Light-emitting material, long-lasting phosphor, organic light-emitting diode, screen, display, and display manufacturing method

Abstract

A light emitting material which contains an adjustment compound N in addition to a donor compound D and an acceptor compound A, said compounds D and A forming an exciplex, and which satisfies HOMO(D) > HOMO(N) > HOMO(A), LUMO(D) > LUMO(N) + 0.1 eV and LUMO(N) > LUMO(A), has improved luminous efficiency or improved emission lifetime.

Description

[Technical field]

[0001] The present invention relates to a luminescent material having improved luminous efficiency or luminescent lifetime. The present invention also relates to a delayed phosphor, an organic light-emitting diode, a screen and a display using such a luminescent material. The present invention also relates to a method for producing a display. [Background technology]

[0002] Research into improving the luminous efficiency of light-emitting elements has been actively conducted. In particular, various researches have been conducted into developing new luminescent materials to efficiently emit light. Among them, luminescent materials using exciplexes combining an acceptor compound and a donor compound have an energy difference ΔE between the excited triplet energy level and the excited singlet energy level by combining an appropriate acceptor compound and a donor compound, which is smaller than that of luminescent materials having an acceptor and a donor in the same molecule. st This has the potential to reduce the amount of phosphorescence, and its use as a delayed fluorescent material is being considered. For example, Patent Document 1 discloses a method for determining whether a mixture of an acceptor compound and a donor compound is capable of determining whether the triplet energy T1 of the acceptor compound is zero or not. A and |LUMO A | and the excited triplet energy T1 of the donor compound D and |HOMO D A delayed fluorescent material is proposed in which the magnitude and relationship of the excited singlet energy S1 of the exciplex is specified. In the document, it is confirmed that a high luminous efficiency is obtained in a light-emitting device using the delayed fluorescent material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-193352 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described in Patent Document 1, conventional luminescent materials that form exciplexes are provided as a mixture of a donor compound and an acceptor compound. In order to improve the luminescence efficiency and luminescence lifetime of luminescence involving exciplexes, studies have mainly been conducted so far on providing new combinations of donor compounds and acceptor compounds. However, in order to propose a new combination of a donor compound and an acceptor compound and actually confirm the effect, a huge amount of trial and error and experimentation is required. Furthermore, even if a promising combination of a donor compound and an acceptor compound is found as a result of such trial and error and experimentation, it cannot be put to practical use unless it clears conditions such as manufacturing cost, safety, and environmental compatibility. For this reason, it requires a large cost and time to improve the efficiency and lifetime of luminescence involving exciplexes and put it into practical use. In view of these circumstances, the present inventors have carried out investigations aimed at improving the efficiency and lifetime of exciplex-related luminescence by simple means. [Means for solving the problem]

[0005] As a result of extensive investigations, the inventors have found that the luminescence efficiency and luminescence lifetime of a light-emitting material can be improved by adding a coordinating compound that satisfies a specific energy relationship in addition to a donor compound and an acceptor compound that form an exciplex, and have thus provided the present invention. The present invention includes at least the following technical items. [1] A light-emitting material that contains, in addition to a donor compound and an acceptor compound that form an exciplex, a coordinating compound other than the donor compound and the acceptor compound, and that satisfies the relationships of the following formulas (A), (B1), and (B2). Formula (A) HOMO(D)>HOMO(N)>HOMO(A) Formula (B1) LUMO(D)>LUMO(N)+0.1eV Formula (B2) LUMO(N)>LUMO(A) [In formulae (A), (B1) and (B2), HOMO(D) represents the energy level of the HOMO (Highest Occupied Molecular Orbital) of the donor compound, HOMO(A) represents the energy level of the HOMO of the host material, HOMO(N) represents the energy level of the HOMO of the coordinating compound, LUMO(D) represents the energy level of the LUMO (Lowest Unoccupied Molecular Orbital) of the donor compound, LUMO(A) represents the energy level of the LUMO of the acceptor compound and LUMO(N) represents the energy level of the LUMO of the coordinating compound.] [2] The light-emitting material according to [1], further satisfying the relationship of the following formula (C): Formula (C) HOMO(D)≧HOMO(A)+0.6eV [3] The light-emitting material according to [1], further satisfying the relationships of the following formulae (D) and (E): Formula (D) T1(D) <T1(N) Formula (E) T1(A) <T1(N) [In formula (D) and formula (E), T1(D) represents the lowest excited triplet energy level of the donor compound, T1(A) represents the lowest excited triplet energy level of the acceptor compound, and T1(N) represents the lowest excited triplet energy level of the coordinating compound.] [4] The light-emitting material according to any one of [1] to [3], wherein the content of the adjusting compound is 30% by mass or more. [5] The luminescent material according to any one of [1] to [4], wherein the luminescence intensity from the exciplex is 10 times or more higher than the luminescence intensity from the coordinating compound. [6] The light-emitting material according to any one of [1] to [5], further comprising a light-emitting compound. [7] The luminescent material according to [6], wherein the luminescence intensity from the luminescent compound is 10 times or more higher than the luminescence intensity from the exciplex. [8] The luminescent material according to [6], wherein the luminescence intensity from the luminescent compound is 50 times or more higher than the luminescence intensity from the adjusting compound. [9] A persistent fluorescent material comprising the luminescent material according to any one of [1] to [8].

[10] An organic light-emitting diode (OLED) comprising the light-emitting material according to any one of [1] to [8].

[11] An organic light-emitting diode (OLED) comprising an anode, a cathode, and at least one organic layer comprising an emissive layer between the anode and the cathode, The light-emitting layer comprises the light-emitting material according to any one of [1] to [8].

[12] An organic light-emitting diode (OLED) comprising an anode, a cathode, and at least one organic layer comprising an emissive layer between the anode and the cathode, The light-emitting layer comprises the light-emitting material according to any one of [6] to [8].

[13] A screen or display comprising the light-emitting material according to any one of [1] to [8].

[14] A method of making an OLED display, the method comprising: forming a barrier layer on a base substrate of a mother panel; forming a plurality of display units on the barrier layer in units of cell panels; forming an encapsulation layer over each of the display units of the cell panel; applying an organic film to the interface between the cell panels; The organic film contains the light-emitting material according to any one of [1] to [8]. method. Effect of the Invention

[0006] According to the present invention, it is possible to provide a light-emitting material involving exciplexes, which has at least one of improved luminous efficiency and luminous lifetime. Also, according to the present invention, it is possible to provide a delayed phosphor, an organic light-emitting diode, a screen, and a display, which have at least one of improved luminous efficiency and luminous lifetime. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic cross-sectional view showing an example of a layer structure of an organic electroluminescence device. [Diagram 2] FIG. 2 is a diagram showing the energy levels of each compound used in the light-emitting layer of Example 1. [Diagram 3] 1 shows the emission spectrum of each device in Example 1. [Figure 4] FIG. 1 shows the energy levels of each compound used in the light-emitting layer of Example 3. [Diagram 5] 1 shows the emission spectrum of each device in Example 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The contents of the present invention will be described in detail below. The following description of the constituent elements may be based on representative embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples. In this specification, a numerical range expressed using "~" means a range including the numerical values ​​before and after "~" as the lower and upper limits.

[0009] [Light-emitting material of the present invention] (Energy levels of each compound contained in the luminescent material) The light-emitting material of the present invention includes a donor compound that forms an exciplex, an acceptor compound that forms the exciplex, and a coordinating compound that is different from the donor compound and the acceptor compound. The donor compound, the acceptor compound, and the coordinating compound contained in the light-emitting material of the present invention satisfy the relationships of the following formulae (A), (B1), and (B2). Formula (A) HOMO(D)>HOMO(N)>HOMO(A) Formula (B1) LUMO(D)>LUMO(N)+0.1eV Formula (B2) LUMO(N)>LUMO(A) [In formula (A), formula (B1) and formula (B2), HOMO(D) represents the energy level of the HOMO of the donor compound, HOMO(A) represents the energy level of the HOMO of the host material, HOMO(N) represents the energy level of the HOMO of the coordinating compound, LUMO(D) represents the energy level of the LUMO of the donor compound, LUMO(A) represents the energy level of the LUMO of the acceptor compound and LUMO(N) represents the energy level of the LUMO of the coordinating compound. In the present invention, these energy levels are expressed in eV units.

[0010] The HOMO energy level and the LUMO energy level in the present invention are determined by photoelectron spectroscopy in air. In the present invention, the HOMO energy level and the LUMO energy level were measured using an AC-3 manufactured by Riken Keiki Co., Ltd.

[0011] HOMO(N) may be any value larger than HOMO(A) and smaller than HOMO(D). In one embodiment of the present invention, HOMO(N) is closer to HOMO(A) than to HOMO(D). In another embodiment of the present invention, HOMO(N) is closer to HOMO(D) than to HOMO(A). In another embodiment of the present invention, HOMO(N) is within the following range.

number

number

[0012] LUMO(N) may be larger than LUMO(A) and smaller than LUMO(D) by more than 0.1 eV. LUMO(N) is preferably smaller than LUMO(D) by more than 0.2 eV. In one embodiment of the present invention, LUMO(N) is smaller than LUMO(D) by more than 0.3 eV, and in another embodiment of the present invention, LUMO(N) is smaller than LUMO(D) by more than 0.4 eV. If LUMO(N) is smaller than LUMO(D) by more than 0.1 eV, higher luminous efficiency can be achieved. In one embodiment of the present invention, LUMO(N) is closer to LUMO(A) than LUMO(D). In another embodiment of the present invention, LUMO(N) is closer to LUMO(D) than LUMO(A). In another embodiment of the present invention, LUMO(N) is within the following range.

number

number

[0013] In one embodiment of the present invention, HOMO(D) and HOMO(A) satisfy the following formula: Formula (C) HOMO(D)≧HOMO(A)+0.6eV In another embodiment of the present invention, HOMO(D) and HOMO(A) satisfy the following formula: Formula (C1) HOMO(D)≧HOMO(A)+0.7eV In another embodiment of the present invention, HOMO(D) and HOMO(A) satisfy the following formula: Formula (C2) HOMO(D)≧HOMO(A)+0.8eV

[0014] The donor compound, acceptor compound and coordinating compound contained in the light-emitting material of the present invention preferably have the lowest excited triplet energy levels that satisfy the following formulae (D) and (E). Formula (D) T1(D) <T1(N) Formula (E) T1(A) <T1(N) In formula (D) and formula (E), T1(D) represents the lowest excited triplet energy level of the donor compound, T1(A) represents the lowest excited triplet energy level of the acceptor compound, and T1(N) represents the lowest excited triplet energy level of the coordinating compound. In one embodiment of the present invention, the lowest excited triplet energy level satisfies the following formula: Formula (D1) T1(D)+0.2eV <T1(N) Formula (E1) T1(A)+0.2eV <T1(N) In another embodiment of the present invention, the lowest excited triplet energy level satisfies the following formula: Formula (D2) T1(D)+0.4eV <T1(N) Formula (E2) T1(A)+0.4eV <T1(N) The lowest excited triplet energy level T1(N) of the adjusting compound contained in the luminescent material of the present invention may be, for example, −2.4 eV or less, −2.6 eV or less, or −2.8 eV or less, or may be, for example, −3.2 eV or more.

[0015] (Donor compounds contained in luminescent materials) The donor compound contained in the light-emitting material of the present invention is a compound that forms an exciplex together with an acceptor compound. In the present invention, a known donor compound that forms an exciplex can be used. In a preferred embodiment of the present invention, a donor compound having the following skeleton is employed: [ka]

[0016] The hydrogen atoms of the skeleton may be substituted with a substituent. The number of substituents may be 0, 1, 2, 3, or 4 or more. When substituted with two or more substituents, the substituents may be the same or different. The substituents are preferably selected from deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted amino, substituted or unsubstituted aryl, substituted or unsubstituted aryloxy, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroaryloxy, and silyl.

[0017] The molecular weight of the donor compound can be selected, for example, within the range of 200 or more, 250 or more, or 300 or more, or within the range of 2000 or less, 1000 or less, or 700 or less.

[0018] Specific examples of donor compounds are given below, but the donor compounds that can be used in the present invention should not be construed as being limited to these exemplary compounds. [ka]

[0019] (Acceptor compounds contained in luminescent materials) The acceptor compound contained in the light-emitting material of the present invention is a compound that forms an exciplex together with a donor compound. In the present invention, a known acceptor compound that forms an exciplex can be used. In a preferred embodiment of the present invention, an acceptor compound having the following skeleton is employed: [ka] The hydrogen atoms of the skeleton may be substituted with a substituent. The number of substituents may be 0, 1, 2, 3, or 4 or more. When substituted with two or more substituents, the substituents may be the same or different. The substituents are preferably selected from deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted amino, substituted or unsubstituted aryl, substituted or unsubstituted aryloxy, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroaryloxy, and silyl.

