microphone.

[0027] Alternatively, another aspect of the present invention is a lighting device including the above light-emitting device and a housing.

Advantages of the Invention

[0028] In one aspect of the present invention, a light-emitting device with high luminous efficiency can be provided. Alternatively, in one aspect of the present invention, a light-emitting device with good reliability can be provided. Alternatively, any one of a display device, an electronic device, and a lighting device with low power consumption can be provided. Alternatively, any one of a display device, an electronic device, and a lighting device with high reliability can be provided.

[0029] Note that the description of these effects does not prevent the existence of other effects. Note that one aspect of the present invention does not necessarily have all of these effects. Note that other effects will be naturally apparent from the description in the specification, drawings, claims, etc., and it is possible to extract these other effects from the description in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0030]

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DETAILED DESCRIPTION OF THE INVENTION

[0031] (Embodiment 1) In this embodiment, a light-emitting device according to one aspect of the present invention will be described.

[0032] 〔Configuration Example of Light-Emitting Device〕 First, the configuration of a light-emitting device according to one aspect of the present invention will be described with reference to FIGS. 1(A) to 1(C).

[0033] FIG. 1(A) is a schematic cross-sectional view of a light-emitting device 10 according to one aspect of the present invention.

[0034] 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. The organic compound layer 103 is also referred to as an EL layer.

[0035] In addition, the organic compound layer 103 shown in FIG. 1(A) has 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.

[0036] In addition, in the present embodiment, among the pair of electrodes, the first electrode 101 is described as the anode and the second electrode 102 is described as the cathode. However, the configuration of the light-emitting device 10 is not limited to this. That is, the first electrode 101 may be the cathode, the second electrode 102 may be the anode, and the lamination of each layer between the electrodes may be in the reverse order. That is, from the anode side, 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 may be laminated in this order.

[0037] Note that the configuration of the organic compound layer 103 is not limited to the configuration shown in FIG. 1(A), and may be a configuration having at least one selected from the hole injection layer 111, the hole transport layer 112, the electron transport layer 114, and the electron injection layer 115. Alternatively, the organic compound layer 103 may be a configuration having a functional layer having functions such as reducing the injection barrier of holes or electrons, improving the transportability of holes or electrons, inhibiting the transportability of holes or electrons, or suppressing the quenching phenomenon by the electrode. Note that each functional layer may be a single layer or a configuration in which a plurality of layers are laminated.

[0038] FIGS. 1(B) and 1(C) are cross-sectional schematic views showing an example of the light-emitting layer 113 shown in FIG. 1(A). The light-emitting layer 113 shown in FIG. 1(B) has compound 131, compound 132, compound 133, and compound 134. The light-emitting layer 113 shown in FIG. 1(C) has compound 131, compound 133, and compound 134. Note that compound 131 and compound 132 are substances that each function as a host material. Compound 133 is a material having a function of converting triplet excitation energy into light emission. Compound 134 is a material having a function of converting singlet excitation energy into light emission. In addition, the light-emitting layer 113 can obtain light emission derived from compound 134, which is a material having a function of converting singlet excitation energy into light emission.

[0039] <Example Configuration 1 of Light-Emitting Layer> First, a specific configuration example 1 of the light-emitting layer 113 will be described. In this configuration example, as shown in FIG. 1(B), the light-emitting layer 113 includes compound 131, compound 132, compound 133, and compound 134. Also, in this configuration example, a case will be described where compound 133, which is a material having a function of converting triplet excitation energy into light emission, is a phosphorescent material, and compound 134, which is a material having a function of converting singlet excitation energy into light emission, is a fluorescent material. An example of the energy level correlation in the light-emitting layer 113 in this configuration example is as shown in FIG. 2(A). Note that the notations and symbols in FIG. 2(A) are as follows. ·Comp(131): Compound 131 ·Comp(132): Compound 132 ·Comp(133): Compound 133 ·Guest(134): Compound 134 ·S C1 : S1 level of compound 131 ·T C1 : T1 level of compound 131 ·S C2 : S1 level of compound 132 ·T C2 : T1 level of compound 132 ·S E : S1 level of the exciplex ·T E : T1 level of the exciplex ·T C3 : T1 level of compound 133 ·S G : S1 level of compound 134 ·T G : T1 level of compound 134

[0040] The combination of Compound 131 and Compound 132, each of which functions as a host material, is preferably a combination capable of forming an exciplex, and it is more preferable that one is a hole-transporting material and the other is an electron-transporting material. In this case, it becomes easier to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of Compound 131 and Compound 132 is a combination of a compound having hole-transporting properties and a compound having electron-transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of the compound having hole-transporting properties: the compound having electron-transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Also, by having this configuration, since the carrier balance can be easily controlled, the control of the carrier recombination region can also be easily performed.

[0041] More specifically, examples of the hole-transporting material include compounds having either one or both of a π-electron excess type heteroaromatic ring and an aromatic amine skeleton, and more specifically, examples of the electron-transporting material include compounds having a π-electron deficient type heteroaromatic ring.

[0042] Further, as a combination of host materials that efficiently form an exciplex, it is preferable that the HOMO level of one of Compound 131 and Compound 132 is higher than the HOMO level of the other, and the LUMO level of one is higher than the LUMO level of the other. Note that the HOMO level of Compound 131 may be equivalent to the HOMO level of Compound 132, or the LUMO level of Compound 131 may be equivalent to the LUMO level of Compound 132.

[0043] Note that the LUMO level and HOMO level of a compound can be derived from the electrochemical properties (reduction potential and oxidation potential) of the compound measured by cyclic voltammetry (CV) measurement or the like.

[0044] As shown in FIG. 2(A), the S1 level (S E ) of the exciplex formed by Compound 131 and Compound 132 and the T1 level (T E) become adjacent energy levels (see Route A1 in Fig. 2(A)).

[0045] The excited energy levels (S E and T E ) of the exciplex formed by Compound 131 and Compound 132 are lower than the S1 levels (S C1 and S C2 ) of each substance (Compound 131 and Compound 132) forming the exciplex. Therefore, it is possible to form an excited state with a lower excitation energy. As a result, the driving voltage of the light-emitting device can be reduced. The formation of the exciplex can be confirmed, for example, by comparing the emission spectra of Compound 131, the emission spectrum of Compound 132, and the emission spectrum of a mixed film of Compound 131 and Compound 132, and observing the phenomenon that the emission spectrum of the mixed film is shifted to a longer wavelength (or has a new peak on the longer wavelength side) than the emission spectra of the respective materials.

[0046] Note that the correlation of the energy levels between Compound 131 and Compound 132 is not limited to Fig. 2(A). That is, the singlet excited energy level (S C1 ) of Compound 131 may be higher or lower than the singlet excited energy level (S C2 ) of Compound 132. Also, the triplet excited energy level (T C1 ) of Compound 131 may be higher or lower than the triplet excited energy level (T C2 ) of Compound 132.

[0047] Since Compound 133 is a phosphorescent substance, both singlet and triplet excitation energies quickly move from the S1 level (S E ) and the T1 level (T E ) of the exciplex formed by Compound 131 and Compound 132 to the T1 level (T C3 ) of Compound 133 (Route A2). At this time, T E ≥ T C3is preferable. In Route A2, the exciplex functions as an energy donor, and Compound 133 functions as an energy acceptor.

[0048] In addition, the triplet excitation energy of Compound 133 is converted into the singlet excitation energy of Compound 134, which is a fluorescent substance (Route A3). At this time, as shown in FIG. 2(A), when T E ≧T C3 ≧S G it is preferable because the energy transfer from Compound 133 to Compound 134 occurs efficiently. More specifically, a tangent is drawn at the short-wavelength side skirt of the phosphorescence spectrum of Compound 133, and the energy of the wavelength of the extrapolated line is defined as T C3 and the energy of the wavelength at the absorption edge of the absorption spectrum of Compound 134 is defined as S G when T C3 ≧S G is preferable. In Route A3, Compound 133 functions as an energy donor, and Compound 134 functions as an energy acceptor.

[0049] However, in the light-emitting layer 113 of the light-emitting device shown in this configuration example, in addition to the above, a path (Route A4 in FIG. 2(A)) may occur in which the triplet excitation energy of Compound 133 moves to the T1 level of Compound 134. When such energy transfer (Route A4) occurs, Compound 134, which is a fluorescent substance, cannot contribute the triplet excitation energy to light emission, so the light-emitting efficiency of the light-emitting device decreases.

[0050] Generally, as intermolecular energy transfer mechanisms, the Förster mechanism (dipole-dipole interaction) and the Dexter mechanism (electron exchange interaction) are known. Also, the Dexter mechanism predominantly occurs when the distance between the compound that is the energy donor and the compound that is the energy acceptor is 1 nm or less. Therefore, as the concentration of the compound that is the energy acceptor increases, the Dexter mechanism is more likely to occur. Thus, as in this configuration example, when compound 134, which is the energy acceptor, is a fluorescent material with a low triplet excitation energy level and its concentration increases, the triplet excitation energy of compound 133, which is the energy donor, is predominantly governed by energy transfer via route A4 due to the Dexter mechanism and subsequent non-radiative deactivation. Therefore, in order to suppress route A4, it is more preferable to increase the distance between compound 133 and compound 134 to such an extent that energy transfer due to the Dexter mechanism is less likely to occur.

[0051] Also, the T1 level (T G ) of compound 134, which is the energy acceptor, is often an energy level derived from the emitting group that compound 134 has. Therefore, in order to suppress route A4 in the light-emitting layer 113, it is more preferable to increase the distance between compound 133 and the emitting group that compound 134 has.

[0052] Generally, as a method for increasing the distance between the energy donor and the emitting group that the energy acceptor has, reducing the concentration of the energy acceptor in the mixed film is mentioned. However, when the concentration of the energy acceptor is reduced, not only the energy transfer based on the Dexter mechanism from the energy donor to the energy acceptor but also the energy transfer based on the Förster mechanism is suppressed. In that case, since route A3 is based on the Förster mechanism, problems such as a decrease in the luminous efficiency or reliability of the light-emitting device occur.

[0053] Therefore, it is preferable that the compound 134, which is an energy acceptor, is a compound having a light-emitting group as part of its structure and a protecting group having a function of increasing the distance between the light-emitting group and another energy donor. Note that when the distance between the energy donor and the energy acceptor is 1 nm or less, the Dexter mechanism is dominant, and when it is 1 nm or more and 10 nm or less, the Förster mechanism is dominant. Therefore, the protecting group is preferably a bulky substituent that extends in the range of 1 nm or more and 10 nm or less from the light-emitting group. By using such a compound as the compound 134, even when the concentration of the compound 134 is increased, the energy transfer by the Dexter mechanism can be suppressed while increasing the energy transfer rate by the Förster mechanism. That is, the energy transfer (route A3) of the triplet excitation energy from the compound 133 to the S1 level (S G ) of the compound 134 is likely to occur, while the transfer of the triplet excitation energy from the compound 133 to the T1 level (T G ) of the compound 134 (route A4: energy transfer by the Dexter mechanism) can be made less likely to occur, and the decrease in the luminous efficiency associated with the energy transfer of route A4 can be suppressed while increasing the luminous efficiency of the light-emitting device.

[0054] Also, in this configuration example, by increasing the concentration of the compound 134, which is an energy acceptor, the energy transfer by the Dexter mechanism can be suppressed while increasing the energy transfer rate by the Förster mechanism. Note that by increasing the energy transfer rate by the Förster mechanism, the excitation lifetime of the energy acceptor in the light-emitting layer is shortened, so that the reliability of the light-emitting device can be improved. Specifically, the concentration of the compound 134 in the light-emitting layer 113 is preferably 2 wt% or more and 50 wt% or less, more preferably 5 wt% or more and 30 wt% or less, and still more preferably 5 wt% or more and 20 wt% or less, relative to the compound 133, which is an energy donor.

[0055] In the present specification, the paths of Route A1 and Route A2 described above are also referred to as ExTET (Exciplex-Triplet Energy Transfer). That is, in the light-emitting layer 113 in the present specification, it indicates that there is donation of excitation energy from an exciplex to Compound 133.

[0056] <Example Configuration 2 of Light-Emitting Layer> Next, a specific example configuration 2 of the light-emitting layer 113 will be described. In this example configuration, the light-emitting layer 113 has Compound 131, Compound 132, Compound 133, and Compound 134 as shown in Fig. 1(B). Also, in this example configuration, the case where Compound 133, which is a material having a function of converting triplet excitation energy into light emission, is a phosphorescent material and Compound 134, which is a material having a function of converting singlet excitation energy into light emission, is a thermally activated delayed fluorescence (TADF) material will be described. Note that the TADF material is a material having a function of converting both singlet excitation energy and triplet excitation energy into light emission. An example of the energy level correlation in the light-emitting layer 113 in this example configuration is as shown in Fig. 2(B). Note that the notations, reference signs, Route A1, and Route A2 in Fig. 2(B) are the same as those in Fig. 2(A), so the description thereof is omitted.

[0057] The triplet excitation energy that has moved from the exciplex formed by Compound 131 and Compound 132 to Compound 133 by Route A2 shown in Fig. 2(B) is converted into the singlet excitation energy of Compound 134, which is a TADF material (Route A5). At this time, as shown in Fig. 2(B), when E ≧T C3 ≧S G it is the case, the energy transfer from Compound 133 to Compound 134 is preferably performed efficiently. More specifically, a tangent is drawn at the short-wavelength side skirt of the phosphorescence spectrum of Compound 133, and the energy of the wavelength of the extrapolated line is defined as T C3 and the energy of the wavelength at the absorption edge of the absorption spectrum of Compound 134 is defined as S G when, T C3 ≧SG is preferably.

[0058] In addition, in the light-emitting layer 113 of the light-emitting device shown in this configuration example, in addition to the above, the triplet excitation energy of compound 133 moves to the T1 level of compound 134 (route A6 in Fig. 2(B)). In this configuration example, since compound 134 is a TADF material, it has a function of converting triplet excitation energy into singlet excitation energy by upconversion. Therefore, the triplet excitation energy converted by route A6 is converted into singlet excitation energy by upconversion (route A7 in Fig. 2(B)) and exhibits thermally activated delayed fluorescence. Thus, compound 134 can efficiently exhibit light emission from the singlet excited state and can increase the light emission efficiency of the light-emitting device. In routes A5 and A6, compound 133 functions as an energy donor and compound 134 functions as an energy acceptor.

[0059] In Configuration Example 1 and Configuration Example 2, the configuration in which the light-emitting layer 113 has four compounds (compound 131, compound 132, compound 133, and compound 134) was shown, but one aspect of the present invention is not limited to this. In the following Configuration Example 3 and Configuration Example 4, a configuration in which the light-emitting layer 113 has three compounds (compound 131, compound 133, and compound 134) will be described.

[0060] 〈Configuration Example 3 of Light-Emitting Layer〉 A specific Configuration Example 3 of the light-emitting layer 113 will be described. In this configuration example, as shown in Fig. 1(C), the light-emitting layer 113 has compound 131, compound 133, and compound 134. Also, in this configuration example, a case will be described where compound 133, which is a material having a function of converting triplet excitation energy into light emission, is a phosphorescent material, and compound 134, which is a material having a function of converting singlet excitation energy into light emission, is a fluorescent material. An example of the energy level correlation in the light-emitting layer 113 in this configuration example is as shown in Fig. 2(C). The notations and symbols in Fig. 2(C) are as follows. ·Comp(131): Compound 131 ·Comp(133): Compound 133 ·Guest(134): Compound 134 ·S C1 : S1 level of Compound 131 ·T C1 : T1 level of Compound 131 ·T C3 : T1 level of Compound 133 ·T G : T1 level of Compound 134 ·S G : S1 level of Compound 134

[0061] In this structural example, recombination of carriers mainly occurs in Compound 131, thereby generating singlet excitons and triplet excitons. Note that as Compound 133, by selecting a phosphorescent material having a relationship of T C3 ≤ T C1 both the singlet excitation energy and the triplet excitation energy generated in Compound 131 can be transferred to the T C3 level of Compound 133 (Route A in Fig. 2(C) 18 ). Note that some carriers may also recombine in Compound 133.

[0062] Note that the phosphorescent material used in the above structure preferably contains heavy atoms such as Ir, Pt, Os, Ru, Pd, etc. When the phosphorescent material is used as Compound 133, energy transfer from the triplet excitation energy level of the energy donor to the singlet excitation energy level of the guest material (energy acceptor) is an allowed transition, which is preferable. Therefore, the triplet excitation energy of Compound 133 can be transferred to the S1 level (S 19 ) of the guest material through the route of Route A G . In Route A 19 , Compound 133 functions as an energy donor and Compound 134 functions as an energy acceptor. In this case, T C3 ≥ S GIf so, it is preferable because the excitation energy of Compound 133 efficiently transfers to the singlet excited state of Compound 134 which is the guest material. Specifically, a tangent is drawn at the trailing edge on the short wavelength side of the phosphorescence spectrum of Compound 133, and the energy of the wavelength of the extrapolated line is defined as T C3 and the energy of the wavelength at the absorption edge of the absorption spectrum of Compound 134 is defined as S G . When this is done, it is preferable that T C3 ≥ S G . However, in the light-emitting layer 113 of the light-emitting device shown in this configuration example, in addition to the above, the triplet excitation energy of Compound 133 can also compete with the path (Route A 20 in FIG. 2(C)) for transferring to the T1 level of Compound 134. When such energy transfer (Route A 20 ) occurs, since Compound 134 which is a fluorescent light-emitting substance cannot contribute the triplet excitation energy to light emission, the light-emitting efficiency of the light-emitting device decreases.

[0063] In order to suppress such energy transfer (Route A 20 ), as described in Configuration Example 1 above, it is important that the distance between Compound 133 and Compound 134, that is, the distance between the light-emitting groups possessed by Compound 133 and Compound 134 is long.

[0064] The compound which is one aspect of the present invention has a light-emitting group and a protecting group in a part of its structure. When functioning as an energy acceptor in the light-emitting layer 113, the protecting group has a function of increasing the distance between another energy donor and the light-emitting group. Therefore, when the compound which is one aspect of the present invention is used as Compound 134 of this configuration, even if the concentration of Compound 134 is increased, the distance between Compound 133 and Compound 134 can be increased, and while suppressing the energy transfer by the Dexter mechanism, the energy transfer rate by the Förster mechanism can be increased. Therefore, by using the compound which is one aspect of the present invention as Compound 134, the energy transfer (Route A G ) of the triplet excitation energy from Compound 133 to the S1 level (S 19 ) of Compound 134 becomes likely to occur, while the triplet excitation energy from Compound 133 to the T1 level (TG ) Triplet excitation energy transfer to (Route A 20 : Energy transfer by Dexter mechanism) can be made less likely to occur, and while suppressing the decrease in luminous efficiency associated with the energy transfer of Route A 20 , the luminous efficiency of the light-emitting device can be increased. Also, the reliability of the light-emitting device can be improved.

[0065] 〈Example 4 of the structure of the light-emitting layer〉 In this exemplary configuration, the light-emitting layer 113 in the light-emitting device has Compound 131, Compound 134, and Compound 133 as shown in Fig. 1(C). Note that Compound 133, which is a material having a function of converting triplet excitation energy into light emission, is a TADF material, and the case where Compound 134, which is a material having a function of converting singlet excitation energy into light emission, is a fluorescent light-emitting substance is shown. Note that an example of the correlation of energy levels in the light-emitting layer 113 in this exemplary configuration is as shown in Fig. 2(D). Note that the notations and symbols in Fig. 2(D) are the same as the notations and symbols shown in Fig. 2(C), and the rest are as follows. ·S C3 : S1 level of Compound 133

[0066] In this exemplary configuration, singlet excitons and triplet excitons are generated mainly by the recombination of carriers in Compound 131. Note that as Compound 133, by selecting a TADF material having the relationship of S C3 ≦S C1 and T C3 ≦T C1 , both the singlet excitation energy and the triplet excitation energy generated in Compound 131 can be transferred to the S C3 and T C3 levels of Compound 133 (Route A in Fig. 2(D) 21 ). Note that some carriers can also recombine in Compound 133.

[0067] Note that since Compound 133 is a TADF material, it has a function of converting triplet excitation energy into singlet excitation energy by upconversion (Route A in Fig. 2(D)22 )。 Also, the singlet excitation energy of compound 133 can quickly transfer to compound 134 (Route A in Fig. 2(D)) 23 ). At this time, it is preferable that S C3 ≥ S G . More specifically, a tangent is drawn at the short-wavelength side skirt of the fluorescence spectrum of compound 133, and the energy of the wavelength of the extrapolated line is defined as S C3 , and when the energy of the wavelength at the absorption edge of the absorption spectrum of compound 134 is defined as S G , it is preferable that S C3 ≥ S G .

[0068] Therefore, in the light-emitting layer 113 of the light-emitting device shown in this configuration example, through the paths of Route A 21 , Route A 22 , and Route A 23 in Fig. 2(D), the triplet excitation energy generated in compound 133 can be converted into fluorescence emission of compound 134. In Route A 23 , compound 133 functions as an energy donor and compound 134 functions as an energy acceptor. However, in the light-emitting layer 113 of the light-emitting device shown in this configuration example, in addition to the above, the triplet excitation energy of compound 133 can also compete with the path (Route A 24 in Fig. 2(D)) that transfers to the T1 level of compound 134. When such energy transfer (Route A 24 ) occurs, the fluorescent substance compound 134 cannot contribute the triplet excitation energy to emission, resulting in a decrease in the emission efficiency of the light-emitting device.

[0069] To suppress such energy transfer (Route A 24 ), as described in Configuration Example 1 above, it is important that the distance between compound 133 and compound 134, that is, the distance between the light-emitting groups of compound 133 and compound 134 is long.

[0070] A compound according to one embodiment of the present invention has a lumophore and a protecting group in a part of its structure. When functioning as an energy acceptor in the light-emitting layer 113, the protecting group has a function of increasing the distance between the other energy donor and the lumophore. Therefore, when the compound according to one embodiment of the present invention is used as the compound 134 in this configuration, even if the concentration of the compound 134 is increased, the distance between the compound 133 and the compound 134 can be increased, suppressing energy transfer by the Dexter mechanism while increasing the energy transfer rate by the Förster mechanism. Therefore, by using the compound according to one embodiment of the present invention as the compound 134, the triplet excitation energy transfer from the compound 133 to the S1 level (S G ) of the compound 134 (Route A 23 ) becomes likely to occur, while the transfer of triplet excitation energy from the compound 133 to the T1 level (T G ) of the compound 134 (Route A 24 : energy transfer by the Dexter mechanism) can be made less likely to occur. Therefore, it is possible to suppress a decrease in luminous efficiency associated with the energy transfer of Route A 24 while increasing the luminous efficiency of the light-emitting device. Also, the reliability of the light-emitting device can be improved.

[0071] In Route A2 of Configuration Example 1 and Configuration Example 2 of the light-emitting layer configuration described above, the exciplex formed by the compound 131 and the compound 132 functions as an energy donor, and in Route A3 of Configuration Example 1 and Routes A5 and A6 of Configuration Example 2, by the compound 133 functioning as an energy donor, a highly efficient light-emitting device can be obtained. Also, in Route A 18 of Configuration Example 3 of the light-emitting layer, the compound 131 functions as an energy donor, and in Route A 19 , by the compound 133 functioning as an energy donor, a highly efficient light-emitting device can be obtained. Also, in Route A 21 of Configuration Example 4 of the light-emitting layer, the compound 131 functions as an energy donor, and in Route A 23 , by the compound 133 functioning as an energy donor, a highly efficient light-emitting device can be obtained.

[0072] Here, at least any one, preferably any two, and most preferably all of Compound 131, Compound 132, and Compound 133, which function as an energy donor in the light-emitting layer, preferably have deuterium. This is because the bond dissociation energy of the bond between carbon and deuterium is greater than that of the bond between carbon and light hydrogen, and it is stable and difficult to break. Therefore, a compound having deuterium is more stable and less likely to deteriorate compared to a non-deuterated compound. By having at least any one, preferably any two, and most preferably all of Compound 131, Compound 132, and Compound 133 have deuterium, the stability of the compound can be enhanced, and the deterioration of the energy donor can be suppressed. Thus, it is possible to suppress the decrease in the energy transfer efficiency to Compound 134 over time, and the reliability of the light-emitting device can be improved.

[0073] In addition, when Compound 131, Compound 132, and Compound 133 are compounds having deuterium, they may each be a compound having both hydrogen and deuterium, or a compound having no hydrogen and only deuterium.

