Organic electroluminescent element

Abstract

The present invention provides an organic electroluminescent element having an anode, a cathode, and a light-emitting layer between the anode and the cathode. Among them, the light-emitting layer contains at least a first organic compound, a second organic compound, and a third organic compound that satisfy the following formula (A), and the second organic compound is a delayed phosphor and the third organic compound is a light-emitting body, and the element has a high luminous efficiency. Formula (A) E S1 (A) > E S1 (B) > E S1 (C), where E S1 (A), E S1 (B), E S1 (C) respectively represent the lowest excited singlet energy levels of the first organic compound, the second organic compound, and the third organic compound.

Description

Technical Field

[0001] The present invention relates to an organic electroluminescent element having high luminous efficiency. Background Art

[0002] Research is actively being conducted to improve the luminous efficiency of organic light-emitting elements such as organic electroluminescent elements (organic EL elements). In particular, various studies have been conducted to improve the luminous efficiency by improving the materials used for the light-emitting layer. Among them, research related to organic electroluminescent elements in which the excitation energy generated in the host material is transferred to the guest material (luminescent dopant) to cause luminescence by using a host material and a guest material has also been found.

[0003] In Patent Document 1 and Patent Document 2, an organic electroluminescent element using a host material, a luminescent dopant, and an auxiliary dopant as materials for the light-emitting layer is disclosed. In this organic electroluminescent element, the auxiliary dopant supplements the movement of carriers in the light-emitting layer. For example, in the case of supplementing the movement of electrons, a hole mobility material such as an aniline derivative is used, and in the case of supplementing the movement of holes, an electron mobility material is used. In Patent Document 1 and Patent Document 2, it is described that by using such an auxiliary dopant, the probability of recombination of carriers becomes high, and thus the luminous efficiency of the organic electroluminescent element can be improved.

[0004] In Patent Document 3, an organic electroluminescent element using the following materials as materials for the light-emitting layer is disclosed, and an example of an organometallic complex having iridium as a central metal as a first dopant and a second dopant is described. The materials include a first dopant composed of a material capable of converting triplet excitation energy into luminescence and having a first energy gap, a second dopant composed of a material capable of converting triplet excitation energy into luminescence and having a second energy gap larger than the first energy gap, and a host material having a third energy gap larger than the second energy gap. In Patent Document 3, it is described that by using these two dopants and the host material in combination, the luminous efficiency of the organic electroluminescent element can be improved, and the driving voltage is reduced and the luminous lifetime is increased.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-108726

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2005-108727

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 2006-41395 Summary of the Invention

[0010] Technical Problem to be Solved by the Invention

[0011] However, the organic electroluminescent elements of Patent Document 1 and Patent Document 2 cannot sufficiently improve the light emission efficiency for the following reasons.

[0012] That is, in an organic electroluminescent element using a host material and a light-emitting dopant, when holes and electrons are injected into the light-emitting layer, the holes and electrons mainly recombine within the molecules of the host material to generate excitation energy, and thus the host material becomes an excited singlet state and an excited triplet state. The formation probabilities of excitons in the excited singlet state (singlet excitons) and excitons in the excited triplet state (triplet excitons) are statistically 25% for singlet excitons and 75% for triplet excitons.

[0013] Moreover, when the light-emitting dopant is a perylene derivative, an oxadiazole derivative, or an anthracene derivative exemplified in Patent Document 1 and Patent Document 2, the energy of the singlet excitons is transferred to the light-emitting dopant to excite the light-emitting dopant to an excited singlet state. The light-emitting dopant excited to the excited singlet state emits fluorescence when returning to the ground state thereafter. In contrast, the energy of the triplet excitons is not transferred to the light-emitting dopant, and thus the triplet excitons do not contribute to light emission and directly return to the ground state. Therefore, in this organic electroluminescent element, even if the probability of carrier recombination is increased by an auxiliary dopant, the energy of the triplet excitons, which accounts for 75% of the total excitons, is wasted, thus limiting the improvement of the light emission efficiency.

[0014] On the other hand, the organic electroluminescent element of Patent Document 3 uses a material such as an iridium organometallic complex that can convert triplet excitation energy into light emission as a first dopant. It is known that the iridium organometallic complex receives the excited triplet state energy from the host material through the effect of its heavy metal, and it is considered that in this system, the first dopant can also receive the energy of the host material and the second dopant in the excited triplet state and convert it into light emission. However, since the excited triplet state has a long lifetime, energy deactivation occurs due to saturation of the excited state or interaction with excitons in the excited triplet state, and generally the quantum yield of phosphorescence is not high. Therefore, it is difficult for the organic electroluminescent element of Patent Document 3 that mainly utilizes light emission (phosphorescence) from triplet excitation energy to sufficiently improve the light emission efficiency.

[0015] Therefore, the inventors considered these problems of the prior art and conducted in-depth research with the aim of providing an organic electroluminescent element with high light emission efficiency.

[0016] Means for Solving the Technical Problem

[0017] As a result of in-depth research, the present inventors have found that: as long as a delayed phosphor is used as an auxiliary dopant, the delayed phosphor in the excited triplet state undergoes reverse intersystem crossing to the excited singlet state. As a result, the triplet excitation energy can be converted into fluorescence, and thus an organic electroluminescent element having high luminous efficiency can be provided. Based on these findings, the present inventors provide the following invention as a method for solving the above problems.

[0018] [1] An organic electroluminescent element having an anode, a cathode, and at least one organic layer including a light-emitting layer between the anode and the cathode, wherein the organic electroluminescent element is characterized in that the light-emitting layer contains at least a first organic compound, a second organic compound, and a third organic compound satisfying the following formula (A), the second organic compound being a delayed phosphor, and the third organic compound being a light emitter.

[0019] Formula (A) E S1 (A) > E S1 (B) > E S1 (C)

[0020] (In the above formula, E S1 (A) represents the lowest excited singlet state energy level of the first organic compound, E S1 (B) represents the lowest excited singlet state energy level of the second organic compound, E S1 (C) represents the lowest excited singlet state energy level of the third organic compound.)

[0021] [2] The organic electroluminescent element according to [1], characterized in that the energy difference ΔE between the lowest excited singlet state of the second organic compound and the lowest excited triplet state at 77K st is 0.3 eV or less.

[0022] [3] The organic electroluminescent element according to [1], characterized in that the energy difference ΔE between the lowest excited singlet state of the second organic compound and the lowest excited triplet state at 77K st is 0.08 eV or less.

[0023] [4] The organic electroluminescent element according to any one of [1] to [3], characterized in that the first organic compound and the second organic compound satisfy the following formula (B).

[0024] Formula (B) E T1 (A) > E T1 (B)

[0025] (In the above formula, E T1 (A) represents the lowest excited triplet state energy level of the first organic compound at 77K, E T1(B) represents the lowest excited triplet energy level of the second organic compound at 77K.)

[0026] [5] The organic electroluminescent device according to any one of [1] to [4], wherein the third organic compound emits fluorescence when returning from the lowest excited singlet energy level to the ground state energy level.)

[0027] [6] The organic electroluminescent device according to any one of [1] to [5], wherein the content of the second organic compound in the light-emitting layer is less than the content of the first organic compound.)

[0028] [7] The organic electroluminescent device according to any one of [1] to [6], wherein the light-emitting layer contains two or more compounds as the third organic compound.)

[0029] [8] The organic electroluminescent device according to any one of [1] to [7], wherein the light-emitting layer contains one or two or more organic compounds in addition to the first organic compound, the second organic compound, and the third organic compound.)

[0030] [9] The organic electroluminescent device according to any one of [1] to [8], wherein the second organic compound is a compound represented by the following general formula (1).)

[0031] General formula (1)

[0032] (A)m-L-(D)n

[0033] [In general formula (1), L is an aromatic linking group with a valence of m + n, A is a group with a positive Hammett σp value or phenyl, D is a group with a negative Hammett σp value (excluding phenyl), m is an integer of 1 or more, and n is an integer of 2 or more. When m is 2 or more, multiple As may be the same or different. Two of the multiple Ds both contain a common aromatic ring, but are groups with different structures from each other.]

[0034]

[10] The organic electroluminescent device according to any one of [1] to [8], wherein the second organic compound is a compound represented by the following general formula (12).)

[0035] [Chemical formula 1]

[0036] General formula (12)

[0037]

[0038] [In general formula (12), R 11 ~R 15At least three of them are selected from a substituted or unsubstituted diarylamino group (wherein the two aryl groups constituting the diarylamino group may be bonded to each other) and a halogen atom, the selected groups are not all the same, and at least one is a substituted or unsubstituted diarylamino group (wherein the two aryl groups constituting the diarylamino group may be bonded to each other). The remaining 0 to 2 represent a hydrogen atom, a substituted or unsubstituted aryl group, or a cyano group.

[0039]

[11] The organic electroluminescent element according to any one of [1] to [8], wherein the second organic compound is a compound represented by the following general formula (14).

[0040] [Chemical formula 2]

[0041] General formula (14)

[0042]

[0043] [In general formula (14), R 11 , R 12 , R 14 , R 15 At least three of them are selected from a substituted or unsubstituted diarylamino group (wherein the two aryl groups constituting the diarylamino group may be bonded to each other) and a halogen atom, the selected groups are not all the same, and at least one is a substituted or unsubstituted diarylamino group (wherein the two aryl groups constituting the diarylamino group may be bonded to each other). The remaining 0 to 1 represent a hydrogen atom, a substituted or unsubstituted aryl group, or a cyano group.

[0044]

[12] A compound represented by the following general formula (13).

[0045] [Chemical formula 3]

[0046] General formula (13)

[0047]

[0048] [In general formula (13), at least three of R 11 to R 15 are a substituted or unsubstituted carbazol-9-yl group, and these at least three substituted or unsubstituted carbazol-9-yl groups are not all the same and are not substituted by a substituted or unsubstituted diarylamino group (wherein the two aryl groups constituting the diarylamino group may be bonded to each other). The remaining 0 to 2 represent a hydrogen atom, a substituted or unsubstituted aryl group, a halogen atom, or a cyano group.

[0049]

[13] A mixture, characterized in that it contains at least a first organic compound, a second organic compound, and a third organic compound that satisfy the following formula (A), wherein the second organic compound is a delayed phosphor and the third organic compound is a light emitter.

[0050] Formula (A) E S1 (A) > E S1 (B) > E S1 (C)

[0051] (In the above formula, E S1 (A) represents the lowest excited singlet state energy level of the first organic compound, E S1 (B) represents the lowest excited singlet state energy level of the second organic compound, E S1 (C) represents the lowest excited singlet state energy level of the third organic compound.)

[0052]

[14] A film, characterized in that it contains at least a first organic compound, a second organic compound, and a third organic compound that satisfy the following formula (A), wherein the second organic compound is a delayed phosphor and the third organic compound is a light emitter.

[0053] Advantages of the Invention

[0054] The organic electroluminescent device of the present invention combines three organic compounds that satisfy specific conditions, and thus has extremely high luminous efficiency. In particular, when the third organic compound is a compound that emits fluorescence when returning from the lowest excited singlet state energy level to the ground state energy level, the present invention can greatly improve the luminous efficiency. Description of the Drawings

[0055] Figure 1 is a schematic cross-sectional view showing an example of the layer structure of an organic electroluminescent device. Detailed Description of the Invention

[0056] The content of the present invention will be described in detail below. The description of the constituent elements described below is sometimes based on representative embodiments or specific examples of the present invention, but the present invention is not limited to such embodiments or specific examples. In addition, in the present specification, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. Moreover, the isotope species of the hydrogen atoms present in the molecules of the compounds used in the present invention are not particularly limited. For example, all of the hydrogen atoms in the molecule can be 1 H, or a part or all of them can be 2 H (deuterium D).

[0057] [Layer Structure of Organic Electroluminescent Device]

[0058] The organic electroluminescent element of the present invention has a structure including an anode, a cathode, and an organic layer formed between the anode and the cathode. The organic layer includes at least a light-emitting layer, and the light-emitting layer of the organic electroluminescent element of the present invention is characterized by its structure, which will be described in detail later.

[0059] The organic layer may consist only of a light-emitting layer, or may have one or more organic layers in addition to the light-emitting layer. Examples of such other organic layers include a hole transport layer, a hole injection layer, an electron blocking layer, a hole blocking layer, an electron injection layer, an electron transport layer, an exciton blocking layer, etc. The hole transport layer may be a hole injection and transport layer having a hole injection function, and the electron transport layer may be an electron injection and transport layer having an electron injection function. Structural examples of specific organic electroluminescent elements are illustrated in Figure 1 . In Figure 1 , 1 represents a substrate, 2 represents an anode, 3 represents a hole injection layer, 4 represents a hole transport layer, 5 represents a light-emitting layer, 6 represents an electron transport layer, and 7 represents a cathode.

[0060] The following describes each component and each layer of the organic electroluminescent element.

[0061] [Light-emitting layer]

[0062] The light-emitting layer is a layer that emits light after excitons are generated by the recombination of holes and electrons injected from the anode and the cathode, respectively.

[0063] In the organic electroluminescent element of the present invention, the light-emitting layer contains at least a first organic compound, a second organic compound, and a third organic compound that satisfy the following formula (A). The second organic compound is a delayed phosphor, and the third organic compound is a light-emitting body.

[0064] Formula (A) E S1 (A) > E S1 (B) > E S1 (C)

[0065] In the above formula, E S1 (A) represents the lowest excited singlet state energy level of the first organic compound, E S1 (B) represents the lowest excited singlet state energy level of the second organic compound, E S1 (C) represents the lowest excited singlet state energy level of the third organic compound.

[0066] Moreover, the "delayed phosphor" in the present invention refers to an organic compound that can reverse intersystem crossing to the excited singlet state after transitioning to the excited triplet state and can emit fluorescence when returning from the excited singlet state to the ground state. In addition, the lifetime of the light generated by the reverse intersystem crossing from the excited triplet state to the excited singlet state is longer than that of normal fluorescence (prompt fluorescence) or phosphorescence, and thus it is observed as fluorescence delayed compared to these. Therefore, this fluorescence is called "delayed fluorescence".

[0067] The lowest excited singlet state energies E of the first to third organic compounds in this light-emitting layer S1 (A), E S1 (B), E S1 (C) satisfy the above formula (A), and the second organic compound is a delayed phosphor, so that the excitation energy generated by the rebonding of holes and electrons injected into this light-emitting layer is efficiently converted into fluorescence, and high luminous efficiency can be obtained. This is considered for the following reasons.

[0068] That is, in this light-emitting layer, if excitation energy is generated by the rebonding of holes and electrons, each organic compound contained in the light-emitting layer transitions from the ground state to the excited singlet state and the excited triplet state. The formation probabilities of the organic compound in the excited singlet state (singlet exciton) and the organic compound in the excited triplet state (triplet exciton) are statistically 25% for singlet excitons and 75% for triplet excitons. Moreover, the energies of the first and second organic compounds in the excited singlet state among the excitons are transferred to the third organic compound, and the third organic compound in the ground state transitions to the excited singlet state. The third organic compound that becomes the excited singlet state emits fluorescence when returning to the ground state later.

[0069] At this time, in the organic electroluminescent element of the present invention, since the second organic compound is a delayed phosphor, the second organic compound in the excited triplet state reverse intersystem crosses to the excited singlet state, and the singlet excitation energy based on this reverse intersystem crossing also moves to the third organic compound. Therefore, the energy of the second organic compound with a large ratio in the excited triplet state also indirectly contributes to light emission, and compared with the structure in which the light-emitting layer does not contain the second organic compound, the luminous efficiency of the organic electroluminescent element can be dramatically improved.

[0070] In addition, in the organic electroluminescent element of the present invention, light emission is mainly generated by the third organic compound, but a part or a portion of the light emission can also be light emission from the first and second organic compounds. And this light emission includes both fluorescence emission and delayed fluorescence emission.

[0071] As long as the organic electroluminescent element of the present invention satisfies the above formula (A), and the second organic compound is a delayed phosphor and the third organic compound is a light emitter, there are no particular restrictions on the types and combinations of the first organic compound, the second organic compound, and the second organic compound. In terms of achieving higher luminous efficiency, the organic electroluminescent element of the present invention preferably further satisfies the following formula (B).

[0072] Formula (B) E T1 (A) > E T1 (B)

[0073] In the above formula, E T1 (A) represents the lowest excited triplet energy level of the first organic compound at 77K, and E T1 (B) represents the lowest excited triplet energy level of the second organic compound at 77K. The lowest excited triplet energy level E T1 (B) of the second organic compound and the lowest excited triplet energy level E T1 (C) of the third organic compound have no particular restrictions. For example, it can be selected as E T1 (B) > E T1 (C).

[0074] Hereinafter, the present invention will be further specifically described with reference to preferred specific examples, but the scope of the present invention should not be construed as being limited by the description based on the following specific examples.

[0075] First, the first compound, the second compound, and the third compound will be described in sequence, and other materials and elements will be described.

[0076] [First Organic Compound]

[0077] The first organic compound is an organic compound having a lowest excited singlet energy greater than that of the second organic compound and the third organic compound, and the first organic compound has a function as a host material responsible for transporting carriers or a function of enclosing the energy of the third organic compound in the compound. Thus, the third organic compound can efficiently convert the energy generated by the recombination of holes and electrons within the molecule and the energy received from the first organic compound and the second organic compound into light emission, thereby enabling an organic electroluminescent element with high luminous efficiency.

[0078] As the first organic compound, an organic compound having hole transport ability, electron transport ability, preventing the long-wavelength shift of light emission, and having a high glass transition temperature is preferred. The following are preferred compounds that can be used as the first organic compound. In addition, in the structural formulas of the following exemplified compounds, R represents a hydrogen atom or a substituent, and n represents an integer of 3 to 5.

[0079] [Chemical Formula 4]

[0080]

[0081] [Chemical Formula 5]

[0082]

[0083] [Chemical Formula 6]

[0084]

[0085] [Chemical Formula 7]

[0086]

[0087] [Chemical Formula 8]

[0088]

[0089] [Second Organic Compound]

[0090] In the present invention, as the second organic compound, a delayed phosphor capable of emitting delayed fluorescence is used. Among them, a thermally activated delayed phosphor that undergoes reverse intersystem crossing from the excited singlet state to the excited triplet state by absorbing thermal energy is preferably used. The thermally activated delayed phosphor absorbs the heat emitted by the device and relatively easily undergoes reverse intersystem crossing from the excited triplet state to the excited singlet state, so that the energy efficiency of its excited triplet state can contribute to luminescence well.

[0091] Moreover, the delayed phosphor used in the present invention preferably has an energy level E s1 in the lowest excited singlet state and an energy level E T1 in the lowest excited triplet state at 77K, and the difference ΔE st is 0.3 eV or less, more preferably 0.2 eV or less, further preferably 0.1 eV or less, and even more preferably 0.08 eV or less. The delayed phosphor with the energy difference ΔE st within the above range relatively easily causes reverse intersystem crossing from the excited triplet state to the excited singlet state, so that the energy efficiency of its excited triplet state can contribute to luminescence well.

[0092] There is no particular limitation on the delayed phosphor that can be used as the second organic compound.