[0020] The molecular weight of the acceptor compound can be selected, for example, within the range of 200 or more, 250 or more, or 300 or more, or within the range of 2000 or less, 1000 or less, or 700 or less.

[0021] Specific examples of the acceptor compound are given below, but the acceptor compounds that can be used in the present invention should not be construed as being limited to these exemplary compounds. [ka] [ka]

[0022] In the light-emitting material of the present invention, a donor compound and an acceptor compound form an exciplex. An exciplex is an association of an acceptor compound and a donor compound, and when excitation energy is provided, an electronic transition occurs from the donor compound to the acceptor compound, converting it to an excited state. The light-emitting material of the present invention may emit light from an exciplex, or may emit light from a light-emitting compound when it further contains a light-emitting compound described later, or may emit light from both an exciplex and a light-emitting material. The exciplex is preferably one that emits light in the visible range, and may be one that emits light such as blue, green, yellow, or red. In addition, the exciplex is preferably one that emits delayed fluorescence, but may also be one that emits normal fluorescence. The difference ΔE between the lowest excited singlet energy and the lowest excited triplet energy of the exciplex ST is preferably 0.3 eV or less, more preferably 0.2 eV or less, even more preferably 0.1 eV or less, even more preferably 0.05 eV or less, and particularly preferably 0.02 eV or less. In one embodiment of the present invention, when the emission intensity from the light-emitting material is taken as 100%, the emission intensity from the exciplex may be adjusted to be, for example, within a range of 0.1% or more, 1% or more, 10% or more, 25% or more, 50% by mass or more, 75% or more, 90% or more, or 99% or more, or may be 100%. It may also be adjusted to be within a range of 95% or less, 70% or less, 40% or less, 30% or less, 10% or less, or 1% or less. In one embodiment of the present invention, the emission from other than the exciplex or the light-emitting compound may be adjusted to be within a range of 20% or less, 10% or less, 5% or less, 1% or less, 0.1% or less, or 0.01% or less, or may be 0%.

[0023] (Adjusting compounds contained in luminescent materials) The structure of the adjusting compound contained in the light emitting material of the present invention is not particularly limited as long as it satisfies the formula (A), the formula (B1) and the formula (B2). In one embodiment of the present invention, the adjusting compound is a compound having a donor site and an acceptor site in the molecule. When the donor site is D and the acceptor site is A, D.A. DAD DADAD ADA ADADA (A)mD (D)nA Examples include compounds having a structure represented by the following formula: When two or more Ds are present in a molecule, they may be the same or different from each other, and when two or more As are present in a molecule, they may be the same or different from each other. m represents an integer of 3 or more and up to the maximum number that D can replace, and n represents an integer of 3 or more and up to the maximum number that A can replace.

[0024] For the donor site D, a group having a negative Hammett σp value can be used. For the acceptor site A, a group having a positive Hammett σp value can be used. p The "para-substituted benzene derivative equilibrium constant" was proposed by L.P. Hammett and quantifies the effect of a substituent on the reaction rate or equilibrium of a para-substituted benzene derivative. Specifically, the following equation holds between the substituent in the para-substituted benzene derivative and the reaction rate constant or equilibrium constant: log(k / k0) = ρσ p or log(K / K0) = ρσ p The constants specific to the substituents in p In the above formula, k is the rate constant of the benzene derivative having no substituent, k0 is the rate constant of the benzene derivative substituted with a substituent, K is the equilibrium constant of the benzene derivative having no substituent, K0 is the equilibrium constant of the benzene derivative substituted with a substituent, and ρ is a reaction constant determined by the type and conditions of the reaction. p For the explanation of "value" and the numerical values ​​of each substituent, see σ of Hansch, C. et. al., Chem. Rev., 91, 165-195 (1991).p You can refer to the description of values.

[0025] In another embodiment of the present invention, the adjusting compound is a compound having two or more donor sites and linking groups connecting them in the molecule. For example, when the donor site is D and the linking groups are L and L', DLD DLDLD (D)n-L' Examples of compounds having a structure represented by the formula: When two or more D's are present in a molecule, they may be the same or different from each other, and when two or more L's are present in a molecule, they may be the same or different from each other. n represents an integer of 3 or more and not more than the maximum number of L's that can be substituted, and L' represents an n-valent linking group.

[0026] Examples of the linking groups L and L' include substituted or unsubstituted arylene groups, substituted or unsubstituted alkenylene groups, and substituted or unsubstituted alkynylene groups. Examples also include groups in which two or more groups selected from substituted or unsubstituted arylene groups, substituted or unsubstituted alkenylene groups, and substituted or unsubstituted alkynylene groups are linked together. The arylene group here may be selected from the range of 6 to 30 carbon atoms, 6 to 20 carbon atoms, 6 to 14 carbon atoms, and 6 to 10 carbon atoms, and specific examples include a 1,4-phenylene group, a 1,3-phenylene group, a 1,2-phenylene group, a 1,8-naphthylene group, a 1,4-naphthylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,6-naphthylene group, a 2,7-naphthylene group, a 9,10-anthracenylene group, a 2,3-anthracenylene group, a 2,6-anthracenylene group, a 2,7-anthracenylene group, a 1,8-anthracenylene group, and a 1,5-anthracenylene group. The alkenylene group referred to here may be selected from the range of carbon numbers of 2 to 20, 2 to 10, 2 to 6, and 2 to 4, for example. Specific examples include -(CR 1 =CR 2 ) n1 In particular, the group represented by R 1 and R2 each independently represents a hydrogen atom or a substituent, and examples of the substituent include an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and an aryl group having 6 to 30 carbon atoms. n1 is an integer from 1 to 10. The alkynylene group may be selected from the range of, for example, 2 to 20 carbon atoms, 2 to 10 carbon atoms, 2 to 6 carbon atoms, and 2 to 4 carbon atoms, and a specific example is an ethynylene group. Examples of the substituent of the arylene group and alkenylene group that the linking groups L and L' can take include an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and an aryl group having 6 to 30 carbon atoms.

[0027] The molecular weight of the adjusting compound can be selected, for example, within the range of 200 or more, 250 or more, 300 or more, or within the range of 2000 or less, 1000 or less, 700 or less.

[0028] Specific examples of the adjusting compounds are given below, but the adjusting compounds that can be used in the present invention should not be construed as being limited to these exemplary compounds. [ka]

[0029] (Luminescent Compounds) The light-emitting material of the present invention may contain a light-emitting compound as a compound other than the donor compound, the acceptor compound, and the coordinating compound. The light-emitting compound here does not correspond to the coordinating compound satisfying the formula (A), the formula (B1), and the formula (B2). The light-emitting compound contained in the light-emitting material of the present invention is preferably a compound that emits light by receiving energy from an exciplex formed by a donor compound and an acceptor compound. Two or more types of light-emitting compounds may be contained, and in this case, energy may be transferred from one light-emitting compound to another light-emitting compound, or energy may be transferred directly from the exciplex to each of the two or more light-emitting compounds. The light-emitting compound preferably emits light in the visible region, and may emit light of, for example, blue, green, yellow, red, etc. The light-emitting compound may also emit fluorescence or phosphorescence, or may emit delayed fluorescence. When the luminescent material of the present invention contains a luminescent compound, it may emit light only from the luminescent compound, or may emit light from the luminescent compound and other substances. In the latter case, the luminescence intensity from the luminescent compound may be the highest, or the luminescence intensity from the luminescent compound may be lower than the luminescence intensity from substances other than the luminescent compound (for example, an exciplex formed by a donor compound and an acceptor compound). The luminescence intensity from the luminescent material can be controlled by adjusting the type and content of the luminescent material. When the luminescence intensity from the luminescent material is taken as 100%, the luminescence intensity from the luminescent compound may be adjusted to be within the range of, for example, 0.1% or more, 1% or more, 10% or more, 25% or more, 50% by mass or more, 75% or more, 90% or more, or 99% or more. It may also be adjusted to be within the range of 95% or less, 70% or less, 40% or less, 30% or less, 10% or less, or 1% or less. The luminescence intensity from the luminescent compound may be 1.5 times or more, 2 times or more, 5 times or more, 10 times or more, or 100 times or more, or 0.5 times or less, 0.1 times or less, or 0.01 times or less, that from the exciplex. Also, the luminescence intensity from the luminescent compound may be 3 times or more, 10 times or more, 50 times or more, or 100 times or more, that from the coordinating compound. Examples of luminescent materials that can be used in the luminescent material of the present invention are given below, but the luminescent materials that can be used in the present invention are not limited to the following compounds. [ka]

[0030] (Composition of luminescent material) The content of each of the donor compound, acceptor compound, and coordinating compound contained in the luminescent material is not particularly limited as long as it is capable of luminescence. When the entire luminescent material is taken as 100 mass%, the content of each compound can be selected, for example, within the range of 0.01 to 99.99 mass%. Each compound may be independently selected, for example, from the range of 0.1 mass% or more, 1 mass% or more, 5 mass% or more, 10 mass% or more, 30 mass% or more, 50 mass% or more, 70 mass% or more, or 90 mass% or more, or may be selected from the range of 80 mass% or less, 60 mass% or less, 40 mass% or less, 20 mass% or less, 10 mass% or less, 5 mass% or less, or 1 mass% or less. In one embodiment of the present invention, the content of the coordinating compound is greater than the content of the donor compound and greater than the content of the acceptor compound. In one embodiment of the present invention, the content of the coordinating compound is equal to or greater than the combined content of the donor compound and the acceptor compound. In another embodiment of the present invention, the content of the coordinating compound is less than the total content of the donor compound and the acceptor compound. Also, in another embodiment of the present invention, the content of the coordinating compound is less than the content of the donor compound and less than the content of the acceptor compound. In the light-emitting material of the present invention, the content of the donor compound and the content of the acceptor compound may be the same, or the amount of the donor compound may be greater than the amount of the acceptor compound (for example, the amount of the donor compound may be at least 2 times, at least 4 times, or at least 10 times the amount of the acceptor compound), or the amount of the acceptor compound may be greater than the amount of the donor compound (for example, the amount of the acceptor compound may be at least 2 times, at least 4 times, or at least 10 times the amount of the donor compound). In the luminescent material of the present invention, the content of the donor compound and the content of the adjusting compound may be the same, or the amount of the donor compound may be greater than the amount of the adjusting compound (for example, the amount of the donor compound may be at least 2 times, at least 4 times, or at least 10 times the amount of the adjusting compound), or the amount of the adjusting compound may be greater than the amount of the donor compound (for example, the amount of the adjusting compound may be at least 2 times, at least 4 times, or at least 10 times the amount of the donor compound). In the luminescent material of the present invention, the content of the acceptor compound and the content of the adjusting compound may be the same, or the amount of the acceptor compound may be greater than the amount of the adjusting compound (for example, the amount of the acceptor compound may be at least 2 times, at least 4 times, or at least 10 times the amount of the adjusting compound), or the amount of the adjusting compound may be greater than the amount of the acceptor compound (for example, the amount of the adjusting compound may be at least 2 times, at least 4 times, or at least 10 times the amount of the acceptor compound).

[0031] In the light-emitting material of the present invention, by increasing the content of the adjusting compound, at least one of the light-emitting efficiency and the light-emitting lifetime tends to be improved. In addition, in the light-emitting material of the present invention, by increasing the content of the adjusting compound, the lifetime of delayed fluorescence tends to be extended.

[0032] When the luminescent material of the present invention contains a luminescent compound as a compound other than a donor compound, an acceptor compound, and a coordinating compound, the content may be selected from within the range of, for example, 0.01 mass% or more, 0.1 mass% or more, 1 mass% or more, 3 mass% or more, 5 mass% or more, 10 mass% or more, or 20 mass% or more, or may be selected from the range of 30 mass% or less, 15 mass% or less, 10 mass% or less, 5 mass% or less, or 1 mass% or less. In one embodiment of the present invention, the light emitting material of the present invention does not contain a light emitting compound, and among the light emissions from the light emitting material of the present invention, the light emission intensity from the exciplex formed between the donor compound and the acceptor compound is the greatest.

[0033] The light-emitting material of the present invention may contain a compound that does not fall under any of the donor compound, acceptor compound, coordinating compound, and light-emitting compound. The light-emitting material of the present invention may consist only of a donor compound, an acceptor compound, a coordinating compound, and a light-emitting compound.

