Light emitting material, light emitting device, display device

Abstract

The application relates to a luminescent material, which comprises luminescent molecules selected from any one of molecules with the following general molecular structure: wherein X1-X4 are independently selected from O or S, ring Ar1-Ar6 are independently selected from an aromatic ring or an aromatic heterocyclic ring, Ar7 and Ar8 are independently selected from an aromatic heterocyclic ring, Y1 and Y2 are independently selected from C or N, R1-R4 are substituents, k1-k4 respectively represent the number of R1-R4, and k1-k4 are all integers not less than 1. The application realizes that the luminescent molecules simultaneously have a large f and a small DeltaEST.

Description

Technical Field

[0001] This application relates to the field of display technology, and more particularly to light-emitting diode materials. Background Technology

[0002] Thermally activated delayed fluorescence (TADF) materials have recently become a research frontier due to their significant advantage of achieving 100% exciton utilization using no precious metal-free organic molecules. A key characteristic of TADF materials is their near-close lowest-energy singlet (S1) and triplet (T1) excited states, enabling dark T1 excitons to be upconverted to radiative S1 excitons at room temperature via reverse systematic crossover (RISC). For ideal TADF materials, a fast exciton decay process is essential, controlled by both fast triplet upconversion and singlet radiation. The former requires a small singlet-triplet bandgap (ΔEST), while the latter requires a large oscillator strength (f); however, these are conflicting factors because they exhibit opposite dependencies on the orbital overlap integral.

[0003] The conventional design principle for most TADF materials can be simplified to donor (D)-acceptor (A) or D-π-A structures with one or more donors or acceptors, where the luminescence behavior is greatly influenced by the molecular electronic excitation properties. For TADF molecules with completely separated boundary molecular orbitals, isolated donor-acceptor long-range charge transfer (LR-CT) excitations can be expected, which favors smaller ΔEST and smaller f. A conventional approach to address this problem is to introduce some orbital overlap on the π-bridge, hybrid local excitation (LE), to increase the f value. However, in molecular design, carefully balancing the appropriate ratio of LR-CT and LE excitations to achieve smaller ΔEST and larger f is quite difficult, and the ΔEST of most TADF molecules remains too large. Summary of the Invention

[0004] This application provides a luminescent material, a luminescent device, and a display device to solve the technical problem that TADF molecules are difficult to simultaneously possess both a small ΔEST and a large f.

[0005] In a first aspect, embodiments of this application provide a luminescent material, the luminescent material comprising luminescent molecules, the luminescent molecules being selected from any one of molecules having the following general molecular structural formulas:

[0006]

[0007] Among them, X1 to X4 are each independently selected from O or S.

[0008] Rings Ar1 through Ar6 are each independently selected from aromatic rings or aromatic heterocyclic rings, and Ar7 and Ar8 are each independently selected from aromatic heterocyclic rings.

[0009] Y1 and Y2 are each independently selected from C or N.

[0010] R1 to R4 are substituents.

[0011] k1 to k4 refer to the quantities of R1 to R4 respectively, and k1 to k4 are all integers not less than 1.

[0012] In some embodiments of this application, the luminescent material further includes fluorescent molecules.

[0013] In some embodiments of this application, k1 to k4 are all integers in the interval [1, 10].

[0014] In some embodiments of this application, R1 to R4 are each independently selected from hydroxyl, cyano, nitro, amido, hydrazine, hydrazone, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkoxy, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic alkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heterocyclic alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted aryloxy, substituted or unsubstituted arylthio, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroaryloxy, substituted or unsubstituted heteroarylthio, substituted or unsubstituted monovalent nonaromatic fused polycyclic group, and substituted or unsubstituted monovalent nonaromatic fused heterocyclic group.