[0074] Further, although the whole molecules of Compound 131 and Compound 132 may be deuterated, it is preferable that the group or skeleton where the lowest triplet excitation energy level is localized is deuterated. Thereby, Compound 131 and Compound 132 can be obtained at a lower cost than deuterating the whole molecules.

[0075] Also, although the whole molecule of Compound 133 may be deuterated, it is preferable that a group that is relatively easily cleaved is deuterated. For example, when an organometallic complex containing an alkyl group such as a methyl group is used for at least one of the ligands in Compound 133, it is preferable that the alkyl group is deuterated. Thereby, Compound 133 can be obtained at a lower cost than deuterating the whole molecule, and the reliability of the light-emitting device can be improved.

[0076] As used herein, "having deuterium" means that the ratio of deuterium in the hydrogen and deuterium of a compound is significantly higher than the natural abundance ratio of deuterium, specifically 500 times or more. "Deuterated compound" means a compound in which the ratio of deuterium in the hydrogen and deuterium of the compound is significantly higher than the natural abundance ratio of deuterium, specifically 500 times or more. Also, this ratio is not the ratio per molecule, but the average of a plurality of target compounds present in a certain area.

[0077] In addition to the above configuration, it is more preferable that Compound 134, which functions as an energy acceptor in the light-emitting layer, has deuterium. As described above, since a compound having deuterium is more stable and less likely to deteriorate compared to its non-deuterated form, the stability of Compound 134 can be enhanced by having deuterium. Therefore, since the decrease in the luminous efficiency of the light-emitting device over time can be suppressed by Compound 134 having deuterium, the reliability of the light-emitting device can be improved.

[0078] The whole molecule of Compound 134 may be deuterated. However, when using a fluorescent substance having deuterium as Compound 134, it is more preferable to use a fluorescent substance in which the protecting group is deuterated. Compound 134 can be obtained at a lower cost than deuterating the whole molecule, and the reliability of the light-emitting device can be improved. In particular, when the protecting group is an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a trialkylsilyl group having 3 to 10 carbon atoms, deterioration starting from the hydrogen of these groups can be suppressed.

[0079] In addition, at least one of Compound 131, Compound 132, and Compound 133, preferably any two of them, and most preferably all of them, which function as an energy donor in the light-emitting layer and have deuterium, can enhance the reliability of the light-emitting device for another reason that the phosphorescence lifetime or delayed fluorescence lifetime of the deuterated compound becomes longer than the phosphorescence lifetime or delayed fluorescence lifetime of the non-deuterated compound, thereby improving the energy transfer efficiency. This is because the intramolecular vibration in the lowest triplet excited state (T1 state) of the deuterated compound is more suppressed than the intramolecular vibration of the non-deuterated compound, and the non-radiative transition from the T1 state to a more stable state is suppressed.

[0080] The energy transfer efficiency φ from the energy donor to the energy acceptor ET is represented by the following formula (1). From this formula, the energy transfer efficiency φ ET To increase, the rate constant k of energy transfer h*→g should be increased, and the other competing rate constants k r + k nr (= 1 / τ) should be relatively small.

[0081] In formula (1), k r represents the rate constant of the light-emitting process of the energy donor (fluorescence when discussing energy transfer from the singlet excited state, phosphorescence or delayed fluorescence when discussing energy transfer from the triplet excited state), k nr represents the rate constant of the non-light-emitting process (thermal deactivation and intersystem crossing) of the energy donor, and τ represents the measured lifetime of the excited state of the energy donor. Also, k h*→g represents the rate constant of energy transfer (Förster mechanism or Dexter mechanism).

[0082]

Number

[0083] The rate constant k of energy transfer h*→gIn a compound that is not a deuterated compound, since the atomic arrangement and spectral shape of the molecule are almost unchanged, they are almost identical (see the following formula (2) or (3)). Therefore, in the comparison with a compound that is not a deuterated compound, the rate constant k of energy transfer h*→g is found to be greatly affected by the luminescence lifetime (phosphorescence lifetime or delayed fluorescence lifetime) τ. That is, the energy transfer efficiency is improved by increasing the luminescence lifetime (phosphorescence lifetime or delayed fluorescence lifetime).

[0084]

Number

[0085]

Number

[0086] Formula (2) is the rate constant k of the Förster mechanism, and formula (3) is the rate constant k of the Dexter mechanism h*→g of the formula.

[0087] In formula (2), ν represents the frequency, and f′ h (ν) represents the normalized emission spectrum of the energy donor (fluorescence spectrum when discussing energy transfer from the singlet excited state, phosphorescence spectrum when discussing energy transfer from the triplet excited state), ε g (ν) represents the molar extinction coefficient of the energy acceptor, N represents Avogadro's number, n represents the refractive index of the medium, R represents the intermolecular distance between the energy donor and the energy acceptor, τ represents the measured lifetime of the excited state (fluorescence lifetime, phosphorescence lifetime), φ represents the emission quantum yield (fluorescence quantum yield when discussing energy transfer from the singlet excited state, phosphorescence quantum yield when discussing energy transfer from the triplet excited state), and K 2 is a coefficient (0 to 4) representing the orientation of the transition dipole moments of the energy donor and the energy acceptor. In the case of random orientation, K 2 = 2 / 3.

[0088] In formula (3), h is Planck's constant, K is a constant having the dimension of energy, ν represents the frequency, and f′ h (ν) represents the normalized emission spectrum of the energy donor (fluorescence spectrum when discussing energy transfer from the singlet excited state, phosphorescence spectrum when discussing energy transfer from the triplet excited state), and ε′ g (ν) represents the normalized absorption spectrum of the energy acceptor, L represents the effective molecular radius, and R represents the intermolecular distance between the energy donor and the energy acceptor.

[0089] Thus, since the energy transfer efficiency is improved by increasing the emission lifetime (phosphorescence lifetime or delayed fluorescence lifetime) of the energy donor, at least one of Compound 131, Compound 132, and Compound 133, preferably any two of them, and most preferably all of them having deuterium can improve the energy transfer efficiency compared to the case where all of them are non-deuterated compounds, and can suppress the degradation of the compound, thereby enabling a highly reliable light-emitting device.

[0090] In Route A2, the exciplex formed from Compound 131 and Compound 132 functions as an energy donor. However, since there may be a path for energy transfer from the triplet excited state of the exciplex through the triplet excited states of Compound 131 and Compound 132, the phosphorescence lifetime or delayed fluorescence lifetime of Compound 131 and Compound 132 constituting the exciplex is important.

[0091] That is, when Compound 131 has deuterium, it is more preferable that the phosphorescence lifetime or delayed fluorescence lifetime of Compound 131 is longer than that of the non-deuterated form of Compound 131. Also, when Compound 132 has deuterium, it is more preferable that the phosphorescence lifetime or delayed fluorescence lifetime of Compound 132 is longer than that of the non-deuterated form of Compound 132. Further, when Compound 133 has deuterium, it is more preferable that the phosphorescence lifetime or delayed fluorescence lifetime of Compound 133 is longer than that of the non-deuterated form of Compound 133.

[0092] In the present specification and the like, the non-deuterated form of a compound having deuterium refers to a compound in which the deuterium of the compound having deuterium is hydrogen.

[0093] As shown in FIG. 3, the phosphorescence lifetime or the delayed fluorescence lifetime is defined as the time from an arbitrary point in the range where the intensity decays in a single exponential function in the decay curve (left figure of FIG. 3) obtained from the transient PL (photoluminescence) with the time t = 0 (right figure of FIG. 3) until the intensity decays to 1 / e times the intensity at the time point of t = 0. Ideally, the emission decays in a single exponential function. Therefore, in FIG. 3, a graph is created with the time when the intensity reaches 50% of the intensity at the start of measurement in the measurement data as t = 0. When the intensity at t = 0 is set to 1, the time until the intensity becomes 1 / e is defined as the phosphorescence lifetime or the delayed fluorescence lifetime.

[0094] The measurement of the phosphorescence lifetime of Compound 131 and Compound 132 can be carried out, for example, at a liquid nitrogen temperature (77K) by installing a liquid nitrogen cooling unit in a fluorometer such as FP-8600 manufactured by JASCO Corporation. The solution preparation of the material is carried out in a glove box. The sample is dissolved in deoxygenated 2-methyltetrahydrofuran (2-MeTHF), stirred with a stirrer at room temperature for about 30 minutes (heating is also carried out for materials that are difficult to dissolve), and a solution with a concentration of about 1.2E -4 M can be prepared and used for measurement.

[0095] Time-resolved measurement can be performed by irradiating the sample cell with excitation light for about 30 seconds, blocking the excitation light with a shutter, and measuring the intensity of the emitted light that decays at intervals of 10 ms. As the wavelength for measuring the phosphorescence lifetime, it is preferable to select a wavelength with as little fluorescence as possible by comparing the emission spectrum measured at low temperature (for example, 77K) (emission spectrum including phosphorescence) and the emission spectrum measured at room temperature (emission spectrum including only fluorescence without phosphorescence). The bandwidths of the excitation light and the measurement light may be about 10 nm. Ideally, the emission decays in a single exponential function. Therefore, the time from when the intensity becomes 50% of the intensity at the start of measurement until the emission intensity decays to 1 / e times can be defined as the phosphorescence emission lifetime.

[0096] For measuring the luminescence lifetime of Compound 133, for example, a picosecond fluorescence lifetime measurement system (manufactured by Hamamatsu Photonics) can be used. The solution of the material is prepared in a glove box of LABstar M13 (1250 / 780) manufactured by MBRAUN. The sample is dissolved in deoxygenated dichloromethane, and a solution with a concentration of 1.5E -5 M can be prepared and used for measurement. The prepared solution is irradiated with a pulsed laser, and the decaying luminescence after the laser irradiation is measured by time-resolved measurement using a streak camera. The pulsed laser (MNL106PD manufactured by LTB) is irradiated onto the prepared solution at a cycle of 10 Hz, and by integrating the repeatedly measured data, data with a high signal-to-noise ratio can be obtained. In this case, the measurement is preferably performed at room temperature (atmosphere maintained at 23 °C).

[0097] Note that the fluorescence lifetime, phosphorescence lifetime, and delayed fluorescence lifetime can be distinguished by the length of the lifetime when time-resolved measurement is performed. The luminescence lifetime with a lifetime of around nanoseconds is the fluorescence lifetime, and the luminescence lifetime with a lifetime of microseconds to milliseconds or more is the phosphorescence lifetime and the delayed fluorescence lifetime.

[0098] For example, when the light emitted by Compound 134 is luminescence in the blue region, that is, when its peak wavelength is typically 450 nm or more and less than 500 nm, it is more preferable that Compound 131 has deuterium and its phosphorescence lifetime or delayed fluorescence lifetime at 77 K is 1.05 times or more the phosphorescence lifetime or delayed fluorescence lifetime of the non-deuterated form of Compound 131 at 77 K. Further, it is more preferable that Compound 132 has deuterium and its phosphorescence lifetime or delayed fluorescence lifetime at 77 K is 1.20 times or more the phosphorescence lifetime or delayed fluorescence lifetime of the non-deuterated form of Compound 132 at 77 K. It is more preferable that Compound 133 has deuterium and its phosphorescence lifetime or delayed fluorescence lifetime at room temperature (any temperature from 290 K to 300 K, preferably 296 K (23 °C)) is 1.02 times or more the phosphorescence lifetime or delayed fluorescence lifetime of the non-deuterated form of Compound 133 at room temperature (any temperature from 290 K to 300 K, preferably 296 K (23 °C)).

[0099] Also, when the light emitted by Compound 134 is light emission in the green region, that is, when its peak wavelength is typically 500 nm or more and 600 nm or less, Compound 131 has deuterium, and its phosphorescence lifetime or delayed fluorescence lifetime at 77K is more preferably 1.50 times or more the phosphorescence lifetime or delayed fluorescence lifetime of the non-deuterated form of Compound 131 at 77K. Compound 132 has deuterium, and its phosphorescence lifetime or delayed fluorescence lifetime at 77K is more preferably 3.00 times or more the phosphorescence lifetime or delayed fluorescence lifetime of the non-deuterated form of Compound 132 at 77K. Compound 133 has deuterium, and its phosphorescence lifetime or delayed fluorescence lifetime at room temperature (any temperature from 290K to 300K, preferably 296K (23°C)) is more preferably 1.02 times or more the phosphorescence lifetime or delayed fluorescence lifetime of the non-deuterated form of Compound 133 at room temperature (any temperature from 290K to 300K, preferably 296K (23°C)).

[0100] Alternatively, in the light-emitting device according to one aspect of the present invention, the reliability is improved in relation to the phosphorescence lifetimes of Compound 131 and Compound 132, that is, the extension of the lifetime of triplet excitons. The extension of the lifetime of triplet excitons is due to the suppression of non-radiative deactivation of triplet excitation energy caused by the suppression of vibrations by deuteration. At this time, since the difference between the T1 level of Compound 131 and the T1 level of Compound 132 is small, the excitation energy is less likely to be biased towards either organic compound, and it is possible to prevent either one from deteriorating significantly, which is preferable because the reliability of the light-emitting device is improved. Specifically, the difference between the T1 level of Compound 131 and the T1 level of Compound 132 is preferably 0.20 eV or less, more preferably 0.15 eV or less, and even more preferably 0.10 eV or less.

[0101] Note that the T1 level can be calculated by measuring the emission spectrum (phosphorescence spectrum) at a measurement temperature of 10 K using a thin film with a 50-nm film of the sample formed on a quartz substrate. For the measurement, it is advisable to use a microscopic PL device LabRAM HR-PL (manufactured by Horiba, Ltd.) and a He-Cd laser (325 nm) as the excitation light. Note that the emission end can be calculated by drawing a tangent at the value where the slope on the short-wavelength side of the peak (or shoulder peak) observed at the shortest wavelength of the emission spectrum (phosphorescence spectrum) is maximized, and then finding the intersection of the tangent with the horizontal axis (wavelength) or the baseline.

[0102] Alternatively, in one aspect of the present invention, it is preferable that the sublimation temperature of Compound 131 and the sublimation temperature of Compound 132 are close to each other. For example, it is preferable that the difference between the 5% weight loss temperature measured by thermogravimetric measurement of Compound 131 and the 5% weight loss temperature measured by thermogravimetric measurement of Compound 132 is 60 °C or less. More preferably, it is 45 °C or less, still more preferably 20 °C or less, and even more preferably 10 °C or less. As a result, since vapor deposition can be performed using a material in which Compound 131 and Compound 132 are mixed, the number of vapor deposition sources can be reduced, and it becomes possible to provide an inexpensive light-emitting device with good characteristics.

[0103] The 5% weight loss temperature can be determined from the relationship between weight and temperature (thermogravimetric measurement) by performing thermogravimetric measurement - differential thermal analysis (TG-DTA: Thermogravimetry - Differential Thermal Analysis). Note that when the pressure for vapor deposition is determined in advance, it is preferable to use the value measured under that pressure.

[0104] Furthermore, it is preferable that the photoluminescence (PL) spectrum of the exciplex formed by Compound 131 and Compound 132 overlaps with the PL spectrum of Compound 133. This is because the driving voltage of the light-emitting device can be reduced due to the excitation energy of the energy donor being close to the excitation energy of Compound 133. Therefore, the difference in the maximum peak wavelength of each is preferably 30 nm or less. Alternatively, it is preferable that the difference between the wavelength of the emission end on the short-wavelength side in the PL spectrum of the exciplex and the wavelength of the emission end on the short-wavelength side in the PL spectrum of Compound 133 is 30 nm or less, as the driving voltage of the light-emitting device can be reduced.

[0105] The PL spectrum of the exciplex is preferably measured using a co-evaporated film of Compound 131 and Compound 132. The sample form when measuring the PL spectrum of Compound 133 may be a thin film or a solution, but a solution is preferred from the perspective of verifying the state of isolated molecules. There is no particular limitation on the solvent of the solution as long as the same solvent is used for comparison, but a solvent with relatively low polarity such as toluene or chloroform is preferred.

[0106] Next, specific examples of host materials that can be used as Compound 131 and Compound 132, phosphorescent materials that can be used as Compound 133, fluorescent materials that can be used as Compound 134, and TADF materials that can be used as Compound 133 or Compound 134 will be described.

[0107] 《Specific Examples of Host Materials》 As described above, the combination of Compound 131 and Compound 132 is preferably a combination capable of forming an exciplex, and it is more preferable that one is a hole-transporting material and the other is an electron-transporting material. Examples of hole-transporting materials include compounds having either or both of a π-electron-rich heteroaromatic ring and an aromatic amine skeleton, and examples of electron-transporting materials include compounds having a π-electron-deficient heteroaromatic ring.

[0108] As the π-electron rich heteroaromatic ring, a condensed aromatic ring containing at least any one of a furan ring, a thiophene ring, and a pyrrole ring is preferable, and specifically, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, or a ring in which an aromatic ring or a heteroaromatic ring is further condensed thereto is preferable.

[0109] Specific examples of the hole transporting material will be described in Embodiment 2.

[0110] Examples of the compound which is a hole transporting material and has deuterium include compounds obtained by deuterating the above-described hole transporting materials. In particular, 9-(2-naphthyl-1,3,4,5,6,7,8-d7)-9'-(phenyl-2,3,4,5,6-d5)-3,3'-bi-9H-carbazole-1,1',2,2',4,4',5,5',6,6',7,7',8,8'-d 14 (Abbreviation: βNCCP-d 26 ), 9-phenyl-9'-(phenyl-2,3,4,5,6-d5)-3,3'-bis(9H-carbazole) (abbreviation: PCCP-d5), etc., which have a carbazole skeleton and have deuterium, have a longer phosphorescence lifetime compared to the non-deuterated form, and thus can enhance the energy transfer efficiency in the light emitting layer 113, and are more preferable.

[0111] Examples of the π-electron deficient heteroaromatic ring include an oxadiazole ring, a triazole ring, a benzimidazole ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a phenanthroline ring, a pyridine ring, a diazine ring (including a pyrimidine ring, a pyrazine ring, and a pyridazine ring), a triazine ring, a furodiazine ring, and the like.

[0112] Specific examples of the electron transporting material will be described in Embodiment 2.

[0113] In addition, examples of the electron transporting material having deuterium include compounds obtained by deuterating the above-described electron transporting material. In particular, 9,9’-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazine-2,4-diyl}bis(9H-carbazole-1,2,3,4,5,6,7,8,1’,2’,3’,4’,5’,6’,7’,8’-d 16 )(abbreviation: SiTrzCz2-d 16 ), 11-[4-(biphenyl-4-yl-2,2’,3,3’,4’,5,5’,6,6’-d9)-6-(phenyl-2,3,4,5,6-d5)-1,3,5-triazin-2-yl]-11,12-dihydro-12-(biphenyl-3-yl)indolo[2,3-a]carbazole-1,2,3,4,5,6,7,8,9,10-d 10 and other compounds having a triazine skeleton and having deuterium, 8-(1,1’:4’,1’’-terphenyl-3-yl-2,4,5,6,2’,3’,5’,6’,2’’,3’’,4’’,5’’,6’’-d 13 )-4-[3-(dibenzothiophen-4-yl-1,2,3,6,7,8,9-d7)phenyl-2,4,6-d3]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm-d 23 ), 8-(1,1’:4’,1’’-terphenyl-3-yl-2,4,5,6,2’,3’,5’,6’,2’’,3’’,4’’,5’’,6’’-d 13 )-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm-d 13 ) and other compounds having a benzofuropyrimidine skeleton and having deuterium are more preferable because they have a longer phosphorescence lifetime compared to the non-deuterated form, and thus can enhance the energy transfer efficiency in the light-emitting layer 113.

[0114] 《Phosphorescent Luminescent Substance》 A phosphorescent substance refers to a compound that exhibits phosphorescence and does not exhibit fluorescence in any temperature range from a low temperature (e.g., 77K) to room temperature (i.e., 77K or higher and 313K or lower). As the phosphorescent substance, it is preferable to have a metal element with a large spin-orbit interaction, and examples include organometallic complexes, metal complexes (platinum complexes), and rare-earth metal complexes. Specifically, transition metal elements are preferable, and in particular, it is preferable to have a platinum group element (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt)). Among them, having iridium can increase the transition probability related to the direct transition between the singlet ground state and the triplet excited state, which is preferable.

[0115] Specific examples of the phosphorescent substance will be described in Embodiment 2.

[0116] Examples of the compound that is a phosphorescent substance and has deuterium include compounds obtained by deuterating the above-mentioned phosphorescent substances. In particular, [2-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mbfpypy-d3)), (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC 2 phenoxy-κC 2}-9-[3,5-Bis(methyl-d3)-4-phenyl-2-pyridinyl-κN]carbazole-2,1-diyl-κC)platinum(II) (abbreviation: Pt(mmtBubOcz35dm4ppy-d6)), {2-(Methyl-d3)-8-[4-(2,2-dimethylpropyl-1,1-d2)-2-pyridinyl-κN]benzofuro[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-Np-d5)), {2-(Methyl-d3)-8-[4-(2,2-dimethylpropyl-1,1-d2)-2-pyridinyl-κN]benzofuro[2,3-b]pyridin-7-yl-κC}bis({2-[(4,5-dimethyl-d6)-2-pyridinyl-κN]-4-(methyl-d3)-3-phenyl}phenyl-κC)iridium(III) (abbreviation: Ir(tm5bpy-d9)2(mbfpypy-Np-d5)), etc. are preferred because they are stable.

[0117] 《Specific Examples of Fluorescent Substances》 Compound 134 is a material having a function of converting singlet excitation energy into light emission. When a fluorescent substance is used as a material having a function of converting singlet excitation energy into light emission, the fluorescent substance is preferably a compound having a light-emitting group in a part of its structure and a protecting group having a function of lengthening the distance between the light-emitting group and another energy donor.

[0118] Here, the lumophore refers to the atomic group (skeleton) that causes luminescence in a fluorescent material. The lumophore generally has a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Further, in another aspect, the lumophore can be regarded as an atomic group (skeleton) containing an aromatic ring on which a transition dipole vector exists on the ring plane. Also, when a single fluorescent material has a plurality of condensed aromatic rings or condensed heteroaromatic rings, among the plurality of condensed aromatic rings or condensed heteroaromatic rings, the skeleton having the lowest S1 level may be considered as the lumophore of the fluorescent material. Further, among the plurality of condensed aromatic rings or condensed heteroaromatic rings, the skeleton having an absorption edge on the longest wavelength side may be considered as the lumophore of the fluorescent material. Also, in some cases, the lumophore of the fluorescent material can be predicted from the shape of the emission spectra of each of the plurality of condensed aromatic rings or condensed heteroaromatic rings.

[0119] Examples of such lumophores include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, a naphthobisbenzofuran skeleton, and the like. In particular, fluorescent materials having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because they have a high fluorescence quantum yield.

[0120] In addition, the substituent used as a protecting group needs to have a triplet excitation energy level higher than the T1 energy level of the lumophore and the host material. Therefore, it is preferable to use a saturated hydrocarbon group. This is because a substituent without a π bond has a high triplet excitation energy level. In addition, a substituent without a π bond has a low function of transporting carriers (electrons or holes). Therefore, the saturated hydrocarbon group can increase the distance between the lumophore and the host material with little influence on the excited state or carrier transportability of the host material. In an organic compound having both a substituent without a π bond and a substituent having a π-conjugated system, the frontier orbitals {HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital)} often exist on the side of the substituent having a π-conjugated system, especially when the lumophore has frontier orbitals. As described later, for energy transfer by the Dexter mechanism, the overlap of the HOMO of the energy donor and the energy acceptor and the overlap of the LUMO are important. Therefore, by using a saturated hydrocarbon group as the protecting group, the distance between the frontier orbitals of the host material as the energy donor and the frontier orbitals of the guest material as the energy acceptor can be increased, and energy transfer by the Dexter mechanism can be suppressed.

[0121] Specific examples of the protecting group include an alkyl group having 1 to 10 carbon atoms. In addition, since the protecting group needs to increase the distance between the lumophore and the host material, a bulky substituent is preferable. Therefore, an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a trialkylsilyl group having 3 to 10 carbon atoms can be preferably used. In particular, as the alkyl group, a bulky branched-chain alkyl group is preferable. In addition, the substituent is particularly preferable because it becomes a bulky substituent when it has a quaternary carbon.