[0034] (definition) Unless otherwise defined herein, scientific and technical terms used in this application have the meanings commonly understood by those of ordinary skill in the art. Generally, the nomenclature and techniques relating to the chemicals described herein are well known and commonly used in the art. The term "acyl" is art recognized and refers to a group represented by the general formula hydrocarbylC(O)-, preferably alkylC(O)-. The term "acylamino" is art recognized and refers to an amino group substituted with an acyl group and may be represented, for example, by the formula hydrocarbylC(O)NH-. The term "acyloxy" is art recognized and refers to a group represented by the general formula hydrocarbylC(O)O-, preferably alkylC(O)O-. The term "alkoxy" refers to an alkyl group having an oxygen atom attached thereto. In certain embodiments, an alkoxy has from 1 to 20 carbon atoms. In certain embodiments, an alkoxy has from 1 to 20 carbon atoms. Representative alkoxy groups include methoxy, trifluoromethoxy, ethoxy, propoxy, tert-butoxy, and the like. The term "alkoxyalkyl" refers to an alkyl group substituted with an alkoxy group and can be represented by the general formula alkyl-O-alkyl. The term "alkenyl" as used herein refers to an aliphatic group containing at least one double bond, and includes "unsubstituted alkenyl" and "substituted alkenyl", the latter of which refers to an alkenyl moiety having a substituent replacing a hydrogen atom on one or more carbon atoms of the alkenyl group. Typically, a linear or branched alkenyl group has 1 to about 20 carbon atoms, preferably 1 to about 10 carbon atoms, unless otherwise defined. Such a substituent may be present on one or more carbon atoms that are included or not included in one or more double bonds. Furthermore, such a substituent includes all of those considered as alkyl groups, as described below, so long as they do not impair stability. For example, substitution of an alkenyl group with one or more alkyl groups, carbocyclyl groups, aryl groups, heterocyclyl groups, or heteroaryl groups is considered. An "alkyl" group or "alkane" is a fully saturated, straight or branched chain non-aromatic hydrocarbon. Typically, a straight or branched chain alkyl group has from 1 to about 20 carbon atoms, preferably from 1 to about 12 carbon atoms, unless otherwise defined. In certain embodiments, an alkyl group has from 1 to 8 carbon atoms, 1 to 6 carbon atoms, 1 to 4 carbon atoms, or 1 to 3 carbon atoms. Examples of straight or branched chain alkyl groups include methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, pentyl, and octyl groups. Furthermore, the term "alkyl" as used throughout the specification, examples and claims is intended to include "unsubstituted alkyl" and "substituted alkyl", the latter of which refers to an alkyl moiety having a substituent replacing a hydrogen on one or more substitutable carbon atoms in the hydrocarbon backbone. Unless otherwise specified, such substituents may include, for example, a halogen group (e.g., a fluoro group), a hydroxyl group, a carbonyl group (e.g., a carboxyl, an alkoxycarbonyl, a formyl or an acyl group), a thiocarbonyl group (e.g., a thioester, a thioacetate or a thioformate group), an alkoxy group, a phosphoryl group, a phosphate group, a phosphonate group, a phosphinate group, an amino group, an amido group, an amidine group, an imine group, a cyano group, a nitro group, an azide group, a sulfhydryl group, an alkylthio group, a sulfate group, a sulfonate group, a sulfamoyl group, a sulfonamide group, a sulfonyl group, a heterocyclyl group, an aralkyl group, or an aromatic or heteroaromatic moiety. In a preferred embodiment, the substituent on the substituted alkyl group is selected from the group consisting of C 1-6 Alkyl group, C 3-6The substituents on the substituted alkyl group are selected from cycloalkyl groups, halogen groups, carbonyl groups, cyano groups, or hydroxy groups. In a more preferred embodiment, the substituents on the substituted alkyl group are selected from fluoro groups, carbonyl groups, cyano groups, or hydroxy groups. Those skilled in the art will appreciate that the substituted moieties on the hydrocarbon chain may themselves be substituted as required. For example, the substituents on the substituted alkyl group may include substituted and unsubstituted amino groups, azide groups, imino groups, amide groups, phosphoryl groups (including phosphonate groups and phosphinate groups), sulfonyl groups (including sulfate groups, sulfonamide groups, sulfamoyl groups, and sulfonate groups), and silyl groups, as well as ether groups, alkylthio groups, carbonyl groups (including ketone groups, aldehyde groups, carboxylate groups, and esters), -CF3, -CN, and the like. Exemplary substituted alkyl groups are described below. The cycloalkyl group may be further substituted with alkyl groups, alkenyl groups, alkoxy groups, alkylthio groups, aminoalkyl groups, alkyl groups substituted with carbonyl groups, -CF3, -CN, and the like. "C x-y The term "C" when used in connection with a chemical moiety (e.g., an acyl, acyloxy, alkyl, alkenyl, alkynyl, or alkoxy group) is meant to include groups containing x to y carbon atoms in the chain. For example, "C x-y The term "alkyl group" includes straight and branched chain alkyl groups that are substituted or unsubstituted saturated hydrocarbon groups containing x to y carbon atoms in the chain, and also includes haloalkyl groups. Preferred haloalkyl groups include trifluoromethyl, difluoromethyl, 2,2,2-trifluoroethyl and pentafluoroethyl groups. A C0 alkyl group refers to a hydrogen atom when the group is in a terminal position and a bond when the group is in an internal position. The term "C0 alkyl group" refers to a hydrogen atom when the group is in a terminal position and a bond when the group is in an internal position. 2-y Alkenyl group" and "C 2-y "Alkynyl" refers to substituted or unsubstituted unsaturated aliphatic groups analogous in length and possible substitution to the alkyl groups described above, but which contain at least one double or triple bond respectively. The term "alkylamino," as used herein, refers to an amino group substituted with at least one alkyl group. The term "alkylthio," as used herein, refers to a thiol group substituted with an alkyl group and may be represented by the general formula alkylS-. The term "arylthio," as used herein, refers to a thiol group substituted with an alkyl group and may be represented by the general formula arylS-. The term "alkynyl" as used herein refers to an aliphatic group containing at least one triple bond, and includes "unsubstituted alkynyl" and "substituted alkynyl", the latter of which refers to an alkynyl moiety having a substituent replacing hydrogen on one or more carbon atoms of the alkynyl group. Typically, unless otherwise defined, a straight or branched chain alkynyl group has 1 to about 20 carbon atoms, preferably 1 to about 10 carbon atoms. Such a substituent may be present on one or more carbon atoms that are included or not included in one or more triple bonds. Furthermore, such a substituent includes all of those considered as alkyl groups, as described below, so long as they do not impair stability. For example, substitution of an alkynyl group with one or more alkyl groups, carbocyclyl groups, aryl groups, heterocyclyl groups, or heteroaryl groups is considered. As used herein, the term "amide" refers to a group represented by the general formula: [ka] In the formula, R A each independently represents a hydrogen or a hydrocarbyl group, or two R A form, together with the N atom to which they are attached, a heterocycle having 4 to 8 atoms in the ring structure. The terms "amine" and "amino" are art-recognized and refer to unsubstituted and substituted amines and their salts, for example, groups represented by any of the general formulae: [ka] In the formula, R Aeach independently represents a hydrogen or a hydrocarbyl group, or two R A together with the N atom to which they are attached form a heterocycle having 4 to 8 atoms in the ring structure. The term "aminoalkyl," as used herein, refers to an alkyl group substituted with an amino group. The term "aralkyl," as used herein, refers to an alkyl group substituted with an aryl group. The term "aryl" as used herein includes substituted or unsubstituted monocyclic aromatic groups in which each atom of the ring is a carbon atom. Preferably, the ring is a 6- or 20-membered ring, more preferably a 6-membered ring. Preferably, the aryl has 6 to 10 carbon atoms, more preferably 6 to 25 carbon atoms. The term "aryl" also includes polycyclic ring systems having two or more cyclic rings in which two or more carbon atoms are shared between two adjacent rings, where at least one of the rings is aromatic and the other rings may be, for example, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl and / or heterocyclyl groups. Aryl groups include benzene, naphthalene, phenanthrene, phenol, aniline, and the like. The term "carbamate" is art recognized and refers to a group that may be represented by any of the general formulas: [ka] In the formula, R A each independently represents a hydrogen or a hydrocarbyl group (e.g., an alkyl group), or both R A forms, together with the intervening common atom, a heterocycle having 4 to 8 atoms in the ring structure. The terms "carbocycle" and "carbocyclic" as used herein refer to a saturated or unsaturated ring in which each atom of the ring is a carbon atom. Preferably, a carbocyclic group has 3 to 20 carbon atoms. The term "carbocycle" includes both aromatic and non-aromatic carbocycles. Non-aromatic carbocycles include cycloalkane rings in which all carbon atoms are saturated and cycloalkene rings that contain at least one double bond. Carbocycles include 5-7 membered monocyclic rings and 8-12 membered bicyclic rings. Each ring of a bicyclic carbocycle may be selected from saturated, unsaturated and aromatic rings. Carbocycles include bicyclic molecules in which one, two or three or more atoms are shared between the two rings. The term "fused carbocycle" refers to a bicyclic carbocycle in which each of the rings shares two adjacent atoms with the other ring. Each ring of a fused carbocycle may be selected from saturated, unsaturated and aromatic rings. In a typical embodiment, an aromatic ring (e.g., a phenyl (Ph) group) may be fused to a saturated or unsaturated ring (e.g., cyclohexane, cyclopentane, or cyclohexene). Any combination of saturated, unsaturated, and aromatic bicyclic rings is included in the definition of carbocycle, as long as valence permits. Typical "carbocycles" include cyclopentane, cyclohexane, bicyclo[2.2.1]heptane, 1,5-cyclooctadiene, 1,2,3,4-tetrahydronaphthalene, bicyclo[4.2.0]oct-3-ene, naphthalene, and adamantane. Examples of fused carbocycles include decalin, naphthalene, 1,2,3,4-tetrahydronaphthalene, bicyclo[4.2.0]octane, 4,5,6,7-tetrahydro-1H-indene, and bicyclo[4.1.0]hept-3-ene. A "carbocycle" may be substituted at any one or more positions that can hold a hydrogen atom. A "cycloalkyl" group is a fully saturated cyclic hydrocarbon. "Cycloalkyl" includes monocyclic and bicyclic rings. Preferably, a cycloalkyl group has 3 to 20 carbon atoms. Typically, a monocyclic cycloalkyl group has 3 to about 10 carbon atoms, and more typically, unless otherwise defined, has 3 to 8 carbon atoms. The second ring of a bicyclic cycloalkyl group may be selected from saturated, unsaturated, and aromatic rings. Cycloalkyl groups include bicyclic molecules in which one, two, or three or more atoms are shared between the two rings. The term "fused cycloalkyl" refers to a bicyclic cycloalkyl in which each of the rings shares two adjacent atoms with the other ring. The second ring of a fused bicyclic cycloalkyl may be selected from saturated, unsaturated, and aromatic rings. A "cycloalkenyl" group is a cyclic hydrocarbon containing one or more double bonds. The term "carbocyclylalkyl," as used herein, refers to an alkyl group substituted with a carbocycle group. As used herein, the term "carbonate" refers to -OCO-R A refers to the group, in which -R A represents a hydrocarbyl group. The term "carboxy," as used herein, refers to a group represented by the formula -CO2H. As used herein, the term "ester" refers to an ester of -C(O)OR A R A represents a hydrocarbyl group. The term "ether" as used herein refers to a group in which a hydrocarbyl group is linked to another hydrocarbyl group through an oxygen atom. Thus, an ether substituent of a hydrocarbyl group can be hydrocarbyl-O-. Ethers can be symmetrical or asymmetrical. Examples of ethers include, but are not limited to, heterocycle-O-heterocycle and aryl-O-heterocycle. Ethers include "alkoxyalkyl" groups, which can be represented by the general formula alkyl-O-alkyl. The terms "halo" and "halogen" as used herein refer to halogen atoms and include chlorine, fluorine, bromine and iodine. The terms "hetaralkyl" and "heteroaralkyl," as used herein, refer to an alkyl group substituted with a hetaryl group. The term "heteroalkyl," as used herein, refers to a saturated or unsaturated chain of carbon atoms and at least one heteroatom, where no two heteroatoms are adjacent. The terms "heteroaryl" and "hetaryl" include aromatic monocyclic structures, substituted or unsubstituted, preferably 5-20 membered, more preferably 5-6 membered, containing at least one heteroatom, preferably 1-4 heteroatoms, more preferably 1 or 2 heteroatoms in the ring structure. Preferably, the heteroaryl has 2-40 carbon atoms, more preferably 2-25 carbon atoms. The terms "heteroaryl" and "hetaryl" also include polycyclic ring systems having two or more cyclic rings in which two or more carbon atoms are shared by two adjacent rings, at least one of the rings being a heterocycle and the other rings may be, for example, a cycloalkyl group, a cycloalkenyl group, a cycloalkynyl group, an aryl group, a heteroaryl group, and / or a heterocyclyl group. Examples of heteroaryl groups include pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrazine, pyridazine, pyrimidine, and carbazole. The term "aryloxy" refers to an aryl group having an oxygen atom attached thereto. Preferably, the aryloxy has from 6 to 40 carbon atoms, more preferably from 6 to 25 carbon atoms. The term "heteroaryloxy" refers to an aryl group having an oxygen atom attached thereto. Preferably, the heteroaryloxy has from 3 to 40 carbon atoms, more preferably from 3 to 25 carbon atoms. The term "heteroatom" as used herein means an atom of any element other than a carbon or hydrogen atom. Preferred heteroatoms are nitrogen, oxygen and sulfur atoms. The terms "heterocyclyl", "heterocycle" and "heterocyclic" refer to a substituted or unsubstituted, preferably 3-20 membered, more preferably 3-7 membered, non-aromatic ring structure containing at least one heteroatom, preferably 1-4 heteroatoms, more preferably 1 or 2 heteroatoms. The terms "heterocyclyl" and "heterocyclic" also include polycyclic ring systems having two or more cyclic rings with two or more carbon atoms shared between two adjacent rings, where at least one of the rings is heterocyclic and the other rings may be, for example, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl and / or heterocyclyl groups. Heterocyclyl groups include, for example, piperidine, piperazine, pyrrolidine, morpholine, lactones, lactams, and the like. The term "heterocyclylalkyl," as used herein, refers to an alkyl group substituted with a heterocycle group. The term "hydrocarbyl" as used herein refers to a group that is bonded through a carbon atom and that carbon atom does not have a =O or =S substituent. Hydrocarbyl groups may optionally contain heteroatoms. Hydrocarbyl groups include, but are not limited to, alkyl, alkenyl, alkynyl, alkoxyalkyl, aminoalkyl, aralkyl, aryl, aralkyl, carbocyclyl, cycloalkyl, carbocyclylalkyl, heteroaralkyl, heteroaryl bonded through a carbon atom, heterocyclyl, heterocyclylalkyl, or hydroxyalkyl groups bonded through a carbon atom. That is, groups such as methyl, ethoxyethyl, 2-pyridyl, and trifluoromethyl are hydrocarbyl groups, but substituents such as acetyl (which has a =O substituent on the bonded carbon atom) and ethoxy (which is linked through an oxygen atom rather than a carbon atom) are not. The term "hydroxyalkyl," as used herein, refers to an alkyl group substituted with a hydroxy group. The term "lower" when used in connection with chemical moieties, such as, for example, acyl, acyloxy, alkyl, alkenyl, alkynyl, or alkoxy groups, refers to groups in which six or fewer non-hydrogen atoms are present in the substituent. A "lower alkyl" refers to, for example, an alkyl group containing six or fewer carbon atoms. In certain embodiments, an alkyl group has 1-6 carbon atoms, 1-4 carbon atoms, or 1-3 carbon atoms. In certain embodiments, the acyl, acyloxy, alkyl, alkenyl, alkynyl, or alkoxy groups that are substituents as defined herein, when present alone or in combination with other substituents (e.g., hydroxyalkyl and aralkyl groups) (e.g., atoms in aryl groups are not counted when counting the number of carbon atoms in an alkyl group), are, respectively, lower acyl, lower acyloxy, lower alkyl, lower alkenyl, lower alkynyl, or lower alkoxy groups. The terms "polycyclyl", "polycyclic" and "polycyclic" refer to two or more rings, such as, for example, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl and / or heterocyclyl groups, in which two or more carbon atoms are shared between two adjacent rings, such as "fused rings". Each ring in a polycycle may be substituted or unsubstituted. In certain embodiments, each ring in a polycycle contains 3-10, preferably 5-7, atoms in the ring. In the term "poly(metaphenylene oxide)," the term "phenylene" refers generally to a 6-membered aryl or 6-membered heteroaryl moiety. Exemplary poly(metaphenylene oxide)s are described as the first to twentieth embodiments of the present disclosure. The term "silyl" refers to a silicon moiety having three hydrocarbyl moieties attached thereto. The term "substituted" refers to a moiety having a substituent replacing a hydrogen on one or more carbon atoms in the backbone. Of course, when referring to "substituted" or "substituted with", it is implied that such substitution is in accordance with the valence of the substituted atom and the substituent, and that the substitution stabilizes the compound (e.g., does not spontaneously cause a change such as rearrangement, cyclization, elimination, etc.). Moieties that may be substituted include any suitable substituent as described herein, such as acyl, acylamino, acyloxy, alkoxy, alkoxyalkyl, alkenyl, alkyl, alkylamino, alkylthio, arylthio, alkynyl, amido, amino, aminoalkyl, aralkyl, carbamate, carbocyclyl, cycloalkyl, carbocyclylalkyl, carbonate, ester, ether, heteroaralkyl, heterocyclyl, heterocyclylalkyl, hydrocarbyl, silyl, sulfone, or thioether. As used herein, the term "substituted" is intended to include all substituents that may be present in an organic compound. In a broad sense, the substituents that may be present include acyclic and cyclic, branched and unbranched, carbocyclic and heterocyclic, aromatic and non-aromatic substituents of organic compounds. The substituents that may be present may be one or more, the same or different, for suitable organic compounds. For purposes of the present invention, heteroatoms such as nitrogen may have hydrogen substituents and / or any substituents that may be present in organic compounds that satisfy the valence of the heteroatom as described herein. Substituents include any of the substituents described herein, such as halogens, hydroxyl groups, carbonyl groups (e.g., carboxyl, alkoxycarbonyl, formyl, or acyl groups), thiocarbonyl groups (e.g., thioester, thioacetate, or thioformate groups), alkoxy groups, phosphoryl groups, phosphate groups, phosphonate groups, phosphinate groups, amino groups, amido groups, amidine groups, imine groups, cyano groups, nitro groups, azido groups, sulfhydryl groups, alkylthio groups, sulfate groups, sulfonate groups, sulfamoyl groups, sulfonamide groups, sulfonyl groups, heterocyclyl groups, aralkyl groups, or aromatic or heteroaromatic moieties.In a preferred embodiment, the substituents of the substituted alkyl group are C. 1-6 Alkyl group, C 3-6 The substituents of the substituted alkyl groups are selected from cycloalkyl groups, halogen groups, carbonyl groups, cyano groups, and hydroxy groups. In a more preferred embodiment, the substituents of the substituted alkyl groups are selected from fluoro groups, carbonyl groups, cyano groups, and hydroxy groups. Those skilled in the art will appreciate that the substituents may themselves be substituted as appropriate. Unless specifically described as "unsubstituted," references to chemical moieties herein are understood to include substituted modifications. For example, references to "aryl" groups or moieties implicitly include substituted and unsubstituted modifications. The term "sulfonate" is art recognized and refers to the group SO3H or a pharma- ceutically acceptable salt thereof. The term "sulfone" is art recognized and refers to the -S(O)-R A R A represents a hydrocarbyl group. The term "thioether" as used herein is an ether equivalent where the oxygen has been replaced with a sulfur. The term "symmetric molecule" as used herein refers to a molecule that is group symmetric or synthetically symmetric. The term "group symmetric" as used herein refers to a molecule that is symmetric according to the molecular symmetry theory with respect to a group. The term "synthetically symmetric" as used herein refers to a molecule that is selected such that no regioselective synthetic route is required. The term "donor" as used herein refers to a molecular fragment that can be used in an organic light emitting diode and that, upon excitation, has the property of donating an electron from its highest occupied molecular orbital to an acceptor. In an exemplary embodiment, the donor has an ionization potential of -6.5 eV or greater. As used herein, the term "acceptor" refers to a molecular fragment that can be used in an organic light emitting diode and that has the property of accepting an electron from an excited donor into its lowest unoccupied molecular orbital. In an exemplary embodiment, the acceptor has an electron affinity of -0.5 eV or less. The term "bridge" as used herein refers to a molecular fragment that may be included in a molecule that covalently bonds between an acceptor and a donor moiety. The bridge may be further conjugated, for example, to the acceptor moiety, the donor moiety, or both. Without being bound to a particular theory, it is believed that the bridging moiety may sterically restrict the acceptor and donor moieties to a specific configuration, thereby preventing the formation of a pi-conjugated portion of the donor and acceptor moieties. Examples of suitable bridging moieties include phenyl, ethenyl, and ethynyl moieties. As used herein, the term "multivalent" refers to a molecular fragment that binds to at least two other molecular fragments. For example, a bridging moiety is multivalent. As used herein, "~~~" or "*" refers to a bond site between two atoms. "Hole transport layer (HTL)" and similar terms refer to a layer made of a material that transports holes. It is recommended that it has high hole transporting ability. The HTL is used to block the passage of electrons transported by the emissive layer. A low electron affinity is typically required to block electrons. The HTL should preferably have a high triplet to block exciton transfer from the adjacent emissive layer (EML). Examples of HTL compounds include, but are not limited to, di(p-tolyl)aminophenyl]cyclohexane (TPAC), N,N-diphenyl-N,N-bis(3-methylphenyl)-1,1-biphenyl-4,4-diamine (TPD), and N,N'-diphenyl-N,N'-bis(1-naphthyl)-(1,1'-biphenyl)-4,4'-diamine (NPB, α-NPD). "Emitting layer" and similar terms refer to a layer that emits light. In some embodiments, the emitting layer is composed of a host material and a guest material. The guest material is also called a dopant material, but the present disclosure is not so limited. The host material may be bipolar or unipolar and may be used alone or in combination with two or more host materials. The opto-electrical properties of the host material may vary depending on which type of guest material (TADF, phosphorescent, or fluorescent) is used. For fluorescent guest materials, the host material should have good spectral overlap between the absorption of the guest material and the emission of the host material to induce good Forster transfer to the guest material. For phosphorescent guest materials, the host material should have high triplet energy to confine the triplet of the guest material. For TADF guest materials, the host material should have both spectral overlap and high triplet energy. "Dopant" and similar terms refer to additives for carrier transport layers, light-emitting layers or other layers. In carrier transport layers, dopants and similar terms refer to electron acceptors or donors that, when added to an organic layer as an additive, increase the conductivity of the organic layer of an organic electronic device. By doping, organic semiconductors can be similarly influenced with respect to their electrical conductivity. Such organic semiconductor matrix materials can be made from compounds with electron-donating properties or compounds with electron-accepting properties. In light-emitting layers, dopants and similar terms refer to light-emitting materials dispersed in a matrix, such as a host. When a triplet harvesting material is doped into the light-emitting layer or included in an adjacent layer to increase the exciton generation efficiency, it is called an assist dopant. The assist dopant can rather shorten the exciton lifetime. The content of the assist dopant in the light-emitting layer or adjacent layer is not particularly limited, as long as the triplet harvesting material increases the exciton generation rate. The content of the assist dopant in the light-emitting layer is preferably greater than the light-emitting material, and more preferably at least twice as much as the light-emitting material. In the light-emitting layer, the content of the host material is preferably 50% by weight or more, the content of the assist dopant is preferably 5% by weight to less than 50% by weight, and the content of the light-emitting material is preferably 0% by weight to 30% by weight, more preferably 0% by weight to less than 10% by weight. The content of the assist dopant in the adjacent layer may be 50% by weight or more, and may be 100% by weight. When a device containing a triplet harvesting material in the light-emitting layer or an adjacent layer has a higher luminous efficiency than a device without the triplet harvesting material, such a triplet harvesting material functions as an assist dopant. The light-emitting layer containing the host material, the assist dopant, and the light-emitting material satisfies the following (A), and preferably satisfies the following (B). ES1(A)>ES1(B)>ES1(C) (A) ET1(A)>ET1(B) (B) Here, ES1(A) indicates the lowest excited singlet energy level of the host material, ES1(B) indicates the lowest excited singlet energy level of the assist dopant, ES1(C) indicates the lowest excited singlet energy level of the light-emitting material, ET1(A) indicates the lowest excited triplet energy level of the host material at 77 K, and ET1(B) indicates the lowest excited triplet energy level of the assist dopant at 77 K. The assist dopant has an energy difference ΔE between the lowest singlet excited state and the lowest triplet excited state at 77 K of preferably 0.3 eV or less, more preferably 0.2 eV or less, and even more preferably 0.1 eV or less. ST has. In the compounds of the present invention, any atom not specified as a specific isotope is encompassed as any stable isotope of that atom. Unless otherwise specified, when a state is specified as "H" or "hydrogen", the state is understood to have hydrogen in its natural isotopic composition. Also, unless otherwise specified, when a state is specified as "D" or "deuterium", the state is understood to have an amount of deuterium at least 3340 times higher than the natural amount of deuterium, 0.015% (i.e., a deuterium content of at least 50.1%). As used herein, the term "isotope enrichment" refers to the ratio of the amount of an isotope to the amount of a particular isotope found in nature. In various embodiments, the compounds of the invention have an isotopic enrichment (for each deuterium atom content) of at least 3500 (52.5% deuterium content for each deuterium atom content), at least 4000 (60% deuterium content), at least 4500 (67.5% deuterium content), at least 5000 (75% deuterium content), at least 5500 (82.5% deuterium content), at least 6000 (90% deuterium content), at least 6333.3 (95% deuterium content), at least 6466.7 (97% deuterium content), at least 6600 (99% deuterium content), or at least 6633.3 (99.5% deuterium content). The term "isotopically modified" refers to species that differ from specific compounds of the invention only in isotopic composition. When referring to the compounds of the present invention, the term "compound" refers to a collection of molecules having the same chemical structure, although there may be isotopic variations between the constituent atoms of the molecule. Thus, as will be appreciated by those skilled in the art, a compound represented by a particular chemical structure containing a given deuterium atom may also contain some isotopic substitutions having hydrogen atoms at one or more of the positions of the given deuterium in the structure. The relative amount of such isotopic substitutions in the compounds of the present invention depends on many factors, such as the isotopic purity of the deuteration reagent used to prepare the compound, and the efficiency of deuterium incorporation in the various synthetic steps to prepare the compound. However, as mentioned above, the relative amount of such isotopic substitutions is less than 49.9% of the compound overall. In other embodiments, the relative amount of such isotopic substitutions is less than 47.5%, less than 40%, less than 32.5%, less than 25%, less than 17.5%, less than 10%, less than 5%, less than 3%, less than 1% or less than 0.5% of the compound overall. "Deuterium substituted" refers to one or more hydrogen atoms being replaced with the corresponding number of deuterium atoms. "D" and "d" refer to deuterium.