[0015] In some embodiments of this application, the substituted or unsubstituted monovalent non-aromatic fused heterocyclic group includes:

[0016] -C(Q1)(Q2)(Q3), -Si(Q1)(Q2)(Q3), -B(Q1)(Q2), -N(Q1)(Q2), -P(Q1)(Q2), -C(=O)(Q1), -S(=O)(Q1), -S(=O)2(Q1), -P(=O)(Q1)(Q2) and -P(=S)(Q1)(Q2),

[0017] Among them, Q1 to Q3 are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl group, cyano group, nitro group, amino group, amido group, hydrazine group, hydrazone group, C1-C60 alkyl group, C2-C60 alkenyl group, C2-C60 alkynyl group, C1-C60 alkoxy group, C3-C10 cycloalkyl group, C1-C10 heterocyclic alkyl group, C3-C10 cycloalkenyl group, C1-C10 heterocyclic alkenyl group, C6-C60 aryl group, C1-C60 heteroaryl group, monovalent non-aromatic fused polycyclic group, monovalent non-aromatic fused heterocyclic group, biphenyl group and terphenyl group.

[0018] In some embodiments of this application, the luminescent molecules, Unit and

[0019] Unit, and The rotation angles between the units are all no less than 46° and no more than 52°. The unit is selected from one of the following groups:

[0020] In some embodiments of this application, the luminescent molecule is selected from one of the following molecules:

[0021]

[0022]

[0023] Secondly, embodiments of this application provide a light-emitting device, the light-emitting device comprising: an anode stacked in layers;

[0024] A light-emitting layer, wherein the light-emitting layer comprises the light-emitting material described in any embodiment of the first aspect;

[0025] cathode.

[0026] Thirdly, embodiments of this application provide a display device, the display device including the light-emitting device described in any embodiment of the second aspect.

[0027] The technical solutions provided in this application have the following advantages compared with the prior art:

[0028] The luminescent material provided in this application includes luminescent molecules formed by connecting equivalent multiple resonance acceptors to spatially loosely spaced donors. This structure produces a hybrid orbital distribution, including hybrid donor-acceptor LR-CT and bridging-phenyl SR-CT features, enabling the luminescent molecules to simultaneously possess large f and small ΔEST. The equivalent radiation channel can be further expanded f without affecting ΔEST. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of the upright device provided in the embodiments of this application;

[0032] Figure 2 This is a schematic diagram of the structure of the inverted device provided in the embodiments of this application;

[0033] Figure 3 This is a schematic diagram of the structure of the light-emitting device provided in Embodiment 1 of this application. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] Unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any conflict, this specification shall prevail.

[0036] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0037] Existing TADF molecules are difficult to simultaneously possess both a small ΔEST and a large f.

[0038] The technical solution provided in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0039] In a first aspect, embodiments of this application provide a luminescent material, the luminescent material comprising luminescent molecules, the luminescent molecules being selected from any one of molecules having the following general molecular structural formulas:

[0040]

[0041] Among them, X1 to X4 are each independently selected from O or S.

[0042] Rings Ar1 through Ar6 are each independently selected from aromatic rings or aromatic heterocyclic rings, and Ar7 and Ar8 are each independently selected from aromatic heterocyclic rings.

[0043] Y1 and Y2 are each independently selected from C or N.

[0044] R1 to R4 are substituents.

[0045] k1 to k4 refer to the quantities of R1 to R4 respectively, and k1 to k4 are all integers not less than 1.

[0046] The R1 group is attached to the Ar3 ring. It's easy to understand that the Ar3 ring has several substitution sites where the R1 group can attach. The number of R1 groups, k1, means that k1 R1 groups are attached to k1 substitution sites on the Ar3 ring. It's easy to understand that k1 should not exceed the total number of substitution sites on the Ar3 ring. The meanings of k1 to k4 are understood in the same way.

[0047] The luminescent molecule described in this application has an ADA-type molecular configuration. It is readily understood that in the luminescent molecule,

[0048] Unit and Each unit cell contains a boron atom, classifying it as an electron-deficient structure. Unit and Unit connected to On the unit, the equivalent multiple resonant acceptor is attached to the spatially relatively loose donor. This structure not only produces a hybrid orbital distribution, including hybrid donor-acceptor LR-CT and bridging-phenyl SR-CT features, but also achieves large f and small ΔEST. Furthermore, it allows the equivalent radiation channel to be further expanded f without affecting ΔEST.