[0093] As a specific group of compounds that can be used as the delayed phosphor of the second organic compound, the compounds represented by the following general formula (1) can be preferably selected.

[0094] General formula (1)

[0095] (A)m-L-(D)n

[0096] In general formula (1), L is an aromatic linking group having a valence of m + n, A is a group having a positive Hammett σp value or a phenyl group, D is a group having a negative Hammett σp value (excluding phenyl groups), m is an integer of 1 or more, and n is an integer of 2 or more. When m is 2 or more, the plurality of As may be the same or different from each other. Two of the plurality of Ds each contain a common aromatic ring, but are groups having different structures from each other.

[0097] In general formula (1), L is an aromatic linking group having a valence of m + n. m and n correspond to the number of As and the number of Ds bonded to the aromatic linking group, respectively. The aromatic linking group represented by L is composed of an aromatic ring. Among the positions of the aromatic ring that can be substituted by substituents, at m positions, A substitutes a hydrogen atom and bonds to a carbon atom, and at n positions, D substitutes a hydrogen atom and bonds to a carbon atom. That is, the aromatic linking group represented by L is composed of an aromatic ring excluding m + n hydrogen atoms. Among the positions of the aromatic ring that can be substituted by substituents, the positions substituted by A or D may be all or part of them, but it is preferred that all the positions of the aromatic ring that can be substituted are substituted by A or D.

[0098] The aromatic ring constituting the aromatic linking group represented by L may be an aromatic ring composed of hydrocarbons (hereinafter referred to as "aromatic hydrocarbon ring"), or may be an aromatic ring containing a heteroatom (hereinafter referred to as "aromatic heterocycle"). The group of the aromatic hydrocarbon ring that can be substituted by a substituent is methylene (-CH=). As the group of the aromatic heterocycle that can be substituted by a substituent, methylene (-CH=), imino (-NH-), etc. can be cited.

[0099] The aromatic hydrocarbon ring constituting the aromatic linking group represented by L may be a monocyclic ring, or may be a condensed ring formed by condensation of two or more aromatic hydrocarbon rings, or may be a spiro ring formed by spiro union of two aromatic hydrocarbon rings, or may be a linked ring formed by linking two or more aromatic hydrocarbon rings. When linking two or more aromatic hydrocarbon rings, they can be linked in a straight chain or in a branched chain. The number of carbon atoms of the aromatic hydrocarbon ring constituting the aromatic linking group is preferably 6 to 22, more preferably 6 to 18, further preferably 6 to 14, and still further preferably 6 to 10. Specific examples of the aromatic hydrocarbon ring constituting the aromatic linking group include a benzene ring, a naphthalene ring, a biphenyl ring, and a spirofluorene ring.

[0100] Moreover, the aromatic heterocycle constituting the aromatic linking group represented by L may be a monocyclic ring, a condensed ring formed by condensation of one or more heterocyclic rings with an aromatic hydrocarbon ring or an aromatic heterocyclic ring, a spiro ring formed by spiro-linking of one heterocyclic ring with an aromatic hydrocarbon ring or an aromatic heterocyclic ring, or a linking ring formed by linking of one or more aromatic heterocyclic rings with an aromatic hydrocarbon ring or an aromatic heterocyclic ring. The number of carbon atoms of the aromatic heterocycle is preferably 5 to 22, more preferably 5 to 18, further preferably 5 to 14, and still further preferably 5 to 10. The heteroatom constituting the aromatic heterocycle is preferably a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring, a pyridazine ring, a pyrimidine ring, a triazole ring, and a benzotriazole ring.

[0101] The aromatic ring constituting the aromatic linking group represented by L is more preferably a benzene ring.

[0102] A is a group with a positive Hammett σp value, and D is a group with a negative Hammett σp value. Among them, a phenyl group is exceptionally included in A but not in D.

[0103] Here, the "Hammett σp value" was proposed by L.P. Hammett to quantify the influence of a substituent on the reaction rate or equilibrium of a para-substituted benzene derivative. Specifically, it is the following formula established between the substituent in a para-substituted benzene derivative and the reaction rate constant or equilibrium constant:

[0104] log(k / k0) = ρσp

[0105] or

[0106] log(K / K0) = ρσp

[0107] The constant (σp) specific to the substituent in the above formula. In the above formula, k represents the rate constant of a benzene derivative without a substituent, k0 represents the rate constant of a benzene derivative substituted with a substituent, K represents the equilibrium constant of a benzene derivative without a substituent, K0 represents the equilibrium constant of a benzene derivative substituted with a substituent, and ρ represents the reaction constant determined by the type and conditions of the reaction. Regarding the description related to the "Hammett σp value" in the present invention and the numerical values of each substituent, reference can be made to the description related to the σp value in Hansch, C. et al., Chem. Rev., 91, 165 - 195 (1991). There is a tendency that a group with a negative Hammett σp value exhibits an electron-donating property (donor property), and a group with a positive Hammett σp value exhibits an electron-withdrawing property (acceptor property).

[0108] The aromatic linking group represented by L is bonded to m A's. When m is an integer of 1 or more and 2 or more, the plurality of A's may be the same or different from each other. The upper limit of m is not particularly limited, but is preferably less than n.

[0109] The group with a positive Hammett σp value represented by A is not particularly limited, but examples thereof include a cyano group, a group containing a carbonyl group or a sulfonyl group, or a substituted or unsubstituted heteroaryl group. As the heteroatom contained in the heteroaryl group, examples include a nitrogen atom, an oxygen atom, a sulfur atom, and a boron atom, and the heteroaryl group preferably contains at least one nitrogen atom as a ring member. As such a heteroaryl group, examples include a group composed of a 5-membered ring or a 6-membered ring containing a nitrogen atom as a ring member, or a group having a structure in which a benzene ring is fused with a 5-membered ring or a 6-membered ring containing a nitrogen atom as a ring member. Preferably, it is a monovalent group obtained by removing one hydrogen atom from a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, or a triazine ring, or a group having a structure in which these aromatic heterocycles are fused with each other, or a group having a structure in which a benzene ring is fused with these aromatic heterocycles. In addition, a monovalent group having a structure in which a benzene ring is fused with a quinone ring or a pyran ring and obtained by removing one hydrogen atom from the benzene ring is also more preferably a group with a positive Hammett σp value. Here, the benzene ring fused with the quinone ring or the pyran ring may be substituted with a substituent. As the substituent when the benzene ring fused with the quinone ring or the pyran ring has a substituent and the substituent when the heteroaryl group has a substituent, examples include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, a cyano group, a halogen atom, a heteroaryl group having 5 to 40 carbon atoms, and the like. The substituent capable of being substituted with a substituent among these substituents may be substituted. And, A contains a phenyl group. When m is 2 or more, the number of cyano groups in the plurality of A's can be, for example, 0 to 2, and one case is more preferable than two cases.

[0110] Hereinafter, specific examples of the group with a positive Hammett σp value represented by A are exemplified. Among them, in the present invention, the group with a positive Hammett σp value represented by A should not be construed as being limited to these groups. Regarding the group having a ring structure among the groups exemplified below, the hydrogen atom of any methylene (-CH=) constituting the ring structure is substituted with L and bonded to L. The lines on the left and right of CO of the carbonyl group (-CO-) and the lines on the left and right of SO2 of the sulfonyl group (-SO2-) each represent a single bond (connecting bond). The carbonyl group (-CO-) and the sulfonyl group (-SO2-) are directly bonded to L through a single bond or connected to L via a linking group, and the other single bond is bonded to an atomic group. As the atomic group, examples include a substituted or unsubstituted alkyl group, aryl group, heteroaryl group, etc. The number of carbon atoms of the alkyl group is preferably 1 to 20, the number of carbon atoms of the aryl group is preferably 6 to 40, and the number of carbon atoms of the heteroaryl group is preferably 5 to 40.

[0111] [Chemical formula 9]

[0112]

[0113] Next, D will be described.

[0114] The aromatic linking group represented by L is bonded to n Ds. n is an integer of 2 or more, and two of the multiple Ds both contain a common aromatic ring, but are groups having different structures from each other. The type of the common aromatic ring is not particularly limited, and it may be an aromatic hydrocarbon ring or an aromatic heterocyclic ring. Regarding the description and preferred range of the aromatic hydrocarbon ring and the aromatic heterocyclic ring, the corresponding parts of the description of the following conditions (a) and (b) can be referred to. As a preferred aromatic ring, a benzene ring can be cited, but it is not limited thereto. Further, as a group containing an aromatic ring, a group containing a diarylamine structure or a carbazole structure can be preferably exemplified, but it is not limited thereto. Two of the multiple Ds are both preferably groups having a heteroatom, and more preferably groups containing a nitrogen atom. As a specific structure, a group represented by any one of the following general formulas (2) to (9) can be cited.

[0115] Two of the multiple Ds preferably satisfy the following condition (a) or condition (b).

[0116] Condition (a)

[0117] Both of the two Ds have an aromatic ring containing an atom bonded to L, and between the two Ds, the aromatic ring is common, but at least one of the number of substituents substituted on the aromatic ring, the position on the aromatic ring substituted by the substituent, and the structure of the substituent substituted on the aromatic ring is different from each other.

[0118] Condition (b)

[0119] Both of the two Ds have a linking group bonded to L and one or more aromatic rings bonded to the linking group. When the aromatic ring bonded to the linking group in both of the two Ds is one, between the two Ds, the linking group and the aromatic ring bonded to the linking group are common, but at least one of the number of substituents substituted on the aromatic ring, the position on the aromatic ring substituted by the substituent, and the structure of the substituent substituted on the aromatic ring is different from each other. When the aromatic ring bonded to the linking group in both of the two Ds is two or more, between the two Ds, the linking group, the number of aromatic rings bonded to the linking group, and the multiple aromatic rings are common, respectively, but in at least one of the combinations of the mutually common aromatic rings between the two Ds, at least one of the number of substituents substituted on the aromatic ring, the position on the aromatic ring substituted by the substituent, and the structure of the substituent substituted on the aromatic ring is different from each other.

[0120] In the following description, one of the two Ds that satisfies condition (a) or condition (b) is referred to as "one D", and the other is referred to as "the other D". The two Ds ("one D" and "the other D") that satisfy condition (a) or condition (b) may be a group of the multiple Ds, or may be two or more groups.

[0121] Moreover, in condition (a), the "aromatic ring containing an atom bonded to L" possessed by one D is referred to as "one aromatic ring", and the "aromatic ring containing an atom bonded to L" possessed by the other D is referred to as "the other aromatic ring".

[0122] In condition (b), "when there are two or more aromatic rings bonded to the linking group in both of the two Ds, between the two Ds, the linking group, the number of aromatic rings bonded to the linking group, and the multiple aromatic rings are respectively common, but in at least one of the combinations of the mutually common aromatic rings between the two Ds, at least one of the number of substituents substituted on the aromatic ring, the position on the aromatic ring substituted by the substituent, and the structure of the substituent substituted on the aromatic ring is different from each other" means that, taking the case where a benzene ring and a naphthalene ring are linked to L via a trivalent linking group in one D as an example, similarly to one D, in the other D, the benzene ring and the naphthalene ring are also linked to L via the trivalent linking group L, and in the combinations of the mutually common aromatic rings, namely the combination of the benzene ring of one D and the benzene ring of the other D, or the combination of the naphthalene ring of one D and the naphthalene ring of the other D, or both of their combinations, at least one of the number of substituents substituted on the ring, the position on the ring substituted by the substituent, and the structure of the substituent substituted on the ring is different from each other. In condition (b), when there is one aromatic ring bonded to the linking group in both of the two Ds, the "aromatic ring linked to the linking group" possessed by one D is referred to as "one aromatic ring", and the "aromatic ring linked to the linking group" possessed by the other D is referred to as "the other aromatic ring". When there are two or more aromatic rings bonded to the linking group in both of the two Ds, one of the aromatic rings that is the "combination of the mutually common aromatic rings" between the two Ds and has at least one different substituent condition is referred to as "one aromatic ring", and the other is referred to as "the other aromatic ring".

[0123] Moreover, in the following description, the "number of substituents substituted on the aromatic ring", the "position on the aromatic ring substituted by the substituent", and the "structure of the substituent substituted on the aromatic ring" are sometimes collectively referred to as "substituent conditions".

[0124] The aromatic ring in condition (a) and condition (b) can be an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and can be a monocyclic ring or a condensed ring. When the aromatic ring forms a linking ring, the aromatic ring closest to the L side is the aromatic ring in condition (a) and condition (b). Aromatic rings being common means that between one aromatic ring and the other aromatic ring, all structures are the same except for the number of hydrogen atoms substituted by substituents and the substituent conditions.

[0125] The linking group in condition (b) can be a divalent linking group that links L to one aromatic ring, or a trivalent or higher-valent linking group that links L to two or more aromatic rings. When there are two or more aromatic rings bonded to the linking group, the aromatic rings bonded to the linking group can be the same as or different from each other.

[0126] The determination of the difference in the substituent conditions of the aromatic ring can be carried out in the following manner.

[0127] First, in one D and another D, compare the number of substituents of the common aromatic ring (including the common aromatic ring in the aromatic ring containing the atom bonded to L or the common aromatic ring in the aromatic ring connected to L via a linking group). When the number of substituents is different, it is determined that the "number of substituents substituted on the aromatic ring" in the above-mentioned substituent conditions is different. When the number of substituents is the same, compare the positions (substitution positions) on the aromatic ring substituted by the substituents. As long as there is one different substitution position, it is determined that the "position on the aromatic ring substituted by the substituents" in the above-mentioned substituent conditions is different. When all the substitution positions are the same, compare the structures of the substituents substituted on the aromatic ring. When at least one of the substituents substituted on the aromatic ring of one D is different from the structure of the substituent substituted at the corresponding substitution position of the aromatic ring of the other D, it is determined that the "structure of the substituents substituted on the aromatic ring" in the above-mentioned substituent conditions is different. Here, the "corresponding substitution position" of the aromatic ring of the other D is the position common to the substitution position of the aromatic ring of one D in the structural formula of the aromatic ring. Specifically, when the structural formulas and substitution positions of the aromatic rings of the two Ds are all aligned and overlapped, the overlapping positions correspond to each other as the "corresponding substitution positions". Or, the positions with the same position numbers of the aromatic ring marked according to the IUPAC nomenclature correspond to the "corresponding substitution positions". Among them, when the structural formula of the aromatic ring adopts a line-symmetric structure, the positions that overlap when rotated by 180° around the axis of symmetry are also included in the "corresponding substitution positions" for judgment. When at least one of the substituents substituted on the aromatic ring of one D is different from any one of the substituents substituted at the two corresponding substitution positions of the aromatic ring of the other D, it is determined that the "structure of the substituents substituted on the aromatic ring" is different. For example, regarding the substituent substituted at the 3-position of the carbazole ring, this corresponds to the case where the substituent substituted at the 3-position of another carbazole ring is different from the substituent substituted at the 6-position.

[0128] "The substituents have different structures" means that, for example, at least one of the following conditions is different: the type of the substituent, the types of atoms constituting the substituent and the number of each atom, the presence or position of a saturated bond, a chain structure (a straight-chain structure, a branched structure, and the position of the branch when it is a branched structure), and a ring structure (the number of ring members, an aromatic ring or a non-aromatic ring, and the presence or absence of a condensed ring). Further, when two substituents substituted on an aromatic ring are bonded to each other to form a ring structure, these two substituents can be regarded as "substituents" in the substituent conditions, respectively. For example, when the aromatic ring is a naphthalene ring, the naphthalene ring as a whole can be regarded as an "aromatic ring", or can be regarded as a benzene ring substituted with a substituent at adjacent positions. When the naphthalene ring is regarded as a benzene ring substituted with a substituent at adjacent positions, it has a relationship in which it is common for the unsubstituted benzene ring to be an aromatic ring and the number of substituents is different. In the present invention, even when the aromatic rings targeted between two Ds are in this relationship with each other, it is determined that condition (a) or condition (b) is satisfied.

[0129] Among these substituent conditions, "the number of substituents substituted on an aromatic ring" is preferably different between one aromatic ring and another aromatic ring, and the other aromatic ring is substituted with at least one substituent, and more preferably the other aromatic ring is unsubstituted.

[0130] Two Ds satisfying condition (a) or condition (b) preferably contain a diarylamine structure (wherein the two aryl groups constituting the diarylamine structure may be bonded to each other). The "diarylamine structure" in the present invention means a structure in which two aryl groups are bonded to a nitrogen atom, and the two aryl groups may be bonded to each other or may be substituted with a substituent. Regarding the preferred range and specific examples of the substituent when the aryl group has a substituent, reference can be made to R of the general formula (2) 11 ~R 19Preferred ranges and specific examples of substituents that can be used, etc. The aromatic hydrocarbon ring of the aryl group constituting the diarylamine structure may be a single ring or a condensed ring formed by condensation of two or more aromatic hydrocarbon rings. The number of carbon atoms of the aromatic hydrocarbon ring of the aryl group constituting the diarylamine structure is preferably 6 to 22, more preferably 6 to 18, further preferably 6 to 14, and still further preferably 6 to 10. Specific examples of the aryl group of the diarylamine structure include a substituted or unsubstituted phenyl group and a substituted or unsubstituted naphthyl group. Further, when the two aryl groups of the diarylamine structure are bonded to each other, the two aryl groups may be bonded by a single bond or may be connected via a linking group. Examples of the linking group connecting the two aryl groups include an oxygen atom, a sulfur atom, and a substituted or unsubstituted alkylene group. Examples of the substituent when the alkylene group has a substituent include a substituted or unsubstituted alkyl group and a substituted or unsubstituted aryl group. Specific examples of the diarylamine structure in which the two aryl groups are bonded to each other include a carbazole structure, a phenoxazine structure, a phenothiazine structure, and an acridine structure. The two Ds satisfying condition (a) or condition (b) more preferably include a carbazole structure.

[0131] In the group containing a diarylamine structure, the diarylamine structure may be bonded to L by a single bond or may be connected to L via a divalent linking group. The divalent linking group is not particularly limited. Regarding the diarylamine structure, any one hydrogen atom of the two aryl groups thereof may be substituted by L or a divalent linking group and bonded to L or the divalent linking group, or its nitrogen atom may be bonded to L or the divalent linking group. However, it is preferred that the nitrogen atom of the diarylamine structure is bonded to L or the divalent linking group, and more preferably the nitrogen atom of the diarylamine structure is directly bonded to L (bonded by a single bond). That is, the diarylamine structure is preferably a diarylamino group (wherein the two aryl groups constituting the diarylamine structure may be bonded to each other), and more preferably a diarylamino group bonded to L by a single bond.

[0132] Here, regarding the relationship between the diarylamine structure and condition (a) or condition (b), first, when the two aryl groups of the diarylamine structure are bonded to each other and one of the aryl groups or the nitrogen atom is bonded to L by a single bond, the whole diarylamine structure corresponds to the aromatic ring in condition (a).

[0133] When the two aryl groups of the diarylamine structure are bonded to each other and one of the aryl groups or the nitrogen atom is connected to L via a divalent linking group, the divalent linking group corresponds to the linking group in condition (b), and the whole diarylamine structure corresponds to the aromatic ring in condition (b).

