Luminescent material, delayed phosphor, organic light emitting diode, display screen, display and method for manufacturing the display

Abstract

The present invention provides a luminescent material having improved luminescent efficiency or luminescent lifetime. The luminescent material comprises, in addition to a donor compound D and an acceptor compound A that form an exciplex, a regulating compound N, and the following conditions: HOMO(D)>HOMO(N)>HOMO(A), LUMO(D)>LUMO(N)+0.1eV, and LUMO(N)>LUMO(A).

Description

Technical Field

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

[0002] Research is actively underway to improve the luminous efficiency of light-emitting devices. In particular, various studies are underway to develop new light-emitting materials that can efficiently emit light. Among these, light-emitting materials using exciplexes formed by combining an acceptor compound and a donor compound have the potential to reduce the energy difference ΔE between the excited triplet state and the excited singlet state by combining appropriate acceptor and donor compounds, compared to light-emitting materials that have both an acceptor and a donor in the same molecule. st , so its use as a delayed fluorescence material is being studied.

[0003] For example, Patent Document 1 proposes a delayed fluorescent material comprising a mixture of an acceptor compound and a donor compound, and specifies the excited triplet energy T1 of the acceptor compound as A and |LUMO A |, excited triplet state energy T1 of the donor compound D and|HOMO D |, the magnitude or relationship of the excited singlet energy S1 of the exciplex. In the same document, it is confirmed that high luminous efficiency can be obtained in a light-emitting device using this delayed fluorescence material.

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-193352 Summary of the Invention

[0007] Technical issues to be solved by the invention

[0008] As described in Patent Document 1, the luminescent material for forming an exciplex is provided as a mixture of a donor compound and an acceptor compound. In order to improve the luminous efficiency and luminous lifetime of the luminescence involved in the exciplex, research on providing new combinations of donor compounds and acceptor compounds has been mainly carried out so far. However, in order to propose a new combination of donor compounds and acceptor compounds to actually confirm the effect, a lot of trial and error and experiments are required. Moreover, even if a feasible combination of donor compounds and acceptor compounds is found through such trial and error and experiments, if conditions such as manufacturing cost, safety, and environmental adaptability cannot be solved, there is still no hope for practical application. Therefore, it takes a lot of cost and time to achieve practical application by improving the efficiency and lifetime of the luminescence involved in the exciplex.

[0009] In view of such circumstances, the present inventors conducted studies with the aim of improving the efficiency and lifetime of light emission associated with exciplexes by a simple method.

[0010] Means for solving technical problems

[0011] As a result of intensive research, the present inventors have discovered the following, leading to the provision of the present invention, namely, in addition to the donor compound and acceptor compound that form the exciplex, the material also contains a regulating compound that satisfies a specific energy relationship, thereby improving the luminous efficiency and luminous lifetime of the luminescent material.

[0012] The present invention at least includes the following technical contents.

[0013] [1] A light-emitting material comprising, in addition to a donor compound and an acceptor compound that form an exciplex, a regulating compound that is different from the donor compound and the acceptor compound, and satisfying the relationship of the following formulas (A), (B1), and (B2).

[0014] Formula (A)HOMO(D)>HOMO(N)>HOMO(A)

[0015] Formula (B1)LUMO(D)>LUMO(N)+0.1eV

[0016] Formula (B2) LUMO(N)>LUMO(A)

[0017] [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 modulator 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 modulator compound.]

[0018] [2] The light-emitting material according to [1], which further satisfies the relationship of the following formula (C).

[0019] Formula (C) HOMO(D)≥HOMO(A)+0.6eV.

[0020] [3] The light-emitting material according to [1], which further satisfies the relationship between the following formulas (D) and (E).

[0021] Formula (D)T1(D)<T1(N)

[0022] Formula (E) T1(A)<T1(N)

[0023] 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 regulating compound.

[0024] [4] The light-emitting material according to any one of [1] to [3], wherein

[0025] The content of the regulating compound is 30% by mass or more.

[0026] [5] The light-emitting material according to any one of [1] to [4], wherein

[0027] The emission intensity from the exciplex is 10 times greater than that from the modulating compound.

[0028] [6] The light-emitting material according to any one of [1] to [5], further comprising a light-emitting compound.

[0029] [7] The luminescent material according to [6], wherein

[0030] The emission intensity from the light-emitting compound is 10 times or more higher than the emission intensity from the exciplex.

[0031] [8] The luminescent material according to [6], wherein

[0032] The luminescence intensity from the luminescent compound is 50 times greater than the luminescence intensity from the regulating compound.

[0033] [9] A delayed phosphor comprising the light-emitting material according to any one of [1] to [8].

[0034]

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

[0035]

[11] 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, wherein:

[0036] The light-emitting layer contains the light-emitting material described in any one of [1] to [5].

[0037]

[12] 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, wherein:

[0038] The light-emitting layer contains the light-emitting material described in any one of [6] to [8].

[0039]

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

[0040]

[14] A method for manufacturing an OLED display, comprising:

[0041] forming a barrier layer on a base substrate of a motherboard;

[0042] forming a plurality of display units in a unit panel unit on the barrier layer;

[0043] forming an encapsulation layer on each of the display units of the unit panel; and

[0044] A step of applying an organic film to the interface between the unit plates;

[0045] The organic film contains the light-emitting material described in any one of [1] to [8].

[0046] Effects of the Invention

[0047] The present invention provides an exciplex-related luminescent material with improved luminescence efficiency and luminescence lifetime. Furthermore, the present invention provides a delayed phosphor, an organic light-emitting diode, a display, and a monitor with improved luminescence efficiency and luminescence lifetime. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a schematic cross-sectional view showing an example of the layer structure of an organic electroluminescent device.

[0049] Figure 2 This is a diagram showing the energy levels of the compounds used in the light-emitting layer of Example 1.

[0050] Figure 3 1 is the emission spectrum of each element in Example 1.

[0051] Figure 4 This is a diagram showing the energy levels of the compounds used in the light-emitting layer of Example 3.

[0052] Figure 5 This is the emission spectrum of each element in Example 4. DETAILED DESCRIPTION

[0053] Hereinafter, the content of the present invention will be described in detail. The constituent elements described below are described based on representative embodiments or specific examples of the present invention, but the present invention is not limited to these embodiments or specific examples. In addition, in the specification, the numerical range represented by "to" represents a range including the numerical values ​​before and after the "to" as the lower limit and the upper limit.

[0054] [Luminescent Material of the Present Invention]

[0055] (Energy Levels of Each Compound Contained in the Luminescent Material)

[0056] The luminescent material of the present invention comprises a donor compound that forms an exciplex, an acceptor compound that forms the exciplex, and a modulator compound different from the donor and acceptor compounds. Furthermore, the donor, acceptor, and modulator compounds contained in the luminescent material of the present invention satisfy the relationships of the following formulas (A), (B1), and (B2).

[0057] Formula (A)HOMO(D)>HOMO(N)>HOMO(A)

[0058] Formula (B1)LUMO(D)>LUMO(N)+0.1eV

[0059] Formula (B2) LUMO(N)>LUMO(A)

[0060] 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 acceptor compound, HOMO(N) represents the energy level of the HOMO of the modulator 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 modulator compound. In the present invention, these energy levels are expressed in eV.

[0061] The HOMO energy level and the LUMO energy level in the present invention are determined by photoelectron spectroscopy in the atmosphere. In the present invention, the HOMO energy level and the LUMO energy level are measured using AC-3 manufactured by RIKEN KEIKI Co., Ltd.

[0062] HOMO(N) may be greater than HOMO(A) and less than HOMO(D). In one embodiment of the present invention, HOMO(N) is closer to HOMO(A) than HOMO(D). In another embodiment of the present invention, HOMO(N) is closer to HOMO(D) than HOMO(A). In another embodiment of the present invention, HOMO(N) is within the following range.

[0063] [Formula 1]

[0064]

[0065] In another embodiment of the present invention, HOMO(N) is within the following range.

[0066] [Formula 2]

[0067]

[0068] LUMO(N) is larger than LUMO(A) and smaller than LUMO(D) by at least 0.1eV. LUMO(N) is preferably smaller than LUMO(D) by at least 0.2eV. In one embodiment of the present invention, LUMO(N) is smaller than LUMO(D) by at least 0.3eV. In another embodiment of the present invention, LUMO(N) is smaller than LUMO(D) by at least 0.4eV. When LUMO(N) is smaller than LUMO(D) by at least 0.1eV, 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.

[0069] [Formula 3]

[0070]

[0071] In another embodiment of the present invention, LUMO(N) is within the following range.

[0072] [Formula 4]

[0073]

[0074] In one embodiment of the present invention, HOMO (D) and HOMO (A) satisfy the following formula.

[0075] Formula (C) HOMO(D)≥HOMO(A)+0.6eV.

[0076] In another embodiment of the present invention, HOMO (D) and HOMO (A) satisfy the following formula.

[0077] Formula (C1) HOMO(D) ≥ HOMO(A) + 0.7 eV

[0078] In another embodiment of the present invention, HOMO (D) and HOMO (A) satisfy the following formula.

[0079] Formula (C2) HOMO(D) ≥ HOMO(A) + 0.8 eV

[0080] The donor compound, acceptor compound, and modulator compound contained in the light-emitting material of the present invention preferably have the lowest excited triplet energy levels satisfying the following formulae (D) and (E).

[0081] Formula (D)T1(D)<T1(N)

[0082] Formula (E) T1(A)<T1(N)

[0083] 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 modulator compound.

[0084] In one embodiment of the present invention, the lowest excited triplet energy level satisfies the following formula.

[0085] Formula (D1)T1(D)+0.2eV<T1(N)

[0086] Formula (E1) T1(A)+0.2eV<T1(N)

[0087] In another embodiment of the present invention, the lowest excited triplet energy level satisfies the following formula.

[0088] Formula (D2) T1(D) + 0.4eV < T1(N)

[0089] Formula (E2) T1(A)+0.4eV<T1(N)

[0090] The lowest excited triplet energy level T1(N) of the adjustment compound contained in the light-emitting 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, and may be, for example, -3.2 eV or more.

[0091] (Donor compound contained in the light-emitting material)

[0092] 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.

[0093] In a preferred embodiment of the present invention, a donor compound having the following skeleton is used.

[0094] [Chemical Formula 1]

[0095]

[0096] The hydrogen atoms of the skeleton may be substituted with substituents. The number of substituents may be 0, 1, 2, 3, or 4 or more. Furthermore, when substituted with two or more substituents, these 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 silanyl.

[0097] The molecular weight of the donor compound is, for example, selected from the range of 200 or more, 250 or more, or 300 or more, or can be selected from the range of 2000 or less, 1000 or less, or 700 or less.

[0098] Specific examples of the donor compound are given below, but the donor compounds that can be used in the present invention are not to be construed as being limited to the following exemplary compounds.

[0099] [Chemical Formula 2]

[0100]

[0101] (Acceptor compound contained in the light-emitting material)

[0102] The acceptor compound contained in the light-emitting material of the present invention is a compound that forms an exciplex together with the donor compound. In the present invention, a known acceptor compound that forms an exciplex can be used.

[0103] In a preferred embodiment of the present invention, an acceptor compound having the following skeleton is used.

[0104] [Chemical Formula 3]

[0105]

[0106] The hydrogen atoms of the skeleton may be substituted with substituents. The number of substituents may be 0, 1, 2, 3, or 4 or more. Furthermore, when substituted with two or more substituents, these 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 silanyl.

[0107] The molecular weight of the acceptor compound is, for example, selected from the range of 200 or more, 250 or more, or 300 or more, or can be selected from the range of 2000 or less, 1000 or less, or 700 or less.

[0108] Specific examples of the acceptor compound are given below, but the acceptor compounds that can be used in the present invention are not to be construed as being limited to the following exemplary compounds.