[0049] Furthermore, while maintaining the radiation rate (kr) at the reverse intersystem crossing (krISC), the spin-orbit coupling (SOC) can be expanded by introducing heavy atoms (such as introducing S atoms to replace O atoms) and modulating the localized state and charge-transfer state (CT state) energy levels, thereby further improving kRISC.

[0050] The luminescent material described in this application may consist entirely of the luminescent molecules described in this application; it may also include other organic luminescent molecules, such as those known in the art, selected from, but not limited to, at least one of diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives or fluorene derivatives, blue-emitting TBPe fluorescent materials, green-emitting TTPA fluorescent materials, orange-emitting TBRb fluorescent materials, and red-emitting DBP fluorescent materials. The luminescent material described in this application may also include conventional dopants.

[0051] The luminescent material provided in this application comprises luminescent molecules formed by attaching equivalent multiple resonance acceptors to spatially relatively loose donors. This structure produces a hybrid orbital distribution, including hybrid donor-acceptor LR-CT and bridging-phenyl SR-CT features, enabling the luminescent molecules to simultaneously possess large f and small ΔEST. The equivalent radiation channel can be further expanded f without affecting ΔEST.

[0052] In some embodiments of this application, rings Ar1 to Ar6 are each independently selected from aromatic rings or aromatic heterocycles of no more than 60 elements, and Ar7 and Ar8 are each independently selected from aromatic heterocycles of no more than 60 elements.

[0053] In some embodiments of this application, the luminescent material further includes fluorescent molecules.

[0054] The fluorescent molecule can be any molecule exhibiting fluorescence. The addition of the fluorescent molecule allows it to act as a guest in the multiple resonance (MR) effect, with the luminescent molecule functioning as a sensitizer. It is understood that the prerequisite for adding the fluorescent molecule as an MR guest is that there is effective spectral overlap between its absorption spectrum and that of the luminescent molecule.

[0055] In some embodiments of this application, k1 to k4 are all integers in the interval [1, 10].

[0056] In some embodiments of this application, R1 to R4 are each independently selected from hydroxyl, cyano, nitro, amido, hydrazine, hydrazone, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkoxy, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic alkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heterocyclic alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted aryloxy, substituted or unsubstituted arylthio, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroaryloxy, substituted or unsubstituted heteroarylthio, substituted or unsubstituted monovalent nonaromatic fused polycyclic group, and substituted or unsubstituted monovalent nonaromatic fused heterocyclic group.

[0057] In some embodiments of this application, R1 to R4 are each independently selected from hydroxyl, cyano, nitro, amidine, hydrazine, hydrazone, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C2-C60 alkynyl, substituted or unsubstituted C1-C60 alkoxy, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C1-C10 heterocycloalkyl, substituted or unsubstituted C3-C10 cycloalkenyl, Substituted or unsubstituted C1-C10 heterocyclic alkenyl groups, substituted or unsubstituted C6-C60 aryl groups, substituted or unsubstituted C6-C60 aryloxy groups, substituted or unsubstituted C6-C60 arylthio groups, substituted or unsubstituted C1-C60 heteroaryl groups, substituted or unsubstituted C1-C60 heteroaryloxy groups, substituted or unsubstituted C1-C60 heteroarylthio groups, substituted or unsubstituted monovalent non-aromatic fused polycyclic groups, and substituted or unsubstituted monovalent non-aromatic fused heterocyclic groups.

[0058] It should be noted that C1 to C60 alkyl refers to alkyl groups having 1 to 60 carbon atoms. Other related descriptions should be understood in the same way.