[0134] When the two aryl groups of the diarylamine structure are not bonded to each other and one of the aryl groups is bonded to L by a single bond, the one aryl group bonded to L by a single bond corresponds to the aromatic ring of condition (a).

[0135] In the case where the two aryl groups in the diarylamine structure are not bonded to each other and the nitrogen atom thereof is bonded to L by a single bond, the nitrogen atom bonded to L by a single bond corresponds to the linking group of condition (b), and the two aryl groups correspond to the aromatic rings of condition (b).

[0136] In the case where the two aryl groups in the diarylamine structure are not bonded to each other and one of the aryl groups is linked to L by a divalent linking group, the divalent linking group corresponds to the linking group of condition (b), and one of the aryl groups bonded to the divalent linking group corresponds to the aromatic ring of condition (b).

[0137] In the case where the two aryl groups in the diarylamine structure are not bonded to each other and the nitrogen atom thereof is linked to L by a divalent linking group, the divalent linking group and the nitrogen atom correspond to the linking group of condition (b), and the two aryl groups correspond to the aromatic rings of condition (b).

[0138] The two Ds ( "one D" and "the other D") satisfying condition (a) are preferably groups represented by the following general formula (2).

[0139] [Chemical formula 10]

[0140] General formula (2)

[0141]

[0142] In general formula (2), R 11 ~R 19 each independently represents a hydrogen atom, a substituent, or a bonding position to L, and one of R 11 ~R 19 is a bonding position to L. The bonding position to L is preferably R 19 . The number of substituents is not particularly limited, and all of R 11 ~R 19 other than the bonding position to L may also be unsubstituted (hydrogen atom). When two or more of R 11 ~R 19 are substituents, the plurality of substituents may be the same as or different from each other. Among them, between the group represented by general formula (2) that becomes one D and the group represented by general formula (2) that becomes the other D, at least one condition among the number of substituents, the position of the substituents, and the structure of the substituents in R 11 ~R 19 is different from each other to satisfy condition (a).

[0143] For example, preferably, in one D, at least one of R 11 ~R 18 is a substituent, and in the other D, R 11 ~R18 The group corresponding to the group as a substituent in one D is a hydrogen atom. More preferably, in one D, R 13 and R 16 at least one of them is a substituent. In the other D, R 13 and R 16 the group corresponding to the group as a substituent in one D is a hydrogen atom. Moreover, in one D, it is further preferred that R 13 and R 16 these two are substituents. Even more preferably, R 13 and R 16 these two are substituted or unsubstituted aryl groups. In the other D, it is further preferred that R 11 ~R 18 are all hydrogen atoms.

[0144] Hereinafter, specific examples of the group represented by the general formula (2) are exemplified. Among them, the group represented by the general formula (2) that can be used in the present invention should not be construed as being limited by these specific examples. In the groups exemplified below, a single line extending from the benzene ring and not shown as a connecting group between other atoms represents a methyl group. Regarding the groups exemplified below, the hydrogen atoms bonded to the 1st to 9th positions of the carbazole ring are substituted by L and bonded to L. The bonding position of L in the carbazole ring is preferably the 9th position. As a combination of two Ds that satisfy the condition (a), for example, a combination of two groups selected from these groups can be adopted.

[0145] [Chemical formula 11-1]

[0146]

[0147] [Chemical formula 11-2]

[0148]

[0149] [Chemical formula 11-3]

[0150]

[0151] Two Ds ("one D" and "the other D") that satisfy the condition (a) or the condition (b) are also preferably groups represented by any one of the following general formulas (3) to (5).

[0152] [Chemical formula 12]

[0153] General formula (3)

[0154]

[0155] General formula (4)

[0156]

[0157] General formula (5)

[0158]

[0159] In general formulas (3) to (5), R 21 ~R 31 、R 41 ~R 53 、R 61 ~R 73 each independently represents a hydrogen atom, a substituent, or a bonding position to L, and one of R 21 ~R 31 , one of R 41 ~R 53 , and one of R 61 ~R 73 is respectively a bonding position to L. The bonding position to L is preferably R 31 、R 53 、R 73 . When one of R 21 ~R 30 , one of R 41 ~R 52 , and one of R 61 ~R 72 is a bonding position to L, the group represented by any one of general formulas (3) to (5) becomes the object of condition (a). When R 31 、R 53 、R 73 are bonding positions to L, the group represented by any one of general formulas (3) to (5) becomes the object of condition (b), the nitrogen atom corresponds to the linking group of condition (b), and the benzene ring and naphthalene ring bonded to the nitrogen atom correspond to the aromatic ring of condition (b). The number of substituents in general formulas (3) to (5) is not particularly limited, and all of R 21 ~R 31 、R 41 ~R 53 、R 61 ~R 67 、R 68 ~R 72 except for the bonding position to L can be unsubstituted (hydrogen atom). And, when there are two or more substituents in each of general formulas (3) to (5), these substituents can be the same or different from each other. Among them, between the group represented by any one of general formulas (3) to (5) that becomes one D and the group represented by any one of general formulas (3) to (5) that becomes another D, in R 21 ~R 31 、R 41 ~R53 and R 61 ~R 73 In at least any one of the groups, at least one condition among the number of substituents, the position of the substituents, and the structure of the substituents is different from each other to satisfy condition (a) or condition (b).

[0160] Hereinafter, specific examples of the group represented by any one of general formulas (3) to (5) are exemplified. Among them, the group represented by any one of general formulas (3) to (5) that can be used in the present invention should not be construed as being limited by these specific examples. In the groups exemplified below, a single line extending from the benzene ring and not shown as a linking group between other atoms represents a methyl group. Regarding the groups exemplified below, a hydrogen atom of any one of the methylene groups (-CH=) constituting the ring structure or a hydrogen atom bonded to a nitrogen atom is substituted by L and bonded to L. The bonding position of L in these groups is preferably a nitrogen atom. As a combination of two Ds that satisfy condition (a) or condition (b), for example, a combination of two groups selected from these groups can be adopted.

[0161] [Chemical formula 13-1]

[0162]

[0163] [Chemical formula 13-2]

[0164]

[0165] [Chemical formula 13-3]

[0166]

[0167] [Chemical formula 13-4]

[0168]

[0169] Two Ds ( "one D" and "the other D") that satisfy condition (a) or condition (b) are also preferably a group represented by the following general formula (6).

[0170] [Chemical formula 14]

[0171] General formula (6)

[0172]

[0173] In general formula (6), R 81 ~R 95 each independently represents a hydrogen atom, a substituent, or a bonding position with L, and one of R 81 ~R 95 is a bonding position with L. The bonding position with L is preferably R 83. In the group represented by the general formula (6), the benzene ring having the bonding position with L among the three benzene rings bonded to the nitrogen atom corresponds to the aromatic ring of condition (a). Alternatively, it is also possible to make the benzene ring having the bonding position with L and the nitrogen atom correspond to the linking group of condition (b), and make the remaining two benzene rings correspond to the aromatic rings of condition (b). The number of substituents is not particularly limited, and all of R 81 ~R 95 except for the bonding position with L may also be unsubstituted (hydrogen atom). And, when two or more of R 81 ~R 95 are substituents, the multiple substituents may be the same or different from each other. Among them, between the group represented by the general formula (6) that becomes one D and the group represented by the general formula (6) that becomes another D, in R 81 ~R 83 , R 86 ~R 90 and R 91 ~R 95 , at least one condition among the number of substituents, the position of substituents, and the structure of substituents is different from each other to satisfy condition (a) or condition (b).

[0174] Two Ds ("one D" and "another D") that satisfy condition (a) are also preferably groups represented by the following general formula (7).

[0175] [Chemical formula 15]

[0176] General formula (7)

[0177]

[0178] In the general formula (7), R 101 ~R 109 each independently represents a hydrogen atom, a substituent, or the bonding position with L, and one of R 101 ~R 109 is the bonding position with L. The bonding position with L is preferably R 109 . The number of substituents is not particularly limited, and all of R 101 ~R 109 except for the bonding position with L may also be unsubstituted (hydrogen atom). When two or more of R 101 ~R 109 are substituents, the multiple substituents may be the same or different from each other. Among them, between the group represented by the general formula (7) that becomes one D and the group represented by the general formula (7) that becomes another D, R 101 ~R 109At least one of the number of substituents, the position of the substituents, and the structure of the substituents is different from each other to satisfy condition (a).

[0179] Two Ds ("one D" and "the other D") that satisfy condition (a) are also preferably groups represented by the following general formula (8).

[0180] [Chemical formula 16]

[0181] General formula (8)

[0182]

[0183] In general formula (8), R 111 ~R 119 each independently represents a hydrogen atom, a substituent, or a bonding position to L, and one of R 111 ~R 119 is a bonding position to L. The bonding position to L is preferably R 119 . There is no particular limitation on the number of substituents, and all of R 111 ~R 119 except for the bonding position to L may also be unsubstituted (hydrogen atom). When two or more of R 111 ~R 119 are substituents, the plurality of substituents may be the same or different from each other. Among them, between the group represented by general formula (8) that becomes one D and the group represented by general formula (8) that becomes the other D, at least one of the number of substituents, the position of the substituents, and the structure of the substituents in R 111 ~R 119 is different from each other to satisfy condition (a).

[0184] Two Ds ("one D" and "the other D") that satisfy condition (a) are also preferably groups represented by the following general formula (9).

[0185] [Chemical formula 17]

[0186] General formula (9)

[0187]

[0188] In general formula (9), R 121 ~R 131 each independently represents a hydrogen atom, a substituent, or a bonding position to L, and one of R 121 ~R 131 is a bonding position to L. The bonding position to L is preferably R 131 . There is no particular limitation on the number of substituents, and R 121 ~R 131All except the bonding position with L may also be unsubstituted (hydrogen atom). In R 121 ~R 131 When two or more of them are substituents, the multiple substituents may be the same as or different from each other. Among them, between the group represented by the general formula (9) as one D and the group represented by the general formula (9) as the other D, R 121 ~R 131 At least one of the number of substituents, the position of the substituents, and the structure of the substituents is different from each other to satisfy the condition (a).

[0189] As R 11 ~R 19 of the general formula (2), R 21 ~R 31 of the general formula (3), R 41 ~R 53 of the general formula (4), R 61 ~R 73 of the general formula (5), R 81 ~R 95 of the general formula (6), R 101 ~R 109 of the general formula (7), R 111 ~R 119 of the general formula (8), and R 121 ~R 131 of the general formula (9), the substituents that can be adopted include, for example, a hydroxyl group, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylthio group having 1 to 20 carbon atoms, an alkyl-substituted amino group having 1 to 20 carbon atoms, an acyl group having 2 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, a heteroaryl group having 3 to 40 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, an alkylsulfonyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, an amide group, an alkylamide group having 2 to 10 carbon atoms, a trialkylsilyl group having 3 to 20 carbon atoms, a trialkylsilylalkyl group having 4 to 20 carbon atoms, a trialkylsilylalkenyl group having 5 to 20 carbon atoms, a trialkylsilylalkynyl group having 5 to 20 carbon atoms, and a nitro group, etc. In these specific examples, the groups that can be further substituted by substituents can be substituted by the substituents of these specific examples. More preferred substituents are a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, a substituted or unsubstituted diarylamino group having 1 to 20 carbon atoms, a substituted or unsubstituted carbazolyl group.

[0190] The remaining groups in D, other than the groups that satisfy condition (a) or condition (b), only need to be groups with a negative Hammett σp value, and there are no particular restrictions other than this. However, it is preferably a group containing a diarylamine structure (wherein the two aryl groups constituting the diarylamine structure may be bonded to each other), more preferably a group containing a diarylamino group (wherein the two aryl groups constituting the diarylamino group may be bonded to each other), and further preferably a group represented by the general formula (2) to (9). Regarding the description, preferred range, and specific examples of these structures and groups, reference can be made to the description, preferred range, and specific examples of the diarylamine structure, diarylamino group, and groups represented by the general formula (2) to (9) in the two Ds that satisfy condition (a) or condition (b). Among them, in these references, the descriptions related to condition (a) or condition (b) are not included in the reference content.

[0191] The compound represented by the general formula (1) is preferably a compound represented by the following general formula (10).

[0192] [Chemical formula 18]

[0193] General formula (10)

[0194]

[0195] In the general formula (10), A 1 represents a group with a positive Hammett σp value. R 1 ~R 5 each independently represents a hydrogen atom, a group with a positive Hammett σp value, or a group with a negative Hammett σp value, and at least two of R 1 ~R 5 are groups with a negative Hammett σp value (excluding phenyl). When one or more of R 1 ~R 6 are groups with a positive Hammett σp value, the group with a positive Hammett σp value represented by A 1 and the groups with a positive Hammett σp value among R 1 ~R 6 may be the same or different from each other.

[0196] R 1 ~R 5 Among the groups with a negative Hammett σp value, two of them preferably satisfy the following condition (a) or condition (b).

[0197] Condition (a)

[0198] Both of the two groups with negative Hammett σp values have an aromatic ring containing an atom bonded to L. Between the two groups with negative Hammett σp values, the aromatic ring is common, but at least one of the number of substituents substituted on the aromatic ring, the position of the aromatic ring substituted by the substituent, and the structure of the substituent substituted on the aromatic ring is different from each other.

[0199] Condition (b)

[0200] Both of the two groups with negative Hammett σp values have a linking group bonded to L and one or more aromatic rings bonded to the linking group. When the number of aromatic rings bonded to the linking group is one in both of the two groups with negative Hammett σp values, between the two groups with negative Hammett σp values, the linking group and the aromatic ring bonded to the linking group are common, but at least one of the number of substituents substituted on the aromatic ring, the position of the aromatic ring substituted by the substituent, and the structure of the substituent substituted on the aromatic ring is different from each other. When the number of aromatic rings bonded to the linking group is two or more in both of the two groups with negative Hammett σp values, between the two groups with negative Hammett σp values, the linking group, the number of aromatic rings bonded to the linking group, and the plurality of aromatic rings are common, respectively, but in at least one of the combinations of the mutually common aromatic rings between the two groups with negative Hammett σp values, at least one of the number of substituents substituted on the aromatic ring, the position of the aromatic ring substituted by the substituent, and the structure of the substituent substituted on the aromatic ring is different from each other.

[0201] Regarding A 1 , R 1 ~R 5 For the group with a positive Hammett σp value represented by, R 1 ~R 5 For the group with a negative Hammett σp value represented by and R 1 ~R 5 For the explanations of two of the groups with negative Hammett σp values in R

[0202] R 1 ~R 5 The number of groups with a positive Hammett σp value in R is preferably 0 to 3, more preferably 0 to 2, still more preferably 0 or 1, and most preferably 0. R 1 ~R 5The number of groups with a negative Hammett σp value in it is preferably 2 to 5, more preferably 3 to 5, still more preferably 4 or 5, and most preferably 5. In R 1 ~R 5 , the combination of two groups satisfying condition (a) or condition (b) can be one or two. And the combination of two groups satisfying condition (a) or condition (b) is preferably a combination at positions that are point-symmetric to each other on the benzene ring in the general formula (1). That is, the combination of R 1 and R 4 and the combination of R 2 and R 5 in one or both preferably satisfy condition (a) or condition (b).

[0203] The compound represented by the general formula (1) is also preferably a compound represented by the following general formula (11).

[0204] [Chemical formula 19]

[0205] General formula (11)

[0206]

[0207] In the general formula (11), A X1 represents a group with a positive Hammett σp value. R X11 ~R X14 each independently represents a hydrogen atom, a group with a positive Hammett σp value, or a group with a negative Hammett σp value, and at least two of R X11 ~R X14 are groups with a negative Hammett σp value (excluding phenyl). When one or more of R X11 ~R X14 are groups with a positive Hammett σp value, the group with a positive Hammett σp value represented by A X1 and the groups with a positive Hammett σp value among R X11 ~R X14 can be the same or different from each other.

[0208] R X11 ~R X14 Among the groups with a negative Hammett σp value, two preferably satisfy the above condition (a) or condition (b).

[0209] Regarding A 1 、R X11 ~R X14 The groups with a positive Hammett σp value represented by, R X11 ~R X14 The groups with a negative Hammett σp value represented by, and R X11 ~R X14The descriptions of two of the groups with a negative Hammett σp value in , the preferred ranges, specific examples, and the descriptions of conditions (a) and (b) can be respectively referred to the groups with a positive Hammett σp value represented by A in the general formula (1), the groups with a negative Hammett σp value represented by D, the description and preferred range of two of the multiple Ds, specific examples, and the descriptions of conditions (a) and (b).

[0210] R X11 ~R X14 The number of groups with a positive Hammett σp value in is preferably 0 to 2, more preferably 0 or 1, and most preferably 0. R X11 ~R X14 The number of groups with a negative Hammett σp value in is preferably 2 to 4, more preferably 3 or 4, and further preferably 4. In R X11 ~R X14 The combination of two groups that satisfy condition (a) or condition (b) can be one or two.

[0211] The second organic compound is also preferably a compound represented by the following general formula (12). As long as the compound represented by the general formula (12) is used as the second organic compound to fabricate an organic electroluminescent element, the luminous efficiency and lifespan are improved.

[0212] [Chemical formula 20]

[0213] General formula (12)

[0214]

[0215] In the general formula (12), R 11 ~R 15 At least three of are selected from substituted or unsubstituted diarylamino groups (wherein the two aryl groups constituting the diarylamino group may be bonded to each other) and halogen atoms. The selected groups are not all the same, and at least one is a substituted or unsubstituted diarylamino group (wherein the two aryl groups constituting the diarylamino group may be bonded to each other). The remaining 0 to 2 represent hydrogen atoms, substituted or unsubstituted aryl groups, or cyano groups.

[0216] For example, at least three of R 11 ~R 15 can be substituted or unsubstituted diarylamino groups, and there may be no halogen atoms in R 11 ~R 15 At this time, the substituted or unsubstituted diarylamino groups present in the molecule are not all the same. And, at least two of R 11 ~R 15 can be substituted or unsubstituted diarylamino groups, and R 11 ~R15 At least one of them may be a halogen atom. At this time, the substituted or unsubstituted diarylamino groups present in the molecule may be all the same or different. And, R 11 ~R 15 At least one of them may be a substituted or unsubstituted diarylamino group, and at least two of R 11 ~R 15 may be halogen atoms. At this time, the halogen atoms present in the molecule may be all the same or different.

[0217] Regarding the description and preferred range of the diarylamino group that can be adopted for R 11 ~R 15 , the description and preferred range of the diarylamine structure that can be adopted for two Ds satisfying the above condition (a) or condition (b) can be referred to. And, regarding the specific structure, the descriptions in the above general formulas (2) to (5), general formulas (7) to (9) can be referred to. Here, R 19 in general formula (2), R 31 in general formula (3), R 41 in general formula (4), R 73 in general formula (5), R 109 in general formula (7), R 119 in general formula (8), R 131 in general formula (9) become the bonding positions. Among them, R 11 ~R 15 The diarylamino group that can be adopted is preferably the group represented by general formula (2) (R 19 is the bonding position).