[0109] [Chemical Formula 4-1]

[0110]

[0111] [Chemical Formula 4-2]

[0112]

[0113] In the luminescent material of the present invention, an exciplex is formed by a donor compound and an acceptor compound. The exciplex is an association compound of an acceptor compound and a donor compound, and when excitation energy is supplied, electrons are transferred from the donor compound to the acceptor compound and converted into an excited state. The luminescent material of the present invention can emit light from the exciplex, and when it also contains the luminescent compound described later, it can also emit light from the luminescent compound, or it can emit light from the exciplex and the luminescent material simultaneously. The exciplex preferably emits light in the visible region, for example, it can emit blue, green, yellow, red and other light. In addition, the exciplex preferably emits delayed fluorescence, and can also emit conventional fluorescence. The difference ΔE between the lowest excited singlet energy and the lowest excited triplet energy of the exciplex ST It is preferably 0.3 eV or less, more preferably 0.2 eV or less, further preferably 0.1 eV or less, further preferably 0.05 eV or less, and particularly preferably 0.02 eV or less.

[0114] In one embodiment of the present invention, when the emission intensity from the light-emitting material is set to 100%, the emission intensity from the exciplex can be adjusted to, for example, within a range of 0.1% or more, 1% or more, 10% or more, 25% or more, 50% or more, 75% or more, 90% or more, or 99% or more, or 100%. Furthermore, it can be adjusted to 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 sources other than the exciplex and the light-emitting compound can be adjusted to within a range of 20% or less, 10% or less, 5% or less, 1% or less, 0.1% or less, or 0%.

[0115] (Modulating compound contained in the luminescent material)

[0116] The structure of the modulator compound contained in the light-emitting material of the present invention is not particularly limited as long as it satisfies Formula (A), Formula (B1) and Formula (B2).

[0117] In one embodiment of the present invention, the regulating compound is a compound having a donor site and an acceptor site in the molecule. When the donor site is set to D and the acceptor site is set to A, the compound having

[0118] DA

[0119] DAD

[0120] DADAD

[0121] ADA

[0122] ADADA

[0123] (A)mD

[0124] (D)nA

[0125] When there are two or more Ds in the molecule, they may be the same or different, and when there are two or more As in the molecule, they may be the same or different. m represents an integer of 3 or more and up to the maximum number of substitutable Ds, and n represents an integer of 3 or more and up to the maximum number of substitutable As.

[0126] As the donor site D, a group with a negative Hammett's σp value can be used. And as the acceptor site A, a group with a positive Hammett's σp value can be used. p The "value" is a value proposed by L. P. Hammett, which quantifies the effect of the substituent on the reaction rate or equilibrium of the para-substituted benzene derivative. Specifically, the following equation is established between the substituent in the para-substituted benzene derivative and the reaction rate constant or equilibrium constant:

[0127] log(K / K0)=ρσ p

[0128] or

[0129] log(K / K0)=ρσ p

[0130] The constant (σ) unique to the substituent in p ). In the above formula, k represents the rate constant of the benzene derivative without substituents, k0 represents the rate constant of the benzene derivative substituted with a substituent, K represents the equilibrium constant of the benzene derivative without substituents, K0 represents the equilibrium constant of the benzene derivative substituted with a substituent, and ρ represents the reaction constant determined according to the type and conditions of the reaction. p For explanation of "value" and the numerical value of each substituent, reference can be made to σ in Hansch, C. et.al., Chem. Rev., 91, 165-195 (1991). p Value-related records.

[0131] In another embodiment of the present invention, the regulating compound is a compound having two or more donor sites and a linker connecting these sites in the molecule. For example, when the donor site is set to D and the linker is set to L or L', an example of a compound having

[0132] DLD

[0133] DLDLD

[0134] (D)n-L'

[0135] A compound having a structure represented by . When two or more Ds are present in the molecule, they may be the same or different, and when two or more Ls are present in the molecule, they may be the same or different. n represents an integer of 3 or greater and up to the maximum number of substitutable L's, and L' represents an n-valent linking group.

[0136] 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 include groups formed by linking two or more groups selected from substituted or unsubstituted arylene groups, substituted or unsubstituted alkenylene groups, and substituted or unsubstituted alkynylene groups. The arylene group mentioned here can 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. Specific examples include 1,4-phenylene, 1,3-phenylene, 1,2-phenylene, 1,8-naphthylene, 1,4-naphthylene, 1,2-naphthylene, 2,3-naphthylene, 2,6-naphthylene, 2,7-naphthylene, 9,10-anthracenylene, 2,3-anthracenylene, 2,6-anthracenylene, 2,7-anthracenylene, 1,8-anthracenylene, and 1,5-anthracenylene. The alkenylene group mentioned here can be selected from the range of 2 to 20 carbon atoms, 2 to 10 carbon atoms, 2 to 6 carbon atoms, and 2 to 4 carbon atoms. Specific examples include -(CR 1 =CR 2 ) n1 -represented by a group. 1 and R 2 Each independently represents a hydrogen atom or a substituent. Examples of substituents include alkyl groups having 1 to 10 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, alkynyl groups having 2 to 10 carbon atoms, and aryl groups having 6 to 30 carbon atoms. n1 is an integer from 1 to 10. The alkynylene group mentioned here can be selected from groups having 2 to 20 carbon atoms, 2 to 10 carbon atoms, 2 to 6 carbon atoms, and 2 to 4 carbon atoms. A specific example is vinyl. Examples of substituents for the arylene and alkenylene groups that can be used as linkers L and L' include alkyl groups having 1 to 10 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, alkynyl groups having 2 to 10 carbon atoms, and aryl groups having 6 to 30 carbon atoms.

[0137] The molecular weight of the regulating compound is, for example, selected from the range of 200 or more, 250 or more, or 300 or more, or can be selected from the range of 2000 or less, 1000 or less, or 700 or less.

[0138] Specific examples of the regulating compound are given below, but the regulating compounds that can be used in the present invention are not to be construed as being limited to the following exemplified compounds.

[0139] [Chemical Formula 5]

[0140]

[0141] (Luminescent Compound)

[0142] The luminescent material of the present invention may contain a luminescent compound as a compound other than the donor compound, the acceptor compound and the modulator compound. The luminescent compound mentioned here does not belong to the modulator compound satisfying formula (A), formula (B1) and formula (B2).

[0143] The luminescent compound included in the luminescent 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 luminescent compounds may be included. In this case, energy transfer may occur from one luminescent compound to another, or the two or more luminescent compounds may each directly transfer energy from the exciplex.

[0144] The light-emitting compound preferably emits light in the visible region, for example, blue, green, yellow, red, etc. Furthermore, the light-emitting compound may emit fluorescence or phosphorescence, or may emit delayed fluorescence.

[0145] When a luminescent compound is included, the luminescent material of the present invention may be luminescent only from the luminescent compound, or may be luminescent from other substances of the luminescent compound. In the latter case, the luminescence intensity from the luminescent compound may be the greatest, or the luminescence intensity from the luminescent compound may be less 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 or content of the luminescent material. When the luminescence intensity from the luminescent material is set to 100%, the luminescence intensity from the luminescent compound can be adjusted to, for example, be within the range of 0.1% or more, 1% or more, 10% or more, 25% or more, 50% or more, 75% or more, 90% or more, or 99% or more. Furthermore, it can also be adjusted to be within the range of less than 95%, less than 70%, less than 40%, less than 30%, less than 10%, or less than 1%. 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 of the luminescence intensity from the exciplex, and may also be 0.5 times or less, 0.1 times or less, or 0.01 times or less. Furthermore, 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 of the luminescence intensity from the modulator compound.

[0146] Hereinafter, light-emitting materials that can be used as the light-emitting material of the present invention are exemplified. However, the light-emitting materials that can be used in the present invention are not to be construed as being limited to the following compounds.

[0147] [Chemical Formula 6]

[0148]

[0149] (Composition of Luminescent Material)

[0150] The content of each of the donor compound, the acceptor compound, and the regulating compound contained in the luminescent material is not particularly limited as long as it can emit light. When the total amount of the luminescent material is set to 100% by mass, the content of each compound can be selected, for example, within the range of 0.01 to 99.99% by mass. Each compound can, for example, be independently selected within the range of 0.1% by mass, 1% by mass, 5% by mass, 10% by mass, 30% by mass, 50% by mass, 70% by mass, or 90% by mass, or can be selected within the range of 80% by mass or less, 60% by mass or less, 40% by mass or less, 20% by mass or less, 10% by mass or less, 5% by mass or less, or 1% by mass or less.

[0151] In one embodiment of the present invention, the content of the regulating 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 regulating compound is greater than or equal to the total content of the donor compound and the acceptor compound.

[0152] In another embodiment of the present invention, the content of the regulating compound is less than the total content of the donor compound and the acceptor compound. In one embodiment of the present invention, the content of the regulating compound is less than the content of the donor compound and less than the content of the acceptor compound.

[0153] In the luminescent material of the present invention, the content of the donor compound may be the same as that of the acceptor compound, or the content of the donor compound may be more than the acceptor compound (for example, the donor compound may be more than 2 times, more than 4 times, or more than 10 times that of the acceptor compound), or the acceptor compound may be more than the donor compound (for example, the acceptor compound may be more than 2 times, more than 4 times, or more than 10 times that of the donor compound).

[0154] In the luminescent material of the present invention, the content of the donor compound and the content of the regulating compound may be the same, or the donor compound may be more than the regulating compound (for example, the donor compound may be more than 2 times, more than 4 times, or more than 10 times the regulating compound), or the regulating compound may be more than the donor compound (for example, the regulating compound may be more than 2 times, more than 4 times, or more than 10 times the donor compound).

[0155] In the luminescent material of the present invention, the content of the acceptor compound and the content of the regulating compound may be the same, or the acceptor compound may be more than the regulating compound (for example, the acceptor compound may be more than 2 times, more than 4 times, or more than 10 times the regulating compound), or the regulating compound may be more than the acceptor compound (for example, the regulating compound may be more than 2 times, more than 4 times, or more than 10 times the acceptor compound).

[0156] The luminescent material of the present invention tends to improve at least one of luminous efficiency and luminous lifetime by increasing the content of the regulating compound. In addition, the luminescent material of the present invention tends to extend the lifetime of delayed fluorescence by increasing the content of the regulating compound.

[0157] When the light-emitting material of the present invention contains a light-emitting compound as a compound other than a donor compound, an acceptor compound and a regulating compound, its content can be selected, for example, within the range of 0.01 mass %, 0.1 mass %, 1 mass %, 3 mass %, 5 mass %, 10 mass %, or 20 mass %, or can be selected within the range of 30 mass %, 15 mass %, 10 mass %, 5 mass %, or 1 mass %.

[0158] 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 emitted from the light-emitting material of the present invention, the light emission intensity derived from the exciplex formed by the donor compound and the acceptor compound is the highest.

[0159] The luminescent material of the present invention may contain a compound that is not a donor compound, an acceptor compound, a modulator compound, or a luminescent compound. The luminescent material of the present invention may consist solely of a donor compound, an acceptor compound, a modulator compound, and a luminescent compound.

[0160] (definition)

[0161] Unless otherwise defined in this specification, the scientific and technical terms used in this application should have the meanings commonly understood by those skilled in the art. Generally speaking, the nomenclature and techniques related to the chemical substances described in this specification are well known and commonly used in the art.

[0162] The term "acyl" is art-recognized and refers to a group represented by the general formula hydrocarbylC(O)-, preferably alkylC(O)-.

[0163] The term "amido" is art-recognized and refers to an amino group substituted with an acyl group, as represented, for example, by the formula hydrocarbyl C(O)NH-.

[0164] The term "acyloxy" is art-recognized and refers to a group represented by the general formula hydrocarbyl C(O)O-, preferably alkyl C(O)O-.

[0165] The term "alkoxy" refers to an alkyl group bonded to an oxygen atom. In some embodiments, the alkoxy group has 1 to 20 carbon atoms. Representative alkoxy groups include methoxy, trifluoromethoxy, ethoxy, propoxy, and tert-butoxy.

[0166] The term "alkoxyalkyl" refers to an alkyl group substituted with an alkoxy group and can be represented by the general formula alkyl-O-alkyl.