[0059] In some embodiments of this application, the substituted or unsubstituted monovalent non-aromatic fused heterocyclic group includes:

[0060] -C(Q1)(Q2)(Q3), -Si(Q1)(Q2)(Q3), -B(Q1)(Q2), -N(Q1)(Q2), -P(Q1)(Q2), -C(=O)(Q1), -S(=O)(Q1), -S(=O)2(Q1), -P(=O)(Q1)(Q2) and -P(=S)(Q1)(Q2),

[0061] Among them, Q1 to Q3 are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl group, cyano group, nitro group, amino group, amido group, hydrazine group, hydrazone group, C1-C60 alkyl group, C2-C60 alkenyl group, C2-C60 alkynyl group, C1-C60 alkoxy group, C3-C10 cycloalkyl group, C1-C10 heterocyclic alkyl group, C3-C10 cycloalkenyl group, C1-C10 heterocyclic alkenyl group, C6-C60 aryl group, C1-C60 heteroaryl group, monovalent non-aromatic fused polycyclic group, monovalent non-aromatic fused heterocyclic group, biphenyl group and terphenyl group.

[0062] In some embodiments of this application, the luminescent molecules, Unit and Unit, and The rotation angle between units is no less than 46° and no more than 52°.

[0063] Those skilled in the art can adjust the rotation angle by changing the configuration of the luminescent molecule and adjusting its steric hindrance. For example, the steric hindrance of the luminescent molecule can be adjusted by changing the substituents on rings Ar1, Ar2, Ar7, and Ar8, thereby adjusting the rotation angle.

[0064] In some embodiments of this application, the luminescent molecules, The unit is selected from one of the following groups:

[0065]

[0066] In some embodiments of this application, the luminescent molecule is selected from one of the following molecules:

[0067]

[0068]

[0069] Secondly, this application provides a light-emitting device, please refer to... Figure 1 , Figure 2 The light-emitting device comprises layers stacked together:

[0070] Anode 2;

[0071] Light-emitting layer 6, wherein the material of light-emitting layer 6 is the light-emitting material described in any embodiment of the first aspect of this application;

[0072] Cathode 10.

[0073] Those skilled in the art will understand that electroluminescent devices generally also include a substrate. Please refer to [link / reference needed]. Figure 1 The electroluminescent device described in this application can be a positively positioned device with the anode 2 disposed on the substrate 1. The positively positioned device includes:

[0074] Substrate 1;

[0075] Anode 2 is disposed on the substrate 1;

[0076] The light-emitting layer 6 is disposed on the anode 2;

[0077] A cathode 10 is disposed on the light-emitting layer 6.

[0078] Please refer to Figure 2 The electroluminescent device described in this application can also be an inverted device in which the cathode 10 is disposed on the substrate 1. The inverted device includes:

[0079] Substrate 1;

[0080] A cathode 10 is disposed on the substrate 1;

[0081] Light-emitting layer 6 disposed on the cathode 10;

[0082] Anode 2 is disposed on the light-emitting layer 6.

[0083] Those skilled in the art will understand that the light-emitting device can be a top-emitting device or a bottom-emitting device.

[0084] Those skilled in the art will understand that the substrate 1 can be a transparent rigid or flexible material, such as glass, polyimide, etc., which can realize rigid substrate display and flexible display.

[0085] Those skilled in the art will understand that the materials of the anode 2 and the cathode 10 can be one or more of metals, carbon materials, and metal oxides. Metals can be, for example, one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, and Mg. Carbon materials can be, for example, one or more of graphite, carbon nanotubes, graphene, and carbon fibers. Metal oxides can be doped or undoped metal oxides, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, as well as composite electrodes with metal sandwiched between doped or undoped transparent metal oxides.

[0086] The light-emitting device described in this application is based on the light-emitting material described in the first aspect. The specific implementation of the light-emitting device can be referred to the embodiments of the first aspect and common knowledge in the art. Since the light-emitting device adopts some or all of the technical solutions of the embodiments of the first aspect, it has at least all the beneficial effects brought about by the technical solutions of the embodiments of the first aspect, which will not be repeated here.

[0087] In some embodiments of this application, the light-emitting device further includes at least one of hole injection layer 3, hole transport layer 4, electron transport layer 8, and electron injection layer 9.

[0088] Those skilled in the art will understand that the material of the hole injection layer 3 is a material known in the art for use in hole injection layers. The material of the hole injection layer 3 may be selected from materials with hole injection capability, including but not limited to poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethylethane (F4-TCNQ), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzphenanthrene (HATCN), copper polyester carbonate (CuPc), transition metal oxides, and one or more transition metal chalcogenides.