[0218] As the substituents of the two aryl groups that can substitute the diarylamino group constituting R 11 ~R 15 , preferably selected are substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, substituted or unsubstituted diarylamino groups, substituted or unsubstituted diheteroarylamino groups, substituted or unsubstituted arylheteroarylamino groups, substituted or unsubstituted alkyl groups, substituted or unsubstituted alkoxy groups or substituted or unsubstituted aryloxy groups. These groups may be further substituted by these substituents.

[0219] As R 11 ~R 15Specific examples of the substituted diarylamino group that can be used include 3-methylcarbazol-9-yl, 3,6-dimethylcarbazol-9-yl, 3-ethylcarbazol-9-yl, 3,6-diethylcarbazol-9-yl, 3-tert-butylcarbazol-9-yl, 3,6-di-tert-butylcarbazol-9-yl, 3-phenylcarbazol-9-yl, 3,6-diphenylcarbazol-9-yl, 3-(carbazol-9-yl)carbazol-9-yl, 3,6-bis(carbazol-9-yl)carbazol-9-yl, and the like.

[0220] When R 11 ~R 15 is a substituted or unsubstituted carbazol-9-yl group, in terms of the luminous efficiency or lifespan of the organic electroluminescent element, these substituted or unsubstituted carbazol-9-yl groups are preferably not substituted with a substituted or unsubstituted diarylamino group. As substituents of the carbazol-9-yl group, preferred are a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted diarylamino group, a substituted or unsubstituted diheteroarylamino group, a substituted or unsubstituted arylheteroarylamino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryloxy group.

[0221] When there are two or more substituted or unsubstituted diarylamino groups in the molecule and they are different from each other, the types of substituted or unsubstituted diarylamino groups present in the molecule are preferably two or three, more preferably two. For example, when three of R 11 ~R 15 are substituted or unsubstituted diarylamino groups, the case where two are the same and one is different is preferred. For example, the case where R 11 and R 15 are the same and R 12 is different, the case where R 11 and R 14 are the same and R 12 is different, the case where R 11 and R 14 are the same and R 15 is different, the case where R 12 and R 14 are the same and R 11 is different can be cited. For example, when four of R 11 ~R 15 are substituted or unsubstituted diarylamino groups, the case where three are the same and one is different or the case where two are the same and the other two are also the same is preferred. For example, the case where R 11 and R 15 are the same and R 12 and R 14 are the same, the case where R 11 and R 12Same and R 14 and R 15 Same situation, R 11 and R 14 Same and R 12 and R 15 Same situation, R 12 and R 14 and R 15 Same but only R 11 Different situation, R 11 and R 14 and R 15 Same but only R 12 Different situation. When all of R 11 ~R 15 are substituted or unsubstituted diarylamino groups, preferably there are four same and one different situation or three same and two different situations. For example, it can be cited that R 11 and R 13 and R 15 are the same and R 12 and R 14 are the same situation, R 11 and R 12 and R 13 are the same and R 14 and R 15 are the same situation, R 12 and R 13 and R 14 are the same and R 11 and R 15 are the same situation, R 11 and R 12 and R 14 are the same and R 13 and R 15 are the same situation.

[0222] When there are two or more substituted or unsubstituted diarylamino groups in the molecule, the differences can be the difference in whether the diarylamino group has a substituent or not, the difference in the type of the substituent bonded to the diarylamino group, or the difference in the bonding position of the substituent bonded to the diarylamino group. Preferably, it is the difference in whether the diarylamino group has a substituent or not and the difference in the type of the substituent bonded to the diarylamino group. As an example of the difference in the type of the substituent bonded to the diarylamino group, the way in which a carbazol-9-yl substituted with an alkyl group and a carbazol-9-yl substituted with an aryl group exist in the molecule can be cited. As an example of the difference in the bonding position of the substituent bonded to the diarylamino group, the way in which a carbazol-9-yl substituted with an alkyl group at the 3-position and a 6-position and a carbazol-9-yl substituted with an alkyl group only at the 3-position exist in the molecule can be cited.

[0223] R 11~R 15 The halogen atom that can be used may be any one of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, but is preferably a fluorine atom.

[0224] R 11 ~R 15 The remaining 0 to 2 of ~R represent a hydrogen atom, a substituted or unsubstituted aryl group, or a cyano group. It is preferably a substituted or unsubstituted aryl group or a cyano group. In the case where ~R 11 ~R 15 remains (that is, in the case where the remainder is one or two), it may be any one of ~R 11 ~R 15 but preferably contains at least one of 12 R 13 R 14 and is preferably one or two of 12 R 13 R 14 and more preferably contains at least 13 R 11 ~R 15 For the description and preferred range of the remaining aryl group that can be adopted for ~R, reference can be made to the description and preferred range of the aryl group of the diarylamine structure that can be adopted for two Ds satisfying the above condition (a) or condition (b). The remaining aryl group that can be adopted for ~R 11 ~R 15 can be substituted, and an alkyl group or an aryl group is preferably used as a substituent. As the remaining aryl group that can be adopted for ~R 11 ~R 15 for example, a phenyl group substituted with an alkyl group or an aryl group at the 4-position, or a phenyl group substituted with an alkyl group or an aryl group at the 3-position and 5-position can be cited.

[0225] As an example of a preferred compound group in the compound represented by the general formula (12), there can be cited a compound group in which at least three of 11 ~R 15 are substituted or unsubstituted diarylamino groups and no halogen atom exists in 11 ~R 15 .

[0226] As an example of a preferred compound group in the compound represented by the general formula (12), there can be cited a compound group in which 11 ~R 15A group of compounds in which at least three of them are substituted or unsubstituted carbazol-9-yl groups. Among them, as a more preferred group of compounds, a group of compounds can be cited in which any one of the carbazol-9-yl groups present in the molecule is not substituted by a substituted or unsubstituted diarylamino group (wherein the two aryl groups constituting the diarylamino group may be bonded to each other, and for example, it also includes a carbazol-9-yl group). Compared with compounds having a carbazol-9-yl group substituted by a substituted or unsubstituted diarylamino group, it is more preferred in terms of luminous efficiency or lifespan. As a group of such compounds, a group of compounds represented by the following general formula (13) can be cited.

[0227] [Chemical formula 21]

[0228] Covered formula (13)

[0229]

[0230] In general formula (13), R 11 ~R 15 Among them, at least three are substituted or unsubstituted carbazol-9-yl groups, and these at least three substituted or unsubstituted carbazol-9-yl groups are not all the same, and are not substituted by a substituted or unsubstituted diarylamino group (wherein the two aryl groups constituting the diarylamino group may be bonded to each other). The remaining 0 to 2 represent a hydrogen atom, a substituted or unsubstituted aryl group, a halogen atom, or a cyano group.

[0231] Among the compounds represented by general formula (13), for example, a group of compounds in which the remaining 0 to 2 are a substituted or unsubstituted aryl group or a cyano group can be selected, and a group of compounds in which the remaining 0 to 2 are a substituted or unsubstituted aryl group can be further selected.

[0232] Among the compounds represented by general formula (13), for example, a group of compounds in which R 13 is a hydrogen atom, a substituted or unsubstituted aryl group, a halogen atom, or a cyano group, or a group of compounds in which R 13 is a hydrogen atom, a substituted or unsubstituted aryl group or a cyano group, or a group of compounds in which R 13 is a substituted or unsubstituted aryl group or a cyano group, or a group of compounds in which R 13 is a substituted or unsubstituted aryl group can be selected.

[0233] Among the compounds represented by general formula (13), a group of compounds in which at least three of R 11 ~R 15 represent a substituted carbazol-9-yl group and at least any one of the substituents (substituents of the substituted carbazol-9-yl group) is different can be selected.

[0234] Among the compounds represented by general formula (13), a group of compounds in which R 11~R 15 At least one of them is a substituted carbazol-9-yl, and R 11 ~R 15 A group of compounds in which at least one of them is an unsubstituted carbazol-9-yl.

[0235] Among the compounds represented by the general formula (13), it is also possible to select the group of compounds where R 11 and R 15 are the same, the group of compounds where R 12 and R 14 are the same, the group of compounds where R 11 and R 12 and R 15 are the same, the group of compounds where R 11 and R 12 and R 14 are the same.

[0236] The second organic compound is also preferably a compound represented by the following general formula (14).

[0237] [Chemical formula 22]

[0238] General formula (14)

[0239]

[0240] In the general formula (14), at least three of R 11 , R 12 , R 14 , R 15 are selected from substituted or unsubstituted diarylamino (wherein the two aryl groups constituting the diarylamino may be bonded to each other) and halogen atoms, the selected groups are not all the same, and at least one is substituted or unsubstituted diarylamino (wherein the two aryl groups constituting the diarylamino may be bonded to each other). The remaining 0 to 1 represents a hydrogen atom, a substituted or unsubstituted aryl group, or a cyano group.

[0241] Regarding the description and preferred range of R 11 , R 12 , R 14 , R 15 in the general formula (14), reference can be made to the corresponding description of the general formula (12).

[0242] As another specific group of compounds that can be used as the delayed phosphor of the second organic compound, for example, a group of compounds represented by the following general formula can be cited.

[0243] [Chemical formula 23]

[0244] General formula (15)

[0245]

[0246] In general formula (15), R 1 and R 2 each independently represent a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted cycloalkyl group, R 5 and R 6 each independently represent a substituted or unsubstituted alkyl group, R 7 , R 8 and R 9 each independently represent a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted carbazolyl group, R 10 represents a carbazolyl group, which may be substituted by a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted cycloalkyl group, n1, n2, n6, and n7 each independently represent any integer from 0 to 4, n5 represents any integer from 0 to 3, n8 and n9 each independently represent any integer from 0 to 5. n10 represents 0 or 1. When n1, n2, and n5 to n9 are integers of 2 or more, a plurality of R 1 , R 2 and R 5 to R 9 may be the same as or different from each other.

[0247] For the detailed description, preferred range, and specific compound examples of general formula (15), reference can be made to the relevant descriptions in WO2014 / 051184, which is incorporated herein by reference as part of this specification.

[0248] As another specific compound group that can be used as the second organic compound of the delayed phosphor, for example, a compound group represented by the following general formula can be cited.

[0249] [Chemical formula 24]

[0250] General formula (16)

[0251] D - A - D

[0252] In general formula (16), A has the following general formulas (2 - a) to (5 - a):

[0253] [Chemical formula 25]

[0254] General formula (2 - a)

[0255]

[0256] General formula (3-a)

[0257]

[0258] General formula (4-a)

[0259]

[0260] General formula (5-a)

[0261]

[0262] A divalent group represented by any one of the following (wherein the hydrogen atoms in the structures of general formulas (2-a) to (5-a) may be substituted by substituents), and two Ds each independently represent a group having a structure selected from the following group:

[0263] [Chemical formula 26]

[0264]

[0265] A group having a structure (wherein the hydrogen atoms in the structure may be substituted by substituents).

[0266] Regarding the detailed description, preferred range, and specific compound examples of general formula (16), reference can be made to the relevant descriptions in WO2014 / 126200, which is incorporated herein by reference as part of this specification.

[0267] As another specific compound group that can be used as the second organic compound's delayed phosphor, for example, a compound group represented by the following general formula can be cited.

[0268] [Chemical formula 27]

[0269] General formula (17)

[0270]

[0271] In general formula (17), R 1 , R 3 and R 5 represent cyano or R 1 , R 2 , R 4 and R 5 represent cyano, and the remaining R 1 ~R 6 each independently represent a group represented by any one of the following general formulas (2-b) to (8-b).

[0272] [Chemical formula 28-1]

[0273] General formula (2-b)

[0274]

[0275] General formula (3-b)

[0276]

[0277] General formula (4-b)

[0278]

[0279] [Chemical formula 28-2]

[0280] General formula (5-b)

[0281]

[0282] General formula (6-b)

[0283]

[0284] General formula (7-b)

[0285]

[0286] General formula (8-b)

[0287]

[0288] In general formulas (2-b) to (8-b), L 12 ~L 18 represents a single bond or a substituted or unsubstituted arylene group, and * represents the bonding site to the benzene ring in general formula (1). R 11 ~R 20 , R 21 ~R 28 , R 31 ~R 38 , R 3a , R 3b , R 41 ~R 48 , R 4a , R 51 ~R 58 , R 61 ~R 68 , R 71 ~R 78 each independently represents a hydrogen atom or a substituent. R 11 and R 12 , R 12 and R 13 , R 13 and R 14 , R 14 and R 15 , R 16 and R17 , R 17 and R 18 , R 18 and R 19 , R 19 and R 20 , R 21 and R 22 , R 22 and R 23 , R 23 and R 24 , R 24 and R 25 , R 25 and R 26 , R 26 and R 27 , R 27 and R 28 , R 31 and R 32 , R 32 and R 33 , R 33 and R 34 , R 35 and R 36 , R 36 and R 37 , R 37 and R 38 , R 3a and R 3b , R 41 and R 42 , R 42 and R 43 , R 43 and R 44 , R 45 and R 46 , R 46 and R 47 , R 47 and R 48 , R 51 and R 52 , R 52 and R 53 , R 53 and R 54 , R 55 and R 56 , R 56 and R 57 , R 57 and R 58 , R 61 and R 62 , R 62 and R 63 , R 63 and R 64 , R 65 and R 66, R 66 and R 67 , R 67 and R 68 , R 71 and R 72 , R 72 and R 73 , R 73 and R 74 , R 75 and R 76 , R 76 and R 77 , R 77 and R 78 can bond to each other to form a cyclic structure, respectively.

[0289] For the detailed description, preferred range, and specific compound examples of the general formula (17), reference can be made to the relevant descriptions in WO2015 / 129715, which is incorporated herein by reference as part of this specification.

[0290] As another specific group of compounds that can be used as the delayed phosphor of the second organic compound, for example, a group of compounds represented by the following general formula can be cited.

[0291] [Chemical formula 29]

[0292] General formula (18)

[0293]

[0294] In the general formula (18), Ar 1 ~Ar 3 each independently represents a substituted or unsubstituted aryl group, and at least one of Ar 1 ~Ar 3 is a carbazolyl group substituted at the N-position with a group containing an electron-withdrawing group.

[0295] For the detailed description, preferred range, and specific compound examples of the general formula (18), reference can be made to the relevant descriptions in WO2015 / 133501, which is incorporated herein by reference as part of this specification.

[0296] As another specific group of compounds that can be used as the delayed phosphor of the second organic compound, for example, a group of compounds represented by the following general formula can be cited.

[0297] [Chemical formula 30]

[0298] General formula (19)

[0299]

[0300] In general formula (19), m and n are each independently an integer of 1 to 3, and m + n is 2 to 4; A is a substituted heteroaryl group having an electron-donating property, and at least one of the substituents on the aromatic heterocycle is an electron-withdrawing group; when m is 2 or more, each A may be the same or different.

[0301] For the detailed description, preferred range, and specific compound examples of general formula (19), reference can be made to the relevant descriptions in WO2015 / 137136 incorporated herein by reference as part of this specification.

[0302] As another specific group of compounds that can be used as the second organic compound, a delayed phosphor, for example, a group of compounds represented by the following general formula can be cited.

[0303] [Chemical formula 31]

[0304] General formula (20)

[0305]

[0306] In general formula (20), ring A represents an aromatic ring represented by formula (1A) that is condensed with an adjacent ring at an arbitrary position, and ring B represents a heterocycle represented by formula (1B) that is condensed with an adjacent ring at an arbitrary position. Ar in formula (1) and (1B) independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group. R in formula (1) and (1A) is independently hydrogen or a monovalent substituent, and adjacent substituents may combine to form a ring. n represents an integer of 1 or more and 4 or less.

[0307] [Chemical formula 32]

[0308]

[0309] For the detailed description, preferred range, and specific compound examples of general formula (20), reference can be made to the relevant descriptions in Japanese Patent Publication No. 5124785 incorporated herein by reference as part of this specification.

[0310] As another specific group of compounds that can be used as the second organic compound, a delayed phosphor, for example, a group of compounds represented by the following general formula can be cited.

[0311] [Chemical formula 33]

[0312] General formula (21)

[0313]

[0314] In general formula (21), R 1 ~R 5 each independently represents a hydrogen atom or a substituent, and R 1 ~R5 One of them represents a cyano group, R 1 ~R 5 One to three of them represent an aryl group Ar which may be substituted by an alkyl group or an aryl group (wherein, in the benzene ring constituting the latter aryl group, a ring containing an oxygen atom or a sulfur atom as a ring skeleton constituting atom in addition to a carbon atom may be condensed, but a ring containing a heteroatom other than an oxygen atom and a sulfur atom as a ring skeleton constituting atom will not be condensed). Among R 1 ~R 5 When two or more of them are Ar, these Ar may be the same as or different from each other. R 1 ~R 5 One to three of them represent a donor group D (excluding the group corresponding to Ar). Among R 1 ~R 5 When two or more of them are D, these D may be the same as or different from each other.

[0315] Preferably, R 1 ~R 5 in the general formula (21) are each independently a cyano group, Ar or D; preferably, D contains a substituted amino group; preferably, D is a group represented by the following general formula (2c);

[0316] [Chemical formula 34]

[0317] General formula (2c)

[0318]

[0319] In the general formula (2c), R 11 and R 12 each independently represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. L represents a single bond, a substituted or unsubstituted arylene group or a substituted or unsubstituted heteroarylene group, and * represents the bonding position to the carbon atom (C) of the ring skeleton constituting the benzene ring in the general formula (1). R 11 and R 12 may bond to each other to form a cyclic structure.

[0320] Preferably, D is a group represented by the following general formula (3c);

[0321] [Chemical formula 35]

[0322] General formula (3c)

[0323]

[0324] [In the general formula (3c), R 21 ~R 28Each independently represents a hydrogen atom or a substituent. L represents a single bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group, R 21 and R 22 、R 22 and R 23 、R 23 and R 24 、R 24 and R 25 、R 26 and R 27 、R 27 and R 28 may be bonded to each other to form a linking group required for forming a cyclic structure. And, R 25 and R 26 may be bonded to each other to form a single bond or a linking group.]; Preferably, D is a group represented by the following general formula (4c);

[0325] [Chemical formula 36]

[0326] General formula (4c)

[0327]

[0328] [In the general formula (4c), R 31 ~R 40 each independently represents a hydrogen atom or a substituent. L represents a single bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group, R 31 and R 32 、R 32 and R 33 、R 33 and R 34 、R 34 and R 35 、R 36 and R 37 、R 37 and R 38 、R 38 and R 39 、R 39 and R 40 may be bonded to each other to form a linking group required for forming a cyclic structure. And, R 35 and R 36 may be bonded to each other to form a single bond or a linking group. * represents the bonding position to the carbon atom (C) of the ring skeleton constituting the benzene ring in the general formula (1).]; Preferably, L is a single bond; Preferably, R 3 is a cyano group and L is a substituted or unsubstituted phenylene group; Preferably, D is a group represented by any one of the following general formulas (5c) to (8c).