[0035] (The principle of OLED) OLEDs typically consist of a layer of organic materials or compounds between two electrodes (anode and cathode). Organic molecules are electrically conductive as a result of delocalization of π electrons due to bonding with some or all of the molecule. When a voltage is applied, an electron from the highest occupied molecular orbital (HOMO), present at the anode, flows into the lowest unoccupied molecular orbital (LUMO) of the organic molecule, present at the cathode. Removal of an electron from the HOMO is also referred to as injecting an electron hole into the HOMO. Electrostatic forces force the electron and hole towards each other, causing them to recombine and form an exciton (a combined state of electron and hole). When the excited state is deactivated and the energy levels of the electrons relax, radiation with frequencies in the visible spectrum is emitted. The frequency of this radiation depends on the band gap of the material, i.e., the energy difference between the HOMO and the LUMO. When electrons and holes are fermions with half-integer spin, excitons can be in singlet or triplet states depending on how the electron and hole spins are coupled. Statistically, three triplet excitons are formed for every singlet exciton. Decay from the triplet state is spin-forbidden, which leads to an increase in the time scale of the transition and limits the internal efficiency of fluorescent devices. Phosphorescent organic light-emitting diodes exploit spin-orbit interactions to facilitate intersystem crossing across singlet and triplet states, thereby producing emission from singlet and triplet states and improving internal efficiency. One prototypical phosphorescent material is iridium tris(2-phenylpyridine) (Ir(ppy)3), in which charge transfer from an Ir atom to an organic ligand results in an excited state. Such an approach has reduced triplet lifetimes to around a few microseconds, orders of magnitude slower than the radiative lifetimes of fully allowed transitions such as fluorescence. Although Ir-based phosphors have proven acceptable for many display applications, losses due to high triplet densities have prevented their application in OLEDs as high-brightness solid-state lighting devices. Thermally activated delayed fluorescence (TADF) is a method to measure the energy difference between the singlet and triplet states (ΔE ST ) The reduction of the exchange splitting from typical values ​​of 0.4-0.7 eV to a gap on the order of thermal energy (proportional to kBT, kB representing the Boltzmann constant and T the temperature) means that thermal stirring can transition the population between the singlet and triplet levels on reasonable timescales, even if the coupling between the states is small. TADF molecules consist of donor and acceptor moieties that are linked by a covalent bond directly or through a conjugated linker (or "bridge"). The "donor" moiety has the property of transferring an electron from its HOMO to the "acceptor" moiety upon excitation. The "acceptor" moiety has the property of accepting an electron from the "donor" moiety to its LUMO. The donor-acceptor nature of TADF molecules allows for very low ΔE STSince thermal molecular motion can randomly alter the optical properties of the donor-acceptor system, the rigid steric configuration of the donor and acceptor moieties can be exploited to limit nonradiative deactivation of the charge-transfer state by internal conversion during the excited state lifetime. Therefore, ΔE ST It would be advantageous to develop systems with high reverse intersystem crossing (RISC) that can utilize triplet excitons and reduce the charge transport. Such systems would result in increased quantum efficiency and reduced emission lifetime. Systems with these characteristics would be able to emit light without the rapid decomposition typically seen in OLEDs known today.