[0089] Those skilled in the art will understand that the material of the hole transport layer 4 can be selected from organic materials with hole transport capabilities, including but not limited to poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB), polyvinylcarbazole (PVK), poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine) (poly-TPD), poly(9,9-dioctylfluorene-co-bis-N,N-phenyl-1,4-phenylenediamine) (PFB), and 4,4',4”-tris(carbazole-9-yl)triphenylamine (TCATA). The hole transport layer may be selected from one or more of the following: 4,4'-bis(9-carbazole)biphenyl (CBP), N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), doped graphene, undoped graphene, and C60. The hole transport layer material may also be selected from inorganic materials with hole transport capabilities, including but not limited to one or more of doped or undoped NiO, WO3, MoO3, and CuO.

[0090] Those skilled in the art will understand that the electron transport layer includes an electron transport material, which includes, but is not limited to, at least one of ZnO, TiO2, Cs2CO3, or Alq3.

[0091] Those skilled in the art will understand that the electron injection layer 9 material includes at least one of Li2O, K2SiO3, LiF, Yb, Mg, and Ca.

[0092] In some embodiments of this application, the light-emitting device further includes at least one of a hole blocking layer 7 and an electron blocking layer 5.

[0093] Those skilled in the art will understand that the electron blocking layer 5 has hole transport characteristics and can be a red light-emitting auxiliary layer, a green light-emitting auxiliary layer, or a blue light-emitting auxiliary layer. The material of the electron blocking layer 5 can be an aromatic amine or carbazole material, such as 4,4-bis(9-carbazole)biphenyl (CBP), 9-phenyl-3-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (PCzPA), etc. The thickness of the electron blocking layer 5 can be 5 to 50 nm.

[0094] Those skilled in the art will understand that the hole-blocking layer 7 includes at least one of an aromatic heterocyclic compound and a compound having phosphine oxide substituents on the heterocycle. The aromatic heterocyclic compound may be, for example, an imidazole derivative such as benzimidazole derivative, imidazopyridine derivative, or benzimidazolephenanthridine derivative, or a azine derivative such as a pyrimidine derivative or a triazine derivative, or a compound containing a nitrogen-containing six-membered ring structure such as a quinoline derivative, isoquinoline derivative, or phenanthreneroline derivative, having phosphine oxide substituents on the heterocycle. Compounds such as these can be 2,2'-(1,3-phenyl)bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole] (OXD-7), 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenyl)-1,2,4-triazole (TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole (p-EtTAZ), phenanthroline (BPhen), bromocresol purple (BCP), etc.

[0095] Thirdly, embodiments of this application provide a display device, which includes the light-emitting device described in any embodiment of the second aspect. Those skilled in the art will understand that the display device can be any display device using OLED in the art, including but not limited to television screens, mobile phone screens, and iPad screens. The display device is implemented based on the light-emitting device described in the second aspect, and specific implementations of the display device can refer to the embodiments of the second aspect. Since the display device adopts some or all of the technical solutions of the embodiments of the second aspect, it at least has all the beneficial effects brought about by the technical solutions of the embodiments of the second aspect, which will not be elaborated further here.

[0096] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0097] Example 1

[0098] This embodiment first provides a luminescent material composed of luminescent molecule T1 and 9-(3-(9H-carbazole-9-yl)phenyl)9H3,9-biscarbazole (mCPBC), with a mass ratio of T1 to mCPBC of 20:80.