[0329] [Chemical formula 37]

[0330] General formula (5c)

[0331]

[0332] General formula (6c)

[0333]

[0334] General formula (7c)

[0335]

[0336] General formula (8c)

[0337]

[0338] [In general formulas (5c) to (8c), R 41 ~R 46 、R 51 ~R 60 、R 61 ~R 68 、R 71 ~R 78 each independently represents a hydrogen atom or a substituent. L 11 ~L 14 represents a single bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group. X in general formula (8c) represents a divalent oxygen atom, sulfur atom, substituted or unsubstituted nitrogen atom, substituted or unsubstituted carbon atom, substituted or unsubstituted silicon atom, carbonyl group, or a divalent substituted or unsubstituted vinyl group, substituted or unsubstituted vinylene group, substituted or unsubstituted orthoarylene group, or substituted or unsubstituted orthoheteroarylene group having a bond chain length of 2 atoms.]

[0339] Regarding the detailed description, preferred range, and specific compound examples of general formula (21), reference can be made to the relevant descriptions in PCT / JP2018 / 024302 and its published gazette, which are incorporated herein by reference as part of this specification.

[0340] As another specific compound group that can be used as the delayed phosphor of the second organic compound, for example, a compound group represented by the following general formula can be cited.

[0341] [Chemical formula 38]

[0342] General formula (22)

[0343]

[0344] In general formula (22), R 1 ~R5 Each independently represents a hydrogen atom or a substituent, R 1 ~R 5 Among them, 0 to 3 represent an aryl group Ar which may be substituted by an alkyl group or an aryl group (wherein, in the benzene ring constituting the latter aryl group, a ring containing an oxygen atom or a sulfur atom as a ring skeleton constituting atom in addition to a carbon atom may be condensed, but a ring containing a hetero atom other than an oxygen atom and a sulfur atom as a ring skeleton constituting atom will not be condensed). When two or more of R 1 ~R 5 are Ar, these Ar may be the same or different from each other. R 1 ~R 5 Among them, 1 to 4 represent a receptor group A (excluding the group corresponding to Ar). When two or more of R 1 ~R 5 are A, these A may be the same or different from each other. R 1 ~R 5 Among them, 1 to 4 represent a donor group D (excluding the group corresponding to Ar). When two or more of R 1 ~R 5 are D, these D may be the same or different from each other.

[0345] Preferably, 1 to 3 of R 1 ~R 5 are an aryl group Ar which may be substituted by an alkyl group or an aryl group; preferably, R 3 is a receptor group A; preferably, R 1 and R 5 are donor groups D; preferably, the donor group D is a substituted or unsubstituted diarylamino group (the two aryl groups constituting the diarylamino group may be bonded to each other); preferably, the donor group D is a substituted or unsubstituted diarylamino group and the two aryl groups constituting the diarylamino group are bonded to each other; preferably, the receptor group A is a substituted or unsubstituted heteroaryl group; preferably, the receptor group A is a heteroaryl group containing a nitrogen atom as a ring skeleton constituting atom; preferably, the receptor group A is an aryl-substituted heteroaryl group.

[0346] Regarding the detailed description, preferred range and specific compound examples of the general formula (22), reference can be made to the relevant descriptions of Japanese Patent Application 2017-168885 and its published gazette which are incorporated herein by reference as part of this specification.

[0347] Hereinafter, specific examples of the compounds that can be used as the second organic compound are exemplified. In the specific examples, Compounds 1 to 7 are determined in the table, and the structural formulas are also listed below. And Compounds 8 and later are only determined in the table. Among them, the compounds represented by the general formula (1) that can be used in the present invention should not be construed as being limited by these specific examples.

[0348] [Chemical formula 39]

[0349]

[0350] In the following table, specific examples of the compounds represented by the general formula (10) or the general formula (11) are listed. The general formulas (2a) and (2b) representing the substituents in the general formula (10) or the general formula (11) are also described below.

[0351] [Chemical formula 40]

[0352]

[0353]

[0354]

[0355]

[0356]

[0357]

[0358]

[0359]

[0360]

[0361]

[0362]

[0363]

[0364]

[0365]

[0366]

[0367]

[0368] [Table 8]

[0369]

[0370] In the following, specific compounds that are not included in the general formula (1) and can be used as the second compound of the present invention are also exemplified.

[0371] [Chemical formula 41-1]

[0372]

[0373] [Chemical Formula 41-2]

[0374]

[0375] [Chemical Formula 41-3]

[0376]

[0377] [Chemical Formula 41-4]

[0378]

[0379] [Chemical Formula 41-5]

[0380]

[0381] [Chemical Formula 41-6]

[0382]

[0383] The structures of D1 to D60 and A1 to A13 in the above Tables 1 to 8 are shown below.

[0384] [Chemical Formula 42]

[0385]

[0386] [Chemical Formula 43]

[0387]

[0388] [Chemical Formula 44]

[0389]

[0390] [Chemical Formula 45]

[0391]

[0392] [Chemical Formula 46]

[0393]

[0394] [The Third Organic Compound]

[0395] The third organic compound is a luminescent substance whose lowest excited singlet state energy is lower than that of the first organic compound and the second organic compound. The third organic compound receives energy from the first organic compound and the second organic compound in the excited singlet state and from the second organic compound that undergoes reverse intersystem crossing from the excited triplet state to become the excited singlet state, transitions to the singlet excited state, and emits fluorescence when returning to the ground state thereafter. As the luminescent substance used as the third organic compound, as long as it can receive energy from the first organic compound and the second organic compound and emit light in this way, there is no particular limitation, and the light emission can be fluorescence, delayed fluorescence, or phosphorescence. Among them, the luminescent substance used as the third organic compound is preferably a luminescent substance that emits fluorescence when returning from the lowest excited singlet state energy level to the ground state energy level. Two or more kinds of the third organic compound can be used as long as the relationship of formula (A) is satisfied. For example, it is possible to emit light of a desired color by simultaneously using two or more kinds of the third organic compound having different emission colors.

[0396] As the third organic compound, anthracene derivatives, tetracene derivatives, naphthacene derivatives, pyrene derivatives, perylene derivatives, derivatives, rubrene derivatives, coumarin derivatives, pyran derivatives, stilbene derivatives, fluorene derivatives, anthryl derivatives, terphenyl derivatives, terphenylene derivatives, fluoranthene derivatives, amine derivatives, quinacridone derivatives, oxadiazole derivatives, malononitrile derivatives, pyran derivatives, carbazole derivatives, julolidine derivatives, thiazole derivatives, derivatives having metals (Al, Zn), etc. can be used. These exemplified skeletons may or may not have substituents. And these exemplified skeletons can be combined with each other.

[0397] As a preferred compound that can be used as the third organic compound, the following compounds can be cited.

[0398] Anthracene

[0399] Tetracene

[0400] 5,6,11,12 - Tetraphenyltetracene

[0401] 2,8 - Di - tert - butyl - 5,11 - bis(4 - (tert - butyl)phenyl)-6,12 - diphenyltetracene

[0402] Perylene

[0403] 2,5,8,11 - Tetra - tert - butylperylene

[0404] 1,3,6,8 - Tetraphenylpyrene

[0405] Benzo[e]pyrene

[0406] 5,12-Dihydroquinolino[2,3-b]acridine-7,14-dione

[0407] 5,12-Dimethyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione

[0408] 5,12-Di-tert-butyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione

[0409] 5,12-Di-tert-butyl-1,3,8,10-tetramethyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione

[0410] 3-(Benzo[d]thiazol-2-yl)-7-(diethylamino)-2H-chromen-2-one

[0411] 3-(1H-Benzimidazol-2-yl)-7-(diethylamino)-2H-chromen-2-one

[0412] 7-(Diethylamino)-3-(1-methyl-1H-benzimidazol-2-yl)-2H-chromen-2-one

[0413] 10-(Benzo[d]thiazol-2-yl)-2,3,6,7-tetrahydro-1H,5H,11H-pyrano[2,3-f]pyrido[3,2,1-ij]quinolin-11-one

[0414] 10-(Benzo[d]thiazol-2-yl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-pyrano[2,3-f]pyrido[3,2,1-ij]quinolin-11-one

[0415] 7-(Dimethylamino)-4-(trifluoromethyl)-2H-chromen-2-one

[0416] 7-(Diethylamino)-4-(trifluoromethyl)-2H-chromen-2-one

[0417] 1,1,7,7-Tetramethyl-9-(trifluoromethyl)-2,3,6,7-tetrahydro-1H,5H,11H-pyrano[2,3-f]pyrido[3,2,1-ij]quinolin-11-one

[0418] (E)-2-(2-(4-(Dimethylamino)styryl)-6-methyl-4H-pyran-4-ylidene)malononitrile

[0419] (E)-2-(2-Methyl-6-(2-(2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)vinyl)-4H-pyran-4-ylidene)malononitrile

[0420] (E)-2-(2-Methyl-6-(2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)vinyl)-4H-pyran-4-ylidene)malononitrile

[0421] (E)-2-(2-(tert-Butyl)-6-(2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)vinyl)-4H-pyran-4-ylidene)malononitrile

[0422] (E)-2-(2-(tert-Butyl)-6-(2-(2,6,6-trimethyl-1,2,5,6-tetrahydro-4H-pyrrolo[3,2,1-ij]quinolin-8-yl)vinyl)-4H-pyran-4-ylidene)malononitrile

[0423] (E)-2-(2-(4-(Dimethylamino)styryl)-1-ethylquinolin-4(1H)-ylidene)malononitrile

[0424] (E)-2-(2-(2-(7-(4-(Bis(4-methoxyphenyl)amino)phenyl)-2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)vinyl)-1-ethylquinolin-4(1H)-ylidene)malononitrile

[0425] 4,4’-((1E,1’E)-1,4-Phenylenebis(ethene-2,1-diyl))bis(N,N-diphenylaniline)

[0426] 4,4’-((1E,1’E)-1,4-Phenylenebis(ethene-2,1-diyl))bis(N,N-di-p-tolylaniline)

[0427] 1,4-Bis((E)-4-(9H-carbazol-9-yl)styryl)benzene

[0428] 4,4’-((1E,1’E)-[1,1’-Biphenyl]-4,4’-diylbis(ethene-2,1-diyl))bis(N,N-diphenylaniline)

[0429] 4,4’-((1E,1’E)-[1,1’-Biphenyl]-4,4’-diylbis(ethene-2,1-diyl))bis(N,N-di-p-tolylaniline)

[0430] 4,4’-((1E,1’E)-9,9’-Spirobi[fluorene]-2,7-diylbis(ethene-2,1-diyl))bis(N,N-diphenylaniline)

[0431] 4,4’-Bis((E)-4-(9H-carbazol-9-yl)styryl)-1,1’-biphenyl

[0432] 4,4’-((1E,1’E)-Naphthalene-2,6-diylbis(ethene-2,1-diyl))bis(N,N-diphenylaniline)

[0433] 4,4’-((1E,1’E)-Naphthalene-2,6-diylbis(ethene-2,1-diyl))bis(N,N-bis(4-hexylphenyl)aniline)

[0434] 1,4-Bis((E)-2-(9-ethyl-9H-carbazol-3-yl)vinyl)benzene

[0435] 4,4’-Bis((E)-2-(9-ethyl-9H-carbazol-3-yl)vinyl)-1,1’-biphenyl

[0436] 1,1,4,4-Tetraphenyl-1,3-butadiene

[0437] (E)-N,N-Diphenyl-4-styrylaniline

[0438] (E)-N,N-Diphenyl-4-(4-(pyren-1-yl)styryl)aniline

[0439] (E)-9,9-Diethyl-N,N-diphenyl-7-(4-(9-phenyl-9H-fluoren-9-yl)styryl)-9H-fluorene-2-amine

[0440] Tris(quinolin-8-olato)aluminum

[0441] Bis(2-(benzo[d]oxazol-2-yl)phenoxy)zinc

[0442] Bis(2-(benzo[d]thiazol-2-yl)phenoxy)zinc

[0443] Bis(quinolin-8-olato)zinc

[0444] N4,N4,N4”’,N4”’-Tetraphenyl-[1,1’:4’,1”:4”,1”’-quaterphenyl]-4,4”’-diamine

[0445] 9,9,9’,9’,9”,9”-Hexamethyl-N7,N7”-diphenyl-N7,N7”-di-m-tolyl-9H,9’H,9”H-[2,2’:7’,2”-terfluorene]-7,7”-diamine

[0446] 9,9,9’,9’,9”,9”-Hexamethyl-N7,N7”-bis(naphthalen-2-yl)-N7,N7”-diphenyl-9H,9’H,9”H-[2,2’:7’,2”-terfluorene]-7,7”-diamine

[0447] N9,N10-Diphenyl-N9,N10-di-p-tolylanthracene-9,10-diamine

[0448] N9,N10-Diphenyl-N9,N10-di-m-tolylanthracene-9,10-diamine

[0449] N9,N10-Bis(naphthalen-2-yl)-N9,N10-diphenylanthracene-9,10-diamine

[0450] N9,N9,N10,N10-Tetra-p-tolylanthracene-9,10-diamine

[0451] N10,N10,N10’,N10’-Tetraphenyl-[9,9’-bianthracene]-10,10’-diamine

[0452] N10,N10,N10’,N10’-Tetra-p-tolyl-[9,9’-bianthracene]-10,10’-diamine

[0453] N10,N10’-Bis(4-isopropylphenyl)-N10,N10’-di-p-tolyl-[9,9’-bianthracene]-10,10’-diamine

[0454] N10,N10’-Bis(naphthalen-1-yl)-N10,N10’-diphenyl-[9,9’-bianthracene]-10,10’-diamine

[0455] N,N-Diphenyldibenzo[g,p]chrysene-2-amine

[0456] N5,N5,N9,N9-Tetraphenylspiro[benzo[c]fluorene-7,9’-fluorene]-5,9-diamine

[0457] N5,N9-Diphenyl-N5,N9-di-m-tolylspiro[benzo[c]fluorene-7,9’-fluorene]-5,9-diamine

[0458] 2,6-Bis(diphenylamino)anthracene-9,10-dione

[0459] 9,9’-Diphenyl-9H,9’H-3,3’-bicarbazole

[0460] 3-(10-(Naphthalen-1-yl)anthracen-9-yl)-9-phenyl-9H-carbazole

[0461] Cyclopenta-1,3-diene-1,2,3,4-tetrayltetraphene

[0462] Cyclopenta-1,3-diene-1,2,3,4,5-pentylpentaphene

[0463] 15,15-Difluoro-3,11-dimethyl-15H-14l4,15l4-[1,3,5,2]triazaborolo[1,6-a:3,4-a']biquinoline

[0464] 10,10'-Bis(3,5-bis(trifluoromethyl)phenyl)-9,9'-bianthracene

[0465] 9,10-Bis(4-(benzothiazol-2-yl)phenyl)anthracene

[0466] [Chemical Formula 47-1]

[0467]

[0468] [Chemical Formula 47-2]

[0469]

[0470] Moreover, the luminescent material described in the following publication can be used as the third organic compound of the present invention.

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[0472] Here, JP represents a Japanese gazette, WO represents an international gazette, and H represents Heisei. The gazettes described in this paragraph are all cited here as part of this specification.

[0473] Regarding the molecular weights of the second organic compound and the third organic compound, for example, when attempting to form and utilize an organic layer containing the compound by vapor deposition, it is preferably 1500 or less, more preferably 1200 or less, further preferably 1000 or less, and even more preferably 800 or less. The second organic compound and the third organic compound can be formed into a film by a coating method regardless of their molecular weights. If the coating method is used, a film can be formed even for a compound with a relatively large molecular weight.

[0474] It is also possible to consider applying the present invention and using a compound containing a plurality of the structures represented by the above general formula in the molecule as the second organic compound or the third organic compound.

[0475] For example, taking the general formula (1) as an example, it is possible to consider using a polymer obtained by pre-existing a polymerizable group in the structure represented by the general formula (1) and polymerizing the polymerizable group as the second compound. Specifically, it is possible to consider preparing a monomer containing a polymerizable functional group in any of L, A, and D of the general formula (1), polymerizing it alone or copolymerizing it with other monomers, thereby obtaining a polymer having a repeating unit, and using this polymer as a light-emitting material. Alternatively, it is also possible to consider obtaining a dimer or trimer by coupling compounds having the structure represented by the general formula (1) and using these as light-emitting materials.

[0476] As an example of a polymer having a repeating unit containing the structure represented by the above general formula and used as the second organic compound or the third organic compound, a polymer containing the structure represented by the following general formula (23) or general formula (24) can be cited.

[0477] [Chemical formula 48]

[0478]

[0479] In the general formula (23) or general formula (24), Q represents a group containing the structure represented by the above general formula, L 1 and L 2represents a linking group. The number of carbon atoms in the linking group is preferably 0 to 20, more preferably 1 to 15, and still more preferably 2 to 10. The linking group is preferably a linking group having a structure represented by -X 11 -L 11 -. Here, X 11 represents an oxygen atom or a sulfur atom, preferably an oxygen atom. L 11 represents a linking group, preferably a substituted or unsubstituted alkylene group or a substituted or unsubstituted arylene group, more preferably a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms or a substituted or unsubstituted phenylene group.

[0480] In general formula (23) or general formula (24), R 201 , R 202 , R 203 and R 204 each independently represent a substituent. Preferably, they are a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a halogen atom. More preferably, they are an unsubstituted alkyl group having 1 to 3 carbon atoms, an unsubstituted alkoxy group having 1 to 3 carbon atoms, a fluorine atom, or a chlorine atom. Still more preferably, they are an unsubstituted alkyl group having 1 to 3 carbon atoms and an unsubstituted alkoxy group having 1 to 3 carbon atoms.

[0481] L 1 and L 2 The linking groups represented by, for example, can be bonded to any one of L, A, and D in the structure of general formula (1) constituting Q. Two or more linking groups can be connected to one Q to form a crosslinked structure or a network structure.

[0482] As specific structural examples of the repeating unit, the structures represented by the following general formulas (25) to (28) can be cited.

[0483] [Chemical formula 49]

[0484]

[0485] Polymers having repeating units including these general formulas (25) to (28) can be synthesized, for example, by introducing a hydroxyl group into any one of L, A, and D in the structure of general formula (1) in advance, using it as a linking group to react the following compound to introduce a polymerizable group, and polymerizing the polymerizable group.

[0486] [Chemical formula 50]

[0487]

[0488] The polymer containing the structure represented by the above general formula within the molecule may be a polymer composed only of repeating units having the structure represented by the above general formula, or may be a polymer containing repeating units having other structures. Further, the repeating units having the structure represented by the general formula contained in the polymer may be a single type or two or more types. As the repeating units not having the structure represented by the general formula, repeating units derived from monomers usually used for copolymerization can be cited. For example, repeating units derived from monomers having an ethylenically unsaturated bond such as ethylene and styrene can be cited.

[0489] [Content and combination of compounds]

[0490] The content of each organic compound contained in the light-emitting layer is not particularly limited, but the content of the second organic compound is preferably less than the content of the first organic compound. Thereby, higher luminous efficiency can be obtained. Specifically, when the total weight of the content W1 of the first organic compound, the content W2 of the second organic compound, and the content W3 of the third organic compound is set to 100% by weight, the content W1 of the first organic compound is preferably 15% by weight or more and 99.9% by weight or less, the content W2 of the second organic compound is preferably 5.0% by weight or more and 50% by weight or less, and the content W3 of the third organic compound is preferably 0.5% by weight or more and 5.0% by weight or less.