[0167] The term "alkenyl" as used in this specification refers to an aliphatic group containing at least one double bond, and includes "unsubstituted alkenyl" and "substituted alkenyl", wherein the latter refers to an alkenyl moiety having a substituent replacing a hydrogen atom on one or more carbon atoms of the alkenyl. Typically, unless otherwise defined, a straight-chain or branched alkenyl has 1 to about 20 carbon atoms, preferably 1 to about 10 carbon atoms. Such substituents may be present on one or more carbon atoms that are included or not included in one or more double bonds. In addition, such substituents include all substituents that are considered to be alkyl groups as described below, as long as they do not impair stability. For example, it is contemplated that an alkenyl group may be substituted by one or more alkyl, carbocyclic, aryl, heterocyclic or heteroaryl groups.

[0168] "Alkyl" or "alkane" is a fully saturated straight-chain or branched non-aromatic hydrocarbon. Typically, unless otherwise defined, a straight-chain or branched alkyl group has 1 to about 20 carbon atoms, preferably 1 to about 12 carbon atoms. In some embodiments, the alkyl group has 1 to 8 carbon atoms, 1 to 6 carbon atoms, 1 to 4 carbon atoms, or 1 to 3 carbon atoms. Examples of straight-chain and branched alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, amyl, and octyl.

[0169] In addition, the term "alkyl" used in the specification, examples and claims includes "unsubstituted alkyl" and "substituted alkyl", wherein the latter refers to an alkyl moiety having a substituent replacing one or more hydrogen atoms on the substitutable carbon atom of the hydrocarbon backbone. As such substituents, unless otherwise specified, for example, halogen (e.g., fluorine), hydroxyl, carbonyl (e.g., carboxyl, alkoxycarbonyl, formyl or acyl), thiocarbonyl (e.g., thioester, thioacetate or thioformate), alkoxy, phosphoryl, phosphate, phosphonate, phosphinate, amino, amide, amidine, imine, cyano, nitro, azido, sulfhydryl, alkylthio, sulfate, sulfonate, sulfamoyl, sulfonamide, sulfonyl, heterocyclic, aralkyl or aromatic or heterocyclic aromatic moieties can be cited. In a preferred embodiment, the substituents on the substituted alkyl group are selected from C 1-6 Alkyl, C 3-6Cycloalkyl, halogen, carbonyl, cyano or hydroxyl. In a more preferred embodiment, the substituent on the substituted alkyl is selected from fluorine, carbonyl, cyano or hydroxyl. It will be understood by those skilled in the art that, when appropriate, the portion substituted on the hydrocarbon chain itself may be substituted. For example, as substituents for the substituted alkyl, substituted and unsubstituted amino, azido, imino, amide, phosphoryl (including phosphonates and phosphites), sulfonyl (including sulfates, sulfonamides, sulfamoyl and sulfonates) and silanyl can be cited, as well as ethers, alkylthio, carboxyl (including ketones, aldehydes, carboxylates and esters), -CF3, -CN, etc. Exemplary substituted alkyls are described below. The cycloalkyl may be further substituted by alkyl, alkenyl, alkoxy, alkylthio, aminoalkyl, alkyl substituted with carbonyl, -CF3, -CN, etc.

[0170] When used in conjunction with a chemical moiety (e.g., acyl, acyloxy, alkyl, alkenyl, alkynyl, or alkoxy), the term "C x-y " refers to a group containing x to y carbon atoms in the chain. For example, the term "C x-y "Alkyl" refers to a substituted or unsubstituted saturated hydrocarbon group (including straight-chain alkyl and branched-chain alkyl) containing x to y carbon atoms in the chain, including haloalkyl. Preferred haloalkyl groups include trifluoromethyl, difluoromethyl, 2,2,2-trifluoroethyl and pentafluoroethyl. C0 alkyl indicates a hydrogen atom when the group is in the terminal position and a bond when it is internal. The term "C 2-y Alkenyl" and "C 2-y "Alkynyl" refers to a substituted or unsubstituted unsaturated aliphatic group analogous in length and substitution potential to the alkyls described above, but containing at least one double or triple bond, respectively.

[0171] The term "alkylamino" used in the present specification refers to an amino group substituted by at least one alkyl group.

[0172] The term "alkylthio group" used in the present specification refers to a thiol group substituted with an alkyl group, and can be represented by the general formula alkylS-.

[0173] The term "arylthio group" used in the present specification refers to a thiol group substituted with an alkyl group, and can be represented by the general formula arylS-.

[0174] The term "alkynyl" as used in this specification refers to an aliphatic group containing at least one triple bond, and includes "unsubstituted alkynyl" and "substituted alkynyl", wherein the latter refers to an alkynyl moiety having a substituent replacing a hydrogen on one or more carbon atoms of the alkynyl group. Typically, unless otherwise defined, a straight-chain or branched alkynyl group has 1 to about 20 carbon atoms, preferably 1 to about 10 carbon atoms. Such substituents may be present on one or more carbon atoms that are included or not included in one or more triple bonds. In addition, such substituents include all substituents that are considered to be alkyl groups as described below, as long as they do not impair stability. For example, it is contemplated that an alkynyl group may be substituted by one or more alkyl, carbocyclyl, aryl, heterocyclyl, or heteroaryl groups.

[0175] The term "amide" as used in this specification refers to the following groups,

[0176] [Chemical Formula 7]

[0177]

[0178] Where R A Each independently represents hydrogen or a hydrocarbon group, or two R A Together with the nitrogen atom to which it is bonded, it forms a heterocyclic ring having 4 to 8 atoms in the ring structure.

[0179] The terms "amine" and "amino" are art-recognized and refer to unsubstituted and substituted amines and salts thereof, such as the moiety that can be represented by,

[0180] [Chemical Formula 8]

[0181] or

[0182] Where R A Each independently represents hydrogen or a hydrocarbon group, or two R A Together with the nitrogen atom to which it is bonded, it forms a ring structure. A heterocyclic ring having 4 to 8 atoms in the ring structure.

[0183] The term "aminoalkyl group" used in the present specification refers to an alkyl group substituted by an amino group.

[0184] The term "aralkyl group" used in the present specification refers to an alkyl group substituted by an aryl group.

[0185] As used herein, the term "aryl" includes substituted or unsubstituted monocyclic aromatic groups in which each ring atom is a carbon atom. Preferably, the ring is a 6-membered or 20-membered ring, more preferably a 6-membered ring. Preferably, the aryl group has 6 to 10 carbon atoms, more preferably 6 to 25 carbon atoms.

[0186] The term "aryl" also includes polycyclic rings having two or more rings, wherein two or more carbon atoms are shared by two adjacent rings, wherein at least one ring is an aromatic ring, for example, the other rings can be cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl and / or heterocyclyl. Aryl includes benzene, naphthalene, phenanthrene, phenol, aniline, etc.

[0187] The term "carbamate" is art-recognized and refers to the group

[0188] [Chemical Formula 9]

[0189] or

[0190] Where R A Each independently represents hydrogen or a hydrocarbon group (eg, an alkyl group), or two R A Together with the shared intervening atoms, they form a heterocyclic ring having 4 to 8 atoms in the ring structure.

[0191] As used herein, the terms "carbocycle" and "carbocyclic" refer to saturated or unsaturated rings in which all atoms of the ring are carbon atoms. Preferably, the carbocyclic group has 3 to 20 carbon atoms. The term carbocycle includes both aromatic carbocycles and non-aromatic carbocycles. Non-aromatic carbocycles include both cycloalkane rings in which all carbon atoms are saturated and cycloalkene rings containing at least one double bond. "Carbocycle" includes 5-7 membered monocyclic rings and 8-12 membered bicyclic rings. Each ring of a bicyclic carbocycle can 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 ring shares two adjacent atoms with another ring. Each ring of a fused carbocycle can be selected from saturated, unsaturated, and aromatic rings. In one exemplary embodiment, an aromatic ring (e.g., phenyl (Ph)) can be fused to a saturated or unsaturated ring (e.g., cyclohexane, cyclopentane, or cyclohexene). Any combination of saturated, unsaturated, and aromatic bicyclic rings, where valence permits, is included in the definition of carbocycle. Exemplary "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. Exemplary fused carbocycles include decahydronaphthalene, 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 capable of retaining a hydrogen atom.

[0192] "Cycloalkyl" is a fully saturated cyclic hydrocarbon. "Cycloalkyl" includes monocyclic and bicyclic rings. Preferably, the cycloalkyl group has 3 to 20 carbon atoms. Typically, unless otherwise specified, a monocyclic cycloalkyl group has 3 to about 10 carbon atoms, more typically 3 to 8 carbon atoms. The second ring of a bicyclic cycloalkyl group can be selected from saturated, unsaturated, and aromatic rings. Cycloalkyl groups include bicyclic molecules in which one, two, or more than three atoms are shared between the two rings. The term "fused cycloalkyl" refers to a bicyclic cycloalkyl group in which each ring shares two adjacent atoms with another ring. The second ring of a fused bicyclic cycloalkyl group can be selected from saturated, unsaturated, and aromatic rings. "Cycloalkenyl" is a cyclic hydrocarbon group containing one or more double bonds.

[0193] The term "carbocyclylalkyl" used in the present specification refers to an alkyl group substituted with a carbocyclyl group.

[0194] The term "carbonate" as used in this specification refers to the group -OCO2-R A , where R A Represents a hydrocarbon group.

[0195] The term "carboxyl group" used in the present specification refers to a group represented by the formula -CO2H.

[0196] The term "ester" as used in this specification refers to the group -C(O)OR A , where R A Represents a hydrocarbon group.

[0197] As used herein, the term "ether" refers to a group consisting of a hydrocarbon group attached to another hydrocarbon group via an oxygen atom. Thus, an ether substituent of a hydrocarbon group may be hydrocarbon-O-. Ethers may 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 may be represented by the general formula alkyl-O-alkyl.

[0198] The terms "halo" and "halogen" as used in this specification refer to halogen atoms including chlorine, fluorine, bromine and iodine.

[0199] The term "heteroaralkyl" used in the present specification refers to an alkyl group substituted by a heteroaryl group.

[0200] The term "heteroalkyl" as used in this specification refers to a saturated or unsaturated chain of carbon atoms and at least one heteroatom, wherein no two heteroatoms are adjacent.

[0201] The term "heteroaryl" includes substituted or unsubstituted aromatic monocyclic ring structures, preferably 5-20 membered rings, more preferably 5-6 membered rings, whose ring structure includes at least one heteroatom, preferably 1-4 heteroatoms, more preferably 1 or 2 heteroatoms. Preferably, the heteroaryl group has 2-40 carbon atoms, more preferably 2-25 carbon atoms. The term "heteroaryl" also includes polycyclic ring systems having two or more rings, wherein two or more carbon atoms are shared by two adjacent rings, and at least one ring is a heteroaromatic ring. For example, the other rings can be cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, and / or heterocyclyl. Heteroaryl groups include, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrazine, pyridazine, pyrimidine, and carbazole.

[0202] The term "aryloxy" refers to an aryl group bonded to an oxygen atom. Preferably, the aryloxy group has 6 to 40 carbon atoms, more preferably 6 to 25 carbon atoms.

[0203] The term "heteroaryloxy" refers to an aryl group bonded to an oxygen atom. Preferably, the heteroaryloxy group has 3 to 40 carbon atoms, more preferably 3 to 25 carbon atoms.

[0204] The term "heteroatom" used in this specification refers to an atom of any element other than a carbon atom or a hydrogen atom. Preferred heteroatoms are nitrogen, oxygen and sulfur.

[0205] The terms "heterocyclyl," "heterocycle," and "heterocyclic" refer to substituted or unsubstituted non-aromatic ring structures, preferably 3-20-membered rings, more preferably 3-7-membered rings, whose ring structures include at least one heteroatom, preferably 1-4 heteroatoms, more preferably 1 or 2 heteroatoms. The terms "heterocyclyl" and "heterocycle" also include polycyclic ring systems having two or more rings, wherein two or more carbon atoms are shared by two adjacent rings, and wherein at least one ring is a heterocycle, for example, the other rings can be cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, and / or heterocyclyl. Heterocyclyl groups include, for example, piperidine, piperazine, pyrrolidine, morpholine, lactones, lactams, and the like.