[0099] The luminescent molecule T1 is synthesized by the following method:

[0100] Tris(dibenzylacetone)dipalladium(0) (1.10 g, 1.2 mmol), 1,2,3-tribromobenzene (6.30 g, 20 mmol), tri-tert-butyltetrafluorophosphine (1.39 mg, 4.8 mmol), and disodium tert-butyl (11.5 g, 120 mmol) were dissolved in toluene (200 mL) under a nitrogen atmosphere. After stirring at 90 °C for 16 hours, the reaction mixture was cooled to room temperature. The reaction mixture was filtered through a silica gel pad (eluent: toluene) and the solvent was removed under vacuum. The chemical equations involved are as follows:

[0101]

[0102] A butyllithium solution (7.75 mL, 1.59 M, 12 mmol) in hexane was slowly added to 40 mL of toluene (6.06 g, 8.2 mmol) at 78 °C under a nitrogen atmosphere. After stirring at 0 °C for 2 h, boron tribromide (1.58 mL, 16 mmol) was added at 0 °C. After stirring at 50 °C for 14 h, the reaction mixture was diluted with 20 mL of dichloromethane and quenched at 0 °C with phosphate buffer (pH 6.8, 100 mL). The chemical reaction equations involved are as follows:

[0103]

[0104] A mixture of 5-phenyl-5,11-dihydroindole[3,2-b]carbazole (3.00 mmol), 7-bromo-3,11-bis(trifluoromethyl)-5,9-dioxa-A-13b-borona[3,2,1-de]anthracene (3.29 mmol), Pd2(dba)3 (0.22 mmol), [(t-Bu)3PH][BF4] (0.72 mmol), and t-BuONa (7.18 mmol) in m-xylene (60 mL) was stirred at 140 °C under a N2 atmosphere for 24 h. After cooling to room temperature, the mixture was washed with brine and dried over anhydrous sodium sulfate. After removing the solvent, the mixture was purified by column chromatography on silica gel using petroleum ether / dichloromethane (5:1, v / v) as the eluent to obtain a pure yellow powder, i.e., the luminescent molecule T1. The chemical reaction involved is as follows:

[0105]

[0106] Please refer to Figure 3 This embodiment provides an electroluminescent device having the following structure:

[0107] Glass substrate 1 / Anode 2 (ITO) / Hole injection layer 3 (40nm) / Hole transport layer 4 (10nm) / Light-emitting layer 6 (24nm) / Hole blocking layer 7 (10nm) / Electron transport layer 8 (30nm) / Electron injection layer 9 (0.5nm) / Cathode 10 (150nm)

[0108] The hole injection layer 3 is made of 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC), the hole transport layer 4 is made of 4,4',4”-tris(carbazole-9-yl)triphenylamine (TCTA), the light-emitting layer 6 is made of the light-emitting material provided in this embodiment, the hole blocking layer 7 is made of 4,6-bis(3-(9h-carbazole-9-yl)phenyl)pyrimidine (CzPhPy), the electron transport layer 8 is made of 9,10-bis(6-phenylpyridin-3-yl)anthracene (DPPyA), the electron injection layer 9 is made of LiF, and the cathode 10 is made of Al.

[0109] The light-emitting device described in this embodiment is prepared through the following steps:

[0110] The fabrication process of the light-emitting device is as follows:

[0111] The glass substrate 1 containing ITO was ultrasonically treated in a cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone-ethanol mixed solvent, and baked in a clean environment until all moisture was removed.

[0112] A glass plate containing ITO is placed in a vacuum chamber and evacuated to 1×10⁻⁵ to 1×10⁻⁶. Hole injection material is vacuum-deposited on the side of ITO away from the glass plate to form a hole injection layer 3.

[0113] Hole transport material is vapor-deposited on the side of hole injection layer 3 away from ITO to form hole transport layer 4;

[0114] A light-emitting material is vacuum-deposited on the side of the hole transport layer 4 away from the hole injection layer 3 to form a light-emitting layer 6;

[0115] Hole blocking material is vacuum-deposited on the side of the light-emitting layer 6 away from the electron blocking layer 5 to form a hole blocking layer 7;

[0116] Electron transport material is vacuum-deposited on the side of hole blocking layer 7 away from light-emitting layer 6 to form electron transport layer 8.

[0117] Electron injection material is vacuum-deposited on the side of electron transport layer 8 away from hole blocking layer 7 to form electron injection layer 9.