[0491] When manufacturing the organic electroluminescent element, the first organic compound, the second organic compound, and the third organic compound may be used only for one layer, or may be used for other layers. For example, one or more of the first organic compound, the second organic compound, and the third organic compound may be used for the above-mentioned injection layer, blocking layer, hole blocking layer, electron blocking layer, exciton blocking layer, hole transport layer, electron transport layer, and the like. The film formation method of these layers is not particularly limited, and either a dry process or a wet process can be used for manufacturing.

[0492] Specific combination examples of the second compound and the third compound used when manufacturing the organic electroluminescent element are shown in the following table. The vertical axis represents Compounds 1 to 678 exemplified as the second compound, and the horizontal axis represents Compounds D1 to D25 exemplified as the third compound. For each combination determined by the second compound on the horizontal axis and the third compound on the vertical axis, combination numbers 1 to 16950 are sequentially marked.

[0493] In the present invention, the first organic compound, the second organic compound, and the third organic compound preferably do not contain metal atoms, and more preferably are compounds composed only of atoms selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, a sulfur atom, a silicon atom, and a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom). For example, a compound composed only of atoms selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, and a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom) can be selected, or a compound composed only of atoms selected from the group consisting of a carbon atom, a hydrogen atom, and a nitrogen atom can be selected.

[0494]

[0495]

[0496]

[0497]

[0498]

[0499]

[0500]

[0501]

[0502]

[0503]

[0504]

[0505]

[0506]

[0507] [Other organic compounds]

[0508] The light-emitting layer may be composed only of the first organic compound to the third organic compound, or may contain organic compounds other than the first organic compound to the third organic compound. As the organic compounds other than the first organic compound to the third organic compound, for example, organic compounds having hole-transporting ability, organic compounds having electron-transporting ability, etc. can be cited. As the organic compounds having hole-transporting ability and the organic compounds having electron-transporting ability, the following hole-transporting materials and electron-transporting materials can be referred to respectively.

[0509] [Substrate]

[0510] The organic electroluminescent element of the present invention is preferably supported by a substrate. Regarding this substrate, there is no particular limitation as long as it is a substrate conventionally used in organic electroluminescent elements. For example, a substrate made of glass, transparent plastic, quartz, silicon, etc. can be used.

[0511] [Anode]

[0512] As the anode of the organic electroluminescent element, an anode using a metal, alloy, conductive compound, or a mixture thereof having a large work function (4 eV or more) as the electrode material can be preferably used. Specific examples of such electrode materials include metals such as Au, conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO. Also, an amorphous material such as IDIXO (In2O3-ZnO) that can form a transparent conductive film can be used. Regarding the anode, these electrode materials can be formed into a thin film by methods such as evaporation or sputtering, and a pattern of a required shape can be formed using photolithography. Or, in the case where the pattern accuracy requirement is not high (about 100 μm or more), a pattern can be formed via a mask of a required shape during the evaporation or sputtering of the above electrode materials. Or, in the case of using a material such as an organic conductive compound that can be coated, wet film formation methods such as printing and coating can also be used. When extracting light emission from this anode, it is preferable to set the transmittance to be greater than 10%, and the sheet resistance of the anode is preferably several hundred Ω / sq or less. Moreover, the film thickness also depends on the material and is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

[0513] [Cathode]

[0514] On the other hand, as the cathode, a cathode using a metal with a small work function (4 eV or less) (referred to as an electron-injecting metal), an alloy, a conductive compound, or a mixture thereof as an electrode material can be used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al2O3) mixture, indium, lithium / aluminum mixture, rare earth metals, etc. Among them, from the viewpoints of electron injection and durability against oxidation, etc., a mixture of an electron-injecting metal and a second metal, which is a metal having a larger and stable work function value than that of the electron-injecting metal, is preferred. For example, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al2O3) mixture, lithium / aluminum mixture, aluminum, etc. Regarding the cathode, these electrode materials can be formed into a thin film by using methods such as evaporation or sputtering to fabricate it. And, the film resistance of the cathode is preferably several hundred Ω / square or less, and the film thickness is generally selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In addition, if either the anode or the cathode of the organic electroluminescent element is transparent or translucent in order to transmit the emitted light, the luminous brightness is increased and it is preferred.

[0515] Moreover, by using the conductive transparent material cited in the description of the anode for the cathode, a transparent or translucent cathode can be fabricated. By applying this cathode, two transmissive elements, namely the anode and the cathode, can be fabricated.

[0516] [Injection layer]

[0517] The injection layer refers to a layer provided between the electrode and the organic layer in order to reduce the driving voltage or increase the luminous brightness. There are a hole injection layer and an electron injection layer, and it can be present between the anode and the light-emitting layer or the hole transport layer and between the cathode and the light-emitting layer or the electron transport layer. The injection layer can be provided as needed.

[0518] [Blocking layer]

[0519] The blocking layer is a layer capable of preventing the charge (electron or hole) and / or exciton present in the light-emitting layer from diffusing outside the light-emitting layer. The electron blocking layer can be disposed between the light-emitting layer and the hole transport layer to prevent electrons from passing through the light-emitting layer toward the hole transport layer. Similarly, the hole blocking layer can be disposed between the light-emitting layer and the electron transport layer to prevent holes from passing through the light-emitting layer toward the electron transport layer. The blocking layer can also be used to prevent excitons from diffusing outside the light-emitting layer. That is, the electron blocking layer and the hole blocking layer can each also serve as an exciton blocking layer. The electron blocking layer or exciton blocking layer described in this specification is used in the sense of including a layer having the functions of an electron blocking layer and an exciton blocking layer as one layer.

[0520] [Hole blocking layer]

[0521] The hole blocking layer generally has the function of an electron transport layer. The hole blocking layer has the function of transporting electrons and preventing holes from reaching the electron transport layer, thereby increasing the recombination probability of electrons and holes in the light-emitting layer. As the material for the hole blocking layer, the materials for the electron transport layer described later can be used as needed.

[0522] [Electron blocking layer]

[0523] The electron blocking layer generally has the function of transporting holes. The electron blocking layer has the function of transporting holes and preventing electrons from reaching the hole transport layer, thereby increasing the recombination probability of electrons and holes in the light-emitting layer.

[0524] [Exciton blocking layer]

[0525] The exciton blocking layer refers to a layer used to block the diffusion of excitons generated by the recombination of holes and electrons in the light-emitting layer to the charge transport layer. By inserting this layer, excitons can be efficiently confined in the light-emitting layer, and the luminous efficiency of the device can be improved. The exciton blocking layer is adjacent to the light-emitting layer and can be inserted on either the anode side or the cathode side, or can be inserted on both sides simultaneously. That is, when there is an exciton blocking layer on the anode side, it can be inserted adjacent to the light-emitting layer between the hole transport layer and the light-emitting layer. When inserted on the cathode side, it can be inserted adjacent to the light-emitting layer between the light-emitting layer and the cathode. Moreover, between the anode and the exciton blocking layer on the anode side adjacent to the light-emitting layer, there can be a hole injection layer or an electron blocking layer, etc. Between the cathode and the exciton blocking layer on the cathode side adjacent to the light-emitting layer, there can be an electron injection layer, an electron transport layer, a hole blocking layer, etc. When configuring the blocking layer, it is preferably that at least one of the singlet excitation energy and the triplet excitation energy of the material used as the blocking layer is higher than the singlet excitation energy and the triplet excitation energy of the luminescent material.

[0526] [Hole transport layer]

[0527] The hole transport layer is composed of a hole transport material having the function of transporting holes, and the hole transport layer can be provided as a single layer or multiple layers.

[0528] As a hole transport material, it has any one of hole injection or transport and electron blocking properties, and can be either an organic or an inorganic substance. As well-known hole transport materials that can be used, for example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolinone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline-based copolymers can be cited. Conductive polymer oligomers can also be cited, and in particular, thiophene oligomers and the like can be cited. Porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds are preferably used, and aromatic tertiary amine compounds are more preferably used.

[0529] [Electron transport layer]

[0530] The electron transport layer is composed of a material having the function of transporting electrons, and the electron transport layer can be provided as a single layer or multiple layers.

[0531] As an electron transport material (there are cases where it also serves as a hole blocking material), it only needs to have the function of transferring electrons injected from the cathode to the light-emitting layer. As electron transport layers that can be used, for example, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimide, fluorenedimethylene derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, etc. can be cited. Moreover, among the above oxadiazole derivatives, thiadiazole derivatives obtained by substituting the oxygen atom of the oxadiazole ring with a sulfur atom and quinoxaline derivatives having a quinoxaline ring known as an electron-withdrawing group can also be used as electron transport materials. In addition, polymer materials in which these materials are introduced into the polymer chain or these materials are used as the main chain of the polymer can also be used.

[0532] [Examples of materials that can be used in organic electroluminescent elements]

[0533] Hereinafter, preferred materials that can be used in organic electroluminescent elements are specifically exemplified. Among them, the materials that can be used in the present invention are not limitedly interpreted by the following exemplified compounds. And even compounds exemplified as materials having specific functions can also be used as materials having other functions. In addition, R, R2 to R7 in the structural formulas of the following exemplified compounds each independently represent a hydrogen atom or a substituent. n represents an integer of 3 to 5.

[0534] First, preferred compound examples that can be used as hole injection materials are cited.

[0535] [Chemical formula 51]

[0536]

[0537] Next, preferred compound examples that can be used as hole transport materials are given.

[0538] [Chemical formula 52]

[0539]

[0540] [Chemical formula 53]

[0541]

[0542] [Chemical formula 54]

[0543]

[0544] [Chemical formula 55]

[0545]

[0546] [Chemical formula 56]

[0547]

[0548] [Chemical formula 57]

[0549]

[0550] Next, preferred compound examples that can be used as electron blocking materials are given.

[0551] [Chemical formula 58]

[0552]

[0553] Next, preferred compound examples that can be used as hole blocking materials are given.

[0554] [Chemical formula 59]

[0555]

[0556] Next, preferred compound examples that can be used as electron transport materials are given.

[0557] [Chemical formula 60]

[0558]

[0559] [Chemical formula 61]

[0560]

[0561] [Chemical formula 62]

[0562]

[0563] Next, preferred compound examples that can be used as an electron injection material are given.

[0564] [Chemical formula 63]

[0565]

[0566] Moreover, preferred compound examples of materials that can be added are given. For example, addition as a stabilizing material can be considered, etc.

[0567] [Chemical formula 64]

[0568]

[0569] [Luminescence]

[0570] The organic electroluminescent element produced by the above method emits light by applying an electric field between the anode and the cathode of the obtained element. At this time, as long as the light emission is based on the singlet excited state energy, light with a wavelength corresponding to its energy level is recognized as fluorescence emission and delayed fluorescence emission. And, as long as the light emission is based on the triplet excited state energy, the wavelength corresponding to its energy level is recognized as phosphorescence. The fluorescence lifetime of ordinary fluorescence is shorter than that of delayed fluorescence emission, so the emission lifetime can be distinguished according to fluorescence and delayed fluorescence.

[0571] On the other hand, regarding phosphorescence, in ordinary organic compounds such as the compounds of the present invention, the triplet excited state energy is unstable and converted into heat, etc., and the lifetime is short and it is immediately inactivated, so it can hardly be observed at room temperature. In order to measure the triplet excited state energy of ordinary organic compounds, it can be measured by observing the light emission under extremely low temperature conditions.

[0572] [Application]

[0573] The organic electroluminescent element of the present invention can be applied in any of a single element, an element composed of an array-like configuration structure, and a structure in which an anode and a cathode are arranged in an X-Y matrix. According to the present invention, by making the light-emitting layer contain a first organic compound, a second organic compound, and a third organic compound that satisfy the conditions of the present invention, an organic light-emitting element with a greatly improved luminous efficiency can be obtained. Organic light-emitting elements such as the organic electroluminescent element of the present invention can be further applied to various uses. For example, an organic electroluminescent display device can be manufactured using the organic electroluminescent element of the present invention. Specifically, reference can be made to "Organic EL Displays" (Ohmsha, Ltd.) co-authored by Shizuo Tokumitsu, Chihaya Adachi, and Hideyuki Murata. And, in particular, the organic electroluminescent element of the present invention can also be applied to organic electroluminescent lighting or backlights with high demand.

[0574] Examples

[0575] Examples are given below to further specifically illustrate the features of the present invention. The materials, treatment contents, treatment steps, etc. shown below can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below. In addition, for the evaluation of luminescence characteristics, a high-performance ultraviolet-visible-near-infrared spectrophotometer (manufactured by PerkinElmeR Co., Ltd.: Lambda950), a fluorescence spectrophotometer (manufactured by HORIBA, Ltd.: FluoroMax-4), an absolute PL quantum yield measurement device (manufactured by Hamamatsu Photonics K.K.: C11347), a source meter (manufactured by Keithley Corporation: 2400 series), a semiconductor parameter analyzer (manufactured by Agilent Technologies Japan, Ltd.: E5273A), an optical power meter measurement device (manufactured by Newport Corporation: 1930C), a spectrometer (manufactured by OceanOptics Corporation: USB2000), a spectroradiometer (manufactured by TOPCON CORPORATION: SR-3), and a streak camera (manufactured by Hamamatsu Photonics K.K.: type C4334) were used.

[0576] Synthesis of Compounds

[0577] (Synthesis Example 1) Synthesis of Compound 1

[0578] [Chemical Formula 65]

[0579]

[0580] Compound z was synthesized by the same method as described in Adv. Opt. Mater. 4, 688 - 693 (2016).

[0581] Next, under a nitrogen stream, 3,6-dimethylcarbazole (0.39 g, 1.98 mmol) was added to a tetrahydrofuran solution (20 mL) of sodium hydride (60% mineral oil dispersion, 0.08 g, 1.98 mmol), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to 0 °C and compound z (0.5 g, 0.79 mmol) was added, and the mixture was stirred at 50 °C for 12 hours. The reaction mixture was added to ice water for quenching and filtration to obtain a crude product. The obtained crude product was purified by silica gel column chromatography (toluene:hexane = 3:2) to obtain yellow solid compound 1 (0.79 g, 0.75 mmol, yield 95%).

[0582] 1 1H NMR: (500 MHz, acetone-d6): δ (ppm) = 7.83 (d, J = 8.2 Hz, 4H), 7.71 (d, J = 7.1 Hz, 4H), 7.64 (d, J = 8.3 Hz, 2H), 7.45 (d, J = 8.4 Hz, 2H), 7.34 (d, J = 7.2 Hz, 2H), 7.09 (m, 12H), 6.72 (t, J = 7.9 Hz, 2H), 6.62 (d, J = 8.4 Hz, 2H), 6.45 (d, J = 8.3 Hz, 4H), 2.11 (s, 12H)

[0583] (Synthesis Example 2) Synthesis of Compound 2

[0584] [Chemical Formula 66]

[0585]

[0586] Under a nitrogen stream, to a solution of sodium hydride (60% mineral oil dispersion, 0.14 g, 3.58 mmol) in tetrahydrofuran (20 mL) was added 3,6-di-tert-butylcarbazole (1 g, 3.58 mmol), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to 0 °C and compound z (1.04 g, 1.63 mmol) was added, and the mixture was stirred at 50 °C for 12 hours. The reaction mixture was quenched by adding it to ice water and filtered to obtain a crude product. The obtained crude product was purified by silica gel column chromatography (toluene:hexane = 1:1) to obtain compound 2 as a yellow solid (1.8 g, 1.56 mmol, yield 96%).

[0587] (Synthesis Example 3) Synthesis of Compound 3

[0588] [Chemical Formula 67]

[0589]

[0590] Under a nitrogen stream, to a solution of sodium hydride (60% mineral oil dispersion, 0.13 g, 3.15 mmol) in tetrahydrofuran (20 mL) was added 3,6-diphenylcarbazole (1 g, 3.15 mmol), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to 0 °C and compound z (0.8 g, 1.26 mmol) was added, and the mixture was stirred at 50 °C for 12 hours. The reaction mixture was quenched by adding it to ice water and filtered to obtain a crude product. The obtained crude product was purified by silica gel column chromatography (toluene:hexane = 3:2) to obtain compound 3 as a yellow solid (1.36 g, 1.10 mmol, yield 87%).

[0591] 11H NMR: (500 MHz, acetone-d6): δ (ppm) = 7.82 (m, 14H), 7.72 (d, J = 8.7 Hz, 4H), 7.45 (m, 8H), 7.35 (m, 10H), 7.26 (t, J = 8.6 Hz, 4H), 7.16 (t, J = 8.3 Hz, 4H), 7.10 (t, J = 7.9 Hz, 4H), 6.98 (d, J = 8.6 Hz, 4H), 6.75 (m, 4H)

[0592] (Synthesis Example 4) Synthesis of Compound 4

[0593] [Chemical Formula 68]

[0594]

[0595] Compound y was synthesized by the same method as described in Adv. Opt. Mater. 4, 688 - 693 (2016).

[0596] Next, under a nitrogen stream, 3,6 - dimethylcarbazole (0.37 g, 1.92 mmol) was added to a solution of sodium hydride (60% mineral oil dispersion, 0.08 g, 1.92 mmol) in tetrahydrofuran (20 mL), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to 0 °C and compound y (1.0 g, 1.28 mmol) was added, and the mixture was stirred at 50 °C for 12 hours. The reaction mixture was quenched by adding it to ice water and filtered to obtain a crude product. The obtained crude product was purified by silica gel column chromatography (toluene:hexane = 3:2) to obtain compound 4 as a yellow solid (1.08 g, 1.13 mmol, yield 88%).

[0597] (Synthesis Example 5) Synthesis of Compound 5

[0598] [Chemical Formula 69]

[0599]

[0600] Under a nitrogen stream, 3,6 - di - tert - butylcarbazole (0.54 g, 1.92 mmol) was added to a solution of sodium hydride (60% mineral oil dispersion, 0.08 g, 1.92 mmol) in tetrahydrofuran (20 mL), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to 0 °C and compound y (1.0 g, 1.28 mmol) was added, and the mixture was stirred at 50 °C for 12 hours. The reaction mixture was quenched by adding it to ice water and filtered to obtain a crude product. The obtained crude product was purified by silica gel column chromatography (toluene:hexane = 3:2) to obtain compound 5 as a yellow solid (1.16 g, 1.11 mmol, yield 87%).

[0601] (Synthesis Example 6) Synthesis of Compound 6

[0602] [Chemical Formula 70]

[0603]

[0604] Under a nitrogen stream, 3,6-diphenylcarbazole (0.61 g, 1.92 mmol) was added to a solution of sodium hydride (60% mineral oil dispersion, 0.08 g, 1.92 mmol) in tetrahydrofuran (20 mL), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to 0 °C and Compound y (1.0 g, 1.28 mmol) was added, and the mixture was stirred at 50 °C for 12 hours. The reaction mixture was quenched by adding it to ice water and filtered to obtain a crude product. The obtained crude product was purified by silica gel column chromatography (toluene:hexane = 3:2) to obtain Compound 6 as a yellow solid (1.18 g, 1.09 mmol, yield 85%).