[0206] The term "heterocyclylalkyl" used in the present specification refers to an alkyl group substituted by a heterocyclyl group.

[0207] As used herein, the term "hydrocarbyl" refers to a group bonded via a carbon atom, wherein the carbon atom does not have a ═O or ═S substituent. A hydrocarbyl group may optionally include heteroatoms. Examples of hydrocarbyl groups include, but are not limited to, alkyl, alkenyl, alkynyl, alkoxyalkyl, aminoalkyl, aralkyl, aryl, aralkyl, carbocyclyl, cycloalkyl, carbocyclylalkyl, heteroaralkyl, heteroaryl bonded via a carbon atom, heterocyclyl bonded via a carbon atom, heterocycloalkyl, or hydroxyalkyl. In other words, groups such as methyl, ethoxyethyl, 2-pyridyl, or trifluoromethyl are hydrocarbyl groups, but substituents such as acetyl (which has a ═O substituent on the carbon atom to which it is bonded) and ethoxy (which is attached via an oxygen atom rather than a carbon atom) are not hydrocarbyl groups.

[0208] The term "hydroxyalkyl" used in the present specification refers to an alkyl group substituted with a hydroxy group.

[0209] When used in conjunction with a chemical moiety such as acyl, acyloxy, alkyl, alkenyl, alkynyl, or alkoxy, the term "lower" refers to groups that include the presence of 6 or fewer non-hydrogen atoms in the substituent. For example, "lower alkyl" refers to an alkyl group containing 6 or fewer carbon atoms. In some embodiments, the alkyl group has 1 to 6 carbon atoms, 1 to 4 carbon atoms, or 1 to 3 carbon atoms. In specific embodiments, the acyl, acyloxy, alkyl, alkenyl, alkynyl, or alkoxy substituents defined in the present invention are lower acyl, lower acyloxy, lower alkyl, lower alkenyl, lower alkynyl, or lower alkoxy, respectively, when present alone or in combination with other substituents (e.g., hydroxyalkyl and aralkyl).

[0210] The terms "polycyclic," "polycycle," and "polycyclic" refer to two or more rings (e.g., cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, and / or heterocyclyl) in which two or more atoms are common to two adjacent rings, e.g., the rings are "fused rings." Each ring present in the polycycle can be substituted or unsubstituted. In certain embodiments, each ring present in the polycycle contains 3 to 10 atoms, preferably 5 to 7 atoms, in the ring.

[0211] In the term "poly(meta-phenylene oxides)", the term "phenylene" refers inclusively to a 6-membered aryl or 6-membered heteroaryl moiety. Exemplary poly(meta-phenylene oxides) are described as the first to 20th embodiments of the present invention.

[0212] The term "silyl" refers to a silicon moiety having three hydrocarbyl moieties attached thereto.

[0213] The term "substituted" refers to a moiety having a substituent that replaces a hydrogen on one or more carbon atoms in the main chain. It should be understood that "substituted" or "substituted by" includes the following implicit restrictions: such substitution is consistent with the valence state of the substituted atom and the substituent, and the compound is stable due to the substitution (for example, it does not spontaneously undergo changes such as transfer, cyclization, elimination, etc.). The moiety that can be substituted may include any suitable substituent described in this specification, for example, acyl, amide, acyloxy, alkoxy, alkoxyalkyl, alkenyl, alkyl, alkylamino, alkylthio, arylthio, alkynyl, amide, amino, aminoalkyl, aralkyl, carbamate, carbocyclyl, cycloalkyl, carbocyclylalkyl, carbonate, ester, ether, heteroaralkyl, heterocyclyl, heterocyclylalkyl, hydrocarbon, silanyl, sulfone or thioether. The term "substituted" as used in this specification includes all permissible substituents of organic compounds. In a broad sense, permissible substituents include acyclic and cyclic, branched and unbranched, carbocyclic and heterocyclic, aromatic and non-aromatic substituents of organic compounds. For appropriate organic compounds, permissible substituents may be more than one and may be the same or different. For the purposes of the present invention, heteroatoms such as nitrogen may have hydrogen substituents and / or any permissible substituents of the organic compounds described in this specification that satisfy the heteroatom valence state. Substituents may include any substituent described in this specification, for example, halogen, hydroxyl, carbonyl (e.g., carboxyl, alkoxycarbonyl, formyl or acyl), thiocarbonyl (e.g., thioester, thioacetate or thioformate), alkoxy, phosphoryl, phosphate, phosphonate, phosphinate, amino, amide, amidine, imine, cyano, nitro, azido, sulfhydryl, alkylthio, sulfate, sulfonate, sulfamoyl, sulfonamido, sulfonyl, heterocyclic, aralkyl or aromatic or heteroaromatic moieties. In a preferred embodiment, the substituents on the substituted alkyl group are selected from C 1-6 Alkyl, C 3-6 Cycloalkyl, halogen, carbonyl, cyano or hydroxy. In a more preferred embodiment, the substituent on the substituted alkyl is selected from fluorine, carbonyl, cyano or hydroxy. It will be understood by those skilled in the art that the substituent itself may be substituted when appropriate. Unless specifically stated as "unsubstituted", references to chemical groups in this specification should be understood to include substituted variants. For example, reference to an "aryl" group or moiety implicitly includes both substituted and unsubstituted variants.

[0214] The term "sulfonate" is art-recognized and refers to the group SO3H or a pharmaceutically acceptable salt thereof.

[0215] The term "sulfone" is art-recognized and refers to the group -S(O)2-R A , where R A Represents a hydrocarbon group.

[0216] The term "thioether" as used in this specification is equivalent to an ether in which oxygen is replaced by sulfur.

[0217] The term "symmetrical molecule" as used in this specification refers to a molecule with group symmetry or synthetic symmetry. The term "group symmetry" as used in this specification refers to a molecule having symmetry consistent with the group theory of molecular symmetry. The term "synthetic symmetry" as used in this specification refers to a molecule selected so that a regioselective synthesis strategy is not required.

[0218] The term "donor" used herein refers to a molecular fragment that can be used in an organic light-emitting diode and has the property of donating electrons from its highest occupied molecular orbital to an acceptor by excitation. In an exemplary embodiment, the ionization potential of the donor is -6.5 eV or higher.

[0219] The term "acceptor" used herein refers to a molecular fragment that can be used in an organic light-emitting diode and has the property of accepting electrons from an excited donor into its lowest unoccupied molecular orbital. In an exemplary embodiment, the electron affinity of the acceptor is -0.5 eV or less.

[0220] As used herein, the term "bridge" refers to a molecular fragment that can be included in a molecule and that covalently links the acceptor and donor moieties. The bridge can, for example, be further conjugated to the acceptor moiety, the donor moiety, or both. While not being bound by any particular theory, it is believed that the bridge moiety can spatially confine the acceptor and donor moieties to a specific structure, thereby preventing the formation of a π-conjugated system of the donor and acceptor moieties. Examples of suitable bridge moieties include phenyl, vinyl, and ethynyl.

[0221] The term "multivalent" as used in this specification means that a molecular fragment is bonded to at least two other molecular fragments. For example, a bridge moiety is multivalent.

[0222] “~~~” or “*” used in this specification refers to a bonding site between two atoms.

[0223] "Hole transport layer (HTL)" and similar terms refer to a layer made of a material that transports holes. It is recommended to have a high hole mobility. The HTL is used to help block the passage of electrons transported by the emissive layer. Low electron affinity is generally required to block electrons. The HTL should desirably have a large triplet state to block the migration of excitons 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).

[0224] "Light-emitting layer" and similar terms refer to a layer that emits light. In some embodiments, the light-emitting layer is composed of a host material and a guest material. The guest material is also called a dopant material, but the present invention is not limited thereto. The host material can be bipolar or monopolar and can be used alone or by combining two or more host materials. The optoelectronic properties of the host material can be different depending on the type of guest material used (TADF, phosphorescence or fluorescence). For fluorescent guest materials, the host material should have a good spectral overlap between the adsorption of the guest material and the emission of the host to induce a good Förster transfer to the guest material. For phosphorescent guest materials, the host material should have a high triplet energy to constrain the triplet state of the guest material. For TADF guest materials, the host material should have both a spectral overlap and a high triplet energy.

[0225] "Dopant" and similar terms refer to additives used in carrier transport layers, light-emitting layers or other layers. "Dopant" and similar terms refer to electron acceptors or donors that increase the conductivity of the organic layer of an organic electronic device when added as an additive to the organic layer. Organic semiconductors may also be affected by doping in terms of their conductivity. Such organic semiconductor matrix materials can be made of compounds with electron-donating properties or compounds with electron-withdrawing properties. In the light-emitting layer, dopants and similar terms refer to, for example, light-emitting materials dispersed in a matrix called a host. When a triplet recovery material is doped into the light-emitting layer or included in an adjacent layer to improve the efficiency of exciton generation, it is called an auxiliary dopant. Auxiliary dopants can, on the contrary, shorten the life of excitons. There is no particular restriction on the content of the auxiliary dopant in the light-emitting layer or the adjacent layer as long as the triplet recovery material improves the efficiency of exciton generation. The content of the auxiliary dopant in the light-emitting layer is preferably more than the light-emitting material, more preferably at least twice the amount of the light-emitting material. In the light-emitting layer, the content of the main material is preferably 50% by weight or more, the content of the auxiliary dopant is preferably 5% by weight or more and 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 or more and less than 10% by weight. The content of the auxiliary dopant in the adjacent layer can be 50% by weight or more, or 100% by weight. When a device comprising a triplet recovery material in the light-emitting layer or an adjacent layer has a higher luminous efficiency than a device not comprising a triplet recovery material, such triplet recovery material functions as an auxiliary dopant. The light-emitting layer comprising a main material, an auxiliary dopant and a light-emitting material satisfies the following (A), preferably satisfies the following (B).

[0226] ES1(A)>ES1(B)>ES1(C) (A)

[0227] ET1(A)>ET1(B) (B)

[0228] Wherein, ES1(A) represents the lowest excited singlet energy level of the host material, ES1(B) represents the lowest excited singlet energy level of the auxiliary dopant, ES1(C) represents the lowest excited singlet energy level of the luminescent material, ET1(A) represents the lowest excited triplet energy level of the host material at 77 K, and ET1(B) represents the lowest excited triplet energy level of the auxiliary dopant at 77 K. The auxiliary dopant preferably has an energy difference ΔE between the lowest singlet excited state and the lowest triplet excited state at 77 K of 0.3 eV or less, more preferably 0.2 eV or less, and further preferably has an energy difference ΔE between the lowest singlet excited state and the lowest triplet excited state of 0.1 eV or less. ST .

[0229] In the compounds of the present invention, any atom not designated as a specific isotope is included as any stable isotope of that atom. Unless otherwise stated, when a state is designated as "H" or "hydrogen", the state is understood to be hydrogen with a natural isotopic composition. And, unless otherwise stated, when a state is specifically designated as "D" or "deuterium", the state is understood to be a state with an abundance of deuterium of at least 3340 times the natural abundance of deuterium (which is 0.015%) (i.e., a deuterium content of at least 50.1%).

[0230] The term "isotope enrichment ratio" used in this specification refers to the ratio of the amount of an isotope to the amount of a specific isotope in nature.

[0231] In various embodiments, the compounds of the invention have an isotopic enrichment (per deuterium atom content) of at least 3500 (52.5% deuterium 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).

[0232] The term "isotopic substitute" refers to a species that differs from a particular compound of the present invention only in its isotopic composition.