[0122] Also, as described above, it is more preferable that the protecting group is deuterated. When the protecting group has deuterium, specific examples thereof include an alkyl group having 3 to 10 carbon atoms and having deuterium, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms and having deuterium, and a trialkylsilyl group having 3 to 10 carbon atoms and having deuterium.

[0123] Also, it is preferable that there are 5 or more protecting groups for one lumophore. With this configuration, the entire lumophore can be covered with the protecting groups, so that the distance between the host material and the lumophore can be appropriately adjusted. Note that it is more preferable that the protecting group is not directly bonded to the lumophore. For example, the protecting group may be bonded to the lumophore via a divalent or higher substituent such as an arylene group or an amino group. By bonding the protecting group to the lumophore via the substituent, the distance between the lumophore and the host material can be effectively increased. Therefore, when the protecting group is not directly bonded to the lumophore, having 4 or more protecting groups for one lumophore can effectively suppress energy transfer by the Dexter mechanism.

[0124] Specific examples of the fluorescent luminescent substance having a luminescent group and a protecting group having a function of increasing the distance between the luminescent group and another energy donor include N,N'-(2-phenylanthracene-9,10-diyl)-N,N,N',N'-tetrakis(3,5-di-tert-butylphenyl)diamine (abbreviation: 2Ph-mmtBuDPhA2Anth), 2,2',6,6'-tetrakis(3,5-di-tert-butylphenyl)-N,N,N',N'-tetrakis(3,5-di-tert-butylphenyl)-9,9'-bianthracene-10,10'-diamine (abbreviation: 22’66’mmtBuPh-mmtBuDPhA2BANT), N,N'-bis[3,5-bis(1-adamantyl)phenyl]-N,N'-bis(3,5-di-tert-butylphenyl)-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmAdtBuDPhA2Anth-03), N,N'-bis(3,5-di-tert-butylphenyl)-N,N'-bis{3,5-bis[4-(1-adamantyl)phenyl]phenyl}-2,6-diphenylanthracene-9,10-diamine (abbreviation: 2,6Ph-mmAdPtBuDPhA2Anth), N,N'-bis(3,5-di-tert-butylphenyl)-N,N'-bis{3,5-bis[4-(1-adamantyl)phenyl]phenyl}-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmAdPtBuDPhA2Anth), N,N'-bis{3,5-bis(tricyclo[5.2.1.0 2,6(Decan-8-yl)phenyl}-N,N'-bis(3,5-di-tert-butylphenyl)-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmTCDtBuDPhA2Anth), N,N'-bis{3,5-bis(2-bicyclo[2.2.1]heptyl)phenyl}-N,N'-bis(3,5-di-tert-butylphenyl)-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmnbtBuDPhA2Anth), N,N'-bis[3,5-bis(2-adamantyl)phenyl]-N,N'-bis[3,5-bis(3,5-di-tert-butylphenyl)phenyl]-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmAdtBuDPhA2Anth-02), N,N'-bis[3,5-bis(2-adamantyl)phenyl]-N,N'-bis(3,5-di-tert-butylphenyl)-2-phenylanthracene-9,10-diamine (abbreviation: 2Ph-mmAdtBuDPhA2Anth), N,N'-(2-trimethylsilylanthracene-9,10-diyl)-N,N,N',N'-tetrakis(3,5-di-tert-butylphenyl)diamine (abbreviation: 2TMS-mmtBuDPhA2Anth), N,N'-(pyrene-1,6-diyl)bis[N-(2-methylphenyl)-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine] (abbreviation: 1,6oMechBnfAPrn), N,N'-(pyrene-1,6-diyl)bis(N-phenyl-6-trimethylsilylbenzo[b]naphtho[1,2-d]furan-8-amine) (abbreviation: 1,6TMSBnfAPrn), N,N'-(3,8-dicyclohexylpyrene-1,6-diyl)bis[N-phenyl-(6-cyclohexylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: ch-1,6chBnfAPrn), N,N'-bis[9-(3,5-di-tert-butylphenyl)-9H-carbazol-2-yl]-N,N'-diphenyl-naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10mmtBuPCA2Nbf(IV)-02) can be mentioned. Also, materials in which the protecting groups of these compounds are deuterated can be used.

[0125] Moreover, not limited to the above, the fluorescent light-emitting materials listed in Embodiment 2 can be used.

[0126] 《Specific Examples of TADF Materials》 TADF materials are materials that have the function of converting both singlet excitation energy and triplet excitation energy into light emission. Examples of TADF materials include heterocyclic compounds having a π-electron-rich heterocyclic aromatic ring and a π-electron-deficient heterocyclic aromatic ring. Specific examples include 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10’H-spiro[acridine-9,9’-anthracene]-10’-one (abbreviation: ACRSA), and the like. Since the heterocyclic compound has a π-electron-rich heterocyclic aromatic ring and a π-electron-deficient heterocyclic aromatic ring, it has high electron transportability and hole transportability, which is preferable. Among them, among the skeletons having a π-electron-deficient heterocyclic aromatic ring, a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), or a triazine skeleton is preferable because it is stable and has good reliability. Also, among the skeletons having a π-electron-rich heterocyclic aromatic ring, an acridine skeleton, a phenoxazine skeleton, a thiophene skeleton, a furan skeleton, and a pyrrole skeleton are preferable because they are stable and have good reliability, and it is preferable to have any one or more selected from among these skeletons. In addition, as the pyrrole skeleton, an indole skeleton, a carbazole skeleton, and a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton are particularly preferable.In addition, a substance in which a π-electron-excessive heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is particularly preferable because both the donor property of the π-electron-excessive heteroaromatic ring and the acceptor property of the π-electron-deficient heteroaromatic ring are strong, and the difference between the singlet excitation energy level and the triplet excitation energy level becomes small.

[0127] Further, as a TADF material, a condensed heteroaromatic compound containing nitrogen and boron, particularly a compound having a diaza-boranaphtho-anthracene skeleton, is preferable because it has a narrow emission spectrum width and can obtain blue emission with good color purity. Specific examples include 5,9-diphenyl-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene (abbreviation: DABNA1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine-3-amine (abbreviation: DABNA2), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine-7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl)-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: Me-tBu4DABNA), N 7 ,N 7 ,N 13 ,N 13 ,5,9,11,15-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]phenazaborine-7,13-diamine (abbreviation: ν-DABNA), 2-(4-tert-butylphenyl)benzo[5,6]indolo[3,2,1-jk]benzo[b]carbazole (abbreviation: tBuPBibc), and the like.

[0128] In addition to these, as the TADF material, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazol-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3’,2’,1’:8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-G), 9,11-bis[3,6-bis(1,1-dimethylethyl)-9H-carbazol-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3’,2’,1’:8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-Y), etc. can be preferably used.

[0129] A TADF material is a material having a function of converting energy from a triplet excited state to a singlet excited state by reverse intersystem crossing with a small difference between the triplet excitation energy level and the singlet excitation energy level. Therefore, up-conversion (reverse intersystem crossing) from the triplet excited state to the singlet excited state is possible with a small amount of thermal energy, and efficient light emission (fluorescence) from the singlet excited state can be exhibited. Further, as conditions for efficiently obtaining thermally activated delayed fluorescence, the energy difference between the triplet excitation energy level and the singlet excitation energy level is preferably greater than 0 eV and 0.20 eV or less, more preferably greater than 0 eV and 0.10 eV or less.

[0130] In addition, not limited to the above, the TADF materials listed in Embodiment 2 can be used.

[0131] This embodiment can be used in any combination with other embodiments.

[0132] (Embodiment 2) In this embodiment, the configuration of the light-emitting device according to one aspect of the present invention will be described with reference to FIGS. 4(A) to 4(F).

[0133] 〔Basic Structure of Light-Emitting Device〕 The basic structure of the light-emitting device will be described. FIG. 4(A) shows a light-emitting device having an organic compound layer including a light-emitting layer between a pair of electrodes (single structure). Specifically, it has a structure in which the organic compound layer 103 is sandwiched between the first electrode 101 and the second electrode 102.

[0134] Further, FIG. 4(B) shows a light-emitting device having a stacked structure (tandem structure) in which a plurality of (two layers in FIG. 4(B)) organic compound layers (103a, 103b) are provided between a pair of electrodes and a charge generation layer 106 is provided between the organic compound layers. The tandem-structured light-emitting device can realize a highly efficient light-emitting device without changing the current amount.

[0135] The charge generation layer 106 has a function of injecting electrons into one organic compound layer (103a or 103b) and injecting holes into the other organic compound layer (103b or 103a) when a potential difference is generated between the first electrode 101 and the second electrode 102. Therefore, in FIG. 4(B), when a voltage is applied to the first electrode 101 so that the potential becomes 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.

[0136] Note that the charge generation layer 106 preferably has translucency with respect to visible light (specifically, the transmittance of visible light with respect to the charge generation layer 106 is 40% or more) from the viewpoint of light extraction efficiency. Further, the charge generation layer 106 functions even if it has a lower conductivity than the first electrode 101 and the second electrode 102.

[0137] Further, FIG. 4(C) shows the laminated structure of the organic compound layer 103 of the light-emitting device which is one aspect of the present invention. However, 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. Note that the light-emitting layer 113 may have a structure in which a plurality of light-emitting layers having different emission colors are laminated. For example, a light-emitting layer containing a light-emitting substance exhibiting red, a light-emitting layer containing a light-emitting substance exhibiting green, and a light-emitting layer containing a light-emitting substance exhibiting blue may be laminated, or may be laminated via a layer having a carrier transporting property. Alternatively, a combination of a light-emitting layer containing a light-emitting substance exhibiting yellow and a light-emitting layer containing a light-emitting substance exhibiting blue 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 have a structure in which a plurality of light-emitting layers having the same emission color are laminated. For example, a first light-emitting layer containing a light-emitting substance exhibiting blue and a second light-emitting layer containing a light-emitting substance exhibiting blue may be laminated, or may be laminated via a layer having a carrier transporting property. In the case of a structure in which a plurality of light-emitting layers having the same emission color are laminated, the reliability may be improved as compared with a single-layer structure. Also, even in the case of having a plurality of organic compound layers as in the tandem structure shown in FIG. 4(B), each organic compound layer has a structure in which they are sequentially laminated as described above from the anode side. Further, when the first electrode 101 is a cathode and the second electrode 102 is an anode, the lamination order of the organic compound layer 103 is reversed. Specifically, 111 on the first electrode 101 which is a cathode has a structure in which 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.

[0138] The light-emitting layer 113 included in the organic compound layer (103, 103a, 103b) has a light-emitting substance and a plurality of substances appropriately combined, respectively, and can be configured to obtain fluorescence emission or phosphorescence emission that exhibits a desired emission color. Also, the light-emitting layer 113 may have a laminated structure with different emission colors. In this case, different materials may be used for the light-emitting substance and other substances used in each of the laminated light-emitting layers. Further, a configuration may be adopted in which different emission colors can be obtained from the plurality of organic compound layers (103a, 103b) shown in Fig. 4(B). Also in this case, different materials may be used for the light-emitting substance and other substances used in each light-emitting layer.

[0139] Also, in the light-emitting device which is one aspect of the present invention, for example, by using the first electrode 101 shown in Fig. 4(C) as a reflective electrode, the second electrode 102 as a semi-transmissive / semi-reflective electrode, and forming a microcavity structure, the light emission obtained from the light-emitting layer 113 included in the organic compound layer 103 can be resonated between both electrodes, and the light emission emitted from the second electrode 102 can be enhanced. Therefore, it is easy to achieve high definition. Also, since it is possible to enhance the emission intensity in the front direction of a specific wavelength, power consumption can be reduced.

[0140] When the first electrode 101 of the light-emitting device is a reflective electrode having a laminated structure of a conductive material having reflectivity and a conductive material having translucency (transparent conductive film), optical adjustment can be performed by controlling the film thickness of the transparent conductive film. Specifically, it is preferable to adjust so that the optical distance (the product of the film thickness and the refractive index) between the first electrode 101 and the second electrode 102 becomes mλ / 2 (where m is an integer of 1 or more) or in the vicinity thereof with respect to the wavelength λ of the light obtained from the light-emitting layer 113.

[0141] In addition, in order to amplify the desired light (wavelength: λ) obtained from the light-emitting layer 113, the optical distance from the first electrode 101 to the region (light-emitting region) where the desired light of the light-emitting layer 113 can be obtained, and the optical distance from the second electrode 102 to the region (light-emitting region) where the desired light of the light-emitting layer 113 can be obtained are each preferably adjusted to be (2m'+1)λ / 4 (where m' is an integer of 1 or more) or in the vicinity thereof. Here, the light-emitting region refers to the recombination region of holes and electrons in the light-emitting layer 113.

[0142] By performing such optical adjustment, the spectrum of the specific monochromatic light obtained from the light-emitting layer 113 can be narrowed, and light emission with good color purity can be obtained.

[0143] However, in the above case, the optical distance between the first electrode 101 and the second electrode 102 can strictly be said to be the total thickness from the reflection region in the first electrode 101 to the reflection region in the second electrode 102. However, since it is difficult to strictly determine the reflection regions in the first electrode 101 and the second electrode 102, it is assumed that any positions of the first electrode 101 and the second electrode 102 are reflection regions, and it is considered that the above-described effects can be sufficiently obtained. Further, the optical distance between the first electrode 101 and the light-emitting layer from which the desired light can be obtained can strictly be said to be the optical distance between the reflection region in the first electrode 101 and the light-emitting region in the light-emitting layer from which the desired light can be obtained. However, since it is difficult to strictly determine the reflection region in the first electrode 101 and the light-emitting region in the light-emitting layer from which the desired light can be obtained, it is assumed that any position of the first electrode 101 is the reflection region and any position of the light-emitting layer from which the desired light can be obtained is the light-emitting region, and it is considered that the above-described effects can be sufficiently obtained.

[0144] Figure 4(D) shows a modified example of the laminated structure shown in Figure 4(C). Also in this case, it is assumed that the first electrode 101 functions as an anode and the second electrode 102 functions as a cathode. In this modified example, a case having a hole blocking layer and an electron blocking layer is shown. That is, the organic compound layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, an electron blocking layer 116, a light emitting layer 113, a hole blocking layer 117, an electron transport layer 114, and an electron injection layer 115 are sequentially laminated on the first electrode 101.

[0145] The electron blocking layer 116 is provided, for example, for the purpose of preventing electrons from penetrating from the light emitting layer 113 toward the first electrode 101 side. Also, the hole blocking layer 117 is provided, for example, for the purpose of preventing holes from penetrating from the light emitting layer 113 toward the second electrode 102 side. Note that the electron blocking layer 116 can also be regarded as a part of the hole transport layer 112. Also, the hole blocking layer 117 can also be regarded as a part of the electron transport layer 114.

[0146] The light emitting device shown in Figure 4(E) is a light emitting device having a tandem structure. By adopting a tandem structure, a light emitting device capable of high-brightness emission can be obtained. Also, compared with a single structure, the tandem structure can reduce the current required to obtain the same brightness, so the reliability can be improved. Also, the power consumption can be reduced.

[0147] The light emitting device shown in Figure 4(F) is an example of the light emitting device having the tandem structure shown in Figure 4(B). As shown in the figure, it has a structure in which three organic compound layers (103a, 103b, 103c) are laminated with charge generation layers (106a, 106b) interposed therebetween. Note that the three organic compound layers (103a, 103b, 103c) each have a light emitting layer (113a, 113b, 113c), and the emission colors of the respective light emitting layers can be freely combined. For example, the light emitting layer 113a can be blue, the light emitting layer 113b can be any of red, green, or yellow, and the light emitting layer 113c can be blue. However, the light emitting layer 113a can also be red, the light emitting layer 113b can be any of blue, green, or yellow, and the light emitting layer 113c can be red.

[0148] In the light-emitting device which is one aspect of the present invention described above, at least one of the first electrode 101 and the second electrode 102 is an electrode having translucency (such as a transparent electrode, a semi-transmissive / semi-reflective electrode, etc.). When the electrode having translucency is a transparent electrode, the transmittance of visible light of the transparent electrode is 40% or more. In the case of a semi-transmissive / semi-reflective electrode, the reflectance of visible light of the semi-transmissive / semi-reflective electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. Further, these electrodes preferably have a resistivity of 1×10 -2 Ω·cm or less.

[0149] In the light-emitting device which is one aspect of the present invention described above, when one of the first electrode 101 and the second electrode 102 is an electrode having reflectivity (reflective electrode), the reflectance of visible light of the electrode having reflectivity is 40% or more and 100% or less, preferably 70% or more and 100% or less. Further, this electrode preferably has a resistivity of 1×10 -2 Ω·cm or less.

[0150] 〔Specific structure of the light-emitting device〕 Next, the specific structure of the light-emitting device which is one aspect of the present invention will be described. Here, it will be described using FIG. 4(E) having a tandem structure. Note that the configuration of the organic compound layer is the same for the single-structure light-emitting devices shown in FIGS. 4(A) and 4(C). When the light-emitting device shown in FIG. 4(E) has a microcavity structure, the first electrode 101 is formed as a reflective electrode and the second electrode 102 is formed as a semi-transmissive / semi-reflective electrode. Therefore, a desired electrode material can be used singly or in plurality and formed by being single-layered or laminated. Note that the second electrode 102 is formed by appropriately selecting a material after forming the organic compound layer 103b.

[0151] 〔Materials of the light-emitting device〕 〈The first electrode and the second electrode〉 As materials for forming the first electrode 101 and the second electrode 102, the materials shown below can be appropriately combined and used as long as the functions of the above-described both electrodes can be satisfied. For example, metals, alloys, electrically conductive compounds, and mixtures thereof can be appropriately used. Specifically, indium-tin oxide (also referred to as ITO), indium-silicon-tin oxide (also referred to as ITSO), indium-zinc oxide, and indium-tungsten-zinc oxide can be mentioned. In addition, 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 appropriately combined can also be used. In addition, elements belonging to Group 1 or Group 2 of the periodic table not exemplified above (for example, lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these appropriately combined, and other graphene and the like can be used.

[0152] In the light-emitting device shown in FIG. 4(F), when the first electrode 101 is an anode, the hole injection layer 111a and the hole transport layer 112a of the organic compound layer 103a are sequentially formed by vacuum deposition on the first electrode 101. After the organic compound layer 103a and the charge generation layer 106 are formed, the hole injection layer 111b and the hole transport layer 112b of the organic compound layer 103b are similarly sequentially formed on the charge generation layer 106.

[0153] In addition, in each light-emitting device shown in FIG. 4, by using the first electrode 101 as a reflective electrode and the second electrode 102 as a semi-transmissive / semi-reflective electrode to form 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, and the light emitted from the second electrode 102 can be enhanced.

[0154] In addition, when the first electrode 101 of the light-emitting device is a reflective electrode having a laminated structure of a conductive material having reflectivity and a conductive material having translucency (transparent conductive film), optical adjustment can be performed by controlling the film thickness of the transparent conductive film. Specifically, it is preferable to adjust so that the optical distance (the product of the film thickness and the refractive index) between the first electrode 101 and the second electrode 102 becomes mλ / 2 (where m is an integer of 1 or more) or in the vicinity thereof with respect to the wavelength λ of the light obtained from the light-emitting layer 113.

[0155] Further, in order to amplify the desired light (wavelength: λ) obtained from the light-emitting layer 113, the optical distance from the first electrode 101 to the region (light-emitting region) where the desired light of the light-emitting layer 113 is obtained, and the optical distance from the second electrode 102 to the region (light-emitting region) where the desired light of the light-emitting layer 113 is obtained are each preferably adjusted to be (2m'+1)λ / 4 (where m' is an integer of 1 or more) or in the vicinity thereof. Here, the light-emitting region refers to the recombination region of holes and electrons in the light-emitting layer 113.

[0156] By performing such optical adjustment, the spectrum of specific monochromatic light obtained from the light-emitting layer 113 can be narrowed, and light emission with good color purity can be obtained.

[0157] However, in the above case, the optical distance between the first electrode 101 and the second electrode 102 can strictly speaking be the total thickness from the reflection region in the first electrode 101 to the reflection region in the second electrode 102. However, since it is difficult to precisely determine the reflection regions in the first electrode 101 and the second electrode 102, it is assumed that any positions of the first electrode 101 and the second electrode 102 are reflection regions, and it is considered that the above-described effects can be sufficiently obtained. Further, the optical distance between the first electrode 101 and the light-emitting layer from which desired light is obtained can strictly speaking be the optical distance between the reflection region in the first electrode 101 and the light-emitting region in the light-emitting layer from which desired light is obtained. However, since it is difficult to precisely determine the reflection region in the first electrode 101 and the light-emitting region in the light-emitting layer from which desired light is obtained, it is assumed that any position of the first electrode 101 is the reflection region and any position of the light-emitting layer from which desired light is obtained is the light-emitting region, and it is considered that the above-described effects can be sufficiently obtained.

[0158] In the light-emitting device which is one aspect of the present invention described above, at least one of the first electrode 101 and the second electrode 102 is an electrode having translucency (such as a transparent electrode, a semi-transmissive / semi-reflective electrode, etc.). When the electrode having translucency is a transparent electrode, the transmittance of visible light of the transparent electrode is 40% or more. In the case of a semi-transmissive / semi-reflective electrode, the reflectance of visible light of the semi-transmissive / semi-reflective electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. Further, these electrodes preferably have a resistivity of 1×10 -2 Ω·cm or less.

[0159] In the light-emitting device which is one aspect of the present invention described above, when one of the first electrode 101 and the second electrode 102 is an electrode having reflectivity (reflective electrode), the reflectance of visible light of the electrode having reflectivity is 40% or more and 100% or less, preferably 70% or more and 100% or less. Further, this electrode preferably has a resistivity of 1×10 -2 Ω·cm or less.

[0160] 〈Hole injection layer〉 The positive hole injection layer (111, 111a, 111b) is a layer that injects positive holes from the first electrode 101, which is an anode, and the charge generation layer (106, 106a, 106b) into the organic compound layer (103, 103a, 103b), and is a layer containing an organic acceptor material and a material with high positive hole injection properties.

[0161] The organic acceptor material is a material that can generate positive holes in another organic compound by charge separation with other organic compounds having similar LUMO and HOMO levels. Therefore, as the organic acceptor material, compounds having an electron-withdrawing group (halogen group or cyano group) such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives can be used. For example, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene) malononitrile, etc. can be used. Among the organic acceptor materials, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms, such as HAT-CN, are particularly suitable because they have high acceptor properties and stable film quality against heat. In addition, [3]radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group or a cyano group) are preferable because of their very high electron accepting properties. Specifically, α,α’,α’’-1,2,3-cyclopropanetriylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α’,α’’-1,2,3-cyclopropanetriylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α’,α’’-1,2,3-cyclopropanetriylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile], etc. can be used.

[0162] In addition, as a material with high hole injection properties, metal oxides belonging to Groups 4 to 8 in the periodic table (transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc.) can be used. Specifically, molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide can be mentioned. Among these, molybdenum oxide is preferred because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle. In addition, perylene tetracarboxylic acid derivatives such as diquinoxalino[2,3-a:2’,3’-c]phenazine (abbreviation: HATNA), 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2’,3’-c]phenazine (abbreviation: HATNA-F6), 3,4,9,10-perylenetetracarboxylic diimide (abbreviation: PTCDI), 3,4,9,10-perylenetetracarboxyl-bis-benzimidazole (abbreviation: PTCBI), etc., (C 60 -Ih)[5,6]fullerene (abbreviation: C 60 ), (C70-D5h)[5,6]fullerene (abbreviation: C 70) Organic compounds such as phthalocyanine (abbreviation: H2Pc), metal phthalocyanines having copper, zinc, cobalt, iron, chromium, nickel, etc., such as copper phthalocyanine (abbreviation: CuPc), zinc phthalocyanine (abbreviation: ZnPc), cobalt phthalocyanine (abbreviation: CoPc), iron phthalocyanine (abbreviation: FePc), tin phthalocyanine (abbreviation: SnPc), tin oxide phthalocyanine (abbreviation: SnOPc), titanium oxide phthalocyanine (abbreviation: TiOPc), vanadium oxide phthalocyanine (abbreviation: VOPc), and their derivatives can be used. In particular, phthalocyanine-based metal complexes such as CuPc or ZnPc, or 2,3,8,9,14,15-hexafluorodiquinoxalinino[2,3-a:2’,3’-c]phenazine are preferred. Among them, CuPc and ZnPc are preferred because they are inexpensive and have good characteristics. Furthermore, ZnPc has a small diffusion coefficient with respect to silicon, reducing the risk of affecting semiconductor characteristics due to the diffusion of metal into the semiconductor, and is therefore particularly suitable for application to display devices using silicon semiconductors.