[0605] 1 H NMR: (500 MHz, acetone-d6): δ (ppm) = 7.82 (m, 8H), 7.75 (m, 4H), 7.67 (t, J = 7.8 Hz, 4H), 7.45 (m, 4H), 7.35 (m, 8H), 7.25 (t, J = 8.0 Hz, 2H), 7.11 (m, 8H), 6.95 (d, J = 8.6 Hz, 2H), 6.74 (m, 4H), 6.66 (t, J = 7.8 Hz, 4H)

[0606] (Synthesis Example 7) Synthesis of Compound 7

[0607] [Chemical Formula 71]

[0608]

[0609] Under a nitrogen stream, 3,9'-bicarbazole (0.66 g, 1.98 mmol) was added to a solution of sodium hydride (60% mineral oil dispersion, 0.08 g, 1.98 mmol) in tetrahydrofuran (15 mL), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to 0 °C and Compound z (0.5 g, 0.79 mmol) was added, and the mixture was stirred at 50 °C for 12 hours. The reaction mixture was quenched by adding it to ice water and filtered to obtain a crude product. The obtained crude product was purified by silica gel column chromatography (toluene:hexane = 1:1) to obtain Compound 7 as a yellow solid (0.54 g, 0.43 mmol, yield 54%).

[0610] (Synthesis Example 8) Synthesis of Compound 11

[0611] [Chemical Formula 72]

[0612]

[0613] Under a nitrogen stream, 3-methyl-9H-carbazole (0.51 g, 2.83 mmol) was added to a tetrahydrofuran solution (15 mL) of sodium hydride (60% mineral oil dispersion, 0.15 g, 3.78 mmol), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to 50 °C and compound z (0.6 g, 0.95 mmol) was added. It was heated to 50 °C and stirred for 12 hours to obtain a reaction mixture. Water was added to the reaction mixture to cause precipitation, and the precipitate was then filtered. The filtered mixture was purified by silica gel column chromatography (toluene) to obtain compound B (0.65 g, 0.68 mmol, yield 71.9%).

[0614] 1 H-NMR (500 MHz, CDCl3, δ): 7.76 - 7.72 (m, 4H), 7.30 - 7.12 (m, 10H), 7.10 - 7.02 (m, 10H), 6.98 (t, J = 8.5 Hz, 2H), 6.91 (t, J = 8.5 Hz, 2H), 6.76 - 6.71 (m, 4H), 6.61 - 6.53 (m, 4H), 6.41 (t, J = 8.5 Hz, 2H), 2.17 - 2.16 (m, 6H)

[0615] ASAP mass spectrometry: Theoretical value 956.4, Observed value 957.3

[0616] (Synthesis Example 9) Synthesis of Compound 35

[0617] [Chemical Formula 73]

[0618]

[0619] Under a nitrogen stream, to a toluene solution (50 mL) of tributyltin chloride (5.06 g, 4.45 mL, 13.78 mmol) and 4-bromo-2,3,5,6-tetrafluorobenzonitrile (2.92 g, 11.50 mmol) were added tris(o-tolyl)phosphine (0.525 g, 1.72 mmol) and tris(dibenzylideneacetone)palladium(0) (1.57 g, 1.72 mmol). The temperature was raised to 100 °C and stirred for 21 hours. The mixture was returned to room temperature and quenched by adding water, extracted with ethyl acetate, and filtered through diatomaceous earth. Subsequently, the organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the obtained mixture was purified by silica gel column chromatography (dichloromethane:hexane = 1:2) to obtain a white solid compound a (2.42 g, 9.63 mmol, yield 83.7%).

[0620] 1 H-NMR (500 MHz, CDCL3, δ): 7.56 - 7.51 (m, 3H), 7.48 - 7.45 (m, 2H)

[0621] ASAP mass spectrometry: Theoretical value 251.0, Observed value 251.1

[0622] Under a nitrogen stream, to a tetrahydrofuran solution (10 mL) of sodium hydride (60% mineral oil dispersion, 0.125 g, 3.14 mmol) was added 9H-carbazole (0.397 g, 2.38 mmol), and stirred at room temperature for 1 hour. The mixture was cooled to -50 °C and compound a (0.3 g, 1.19 mmol) was added. The cooling bath was removed, and it was stirred while gradually returning to room temperature for 22 hours. The reaction mixture was quenched by adding it to ice water, extracted with ethyl acetate, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the obtained mixture was purified by silica gel column chromatography (chloroform:hexane = 1:2) to obtain a yellow solid compound b (0.486 g, 0.89 mmol, yield 74.8%).

[0623] 1 H-NMR (500 MHz, CDCL3, δ): 8.16 (d, J = 7.5 Hz, 4H), 7.62 - 7.59 (m, 2H), 7.54 - 7.49 (m, 7H), 7.38 (dt, J = 7.5 Hz, 1.0 Hz, 4H), 7.30 (d, J = 7.5 Hz, 4H)

[0624] ASAP mass spectrometry: Theoretical value 545.2, Observed value 545.2

[0625] [Chemical Formula 74]

[0626]

[0627] 0.575 g (2.36 mmol) of 3-phenyl-9H-carbazole, 0.702 g (3.94 mmol) of potassium carbonate, and 0.5 g (0.788 mmol) of Compound b were added to a 100 mL three-necked flask, and the flask was purged with nitrogen. After adding 10 mL of dehydrated 1-methyl-2-pyrrolidone to the mixture, the mixture was heated and stirred at 100 °C for 12 hours under a nitrogen atmosphere. After stirring, the mixture was returned to room temperature, water was added, and suction filtration was carried out. The obtained solid was dissolved in toluene and purified by silica gel column chromatography. The obtained fraction was concentrated and recrystallized from a mixed solvent of chloroform and acetonitrile, and as a result, Compound 35 as a pale yellow solid was obtained (yield: 0.60 g, yield: 77%).

[0628] 1 H NMR (500 MHz, CDCL3, δ): 7.77 (d, J = 1.2, 2H), 7.55 - 7.69 (m, 4H), 7.60 (d, J = 7.5 Hz, 2H), 7.51 (dd, J = 8.5 Hz, 4H), 7.42 (td, J = 8.0, J = 2.0, 4H), 7.32 - 6.94 (m, 24H), 6.75 (d, J = 7.5, 2H), 6.55 (td, J = 7.51, J = 1.2, 1H), 6.46 (t, J = 7.5, 2H)

[0629] ASAP mass spectrometry: theoretical value 991.37, observed value 992.39

[0630] (Synthesis Example 10) Synthesis of Compound 38

[0631] [Chemical Formula 75]

[0632]

[0633] Under a nitrogen stream, to a 1-methyl-2-pyrrolidone solution (10 mL) of 3,6-diphenylcarbazole (0.66 g, 2.06 mmol) and potassium carbonate (0.43 g, 3.11 mmol) was added the compound b (0.45 g, 0.825 mmol) obtained in Synthesis Example 9, and the mixture was stirred at 100 °C for 48 hours. The mixture was returned to room temperature and quenched by adding water, extracted with ethyl acetate, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the obtained mixture was purified by silica gel column chromatography (chloroform:hexane = 1:1) to obtain the compound 38 as a yellow solid (0.575 g, 0.502 mmol, yield 60.9%).

[0634] 1 1H-NMR (500 MHz, CDCl3, δ): 7.81 (d, J = 1.5 Hz, 4H), 7.72 - 7.70 (m, 4H), 7.54 - 7.52 (m, 8H), 7.43 (t, J = 7.5 Hz, 8H), 7.32 (t, J = 7.5 Hz, 4H), 7.29 - 7.06 (m, 20H), 6.86 - 6.83 (m, 2H), 6.61 - 6.58 (m, 1H), 6.56 - 6.52 (m, 2H)

[0635] ASAP mass spectrometry: theoretical value 1143.4, observed value 1143.4

[0636] (Synthesis Example 11) Synthesis of compound 48

[0637] [Chemical formula 76]

[0638]

[0639] Under a nitrogen stream, to a tetrahydrofuran solution (10 mL) of sodium hydride (60% mineral oil dispersion, 0.315 g, 7.88 mmol) was added 3,6-diphenylcarbazole (0.95 g, 2.97 mmol), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to -50 °C and the compound a (0.3 g, 1.19 mmol) obtained in Synthesis Example 9 was added. The cooling bath was removed and the mixture was stirred for 17 hours while gradually returning to room temperature. The reaction mixture was quenched by adding it to ice water, extracted with ethyl acetate, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the obtained mixture was purified by silica gel column chromatography (chloroform:hexane = 1:2) to obtain the compound c as a yellow solid (0.308 g, 0.362 mmol, yield 30.4%) and the compound d as a yellow solid (0.70 g, 0.609 mmol, yield 51.2%).

[0640] Compound c:

[0641] 1 H-NMR (500 MHz, CDCl3, δ): 8.42 (d, J = 1.0 Hz, 4H), 7.80 (dd, J = 7.0 Hz, 2.0 Hz, 4H), 7.74 (dd, J = 8.0 Hz, 1.0 Hz, 8H), 7.68 - 7.65 (m, 2H), 7.58 - 7.48 (m, 11H), 7.42 (d, J = 8.0 Hz, 4H), 7.40 - 7.36 (m, 4H)

[0642] ASAP mass spectrometry: Theoretical value 849.3, Observed value 849.3

[0643] Compound d:

[0644] 1 H-NMR (500 MHz, CDCl3, δ): 8.47 (d, J = 1.5 Hz, 2H), 7.89 (dd, J = 8.5 Hz, 2.0 Hz, 2H), 7.83 (d, J = 1.5 Hz, 2H), 7.80 - 7.78 (m, 4H), 7.74 (d, J = 1.5 Hz, 2H),

[0645] 7.66 (d, J = 8.0 Hz, 2H), 7.54 - 7.52 (m, 4H), 7.48 - 7.44 (m, 8H), 7.42 - 7.27 (m, 18H), 7.19 - 7.16 (m, 7H), 7.01 (d, J = 8.0 Hz, 2H)

[0646] ASAP mass spectrometry: Theoretical value 1148.4, Observed value 1148.4

[0647] [Chemical formula 77]

[0648]

[0649] Under a nitrogen stream, to a 1-methyl-2-pyrrolidone solution (10 mL) of 9H-carbazole (0.175 g, 1.05 mmol) and potassium carbonate (0.184 g, 1.33 mmol) was added Compound c (0.30 g, 0.35 mmol), and the mixture was stirred at 100 °C for 20 hours. The mixture was returned to room temperature and quenched by adding water, extracted with ethyl acetate, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the obtained mixture was purified by silica gel column chromatography (chloroform:hexane = 1:2) to obtain Compound 48 as a yellow solid (0.317 g, 0.277 mmol, yield 79.1%).

[0650] 1 H-NMR (500 MHz, CDCl₃, δ): 7.96 (d, J = 1.5 Hz, 4H), 7.59 - 7.55 (m, 12H), 7.45 (t, J = 7.5 Hz, 8H), 7.35 - 7.31 (m, 12H), 7.07 - 7.01 (m, 4H), 7.00 - 6.94 (m, 8H), 6.76 - 6.74 (m, 2H), 6.58 - 6.54 (m, 1H), 6.45 (t, J = 8.0 Hz, 2H)

[0651] ASAP mass spectrometry: Theoretical value 1143.4, Observed value 1143.3

[0652] (Synthesis Example 12) Synthesis of Compound 55

[0653] [Chemical Formula 78]

[0654]

[0655] Under a nitrogen stream, 9H-carbazole (4.78 g, 28.59 mmol) was added to a tetrahydrofuran solution (120 mL) of sodium hydride (60% mineral oil dispersion, 0.90 g, 22.51 mmol), and the mixture was stirred for 1 hour. The mixture was cooled to -50 °C and 2,3,5,6-tetrafluorobenzonitrile (2.50 g, 14.28 mmol) was added. The cooling bath was removed and the mixture was stirred for 110 hours while gradually returning to room temperature. The reaction mixture was quenched by adding it to ice water, extracted with ethyl acetate, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the obtained mixture was purified by silica gel column chromatography (toluene:hexane = 1:1) to obtain a pale yellow solid compound e (2.42 g, 5.15 mmol, yield 36.1%).

[0656] 1 H-NMR (500 MHz, CDCl₃, δ): 8.16 (d, J = 7.5 Hz, 4H), 7.68 (t, J H-F = 9.0 Hz, 1H), 7.51 (dt, J = 7.5 Hz, 1.0 Hz, 4H), 7.38 (dt, J = 7.5 Hz, 1.0 Hz, 4H), 7.23 (d, J = 7.5 Hz, 4H),

[0657] ASAP mass spectrometry: Theoretical value 469.1, Observed value 469.1

[0658] Under a nitrogen stream, to a 1-methyl-2-pyrrolidone solution (9 mL) of 3,6-diphenylcarbazole (0.57 g, 1.81 mmol) and potassium carbonate (0.38 g, 2.75 mmol) was added compound e (0.34 g, 0.724 mmol), and the mixture was stirred at 100 °C for 24 hours. The mixture was returned to room temperature and quenched by adding water, extracted with ethyl acetate, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the obtained mixture was purified by silica gel column chromatography (toluene:hexane = 1:1) to obtain compound 55 as a yellow solid (0.515 g, 0.482 mmol, yield 66.6%).

[0659] 1 H-NMR (500 MHz, CDCL3, δ): 8.54 (s, 1H), 8.04 (s, 4H), 7.81 (d, J = 7.5 Hz, 4H), 7.61 - 7.59 (m, 8H), 7.47 - 7.39 (m, 20H), 7.36 - 7.33 (m, 4H), 7.25 - 7.22 (m, 4H), 7.18 - 7.15 (m, 4H)

[0660] ASAP mass spectrometry: Theoretical value 1067.4, Observed value 1067.4

[0661] (Synthesis Example 13) Synthesis of Compound 108

[0662] [Chemical Formula 79]

[0663]

[0664] 1.56 g (9.00 mmol) of 3,6-dimethyl-9H-carbazole and 0.400 g (60% mineral oil dispersion, 1.00 mmol) of sodium hydride were placed in a 100 mL three-necked flask, and the flask was purged with nitrogen. After adding 80 mL of dehydrated tetrahydrofuran to the mixture, it was stirred under a nitrogen atmosphere for 1 hour, and then 0.8 g (4.00 mmol) of tetrafluoroterephthalonitrile was added. After heating and stirring the mixture at 50 °C for 12 hours, it was returned to room temperature, then water was added and suction filtration was carried out to obtain a solid. As a result of purifying the obtained solid by sublimation, compound f as a red solid was obtained (Yield: 0.8 g, Yield: 36%).

[0665] Into a 100 mL three-necked flask, 0.696 g (2.18 mmol) of 3,6-diphenyl-9H-carbazole, 0.647 g (3.63 mmol) of potassium carbonate, and 0.4 g (0.726 mmol) of compound f were added, and the flask was purged with nitrogen. After adding 10 mL of dehydrated 1-methyl-2-pyrrolidone to the mixture, it was heated and stirred at 100 °C for 12 hours under a nitrogen atmosphere. After stirring, the mixture was returned to room temperature, water was added, and suction filtration was carried out. As a result of recrystallizing the obtained solid with a mixed solvent of chloroform and acetonitrile, red solid compound 108 was obtained (yield: 0.62 g, yield rate: 74%).

[0666] 1 H NMR (500 MHz, CDCL3, δ): 8.01 (d, J = 1.5 Hz, 4H), 7.62 (dd, J = 8.0 Hz, J = 1.0 Hz, 8H), 7.50 - 7.43 (m, 12H), 7.41 (dd, J = 7.5, J = 1.5, 4H), 7.37 (t, J = 7.5, 4H), 7.33 (d, J = 8.5 Hz, 4H), 7.17 (d, J = 8 Hz, 4H), 6.99 (dd, J = 8 Hz, J = 1.5 Hz, 4H), 2.41 (s, 12H)

[0667] ASAP mass spectrometry analysis: theoretical value 1148.46, observed value 1150.51

[0668] (Synthesis Example 14) Synthesis of Compound 149

[0669] [Chemical Formula 80]

[0670]

[0671] Under a nitrogen stream, to a solution of 9H-carbazole (0.142 g, 0.849 mmol) and potassium carbonate (0.18 g, 1.30 mmol) in 1-methyl-2-pyrrolidone (10 mL), compound d (0.65 g, 0.566 mmol) was added, and it was stirred at 100 °C for 120 hours. The mixture was returned to room temperature and quenched by adding water. The obtained precipitate was washed with methanol and purified by silica gel column chromatography (toluene:hexane = 3:2) to obtain orange solid compound 149 (0.284 g, 0.219 mmol, yield rate 38.7%).

[0672] 1H-NMR (500 MHz, CDCl3, δ): 7.98 (d, J = 1.0 Hz, 2H), 7.85 (d, J = 1.0 Hz, 2H), 7.73 (d, J = 2.0 Hz, 2H), 7.60 - 7.58 (m, 6H), 7.49 - 7.44 (m, 12H), 7.39 - 7.24 (m, 20H), 7.19 - 7.16 (m, 4H), 7.12 - 7.09 (m, 2H), 7.05 - 6.97 (m, 6H), 6.93 (d, J = 8.0 Hz, 2H), 6.64 (t, J = 8.0 Hz, 1H), 6.58 (t, J = 8.0 Hz, 2H)

[0673] ASAP mass spectrometry: theoretical value 1295.5, observed value 1295.2

[0674] (Synthesis Example 15) Synthesis of Compound 150

[0675] [Chemical Formula 81]

[0676]

[0677] Under a nitrogen stream, to a 1-methyl-2-pyrrolidone solution (10 mL) of 3-methyl-9H-carbazole (0.57 g, 3.20 mmol) and potassium carbonate (0.95 g, 5.33 mmol) was added Compound e (0.50 g, 1.07 mmol), and the mixture was stirred at 120 °C for 36 hours. The mixture was returned to room temperature and water was added to cause precipitation, and the precipitate was then filtered. The filtered mixture was purified by silica gel column chromatography (toluene) to obtain Compound A (0.40 g, 0.51 mmol, yield 47.4%).

[0678] 1 H-NMR (500 MHz, CDCl3, δ): 8.38 (s, 1H), 7.83 - 7.79 (m, 4H), 7.75 - 7.72 (m, 2H), 7.58 (d, J = 4.0 Hz, 2H), 7.43 - 7.33 (m, 4H), 7.30 - 7.11 (m, 12H), 7.10 - 7.03 (m, 4H), 7.00 - 6.93 (m, 2H), 2.41 (s, 3H), 2.39 (s, 3H)

[0679] ASAP mass spectrometry: theoretical value 791.3, observed value 792.4

[0680] (Synthesis Example 16) Synthesis of Compound 151

[0681] [Chemical Formula 82]

[0682]

[0683] Under an argon stream, 4-bromo-2,3,5,6-tetrafluorobenzonitrile (3 g, 11.9 mmol) was dissolved in toluene (100 ml), and an aqueous solution of sodium carbonate (0.3 M, 67 ml) was added. Pd(PPh3)4 (1.38 g, 1.19 mmol) and 5'-m-tetraphenylboronic acid (3.92 g, 14.3 mmol) were added, and the mixture was heated under reflux overnight. After cooling to room temperature, the organic layer was separated, and the aqueous layer was extracted with dichloromethane. The organic layer was collected and dried over anhydrous sodium sulfate. The desiccant was filtered off, and the filtrate was concentrated by distillation under reduced pressure to obtain a crude product. The obtained crude product was purified by silica gel chromatography (hexane:chloroform = 4:1) to obtain compound i as a white powder (2.37 g, 5.88 mmol, 49.4%).