[0036] In certain embodiments of the present disclosure, the luminescent materials of the present invention, when excited by thermal or electronic means, can emit light in the UV region, the blue, green, yellow, orange, red region of the visible spectrum (e.g., from about 420 nm to about 500 nm, from about 500 nm to about 600 nm, or from about 600 nm to about 700 nm), or the near infrared region. In certain embodiments of the present disclosure, the luminescent materials of the present invention can emit light in the red or orange region of the visible spectrum (e.g., from about 620 nm to about 780 nm, about 650 nm) when excited by thermal or electronic means. In certain embodiments of the present disclosure, the luminescent materials of the present invention, when excited by thermal or electronic means, can emit light in the orange or yellow region of the visible spectrum (e.g., from about 570 nm to about 620 nm, about 590 nm, about 570 nm). In certain embodiments of the present disclosure, the luminescent materials of the present invention can emit light in the green region of the visible spectrum (e.g., from about 490 nm to about 575 nm, about 510 nm) when excited by thermal or electronic means. In certain embodiments of the present disclosure, the luminescent materials of the present invention can emit light in the blue region of the visible spectrum (e.g., from about 400 nm to about 490 nm, about 475 nm) when excited by thermal or electronic means. In certain embodiments of the present disclosure, the luminescent materials of the present invention are capable of emitting light in the ultraviolet spectral region (eg, 280-400 nm) when excited by thermal or electronic means. In certain embodiments of the present disclosure, the luminescent materials of the present invention are capable of emitting light in the infrared spectral region (eg, 780 nm to 2 μm) when excited by thermal or electronic means.

[0037] (Compound Selection) The electronic properties of small molecule chemical libraries can be calculated using known ab initio quantum chemical calculations. For example, the Hartree-Fock equations (TD-DFT / B3LYP / 6-31G*) can be analyzed using time-dependent density functional theory with 6-31G* and the family of functions known as Becke's three-parameter Lee-Yang-Parr hybrid functionals as the basis, to screen for molecular fragments (moieties) that have a HOMO above a certain threshold and a LUMO below a certain threshold, and the calculated triplet state of the moiety is greater than 2.75 eV. Thus, a donor moiety ("D") can be selected, for example, with a HOMO energy (e.g., ionization potential) of -6.5 eV or greater, and an acceptor moiety ("A") can be selected, for example, with a LUMO energy (e.g., electron affinity) of -0.5 eV or less. The bridging moiety ("B") prevents overlap between the pi-conjugated systems of the donor and acceptor moieties, for example, by providing a strongly conjugated system that can tightly restrict the acceptor and donor moieties into specific conformations. In one embodiment, the compound library is screened using one or more of the following properties: 1. Emission around a specific wavelength 2. Calculated triplet states above a specific energy level 3. ΔE below a certain value ST value 4. Quantum yield above a certain value 5.HOMO level 6.LUMO Level In one embodiment, the difference between the lowest singlet excited state and the lowest triplet excited state at 77 K (ΔE ST ) is less than about 0.5 eV, less than about 0.4 eV, less than about 0.3 eV, less than about 0.2 eV, or less than about 0.1 eV. In some embodiments, ΔE ST The value is less than about 0.09 eV, less than about 0.08 eV, less than about 0.07 eV, less than about 0.06 eV, less than about 0.05 eV, less than about 0.04 eV, less than about 0.03 eV, less than about 0.02 eV, or less than about 0.01 eV. In certain embodiments, the emissive materials of the present invention exhibit a quantum yield of greater than 25%, e.g., about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or more.

[0038] (Film formation) In an embodiment, the film containing the light-emitting material of the present invention can be formed by a wet process. In the wet process, a solution in which the light-emitting material of the present invention is dissolved is applied to a surface, and a film is formed after removing the solvent. Examples of the wet process include, but are not limited to, spin coating, slit coating, inkjet (spray) printing, gravure printing, offset printing, and flexographic printing. In the wet process, an appropriate organic solvent capable of dissolving the light-emitting material of the present invention is selected and used. For example, a non-polar solvent such as an aromatic hydrocarbon solvent containing toluene can be used, but the usable solvents are not limited to these. In an embodiment, a substituent (e.g., an alkyl group) that increases the solubility in organic solvents can be introduced into the compound contained in the light-emitting material. In an embodiment, the film containing the light-emitting material of the present invention can be formed by a dry process. In an embodiment, the dry process can be a vacuum deposition method, but is not limited thereto. When the vacuum deposition method is adopted, the compounds constituting the film may be co-deposited from individual deposition sources, or may be co-deposited from a single deposition source in which the compounds are mixed. When a single deposition source is used, a mixed powder in which powders of the compounds are mixed may be used, or a compression molded body in which the mixed powder is compressed may be used, or a mixture in which each compound is heated, melted, and cooled may be used. In an embodiment, a film having a composition ratio corresponding to the composition ratio of the multiple compounds contained in the deposition source can be formed by performing co-deposition under conditions in which the deposition rates (weight reduction rates) of the multiple compounds contained in a single deposition source are the same or almost the same. If a multiple compound is mixed in the same composition ratio as the composition ratio of the film to be formed and used as a deposition source, a film having a desired composition ratio can be easily formed. In an embodiment, a temperature at which each compound to be co-deposited has the same weight reduction rate is specified, and the temperature can be used as the temperature during co-deposition.

[0039] [Examples of Use of the Luminescent Material of the Present Disclosure] (Organic Light Emitting Diode) One aspect of the present invention relates to the use of the luminescent material of the present invention as a light-emitting material in an organic light-emitting device. In an embodiment, the luminescent material of the present invention can be effectively used as a light-emitting material in the light-emitting layer of an organic light-emitting device. In an embodiment, the luminescent material of the present invention comprises a delayed fluorescence (delayed fluorescent material) that emits delayed fluorescence. In an embodiment, the present invention provides a delayed fluorescent material comprising the luminescent material of the present invention. In an embodiment, the present invention relates to the use of the luminescent material of the present invention as a delayed fluorescent material. In an embodiment, the present invention relates to a method for generating delayed fluorescence from the luminescent material of the present invention. In an embodiment, an organic light-emitting device comprising the luminescent material of the present invention as a light-emitting material emits delayed fluorescence and exhibits high light emission efficiency. In some embodiments, including the luminescent material of the present invention, the donor compound, the acceptor compound and the luminescent compound are aligned parallel to the substrate. In some embodiments, the substrate is a film-forming surface. In some embodiments, the orientation of the donor compound, the acceptor compound and the luminescent compound relative to the film-forming surface affects or dictates the propagation direction of light emitted by the aligned compounds. In some embodiments, aligning the propagation direction of light emitted by the donor compound, the acceptor compound and the luminescent compound improves the light extraction efficiency from the luminescent layer. One aspect of the present invention relates to an organic light-emitting device. In an embodiment, the organic light-emitting device includes an emitting layer. In an embodiment, the emitting layer includes the emitting material of the present invention as the emitting material. In an embodiment, the organic light-emitting device is an organic photoluminescence device (organic PL device). In an embodiment, the organic light-emitting device is an organic electroluminescence device (organic EL device). In an embodiment, the exciplex formed by the donor compound and the acceptor compound assists the light emission of other emitting materials contained in the emitting layer (as a so-called assist dopant). In an embodiment, the exciplex formed by the donor compound and the acceptor compound contained in the emitting layer is at its lowest excited singlet energy level, and is included between the lowest excited singlet energy level of the host material contained in the emitting layer and the lowest excited singlet energy level of the other emitting materials contained in the emitting layer. In some embodiments, the organic photoluminescent device includes at least one light-emitting layer. In some embodiments, the organic electroluminescent device includes at least an anode, a cathode, and an organic layer between the anode and the cathode. In some embodiments, the organic layer includes at least an emitting layer. In some embodiments, the organic layer includes only an emitting layer. In some embodiments, the organic layer includes one or more organic layers in addition to the emitting layer. Examples of 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, and an exciton blocking layer. In some embodiments, the hole transport layer may be a hole injection transport layer with hole injection function, and the electron transport layer may be an electron injection transport layer with electron injection function. An example of an organic electroluminescent device is shown in FIG. 1.

[0040] (base material) In one embodiment, the organic electroluminescent device of the present invention is supported by a substrate, which is not particularly limited and may be any material commonly used in organic electroluminescent devices, such as glass, transparent plastic, quartz, and silicon.