[0163] In addition to the above materials, aromatic amine compounds such as 4,4’,4’’-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4’,4’’-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4’-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N’-bis[4-bis(3-methylphenyl)aminophenyl]-N,N’-diphenyl-4,4’-diaminobiphenyl (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), etc., which are low molecular weight compounds, can be used.

[0164] In addition, high molecular weight compounds (oligomers, dendrimers, polymers, etc.) such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N’-[4-(4-diphenylamino)phenyl]phenyl-N’-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), poly[N,N’-bis(4-butylphenyl)-N,N’-bis(phenyl)benzidine] (abbreviation: Poly-TPD), etc. can be used. Alternatively, polymer-based compounds added with acids such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviation: PEDOT / PSS), polyaniline / polystyrene sulfonic acid (PAni / PSS), etc. can also be used.

[0165] In addition, as a material with high hole injection properties, a hole transporting material and a mixed material containing the above-described organic acceptor material (electron-accepting material) can also be used. In this case, electrons are extracted from the hole transporting material by the organic acceptor material, and holes are generated in the hole injection layer 111. Then, the holes are injected into the light-emitting layer 113 through the hole transport layer 112. Note that the hole injection layer 111 may be formed as a single layer composed of a mixed material containing a hole transporting material and an organic acceptor material (electron-accepting material), or may be formed by laminating the hole transporting material and the organic acceptor material (electron-accepting material) as separate layers.

[0166] Note that as the hole transporting material, a substance having a hole mobility with the square root of the electric field strength [V / cm] at 600 being 1×10 -6 cm 2 / Vs or more is preferable. In addition, as long as the substance has higher hole transportability than electrons, other substances can be used.

[0167] In addition, as the hole transporting material, hole transporting materials such as compounds having a π-electron excess type heteroaromatic ring (e.g., carbazole derivatives, furan derivatives, or thiophene derivatives) and aromatic amines (organic compounds having an aromatic amine skeleton) are preferable.

[0168] Note that examples of the carbazole derivative (organic compound having a carbazole ring) include bicarbolyl derivatives (e.g., 3,3'-bicarbolyl derivatives) and aromatic amines having a carbazolyl group.

[0169] Examples of the bicarbazole derivative (for example, 3,3'-bicarbazole derivative) specifically include 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: βNCCP), and the like.

[0170] Examples of aromatic amines having a carbazolyl group include, specifically, 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]bis(9,9-dimethyl-9H-fluoren-2-yl)amine (abbreviation: PCBFF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-(9,9-dimethyl-9H-fluoren-2-yl)-9,9-dimethyl-9H-fluoren-4-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-diphenyl-9H-fluoren-2-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-diphenyl-9H-fluoren-4-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi(9H-fluorene)-2-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi(9H-fluorene)-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':3',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-2-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':4',1''-terphenyl-4-yl)-9,9-Dimethyl-9H-fluorene-2-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1’:3’,1’’-terphenyl-4-yl)-9,9-dimethyl-9H-fluorene-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1’:4’,1’’-terphenyl-4-yl)-9,9-dimethyl-9H-fluorene-4-amine, 4,4’-diphenyl-4’’-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4’-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4’-di(1-naphthyl)-4’’-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: PCA1BP), N,N’-bis(9-phenylcarbazol-3-yl)-N,N’-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N’,N’’-triphenyl-N,N’,N’’-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9’-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-Bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), N-(9,9-spirobi[9H-fluorene]-2-yl)-N,9-diphenylcarbazol-3-amine (abbreviation: PCASF), N-(4-biphenyl)-4-(carbazol-9-yl)phenylaniline (abbreviation: YGA1BP), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), 4,4',4''-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), etc. can be mentioned.,

[0171] In addition to the above, examples of the carbazole derivative include 9-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]phenanthrene (abbreviation: PCPPn), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviation: PSiCzCz), 9'-phenyl-9'H-9,3':6',9''-tercarbazole (abbreviation: PSiCzGI), 3,9-bis(9-phenyl-9H-carbazol-3-yl)-9H-carbazole (abbreviation: PCCzPC), 9-(biphenyl-4-yl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: PCCzBP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1''-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1''-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1''-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylene-2-yl)-3,3'-9H,9’H-carbazole, 9-phenyl-9’-(triphenylene-2-yl)-3,3’-9H,9’H-carbazole (abbreviation: PCCzTp), 9,9’-bis(triphenylene-2-yl)-3,3’-9H,9’H-carbazole, 9-(4-biphenyl)-9’-(triphenylene-2-yl)-3,3’-9H,9’H-carbazole, 9-(triphenylene-2-yl)-9’-[1,1’:3’,1”-terphenyl]-4-yl-3,3’-9H,9’H-carbazole and the like can be mentioned.,

[0172] In addition, as the furan derivative (organic compound having a furan ring), specifically, 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II) and the like can be mentioned.,

[0173] In addition, as the thiophene derivative (organic compound having a thiophene ring), specifically, 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), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV) and other organic compounds having a thiophene ring can be mentioned.,

[0174] Also, as the aromatic amine, specifically, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluorene-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluorene-2-yl)amino]-9H-fluorene-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-fluorene-7-yl)diphenylamine (abbreviation: DPNF), N-(9,9-spirobi[9H-fluorene]-2-yl)-N,N'N'-triphenyl-1,4-phenylenediamine (abbreviation: DPASF), N,N'-diphenyl-N,N'-bis(4-diphenylaminophenyl)spirobi[9H-fluorene]-2,7-diamine (abbreviation: DPA2SF), 4,4',4''-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: m-MTDATA), N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), DNTPD, 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophene-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)phenyl]tris(biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazol-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-Dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-1-amine, etc. are mentioned.,

[0175] In addition, as the hole transporting material, polymer compounds (oligomers, dendrimers, polymers, etc.) such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD), etc. can be used. Or, polymer compounds added with acids such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviation: PEDOT / PSS), polyaniline / polystyrene sulfonic acid (PAni / PSS), etc. can also be used.,

[0176] However, the hole transport material is not limited to the above, and one or a combination of a variety of known materials can also be used as the hole transport material. When the above hole transport material is used in the light-emitting layer, a compound in which some or all of the hydrogen is replaced with deuterium can also be used. In this case, the energy transfer efficiency in the light-emitting layer can be increased, and the deterioration of the compound can be suppressed, so that the reliability of the light-emitting device can be improved.

[0177] Note that the hole injection layers (111, 111a, 111b) can be formed using various known film-forming methods. For example, they can be formed using a vacuum evaporation method.

[0178] 〈Hole Transport Layer〉 The hole transport layers (112, 112a, 112b) are layers that transport the holes injected from the first electrode 101 to the light-emitting layers (113, 113a, 113b) by the hole injection layers (111, 111a, 111b). Note that the hole transport layers (112, 112a, 112b) are layers containing a hole transport material. Therefore, the hole transport material that can be used for the hole injection layers (111, 111a, 111b) can be used for the hole transport layers (112, 112a, 112b).

[0179] In the light-emitting device which is one aspect of the present invention, the same organic compound as that of the hole transport layers (112, 112a, 112b) can be used for the light-emitting layers (113, 113a, 113b). Using the same organic compound for the hole transport layers (112, 112a, 112b) and the light-emitting layers (113, 113a, 113b) is more preferable because the holes can be efficiently transported from the hole transport layers (112, 112a, 112b) to the light-emitting layers (113, 113a, 113b).

[0180] 〈Electron Blocking Layer〉 The electron blocking layer 116 is provided for the purpose of preventing electrons from tunneling from the light emitting layer 113 to the first electrode 101 side. As the electron blocking layer 116, a material having excellent hole transporting properties, low electron transporting properties, and a high LUMO level is suitable. From among the substances listed as materials for the hole transporting layer 112 described above, a material having a LUMO level higher than the LUMO level of the material (at least the host material) constituting the light emitting layer, preferably a material 0.30 eV or more higher, is preferably used for formation. Note that since the electron blocking layer transports holes, it can also be regarded as a part of the hole transporting layer 112.

[0181] 〈Light Emitting Layer〉 The light emitting layers (113, 113a, 113b) have the configuration described in Embodiment 1 and are layers containing a light emitting substance. As the light emitting substance that can be used for the light emitting layers (113, 113a, 113b), substances exhibiting emission colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red can be appropriately used. Further, when there are a plurality of light emitting layers, a configuration in which different emission colors are exhibited by using different light emitting substances for each light emitting layer (for example, white light emission obtained by combining emission colors in a complementary color relationship) can be adopted. Also, when there are a plurality of light emitting layers, each light emitting layer can have the same emission color. In the case of a configuration in which a plurality of light emitting layers having the same emission color are stacked, the reliability may be improved compared to a single layer configuration. Furthermore, a stacked structure in which one light emitting layer has different light emitting substances may be adopted.

[0182] 《Material Having a Function of Converting Singlet Excitation Energy into Light Emission》 Examples of materials that can be used in the light-emitting layer (113, 113a, 113b) and have the function of converting singlet excitation energy into light emission include substances that emit the following fluorescence (fluorescent substances). For example, pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, naphthalene derivatives, etc. are included. In particular, pyrene derivatives are preferred because of their high luminescence quantum yield. Specific examples of pyrene derivatives include N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N,N'-bis(dibenzothiophene-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviation: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), etc.

[0183] In addition, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenyl-4,4'-stilbenediamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), 4-[4-(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), N,N''-(2-tert-butylanthracene-9,10-diyl-di-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), etc. can be used.

[0184] Also, 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-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N’-diphenylquinacridone (abbreviation: DPQd), Rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N’,N’-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N’,N’-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 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]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), 1,6BnfAPrn-03, N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazol-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. can be mentioned. In particular, pyrenediamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, 1,6BnfAPrn-03, etc. can be used.,

[0185] 《Material having a function of converting triplet excitation energy into light emission》 Next, examples of materials having a function of converting triplet excitation energy into light emission that can be used in the light-emitting layer 113 include substances that emit phosphorescence (phosphorescent substances).

[0186] A phosphorescent substance refers to a compound that exhibits phosphorescence and does not exhibit fluorescence in any temperature range from low temperature (e.g., 77K) to room temperature or lower (i.e., 77K or higher and 313K or lower). As the phosphorescent substance, it preferably has a metal element with a large spin-orbit interaction, and examples include organometallic complexes, metal complexes (platinum complexes), rare earth metal complexes, etc. Specifically, transition metal elements are preferred, and in particular, it is preferable to have a platinum group element (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt)). Among them, having iridium can increase the transition probability related to the direct transition between the singlet ground state and the triplet excited state, which is preferable.

[0187] Phosphorescent Substances (450 nm or more and 570 nm or less: Blue or Green) Examples of phosphorescent substances that exhibit blue or green and have a peak wavelength of the emission spectrum of 450 nm or more and 570 nm or less include the following substances.

[0188] For example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b)3]), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPr5btz)3]), such organic iridium complexes having a 4H-triazole ring, tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), such organic iridium complexes having a 1H-triazole ring, fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), such organic iridium complexes having an imidazole ring, bis[2-(4’,6’-difluorophenyl)pyridinato-N,C2’]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4’,6’-difluorophenyl)pyridinato-N,C2’]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3’,5’-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4’,6’-difluorophenyl)pyridinato-N,C 2’Organoiridium complexes having a phenylpyridine derivative having an electron-withdrawing group as a ligand, such as iridium(III) acetylacetonate (abbreviation: FIr(acac)), (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC 2}phenoxy-κC 2}-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl-κC 1 )platinum(II) (abbreviation: PtON-TBBI) and other organoplatinum complexes and the like can be mentioned.

[0189] 《Phosphorescent substance (495 nm or more and 590 nm or less: green or yellow)》 Examples of the phosphorescent substance that exhibits green or yellow and has a peak wavelength of the emission spectrum in the range of 495 nm or more and 590 nm or less include the following substances.

[0190] For example, organic iridium complexes having a pyrimidine ring such as tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]); organic iridium complexes having a pyrazine ring such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]); tris(2-phenylpyridinato-N,C 2’ )iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2’ ) iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-phenyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(4dppy)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC], [2-d3-methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridin-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), {2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofuro[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-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridin-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mbfpypy-d3)), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mdppy)) and other organic iridium complexes having a pyridine ring, bis(2,4-diphenyl-1,3-oxazolato-N,C 2’)Iridium(III) acetylacetonate (abbreviation: [Ir(dpo)2(acac)]), bis{2-[4’-(perfluorophenyl)phenyl]pyridinato-N,C 2’}iridium(III) acetylacetonate (abbreviation: [Ir(p-PF-ph)2(acac)]), bis(2-phenylbenzothiazolato-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(bt)2(acac)]), etc. In addition to organometallic complexes, rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]) can be mentioned.

[0191] {Phosphorescent substances (570 nm or more and 750 nm or less: yellow or red)} Examples of phosphorescent substances that exhibit yellow or red and have a peak wavelength of the emission spectrum in the range of 570 nm or more and 750 nm or less include the following substances.

[0192] For example, organometallic complexes having a pyrimidine ring 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)]), (dipivaloylmethanato)bis[4,6-di(naphthalen-1-yl)pyrimidinato]iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), (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)]), bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κ 2O,O’)-iridium(III) (abbreviation: [Ir(dmdppr-P)2(dibm)]), bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O’)-iridium(III) (abbreviation: [Ir(dmdppr-dmCP)2(dpm)]), bis{2-[5-(2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]-4,6-dimethylphenyl-κC}(2,2’,6,6’-tetramethyl-3,5-heptanedionato-κ 2 O,O’)-iridium(III) (abbreviation: [Ir(dmdppr-dmp)2(dpm)]), (acetylacetonato)bis(2-methyl-3-phenylquinoxalinato-N,C 2’ )iridium(III) (abbreviation: [Ir(mpq)2(acac)]), (acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C 2’ )iridium(III) (abbreviation: [Ir(dpq)2(acac)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), and organometallic complexes having a pyrazine ring such as tris(1-phenylisoquinolinato-N,C 2’ )iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), and bis[4,6-dimethyl-2-(2-quinolyl-κN)phenyl-κC](2,4-pentanedionato-κ 2Organometallic complexes having a pyridine ring such as iridium(III) (abbreviation: [Ir(dmpqn)2(acac)]), platinum complexes such as platinum(II) 2,3,7,8,12,13,17,18 - octaethyl - 21H,23H - porphyrin (abbreviation: [PtOEP]), rare earth metal complexes such as tris(1,3 - diphenyl - 1,3 - propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), and tris[1 - (2 - thenoyl)-3,3,3 - trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]) can be mentioned.

[0193] 《TADF Materials》 As TADF materials, the following materials can be used. A TADF material is a material in which the energy difference between the S1 level and the T1 level is small (preferably 0.20 eV or less), and the triplet excited state can be up - converted (reverse intersystem crossing) to the singlet excited state by a small amount of thermal energy, and efficiently exhibits luminescence (fluorescence) from the singlet excited state. Also, as conditions for efficiently obtaining thermally activated delayed fluorescence, the energy difference between the triplet excited energy level and the singlet excited energy level is 0.00 eV or more and 0.20 eV or less, preferably 0.00 eV or more and 0.10 eV or less. Further, the delayed fluorescence in a TADF material refers to luminescence having a spectrum similar to that of normal fluorescence but with a significantly longer lifetime. The lifetime is 1×10 -6 seconds or more, or 1×10 -3 seconds or more.

[0194] Note that TADF materials can also be used as electron - transporting materials, hole - transporting materials, and host materials.

[0195] Examples of the TADF materials include fullerenes and their derivatives, acridine derivatives such as proflavine, eosin, etc. Further, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd), etc. are included. Examples of the metal-containing porphyrins include protoporphyrin-tin fluoride complex (abbreviation: SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (abbreviation: SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (abbreviation: SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (abbreviation: SnF2(OEP)), etioporphyrin-tin fluoride complex (abbreviation: SnF2(Etio I)), octaethylporphyrin-platinum chloride complex (abbreviation: PtCl2OEP), etc.

[0196]

Chem.

[0197] In addition, π-electron rich heteroaromatic compounds such as 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10’H-spiro[acridine-9,9’-anthracene]-10’-one (abbreviation: ACRSA), 4-(9’-phenyl-3,3’-bi-9H-carbazol-9-yl)benzofuro[3,2-d]pyrimidine (abbreviation: 4PCCzBfpm), 4-[4-(9’-phenyl-3,3’-bi-9H-carbazol-9-yl)phenyl]benzofuro[3,2-d]pyrimidine (abbreviation: 4PCCzPBfpm), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9’-phenyl-2,3’-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), etc., and heteroaromatic compounds having π-electron deficient heteroaromatic compounds may also be used.

[0198] In addition, a substance in which a π-electron rich heteroaromatic compound and a π-electron deficient heteroaromatic compound are directly bonded is particularly preferable because both the donor property of the π-electron rich heteroaromatic compound and the acceptor property of the π-electron deficient heteroaromatic compound are enhanced, and the energy difference between the singlet excited state and the triplet excited state becomes small. Further, as the TADF material, a TADF material (TADF100) in which the singlet excited state and the triplet excited state are in a thermal equilibrium state may be used. Since such a TADF material has a short emission lifetime (excitation lifetime), it is possible to suppress the efficiency decrease in the high-luminance region in the light-emitting device.

[0199] [Chemical formula]

[0200] In addition to the above, examples of the material having a function of converting triplet excitation energy into light emission include nanostructures of transition metal compounds having a perovskite structure. In particular, nanostructures of metal halide perovskites are preferable. As the nanostructure, nanoparticles and nanorods are preferable.

[0201] In the light-emitting layer (113, 113a, 113b, 113c), as the organic compound (host material, etc.) used in combination with the above-described light-emitting substance (guest material), a substance having an energy gap larger than the energy gap of the light-emitting substance (guest material) may be selected and used singly or in combination of two or more.

[0202] [Host Material for Fluorescent Emission] When the light-emitting substance used in the light-emitting layer (113, 113a, 113b, 113c) is a fluorescent light-emitting substance, as the organic compound (host material) to be combined, it is preferable to use an organic compound having a large energy level in the singlet excited state and a small energy level in the triplet excited state, or an organic compound having a high fluorescence quantum yield. Therefore, as long as it is an organic compound that satisfies such conditions, hole-transporting materials (described above), electron-transporting materials (described later), etc. shown in this embodiment can be used. When the above hole-transporting material is used in the light-emitting layer, a compound in which part or all of the hydrogen is substituted with deuterium can also be used. In this case, the energy transfer efficiency in the light-emitting layer can be increased, the deterioration of the compound can be suppressed, and thus the reliability of the light-emitting device can be increased.

[0203] Although it overlaps with some of the specific examples described above, from the viewpoint of a preferable combination with the light-emitting substance (fluorescent light-emitting substance), examples of the organic compound (host material) include condensed polycyclic aromatic compounds such as anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives.

[0204] Specific examples of the organic compound (host material) preferably used in combination with the fluorescent substance include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9,10-diphenylanthracene (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazole-3-amine (abbreviation: PCAPBA), N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N’,N’,N’’,N’’,N’’’,N’’’-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenz[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-[4’-(9-phenyl-9H-fluoren-9-yl)biphenyl-4-yl]anthracene (abbreviation: FLPPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,β-ADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 2,9-di(1-naphthyl)-10-phenylanthracene (abbreviation: 2αN-αNPhA), 9-(1-naphthyl)-10-[3-(1-naphthyl)phenyl]anthracene (abbreviation: αN-mαNPAnth), 9-(2-naphthyl)-10-[3-(1-naphthyl)phenyl]anthracene (abbreviation: βN-mαNPAnth), 9-(1-naphthyl)-10-[4-(1-naphthyl)phenyl]anthracene (abbreviation: αN-αNPAnth), 9-(2-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: βN-βNPAnth), 2-(1-naphthyl)-9-(2-naphthyl)-10-phenylanthracene (abbreviation: 2αN-βNPhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthracenyl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3), 5,12-diphenyltetracene, 5,12-bis(biphenyl-2-yl)tetracene, and the like.

[0205] 《Host Material for Phosphorescent Emission》 Also, when the luminescent material used in the light-emitting layer (113, 113a, 113b, 113c) is a phosphorescent material, an organic compound (host material) to be combined may be selected such that its triplet excitation energy (energy difference between the ground state and the triplet excited state) is larger than that of the luminescent material. When a plurality of organic compounds (for example, a first host material, and a second host material (or assist material), etc.) are used in combination with the luminescent material to form an exciplex, it is preferable to mix and use these plurality of organic compounds with the phosphorescent material.

[0206] With such a configuration, efficient light emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the exciplex to the luminescent material, can be obtained. As for the combination of a plurality of organic compounds, those that easily form an exciplex are preferable, and it is particularly preferable to combine a compound that easily receives holes (hole-transporting material) and a compound that easily receives electrons (electron-transporting material).

[0207] Incidentally, although overlapping with some of the specific examples described above, from the perspective of a preferable combination with a light-emitting substance (phosphorescent light-emitting substance), examples of the organic compound (host material, assist material) include aromatic amines (organic compounds having an aromatic amine skeleton), carbazole derivatives (organic compounds having a carbazole ring), dibenzothiophene derivatives (organic compounds having a dibenzothiophene ring), dibenzofuran derivatives (organic compounds having a dibenzofuran ring), oxadiazole derivatives (organic compounds having an oxadiazole ring), triazole derivatives (organic compounds having a triazole ring), benzimidazole derivatives (organic compounds having a benzimidazole ring), quinoxaline derivatives (organic compounds having a quinoxaline ring), dibenzoquinoxaline derivatives (organic compounds having a dibenzoquinoxaline ring), pyrimidine derivatives (organic compounds having a pyrimidine ring), triazine derivatives (organic compounds having a triazine ring), pyridine derivatives (organic compounds having a pyridine ring), bipyridine derivatives (organic compounds having a bipyridine ring), phenanthroline derivatives (organic compounds having a phenanthroline ring), phthalazine derivatives (organic compounds having a phthalazine ring), zinc and aluminum-based metal complexes, and the like.

[0208] Incidentally, among the above organic compounds, specific examples of aromatic amines and carbazole derivatives, which are organic compounds with high hole-transporting properties, are the same as the specific examples of the above-described hole-transporting materials, and all of these are preferable as host materials.

[0209] Among the above organic compounds, specific examples of dibenzothiophene derivatives and dibenzofuran derivatives, which are organic compounds with high hole-transporting properties, include 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), DBT3P-II, 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4-[3-(triphenylene-2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II), etc. All of these are preferable as host materials.

[0210] In addition, metal complexes having oxazole-based and thiazole-based ligands such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) are also mentioned as preferable host materials.

[0211] Among the above organic compounds, specific examples of organic compounds with high electron transporting properties, such as oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, quinazoline derivatives, phenanthroline derivatives, etc., include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2’,2’’-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4’-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and other organic compounds containing a heteroaromatic ring having an azole ring, bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2’-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), and other organic compounds containing a heteroaromatic ring having a phenanthroline ring, 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3’-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3’-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,Quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzothiophene (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzothiophene (abbreviation: 6mDBTPDBq-II), 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN), 2-[4’-(9-phenyl-9H-carbazole-3-yl)-3,1’-biphenyl-1-yl]dibenzothiophene (abbreviation: 2mpPCBPDBq), and other organic compounds containing a heteroaromatic ring having a dibenzoquinoxaline ring, etc. are mentioned, and all of these are preferable as host materials.,

[0212] Among the above organic compounds, specific examples of organic compounds with high electron transport properties, such as pyridine derivatives, diazine derivatives (including pyrimidine derivatives, pyrazine derivatives, pyridazine derivatives), triazine derivatives, and furodiazine derivatives, include 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9’-phenyl-2,3’-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 9,9’-[pyrimidine-4,6-diylbis(biphenyl-3,3’-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 2-[3’-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 9-[3’-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3’-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 11-[3’-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr), 11-[3’-(dibenzothiophen-4-yl)biphenyl-4-yl]phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine, 11-[3’-(9H-carbazol-9-yl)biphenyl-3-yl]phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine, 12-(9’-phenyl-3,3’-bi-9H-carbazol-9-yl)phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine (abbreviation: 12PCCzPnfpr), 9-[3’-(9-phenyl-9H-carbazol-3-yl)biphenyl-4-yl]naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 9pmPCBPNfpr), 9-(9’-phenyl-3,3’-bi-9H-carbazol-9-yl)naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 9PCCzNfpr), 10-(9’-phenyl-3,3’-bi-9H-carbazol-9-yl)naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 10PCCzNfpr), 9-[3’-(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)biphenyl-3-yl]naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 9mBnfBPNfpr), 9-{3-[6-(9,9-dimethylfluoren-2-yl)dibenzothiophen-4-yl]phenyl}naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 9mFDBtPNfpr), 9-[3’-(6-phenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr-02), 9-[3-(9’-phenyl-3,3’-bi-9H-carbazol-9-yl)phenyl]naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 9mPCCzPNfpr), 9-[3’-(2,8-diphenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1’,2’:4,5]furo[2,3-b]pyrazine, 11-[3’-(2,8-diphenyldibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine, 5-[3-(4,6-diphenyl-1,3,(5-Triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-inden[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), 2-(Biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2,6-Bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 3-[9-(4,6-Diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(Biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1''-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 6-(Biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), and other organic compounds containing a heteroaromatic ring having a diazine ring, etc. are mentioned, and all of these are preferable as host materials.,

[0213] Among the above organic compounds, specific examples of metal complexes, which are organic compounds with high electron transporting properties, include zinc-based or aluminum-based metal complexes such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), and other metal complexes having a quinoline ring or a benzoquinoline ring. All of these are preferable as host materials.