[0233] When referring to the compounds of the present invention, the term "compound" refers to a collection of molecules with the same chemical structure, but there may be isotopic variations among the constituent atoms of the molecule. Therefore, it will be clear to those skilled in the art that a compound represented by a specific chemical structure containing a specified deuterium atom will also contain a smaller amount of isotopic substitutes with hydrogen atoms at one or more specified deuterium positions in the structure. The relative amount of such isotopic substitutes in the compounds of the present invention will depend on a variety of factors, including the isotopic purity of the deuterated reagent used to prepare the compound and the deuterium incorporation efficiency in the various synthesis steps used to prepare the compound. However, as described above, the relative amount of all such isotopic substitutes will be less than 49.9% of the compound. In another embodiment, the relative amount of all such isotopic substitutes 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.

[0234] "Substituted with deuterium" means replacing one or more hydrogen atoms with the corresponding number of deuterium atoms. "D" and "d" both refer to deuterium.

[0235] (Principle of OLED)

[0236] OLEDs are typically composed of a layer of organic material or compound between two electrodes (anode and cathode). Organic molecules conduct electricity due to the delocalization of π electrons caused by partial or complete molecular conjugation. When voltage is applied, electrons from the highest occupied molecular orbital (HOMO) present in the anode flow into the lowest unoccupied molecular orbital (LUMO) of the organic molecule present in the cathode. Removing electrons from the HOMO is also called inserting electron holes into the HOMO. Electrostatic forces bring electrons and holes toward each other, recombining and forming excitons (bound states of electrons and holes). As the excited state decays and the electron energy levels relax, radiation with a frequency in the visible spectrum is emitted. The frequency of this radiation depends on the material's band gap, that is, the energy difference between the HOMO and LUMO.

[0237] When the electron and hole are fermions with half-integer spins, the exciton can assume either a singlet or triplet state, depending on how the electron and hole spins are combined. Statistically, three triplet excitons are formed for each singlet exciton. Decay from the triplet state is spin-forbidden, which increases the timescale for transitions and limits the internal efficiency of fluorescent devices. Phosphorescent organic light-emitting diodes utilize spin-orbit interactions to facilitate intersystem crossing between singlet and triplet states, thereby emitting light from both singlet and triplet states and improving internal efficiency.

[0238] One prototypical phosphorescent material is tris(2-phenylpyridine)iridium (Ir(ppy)3), in which the excited state is charge-transferred from the Ir atom to an organic ligand. This approach has reduced the triplet lifetime to a fraction of a second, orders of magnitude slower than the radiative lifetime achieved by fully allowed transfer, such as fluorescence. Ir-based phosphors have proven acceptable for many display applications, but losses due to the high triplet density still prevent OLEDs from being used in higher-brightness solid-state lighting.

[0239] Thermally activated delayed fluorescence (TADF) minimizes the energy difference (ΔE) between the singlet and triplet states. ST The exchange splitting decreases from typical values ​​of 0.4–0.7 eV to thermal energies (proportional to kBT, where kB is the Boltzmann constant and T is the temperature). The step gap means, for example, that even if the coupling between the states is small, thermal agitation can still cause a population of particles to transfer between singlet and triplet energy levels on relevant timescales.

[0240] TADF molecules consist of donor and acceptor moieties that are directly connected by a covalent bond or via a conjugated linker (or "bridge"). The "donor" moiety is likely to transfer electrons from its HOMO to the "acceptor" moiety upon excitation. The "acceptor" moiety is likely to accept electrons from the "donor" moiety into its LUMO. The donor-acceptor nature of the TADF molecule results in a molecule that exhibits extremely low ΔE ST Because thermal molecular motion can cause random variations in the optical properties of donor-acceptor systems, a rigid three-dimensional arrangement of the donor and acceptor moieties can be used to confine the nonradiative decay of the charge-transfer state via internal conversion during the lifetime of the excitation.

[0241] Therefore, it is beneficial to develop methods that reduce ΔE ST The researchers also developed systems with high reverse intersystem crossing (RISC) of triplet excitons. Such systems are believed to result in increased quantum efficiency and reduced emission lifetime. Systems with these characteristics are able to emit light without experiencing the rapid degradation common in currently known OLEDs.

[0242] In some embodiments of the present invention, the luminescent material of the present invention can emit light in the UV region, blue, green, yellow, orange, red region (for example, about 420 nm to about 500 nm, about 500 nm to about 600 nm, or about 600 nm to about 700 nm) or near infrared region when excited by thermal or electronic means.

[0243] In some embodiments of the present invention, the luminescent material of the present invention can emit light in the red or orange region of the visible spectrum (eg, about 620 nm to about 780 nm, about 650 nm) when excited by thermal or electronic means.

[0244] In some embodiments of the present invention, the luminescent material of the present invention can emit light in the orange or yellow region of the visible spectrum (eg, about 570 nm to about 620 nm, about 590 nm, about 570 nm) when excited by thermal or electronic means.

[0245] In some embodiments of the present invention, the luminescent material of the present invention can emit light in the green region of the visible spectrum (eg, about 490 nm to about 575 nm, about 510 nm) when excited by thermal or electronic means.

[0246] In some embodiments of the present invention, the luminescent material of the present invention can emit light in the blue region of the visible spectrum (eg, about 400 nm to about 490 nm, about 475 nm) when excited by thermal or electronic means.

[0247] In some embodiments of the present invention, the luminescent materials of the present invention can emit light in the ultraviolet spectral region (eg, 280-400 nm) when excited by thermal or electronic means.

[0248] In some embodiments of the present invention, the luminescent materials of the present invention can emit light in the infrared spectral region (eg, 780 nm to 2 μm) when excited by thermal or electronic means.

[0249] (Selection of Compounds)

[0250] The electronic properties of libraries of small molecule chemicals can be calculated using known ab initio quantum chemical calculations. For example, by solving the Hartree-Fock equation (TD-DFT / B3LYP / 6-31G*) using time-dependent density functional theory (using 6-31G* as the basis set and employing Becke triple parameters and the Lee-Yang-Parr hybrid functional), molecular fragments (fractions) can be screened for molecules with HOMOs above a specific threshold and LUMOs below a specific threshold, with calculated triplet values ​​exceeding 2.75 eV.

[0251] Thus, for example, when a HOMO energy (e.g., ionization potential) of -6.5 eV or higher is present, a donor moiety ("D") can be selected. Furthermore, when a LUMO energy (e.g., electron affinity) of -0.5 eV or lower is present, an acceptor moiety ("A") can be selected. The bridge moiety ("B") can spatially constrain the acceptor and donor moieties to a specific, rigid conjugated system, thereby preventing overlap between the conjugated π systems of the donor and acceptor moieties.

[0252] In some embodiments, a compound library is filtered using one or more of the following properties:

[0253] 1. Emitting light near a specific wavelength

[0254] 2. Calculated triplet values ​​above a specific energy level

[0255] 3. ΔE below a certain value ST value

[0256] 4. Quantum yield above a certain value

[0257] 5.HOMO energy level

[0258] 6.LUMO energy level

[0259] In some embodiments, the difference between the lowest singlet excited state and the lowest triplet excited state (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.

[0260] In some embodiments, the light-emitting materials of the present invention exhibit a quantum yield greater than 25%, for example, 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.

[0261] (Film Formation)

[0262] In some embodiments, a film comprising the luminescent material of the present invention can be formed by a wet process. In the wet process, a solution in which the luminescent material of the present invention is dissolved is applied to a surface, and a film is formed after removing the solvent. As wet processes, spin coating, slit coating, inkjet (spraying), gravure printing, offset printing, and flexographic printing can be cited, but are not limited thereto. In the wet process, a suitable organic solvent capable of dissolving the luminescent material of the present invention is selected and used. For example, non-polar solvents such as aromatic hydrocarbon solvents comprising toluene can be used, but the solvents that can be used are not limited thereto. In some embodiments, a substituent (e.g., an alkyl group) for improving the solubility in an organic solvent can be introduced into the compound contained in the luminescent material.

[0263] In some embodiments, a film comprising the luminescent material of the present invention can be formed by a dry process. In some embodiments, as a dry process, a vacuum vapor deposition method can be used, but is not limited thereto. When the vacuum vapor deposition method is used, the compounds constituting the film can be vapor-co-deposited by individual vapor deposition sources, or can be vapor-co-deposited by a single vapor deposition source in which the compounds are mixed. When a single vapor deposition source is used, a mixed powder formed by mixing powders of the compound can be used, a compressed molded body formed by compressing the mixed powder can be used, or a mixture formed by heating, melting and cooling the compounds can be used. In some embodiments, the vapor deposition rates (weight loss rates) of the various compounds contained in a single vapor deposition source are inconsistent. By performing vapor co-deposition under almost identical conditions, a film having a composition ratio corresponding to the composition ratio of the various compounds contained in the vapor deposition source can be formed. If a plurality of compounds are mixed as a vapor deposition source in a composition ratio identical to the composition ratio of the film to be formed, a film having the desired composition ratio can be simply formed. In some embodiments, the temperature at which the weight reduction rate of each compound to be vapor-phase co-deposited is the same can be determined, and this temperature can be adopted as the temperature during vapor-phase co-deposition.

[0264] [Use Examples of the Light-Emitting Material of the Present Invention]

[0265] (Organic Light Emitting Diode)

[0266] One embodiment of the present invention relates to the use of a luminescent material of the present invention as a luminescent material for an organic light-emitting device. In some embodiments, the luminescent material of the present invention can be effectively used as a luminescent material in a luminescent layer of an organic light-emitting device. In some embodiments, the luminescent material of the present invention comprises a delayed fluorescence (delayed phosphor) that emits delayed fluorescence. In some embodiments, the present invention provides a delayed phosphor comprising the luminescent material of the present invention. In some embodiments, the present invention relates to the use of a luminescent material of the present invention as a delayed phosphor. In some embodiments, the present invention relates to a method for generating delayed fluorescence from the luminescent material of the present invention. In some embodiments, an organic light-emitting device comprising the luminescent material of the present invention as a luminescent material emits delayed fluorescence and shows high luminous efficiency.

[0267] In some embodiments, the donor compound, acceptor compound, and luminescent compound are oriented parallel to the substrate, comprising the luminescent material of the present invention. In some embodiments, the substrate is a film-forming surface. In some embodiments, the orientation of the donor compound, acceptor compound, and luminescent compound relative to the film-forming surface influences or determines the propagation direction of light emitted by the arranged compounds. In some embodiments, by aligning the propagation direction of light emitted by the donor compound, acceptor compound, and luminescent compound, light extraction efficiency from the luminescent layer is improved.

[0268] One embodiment of the present invention relates to an organic light-emitting device. In some embodiments, the organic light-emitting device includes a light-emitting layer. In some embodiments, the light-emitting layer includes a light-emitting material of the present invention as a light-emitting material. In some embodiments, the organic light-emitting device is an organic photoluminescent device (organic PL device). In some embodiments, the organic light-emitting device is an organic electroluminescent device (organic EL device). In some embodiments, the exciplex formed by the donor compound and the acceptor compound assists the emission of other light-emitting materials included in the light-emitting layer (as a so-called auxiliary dopant). In some embodiments, the exciplex formed by the donor compound and the acceptor compound included in the light-emitting layer is in its lowest excited singlet energy level, including between the lowest excited singlet energy level of the host material included in the light-emitting layer and the lowest excited singlet energy level of the other light-emitting material included in the light-emitting layer.

[0269] In some embodiments, the organic photoluminescent device comprises at least one light-emitting layer. In some embodiments, the organic electroluminescent device comprises at least one anode, a cathode, and an organic layer between the anode and the cathode. In some embodiments, the organic layer comprises at least a light-emitting layer. In some embodiments, the organic layer comprises only a light-emitting layer. In some embodiments, the organic layer comprises one or more organic layers other than the light-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 having a hole injection function, and the electron transport layer may be an electron injection transport layer having an electron injection function. Examples of organic electroluminescent devices are shown in Figure 1 middle.

[0270] (Substrate)

[0271] In some embodiments, the organic electroluminescent device of the present invention is supported by a substrate. The substrate is not particularly limited and may be made of any material commonly used in organic electroluminescent devices, such as glass, transparent plastic, quartz, and silicon.