[0118] A cathode 10 is formed by depositing an Al layer in the electron injection layer 9 away from the electron transport layer 8, thus obtaining the light-emitting device.

[0119] Example 2

[0120] The only difference between this embodiment and Embodiment 1 is that:

[0121] The luminescent material is composed of luminescent molecules T6 and mCPBC, with a mass ratio of T6 to mCPBC of 20:80.

[0122] The luminescent molecule T6 is synthesized by the following method:

[0123] A mixture of 5-phenyl-5,11-dimethyl[3,2-b]pyridine (3.00 mmol), 7-bromo-3,11-bis(trifluoromethyl)-5,9-dioxa-A-13b-borona[3,2,1-de]anthracene (3.29 mmol), Pd2(dba)3 (0.22 mmol), [(t-Bu)3PH][BF4] (0.72 mmol), and t-BuONa (7.18 mmol) in m-xylene (60 mL) was stirred at 140 °C under a N2 atmosphere for 24 h. After cooling to room temperature, the mixture was washed with brine and dried over anhydrous sodium sulfate. After solvent removal, the mixture was purified by column chromatography on silica gel using petroleum ether / dichloromethane (5:1, v / v) as the eluent to obtain a yellow powder, i.e., the luminescent molecule T6. The chemical reaction involved is as follows:

[0124]

[0125] Example 3

[0126] The only difference between this embodiment and Embodiment 1 is that:

[0127] The luminescent material is composed of luminescent molecules T9 and mCPBC, with a mass ratio of T9 to mCPBC of 20:80.

[0128] The luminescent molecule T9 is synthesized by the following method:

[0129] A mixture of 5-phenyl-5,11-dioxo[3,2-b]pyridine (3.00 mmol), 7-bromo-3,11-bis(trifluoromethyl)-5,9-dioxa-A-13b-borona[3,2,1-de]anthracene (3.29 mmol), Pd2(dba)3 (0.22 mmol), [(t-Bu)3PH][BF4] (0.72 mmol), and t-BuONa (7.18 mmol) in m-xylene (60 mL) was stirred for 24 h at 140 °C under a N2 atmosphere. After cooling to room temperature, the mixture was washed with brine and dried over anhydrous sodium sulfate. After solvent removal, the mixture was purified by column chromatography on silica gel using petroleum ether / dichloromethane (5:1, v / v) as the eluent to obtain an orange-yellow powder, i.e., the luminescent molecule T9. The chemical reaction formulas involved are as follows:

[0130]

[0131] Example 4

[0132] The only difference between this embodiment and Embodiment 1 is that:

[0133] The luminescent material is composed of luminescent molecules T1, mCPBC, and DBN-ICz, with a mass ratio of T1:79:1.

[0134] The molecular formula of DBN-ICz is:

[0135]

[0136] Example 5

[0137] The only difference between this embodiment and Embodiment 1 is that:

[0138] The luminescent material is composed of luminescent molecules T6, mCPBC, and DBN-ICz, with a mass ratio of T6, mCPBC, and DBN-ICz of 20:79:1.

[0139] Example 6

[0140] The only difference between this embodiment and Embodiment 1 is that:

[0141] The luminescent material is composed of luminescent molecules T9, mCPBC, and DBN-ICz, with a mass ratio of 20:79:1.

[0142] Comparative Example 1

[0143] The only difference between this comparative example and Example 1 is that:

[0144] The luminescent material is composed of 1TICz and mCPBC, with a mass ratio of 1TICz to mCPBC of 20:80.

[0145] The molecular formula of 1TICz is:

[0146]

[0147] Comparative Example 2

[0148] The only difference between this comparative example and Example 1 is that:

[0149] The luminescent material is composed of 1BOICz and mCPBC, with a mass ratio of 1BOICz to mCPBC of 20:80.

[0150] The molecular formula of 1BOICz is:

[0151]

[0152] Comparative Example 3

[0153] The only difference between this comparative example and Example 3 is that:

[0154] The luminescent material is composed of 1TICz, mCPBC, and DBN-ICz, with a mass ratio of 20:79:1.