[0214] In addition, polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) are also preferable as host materials.

[0215] Furthermore, bipolar 9-phenyl-9'-(4-phenyl-2-quinazolinyl)-3,3'-bi-9H-carbazole (abbreviation: PCCzQz), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzof[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-inden[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-(biphenyl-3-yl)indolo[2,3-a]carbazole (abbreviation: BP-mBPIcz(II)Tzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenyl-indolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenz[c,g]carbazole (abbreviation: PC-cgDBCzQz), 3-{3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]phenyl}-9-phenyl-9H-carbazole (abbreviation: mPCPDBfTzn), 9,9'-[6-(biphenyl-4-yl)-2-phenyl-1,3,5-triazine-4,3''-diyl]bis(9H-carbazole) (abbreviation: Cz-pmCzBPTzn), 3-phenyl-9-[4-phenyl-6-(9-phenyl-3-dibenzofuranyl)-1,3,5-triazin-2-yl]-9H-carbazole (abbreviation: PDBf-PCzTzn), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzothienyl]-2-phenyl-9H-carbazole (abbreviation: PCzDBtTzn), and other organic compounds having a diazine ring or a triazine ring can also be used as a host material.

[0216] 〈Hole-blocking layer〉 The positive hole blocking layer 117 is provided for the purpose of preventing the positive holes from penetrating from the light emitting layer 113 toward the second electrode 102. As the positive hole blocking layer 117, a material having excellent electron transporting property, low positive hole transporting property, and a low HOMO level is preferable. Among the substances that can be used as the material of the electron transporting layer 114 described later, a material having a HOMO level lower than the HOMO level of the material (at least the host material) constituting the light emitting layer, preferably a material having a HOMO level 0.30 eV or more lower, is preferably used to form the layer. Note that, since the positive hole blocking layer transports electrons, it can also be regarded as a part of the electron transporting layer 114.

[0217] 〈Electron Transport Layer〉 The electron transport layers (114, 114a, 114b) are layers that transport electrons injected from the second electrode 102 and the charge generation layers (106, 106a, 106b) by the electron injection layers (115, 115a, 115b) described later to the light emitting layers (113, 113a, 113b). Note that, in a light emitting device which is one aspect of the present invention, the heat resistance can be improved by the electron transport layer having a stacked structure. Further, the electron transporting material used for the electron transport layers (114, 114a, 114b) has an electron mobility with the square root of the electric field strength [V / cm] at 600 being -6 cm 2 / Vs or more. As long as the material has higher electron transporting property than positive holes, other materials can be used. Further, the electron transport layers (114, 114a, 114b) can function even as a single layer, but may have a stacked structure of two or more layers. Note that, since the above-described mixed material has heat resistance, by performing a photolithography process on the electron transport layer using this material, the influence on the device characteristics due to the heat process can be suppressed.

[0218] 《Electron Transporting Material》 As the electron transporting material that can be used for the electron transport layer (114, 114a, 114b), an organic compound with high electron transporting property can be used, for example, a heteroaromatic compound can be used. Here, the heteroaromatic compound is a cyclic compound containing at least two different elements in the ring. The ring structure includes a 3-membered ring, 4-membered ring, 5-membered ring, 6-membered ring, etc., and particularly a 5-membered ring or 6-membered ring is preferable. As the elements contained, a heteroaromatic compound containing any one or more of nitrogen, oxygen, or sulfur in addition to carbon is preferable. Particularly, a heteroaromatic compound containing nitrogen (nitrogen-containing heteroaromatic compound) is preferable, and it is preferable to use an electron transporting material such as a nitrogen-containing heteroaromatic compound or a compound having a π-electron deficient heteroaromatic ring containing the same.

[0219] In addition, for this electron transport material, a material different from the material used for the light emitting layer can also be used. Not all excitons generated by the recombination of carriers in the light emitting layer can contribute to light emission, and they may diffuse into the layer in contact with or in the vicinity of the light emitting layer. In order to avoid this phenomenon, it is preferable that the energy level (lowest singlet excitation energy level or lowest triplet excitation energy level) of the material used for the layer in contact with or in the vicinity of the light emitting layer is higher than that of the material used for the light emitting layer. Therefore, by using a material different from the material used for the light emitting layer for the electron transport material, a highly efficient device can be obtained.

[0220] The heteroaromatic compound is an organic compound having at least one heteroaromatic ring.

[0221] The heteroaromatic ring has any one of a pyridine ring, diazine ring, triazine ring, or azole ring, oxazole ring, or thiazole ring. The heteroaromatic ring having a diazine ring includes a heteroaromatic ring having a pyrimidine ring, pyrazine ring, or pyridazine ring. The heteroaromatic ring having an azole ring includes a heteroaromatic ring having an imidazole ring, triazole ring, or oxadiazole ring.

[0222] The complex aromatic ring includes a condensed complex aromatic ring having a condensed ring structure. Examples of the condensed complex aromatic ring include a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a phenanthroline ring, a phthalazine ring, a benzimidazole ring, and the like.

[0223] Examples of the complex aromatic compound include, among complex aromatic compounds containing any one or more of nitrogen, oxygen, or sulfur in addition to carbon, complex aromatic compounds having a 5-membered ring structure such as a complex aromatic compound having an imidazole ring, a complex aromatic compound having a triazole ring, a complex aromatic compound having an oxazole ring, a complex aromatic compound having an oxadiazole ring, a complex aromatic compound having a thiazole ring, and a complex aromatic compound having a benzimidazole ring.

[0224] Examples of the complex aromatic compound having a 6-membered ring structure among complex aromatic compounds containing any one or more of nitrogen, oxygen, or sulfur in addition to carbon include a complex aromatic compound having a pyridine ring, a diazine ring (including a pyrimidine ring, a pyrazine ring, a pyridazine ring, etc.), a triazine ring, and a complex aromatic compound having a complex aromatic ring such as an azole ring. In addition, complex aromatic compounds having a bipyridine structure and a terpyridine structure, etc., which are included in complex aromatic compounds having a structure in which a pyridine ring is linked, are exemplified.

[0225] Furthermore, examples of the complex aromatic compound having a condensed ring structure partially including the above 6-membered ring structure include a complex aromatic compound having a condensed complex aromatic ring such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a phenanthroline ring, a phthalazine ring (including a structure in which an aromatic ring is condensed to the furan ring of the phthalazine ring), and a benzimidazole ring.

[0226] Specific examples of the heteroaromatic compound having a 5-membered ring structure (including an azole ring (imidazole ring, triazole ring, oxadiazole ring), oxazole ring, thiazole ring, benzimidazole ring, etc.) include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), 2,2’,2’’-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4’-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and the like.

[0227] Specific examples of the heteroaromatic compound having the above six-membered ring structure (including a heteroaromatic ring having a pyridine ring, a diazine ring, a triazine ring, etc.) include heteroaromatic compounds containing a heteroaromatic ring having a pyridine ring such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), etc.; 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-inden[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), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1''-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), heteroaromatic compounds containing a heteroaromatic ring having a triazine ring such as mFBPTzn; 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-Bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 4,6mCzBP2Pm, 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 4-[3-(dibenzothiophen-4-yl)phenyl]-8-(naphthalen-2-yl)-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8βN-4mDBtPBfpm), 8BP-4mDBtPBfpm, 9mDBtBPNfpr, 9pmDBtBPNfpr, 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3’-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1’,2’:4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2’-binaphthalene)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 8-(1,1’:4’,1’’-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), and other heteroaromatic compounds containing a heteroaromatic ring having a diazine (pyrimidine) ring, etc. are included. The aromatic compounds containing the above heteroaromatic ring include heteroaromatic compounds having a condensed heteroaromatic ring.,

[0228] In addition, diazine (pyrimidine) ring-containing heteroaromatic compounds such as 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 6,6'(P-Bqn)2BPy), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm); heteroaromatic compounds containing a heteroaromatic ring having a triazine ring such as 2,4,6-tris(3'-(pyridine-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviation: TmPPPyTz), 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tz), 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), etc. are included.

[0229] Specific examples of the heteroaromatic compound having a condensed ring structure partially including the above-mentioned 6-membered ring structure (heteroaromatic compound having a condensed ring structure) include bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), heteroaromatic compounds having a quinoxaline ring such as 2mpPCBPDBq, and the like.

[0230] In addition to the complex aromatic compounds shown above, the following metal complexes can also be used for the electron transport layer (114, 114a, 114b). Metal complexes having a quinoline ring or a benzoquinoline ring such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq3), Almq3, 8-quinolinolato-lithium (abbreviation: Liq), BeBq2, bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), etc.; metal complexes having an oxazole ring or a thiazole ring such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), etc.

[0231] In addition, polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) can also be used as the electron transporting material.

[0232] Further, the electron transport layer (114, 114a, 114b) may have not only a single layer structure but also a structure in which two or more layers made of the above substances are laminated.

[0233] 〈Electron injection layer〉 The electron injection layers (115, 115a, 115b) are layers containing a material with high electron injection properties. Also, the electron injection layers (115, 115a, 115b) are layers for enhancing the electron injection efficiency from the second electrode 102. When comparing the work function value of the material used for the second electrode 102 with the LUMO level value of the material used for the electron injection layers (115, 115a, 115b), it is preferable to use a material with a small difference (0.50 eV or less). Therefore, for the electron injection layer 115, lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-hydroxyquinolinato-lithium (abbreviation: Liq), 2-(2-pyridyl)phenolato-lithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolato-lithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolato-lithium (abbreviation: LiPPP), lithium oxide (LiO x) Alkali metals, alkaline earth metals, or their compounds such as cesium carbonate can be used. Also, rare earth metal compounds such as erbium fluoride (ErF3) and ytterbium (Yb) can be used. Further, compounds having a 1,3,4,6,7,8-tetrahydro-2H-pyrimido[1,2-a]pyrimidine skeleton such as 1-(9,9'-spirobi[9H-fluorene]-2-yl)-1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (abbreviation: 2hppSF), 1,1'-(9,9'-spirobi[9H-fluorene]-2,7-diyl)bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) (abbreviation: 2,7hpp2SF), 1,1'-pyridine-2,6-diyl-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) (abbreviation: hpp2Py), etc. can also be used. Note that the electron injection layer (115, 115a, 115b) may be formed by mixing a plurality of the above materials, or may be formed by laminating a plurality of the above materials. Also, electrides may be used in the electron injection layer (115, 115a, 115b). Examples of electrides include substances obtained by adding electrons at a high concentration to a mixed oxide of calcium and aluminum. Note that the substances constituting the above-described electron transport layer (114, 114a, 114b) can also be used.

[0234] In addition, a mixed material formed by mixing an organic compound and an electron donor may be used for the electron injection layer (115, 115a, 115b). Since electrons are generated in the organic compound by the electron donor in such a mixed material, it is excellent in electron injection property and electron transport property. In this case, the organic compound is preferably a material excellent in transporting the generated electrons. Specifically, for example, an electron transporting material (such as a metal complex and a heteroaromatic compound) used for the above-described electron transport layer (114, 114a, 114b) can be used. As the electron donor, any substance that exhibits electron donating property with respect to the organic compound may be used. Specifically, an alkali metal, an alkaline earth metal, and a rare earth metal are preferable, and examples thereof include lithium, cesium, magnesium, calcium, erbium, ytterbium, and the like. In addition, an alkali metal oxide and an alkaline earth metal oxide are preferable, and examples thereof include lithium oxide, calcium oxide, barium oxide, and the like. Further, a Lewis base such as magnesium oxide can also be used. Further, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can also be used. Further, a plurality of these materials may be laminated and used.

[0235] In addition, a mixed material formed by mixing an organic compound and a metal may be used for the electron injection layer (115, 115a, 115b). Here, the organic compound used preferably has a LUMO level of -3.60 eV or more and -2.30 eV or less. Further, a material having a lone pair of electrons is preferable.

[0236] Therefore, as the organic compound used in the above-mentioned mixed material, a mixed material formed by mixing a heteroaromatic compound, which has been described above as being usable for an electron transport layer, with a metal may be used. As the heteroaromatic compound, a heteroaromatic compound having a 5-membered ring structure (such as an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, a benzimidazole ring, etc.), a heteroaromatic compound having a 6-membered ring structure (such as a pyridine ring, a diazine ring (including a pyrimidine ring, a pyrazine ring, a pyridazine ring, etc.), a triazine ring, a bipyridine ring, a terpyridine ring, etc.), a heteroaromatic compound having a condensed ring structure (such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a phenanthroline ring, etc.) containing a 6-membered ring structure in part, and other materials having non-bonding electrons are preferable. Since specific materials have been described above, the description here is omitted.

[0237] Further, as the metal used in the above-mentioned mixed material, it is preferable to use a transition metal belonging to Group 5, Group 7, Group 9 or Group 11 in the periodic table and a material belonging to Group 13. For example, Ag, Cu, Al, or In, etc. may be mentioned. Also, at this time, the organic compound forms a singly occupied molecular orbital (SOMO) with the transition metal.

[0238] In addition, for example, when amplifying the light obtained from the light-emitting layer 113b, it is preferable that the optical distance between the second electrode 102 and the light-emitting layer 113b is less than 1 / 4 of the wavelength λ of the light exhibited by the light-emitting layer 113b. In this case, adjustment can be made by changing the film thickness of the electron transport layer 114b or the electron injection layer 115b.

[0239] Also, as in the light-emitting device shown in FIG. 4(F), by providing a charge generation layer 106 between two organic compound layers (103a, 103b), a structure in which a plurality of organic compound layers are laminated between a pair of electrodes (also referred to as a tandem structure) can also be formed.

[0240] 〈Charge Generation Layer〉 When a voltage is applied between the first electrode (anode) 101 and the second electrode (cathode) 102, the charge generation layer 106 has a function of injecting electrons into the organic compound layer 103a and injecting holes into the organic compound layer 103b. Note that the charge generation layer 106 may be a structure in which an electron acceptor is added to a hole-transporting material (also referred to as a P-type layer), or a structure in which an electron donor is added to an electron-transporting material (also referred to as an electron injection buffer layer). Further, both of these structures may be laminated. Furthermore, 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 above-described materials, it is possible to suppress an increase in the driving voltage when the organic compound layers are laminated.

[0241] In the charge generation layer 106, when a structure (P-type layer) is adopted in which an electron acceptor is added to a hole-transporting material that is an organic compound, the hole-transporting materials shown in this embodiment can be used. Examples of the electron acceptor include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, etc. Oxides of metals belonging to Groups 4 to 8 in the periodic table of elements can also be mentioned. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, etc. can be mentioned. Note that the above-described acceptor materials may be used. Further, it may be used as a mixed film formed by mixing the materials constituting the P-type layer, or single films containing the respective materials may be laminated.

[0242] In addition, in the charge generation layer 106, when the structure is such that an electron donor is added to the electron transporting material (electron injection buffer layer), as the electron transporting material, the materials shown in this embodiment can be used. As the electron donor, an alkali metal, an alkaline earth metal, a rare earth metal, a metal belonging to Group 2 or Group 13 in the periodic table, and their oxides and carbonates can be used. Specifically, it is preferable to use lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide (Li2O), cesium carbonate, etc. Also, a compound of an alkali metal such as Liq may be used. Further, an organic compound such as tetrathianaphthacene may be used as the electron donor. Also, organic compounds having a 1,3,4,6,7,8-tetrahydro-2H-pyrimido[1,2-a]pyrimidine skeleton such as 2hppSF, 2,7hpp2SF, hpp2Py, etc. may be used as the electron donor. When these organic compounds are used as the electron donor, as the electron transporting material to be combined, an organic compound containing a heteroaromatic ring having a phenanthroline ring such as bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), etc. is preferably used because the driving voltage of the light emitting device can be reduced.

[0243] When an electron relay layer is provided between the P-type layer and the electron injection buffer layer in the charge generation layer 106, the electron relay layer contains at least a substance having electron transport properties and has a function of preventing the interaction between the electron injection buffer layer and the P-type layer and smoothly transferring electrons. The LUMO level of the substance having electron transport properties contained in the electron relay layer is preferably between the LUMO level of the acceptor substance in the P-type layer and the LUMO level of the substance having electron transport properties contained in the electron transport layer in contact with the charge generation layer 106. The specific energy level of the LUMO level in the substance having electron transport properties used for the electron relay layer is preferably -5.00 eV or more, preferably -5.00 eV or more and -3.00 eV or less. In addition, as the substance having electron transport properties used for the electron relay layer, it is preferable to use a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0244] In addition, from the viewpoint of light extraction efficiency, the charge generation layer 106 preferably has translucency with respect to visible light (specifically, the transmittance of visible light with respect to the charge generation layer 106 is 40% or more). Further, the charge generation layer 106 can function even with a lower conductivity than the first electrode 101 and the second electrode 102.

[0245] In FIG. 4(F), a configuration in which two organic compound layers 103 are laminated is shown. However, a laminated structure of three or more organic compound layers may be used by providing a charge generation layer between different organic compound layers.

[0246] <Cap Layer> Although not shown in FIGS. 4(A) to 4(F), a cap layer may be provided on the second electrode 102 of the light-emitting device. For the cap layer, for example, a material having a high refractive index can be used. By providing the cap layer on the second electrode 102, the light extraction efficiency of the light emitted from the second electrode 102 can be improved.

[0247] Specific examples of materials that can be used for the cap layer include 5,5'-diphenyl-2,2'-di-5H-[1]benzothieno[3,2-c]carbazole (abbreviation: BisBTc), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), and the like.

[0248] 〈Substrate〉 The light-emitting device shown in this embodiment can be formed on various substrates. Note that the type of the substrate is not limited to a specific one. As an example of the substrate, a semiconductor substrate (for example, a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate having a stainless steel foil, a tungsten substrate, a substrate having a tungsten foil, a flexible substrate, a laminated film, paper containing a fibrous material, or a base film can be mentioned.

[0249] As an example of the glass substrate, barium borosilicate glass, aluminoborosilicate glass, or soda lime glass can be mentioned. Further, as an example of the flexible substrate, the laminated film, the base film, etc., plastics typified by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES), synthetic resins such as acrylic resins, polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride, polyamide, polyimide, aramid, epoxy resin, an inorganic vapor deposition film, or papers can be mentioned.

[0250] In the fabrication of the light-emitting device described in this embodiment, vapor-phase methods such as vapor deposition, liquid-phase methods such as spin coating and inkjet printing can be used. When using the vapor deposition method, physical vapor deposition methods (PVD methods) such as sputtering, ion plating, ion beam vapor deposition, molecular beam epitaxy, and vacuum vapor deposition, chemical vapor deposition (CVD) methods, etc. can be used. In particular, for the layers having various functions included in the organic compound layer of the light-emitting device (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, electron injection layer 115), vapor deposition methods (such as vacuum vapor deposition), coating methods (dip coating, die coating, bar coating, spin coating, spray coating, etc.), printing methods (inkjet printing, screen (stencil printing) method, offset (lithography) method, flexo (letterpress printing) method, gravure method, microcontact method, etc.) can be used to form them.

[0251] In addition, when applying film-forming methods such as the above coating method and printing method, high molecular compounds (oligomers, dendrimers, polymers, etc.), medium molecular compounds (compounds in the intermediate region between low molecules and high molecules: molecular weight 400 or more and 4000 or less), inorganic compounds (quantum dot materials, etc.) can be used. As quantum dot materials, colloidal quantum dot materials, alloy-type quantum dot materials, core-shell type quantum dot materials, core-type quantum dot materials, etc. can be used.

[0252] Each layer (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, electron injection layer 115) constituting the organic compound layer 103 of the light-emitting device shown in this embodiment is not limited to the materials shown in this embodiment, and other materials can be used in combination as long as they can satisfy the functions of each layer.

[0253] As described above, the configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

[0254] (Embodiment 3) As illustrated in FIGS. 5(A) and 5(B), a plurality of light-emitting devices 130 are formed on an insulating layer 171 and constitute a display device. In the present embodiment, a display device according to an aspect of the present invention will be described in detail.

[0255] The light-emitting device 1000 has a pixel portion 177 in which a plurality of pixels 178 are arranged in a matrix. The pixel 178 has a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0256] In this specification and the like, for example, when describing matters common to the sub-pixel 110R, the sub-pixel 110G, and the sub-pixel 110B, they may be described by referring to them as the sub-pixel 110. For other components distinguished by alphabets, when describing matters common to them, they may be described using symbols with the alphabets omitted.

[0257] The sub-pixel 110R exhibits red light, the sub-pixel 110G exhibits green light, and the sub-pixel 110B exhibits blue light. Thereby, an image can be displayed on the pixel portion 177. In the present embodiment, three-color sub-pixels of red (R), green (G), and blue (B) are described as an example, but combinations of sub-pixels of other colors may also be used. Also, the number of sub-pixels is not limited to three and may be four or more. Examples of four sub-pixels include four-color sub-pixels of R, G, B, and white (W), four-color sub-pixels of R, G, B, and Y, and four sub-pixels of R, G, B, and infrared light (IR).

[0258] In this specification and the like, the row direction may be referred to as the X direction and the column direction may be referred to as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly.

[0259] FIG. 5(A) shows an example in which sub-pixels of different colors are arranged side by side in the X direction and sub-pixels of the same color are arranged side by side in the Y direction. Note that sub-pixels of different colors may be arranged side by side in the Y direction and sub-pixels of the same color may be arranged side by side in the X direction.

[0260] Outside the pixel portion 177, a connection portion 140 may be provided, and a region 141 may be provided. The region 141 is provided between the pixel portion 177 and the connection portion 140. An organic compound layer 103 is provided in the region 141. Further, a conductive layer 151C is provided in the connection portion 140.

[0261] In FIG. 5, an example is shown in which the region 141 and the connection portion 140 are located on the right side of the pixel portion 177, but the positions of the region 141 and the connection portion 140 are not particularly limited. Further, the region 141 and the connection portion 140 may be singular or plural.

[0262] FIG. 5(B) is an example of a cross-sectional view between the dashed-dotted line A1 - A2 in FIG. 5(A). As shown in FIG. 5(B), the light-emitting device 1000 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). Openings reaching the conductive layer 172 are provided in the insulating layer 175, the insulating layer 174, and the insulating layer 173, and plugs 176 are provided so as to fill the openings.

[0263] In the pixel portion 177, a light-emitting device 130 is provided on the insulating layer 175 and the plug 176. Further, a protective layer 135 is provided so as to cover the light-emitting device 130. A substrate 120 is bonded by a resin layer 122 on the protective layer 135. Further, it is preferable that an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are provided between adjacent light-emitting devices 130.

[0264] In FIG. 5(B), a plurality of cross-sections of the inorganic insulating layer 125 and the insulating layer 127 are shown, but when the light-emitting device 1000 is viewed from above, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are each connected into one. That is, the insulating layer 127 is preferably an insulating layer having an opening on the first electrode.

[0265] In FIG. 5(B), light-emitting devices 130R, 130G, and 130B are shown as the light-emitting device 130. The light-emitting devices 130R, 130G, and 130B shall emit light of different colors from each other. For example, the light-emitting device 130R can emit red light, the light-emitting device 130G can emit green light, and the light-emitting device 130B can emit blue light. Further, the light-emitting device 130R, 130G, or 130B may emit other visible light or infrared light.