[0272] (anode)

[0273] 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 large work function (above 4 eV). 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 manufactured by vapor deposition or sputtering. In some embodiments, the film is patterned by photolithography. In some embodiments where the pattern does not require high precision (e.g., about 100 μm or more), the pattern can be formed using a mask of the desired shape during vapor deposition or sputtering of 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 and a coating method is used. In some embodiments, when the emitted light passes through the anode, the transmittance of the anode exceeds 10%, and the sheet resistance of the anode is below several hundred ohms per square. In some embodiments, the thickness of the anode is 10 to 1,000 nm. In some embodiments, the thickness of the anode is 10 to 200 nm. In some embodiments, the thickness of the anode varies depending on the material used.

[0274] (cathode)

[0275] In some embodiments, the cathode is made of a metal (called an electron injection metal) whose electrode material has a relatively small work function (less than 4 eV), 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 metals. In some embodiments, a mixture of an electron injection metal and a second metal is used, and the second metal is a stable metal with a work function greater than that of the electron injection metal. 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 electron injection characteristics and oxidation resistance. In some embodiments, the cathode is manufactured by forming the electrode material into a thin film by vapor deposition or sputtering. In some embodiments, the film resistance of the cathode is less than several hundred ohms per square. In some embodiments, the thickness of the cathode is in the range of 10 nm to 5 μm. In some embodiments, the thickness of the cathode is in the range of 50 to 200 nm. In some embodiments, either the anode or cathode of the organic electroluminescent device is transparent or translucent in order to transmit the emitted light. In some embodiments, the transparent or translucent electroluminescent device improves the emission brightness.

[0276] In some embodiments, a transparent or translucent cathode is formed by forming the cathode from a conductive transparent material as described with respect to the anode. In some embodiments, a device comprises an anode and a cathode that are both transparent or translucent.

[0277] (Luminescent layer)

[0278] 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. In some embodiments, the layer emits light.

[0279] In some embodiments, only the luminescent material is used as the luminescent layer. In some embodiments, the luminescent layer comprises a luminescent material and a host material. In some embodiments, the luminescent material is an exciplex or luminescent compound formed by a donor compound and an acceptor compound. In some embodiments, singlet excitons and triplet excitons generated in the luminescent material are confined within the luminescent material to improve the luminescence efficiency of the organic electroluminescent device or organic photoluminescent device. In some embodiments, a host material is used in addition to the luminescent material in the luminescent 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 that of the luminescent material of the present invention. In some embodiments, the singlet excitons and triplet excitons generated in the luminescent material of the present invention are confined within the molecules of the luminescent material of the present invention. In some embodiments, the singlet and triplet excitons are sufficiently confined to improve luminescence efficiency. In some embodiments, host materials that achieve high luminescence efficiency without sufficient confinement of singlet and triplet excitons can be used in the present invention without particular limitation, although high luminescence efficiency can still be achieved. In some embodiments, luminescence is generated in the luminescent material in the luminescent 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 the emitted light from the host material. In some embodiments, the emitted light consists of the emitted light from the host material. In some embodiments, the emitted light includes the emitted light from the exciplex formed by the donor compound and the acceptor compound and the luminescent compound, and the emitted light from the host material. In some embodiments, TADF molecules and host materials are used. In some embodiments, TADF is an auxiliary dopant.

[0280] In some embodiments, when a host material is used, the amount of the exciplex and the luminescent compound contained in the light-emitting layer is greater than 0.1% by weight. In some embodiments, when a host material is used, the amount of the exciplex and the luminescent compound contained in the light-emitting layer is greater than 1% by weight. In some embodiments, when a host material is used, the amount of the exciplex and the luminescent compound contained in the light-emitting layer is less than 50% by weight. In some embodiments, when a host material is used, the amount of the exciplex and the luminescent compound contained in the light-emitting layer is less than 20% by weight. In some embodiments, when a host material is used, the amount of the exciplex and the luminescent compound contained in the light-emitting layer is less than 10% by weight.

[0281] In some embodiments, the host material of the light-emitting layer is an organic compound having 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 the emitted light from increasing. In some embodiments, the host material of the light-emitting layer is an organic compound having a high glass transition temperature.

[0282] In some embodiments, the light-emitting layer comprises two or more TADF molecules with different structures. For example, the light-emitting layer can be made of the following three materials: the excited singlet energy level is highest in the order of the host material, the first TADF molecule, and the second TADF molecule. In this case, the difference ΔE between the lowest excited singlet energy level and the lowest excited triplet energy level at 77K in the first and second TADF molecules is STThey are preferably below 0.3 eV, more preferably below 0.25 eV, more preferably below 0.2 eV, more preferably below 0.15 eV, further preferably below 0.1 eV, further preferably below 0.07 eV, further preferably below 0.05 eV, further preferably below 0.03 eV, and particularly preferably below 0.01 eV. The content of the first TADF molecule in the light-emitting layer is preferably greater than the content of the second TADF molecule. Furthermore, the content of the main 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 equal to the content of the main material. In some embodiments, the composition in the light-emitting layer may be set as follows: the main material is 10 to 70 weight %, the first TADF molecule is 10 to 80 weight %, and the second TADF molecule is 0.1 to 30 weight %. In some embodiments, the composition of the light-emitting layer can be set as follows: 20-45 wt% of the host material, 50-75 wt% of the first TADF molecule, and 5-20 wt% of the second TADF molecule. In some embodiments, the light-emitting quantum yield φPL1(A) of the vapor-phase co-deposited film of the first TADF molecule and the host material (the content of the first TADF molecule in the vapor-phase co-deposited film = A wt%) and the light-emitting quantum yield φPL2(A) of the vapor-phase co-deposited film of the second TADF molecule and the host material (the content of the second TADF molecule in the vapor-phase co-deposited film = A wt%) satisfy the relationship φPL1(A)>φPL2(A). In some embodiments, the luminescence quantum yield φPL2(B) of a vapor-phase co-deposited film of the second TADF molecule and the host material (content of the second TADF molecule in the vapor-phase co-deposited film = B wt%) and the luminescence quantum yield φPL2(100) of a film of the second TADF molecule alone upon photoexcitation satisfy the relationship φPL2(B)>φPL2(100). In some embodiments, the light-emitting layer can include three TADF molecules of different structures. The exciplex and light-emitting compound of the present invention can be any of the multiple TADF compounds included in the light-emitting layer.

[0283] In some embodiments, the light-emitting layer can be composed of a material selected from the group consisting of a host material, an auxiliary 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 composed of a material consisting solely of 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 composed of a material consisting solely of atoms selected from the group consisting of carbon atoms, hydrogen atoms, and nitrogen atoms.

[0284] When the light-emitting layer includes a TADF material, the TADF material may be a known delayed fluorescent material. Preferred delayed fluorescent materials include paragraphs 0008 to 0048 and 0095 to 0133 of WO2013 / 154064, paragraphs 0007 to 0047 and 0073 to 0085 of WO2013 / 011954, paragraphs 0007 to 0033 and 0059 to 0066 of WO2013 / 011955, and paragraphs 0008 to 0095 of WO2013 / 013988. 071 and 0118 to 0133, paragraphs 0009 to 0046 and 0093 to 0134 of Japanese Patent Application Laid-Open No. 2013-256490, paragraphs 0008 to 0020 and 0038 to 0040 of Japanese Patent Application Laid-Open No. 2013-116975, paragraphs 0007 to 0032 and 0079 to 0084 of WO2013 / 133359, paragraphs 00 08 to 0054 and 0101 to 0121, paragraphs 0007 to 0041 and 0060 to 0069 of Japanese Patent Application Laid-Open No. 2014-9352, paragraphs 0008 to 0048 and 0067 to 0076 of Japanese Patent Application Laid-Open No. 2014-9224, paragraphs 0013 to 0025 of Japanese Patent Application Laid-Open No. 2017-119663, paragraphs 0013 to 0025 of Japanese Patent Application Laid-Open No. 2017-119664 Compounds encompassed by the general formula described in paragraph 26, paragraphs 0012 to 0025 of JP-A-2017-222623, paragraphs 0010 to 0050 of JP-A-2017-226838, paragraphs 0012 to 0043 of JP-A-2018-100411, and paragraphs 0016 to 0044 of WO2018 / 047853, especially exemplary compounds capable of emitting delayed fluorescence.Here, it is preferable to adopt Japanese Patent Application Laid-Open No. 2013-253121, WO2013 / 133359, WO2014 / 034535, WO2014 / 115743, WO2014 / 122895, WO2014 / 126200, WO2014 / 136758, WO2014 / 1331 21, WO2014 / 136860, WO2014 / 196585, WO2014 / 189122, WO2014 / 168101, WO2015 / 008580, WO2014 / 203840, WO2015 / 002213, WO2015 / 016200, WO 2015 / 019725, WO2015 / 072470, WO2015 / 108049, WO2015 / 080182, WO2015 / 072537, WO2015 / 080183, Japanese Patent Application Laid-Open No. 2015-129240, WO2015 / 129714, WO2015 / 1 The present invention relates to a light-emitting material capable of emitting delayed fluorescence as described in WO2015 / 29715, WO2015 / 133501, WO2015 / 136880, WO2015 / 137244, WO2015 / 137202, WO2015 / 137136, WO2015 / 146541, and WO2015 / 159541. The aforementioned publications described in this paragraph are hereby incorporated by reference as a part of this specification.

[0285] (Injection layer)

[0286] The injection layer is a layer between the electrode and the organic layer. In some embodiments, the injection layer reduces the driving voltage and enhances the luminescence brightness. In some embodiments, the injection layer comprises a hole injection layer and an electron injection layer. The injection layer can be arranged 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, the injection layer is present. In some embodiments, the injection layer is not present.

[0287] Next, preferred examples of compounds that can be used as hole injection materials are given.

[0288] [Chemical Formula 10]

[0289]

[0290] Next, preferred examples of compounds that can be used as electron-injecting materials are given.

[0291] [Chemical Formula 11]

[0292]

[0293] (Barrier layer)

[0294] The blocking layer is a layer that can block the charges (electrons or holes) and / or excitons present in the light-emitting layer from diffusing to the outside of the light-emitting layer. In some embodiments, the electron blocking layer is present between the light-emitting layer and the hole transport layer, and blocks electrons from passing through the light-emitting layer to reach the hole transport layer. In some embodiments, the hole blocking layer is present between the light-emitting layer and the electron transport layer, and blocks holes from passing through the light-emitting layer to reach the electron transport layer. In some embodiments, the blocking layer blocks excitons from diffusing to the outside of the light-emitting layer. In some embodiments, the electron blocking layer and the hole blocking layer constitute an exciton blocking layer. The term "electron blocking layer" or "exciton blocking layer" used in this specification includes a layer having both the function of an electron blocking layer and the function of an exciton blocking layer.

[0295] (Hole Blocking Layer)

[0296] The hole-blocking layer functions as an electron-transporting layer. In some embodiments, during electron transport, the hole-blocking layer prevents holes from reaching the electron-transporting layer. In some embodiments, the hole-blocking layer increases the probability of electron-hole recombination in the light-emitting layer. The materials used for the hole-blocking layer can be the same materials described above for the electron-transporting layer.

[0297] Preferred examples of compounds that can be used for the hole-blocking layer are listed below.

[0298] [Chemical Formula 12]

[0299]

[0300] [Chemical Formula 13]

[0301]

[0302] (Electron blocking layer)

[0303] The electron blocking layer transports holes. In some embodiments, during hole transport, the electron blocking layer prevents electrons from reaching the hole transport layer. In some embodiments, the electron blocking layer increases the probability of recombination between electrons and holes in the light-emitting layer. The materials used for the electron blocking layer can be the same materials described above for the hole transport layer.

[0304] Specific examples of preferred compounds that can be used as electron-blocking materials are given below.