[0155] Comparative Example 4

[0156] The only difference between this comparative example and Example 3 is that:

[0157] The luminescent material is composed of 1BOICz, mCPBC, and DBN-ICz, with a mass ratio of 20:79:1.

[0158] Relevant experimental and effect data:

[0159] The light-emitting devices obtained in Examples 1-6 and Comparative Examples 1-2 were encapsulated with UV-curable resin. The electroluminescence performance of the encapsulated devices was tested, mainly including the emission spectrum peak value (λEL), maximum power efficiency (PEmax), Von (turn-on voltage) / V, full width at half maximum (FWHM), maximum external quantum efficiency (EQEmax), and external quantum efficiency at 1000 nits (EQE). 1000 (CIE color coordinates). Specific test results are shown in Tables 1 and 2.

[0160] Devices <![CDATA[λ EL / nm]]> <![CDATA[V on / V]]> FWHM <![CDATA[EQE max ]]> <![CDATA[EQE 1000 ]]> <![CDATA[PE max (lm / W)]]> CIE(x,y) Comparative Example 1 504 3.1 100 26.1％ 24.9％ 71.7 (0.247,0.499) Comparative Example 2 534 3.0 101 34.6％ 33.8％ 95.5 (0.381,0.566) Example 1 528 3.0 91 40.4％ 40.3％ 122.4 (0.383,0.550) Example 2 530 3.0 94 36.4％ 36.1％ 110.5 (0.383,0.559) Example 3 528 3.0 93 37.7％ 36.5％ 115.6 (0.383,0.561)

[0161] Table 1

[0162] Devices <![CDATA[λ EL / nm]]> <![CDATA[V on / V]]> FWHM <![CDATA[EQE max ]]> PEmax (lm / W) Comparative Example 3 571 3.1 40 32.2％ 88 Comparative Example 4 551 3.1 35 36.6％ 99.3 Example 4 551 3.0 25 37.6％ 102.3 Example 5 551 3.0 28 36.8％ 100.8 Example 6 551 3.0 26 37.2％ 101.6

[0163] Table 2

[0164] As can be readily seen from Table 1, compared to Comparative Examples 1 and 2, the light-emitting devices of Examples 1-3 have a narrower FWHM, purer emission colors, and higher values ​​for EQEmax, EQE1000, and PEmax (lm / W). This indicates that the light-emitting devices of Examples 1-3 are more efficient than those of Comparative Examples 1-2. This demonstrates that the light-emitting materials used in Examples 1-3 have superior performance compared to Comparative Examples 1-2.

[0165] As can be readily seen from Table 2, the FWHM of the light-emitting devices in Examples 4-6 is significantly narrower than that in Comparative Examples 3-4. This indicates that the luminescent molecules selected in Examples 4-6, as sensitizers, can better purify the light color of the light-emitting devices compared to the sensitizers in Comparative Examples 3-4. Furthermore, Examples 4-6 exhibit higher EQEmax and PEmax (lm / W), indicating that the light-emitting devices in Examples 4-6 are more efficient than those in Comparative Examples 3-4. This demonstrates that the luminescent materials selected in Examples 4-6 have superior performance compared to those in Comparative Examples 3-4.

[0166] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0167] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to." Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. For associations involving three or more related objects described using "and / or", it indicates that any one of the three related objects can exist alone, or at least two of them can exist simultaneously. For example, for A, and / or B, and / or C, it can mean that any one of A, B, and C exists alone, or any two of them exist simultaneously, or all three of them exist simultaneously. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.

[0168] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A luminescent material, characterized in that, The luminescent material comprises a luminescent molecule formed by attaching an equivalent multiple resonance acceptor to a spatially relatively loose donor, the luminescent molecule having an ADA-type molecular configuration, and the luminescent molecule being selected from any one of the following molecules: 、 、 。 2. A light-emitting device, characterized in that, The light-emitting device comprises layers stacked together: anode; A light-emitting layer, wherein the light-emitting layer comprises the light-emitting material as described in claim 1; cathode.

3. A display device, characterized in that, The display device includes the light-emitting device as described in claim 2.

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