[0266] The display device according to one aspect of the present invention can be a top emission type that emits light in a direction opposite to the substrate on which the light-emitting device is formed, for example. Note that the display device according to one aspect of the present invention may be a bottom emission type.

[0267] Examples of the light-emitting substance included in the light-emitting device 130 include organic compounds or organometallic complexes such as substances that emit fluorescence (fluorescent materials), substances that emit phosphorescence (phosphorescent materials), and substances that exhibit thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) materials). Inorganic compounds such as quantum dots may also be used.

[0268] The light-emitting device 130R has a configuration as shown in Embodiment 1. It includes a first electrode (pixel electrode) composed 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. Note that the common layer 104 may or may not be provided, but it is preferable to provide it because it can reduce damage to the organic compound layer 103R during processing. When the common layer 104 is provided, the common layer 104 is preferably an electron injection layer. Also, when the common layer 104 is not provided, the organic compound layer 103R corresponds to the organic compound layer 103 in Embodiment 1 and Embodiment 2. When 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 and Embodiment 2.

[0269] The light-emitting device 130G has a configuration as shown in Embodiment 1. It includes a first electrode (pixel electrode) composed 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. Note that the common layer 104 may or may not be provided, but it is preferable to provide it because it can reduce damage to the organic compound layer 103G during processing. Also, when the common layer 104 is not provided, the organic compound layer 103G corresponds to the organic compound layer 103 in Embodiment 1 and Embodiment 2. When 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 and Embodiment 2.

[0270] The light-emitting device 130B has the configuration as shown in Embodiment 1. It has a first electrode (pixel electrode) composed 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. Note that the common layer 104 may or may not be provided, but it is preferable to provide it because it can reduce damage to the organic compound layer 103B during processing. Also, when the common layer 104 is not provided, the organic compound layer 103B corresponds to the organic compound layer 103 in Embodiment 1 and Embodiment 2. When 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 and Embodiment 2.

[0271] Of the pixel electrode and the common electrode of the light-emitting device, one functions as an anode and the other functions as a cathode. Hereinafter, unless otherwise specified, it will be described assuming that the pixel electrode functions as an anode and the common electrode functions as a cathode.

[0272] The organic compound layers 103R, 103G, and 103B are independent in an island shape for each light-emitting device or for each emission color. By providing the organic compound layer 103 in an island shape for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in a high-definition display device. Thereby, crosstalk can be prevented, and a display device with extremely high contrast can be realized. In particular, a display device with high current efficiency at low luminance can be realized.

[0273] The island-shaped organic compound layer 103 is formed by forming an EL film and processing the EL film using a lithography method.

[0274] In addition, in the display device according to one aspect of the present invention, it is preferable that the first electrode (pixel electrode) of the light-emitting device has a stacked structure. For example, in the example shown in FIG. 5(B), the first electrode of the light-emitting device 130 has a stacked structure of a conductive layer 151 and a conductive layer 152. For example, when the light-emitting device 1000 is a top emission type and the pixel electrode of the light-emitting device 130 functions as an anode, the conductive layer 151 is preferably a layer having a high reflectance for visible light, and the conductive layer 152 is preferably a layer having, for example, visible light transmittance and a large work function. When the light-emitting device 1000 is a top emission type, the higher the reflectance of the pixel electrode for visible light, the higher the light extraction efficiency of the light emitted from the organic compound layer 103 can be. Further, when the pixel electrode functions as an anode, the larger the work function of the pixel electrode, the easier the injection of holes into the organic compound layer 103 becomes. From the above, by forming the pixel electrode of the light-emitting device 130 into a stacked structure of a conductive layer 151 having a high reflectance for visible light and a conductive layer 152 having a large work function, the light-emitting device 130 can be made a light-emitting device having high light extraction efficiency and a low driving voltage.

[0275] When the conductive layer 151 is a layer having a high reflectance for visible light, the reflectance of the conductive layer 151 for visible light is preferably, for example, 40% or more and 100% or less, or 70% or more and 100% or less. Further, when the conductive layer 152 is an electrode having visible light transmittance, the transmittance for visible light is preferably, for example, 40% or more.

[0276] Here, when the pixel electrode has a stacked structure composed of a plurality of layers, for example, the pixel electrode may be deteriorated due to the reaction between the plurality of layers. For example, when the film formed after the formation of the pixel electrode is removed by a wet etching method, galvanic corrosion may occur due to the chemical solution coming into contact with the pixel electrode.

[0277] Therefore, in the light-emitting device 1000 of the present embodiment, an insulating layer 156 is formed on the side surfaces of the conductive layer 151 and the conductive layer 152. Thereby, even when removing a film formed after forming a pixel electrode having, for example, the conductive layer 151 and the conductive layer 152 by a wet etching method, it is possible to suppress the chemical solution from contacting the conductive layer 151. Therefore, for example, the occurrence of galvanic corrosion on the pixel electrode can be suppressed. Therefore, since the light-emitting device 1000 can be manufactured by a method with a high yield, it can be made into a low-cost display device. Further, since the occurrence of defects in the light-emitting device 1000 can be suppressed, the light-emitting device 1000 can be made into a highly reliable display device.

[0278] As the conductive layer 151, for example, a metal material can be used. Specifically, for example, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), etc., and alloys containing these appropriately combined can also be used.

[0279] As the conductive layer 152, an oxide having any one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, 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, etc., any one or more of these conductive oxides are preferably used. In particular, indium tin oxide containing silicon has a large work function, for example, the work function is 4.0 eV or more, so it can be suitably used as the conductive layer 152.

[0280] The conductive layer 151 may have a laminated structure of a plurality of layers having different materials, and the conductive layer 152 may have a laminated structure of a plurality of layers having different materials. In this case, the conductive layer 151 may have a layer using a material that can be used for the conductive layer 152 such as a conductive oxide, and the conductive layer 152 may have a layer using a material that can be used for the conductive layer 151 such as a metal material. For example, when the conductive layer 151 has a laminated structure of two or more layers, the layer in contact with the conductive layer 152 can be a layer using a material that can be used for the conductive layer 152.

[0281] Note that the end of the insulating layer 156 may have a tapered shape. Specifically, by having the end of the insulating layer 156 have a tapered shape with a taper angle of less than 90°, the covering property of the structure provided along the side surface of the insulating layer 156 can be enhanced.

[0282] FIG. 6(A) shows a diagram in the case where the conductive layer 151 has a laminated structure of a plurality of layers containing different materials. As shown in FIG. 6(A), the conductive layer 151 has a configuration including a conductive layer 151a, a conductive layer 151b on the conductive layer 151a, and a conductive layer 151c on the conductive layer 151b. That is, the conductive layer 151 shown in FIG. 6(A) has a three-layer laminated structure. Thus, when the conductive layer 151 has a laminated structure of a plurality of layers, the reflectance of at least one layer among the layers constituting the conductive layer 151 with respect to visible light may be made higher than the reflectance of the conductive layer 152 with respect to visible light.

[0283] In the example shown in FIG. 6(A), the conductive layer 151b is configured to be sandwiched between the conductive layer 151a and the conductive layer 151c. It is preferable to use a material that is less likely to deteriorate than the conductive layer 151b for the conductive layer 151a and the conductive layer 151c. For example, for the conductive layer 151a, a material can be used for which the occurrence of migration due to contact with the insulating layer 175 is less likely to occur than in the conductive layer 151b. Also, for the conductive layer 151c, a material can be used that is less likely to oxidize than the conductive layer 151b and for which the electrical resistivity of the oxide is lower than that of the oxide of the material used for the conductive layer 151b.

[0284] As described above, by configuring the conductive layer 151b to be sandwiched between the conductive layer 151a and the conductive layer 151c, the range of material selection for the conductive layer 151b can be widened. As a result, for example, the conductive layer 151b can be a layer having a higher reflectance for visible light than at least one of the conductive layer 151a and the conductive layer 151c. For example, aluminum can be used as the conductive layer 151b. Note that an alloy containing aluminum may be used for the conductive layer 151b. Further, as the conductive layer 151a, titanium, which has a lower reflectance for visible light compared to aluminum but is less likely to cause migration than aluminum even when in contact with the insulating layer 175, can be used. Furthermore, as the conductive layer 151c, titanium, which has a lower reflectance for visible light compared to aluminum but is less likely to be oxidized than aluminum and has an electrical resistivity of the oxide lower than that of aluminum oxide, can be used.

[0285] In addition, silver or an alloy containing silver may be used as the conductive layer 151c. Silver has the property of having a higher reflectance for visible light than titanium. Furthermore, silver has the property of being less likely to be oxidized than aluminum and the electrical resistivity of silver oxide is lower than that of aluminum oxide. As described above, when silver or an alloy containing silver is used as the conductive layer 151c, the reflectance of the conductive layer 151 for visible light can be suitably increased while suppressing an increase in the electrical resistance of the pixel electrode due to oxidation of the conductive layer 151b. Here, as the alloy containing silver, for example, an alloy of silver, palladium, and copper (also denoted as Ag-Pd-Cu, APC) can be applied. Note that when silver or an alloy containing silver is used as the conductive layer 151c and aluminum is used as the conductive layer 151b, the reflectance of the conductive layer 151c for visible light can be made higher than the reflectance of the conductive layer 151b for visible light. Here, silver or an alloy containing silver may be used as the conductive layer 151b. Also, silver or an alloy containing silver may be used as the conductive layer 151a.

[0286] On the one hand, the film using titanium is superior in processability by etching to the film using silver. Therefore, by using titanium as the conductive layer 151c, the conductive layer 151c can be easily formed. Note that the film using aluminum is also superior in processability by etching to the film using silver.

[0287] As described above, by forming the conductive layer 151 into a laminated structure of a plurality of layers, the characteristics of the display device can be improved. For example, the light-emitting device 1000 can be made into a display device with high light extraction efficiency and high reliability.

[0288] Here, when a microcavity structure is applied to the light-emitting device 130, if silver, which is a material with a high reflectance for visible light, or an alloy containing silver is used as the conductive layer 151c, the light extraction efficiency of the light-emitting device 1000 can be suitably increased.

[0289] As described above, it is preferable that the side surface of the conductive layer 151 has a tapered shape. Specifically, it is preferable that the side surface of the conductive layer 151 has a tapered shape with a taper angle of less than 90°. For example, in the conductive layer 151 having the configuration shown in FIG. 6(A), it is preferable that at least one side surface of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c has a tapered shape.

[0290] The conductive layer 151 shown in FIG. 6(A) can be formed using a lithography method. Specifically, first, a conductive film to be the conductive layer 151a, a conductive film to be the conductive layer 151b, and a conductive film to be the conductive layer 151c are sequentially formed. Next, a resist mask is formed on the conductive film to be the conductive layer 151c. Then, the conductive film in the region that does not overlap with the resist mask is removed using, for example, an etching method. Here, by processing the conductive film under conditions where the resist mask is likely to recede (shrink) as compared with the case where the conductive layer 151 is formed so that the side surface does not have a tapered shape, that is, the side surface is perpendicular, the side surface of the conductive layer 151 can be made into a tapered shape.

[0291] Here, when the conductive film is processed under conditions where the resist mask is likely to recede (shrink), the conductive film may be more likely to be processed in the horizontal direction. That is, the isotropic property of etching may be higher than when forming the conductive layer 151 such that the side surface is perpendicular.

[0292] Also, when the conductive layer 151 has a laminated structure of a plurality of layers made of different materials, the ease of horizontal processing may be different between the plurality of layers. For example, the ease of horizontal processing may be different between the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c.

[0293] In this case, after processing the conductive film, as shown in FIG. 6(A), the side surface of the conductive layer 151b may be located inside the side surfaces of the conductive layer 151a and the conductive layer 151c, and a protruding portion may be formed. As a result, the covering property of the conductive layer 152 with respect to the conductive layer 151 may be reduced, and there is a risk of step breakage of the conductive layer 152.

[0294] Therefore, it is preferable to provide the insulating layer 156 as shown in FIG. 6(A). FIG. 6(A) shows an example in which the insulating layer 156 is provided on the conductive layer 151a so as to have a region overlapping the side surface of the conductive layer 151b. Thereby, the occurrence of step breakage or thinning of the conductive layer 152 due to the protruding portion can be suppressed, and thus connection failure or an increase in driving voltage can be suppressed.

[0295] Note that in FIG. 6(A), a structure in which the side surface of the conductive layer 151b is entirely covered by the insulating layer 156 is illustrated, but a part of the side surface of the conductive layer 151b may not be covered by the insulating layer 156. Similarly, in the pixel electrode having the configuration shown hereinafter, a part of the side surface of the conductive layer 151b may not be covered by the insulating layer 156.

[0296] When the conductive layer 151 has the structure shown in FIG. 6(A), the conductive layer 152 covers the conductive layer 151a, the conductive layer 151b, the conductive layer 151c, and the insulating layer 156, and is provided so as to be electrically connected to the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c. Thereby, even when, for example, a film formed after the formation of the conductive layer 152 is removed by a wet etching method, the chemical solution can be prevented from coming into contact with any of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c. Therefore, the occurrence of corrosion can be suppressed in any of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c. Therefore, the light-emitting device 1000 can be manufactured by a method with a high yield. In addition, the occurrence of defects can be suppressed, and the light-emitting device 1000 can be a highly reliable display device.

[0297] Here, as shown in FIG. 6(A), the insulating layer 156 preferably has a curved surface. Thereby, for example, the occurrence of steps in the conductive layer 152 covering the insulating layer 156 can be suppressed as compared with the case where the side surface of the insulating layer 156 is perpendicular (parallel to the Z direction). Further, even when the insulating layer 156 has a tapered shape on the side surface, specifically, a tapered shape with a taper angle of less than 90°, the occurrence of steps in the conductive layer 152 covering the insulating layer 156 can be suppressed as compared with the case where the side surface of the insulating layer 156 is perpendicular. From the above, the light-emitting device 1000 can be manufactured by a method with a high yield. In addition, the occurrence of defects can be suppressed, and the light-emitting device 1000 can be a highly reliable display device.

[0298] Note that in FIG. 6(A), a configuration is shown in which the side surface of the conductive layer 151b is located inside the side surfaces of the conductive layer 151a and the conductive layer 151c, but one aspect of the present invention is not limited to this. For example, the side surface of the conductive layer 151b may be located outside the side surface of the conductive layer 151a. Also, the side surface of the conductive layer 151b may be located outside the side surface of the conductive layer 151c.

[0299] Figures 6(B) to 6(D) show other configurations of the first electrode 101. Figure 6(B) shows a configuration in which, in the first electrode 101 of Figure 6(A), the insulating layer 156 covers not only the side surface of the conductive layer 151b but also the side surfaces of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c.

[0300] Figure 6(C) shows a configuration in which the insulating layer 156 is not provided in the first electrode 101 of Figure 6(A).

[0301] Figure 6(D) shows a configuration in which, in the first electrode 101 of Figure 6(A), the conductive layer 151 does not have a stacked structure and the conductive layer 152 has a stacked structure.

[0302] The conductive layer 152a is a layer having, for example, higher adhesion to the conductive layer 152b than the insulating layer 175. As the conductive layer 152a, for example, an oxide containing any one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, it is preferable to use a conductive oxide containing any one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium titanium oxide, zinc titanate, aluminum zinc oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. Thus, peeling of the conductive layer 152b can be suppressed. Also, the conductive layer 152b can be configured not to be in contact with the insulating layer 175.

[0303] The conductive layer 152b is a layer with a higher reflectance for visible light (for example, the reflectance for light with a predetermined wavelength within the range of 400 nm or more and less than 750 nm) than the conductive layer 151, the conductive layer 152a, and the conductive layer 152c. The reflectance of the conductive layer 152b for visible light can be, for example, 70% or more and 100% or less, preferably 80% or more and 100% or less, and more preferably 90% or more and 100% or less. Also, as the conductive layer 152b, a material with a higher reflectance for visible light than aluminum, for example, can be used. Specifically, as the conductive layer 152b, silver or an alloy containing silver can be used, for example. Examples of the alloy containing silver include an alloy of silver, palladium, and copper (APC). As described above, the light-emitting device 1000 can be made into a light-emitting device with high light extraction efficiency. Note that a metal other than silver may be used as the conductive layer 152b.

[0304] When the conductive layer 151 and the conductive layer 152 function as anodes, the conductive layer 152c is preferably a layer with a large work function. The conductive layer 152c is, for example, a layer with a larger work function than the conductive layer 152b. As the conductive layer 152c, the same material as the material that can be used for the conductive layer 152a can be used, for example. For example, a configuration can be adopted in which the same type of material is used for the conductive layer 152a and the conductive layer 152c. For example, when indium tin oxide is used for the conductive layer 152a, indium tin oxide can also be used for the conductive layer 152c.

[0305] Note that when the conductive layer 151 and the conductive layer 152 function as cathodes, it is preferable that they are layers with a small work function. The conductive layer 152c is, for example, a layer with a smaller work function than the conductive layer 152b.

[0306] Further, the conductive layer 152c is preferably a layer having a high transmittance to visible light (for example, the transmittance to light of a predetermined wavelength within the range of 400 nm or more and less than 750 nm). For example, the transmittance of the conductive layer 152c to visible light is preferably higher than the transmittance of the conductive layer 151 and the conductive layer 152b to visible light. For example, the transmittance of the conductive layer 152c to visible light can be 60% or more and 100% or less, preferably 70% or more and 100% or less, and more preferably 80% or more and 100% or less. As described above, among the light emitted from the organic compound layer 103, the light absorbed by the conductive layer 152c can be reduced. Further, as described above, the conductive layer 152b under the conductive layer 152c can be a layer having a high reflectance to visible light. Therefore, the light-emitting device 1000 can be a display device having high light extraction efficiency.

[0307] Next, an example of a method for manufacturing the light-emitting device 1000 having the configuration shown in FIG. 5(A) will be described with reference to FIGS. 10 to 18. The light-emitting device included in the light-emitting device 1000 has an organic layer formed by a manufacturing process including a treatment using water. By applying the light-emitting device of one aspect of the present invention as the light-emitting device included in the display device of one aspect of the present invention, it is possible to provide a display device having a light-emitting device with a reduced driving voltage and high luminous efficiency.

[0308] [Example of manufacturing method] The thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an ALD method, or the like. Examples of the CVD method include a plasma enhanced CVD (PECVD) method and a thermal CVD method. Further, one of the thermal CVD methods is a metal organic CVD (MOCVD) method.

[0309] In addition, thin films (such as insulating films, semiconductor films, and conductive films) that make up the display device can be formed by wet film-forming methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor blade method, slit coating, roll coating, curtain coating, or knife coating.

[0310] In particular, for the fabrication of light-emitting devices, vacuum processes such as vapor deposition methods and solution processes such as spin coating methods and inkjet methods can be used. Examples of vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam evaporation, molecular beam epitaxy, and vacuum evaporation, and chemical vapor deposition (CVD) methods. In particular, for functional layers (such as hole injection layers, hole transport layers, hole blocking layers, light-emitting layers, electron blocking layers, electron transport layers, and electron injection layers) included in organic compound layers, they can be formed by methods such as vapor deposition (such as vacuum evaporation), coating methods (such as dip coating, die coating, bar coating, spin coating, spray coating), and printing methods (such as inkjet, screen (stencil printing), offset (lithography), flexo (letterpress), gravure, or microcontact printing).

[0311] When processing the thin films that make up the display device, for example, it can be processed using a lithography method. Or, the thin films may be processed by a nanoimprint method, a sandblasting method, a lift-off method, etc. Also, island-shaped thin films may be directly formed by a film-forming method using a shielding mask such as a metal mask.

[0312] As the lithography method, for example, a photolithography method can be used. There are typically two representative methods for the photolithography method. One is a method in which a resist mask is formed on the thin film to be processed, and the thin film is processed by, for example, etching, and then the resist mask is removed. The other is a method in which after forming a photosensitive thin film, exposure and development are performed to process the thin film into a desired shape.

[0313] In the photolithography method, as the light used for exposure, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or light obtained by mixing these can be used. In addition, ultraviolet light, KrF laser light, ArF laser light, etc. can also be used. Further, exposure may be performed by immersion lithography technology. Also, as the light used for exposure, extreme ultraviolet (EUV) light or X-rays may be used. Further, instead of the light used for exposure, an electron beam can also be used. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because extremely fine processing becomes possible. Note that when performing exposure by scanning a beam such as an electron beam, a photomask is not required.

[0314] For etching the thin film, a dry etching method, a wet etching method, a sandblasting method, or the like can be used.

[0315] First, as shown in FIG. 7(A), an insulating layer 171 is formed on a substrate (not shown). Subsequently, a conductive layer 172 and a conductive layer 179 are formed on the insulating layer 171, and an insulating layer 173 is formed on the insulating layer 171 so as to cover the conductive layer 172 and the conductive layer 179. Subsequently, an insulating layer 174 is formed on the insulating layer 173, and an insulating layer 175 is formed on the insulating layer 174.

[0316] As the substrate, a substrate having heat resistance sufficient to withstand at least subsequent heat treatment can be used. When an insulating substrate is used as the substrate, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, an organic resin substrate, or the like can be used. Further, a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, or a semiconductor substrate such as an SOI substrate can be used.

[0317] Subsequently, as shown in FIG. 7(A), an opening reaching the conductive layer 172 is formed in the insulating layer 175, the insulating layer 174, and the insulating layer 173. Subsequently, a plug 176 is formed so as to fill the opening.

[0318] Subsequently, as shown in FIG. 7(A), a conductive film 151f, which will later become the conductive layers 151R, 151G, 151B, and 151C, is formed on the plug 176 and on the insulating layer 175. For forming the conductive film 151f, for example, a sputtering method or a vacuum evaporation method can be used. Also, as the conductive film 151f, for example, a metal material can be used.

[0319] Subsequently, as shown in FIG. 7(A), a conductive film 152f, which will later become the conductive layers 152R, 152G, 152B, and 152C, is formed on the conductive film 151f. For forming the conductive film 152f, for example, a sputtering method or a vacuum evaporation method can be used. Also, as the conductive film 152f, for example, a conductive oxide can be used. Or, a laminated structure of a film using a metal material and a film using a conductive oxide on the said film can be applied as the conductive film 152f. For example, a laminated structure of a film using titanium, silver, or an alloy containing silver and a film using a conductive oxide on the said film can be applied as the conductive film 152f.

[0320] Also, for forming the conductive film 152f, an ALD method can be used. In this case, as the conductive film 152f, an oxide having any one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. In this case, the introduction of a precursor (generally sometimes called a precursor, a metal precursor, etc.), the purge of the said precursor, the introduction of an oxidizing agent (generally sometimes called a reactant, a reactant, or a non-metal precursor, etc.), and the purge of the said oxidizing agent are regarded as one cycle, and by repeating the said cycle, the conductive film 152f can be formed. Here, when forming an oxide film containing a plurality of metals such as indium tin oxide as the conductive film 152f, the composition of the metal can be controlled by varying the number of cycles for each type of precursor.

[0321] For example, when forming an indium tin oxide film as the conductive film 152f, after introducing a precursor containing indium, the precursor is purged and an oxidizing agent is introduced to form an In-O film. Next, after introducing a precursor containing tin, the precursor is purged and an oxidizing agent is introduced to form a Sn-O film. Here, by making the number of cycles of forming the In-O film larger than the number of cycles of forming the Sn-O film, the number of indium atoms contained in the conductive film 152f can be made larger than the number of tin atoms.

[0322] Also, for example, when forming a zinc oxide film as the conductive film 152f, a Zn-O film is formed by the above procedure. Also, for example, when forming an aluminum zinc oxide film as the conductive film 152f, a Zn-O film and an Al-O film are each formed by the above procedure. Also, for example, when forming a titanium oxide film as the conductive film 152f, a Ti-O film is formed by the above procedure. Also, for example, when forming an indium tin oxide film containing silicon as the conductive film 152f, an In-O film, a Sn-O film, and a Si-O film are formed by the above procedure. Also, for example, when forming a zinc oxide film containing gallium, a Ga-O film and a Zn-O film are formed by the above procedure.