[0305] [Chemical Formula 14]

[0306]

[0307] (Exciton blocking layer)

[0308] The exciton-blocking layer blocks the excitons generated by 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 can effectively confine the excitons in the light-emitting layer. In some embodiments, the luminous 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 is present between the hole transport layer and the light-emitting layer, or it can be adjacent to the light-emitting layer. In some embodiments, when the exciton-blocking layer is present on the cathode side, the layer is present between the light-emitting layer and the cathode, or it can be 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 the excited triplet energy, respectively, of the light-emitting material.

[0309] (Hole Transport Layer)

[0310] 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.

[0311] In some embodiments, the hole transport material has one of the following properties: 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. As examples of known hole transport materials that can be used in the present invention, there can be cited (but not limited to) triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indole and carbazole derivatives, polyaryl alkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, aromatic amine 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. Below, specific examples of preferred compounds that can be used as hole transport materials are given.

[0312] [Chemical Formula 15]

[0313]

[0314] [Chemical Formula 16]

[0315]

[0316] [Chemical Formula 17]

[0317]

[0318] (Electron Transport Layer)

[0319] 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.

[0320] In some embodiments, the electron transport material only needs to have the function of transporting electrons injected from the cathode to the light-emitting layer. In some embodiments, the electron transport material also functions as a hole blocking material. As examples of electron transport layers that can be used in the present invention, there can be cited (but not limited to) nitro-substituted fluorene derivatives, diphenylbenzoquinone derivatives, thiopyran dioxide derivatives, carbodiimide derivatives, fluorenylmethane derivatives, anthraquinone dimethane derivatives, anthrone derivatives, oxadiazole derivatives, oxadiazole 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 polymer material. Below, specific examples of preferred compounds that can be used as electron transport materials are given.

[0321] [Chemical Formula 18]

[0322]

[0323] [Chemical Formula 19]

[0324]

[0325] [Chemical Formula 20]

[0326]

[0327] [Chemical Formula 21]

[0328]

[0329] Furthermore, examples of preferred compounds that can be added to each organic layer are given. For example, addition as a stabilizing material is conceivable.

[0330] [Chemical Formula 22]

[0331]

[0332] Preferred materials that can be used in organic electroluminescent devices are specifically exemplified. However, the materials that can be used in the present invention are not limited to the following exemplified compounds. Furthermore, even compounds exemplified as materials having specific functions can be converted into materials having other functions.

[0333] (Device)

[0334] In some embodiments, the luminescent materials of the present invention are incorporated into devices, such as, but not limited to, OLED bulbs, OLED lamps, television displays, computer displays, mobile phones, and tablet computers.

[0335] In some embodiments, an electronic device comprises an anode, a cathode, and an OLED having at least one organic layer comprising a light-emitting layer between the anode and the cathode, the light-emitting layer comprising a light-emitting material of the present invention.

[0336] In some embodiments, since the light-emitting material of the present invention is a phosphor, the light-emitting layer of the OLED further comprises a fluorescent material that converts a triplet state to a singlet state.

[0337] In some embodiments, the structures described in this specification can be assembled into various photosensitive or photoactivated devices such as OLEDs or optoelectronic devices. In some embodiments, the structures can be used to promote charge movement or energy transfer within the device and / or as a hole transport material. As devices, 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 detection devices, organic photoreceptors, organic field-quenching devices (O-FQDs), light emitting electrochemical cells (LECs), or organic laser diodes (O-LASERs) can be cited.

[0338] (Light bulb or lamp)

[0339] In some embodiments, an electronic device comprises an anode, a cathode, an OLED having at least one organic layer comprising a light-emitting layer between the anode and the cathode, and an OLED driving circuit, wherein the light-emitting layer comprises the light-emitting material of the present invention.

[0340] In some embodiments, the device comprises different colored OLEDs. In some embodiments, the device comprises an array comprising a combination of OLEDs. In some embodiments, the combination of OLEDs is a 3-color combination (e.g., RGB). In some embodiments, the combination of OLEDs is a combination of non-red, non-green, non-blue colors (e.g., orange and yellow-green). In some embodiments, the combination of OLEDs is a combination of 2 colors, 4 colors, or more.

[0341] In some embodiments, the device is an OLED lamp, comprising: a circuit substrate having a first surface as a mounting surface and a second surface opposite thereto and defining at least one opening;

[0342] At least one OLED on the mounting surface, the at least one OLED configured to emit light comprising an anode, a cathode, and at least one organic layer comprising a light-emitting layer between the anode and the cathode, the light-emitting layer comprising the light-emitting material of the present invention;

[0343] a housing for a circuit board; and

[0344] At least one connector is disposed on an edge portion of the housing, and the housing and the connector define a package suitable for being mounted on a lighting device.

[0345] In some embodiments, an OLED lamp includes multiple OLEDs mounted on a circuit substrate to emit light in multiple directions. In some embodiments, a portion 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.

[0346] (display or display)

[0347] In some embodiments, the luminescent material of the present invention can be used in a display screen or display. In some embodiments, the luminescent material of the present invention is stacked onto a substrate by processes such as (but not limited to) vacuum evaporation, sedimentation, vapor deposition, or chemical vapor deposition (CVD). In some embodiments, the substrate is a photoplate structure useful in double-sided etching of pixels with unique aspect ratios. The display screen (also called a mask) can be used in the manufacturing process of an OLED display. By designing a corresponding artistic pattern, it has very steep and narrow connecting strips between pixels in the vertical direction and a wide range of oblique angle openings in the horizontal direction. Thus, while optimizing the chemical vapor deposition on the TFT backplane, it is possible to achieve fine patterning of pixels required for high-resolution displays.

[0348] By patterning the interior of the pixel, it is possible to create three-dimensional pixel openings with various aspect ratios in the horizontal and vertical directions. In addition, the use of imaged "stripes" or halftone patterns in the pixel area protects etching in specific areas until these specific patterns are undercut and removed from the substrate. In this case, all pixel areas are processed at the same etching rate, but the depth varies depending on the halftone pattern. By varying the size and spacing of the halftone pattern, etching with different protection ratios within the pixel can be performed, and localized deep etching required to form steep vertical angles can be performed.

[0349] The preferred material for vapor deposition masks is Invar. Invar is a metal alloy that is cold-rolled into thin, long sheets in a steel mill. Invar cannot be electroplated onto a rotating mandrel as a nickel mask. A suitable and cost-effective method for forming the openings in vapor deposition masks is wet chemical etching.

[0350] In some embodiments, the display screen or display pattern is a matrix of pixels on a substrate. In some embodiments, the display screen or display pattern is processed using etching methods (e.g., photolithography and electron beam etching). In some embodiments, the display screen or display pattern is processed using wet chemical etching. In yet other embodiments, the display screen or display pattern is processed using plasma etching.

[0351] (Method for manufacturing device)

[0352] OLED displays are typically manufactured by forming a large motherboard and then cutting it into unit panels. Generally speaking, each unit panel on the motherboard is formed by forming a thin-film transistor (TFT), including an active layer and source / drain electrodes, on a base substrate, applying a planarization film to the TFT, and sequentially forming a pixel electrode, light-emitting layer, counter electrode, and encapsulation layer. The unit panel is then cut from the motherboard.

[0353] In another embodiment of the present invention, a method for manufacturing an organic light emitting diode (OLED) display is provided, the method comprising:

[0354] forming a barrier layer on a base substrate of a motherboard;

[0355] forming a plurality of display units in a unit panel unit on the barrier layer;

[0356] forming an encapsulation layer on each of the display units of the unit panel;

[0357] A process of applying an organic film to the interface portion between the unit plates.

[0358] In some embodiments, the barrier layer is an inorganic film, for example, formed of SiNx, and the edge portion of the barrier layer is covered with an organic film formed of polyimide or acryl. In some embodiments, the organic film helps to gently cut the motherboard into unit board units.

[0359] In some embodiments, the thin film transistor (TFT) layer includes a light-emitting layer, a gate electrode, and a source electrode / drain electrode. Each of the multiple display units may include a thin film transistor (TFT), a planarization film formed on the TFT layer, and a light-emitting unit formed on the planarization film, wherein the organic film coated on the interface portion is formed of the same material as the planarization film and is formed simultaneously with the formation of the planarization film. In some embodiments, the light-emitting unit is connected to the TFT layer through a passivation layer, a planarization film therebetween, and an encapsulation layer covering and protecting the light-emitting unit. In some embodiments of the manufacturing method, the organic film is neither connected to the display unit nor to the encapsulation layer.

[0360] Each of the organic film and the planarization film may comprise either polyimide or acryl. In some embodiments, the barrier layer may be an inorganic film. In some embodiments, the base substrate may be formed of polyimide. The method may further include the steps of: before forming the barrier layer on one surface of the base substrate formed of polyimide, attaching a carrier substrate formed of a glass material to the other surface of the base substrate, and separating the carrier substrate from the base substrate before cutting along the interface portion. In some embodiments, the OLED display is a flexible display.

[0361] In some embodiments, the passivation layer is an organic film disposed on the TFT layer to cover 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 acryl, similar to the organic film formed on the edge portion of the barrier layer. In some embodiments, the planarization film and the organic film are formed simultaneously when manufacturing the OLED display. In some embodiments, the organic film can be formed on the edge portion 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 surrounds the edge portion of the barrier layer while contacting the barrier layer.

[0362] In some embodiments, the light emitting layer includes a pixel electrode, an opposite electrode, and an organic light emitting layer disposed between the pixel electrode and the opposite electrode. In some embodiments, the pixel electrode is connected to a source electrode / drain electrode of the TFT layer.

[0363] In some embodiments, when a voltage is applied to the pixel electrode via the TFT layer, an appropriate voltage is formed between the pixel electrode and the opposite electrode, and thus the organic light-emitting layer emits light, thereby forming an image. Hereinafter, an image forming unit including the TFT layer and the light-emitting unit is referred to as a display unit.

[0364] In some embodiments, the encapsulation layer that covers the display units and prevents external moisture penetration can be formed as a thin film-like encapsulation structure composed of alternating organic and inorganic films. In some embodiments, the encapsulation layer has a thin film-like encapsulation structure composed of multiple thin films stacked together. In some embodiments, the organic film applied to the interface portion is spaced apart from each of the multiple display units. In some embodiments, the organic film is formed such that a portion of the organic film directly contacts the base substrate, while the remaining portion of the organic film surrounds the edge portion of the barrier layer while contacting the barrier layer.

[0365] In one embodiment, the OLED display is flexible and uses a soft base substrate formed of polyimide.In some embodiments, the base substrate is formed on a carrier substrate formed of a glass material, and then the carrier substrate is separated.

[0366] In some embodiments, a 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 unit board. For example, while the base substrate is formed on the entire surface of the motherboard, the barrier layer is formed according to the size of each unit board, thereby forming grooves at the interface between the unit board and the barrier layer. Each unit board can be cut along the grooves.

[0367] In some embodiments, the manufacturing method further includes a step of cutting along the interface portion, wherein a groove is formed in the barrier layer, and at least a portion of the organic film is formed in the groove, wherein the groove does not penetrate into the base substrate. In some embodiments, the TFT layer of each unit board is formed, and a passivation layer (which is an inorganic film) and a planarization film (which is an organic film) are arranged on the TFT layer to cover the TFT layer. While forming the planarization film formed from, for example, polyimide or acryl, the groove at the interface portion is covered with an organic film formed from, for example, polyimide or acryl. This is to prevent cracking by allowing the organic film to absorb the impact generated when cutting each unit board along the groove at the interface portion. That is, if the entire barrier layer is completely exposed without the organic film, then when cutting each unit board along the groove at the interface portion, the impact generated will be transferred to the barrier layer, thereby increasing the risk of cracking. However, in one embodiment, because the groove at the interface portion between the barrier layers is covered with an organic film, it absorbs the impact that would be transferred to the barrier layer if the organic film was not present, so each unit board can be cut gently and cracking can be prevented in the barrier layer. In one embodiment, the organic film and the planarization film covering the groove of the interface portion are spaced apart from each other. For example, if the organic film and the planarization film were connected to each other as a single layer, external moisture might penetrate into the display unit through the planarization film and the portion where the organic film remains. Therefore, 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.