[0041] (anode) In some embodiments, the anode of the organic electroluminescent device is made of a metal, an alloy, a conductive compound, or a combination thereof. In some embodiments, the metal, alloy, or conductive compound has a high work function (4 eV or more). In some embodiments, the metal is Au. In some embodiments, the conductive transparent material is selected from CuI, indium tin oxide (ITO), SnO2, and ZnO. In some embodiments, an amorphous material capable of forming a transparent conductive film, such as IDIXO (In2O3-ZnO), is used. In some embodiments, the anode is a thin film. In some embodiments, the thin film is made by deposition or sputtering. In some embodiments, the film is patterned by a photolithographic method. In some embodiments, if the pattern does not need to be highly accurate (e.g., about 100 μm or more), the pattern may be formed using a mask with a shape suitable for deposition or sputtering on the electrode material. In some embodiments, when a coating material such as an organic conductive compound can be applied, a wet film formation method such as a printing method or a coating method is used. In some embodiments, the anode has a transmittance of more than 10% when emitted light passes through the anode, and the anode has a sheet resistance of several hundred ohms or less per unit area. In some embodiments, the anode has a thickness of 10 to 1,000 nm. In some embodiments, the anode has a thickness of 10 to 200 nm. In some embodiments, the thickness of the anode varies depending on the material used.

[0042] (cathode) In some embodiments, the cathode is made of an electrode material such as a metal with a low work function (4 eV or less) (referred to as an electron-injecting metal), an alloy, a conductive compound, or a combination thereof. In some embodiments, the electrode material is selected from 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, and rare earth elements. In some embodiments, a mixture of an electron-injecting metal and a second metal, which is a stable metal with a higher work function than the electron-injecting metal, is used. In some embodiments, the mixture is selected from magnesium-silver mixture, magnesium-aluminum mixture, magnesium-indium mixture, aluminum-aluminum oxide (Al2O3) mixture, lithium-aluminum mixture, and aluminum. In some embodiments, the mixture improves the electron-injecting properties and resistance to oxidation. In some embodiments, the cathode is fabricated by forming the electrode material as a thin film by evaporation or sputtering. In some embodiments, the cathode has a sheet resistance of several hundred ohms or less per unit area. In some embodiments, the cathode has a thickness of 10 nm to 5 μm. In some embodiments, the cathode has a thickness of 50 to 200 nm. In some embodiments, one of the anode and cathode of the organic electroluminescent device is transparent or semi-transparent to transmit emitted light. In some embodiments, a transparent or semi-transparent electroluminescent device improves light radiance. In some embodiments, the cathode is formed from a conductive, transparent material as described above for the anode, thereby forming a transparent or semi-transparent cathode. In some embodiments, the device includes an anode and a cathode, both of which are transparent or semi-transparent.

[0043] (Light Emitting Layer) In some embodiments, the light-emitting layer is a layer in which holes and electrons injected from the anode and cathode, respectively, recombine to form excitons, hi some embodiments, the layer emits light. In some embodiments, only the light-emitting material is used as the light-emitting layer. In some embodiments, the light-emitting layer includes a light-emitting material and a host material. In some embodiments, the light-emitting material is an exciplex formed by a donor compound and an acceptor compound or a light-emitting compound. In some embodiments, the singlet and triplet excitons generated in the light-emitting material are trapped in the light-emitting material to improve the light emission efficiency of the organic electroluminescent device and the organic photoluminescent device. In some embodiments, a host material is used in addition to the light-emitting material in the light-emitting layer. In some embodiments, the host material is an organic compound. In some embodiments, the organic compound has an excited singlet energy and an excited triplet energy, at least one of which is higher than those of the light-emitting material of the present invention. In some embodiments, the singlet and triplet excitons generated in the light-emitting material of the present invention are trapped in the molecules of the light-emitting material of the present invention. In some embodiments, the singlet and triplet excitons are sufficiently trapped to improve the light emission efficiency. In some embodiments, host materials that do not adequately confine singlet and triplet excitons, i.e., achieve high light emission efficiency, while still achieving high light emission efficiency, may be used in the present invention without any particular limitations. In some embodiments, light emission occurs in the light-emitting material in the light-emitting layer of the device of the present invention. In some embodiments, the emitted light includes both fluorescence and delayed fluorescence. In some embodiments, the emitted light includes light emitted from the host material. In some embodiments, the emitted light consists of light emitted from the host material. In some embodiments, the emitted light includes light emitted from the exciplex formed by the donor compound and the acceptor compound and light emitted from the light-emitting compound and light emitted from the host material. In some embodiments, TADF molecules and a host material are used. In some embodiments, TADF is an assist dopant. In some embodiments, when a host material is used, the amount of exciplexes and emissive compounds in the emissive layer is 0.1% by weight or more. In some embodiments, when a host material is used, the amount of exciplexes and emissive compounds in the emissive layer is 1% by weight or more. In some embodiments, when a host material is used, the amount of exciplexes and emissive compounds in the emissive layer is 50% by weight or less. In some embodiments, when a host material is used, the amount of exciplexes and emissive compounds in the emissive layer is 20% by weight or less. In some embodiments, when a host material is used, the amount of exciplexes and emissive compounds in the emissive layer is 10% by weight or less. In some embodiments, the host material of the light-emitting layer is an organic compound that has hole transport and electron transport functions. In some embodiments, the host material of the light-emitting layer is an organic compound that prevents the wavelength of emitted light from increasing. In some embodiments, the host material of the light-emitting layer is an organic compound that has a high glass transition temperature. In one embodiment, the light-emitting layer contains two or more types of TADF molecules with different structures. For example, the light-emitting layer may contain three materials, the host material, the first TADF molecule, and the second TADF molecule, whose excited singlet energy levels are higher in this order. In this case, the first TADF molecule and the second TADF molecule both have a difference ΔE between the lowest excited singlet energy level and the lowest excited triplet energy level of 77K. STis preferably 0.3 eV or less, more preferably 0.25 eV or less, more preferably 0.2 eV or less, more preferably 0.15 eV or less, even more preferably 0.1 eV or less, even more preferably 0.07 eV or less, even more preferably 0.05 eV or less, even more preferably 0.03 eV or less, and particularly preferably 0.01 eV or less. The content of the first TADF molecule in the light-emitting layer is preferably greater than the content of the second TADF molecule. The content of the host material in the light-emitting layer is preferably greater than the content of the second TADF molecule. The content of the first TADF molecule in the light-emitting layer may be greater than, less than, or the same as the content of the host material. In an embodiment, the composition in the light-emitting layer may be 10 to 70 wt % of the host material, 10 to 80 wt % of the first TADF molecule, and 0.1 to 30 wt % of the second TADF molecule. In an embodiment, the composition in the light-emitting layer may be 20 to 45% by weight of the host material, 50 to 75% by weight of the first TADF molecule, and 5 to 20% by weight of the second TADF molecule. In an embodiment, the light emission quantum yield φPL1(A) by light excitation of the co-deposited film of the first TADF molecule and the host material (content of the first TADF molecule in this co-deposited film = A weight %) and the light emission quantum yield φPL2(A) by light excitation of the co-deposited film of the second TADF molecule and the host material (content of the second TADF molecule in this co-deposited film = A weight %) satisfy the relational expression φPL1(A) > φPL2(A). In an embodiment, the light emission quantum yield φPL2(B) by light excitation of the co-deposited film of the second TADF molecule and the host material (content of the second TADF molecule in this co-deposited film = B weight %) and the light emission quantum yield φPL2(100) by light excitation of the single film of the second TADF molecule satisfy the relational expression φPL2(B) > φPL2(100). In some embodiments, the light-emitting layer may contain three structurally different TADF molecules. The exciplex and light-emitting compound of the present invention may be any of the multiple TADF compounds contained in the light-emitting layer. In some embodiments, the light-emitting layer can be made of a material selected from the group consisting of a host material, an assist dopant, and a light-emitting material. In some embodiments, the light-emitting layer does not contain a metal element. In some embodiments, the light-emitting layer can be made of a material consisting of only atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, and sulfur atoms. Alternatively, the light-emitting layer can be made of a material consisting of only atoms selected from the group consisting of carbon atoms, hydrogen atoms, and nitrogen atoms. When the light-emitting layer contains a TADF material, the TADF material may be a known delayed fluorescent material. Preferred delayed fluorescent materials include those described in paragraphs 0008-0048 and 0095-0133 of WO2013 / 154064, paragraphs 0007-0047 and 0073-0085 of WO2013 / 011954, paragraphs 0007-0033 and 0059-0066 of WO2013 / 011955, and paragraph 0008 of WO2013 / 081088. JP 2013-256490 A, paragraphs 0009 to 0046 and 0093 to 0134; JP 2013-116975 A, paragraphs 0008 to 0020 and 0038 to 0040; WO 2013 / 133359 A, paragraphs 0007 to 0032 and 0079 to 0084; WO 2013 / 161437 A, paragraph 0 JP 2014-9352 A, paragraphs 0007-0041 and 0060-0069, JP 2014-9224 A, paragraphs 0008-0048 and 0067-0076, JP 2017-119663 A, paragraphs 0013-0025, JP 2017-119664 A, paragraphs 0013-0026, JP 2017-119664 A, The compounds included in the general formulas described in paragraphs 0012 to 0025 of JP 017-222623 A, paragraphs 0010 to 0050 of JP 2017-226838 A, paragraphs 0012 to 0043 of JP 2018-100411 A, and paragraphs 0016 to 0044 of WO 2018 / 047853 A, particularly the example compounds, which are capable of emitting delayed fluorescence, are included.In addition, the following publications are included herein: JP2013-253121A, WO2013 / 133359A, WO2014 / 034535A, WO2014 / 115743A, WO2014 / 122895A, WO2014 / 126200A, WO2014 / 136758A, WO2014 / 133121A, WO20 14 / 136860, WO2014 / 196585, WO2014 / 189122, WO2014 / 168101, WO2015 / 008 580 publication, WO2014 / 203840 publication, WO2015 / 002213 publication, WO2015 / 016200 publication, WO2015 / 019725 publication, WO2015 / 072470, WO2015 / 108049, WO2015 / 080182, WO2015 / 072537, WO2015 / 080183, JP2015-129240A, WO2015 / 129714A, WO2015 / 129715A, WO2015 / 13350 The luminescent materials described in WO2015 / 136880, WO2015 / 137244, WO2015 / 137202, WO2015 / 137136, WO2015 / 146541, and WO2015 / 159541, which are capable of emitting delayed fluorescence, can be preferably used. Note that the above publications described in this paragraph are hereby incorporated by reference as part of this specification.

[0044] (Injection layer) An injection layer is a layer between an electrode and an organic layer. In some embodiments, the injection layer reduces driving voltage and enhances light radiance. In some embodiments, the injection layer comprises a hole injection layer and an electron injection layer. The injection layer can be disposed 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. In some embodiments, an injection layer is present. In some embodiments, an injection layer is not present. Preferred examples of compounds that can be used as the hole injection material are given below.

[0045] [ka]

[0046] Next, preferred examples of compounds that can be used as the electron injection material will be given. [ka]

[0047] (Barrier layer) A barrier layer is a layer that can prevent charges (electrons or holes) and / or excitons present in the light-emitting layer from diffusing outside the light-emitting layer. In some embodiments, an electron barrier layer is present between the light-emitting layer and the hole transport layer and prevents electrons from passing through the light-emitting layer to the hole transport layer. In some embodiments, a hole barrier layer is present between the light-emitting layer and the electron transport layer and prevents holes from passing through the light-emitting layer to the electron transport layer. In some embodiments, a barrier layer prevents excitons from diffusing outside the light-emitting layer. In some embodiments, the electron barrier layer and the hole barrier layer constitute an exciton barrier layer. As used herein, the term "electron barrier layer" or "exciton barrier layer" includes layers that have both the functions of an electron barrier layer and of an exciton barrier layer.

[0048] (Hole blocking layer) The hole blocking layer functions as an electron transport layer. In some embodiments, during electron transport, the hole blocking layer prevents holes from reaching the electron transport layer. In some embodiments, the hole blocking layer increases the probability of recombination of electrons and holes in the light-emitting layer. The materials used for the hole blocking layer can be the same materials as those described above for the electron transport layer. Preferred examples of compounds that can be used in the hole blocking layer are given below.

[0049] [ka]

[0050] [ka]

[0051] (Electron barrier layer) The electron blocking layer transports holes. In some embodiments, during hole transport, the electron blocking layer blocks electrons from reaching the hole transport layer. In some embodiments, the electron blocking layer increases the probability of recombination of electrons and holes in the light-emitting layer. The materials used for the electron blocking layer can be the same materials as those described above for the hole transport layer. Specific examples of preferred compounds that can be used as the electron blocking material are given below.