[0684] Under an argon stream, 9H-carbazole (0.83 g, 4.96 mmol) was added to a solution of sodium hydride (60% mineral oil dispersion, 0.2 g, 4.96 mmol) in tetrahydrofuran (50 ml), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to -50 °C, and compound i (1.0 g, 2.48 mmol) was added. The cooling bath was removed, and the mixture was stirred for 2 hours while gradually returning to room temperature. The reaction mixture was quenched by adding it to ice water, extracted with dichloromethane, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the obtained mixture was purified by silica gel column chromatography (hexane:toluene = 3:2) to obtain compound j as a white solid (0.96 g, 1.38 mmol, 55.6%).

[0685] Under an argon stream, 3,6-diphenylcarbazole (1.32 g, 4.14 mmol) was added to a solution of sodium hydride (60% mineral oil dispersion, 0.17 g, 4.14 mmol) in tetrahydrofuran (30 ml), and the mixture was stirred at room temperature for 1 hour. Compound 2 (0.96 g, 1.38 mmol) was added, and the mixture was heated at 50 °C overnight. The reaction mixture was quenched by adding it to ice water, and the solid was recovered. The obtained solid was purified by silica gel column chromatography (toluene) to obtain compound 151 as a yellow solid (1.10 g, 0.85 mmol, 61.5%).

[0686] (Synthesis Example 17) Synthesis of Compound 152

[0687] [Chemical Formula 83]

[0688]

[0689] Under a nitrogen stream, 9H-carbazole (0.80 g, 4.78 mmol) was added to a solution of sodium hydride (60% mineral oil dispersion, 0.17 g, 7.17 mmol) in tetrahydrofuran (15 mL), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to -50 °C and compound 1 (0.4 g, 1.59 mmol) was added. The cooling bath was removed, and the mixture was stirred for 24 hours while gradually returning to room temperature. The reaction mixture was quenched by adding it to ice water, extracted with ethyl acetate, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the resulting mixture was purified by silica gel column chromatography (hexane:toluene = 2:1) to obtain compound h as a yellow solid (0.69 g, 1.00 mmol, yield 62.9%).

[0690] 1 H-NMR (500 MHz, CDCL3, δ): 8.20 (d, J = 8.5 Hz, 2H), 7.72 - 7.68 (m, 2H), 7.61 - 7.56 (m, 4H), 7.51 (d, J = 8.5 Hz, 2H), 7.44 (t, J = 8.5 Hz, 2H), 7.16 - 7.11 (m, 4H), 7.10 - 6.94 (m, 13H)

[0691] ASAP mass spectrometry: Theoretical value 692.2, Observed value 692.1

[0692] Under a nitrogen stream, compound h (0.50 g, 0.72 mmol) was added to a solution of 3,6-diphenylcarbazole (0.35 g, 1.08 mmol) and potassium carbonate (0.20 g, 1.44 mmol) in 1-methyl-2-pyrrolidone (10 mL), and the mixture was stirred at 100 °C for 48 hours. The mixture was returned to room temperature and quenched by adding water, and the resulting precipitate was washed with methanol. It was reprecipitated with chloroform / methanol to obtain compound 3 as a yellow solid (0.56 g, 0.564 mmol, yield 77.6%).

[0693] 11H-NMR (500 MHz, CDCl3, δ): 7.80 (d, J = 1.5 Hz, 2H), 7.73 - 7.68 (m, 4H), 7.59 - 7.57 (m, 2H), 7.52 (dd, J = 8.0 Hz, J = 1.5 Hz, 4H), 7.42 (t, J = 8.0 Hz, 4H), 7.33 - 7.22 (m, 6H), 7.19 (dd, J = 8.0 Hz, J = 1.5 Hz, 2H), 7.14 - 6.92 (m, 16H), 6.74 (dd, J = 8.0 Hz, J = 1.5 Hz, 2H), 6.55 (t, J = 8.0 Hz, 1H), 6.48 (t, J = 8.0 Hz, 2H)

[0694] ASAP mass spectrometry: theoretical value 991.4, observed value 991.8

[0695] (Synthesis Example 18) Synthesis of Compound 313

[0696] [Chemical Formula 84]

[0697]

[0698] Under a nitrogen stream, 9H-carbazole (1.42 g, 8.49 mmol) was added to a solution of sodium hydride (60% mineral oil dispersion, 0.265 g, 6.63 mmol) in tetrahydrofuran (45 mL), and the mixture was stirred at room temperature for 1 hour. The mixture was cooled to -50 °C and 2,3,5,6-tetrafluoro-4-pyridinecarbonitrile (0.749 g, 4.25 mmol) was added. The cooling bath was removed and the mixture was stirred for 24 hours while gradually returning to room temperature. The reaction mixture was quenched by adding it to ice water, extracted with ethyl acetate, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the resulting mixture was reprecipitated with ethyl acetate / methanol to obtain Compound g as an orange solid (0.989 g, 2.10 mmol, yield 49.4%).

[0699] 1 1H-NMR (500 MHz, CDCl3, δ): 8.19 (d, J = 7.5 Hz, 2H), 8.15 (d, J = 7.5 Hz, 2H), 7.69 - 7.67 (m, 2H), 7.54 (dt, J = 7.5, 1.0 Hz, 4H), 7.44 (dt, J = 7.5, 1.5 Hz, 4H), 7.30 (d, J = 8.0 Hz, 2H)

[0700] 1313C-NMR (125 MHz, CDCl3, δ): 154.66, 154.64, 152.67, 152.65, 150.66, 150.62, 148.47, 148.43, 139.63, 138.59, 126.80, 126.76, 125.14, 124.55, 122.71, 122.14, 120.98, 120.54, 120.02, 119.75, 115.74, 115.69, 115.62, 115.57, 111.53, 111.50, 109.74, 108.76, 108.73

[0701] ASAP mass spectrometry: theoretical value 470.1, observed value 470.1

[0702] Under a nitrogen stream, to a 1-methyl-2-pyrrolidone solution (13 mL) of 3,6-diphenylcarbazole (0.849 g, 2.66 mmol) and potassium carbonate (0.55 g, 3.99 mmol) was added compound g (0.50 g, 1.06 mmol), and the mixture was stirred at 100 °C for 48 hours. The mixture was returned to room temperature and quenched by adding water, extracted with ethyl acetate, washed with saturated brine for the organic layer, and dried over anhydrous magnesium sulfate. It was concentrated under reduced pressure, and the obtained mixture was purified by silica gel column chromatography (toluene:hexane = 1:1) to obtain compound 313 as an orange solid (0.963 g, 0.901 mmol, yield 84.7%).

[0703] 1 1H-NMR (500 MHz, CDCl3, δ): 8.07 (d, J = 1.5 Hz, 2H), 8.00 (d, J = 1.5 Hz, 2H), 7.84 (d, J = 7.0 Hz, 2H), 7.76 (d, J = 7.0 Hz, 2H), 7.63 (d, J =8.0 Hz, 4H), 7.58 (d, J = 8.0 Hz, 4H), 7.54 - 7.43 (m, 14H), 7.38 - 7.32 (m, 8H), 7.30 - 7.07 (m, 10H)

[0704] ASAP mass spectrometry: theoretical value 1068.4, observed value 1068.3

[0705] ΔE st Measurement of

[0706] The lowest excited singlet state energy level E of the synthesized compound was determined by the following steps S1 and the lowest excited triplet state energy level E T1 . And, regarding the energy difference ΔE between the lowest excited singlet state and the lowest excited triplet state at 77 K st, by calculating the difference between E S1 and E T1 .

[0707] (1) The lowest singlet excited state energy level E S1

[0708] A sample was prepared by evaporating the compound to be measured on a Si substrate, and the fluorescence spectrum of the sample was measured at room temperature (300 K). In the fluorescence spectrum, the vertical axis was set to emission and the horizontal axis was set to wavelength. A tangent was drawn to the decline on the short-wavelength side of the emission spectrum, and the wavelength value λedge [nm] of the intersection of the tangent and the horizontal axis was obtained. This wavelength value was converted into an energy value using the conversion formula shown below, and the obtained value was used as E S1 .

[0709] Conversion formula: E S1 [eV] = 1239.85 / λedge

[0710] For the measurement of the emission spectrum, a nitrogen laser (manufactured by LTB Lasertechnik Berlin GmbH, MNL200) was used as the excitation light source and a streak camera (manufactured by Hamamatsu Photonics K.K., C4334) was used as the detector.

[0711] (2) The lowest triplet excited state energy level E T1

[0712] The same sample as the singlet energy E S1 was cooled to 77 [K], the excitation light (337 nm) was irradiated onto the sample for phosphorescence measurement, and the phosphorescence intensity was measured using a streak camera. A tangent was drawn to the rise on the short-wavelength side of the phosphorescence spectrum, and the wavelength value λedge [nm] of the intersection of the tangent and the horizontal axis was obtained. This wavelength value was converted into an energy value using the conversion formula shown below, and the obtained value was used as E T1 .

[0713] Conversion formula: E T1 [eV] = 1239.85 / λedge

[0714] The tangent to the rise on the short-wavelength side of the phosphorescence spectrum was drawn as follows. Considering moving from the short-wavelength side of the phosphorescence spectrum to the maximum value on the shortest-wavelength side of the spectral maximum on the spectral curve, the tangents at each point on the curve toward the long-wavelength side were considered. As the curve rises (i.e., as the vertical axis increases), the slope of this tangent increases. The tangent drawn at the point where the value of this slope takes the maximum value was set as the tangent to the rise on the short-wavelength side of the phosphorescence spectrum.

[0715] In addition, the maximum points of the peak intensities that are 10% or less of the maximum peak intensity of the spectrum are not included in the maximum value on the shortest wavelength side described above. The tangent line drawn at the point where the value of the slope takes the maximum value closest to the maximum value on the shortest wavelength side is set as the tangent line for the rise on the short wavelength side of the phosphorescence spectrum.

[0716] ΔE measured for each compound st As shown in the following table.

[0717] [Table 10]

[0718]

[0719] Fabrication and Evaluation of Organic Electroluminescent Devices

[0720] (Example 1)

[0721] By the vacuum evaporation method, each thin film was laminated on a glass substrate having an anode formed of indium / tin oxide (ITO) with a film thickness of 110 nm under a vacuum of 5.0×10 -5 Pa or less. First, HATCN was formed on the ITO with a thickness of 60 nm, TrisPCz was formed thereon with a thickness of 30 nm, and mCBP was formed thereon with a thickness of 5 nm. Then, mCBP, Compound 1, and TBPb were co-evaporated from different evaporation sources to form a layer with a thickness of 30 nm, which was set as the light-emitting layer. At this time, the concentration of Compound 1 was set to 20% by weight, and the concentration of TBPb was set to 0.5% by weight. Then, SF3TRZ was formed with a thickness of 10 nm, and SF3TRZ:Liq (weight ratio 7:3) was formed thereon with a thickness of 30 nm. Moreover, a cathode was formed by evaporating Liq:Al (weight ratio 1:50) to obtain an organic electroluminescent element, which was designated as Element 1.

[0722] As shown in the following table, by changing the concentration of the second organic compound in the light-emitting layer, or using Compound A (ΔE st = 0.17 eV) to replace Compound 1 in the light-emitting layer, or using DPEPO to replace mCBP in the light-emitting layer for manufacturing, Elements 2 to 8 were also fabricated.

[0723] These Elements 1 to 8 all emit delayed fluorescence, at the maximum emission wavelength and 0.01 mA / cm 2The external quantum efficiency under the conditions is shown in the following table. Compared with the comparative elements that only use the corresponding amount of the first organic compound without using the second organic compound in the light-emitting layer, the external quantum efficiency is significantly improved. In particular, as the second organic compound, compared with Elements 2, 4, 6, and 8 that use Compound A in which all five carbazol-9-yl groups bonded to benzonitrile are the same, Elements 1, 3, 5, and 7 that use Compound 1 in which all five carbazol-9-yl groups bonded to benzonitrile are not the same further greatly improve the external quantum efficiency.

[0724] [Table 11]

[0725]

[0726] (Example 2)

[0727] By the vacuum evaporation method, each thin film was laminated on a glass substrate having an anode formed of indium / tin oxide (ITO) with a film thickness of 110 nm under a vacuum of 5.0×10 -5 Pa or less. First, HATCN was formed on the ITO with a thickness of 10 nm, TrisPCz was formed thereon with a thickness of 25 nm, and mCBP was formed thereon with a thickness of 5 nm. Then, mCBP, Compound 3, and TTPA were co-evaporated from different evaporation sources to form a layer with a thickness of 30 nm, which was set as the light-emitting layer. At this time, the concentration of Compound 3 was set to 20% by weight, and the concentration of TTPA was set to 0.5% by weight. Then, SF3TRZ was formed with a thickness of 10 nm, and SF3TRZ:Liq (weight ratio 7:3) was formed thereon with a thickness of 40 nm. Moreover, a cathode was formed by evaporating Liq:Al (weight ratio 1:50) to obtain an organic electroluminescent element, which was set as Element 9.

[0728] As shown in the following table, by using Compound A instead of Compound 3 in the light-emitting layer, or using 2DPhAPA instead of TTPA in the light-emitting layer for manufacturing, Elements 10 to 12 were also fabricated.

[0729] These Elements 9 to 12 all emit delayed fluorescence, at the maximum emission wavelength, 0.01 mA / cm 2 and 1000 cd / m 2The external quantum efficiency under the conditions is shown in the following table. Compared with the comparative elements that use only the corresponding amount of the first organic compound without using the second organic compound in the light-emitting layer, the external quantum efficiency and the lifetime are also significantly improved. In particular, as the second organic compound, compared with Element 10 that uses Compound A in which all five carbazol-9-yl groups bonded to benzonitrile are the same, Element 9 that uses Compound 3 in which all five carbazol-9-yl groups bonded to benzonitrile are not the same further significantly improves the external quantum efficiency and the lifetime. The same trend is also observed in Element 12 that uses Compound A and Element 11 that uses Compound 3.

[0730]

[0731] The organic electroluminescent element that uses Compounds 2, 4 to 7, 11, 35, 38, 48, 55, 108, 149, 150, 151, 152, 313, Compound b, and Compound d to replace Compound 1 of Element 1 also has the same excellent external quantum efficiency and lifetime as Element 1.

[0732] [Chemical formula 85-1]

[0733]

[0734] [Chemical formula 85-2]

[0735]

[0736] (Example 3)

[0737] The combinations of the second organic compound and the third organic compound in the light-emitting layer of Element 1 are respectively replaced with the combinations 1 to 16950 of the second organic compound and the third organic compound described in Table 9 to manufacture an organic electroluminescent element, and the organic electroluminescent elements are respectively designated as Elements 1a to 16950a.

[0738] The combinations of the second organic compound and the third organic compound in the light-emitting layer of Element 9 are respectively replaced with the combinations 1 to 16950 of the second organic compound and the third organic compound described in Table 9 to manufacture an organic electroluminescent element, and the organic electroluminescent elements are respectively designated as Elements 1b to 16950b.

[0739] (Example 4)

[0740] Compared with Elements 1B to 1K manufactured by using the following Compounds B to K to replace Compound 1 of Element 1 respectively, Element 1 significantly improves the external quantum efficiency and the lifetime.

[0741] Moreover, compared with elements 9B to 9K manufactured by using compounds B to K below to replace compound 3 of element 9 respectively, element 9 significantly improves heat resistance and lifespan.

[0742] [Chemical formula 86-1]

[0743]

[0744] [Chemical formula 86-2]

[0745]

[0746] Industrial applicability

[0747] The organic electroluminescent element of the present invention can achieve high luminous efficiency, and thus can be applied to various devices as an image display device. Therefore, the industrial applicability of the present invention is high.

[0748] Symbol description

[0749] 1 - Substrate, 2 - Anode, 3 - Hole injection layer, 4 - Hole transport layer, 5 - Light emitting layer, 6 - Electron transport layer, 7 - Cathode.

Claims

1. An organic electroluminescent element having an anode, a cathode, and at least one organic layer including a light-emitting layer between the anode and the cathode, wherein the organic electroluminescent element is characterized in that, the light-emitting layer contains at least a first organic compound, a second organic compound, and a third organic compound satisfying the following formula (A), the second organic compound being a delayed phosphor which is a compound represented by the following general formula (10), and the third organic compound being a light-emitting body, Formula (A) E S1 (A) > E S1 (B) > E S1 (C) In the above formula, E S1 (A) represents the lowest excited singlet state energy level of the first organic compound, E S1 (B) represents the lowest excited singlet state energy level of the second organic compound, E S1 (C) represents the lowest excited singlet state energy level of the third organic compound; General formula (10) In general formula (10), A 1 represents a cyano group, and R 1 to R 5 each independently represents a phenyl group or a group represented by the following general formula (2) in which the Hammett σp value is negative, and 2 to 4 of R 1 to R 5 are groups represented by the following general formula (2) in which the Hammett σp value is negative. The number of substituents substituting on the aromatic ring of the carbazole structure in general formula (2) represented by these general formula (2) is different from each other. The substituents substituting on the aromatic ring include a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 40 carbon atoms; two of the substituents substituting on the aromatic ring may combine with each other to form a ring, and all hydrogen atoms in the molecule are 1 H or a part or all of them are 2 H, that is, deuterium D; General formula (2) In general formula (2), R 11 ~R 18 each independently represents a hydrogen atom or a substituent, and R 19 is the bonding position to the benzene ring.

2. The organic electroluminescent element according to claim 1, wherein The energy difference ΔEs between the lowest excited singlet state of the second organic compound and the lowest excited triplet state at 77K t is 0.3 eV or less.

3. The organic electroluminescent element according to claim 1, wherein The energy difference ΔEs between the lowest excited singlet state of the second organic compound and the lowest excited triplet state at 77K t is 0.08 eV or less.

4. The organic electroluminescent element according to claim 1, wherein the first organic compound and the second organic compound satisfy the following formula (B), Formula (B) E T1 (A) > E T1 (B) In the above formula, E T1 (A) represents the lowest excited triplet state energy level of the first organic compound at 77 K, and E T1 (B) represents the lowest excited triplet state energy level of the second organic compound at 77 K.

5. The organic electroluminescent element according to claim 1, wherein the third organic compound emits fluorescence when returning from the lowest excited singlet energy level to the ground state energy level.

6. The organic electroluminescent element according to claim 1, wherein the content of the second organic compound in the light-emitting layer is less than the content of the first organic compound.

7. The organic electroluminescent element according to claim 1, wherein the light-emitting layer contains two or more compounds as the third organic compound.

8. The organic electroluminescent element according to claim 1, wherein the light-emitting layer contains one or two or more organic compounds in addition to the first organic compound, the second organic compound, and the third organic compound.

9. The organic electroluminescent element according to claim 1, wherein, R 1 ~R 5 Four of them are the groups represented by the general formula (2) with a negative Hammett σp value.

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