[0368] In some embodiments, the display unit is formed by forming the light-emitting unit, and the encapsulation layer is disposed on the display unit to cover the display unit. Thus, once the motherboard is completely manufactured, the carrier substrate supporting the base substrate is separated from the base substrate. In some embodiments, when a laser beam is emitted toward the carrier substrate, the carrier substrate separates from the base substrate due to the difference in thermal expansion coefficient between the carrier substrate and the base substrate.

[0369] In some embodiments, a motherboard is cut into unit boards. In some embodiments, a cutting machine is used to cut the motherboard along the interface between the unit boards. In some embodiments, because the grooves along the interface along which the motherboard is cut are covered with an organic film, the organic film absorbs shock during cutting. In some embodiments, cracks can be prevented from occurring in the barrier layer during cutting.

[0370] In some embodiments, the method reduces the defect rate of the product and stabilizes its quality.

[0371] In another embodiment, an OLED display includes: 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 coated on an edge portion of the barrier layer.

[0372] Example

[0373] General information about the analytical method:

[0374] The features of the present invention are described in more detail with reference to the following examples. The materials, processes, and steps described below can be modified as appropriate 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 described below. The characteristics of the samples were evaluated using NMR (500 MHz nuclear magnetic resonance manufactured by Bruker Corporation), LC / MS (liquid chromatography mass spectrometer manufactured by Waters Corporation), AC3 (manufactured by RIKEN KEIKI Co., Ltd.), a high-performance UV / Vis / NIR spectrophotometer (Lambda950 manufactured by PerkinElmer Co., Ltd.), a fluorescence spectrophotometer (FluoroMax-4 manufactured by HORIBA, Ltd.), a photon multichannel analyzer (PMA-12C10027-01 manufactured by Hamamatsu Photonics KK), an absolute PL quantum yield measurement system (C11347 manufactured by Hamamatsu Photonics KK), an automatic current-voltage luminance measurement system (ETS-170 manufactured by System Engineering Laboratory Co., Ltd.), a lifetime measurement system (EAS-26C manufactured by System Engineering Laboratory Co., Ltd.), and a streak camera (C4334 manufactured by Hamamatsu Photonics KK).

[0375] (Example 1) Preparation and evaluation of thin films 1

[0376] At vacuum degree 10 -3 Pa conditions, the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the regulating compound PYD2Cz were vapor deposited on a quartz substrate in a mass ratio of 1:1:1 to prepare a thin film DAN with a thickness of 70 nm.

[0377] Film D was prepared by vapor deposition of TrisPCz alone under the same conditions.

[0378] Under the same conditions, film A was prepared by vapor deposition of only SF3-TRZ.

[0379] Thin film N was prepared by vapor deposition of only PYD2Cz under the same conditions.

[0380] Under the same conditions, TrisPCz and SF3-TRZ were vapor deposited at a mass ratio of 1:1 to prepare thin film DA.

[0381] Under the same conditions, TrisPCz and PYD2Cz were vapor deposited at a mass ratio of 1:1 to prepare the thin film DN.

[0382] Under the same conditions, SF3-TRZ and PYD2Cz were vapor deposited in a mass ratio of 1:1 to prepare thin film AN.

[0383] exist Figure 2 The following shows the energy levels of the compounds used in the light-emitting layer of Example 1. The light-emitting material satisfying the relationship of Formula (A), Formula (B1), and Formula (B2) is a thin film DAN.

[0384] exist Figure 3 The results are shown when each of the prepared thin films was irradiated with light having a wavelength of 300 nm at 300 K and the emission spectrum was measured. Figure 3 The diagram shows that an exciplex is formed by the donor compound TrisPCz and the acceptor compound SF3-TRZ to emit light, and that the emission spectrum based on the exciplex does not change even if the regulating compound PYD2Cz is further added.

[0385] The luminescence quantum yield (PLQY) was measured to be 31% for thin film DA and 46% for thin film DAN, confirming that the luminescence efficiency based on the exciplex was significantly improved by further adding the regulating compound.

[0386] (Example 2) Preparation and evaluation of thin films 2

[0387] A thin film was formed using the same procedures as in Example 1, except that the mass ratios of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the modulator compound PYD2Cz were changed to those shown in the table below. Luminescence spectra were measured in the same manner as in Example 1, and the spectrum from 300 to 700 nm was identical to that of the thin film DAN in Example 1. Furthermore, a comparison of transient decay curves revealed a trend toward longer delayed fluorescence lifetimes with increasing mass ratios of the modulator compound PYD2Cz. Furthermore, a comparison of luminescence quantum yields (PLQYs) revealed a trend toward higher PL ratios of the modulator compound PYD2Cz.

[0388] [Table 1]

[0389]

[0390] (Example 3) Preparation and evaluation of thin films 3

[0391] Except for the change of using mCBP as the regulating compound, the same procedure as in Example 2 was followed to form thin films having the mass ratios shown in the following table. Figure 4 Shown are the energy levels of the compounds used in the light-emitting layer of Example 3. Also for the thin film using mCBP as the modifier compound, it was confirmed that the higher the mass ratio of the modifier compound, the longer the delayed fluorescence lifetime and the higher the emission quantum yield.

[0392] [Table 2]

[0393]

[0394] (Example 4) Preparation and Evaluation of Organic Electroluminescent Device

[0395] On a glass substrate with an anode composed of indium / tin oxide (ITO) with a thickness of 50 nm, a vacuum vapor deposition method was used to deposit the anode at a vacuum degree of 10 -5 Each thin film was stacked under Pa. First, HAT-CN with a thickness of 10nm was formed on ITO, NPD with a thickness of 30nm was formed thereon, and TrisPCz with a thickness of 10nm was formed. Then, the donor compound TrisPCz, the acceptor compound SF3-TRZ and the regulating compound PYD2Cz were vapor-co-deposited from different vapor deposition sources at a mass ratio of 1:1:1 to form a 30nm thick light-emitting layer. Next, SF3-TRZ with a thickness of 10nm was formed, and SF3-TRZ and Liq with a thickness of 30nm were formed thereon at a mass ratio of 7:3. In addition, a cathode was formed by vapor deposition of lithium fluoride (LiF) with a thickness of 2.0nm, followed by vapor deposition of aluminum (Al) with a thickness of 100nm, and an organic electroluminescent device (element DAN) was produced.

[0396] Then, an organic electroluminescent device (device DA) was produced by the same procedure except that the donor compound TrisPCz and the acceptor compound SF3-TRZ were vapor-phase co-deposited at a mass ratio of 1:1 to form a light-emitting layer.

[0397] Furthermore, the donor compound TrisPCz, the acceptor compound SF3-TRZ, the modulator compound PYD2Cz, and the luminescent compound 4DPA-Pyr were vapor-phase co-deposited from different vapor deposition sources to form a light-emitting layer. Aside from this change, an organic electroluminescent device (element DANE) was fabricated using the same steps. The mass ratio of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the modulator compound PYD2Cz was set to 1:1:1. Furthermore, the luminescent compound 4DPA-Pyr was set to 1% by mass relative to the combined amount of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the modulator compound PYD2Cz.

[0398] In addition, an organic electroluminescent device (DAE) was produced using the same steps except for the change in the vapor deposition source, whereby the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the luminescent compound 4DPA-Pyr were vapor-phase co-deposited to form the luminescent layer. The mass ratio of the donor compound TrisPCz to the acceptor compound SF3-TRZ was set to 1:1. Furthermore, the luminescent compound 4DPA-Pyr was set to 1% by mass relative to the combined amount of the donor compound TrisPCz and the acceptor compound SF3-TRZ.

[0399] exist Figure 5 The following table shows the measurement results of the emission spectra of the four fabricated elements. Element DAN and element DA have identical emission spectra in the 300-700 nm range, and element DANE and element DAE have identical emission spectra in the 300-700 nm range. The maximum emission wavelengths of elements DANE and DAE are slightly shorter than those of elements DAN and DA. On the other hand, the half-value widths of elements DANE and DAE are narrower than those of elements DAN and DA.

[0400] The time required for the emission intensity to decrease to 95% (LT95) was the longest for DANE, which was 3.0 times that of DAE. It was confirmed that the addition of the regulating compound significantly prolonged the emission lifetime.

[0401] (Example 5) Solubility Test

[0402] A solubility test was performed on a mixture of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the modulator compound PYD2Cz in 1 ml of toluene. The masses of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the modulator compound PYD2Cz were 4.5 mg, 4.5 mg, and 1.0 mg, respectively (mixture DAN1).

[0403] In addition, solubility testing (mixtures DAN2 and DAN3) was conducted using the same procedures as for composition DAN1, except that the mass ratios of the donor compound TrisPCz, the acceptor compound SF3-TRZ, and the mixed compound PYD2Cz were changed to those shown in the table below. Dissolution was visually confirmed for all compositions. This confirms that the combination of the present invention is applicable to coating-type devices.

[0404] [Table 3]

[0405]

[0406] [Chemical Formula 23]

[0407]

[0408] Industrial applicability

[0409] The luminescent material of the present invention exhibits excellent luminous efficiency and / or luminescent lifetime. Therefore, the luminescent material of the present invention can be effectively used as a charge transport material for organic light-emitting diodes (OLEDs), such as organic electroluminescent devices, thereby providing an OLED that achieves at least one of high luminous efficiency and long luminescent lifetime. Therefore, the present invention has high industrial applicability.

[0410] Explanation of symbols

[0411] 1-substrate, 2-anode, 3-hole injection layer, 4-hole transport layer, 5-light-emitting layer, 6-electron transport layer, 7-cathode.

Claims

1. A light-emitting material comprising, in addition to a donor compound and an acceptor compound that form an exciplex, a modulator compound that is different from the donor compound and the acceptor compound, and satisfying the relationship of the following formula (A), formula (B1), and formula (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 (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 modulator 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 modulator compound. The donor compound is a compound having the following skeleton, The receptor compound is a compound having the following skeleton, The regulating compound is a compound selected from the group consisting of a compound having a donor site and an acceptor site in the molecule and a compound having two or more donor sites and a linker connecting the donor sites in the molecule, wherein the linker is a substituted or unsubstituted arylene group, a substituted or unsubstituted alkenylene group, a substituted or unsubstituted alkynylene group, or a group formed by linking 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. And the luminescent material satisfies the following conditions (1) and (2), Condition (1): the luminescent material comprises a mixture of the donor compound, the acceptor compound and the regulating compound, Condition (2): The content of the adjusting compound in the light-emitting material is 5% by mass or more.

2. The luminescent material according to claim 1, further satisfying the relationship of the following formula (C): Formula (C) HOMO(D)≥HOMO(A)+0.6eV.

3. The luminescent material according to claim 1, further satisfying the relationship of the following formula (D) and formula (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 regulating compound.

4. The luminescent material according to any one of claims 1 to 3, wherein The content of the regulating compound is 30% by mass or more.

5. The luminescent material according to any one of claims 1 to 3, wherein The emission intensity from the exciplex is 10 times greater than that from the modulating compound. The luminescent material according to claim 1 , further comprising a luminescent compound.

7. The luminescent material according to claim 6, wherein The emission intensity from the light-emitting compound is 10 times or more higher than the emission intensity from the exciplex.

8. The luminescent material according to claim 6, wherein The luminescence intensity from the luminescent compound is 50 times greater than the luminescence intensity from the regulating compound. 9 . A delayed phosphor comprising the luminescent material according to claim 1 . 10 . An organic light emitting diode comprising the light emitting material according to claim 1 .

11. An organic light emitting diode comprising an anode, a cathode, and at least one organic layer comprising a light emitting layer between the anode and the cathode, wherein: The light-emitting layer comprises the light-emitting material according to any one of claims 1 to 5.

12. An organic light emitting diode comprising an anode, a cathode, and at least one organic layer comprising a light emitting layer between the anode and the cathode, wherein: The light-emitting layer comprises the light-emitting material according to any one of claims 6 to 8.

13. A display comprising the light-emitting material according to any one of claims 1 to 8.

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