A TADF-sensitized organic electroluminescent device and a display device containing the same

Abstract

The present invention relates to the field of semiconductor technology, and more particularly, to a TADF-sensitized organic electroluminescent device and a display device comprising the same. The organic electroluminescent device sequentially comprises, from bottom to top: a substrate, a first electrode, an organic functional material layer, and a second electrode. The organic functional material layer sequentially comprises, from bottom to top: a hole transport region, a light-emitting layer, and an electron transport region. The light-emitting layer comprises a host material and a dopant material; the host material comprises one or more organic materials, the host material at least contains one spatial CT state TADF material, and the dopant material is a boron-containing compound. By selecting the host material of the light-emitting layer in the device and the combination between the host material and the dopant material of the light-emitting layer, the efficiency and service life of the organic electroluminescent device are improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly relates to a TADF-sensitized organic electroluminescent device and a display device including the device. Background Art

[0002] The technology of organic electroluminescent (OLED: Organic Light Emitting Diodes) devices can be used to manufacture new display products and new lighting products, and is expected to replace existing liquid crystal displays and fluorescent lamp lighting, with a very broad application prospect. Generally, an organic electroluminescent device composed of several layers includes an anode, a cathode, a hole injection layer, a hole transport layer, an organic light-emitting layer, an electron transport layer, and an electron injection layer. As a current device, when a voltage is applied to the two electrodes of the organic electroluminescent device, holes from the anode and electrons from the cathode are recombined in the organic light-emitting layer through the action of an electric field to form excitons, and the excitons relax to the ground state to release energy, thereby generating organic electroluminescence.

[0003] For traditional fluorescence emission, due to the limitation of electron spin forbidden, the theoretical internal quantum luminescence efficiency is only 25%, and the device efficiency far cannot meet the requirements in practical applications. For phosphorescent devices, due to the presence of heavy metal atoms, the spin forbidden limitation can be broken, and the theoretical internal quantum efficiency of the device can reach 100%. However, due to the presence of heavy metal atoms, its price is too high and the device life is relatively short.

[0004] In addition, the mechanism of triplet-triplet annihilation is applied in OLED devices, which can effectively solve the problems of high price and short life. However, in this mechanism, two triplet excitons are required to be converted into one singlet exciton, so the theoretical internal quantum efficiency is only 62.5%, and the device efficiency is still low. The sensitized fluorescence technology is considered to be the next-generation OLED technology. It can not only solve the problems of high material price and short device life, but also its theoretical internal quantum efficiency can reach 100%, which can greatly improve the device efficiency. However, due to the immaturity of the material system and the unreasonable matching between materials, the device performance is still at a relatively low level.

[0005] Therefore, the design of new functional materials and the reasonable matching of these materials in devices are of great significance for improving device performance and promoting the commercial application of OLEDs. Summary of the Invention

[0006] The purpose of the present invention is to provide a sensitized organic electroluminescent device having a high external quantum yield and a longer service life.

[0007] This purpose is achieved by a sensitized fluorescent organic electroluminescent device having the following composition

[0008] A TADF-sensitized organic electroluminescent device, wherein the organic electroluminescent device sequentially includes, from bottom to top: a substrate, a first electrode, an organic functional material layer, and a second electrode.

[0009] The organic functional material layer sequentially includes, from bottom to top: a hole transport region, a light-emitting layer, and an electron transport region;

[0010] The hole transport region sequentially includes, from bottom to top: a hole injection layer, a hole transport layer, and an electron blocking layer, and the hole injection layer contains a hole transport layer material and a P-type dopant;

[0011] The light-emitting layer includes a host material and a dopant material;

[0012] The host material includes one or more organic materials, the host material contains at least one spatial CT state TADF material, and the dopant material is a boron-containing compound.

[0013] Preferably, the reverse intersystem crossing rate (K RIST ) of the spatial CT state TADF material is not lower than 1×10 5 / s;

[0014] Preferably, the reverse intersystem crossing rate (K RIST ) of the spatial CT state TADF material is not lower than 1×10 6 / s.