[0052] [ka]

[0053] (Exciton blocking layer) The exciton blocking layer prevents excitons generated through the recombination of holes and electrons in the light-emitting layer from diffusing to the charge transport layer. In some embodiments, the exciton blocking layer allows for effective confinement of excitons in the light-emitting layer. In some embodiments, the light emission efficiency of the device is improved. In some embodiments, the exciton blocking layer is adjacent to the light-emitting layer on either the anode side or the cathode side and on both sides. In some embodiments, when the exciton blocking layer is present on the anode side, the layer may be present between the hole transport layer and the light-emitting layer and adjacent to the light-emitting layer. In some embodiments, when the exciton blocking layer is present on the cathode side, the layer may be present between the light-emitting layer and the cathode and adjacent to the light-emitting layer. In some embodiments, a hole injection layer, an electron blocking layer, or a similar layer is present between the anode and the exciton blocking layer adjacent to the light-emitting layer on the anode side. In some embodiments, a hole injection layer, an electron blocking layer, a hole blocking layer, or a similar layer is present between the cathode and the exciton blocking layer adjacent to the light-emitting layer on the cathode side. In some embodiments, the exciton blocking layer comprises an excited singlet energy and an excited triplet energy, at least one of which is higher than the excited singlet energy and excited triplet energy, respectively, of the light-emitting material.

[0054] (Hole transport layer) The hole transport layer comprises a hole transport material. In some embodiments, the hole transport layer is a single layer. In some embodiments, the hole transport layer has multiple layers. In some embodiments, the hole transport material has one of hole injection or transport properties and electron blocking properties. In some embodiments, the hole transport material is an organic material. In some embodiments, the hole transport material is an inorganic material. Examples of known hole transport materials that can be used in the present invention include, but are not limited to, triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, allylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers (especially thiophene oligomers), or combinations thereof. In some embodiments, the hole transport material is selected from porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds. In some embodiments, the hole transport material is an aromatic tertiary amine compound. Specific examples of preferred compounds that can be used as hole transport materials are given below.

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] (electron transport layer) The electron transport layer comprises an electron transport material. In some embodiments, the electron transport layer is a single layer. In some embodiments, the electron transport layer has multiple layers. In some embodiments, the electron transport material only needs to transport electrons injected from the cathode to the light-emitting layer. In some embodiments, the electron transport material also functions as a hole-blocking material. Examples of electron transport layers that can be used in the present invention include, but are not limited to, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidene methane derivatives, anthraquinodimethanes, anthrone derivatives, oxadiazole derivatives, azole derivatives, azine derivatives, or combinations thereof, or polymers thereof. In some embodiments, the electron transport material is a thiadiazole derivative or a quinoxaline derivative. In some embodiments, the electron transport material is a polymeric material. Specific examples of preferred compounds that can be used as electron transport materials are given below.

[0059] [ka]

[0060] [ka]

[0061] [ka]

[0062] [ka]

[0063] In addition, examples of compounds that can be added to each organic layer are given below, which may be used as stabilizing materials, for example.

[0064] [ka]

[0065] Although the preferred materials that can be used in the organic electroluminescence element are specifically exemplified, the materials that can be used in the present invention are not limited to the following exemplified compounds. In addition, even if a compound is exemplified as a material having a specific function, it can be diverted to a material having other functions.

[0066] (device) In some embodiments, the light emitting materials of the present invention are incorporated into devices, including, but not limited to, OLED bulbs, OLED lamps, television displays, computer monitors, cell phones, and tablets. In one embodiment, an electronic device comprises an OLED having an anode, a cathode, and at least one organic layer comprising an emissive layer between the anode and the cathode, the emissive layer comprising a light-emitting material of the present invention. In some embodiments, the light-emitting layer of the OLED further comprises a fluorescent material that converts triplets to singlets due to the light-emitting material of the present invention phosphor. In some embodiments, the compositions described herein may be incorporated into various photosensitive or photoactivated devices, such as OLEDs or optoelectronic devices. In some embodiments, the compositions may be useful for facilitating charge or energy transfer within the device and / or as hole transport materials. Devices include, for example, organic light-emitting diodes (OLEDs), organic integrated circuits (OICs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic light-emitting transistors (O-LETs), organic solar cells (O-SCs), organic optical sensing devices, organic photoreceptors, organic field-quench devices (O-FQDs), light-emitting electrochemical cells (LECs), or organic laser diodes (O-lasers).

[0067] (Bulb or Lamp) In one embodiment, an electronic device comprises an OLED comprising an anode, a cathode, at least one organic layer comprising an emissive layer between the anode and the cathode, and OLED driver circuitry, wherein the emissive layer comprises a light-emitting material of the present invention. In some embodiments, the device includes OLEDs of different colors. In some embodiments, the device includes an array including a combination of OLEDs. In some embodiments, the combination of OLEDs is a combination of three colors (e.g., RGB). In some embodiments, the combination of OLEDs is a combination of colors that are not red, green, or blue (e.g., orange and yellow-green). In some embodiments, the combination of OLEDs is a combination of two, four, or more colors. In one embodiment, the device is an OLED light, the OLED light comprising: a circuit board having a first side having a mounting surface and an opposing second side, the circuit board defining at least one opening; at least one OLED on the mounting surface, the at least one OLED configured to emit light, the at least one OLED comprising at least one organic layer including an anode, a cathode, and an emissive layer between the anode and the cathode, the emissive layer comprising a light-emitting material of the present invention; a housing for the circuit board; and at least one connector disposed on an end of the housing, the housing and the connector defining a package suitable for attachment to a lighting fixture. In some embodiments, the OLED light has multiple OLEDs mounted on a circuit board such that light is emitted in multiple directions. In some embodiments, some of the light emitted in a first direction is polarized and emitted in a second direction. In some embodiments, a reflector is used to polarize the light emitted in the first direction.

[0068] (Display or Screen) In some embodiments, the luminescent material of the present invention can be used in a screen or display. In some embodiments, the luminescent material of the present invention is deposited onto a substrate using processes such as, but not limited to, vacuum evaporation, deposition, vapor deposition, or chemical vapor deposition (CVD). In some embodiments, the substrate is a photoplate structure useful in two-sided etching to provide pixels of unique aspect ratios. Screens (also called masks) are used in the manufacturing process of OLED displays. The corresponding artwork pattern design allows for very steep narrow tie bars between pixels in the vertical direction and large wide angled openings in the horizontal direction. This allows for fine patterning of pixels required for high resolution displays while optimizing chemical vapor deposition onto the TFT backplane. The internal patterning of the pixel allows for the construction of three-dimensional pixel openings of various aspect ratios in the horizontal and vertical directions. Additionally, the use of imaged "stripes" or halftone circles in the pixel area protects etching in certain areas until those particular patterns are undercut and removed from the substrate. At that point, all pixel areas are treated with similar etch rates, but the depth varies with the halftone pattern. Varying the size and spacing of the halftone patterns allows etching with different protection rates within the pixel, allowing for the localized deep etching required to create steep vertical bevels. The preferred material for the deposition mask is Invar. Invar is a metal alloy that is cold rolled into long thin sheets at steel mills. Invar cannot be electrodeposited onto a rotating mandrel as a nickel mask. A suitable and low-cost method for forming open areas in the deposition mask is by wet chemical etching. In some embodiments, the screen or display pattern is a pixel matrix on a substrate. In some embodiments, the screen or display pattern is fabricated using lithography (e.g., photolithography and e-beam lithography). In some embodiments, the screen or display pattern is fabricated using wet chemical etching. In further embodiments, the screen or display pattern is fabricated using plasma etching.

[0069] (Device manufacturing method) OLED displays are generally manufactured by forming a large mother panel and then cutting the mother panel into cell panels. Usually, each cell panel on the mother panel is formed by forming a thin film transistor (TFT) having an active layer and source / drain electrodes on a base substrate, applying a planarizing film to the TFT, sequentially forming a pixel electrode, an emitting layer, a counter electrode and an encapsulation layer, and cutting the cell panel from the mother panel. OLED displays are generally manufactured by forming a large mother panel and then cutting the mother panel into cell panels. Usually, each cell panel on the mother panel is formed by forming a thin film transistor (TFT) having an active layer and source / drain electrodes on a base substrate, applying a planarizing film to the TFT, sequentially forming a pixel electrode, an emitting layer, a counter electrode and an encapsulation layer, and cutting the cell panel from the mother panel. In another aspect of the invention, there is provided a method for manufacturing an organic light emitting diode (OLED) display, the method comprising: forming a barrier layer on a base substrate of a mother panel; forming a plurality of display units on the barrier layer in units of cell panels; forming an encapsulation layer over each of the display units of the cell panel; and applying an organic film to the interface between the cell panels. In one embodiment, the barrier layer is an inorganic film, for example made of SiNx, and the ends of the barrier layer are covered with an organic film, for example made of polyimide or acrylic. In one embodiment, the organic film assists in soft cutting of the mother panel into cell panels. In some embodiments, the thin film transistor (TFT) layer has a light-emitting layer, a gate electrode, and source / drain electrodes. Each of the multiple display units may have a thin film transistor (TFT) layer, a planarization film formed on the TFT layer, and a light-emitting unit formed on the planarization film, and the organic film applied to the interface is made of the same material as the planarization film and is formed at the same time as the planarization film. In some embodiments, the light-emitting unit is connected to the TFT layer by a passivation layer, the planarization film therebetween, and an encapsulation layer that covers and protects the light-emitting unit. In some embodiments of the manufacturing method, the organic film is not connected to the display unit or the encapsulation layer. Each of the organic film and the planarization film may include one of polyimide and acrylic. In an embodiment, the barrier layer may be an inorganic film. In an embodiment, the base substrate may be formed of polyimide. The method may further include attaching a carrier substrate formed of a glass material to one surface of the base substrate before forming the barrier layer on the other surface of the base substrate formed of polyimide, and separating the carrier substrate from the base substrate before cutting along the interface. In an embodiment, the OLED display is a flexible display. In some embodiments, the passivation layer is an organic film disposed on the TFT layer for covering the TFT layer. In some embodiments, the planarization film is an organic film formed on the passivation layer. In some embodiments, the planarization film is formed of polyimide or acrylic, as is the organic film formed on the edge of the barrier layer. In some embodiments, the planarization film and the organic film are formed simultaneously during the manufacture of an OLED display. In some embodiments, the organic film may be formed on the edge of the barrier layer, so that a portion of the organic film directly contacts the base substrate, and the remaining portion of the organic film contacts the barrier layer while surrounding the edge of the barrier layer. In some embodiments, the light-emitting layer comprises a pixel electrode, a counter electrode, and an organic light-emitting layer disposed between the pixel electrode and the counter electrode, hi some embodiments, the pixel electrode is coupled to a source / drain electrode of the TFT layer. In one embodiment, when a voltage is applied to the pixel electrode through the TFT layer, a suitable voltage is formed between the pixel electrode and the counter electrode, which causes the organic light-emitting layer to emit light, thereby forming an image. Hereinafter, an image-forming unit having a TFT layer and a light-emitting unit is referred to as a display unit. In some embodiments, the encapsulation layer that covers the display units and prevents the penetration of external moisture may be formed into a thin-film encapsulation structure in which organic films and inorganic films are alternately laminated. In some embodiments, the encapsulation layer has a thin-film encapsulation structure in which multiple thin films are laminated. In some embodiments, the organic film applied to the interface portion is disposed at an interval with each of the multiple display units. In some embodiments, the organic film is formed in such a manner that a portion of the organic film directly contacts the base substrate, and the remaining portion of the organic film contacts the barrier layer while surrounding the end of the barrier layer. In one embodiment, the OLED display is flexible and uses a flexible base substrate formed of polyimide, hi some embodiments, the base substrate is formed on a carrier substrate formed of a glass material, and then the carrier substrate is separated. In some embodiments, the barrier layer is formed on the surface of the base substrate opposite the carrier substrate. In one embodiment, the barrier layer is patterned according to the size of each cell panel. For example, the base substrate is formed on all surfaces of the mother panel, while the barrier layer is formed according to the size of each cell panel, thereby forming grooves at the interfaces between the barrier layers of the cell panels. Each cell panel can be cut along the grooves. In an embodiment, the manufacturing method further includes a step of cutting along the interface, a groove is formed in the barrier layer, and at least a portion of the organic film is formed in the groove, and the groove does not penetrate the base substrate. In an embodiment, the TFT layer of each cell panel is formed, and a passivation layer, which is an inorganic film, and a planarization film, which is an organic film, are disposed on the TFT layer to cover the TFT layer. At the same time that the planarization film, for example made of polyimide or acrylic, is formed, the groove in the interface is covered with an organic film, for example made of polyimide or acrylic. This prevents cracks from occurring when each cell panel is cut along the groove at the interface by having the organic film absorb the impact that occurs. That is, if all the barrier layers are completely exposed without the organic film, when each cell panel is cut along the groove at the interface, the impact that occurs will be transmitted to the barrier layer, thereby increasing the risk of cracks. However, in an embodiment, the groove in the interface between the barrier layers is covered with an organic film to absorb the impact that would otherwise be transmitted to the barrier layer, so that each cell panel can be cut softly and prevent cracks from occurring in the barrier layer. In one embodiment, the organic film and the planarization film covering the groove of the interface are spaced apart from each other. For example, when the organic film and the planarization film are connected to each other as one layer, external moisture may penetrate into the display unit through the planarization film and the remaining part of the organic film, so the organic film and the planarization film are spaced apart from each other so that the organic film is spaced apart from the display unit. In an embodiment, a display unit is formed by forming a light-emitting unit, and an encapsulation layer is disposed on the display unit to cover the display unit. Thus, after the mother panel is completely manufactured, the carrier substrate carrying the base substrate is separated from the base substrate. In an embodiment, when a laser beam is irradiated onto the carrier substrate, the carrier substrate is separated from the base substrate due to the difference in thermal expansion coefficient between the carrier substrate and the base substrate. In some embodiments, the mother panel is cut into individual cell panels. In some embodiments, the mother panel is cut along the interface between the cell panels using a cutter. In some embodiments, the grooves of the interface along which the mother panel is cut are covered with an organic film, which absorbs shock during cutting. In some embodiments, the barrier layer is prevented from cracking during cutting. In one embodiment, the method reduces product defect rates and stabilizes product quality. Another embodiment is an OLED display having a barrier layer formed on a base substrate, a display unit formed on the barrier layer, an encapsulation layer formed on the display unit, and an organic film applied to the edges of the barrier layer. EXAMPLES