[0323] As precursors containing indium, for example, triethylindium, trimethylindium, or [1,1,1-trimethyl-N-(trimethylsilyl)amide]-indium can be used. As precursors containing tin, for example, tin chloride, or tetrakis(dimethylamide)tin can be used. As precursors containing zinc, for example, diethylzinc, or dimethylzinc can be used. As precursors containing gallium, for example, triethylgallium can be used. As precursors containing titanium, for example, titanium chloride, tetrakis(dimethylamide)titanium, or tetraisopropyl titanate can be used. As precursors containing aluminum, for example, aluminum chloride, or trimethylaluminum can be used. As precursors containing silicon, trisilylamine, bis(diethylamino)silane, tris(dimethylamino)silane, bis(tert-butylamino)silane, or bis(ethylmethylamino)silane can be used. Further, as the oxidizing agent, water vapor, oxygen plasma, or ozone gas can be used.

[0324] Subsequently, as shown in FIG. 7(A), a resist mask 191 is formed on the conductive film 151f and the conductive film 152f. The resist mask 191 can be formed by applying a photosensitive material (photoresist) and performing exposure and development.

[0325] Subsequently, as shown in FIG. 7(B), for example, the conductive film 151f and the conductive film 152f in a region that does not overlap with the resist mask 191 are removed using, for example, an etching method, specifically, for example, a dry etching method, to form a pixel electrode having a conductive layer 151 and a conductive layer 152. When the conductive film 151f includes a layer using a conductive oxide such as indium tin oxide, the layer may be removed using a wet etching method. Thereby, the conductive layer 151 and the conductive layer 152 are formed. When a part of the conductive film 151f is removed by a dry etching method, for example, a recess may be formed in a region that does not overlap with the conductive layer 151 of the insulating layer 175.

[0326] Note that after processing the conductive film 152f using a lithography method to form the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C, the conductive film 151f may be processed using the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C as masks. Specifically, for example, after forming a resist mask, a part of the conductive film 152f is removed by an etching method. The conductive film 152f can be removed, for example, by a wet etching method. Note that the conductive film 152f may be removed by a dry etching method. Thereafter, the conductive film 151f may be removed by a wet etching method.

[0327] Here, it is preferable to perform a hydrophobization treatment on the conductive layer 152. In the hydrophobization treatment, the surface to be treated can be changed from hydrophilic to hydrophobic, or the hydrophobicity of the surface to be treated can be enhanced. By performing the hydrophobization treatment on the conductive layer 152, the adhesion between the conductive layer 152 and the organic compound layer 103 formed in a later step can be enhanced, and film peeling can be suppressed. Note that the hydrophobization treatment may not be performed.

[0328] Subsequently, as shown in FIG. 7(C), the resist mask 191 is removed. The resist mask 191 can be removed, for example, by ashing using oxygen plasma. Alternatively, oxygen gas and a Group 18 element such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He may be used. Alternatively, the resist mask 191 may be removed by wet etching.

[0329] Subsequently, as shown in FIG. 7(D), an insulating film 156f that will later become the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, and the insulating layer 156C is formed on the conductive layer 151R and the conductive layer 152R, on the conductive layer 151G and the conductive layer 152G, on the conductive layer 151B and the conductive layer 152B, on the conductive layer 151C and the conductive layer 152C, and on the insulating layer 175. For the formation of the insulating film 156f, for example, a CVD method, an ALD method, a sputtering method, or a vacuum evaporation method can be used.

[0330] For the insulating film 156f, an inorganic material can be used. As the insulating film 156f, for example, an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitroxide insulating film can be used. For example, as the insulating film 156f, an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitroxide insulating film containing silicon can be used. For example, silicon oxynitride can be used as the insulating film 156f.

[0331] Subsequently, as shown in FIG. 7(E), by processing the insulating film 156f, an insulating layer 156R, an insulating layer 156G, an insulating layer 156B, and an insulating layer 156C are formed. For example, by performing etching substantially uniformly on the upper surface of the insulating film 156f, the insulating layer 156 can be formed. Such uniform etching and planarization is also referred to as etch-back processing. Note that the insulating layer 156 may be formed using a lithography method.

[0332] Subsequently, as shown in FIG. 8(A), an organic compound film 103Rf that will later become the organic compound layer 103R is formed on the conductive layer 152R, on the conductive layer 152G, on the conductive layer 152B, on the insulating layer 156R, on the insulating layer 156G, on the insulating layer 156B, and on the insulating layer 175.

[0333] As shown in FIG. 8(A), the organic compound film 103Rf is not formed on the conductive layer 152C. For example, by using a mask for defining the film formation area (also referred to as an area mask or a rough metal mask, etc., distinguished from a fine metal mask), the organic compound film 103Rf can be formed only in a desired region. By adopting a film formation process using an area mask and a processing process using a resist mask, a light-emitting device can be manufactured with a relatively simple process.

[0334] The organic compound film 103Rf can be formed, for example, by a vapor deposition method, specifically, a vacuum vapor deposition method. Further, the organic compound film 103Rf may be formed by a method such as a transfer method, a printing method, an inkjet method, or a coating method.

[0335] Subsequently, as shown in FIG. 8(A), a sacrificial film 158Rf that will later become the sacrificial layer 158R and a mask film 159Rf that will later become the mask layer 159R are sequentially formed on the organic compound film 103Rf, on the conductive layer 152C, and on the insulating layer 175.

[0336] In this embodiment, an example of forming a mask film with a two-layer structure of a sacrificial film 158Rf and a mask film 159Rf is shown. However, the mask film may have a single-layer structure or a laminated structure of three or more layers. Also, in this specification and the like, the mask layer may be referred to as the sacrificial layer.

[0337] By providing a sacrificial layer on the organic compound film 103Rf, damage to the organic compound film 103Rf during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be enhanced.

[0338] For the sacrificial film 158Rf, a film with high resistance to the processing conditions of the organic compound film 103Rf is used. Specifically, a film with a large etching selectivity ratio with respect to the organic compound film 103Rf is used. For the mask film 159Rf, a film with a large etching selectivity ratio with respect to the sacrificial film 158Rf is used.

[0339] Also, the sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the heat-resistant temperature of the organic compound film 103Rf. As the substrate temperature when forming the sacrificial film 158Rf and the mask film 159Rf, typically, they are each 200°C or lower, preferably 150°C or lower, more preferably 120°C or lower, still more preferably 100°C or lower, and even more preferably 80°C or lower.

[0340] It is preferable to use a film that can be removed by a wet etching method for the sacrificial film 158Rf and the mask film 159Rf. By using the wet etching method, damage to the organic compound film 103Rf during the processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced compared to the case of using a dry etching method.

[0341] For the formation of the sacrificial film 158Rf and the mask film 159Rf, for example, a sputtering method, an ALD method (thermal ALD method, PEALD method), a CVD method, or a vacuum evaporation method can be used. Alternatively, the above-described wet film formation method may be used.

[0342] Note that the sacrificial film 158Rf formed in contact with the organic compound film 103Rf is preferably formed using a film formation method that causes less damage to the organic compound film 103Rf than the mask film 159Rf. For example, it is preferable to form the sacrificial film 158Rf using an ALD method or a vacuum evaporation method rather than a sputtering method.

[0343] As the sacrificial film 158Rf and the mask film 159Rf, one or more of, for example, a metal film, an alloy film, a metal oxide film, a semiconductor film, an organic insulating film, and an inorganic insulating film can be used respectively.

[0344] For the sacrificial film 158Rf and the mask film 159Rf, respectively, for example, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing the metal materials can be used. In particular, it is preferable to use a low melting point material such as aluminum or silver. By using a metal material capable of shielding ultraviolet rays for one or both of the sacrificial film 158Rf and the mask film 159Rf, irradiation of the organic compound film 103Rf with ultraviolet rays can be suppressed, and deterioration of the organic compound film 103Rf can be suppressed, which is preferable.

[0345] In addition, for the sacrificial film 158Rf and the mask film 159Rf, respectively, metal oxides such as In-Ga-Zn oxide, indium oxide, In-Zn oxide, In-Sn oxide, indium titanate (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), and indium tin oxide containing silicon can be used.

[0346] Note that instead of the above-mentioned gallium, an element M (M is one or more selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) may be used.

[0347] Also, as the sacrificial film and the mask film, it is preferable to use a film containing a material having light-shielding properties against light, particularly ultraviolet light. As the material having light-shielding properties, various materials such as metals, insulators, semiconductors, and semimetals having light-shielding properties against ultraviolet light can be used. However, since a part or all of the sacrificial film and the mask film are removed in a later process, it is preferably a film that can be processed by etching, and particularly preferably a film having good processability.

[0348] As the sacrificial film and the mask film, for example, semiconductor materials such as silicon or germanium are preferable because they have high affinity with the semiconductor manufacturing process. Or, oxides or nitrides of the above semiconductor materials can be used. Or, non-metal materials such as carbon or their compounds can be used. Or, metals such as titanium, tantalum, tungsten, chromium, aluminum, or alloys containing one or more of these can be mentioned. Or, oxides containing the above metals such as titanium oxide or chromium oxide, or nitrides such as titanium nitride, chromium nitride, or tantalum nitride can be used.

[0349] By using a film containing a material having light-shielding properties against ultraviolet light for the sacrificial film and the mask film, for example, it is possible to suppress the irradiation of ultraviolet light to the organic compound layer in the exposure process. By suppressing the damage of the organic compound layer by ultraviolet light, the reliability of the light-emitting device can be improved.

[0350] Note that the film containing a material having light-shielding properties against ultraviolet light can also exhibit the same effect when used as the material of the inorganic insulating film 125f described later.

[0351] In addition, various inorganic insulating films can be used as the sacrificial film 158Rf and the mask film 159Rf, respectively. In particular, the oxide insulating film is preferable because it has higher adhesion to the organic compound film 103Rf than the nitride insulating film. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used for the sacrificial film 158Rf and the mask film 159Rf, respectively. As the sacrificial film 158Rf and the mask film 159Rf, for example, an aluminum oxide film can be formed using the ALD method. Using the ALD method is preferable because damage to the substrate (especially the organic compound layer) can be reduced.

[0352] For example, an inorganic insulating film (e.g., an aluminum oxide film) formed using the ALD method can be used as the sacrificial film 158Rf, and an inorganic film (e.g., an In-Ga-Zn oxide film, an aluminum film, or a tungsten film) formed using the sputtering method can be used as the mask film 159Rf.

[0353] Note that the same inorganic insulating film can be used for both the sacrificial film 158Rf and the inorganic insulating layer 125 formed later. For example, an aluminum oxide film formed using the ALD method can be used for both the sacrificial film 158Rf and the inorganic insulating layer 125. Here, the same film formation conditions may be applied to the sacrificial film 158Rf and the inorganic insulating layer 125, or different film formation conditions may be applied to each other. For example, by forming the sacrificial film 158Rf under the same conditions as the inorganic insulating layer 125, the sacrificial film 158Rf can be made into an insulating layer with high barrier properties against at least one of water and oxygen. On the other hand, since the sacrificial film 158Rf is a layer that is mostly or entirely removed in a later process, it is preferably easy to process. For this reason, the sacrificial film 158Rf is preferably formed under conditions where the substrate temperature during film formation is lower than that of the inorganic insulating layer 125.

[0354] One or both of the sacrificial film 158Rf and the mask film 159Rf may use an organic material. For example, as the organic material, a material that can be dissolved in a chemically stable solvent may be used for at least the film located at the top of the organic compound film 103Rf. In particular, a material that dissolves in water or alcohol can be preferably used. When forming a film of such a material, it is preferable to perform a heat treatment for evaporating the solvent after coating in a wet film forming method in a state of being dissolved in a solvent such as water or alcohol. At this time, by performing the heat treatment under a reduced pressure atmosphere, the solvent can be removed at a low temperature and in a short time, so that thermal damage to the organic compound film 103Rf can be reduced, which is preferable.

[0355] For the sacrificial film 158Rf and the mask film 159Rf, organic resins such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, alcohol-soluble polyamide resin, or fluororesin such as perfluoropolymer may be used respectively.

[0356] For example, as the sacrificial film 158Rf, an organic film (for example, a PVA film) formed by using either a vapor deposition method or the above wet film forming method can be used, and as the mask film 159Rf, an inorganic film (for example, a silicon nitride film) formed by using a sputtering method can be used.

[0357] Subsequently, as shown in FIG. 8(A), a resist mask 190R is formed on the mask film 159Rf. The resist mask 190R can be formed by applying a photosensitive material (photoresist) and performing exposure and development.

[0358] The resist mask 190R may be produced using either a positive resist material or a negative resist material.

[0359] The resist mask 190R is provided at a position overlapping with the conductive layer 152R. It is preferable to also provide the resist mask 190R at a position overlapping with the conductive layer 152C. Thereby, it is possible to suppress the conductive layer 152C from being damaged during the manufacturing process of the display device. Note that it is not necessary to provide the resist mask 190R on the conductive layer 152C. Further, as shown in the cross-sectional view between B1 - B2 in FIG. 8(A), the resist mask 190R is preferably provided so as to cover from the end of the organic compound film 103Rf to the end of the conductive layer 152C (the end on the organic compound film 103Rf side).

[0360] Subsequently, as shown in FIG. 8(B), using the resist mask 190R, a part of the mask film 159Rf is removed to form the mask layer 159R. The mask layer 159R remains on the conductive layer 152R and on the conductive layer 152C. Thereafter, the resist mask 190R is removed. Subsequently, using the mask layer 159R as a mask (also referred to as a hard mask), a part of the sacrificial film 158Rf is removed to form the sacrificial layer 158R.

[0361] The sacrificial film 158Rf and the mask film 159Rf can each be processed by a wet etching method or a dry etching method. The processing of the sacrificial film 158Rf and the mask film 159Rf is preferably performed by isotropic etching.

[0362] By using the wet etching method, the damage applied to the organic compound film 103Rf during the processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced as compared with the case of using the dry etching method. When using the wet etching method, for example, it is preferable to use a chemical solution using a developer, an aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed liquid thereof.

[0363] In the processing of the mask film 159Rf, since the organic compound film 103Rf is not exposed, the range of selection of the processing method is wider than that of the processing of the sacrificial film 158Rf. Specifically, when oxygen-containing gas is used as the etching gas during the processing of the mask film 159Rf, the deterioration of the organic compound film 103Rf can be more effectively suppressed.

[0364] Also, when the dry etching method is used in the processing of the sacrificial film 158Rf, the deterioration of the organic compound film 103Rf can be suppressed by not using oxygen-containing gas as the etching gas. When using the dry etching method, for example, it is preferable to use a gas containing a Group 18 element such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He as the etching gas.

[0365] For example, when an aluminum oxide film formed by the ALD method is used as the sacrificial film 158Rf, a part of the sacrificial film 158Rf can be removed by the dry etching method using CHF3 and He, or CHF3, He, and CH4. Also, when an In-Ga-Zn oxide film formed by the sputtering method is used as the mask film 159Rf, a part of the mask film 159Rf can be removed by the wet etching method using diluted phosphoric acid. Or, a part of the mask film 159Rf may be removed by the dry etching method using CH4 and Ar. Or, a part of the mask film 159Rf can be removed by the wet etching method using diluted phosphoric acid. Also, when a tungsten film formed by the sputtering method is used as the mask film 159Rf, a part of the mask film 159Rf can be removed by the dry etching method using SF6, CF4 and O2, or CF4, Cl2 and O2.

[0366] The resist mask 190R can be removed in the same manner as the resist mask 191. For example, it can be removed by ashing using oxygen plasma. Alternatively, oxygen gas and a Group 18 element such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He may be used. Alternatively, the resist mask 190R may be removed by wet etching. At this time, since the sacrificial film 158Rf is located on the outermost surface and the organic compound film 103Rf is not exposed, damage to the organic compound film 103Rf can be suppressed in the process of removing the resist mask 190R. In addition, the range of selection of the method for removing the resist mask 190R can be widened.

[0367] Subsequently, as shown in FIG. 8(B), the organic compound film 103Rf is processed to form an organic compound layer 103R. For example, the mask layer 159R and the sacrificial layer 158R are used as a hard mask to remove a part of the organic compound film 103Rf to form an organic compound layer 103R.

[0368] As a result, as shown in FIG. 8(B), a stacked structure of the organic compound layer 103R, the sacrificial layer 158R, and the mask layer 159R remains on the conductive layer 152R. Also, the conductive layer 152G and the conductive layer 152B are exposed.

[0369] FIG. 8(B) shows an example in which the end of the organic compound layer 103R is located inside the end of the conductive layer 152R. With such a configuration, miniaturization of the pixel becomes possible, and a high-definition display can be created. Although not shown in FIG. 8(B), depending on the above etching process, recesses may be formed in a region that does not overlap with the organic compound layer 103R of the insulating layer 175.

[0370] As described above, it is preferable that the resist mask 190R is provided so as to cover from the end of the organic compound layer 103R to the end of the conductive layer 152C (the end on the organic compound layer 103R side) between the dashed-dotted lines B1 - B2. Thereby, as shown in FIG. 8(B), the sacrificial layer 158R and the mask layer 159R are provided so as to cover from the end of the organic compound layer 103R to the end of the conductive layer 152C (the end on the organic compound layer 103R side) between the dashed-dotted lines B1 - B2. Thus, for example, between the dashed-dotted lines B1 - B2, it is possible to suppress the exposure of the insulating layer 175. Thereby, it is possible to prevent a part of the insulating layer 175, the insulating layer 174, and the insulating layer 173 from being removed by etching or the like and the conductive layer 179 from being exposed. For this reason, it is possible to suppress the conductive layer 179 from being electrically connected to another conductive layer unintentionally. For example, it is possible to suppress a short circuit between the conductive layer 179 and the common electrode 155 formed in a later process.

[0371] The processing of the organic compound film 103Rf is preferably performed by anisotropic etching. In particular, anisotropic dry etching is preferable. Alternatively, wet etching may be used.

[0372] When using the dry etching method, deterioration of the organic compound film 103Rf can be suppressed by not using a gas containing oxygen as the etching gas.

[0373] Also, a gas containing oxygen may be used as the etching gas. Since the etching gas contains oxygen, the etching rate can be increased. Therefore, etching can be performed under low-power conditions while maintaining the etching rate at a sufficient speed. For this reason, damage to the organic compound film 103Rf can be suppressed. Furthermore, problems such as adhesion of reaction products generated during etching can be suppressed.

[0374] When using a dry etching method, for example, it is preferable to use a gas containing one or more of H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or Group 18 elements such as He and Ar as the etching gas. Alternatively, it is preferable to use a gas containing one or more of these and a gas containing oxygen as the etching gas. Alternatively, oxygen gas may be used as the etching gas. Specifically, for example, a gas containing H2 and Ar, or a gas containing CF4 and He can be used as the etching gas. Also, for example, a gas containing CF4, He, and oxygen can be used as the etching gas. Also, for example, a gas containing H2 and Ar and a gas containing oxygen can be used as the etching gas.

[0375] As described above, in one aspect of the present invention, a resist mask 190R is formed on the mask film 159Rf, and a part of the mask film 159Rf is removed using the resist mask 190R to form the mask layer 159R. Then, using the mask layer 159R as a hard mask, a part of the organic compound film 103Rf is removed to form the organic compound layer 103R. Therefore, it can be said that the organic compound layer 103R is formed by processing the organic compound film 103Rf using a lithography method. Note that a part of the organic compound film 103Rf may be removed using the resist mask 190R. Then, the resist mask 190R may be removed.

[0376] Next, for example, it is preferable to perform a hydrophobization treatment on the conductive layer 152G. When processing the organic compound film 103Rf, for example, the surface state of the conductive layer 152G may change to hydrophilic. By performing a hydrophobization treatment on the conductive layer 152G, for example, the adhesion between the conductive layer 152G and a layer formed in a later process (here, the organic compound layer 103G) can be enhanced, and film peeling can be suppressed. Note that the hydrophobization treatment may not be performed.

[0377] Subsequently, as shown in FIG. 9(A), an organic compound film 103Gf that will later become the organic compound layer 103G is formed on the conductive layer 152G, on the conductive layer 152B, on the insulating layer 156R, on the insulating layer 156G, on the insulating layer 156B, on the mask layer 159R, and on the insulating layer 175.

[0378] The organic compound film 103Gf can be formed by the same method as the method used for forming the organic compound film 103Rf. Also, the organic compound film 103Gf can have the same configuration as the organic compound film 103Rf.

[0379] Subsequently, as shown in FIG. 9(A), on the organic compound film 103Gf and on the mask layer 159R, a sacrificial film 158Gf that will later become the sacrificial layer 158G and a mask film 159Gf that will later become the mask layer 159G are sequentially formed. Thereafter, a resist mask 190G is formed. The materials and formation methods of the sacrificial film 158Gf and the mask film 159Gf are the same as the conditions applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods of the resist mask 190G are the same as the conditions applicable to the resist mask 190R.

[0380] The resist mask 190G is provided at a position overlapping with the conductive layer 152G.

[0381] Subsequently, as shown in FIG. 9(B), using the resist mask 190G, a part of the mask film 159Gf is removed to form the mask layer 159G. The mask layer 159G remains on the conductive layer 152G. Thereafter, the resist mask 190G is removed. Subsequently, using the mask layer 159G as a mask, a part of the sacrificial film 158Gf is removed to form the sacrificial layer 158G. Subsequently, the organic compound film 103Gf is processed to form the organic compound layer 103G. For example, using the mask layer 159G and the sacrificial layer 158G as hard masks, a part of the organic compound film 103Gf is removed to form the organic compound layer 103G.

[0382] As a result, as shown in FIG. 9(B), a laminated structure of the organic compound layer 103G, the sacrificial layer 158G, and the mask layer 159G remains on the conductive layer 152G. Also, the mask layer 159R and the conductive layer 152B are exposed.

[0383] Next, for example, it is preferable to perform a hydrophobization treatment on the conductive layer 152B. When processing the organic compound film 103Gf, for example, the surface state of the conductive layer 152B may change to hydrophilic. By performing a hydrophobization treatment on the conductive layer 152B, for example, the adhesion between the conductive layer 152B and a layer formed in a subsequent process (here, the organic compound layer 103B) can be enhanced, and film peeling can be suppressed. Note that the hydrophobization treatment may not be performed.

[0384] Subsequently, as shown in FIG. 9(C), an organic compound film 103Bf that will later become the organic compound layer 103B is formed on the conductive layer 152B, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, the mask layer 159R, the mask layer 159G, and the insulating layer 175.

[0385] The organic compound film 103Bf can be formed by the same method as the method used to form the organic compound film 103Rf. Also, the organic compound film 103Bf can have the same configuration as the organic compound film 103Rf.

[0386] Subsequently, as shown in FIG. 9(C), a sacrificial film 158Bf that will later become the sacrificial layer 158B and a mask film 159Bf that will later become the mask layer 159B are sequentially formed on the organic compound film 103Bf and the mask layer 159R. Then, a resist mask 190B is formed. The materials and formation methods of the sacrificial film 158Bf and the mask film 159Bf are the same as the conditions applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods of the resist mask 190B are the same as the conditions applicable to the resist mask 190R.

[0387] The resist mask 190B is provided at a position overlapping the conductive layer 152B.

[0388] Subsequently, as shown in FIG. 9(D), using the resist mask 190B, a part of the mask film 159Bf is removed to form the mask layer 159B. The mask layer 159B remains on the conductive layer 152B. Thereafter, the resist mask 190B is removed. Subsequently, using the mask layer 159B as a mask, a part of the sacrificial film 158Bf is removed to form the sacrificial layer 158B. Subsequently, the organic compound film 103Bf is processed to form the organic compound layer 103B. For example, using the mask layer 159B and the sacrificial layer 158B as hard masks, a part of the organic compound film 103Bf is removed to form the organic compound layer 103B.

[0389] As a result, as shown in FIG. 9(D), a stacked structure of the organic compound layer 103B, the sacrificial layer 158B, and the mask layer 159B remains on the conductive layer 152B. Also, the mask layer 159R and the mask layer 159G are exposed.

[0390] Note that the side surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are preferably perpendicular or substantially perpendicular to the formation surface. For example, the angle formed by the formation surface and these side surfaces is preferably 60 degrees or more and 90 degrees or less.

[0391] As described above, the distance between two adjacent ones of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B formed by using the lithography method can be narrowed to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Here, the distance can be defined as, for example, the distance between two opposing end portions of two adjacent ones among the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. By narrowing the distance between the island-shaped organic compound layers in this way, a display device having high definition and a large aperture ratio can be provided. Also, the distance between the first electrodes between adjacent light-emitting devices can also be narrowed, and can be, for example, 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less. Note that the distance between the first electrodes between adjacent light-emitting devices is preferably 2 μm or more and 5 μm or less.

[0392] Subsequently, as shown in FIG. 10(A), it is preferable to remove the mask layer 159R, the mask layer 159G, and the mask layer 159B. Depending on subsequent processes, the sacrificial layer 158R, the sacrificial layer 158G, the sacrificial layer 158B, the mask layer 159R, the mask layer 159G, and the mask layer 159B may remain in the display device. By removing the mask layer 159R, the mask layer 159G, and the mask layer 159B at this stage, it is possible to suppress the remaining of the mask layer 159R, the mask layer 159G, and the mask layer 159B in the display device. For example, when a conductive material is used for the mask layer 159R, the mask layer 159G, and the mask layer 159B, by removing the mask layer 159R, the mask layer 159G, and the mask layer 159B in advance, it is possible to suppress the generation of leakage current and the formation of capacitance due to the remaining mask layer 159R, the mask layer 159G, and the mask layer 159B.

[0393] In this embodiment, the case of removing the mask layer 159R, the mask layer 159G, and the mask layer 159B is taken as an example for explanation, but the mask layer 159R, the mask layer 159G, and the mask layer 159B may not be removed. For example, when the mask layer 159R, the mask layer 159G, and the mask layer 159B contain a material having light-shielding properties with respect to ultraviolet rays as described above, it is preferable to proceed to the next step without removing them, so that the organic compound layer can be protected from ultraviolet rays.

[0394] For the mask layer removal process, the same method as the mask film processing process can be used. In particular, by using the wet etching method, compared with the case of using the dry etching method, when removing the mask layer, the damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced.

[0395] Alternatively, the mask layer may be removed by dissolving it in a solvent such as water or alcohol. Examples of alcohol include ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0396] After removing the mask layer, a drying process may be performed to remove water contained in the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, as well as water adsorbed on the surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. For example, heat treatment can be performed under an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, more preferably 70°C or higher and 120°C or lower as the substrate temperature. Making it a reduced pressure atmosphere is preferable because drying can be performed at a lower temperature.

[0397] Subsequently, as shown in FIG. 10(B), an inorganic insulating film 125f that will later become the inorganic insulating layer 125 is formed so as to cover the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B.

[0398] As will be described later, an insulating film that will later become the insulating layer 127 is formed in contact with the upper surface of the inorganic insulating film 125f. For this reason, it is preferable that the upper surface of the inorganic insulating film 125f has high affinity for the material used for the insulating film (for example, a photosensitive resin composition containing an acrylic resin). In order to improve the affinity, it is preferable to perform surface treatment to hydrophobize (or increase the hydrophobicity of) the upper surface of the inorganic insulating film 125f. For example, it is preferable to perform treatment using a silylating agent such as hexamethyldisilazane (HMDS). By hydrophobizing the upper surface of the inorganic insulating film 125f in this way, the insulating film 127f can be formed with good adhesion. Note that, as the surface treatment, the aforementioned hydrophobization treatment may be performed.

[0399] Subsequently, as shown in FIG. 10(C), an insulating film 127f that will later become the insulating layer 127 is formed on the inorganic insulating film 125f.

[0400] The inorganic insulating film 125f and the insulating film 127f are preferably formed by a forming method that causes little damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. In particular, since the inorganic insulating film 125f is formed in contact with the side surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, it is preferably formed by a forming method that causes less damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B than the insulating film 127f.

[0401] Also, the inorganic insulating film 125f and the insulating film 127f are each formed at a temperature lower than the heat resistance temperature of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. Further, by increasing the substrate temperature during the formation of the inorganic insulating film 125f, even if the film thickness is thin, a film with a low impurity concentration and high barrier properties against at least one of water and oxygen can be obtained.

[0402] The substrate temperature during the formation of the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher, and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower, respectively.

[0403] As the inorganic insulating film 125f, it is preferable to form an insulating film with a thickness of 3 nm or more, 5 nm or more, or 10 nm or more, and 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less within the above range of the substrate temperature.

[0404] The inorganic insulating film 125f is preferably formed using, for example, the ALD method. Using the ALD method is preferable because film formation damage can be reduced and a film with high coating properties can be formed. As the inorganic insulating film 125f, it is preferable to form an aluminum oxide film using, for example, the ALD method.

[0405] In addition, the inorganic insulating film 125f may be formed using a sputtering method, a CVD method, or a PECVD method, which has a higher film formation rate than the ALD method. Thereby, a highly reliable display device can be manufactured with high productivity.

[0406] The insulating film 127f is preferably formed using the above-described wet film formation method. The insulating film 127f is preferably formed, for example, by spin coating using a photosensitive material, and more specifically, is preferably formed using a photosensitive resin composition containing an acrylic resin.

[0407] The insulating film 127f is preferably formed using, for example, a resin composition having a polymer, an acid generator, and a solvent. The polymer is formed using one or more monomers and has a structure in which one or more structural units (also referred to as constituent units) are repeated regularly or irregularly. As the acid generator, one or both of a compound that generates an acid upon irradiation with light and a compound that generates an acid upon heating can be used. The resin composition may further have one or more of a photosensitizer, a sensitizer, a catalyst, an adhesion aid, a surfactant, and an antioxidant.

[0408] Also, it is preferable to perform a heat treatment (also referred to as pre-baking) after the formation of the insulating film 127f. The heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. The substrate temperature during the heat treatment is preferably 50°C or higher and 200°C or lower, more preferably 60°C or higher and 150°C or lower, and even more preferably 70°C or higher and 120°C or lower. Thereby, the solvent contained in the insulating film 127f can be removed.

[0409] Subsequently, exposure is performed to make a part of the insulating film 127f sensitive to visible light or ultraviolet light. Here, when a positive photosensitive resin composition containing an acrylic resin is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the region where the insulating layer 127 is not formed in a later process. The insulating layer 127 is formed in a region sandwiched between any two of the conductive layer 152R, the conductive layer 152G, and the conductive layer 152B, and around the conductive layer 152C. Therefore, visible light or ultraviolet light is irradiated onto the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C. Note that when a negative photosensitive material is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the region where the insulating layer 127 is formed.

[0410] The width of the insulating layer 127 to be formed later can be controlled by the exposure region of the insulating film 127f. In the present embodiment, processing is performed such that the insulating layer 127 has a portion overlapping with the upper surface of the conductive layer 151.

[0411] The light used for exposure preferably includes i-line (wavelength 365 nm). Further, the light used for exposure may include at least one of g-line (wavelength 436 nm) and h-line (wavelength 405 nm).

[0412] Here, by providing an oxygen barrier insulating layer (for example, an aluminum oxide film, etc.) as one or both of the sacrificial layer 158 (sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B) and the inorganic insulating film 125f, the diffusion of oxygen into the organic compound layers 103R, 103G, and 103B can be reduced. When the organic compound layer is irradiated with light (visible light or ultraviolet light), the organic compound contained in the organic compound layer may be in an excited state, and the reaction with oxygen contained in the atmosphere may be promoted. More specifically, in an atmosphere containing oxygen, when the organic compound layer is irradiated with light (visible light or ultraviolet light), oxygen may bind to the organic compound contained in the organic compound layer. By providing the sacrificial layer 158 and the inorganic insulating film 125f on the island-shaped organic compound layer, the binding of oxygen in the atmosphere to the organic compound contained in the organic compound layer can be reduced.

[0413] Subsequently, as shown in FIG. 11(A), development is performed to remove the exposed area of the insulating film 127f and form the insulating layer 127a. The insulating layer 127a is formed in a region sandwiched between any two of the conductive layer 152R, the conductive layer 152G, and the conductive layer 152B, and in a region surrounding the conductive layer 152C. Here, when an acrylic resin is used for the insulating film 127f, an alkaline solution can be used as the developer, for example, TMAH can be used.

[0414] Subsequently, residues (so-called scum) during development may be removed. For example, the residues can be removed by performing ashing using oxygen plasma.

[0415] Note that etching may be performed to adjust the height of the surface of the insulating layer 127a. The insulating layer 127a may be processed, for example, by ashing using oxygen plasma. Also, even when a non-photosensitive material is used for the insulating film 127f, for example, the height of the surface of the insulating film 127f can be adjusted by the ashing.

[0416] Subsequently, as shown in FIG. 11(B), an etching process is performed using the insulating layer 127a as a mask to remove a part of the inorganic insulating film 125f and reduce the film thickness of a part of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. Thereby, an inorganic insulating layer 125 is formed under the insulating layer 127a. Also, the surfaces of the portions where the film thicknesses of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are thin are exposed. Hereinafter, the etching process using the insulating layer 127a as a mask may be referred to as the first etching process.

[0417] The first etching process can be performed by dry etching or wet etching. Note that when the inorganic insulating film 125f is formed using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, it is preferable because the first etching process can be performed in a batch.

[0418] By performing etching using the insulating layer 127a having a tapered shape on its side surface as a mask, the side surfaces of the inorganic insulating layer 125 and the upper end portions of the side surfaces of the sacrificial layers 158R, 158G, and 158B can be made into a tapered shape relatively easily.

[0419] When performing dry etching, it is preferable to use a chlorine-based gas. As the chlorine-based gas, Cl2, BCl3, SiCl4, CCl4, etc. can be used alone or in combination of two or more gases. Further, oxygen gas, hydrogen gas, helium gas, argon gas, etc. can be appropriately added to the above chlorine-based gas, either alone or in combination of two or more gases. By using dry etching, regions with a thin film thickness of the sacrificial layers 158R, 158G, and 158B can be formed with good in-plane uniformity.

[0420] As the dry etching apparatus, a dry etching apparatus having a high-density plasma source can be used. As the dry etching apparatus having a high-density plasma source, for example, an inductively coupled plasma (ICP) etching apparatus can be used. Alternatively, a capacitively coupled plasma (CCP) etching apparatus having parallel plate electrodes can be used. The capacitively coupled plasma etching apparatus having parallel plate electrodes may be configured to apply a high-frequency voltage to one of the parallel plate electrodes. Alternatively, it may be configured to apply a plurality of different high-frequency voltages to one of the parallel plate electrodes. Alternatively, it may be configured to apply a high-frequency voltage of the same frequency to each of the parallel plate electrodes. Alternatively, it may be configured to apply high-frequency voltages of different frequencies to each of the parallel plate electrodes.

[0421] Further, when performing dry etching, by-products generated by dry etching may accumulate on the upper surface and side surfaces of the insulating layer 127a. For this reason, components contained in the etching gas, components contained in the inorganic insulating film 125f, components contained in the sacrificial layers 158R, 158G, and 158B, etc. may be contained in the insulating layer 127 after the display device is completed.

[0422] Also, it is preferable to perform the first etching process by wet etching. By using the wet etching method, the damage applied to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced as compared with the case of using the dry etching method. For example, wet etching can be performed using an alkaline solution. For example, TMAH, which is an alkaline solution, can be used for wet etching of the aluminum oxide film. In this case, wet etching can be performed by the paddle method. In addition, when the inorganic insulating film 125f is formed using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, it is preferable because the above etching process can be performed collectively.

[0423] In the first etching process, the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are not completely removed, and the etching process is stopped in a state where the film thickness is reduced. In this way, by leaving the corresponding sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B on the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, it is possible to prevent the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B from being damaged in the subsequent process.

[0424] Subsequently, it is preferable to expose the entire substrate and irradiate the insulating layer 127a with visible light or ultraviolet light. The energy density of the exposure is preferably greater than 0 mJ / cm 2 and less than or equal to 800 mJ / cm 2 more preferably greater than 0 mJ / cm 2 and less than or equal to 500 mJ / cm 2 Performing such exposure after development may improve the transparency of the insulating layer 127a. In addition, in a subsequent process, the substrate temperature required for the heat treatment for deforming the insulating layer 127a into a tapered shape may be reduced.

[0425] Here, as the sacrificial layers 158R, 158G, and 158B, the presence of a barrier insulating layer against oxygen (e.g., an aluminum oxide film or the like) can reduce the diffusion of oxygen into the organic compound layers 103R, 103G, and 103B. When the organic compound layer is irradiated with light (visible light or ultraviolet light), the organic compounds contained in the organic compound layer may be excited, and the reaction with oxygen contained in the atmosphere may be promoted. More specifically, when the organic compound layer is irradiated with light (visible light or ultraviolet light) in an atmosphere containing oxygen, oxygen may bind to the organic compounds contained in the organic compound layer. By providing the sacrificial layers 158R, 158G, and 158B on the island-shaped organic compound layer, it is possible to reduce the binding of oxygen in the atmosphere to the organic compounds contained in the organic compound layer.

[0426] Subsequently, a heat treatment (also referred to as post-bake) is performed. By performing the heat treatment, the insulating layer 127a can be deformed into an insulating layer 127 having a tapered shape on the side surface (FIG. 11(C)). The heat treatment is performed at a temperature lower than the heat-resistant temperature of the organic compound layer. The heat treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, more preferably 70°C or higher and 130°C or lower. The heating atmosphere may be an air atmosphere or an inert gas atmosphere. Also, the heating atmosphere may be an atmospheric pressure atmosphere or a reduced pressure atmosphere. It is preferable that the substrate temperature in the heat treatment of this step is higher than that in the heat treatment (pre-bake) after the formation of the insulating film 127f. Thereby, the adhesion between the insulating layer 127 and the inorganic insulating layer 125 can be improved, and the corrosion resistance of the insulating layer 127 can also be improved.

[0427] In the first etching process, by not completely removing the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, but leaving the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B in a state where the film thickness is reduced, it is possible to prevent the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B from being damaged and deteriorated during the heat treatment. Therefore, the reliability of the light-emitting device can be improved.

[0428] Note that depending on the material of the insulating layer 127, and the temperature, time, and atmosphere of the post-baking, a concave curved surface shape may be formed on the side surface of the insulating layer 127. For example, under the post-baking conditions, the higher the temperature or the longer the time, the more likely the shape of the insulating layer 127 is to change, and a concave curved surface shape may be formed.

[0429] Subsequently, as shown in FIG. 12(A), using the insulating layer 127 as a mask, an etching process is performed to remove a part of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. Note that a part of the inorganic insulating layer 125 may also be removed. As a result, openings are formed in each of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, and the upper surfaces of the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, and the conductive layer 152C are exposed. Note that hereinafter, the etching process using the insulating layer 127 as a mask may be referred to as the second etching process.

[0430] The end portion of the inorganic insulating layer 125 is covered with the insulating layer 127. Further, FIG. 12(A) shows an example in which a part of the end portion of the sacrificial layer 158G (specifically, the tapered portion formed by the first etching process) is covered with the insulating layer 127, and the tapered portion formed by the second etching process is exposed.

[0431] If the first etching process is not performed and the inorganic insulating layer 125 and the mask layer are etched all at once after post-baking, side etching may cause the inorganic insulating layer 125 and the mask layer under the end of the insulating layer 127 to disappear, forming a cavity. Due to this cavity, unevenness may occur on the surface where the common electrode 155 is formed, and the common electrode 155 is likely to have a step break. Even if the inorganic insulating layer 125 and the mask layer are side-etched in the first etching process to form a cavity, the insulating layer 127 can fill the cavity by performing post-baking thereafter. Then, in the second etching process, since the mask layer with a smaller thickness is etched, the amount of side etching is small, and it is difficult to form a cavity. Even if a cavity is formed, it can be made extremely small. Therefore, the surface where the common electrode 155 is formed can be made flatter.

[0432] Note that the insulating layer 127 may cover the entire end of the sacrificial layer 158G. For example, the end of the insulating layer 127 may sag and cover the end of the sacrificial layer 158G. Also, for example, the end of the insulating layer 127 may be in contact with the upper surface of at least one of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. As described above, when the developed insulating layer 127a is not exposed, the shape of the insulating layer 127 may easily change.

[0433] The second etching process is performed by wet etching. By using the wet etching method, the damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced compared to the case of using the dry etching method. Wet etching can be performed using an alkaline solution such as TMAH, for example.

[0434] On the other hand, when performing the second etching process using a wet etching method, for example, due to the problem of adhesion between the organic compound layer 103 and other layers, if there are gaps at the interfaces between the organic compound layer 103 and the sacrificial layer 158, between the organic compound layer 103 and the inorganic insulating layer 125, and between the organic compound layer 103 and the insulating layer 175, the chemical solution used in the second etching process may penetrate into the gaps and the chemical solution may come into contact with the pixel electrode. Here, when the chemical solution comes into contact with both the conductive layer 151 and the conductive layer 152, the conductive layer with a lower natural potential among the conductive layer 151 and the conductive layer 152 may be corroded by galvanic corrosion. For example, when aluminum is used as the conductive layer 151 and indium tin oxide is used as the conductive layer 152, the conductive layer 152 may be corroded. From the above, the yield of the display device may decrease. Also, the reliability of the display device may decrease.

[0435] As described above, by forming the insulating layer 156 so as to have a region overlapping with the side surface of the conductive layer 151 and forming the insulating layer 156 so as to cover the conductive layer 151 and the conductive layer 152, it is possible to prevent the step break of the inorganic insulating layer 125. Therefore, for example, in the second etching process, it is possible to prevent the chemical solution from coming into contact with the underlying structure such as the conductive layer 151. Thereby, corrosion of the pixel electrode can be prevented.

[0436] As described above, by providing the insulating layer 127, the inorganic insulating layer 125, the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, it is possible to suppress the occurrence of connection failures due to the disconnected portions and the increase in electrical resistance due to the locally thin film thickness portions in the common electrode 155 between the respective light-emitting devices. Thereby, the display device according to one aspect of the present invention can improve the display quality.

[0437] After exposing a part of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, further heat treatment is performed. By this heat treatment, water contained in each organic compound layer, water adsorbed on the surface of each organic compound layer, etc. can be removed. Also, the shape of the insulating layer 127 may change due to this heat treatment. Specifically, the insulating layer 127 may spread so as to cover at least one of the end portions of the inorganic insulating layer 125, the end portions of the sacrificial layers 158R, 158G, and 158B, and the upper surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B.

[0438] If the temperature of the heat treatment is too low, water contained in each organic compound layer, water adsorbed on the surface of each organic compound layer, etc. cannot be sufficiently removed. Also, if the temperature of the heat treatment is too high, deterioration of the organic compound layer 103 and excessive change in the shape of the insulating layer 127 may occur. Therefore, the heat treatment preferably has a temperature higher than the temperature at which water desorbs from the organic compound layer 103 and lower than the glass transition temperature of the organic compound contained in the organic compound layer 103, and preferably lower than the glass transition temperature of the organic compound contained on the upper surface of the organic compound layer 103. Specifically, it is preferably performed at a substrate temperature of 80°C or higher and 130°C or lower, preferably 90°C or higher and 120°C or lower, more preferably 100°C or higher and 120°C or lower, and even more preferably 100°C or higher and 110°C or lower. The heating atmosphere may be an air atmosphere or an inert gas atmosphere. Also, the heating atmosphere may be an atmospheric pressure atmosphere or a reduced pressure atmosphere, but a reduced pressure atmosphere is preferable so that the water desorbed from the organic compound layer 103 does not re-adsorb.

[0439] By this heat treatment, water contained in each organic compound layer, water adsorbed on the surface of each organic compound layer, etc. can be sufficiently removed without causing deterioration of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B and excessive change in the shape of the insulating layer 127. Thereby, a decrease in the characteristics of the light-emitting device can be prevented.

[0440] Subsequently, as shown in FIG. 12(B), a common layer 104 and a common electrode 155 are formed on the organic compound layer 103R, on the organic compound layer 103G, on the organic compound layer 103B, on the conductive layer 152C, and on the insulating layer 127. The common layer 104 and the common electrode 155 can be formed by methods such as a sputtering method or a vacuum evaporation method. The common layer 104 may be formed by an evaporation method and the common electrode 155 may be formed by a sputtering method.

[0441] Subsequently, as shown in FIG. 12(C), a protective layer 135 is formed on the common electrode 155. The protective layer 135 can be formed by methods such as a vacuum evaporation method, a sputtering method, a CVD method, or an ALD method.

[0442] Subsequently, the display device can be manufactured by bonding the substrate 120 onto the protective layer 135 using the resin layer 122. As described above, in the method for manufacturing a display device according to one aspect of the present invention, the insulating layer 156 is provided on the side surfaces of the conductive layer 151 and the conductive layer 152. Thereby, the yield of the display device can be increased and the occurrence of defects can be suppressed.

[0443] As described above, in the method for manufacturing a display device according to one aspect of the present invention, the island-shaped organic compound layer 103R, the island-shaped organic compound layer 103G, and the organic compound layer 103B are not formed using a fine metal mask, but are formed by processing after forming a film on one surface. Therefore, the island-shaped layers can be formed with a uniform thickness. Then, a high-definition display device or a display device with a high aperture ratio can be realized. Also, even if the fineness or aperture ratio is high and the distance between adjacent sub-pixels is extremely short, it is possible to suppress the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B from contacting each other in adjacent sub-pixels. Therefore, it is possible to suppress the generation of leakage current between sub-pixels. Thereby, crosstalk can be prevented and a display device with extremely high contrast can be realized. Also, even in a display device having a tandem type light-emitting device manufactured using a lithography method, a display device with good characteristics can be provided.

[0444] The configuration of the present embodiment can be used in appropriate combination with the configurations of other embodiments.

[0445] (Embodiment 4) In the present embodiment, a light-emitting device according to one aspect of the present invention will be described with reference to FIGS. 13(A) to 13(G) and...

Claims

1. A light-emitting device having a light-emitting layer between a pair of electrodes, the light-emitting layer includes a first compound, a material having a function of converting triplet excitation energy into luminescence, and a material having a function of converting singlet excitation energy into luminescence; At least one of the first compound and the material having a function of converting triplet excitation energy into luminescence contains deuterium; A light-emitting device in which light is emitted from a material having a function of converting the singlet excitation energy into light.

2. A light-emitting device having a light-emitting layer between a pair of electrodes, the light-emitting layer includes a first compound, a second compound, a material having a function of converting triplet excitation energy into light emission, and a material having a function of converting singlet excitation energy into light emission; At least one of the first compound, the second compound, and the material having a function of converting triplet excitation energy into luminescence contains deuterium; A light-emitting device in which light is emitted from a material having a function of converting the singlet excitation energy into light.

3. In claim 2 the first compound has a π-electron-deficient heteroaromatic ring, The second compound has at least one of a π-electron rich heteroaromatic ring and an aromatic amine skeleton.

4. In claim 2 A light-emitting device, wherein the difference between the lowest triplet excitation energy level of the first compound and the lowest triplet excitation energy level of the second compound is 0.20 eV or less.

5. In claim 2 the first compound and the second compound are a combination that forms an exciplex, A light-emitting device, wherein an emission spectrum of the exciplex overlaps with an emission spectrum of a material having a function of converting triplet excitation energy into light emission.

6. In any one of claims 1 to 5, the first compound having deuterium; A light-emitting device, wherein the phosphorescence lifetime or delayed fluorescence lifetime of the first compound at 77K is longer than the phosphorescence lifetime or delayed fluorescence lifetime of a non-deuterated form of the first compound at 77K.

7. In any one of claims 2 to 5, the second compound having deuterium; A light-emitting device, wherein the phosphorescence lifetime or delayed fluorescence lifetime of the second compound at 77K is longer than the phosphorescence lifetime or delayed fluorescence lifetime of a non-deuterated form of the second compound at 77K.

8. In any one of claims 1 to 5, the material having a function of converting triplet excitation energy into luminescence contains deuterium, A light-emitting device, wherein the phosphorescence lifetime or delayed fluorescence lifetime at room temperature of the material having the function of converting triplet excitation energy into light emission is longer than the phosphorescence lifetime or delayed fluorescence lifetime at room temperature of a non-deuterated form of the material having the function of converting triplet excitation energy into light emission.

9. In any one of claims 1 to 5, The material capable of converting triplet excitation energy into light emission is a phosphorescent material.

10. In any one of claims 1 to 5, The material capable of converting triplet excitation energy into light emission is a TADF material.

11. In any one of claims 1 to 5, A light-emitting device, wherein the material capable of converting singlet excitation energy into luminescence is a fluorescent substance.

12. In any one of claims 1 to 5, the material having a function of converting singlet excitation energy into luminescence is a fluorescent substance having a luminophore and a protecting group, the luminophore is a fused aromatic ring or a fused heteroaromatic ring; The protective group has any one of an alkyl group having from 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to 10 carbon atoms, and a trialkylsilyl group having from 3 to 10 carbon atoms.

13. 13. The light-emitting device of claim 12, wherein the protecting group comprises deuterium.

14. In any one of claims 1 to 5, A light-emitting device, wherein the material having a function of converting singlet excitation energy into light emission is a TADF material.

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