[0070] General information about the analytical method: The features of the present invention will be described more specifically with reference to the following examples. The materials, steps, procedures, etc. shown below can be appropriately modified without departing from the essence of the invention. Therefore, the scope of the present invention is not to be construed as being limited to the specific embodiments shown below. The samples were characterized using NMR (Bruker 500MHz Nuclear Magnetic Resonance), LC / MS (Waters Liquid Chromatography Mass Spectrometer), AC3 (Riken Keiki), high performance UV / Vis / NIR spectrophotometer (PerkinElmer Lambda950), fluorescence spectrophotometer (Horiba FluoroMax-4), photonic multichannel analyzer (Hamamatsu Photonics PMA-12 C10027-01), absolute PL quantum yield measurement system (Hamamatsu Photonics C11347), automated current-voltage-luminance measurement system (Systems Giken ETS-170), lifetime measurement system (Systems Giken EAS-26C) and streak camera (Hamamatsu Photonics model C4334).

[0071] (Example 1) Preparation and evaluation of thin film 1 Vacuum degree 10 -3 Under conditions of 0.1 Pa or less, a donor compound TrisPCz, an acceptor compound SF3-TRZ, and a coordinating compound PYD2Cz were evaporated onto a quartz substrate in a mass ratio of 1:1:1 to prepare a thin film DAN with a thickness of 70 nm. Thin film D was prepared by depositing only TrisPCz under the same conditions. Under the same conditions, thin film A was prepared by depositing only SF3-TRZ. Under the same conditions, thin film N was prepared by depositing only PYD2Cz. Under the same conditions, thin film DA was prepared by vapor deposition of TrisPCz and SF3-TRZ in a mass ratio of 1:1. Under the same conditions, thin film DN was prepared by vapor deposition of TrisPCz and PYD2Cz in a mass ratio of 1:1. Under the same conditions, thin film AN was prepared by depositing SF3-TRZ and PYD2Cz in a mass ratio of 1:1.

[0072] 2 shows the energy levels of the compounds used in the light-emitting layer of Example 1. The light-emitting material that satisfies the relationships of formulas (A), (B1) and (B2) is thin film DAN. The prepared thin films were irradiated with light of 300 nm wavelength at 300 K and the emission spectra were measured, and the results are shown in Figure 3. Figure 3 shows that the donor compound TrisPCz and the acceptor compound SF3-TRZ form an exciplex and emit light, and that the emission spectrum due to the exciplex does not change even when the coordinating compound PYD2Cz is further added. The photoluminescence quantum yield (PLQY) was measured to be 31% for the thin film DA and 46% for the thin film DAN, confirming that the emission efficiency of exciplexes is greatly improved by further adding a coordinating compound.

[0073] (Example 2) Preparation and evaluation of thin film 2 The mass ratio of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the adjusting compound PYD2Cz was changed as shown in the table below, and the rest of the thin film was formed by the same procedure as in Example 1. When the emission spectrum was measured in the same manner as in Example 1, the emission spectrum from 300 to 700 nm was the same as that of the thin film DAN of Example 1. In addition, when the transient decay curves were compared, it was confirmed that the higher the mass ratio of the adjusting compound PYD2Cz, the longer the life of the delayed fluorescence tends to be. Furthermore, when the luminescence quantum yield (PLQY) was compared, it was confirmed that the higher the mass ratio of the adjusting compound PYD2Cz, the higher the luminescence quantum yield tends to be. [Table 1]

[0074] (Example 3) Preparation and evaluation of thin film 3 A thin film having the mass ratio shown in the table below was formed by the same procedure as in Example 2, except that mCBP was used as the adjusting compound. The energy levels of each compound used in the light-emitting layer of Example 3 are shown in Figure 4. It was also confirmed that for the thin film using mCBP as the adjusting compound, the higher the mass ratio of the adjusting compound, the longer the delayed fluorescence lifetime and the higher the luminescence quantum yield tended to be. [Table 2]

[0075] Example 4: Fabrication and evaluation of organic electroluminescence device Each thin film was deposited on a glass substrate with an anode made of indium tin oxide (ITO) with a thickness of 50 nm by vacuum deposition at a vacuum degree of 10. -5 Pa. First, HAT-CN was formed on ITO to a thickness of 10 nm, NPD was formed on it to a thickness of 30 nm, and TrisPCz was formed to a thickness of 10 nm. Next, the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the adjusting compound PYD2Cz were co-evaporated from different evaporation sources in a mass ratio of 1:1:1 to form a 30 nm thick light-emitting layer. Next, SF3-TRZ was formed to a thickness of 10 nm, and SF3-TRZ and Liq were formed on it in a mass ratio of 7:3 to a thickness of 30 nm. Furthermore, lithium fluoride (LiF) was evaporated to a thickness of 2.0 nm, and then aluminum (Al) was evaporated to a thickness of 100 nm to form a cathode, and an organic electroluminescence device (element DAN) was fabricated. In addition, an organic electroluminescence device (element DA) was fabricated by the same procedure, with the only change being that the light-emitting layer was formed by co-evaporating the donor compound TrisPCz and the acceptor compound SF3-TRZ in a mass ratio of 1:1. In addition, an organic electroluminescence device (element DANE) was fabricated by the same procedure, except that the donor compound TrisPCz, the acceptor compound SF3-TRZ, the adjustment compound PYD2Cz, and the light-emitting compound 4DPA-Pyr were co-evaporated from different evaporation sources to form an emission layer. At this time, the mass ratio of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the adjustment compound PYD2Cz was 1:1:1. In addition, the light-emitting compound 4DPA-Pyr was 1 mass% with respect to the total amount of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the adjustment compound PYD2Cz. Furthermore, an organic electroluminescence device (DAE) was fabricated by the same procedure, except that the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the light-emitting compound 4DPA-Pyr were co-evaporated from different deposition sources to form an emitting layer. At this time, the mass ratio of the donor compound TrisPCz to the acceptor compound SF3-TRZ was 1:1. The amount of the light-emitting compound 4DPA-Pyr was 1 mass% of the total amount of the donor compound TrisPCz and the acceptor compound SF3-TRZ.

[0076] The results of measuring the emission spectra of the four fabricated elements are shown in Figure 5. The emission spectra of elements DAN and DA from 300 to 700 nm were the same, and the emission spectra of elements DANE and DAE from 300 to 700 nm were the same. The maximum emission wavelengths of elements DANE and DAE were slightly shorter than the maximum emission wavelengths of elements DAN and DA. On the other hand, the half-widths of elements DANE and DAE were narrower than those of elements DAN and DA. The time until the emission intensity decreased to 95% (LT95) was the longest for element DANE. The LT95 of element DANE was 3.0 times that of element DAE, and it was confirmed that the emission lifetime was dramatically extended by adding the adjusting compound.

[0077] (Example 5) Solubility test A solubility test was carried out in 1 ml of toluene for a mixture of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the adjusting compound PYD2Cz, where the masses of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the adjusting compound PYD2Cz were 4.5 mg, 4.5 mg, and 1.0 mg, respectively (mixture DAN1). Furthermore, the mass ratio of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the mixed compound PYD2Cz was changed as shown in the table below, and the solubility test was carried out by the same procedure as for composition DAN1 (mixture DAN2 and mixture DAN3). It was visually confirmed that all compositions were dissolved. This confirmed that the combination of the present invention can be applied to a coating type element. [Table 3]

[0078] [ka] [Industrial Applicability]

[0079] The light-emitting material of the present invention is excellent in at least one of luminous efficiency and luminous life. Therefore, the light-emitting material of the present invention can be effectively used as a charge transport material for organic light-emitting diodes such as organic electroluminescence devices, and it is possible to provide an organic light-emitting diode that realizes at least one of high luminous efficiency and long luminous life. Therefore, the present invention has a high industrial applicability. [Explanation of symbols]

[0080] 1 Board 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Light-emitting layer 6 Electron transport layer 7 Cathode

Claims

1. In addition to the donor compound and the acceptor compound that form an exciplex, the compound further contains a coordinating compound other than the donor compound and the acceptor compound, and satisfies the relationships of the following formulae (A), (B1), and (B2): the adjusting compound is a compound selected from the group consisting of compounds having a donor site and an acceptor site in the molecule, and compounds having two or more donor sites and a linking group linking them in the molecule, the linking group being a substituted or unsubstituted arylene group, a substituted or unsubstituted alkenylene group, a substituted or unsubstituted alkynylene group, or a group in which two or more groups selected from a substituted or unsubstituted arylene group, a substituted or unsubstituted alkenylene group, and a substituted or unsubstituted alkynylene group are linked together; A light-emitting material, wherein the content of the adjusting compound is 30% by mass or more and 60% by mass or less, when the entire light-emitting material is taken as 100% by mass. Formula (A) HOMO(D)>HOMO(N)>HOMO(A) Formula (B1) LUMO(D)>LUMO(N)+0.1eV Formula (B2) LUMO(N)>LUMO(A) [In formula (A), formula (B1) and formula (B2), HOMO(D) represents the energy level of the HOMO (Highest Occupied Molecular Orbital) of the donor compound, HOMO(A) represents the energy level of the HOMO of the acceptor compound, HOMO(N) represents the energy level of the HOMO of the coordinating compound, LUMO(D) represents the energy level of the LUMO (Lowest Unoccupied Molecular Orbital) of the donor compound, LUMO(A) represents the energy level of the LUMO of the acceptor compound, and LUMO(N) represents the energy level of the LUMO of the coordinating compound.]

2. The light-emitting material according to claim 1 , further satisfying the following formula (C): Formula (C) HOMO(D)≧HOMO(A)+0.6eV

3. 3. The luminescent material according to claim 1, wherein the luminescence intensity from the exciplex is at least 10 times that from the coordinating compound.

4. The luminescent material according to any one of claims 1 to 3, further comprising a luminescent compound.

5. A persistent fluorescent material comprising the luminescent material according to any one of claims 1 to 4.

6. An organic light emitting diode (OLED) comprising the light emitting material according to any one of claims 1 to 4.

7. An organic light emitting diode (OLED) comprising an anode, a cathode, and at least one organic layer comprising a light emitting layer between the anode and the cathode, An organic light emitting diode (OLED) in which the light emitting layer comprises the light emitting material according to any one of claims 1 to 4.

8. An organic light emitting diode (OLED) comprising an anode, a cathode, and at least one organic layer comprising a light emitting layer between the anode and the cathode, An organic light emitting diode (OLED) wherein the light emitting layer comprises the light emitting material of claim 4.

9. A screen or display comprising a luminescent material according to any one of claims 1 to 4.

10. 1. A method of making an OLED display, the method comprising: forming a barrier layer on a base substrate of a mother panel; forming a plurality of display units on the barrier layer in units of cell panels; forming an encapsulation layer over each of the display units of the cell panel; applying an organic film to the interface between the cell panels; The display unit includes a thin film transistor layer and a planarization film, and a light-emitting unit including a pixel electrode, a light-emitting layer and a counter electrode; The light-emitting layer comprises the light-emitting material according to any one of claims 1 to 4. method.

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