[0015] Preferably, the HOMO energy level of the spatial CT state TADF material is greater than the HOMO energy level of the boron-containing compound, and the absolute value of the difference between the HOMO energy level of the spatial CT state TADF material and the HOMO energy level of the boron-containing compound is not greater than 0.2 eV; and / or the fluorescence emission spectrum of the spatial CT state TADF material overlaps with the ultraviolet-visible light absorption spectrum of the boron-containing compound.

[0016] Preferably, the triplet energy level of the spatial CT state TADF material is greater than the singlet energy level of the boron-containing compound, and the difference therebetween is not less than 0.15 eV.

[0017] Preferably, the overlap of the HOMO and LUMO distributions of the spatial CT state TADF material based on quantum chemical calculations is less than 20%, and the spatial CT state TADF material has a spatial bridging group, and the structure of the spatial CT state TADF material is shown in general formula (1)

[0018]

[0019] wherein Ar1 and Ar2 respectively select a D-type structure and an A-type structure, the D-type structure is shown in general formula (2), and the A-type structure is shown in the structure of general formula (3) or (4);

[0020] Any substitution site in the general formula (2) or general formula (4) can be connected to the general formula (1); any other site of L1 in the general formula (3) can be connected to the general formula (1);

[0021] X is represented as O, S or N-R a ; Z, Z1, Z2 each appear the same or differently as a nitrogen atom or C-R0; for example, in the general formula (1), Z can be N or C-R0 each time it appears, that is to say, Z in the general formula (1) can be the same or different.

[0022] R a , R0, Ar4 - Ar5 are the same or different and are represented as hydrogen, deuterium, tritium, substituted or unsubstituted C3 - C 10 cycloalkyl, substituted or unsubstituted C6 - C 30 aryl, substituted or unsubstituted C5 - C 30 heteroaryl; where adjacent R0 on the same aromatic ring can be connected to form a ring;

[0023] L, L1 are represented as a single bond, substituted or unsubstituted C6 - C 30 arylene, substituted or unsubstituted C5 - C 30 heteroarylene;

[0024] The heteroatoms in the substituted or unsubstituted C5 - C 30 heteroaryl or heteroarylene are selected from N, S or O;

[0025] The substituents in the aforementioned "substituted or unsubstituted" are optionally selected from one or more of deuterium, tritium, cyano, methyl, ethyl, propyl, isopropyl, tert - butyl, butyl, pentyl, hexyl, phenyl, naphthyl, naphthyridinyl, biphenyl, terphenyl, pyridyl.

[0026] Preferably, the boron - containing compound includes the general formula (5) and / or the general formula (6) and / or their polymers:

[0027]

[0028] In the general formula (5) and the general formula (6),

[0029] R1, R2, R3, R4, R5, R6, R7 are each independently represented as a hydrogen atom, a fluorine atom, C3 - C 10 cycloalkyl, C3 - C 10 heterocycloalkyl, C6 - C 60 aryl or C5 - C 60 heteroaryl; where the C3 - C 10 cycloalkyl, C3 - C 10 heterocycloalkyl, C6 - C60 An aryl or C5-C 60 heteroaryl is optionally substituted with the following substituents: deuterium, tritium, halogen, cyano, C1-C 10 alkyl, C1-C 10 alkoxy, C6-C 20 aryl or C5-C 20 heteroaryl; and R1, R2, and R3 do not simultaneously represent hydrogen atoms; R4, R5, R6, and R7 do not simultaneously represent hydrogen atoms.

[0030] Preferably, the boron-containing compound is selected from the general formula (7) and / or the general formula (8) and / or the general formula (9) and / or the general formula (10) and / or the general formula (11) and / or the general formula (12) and / or the general formula (13) and / or their polymers:

[0031]

[0032] In the general formula (7) and the general formula (8):

[0033] R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 , R 30 are each independently hydrogen, deuterium, protium, tritium, C6-C 30 aryl, C5-C 30 heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy, and at least one hydrogen in the aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy is optionally substituted with halogen, aryl, heteroaryl or alkyl; the aforementioned C6-C 30 aryl is preferably phenyl, naphthyl or anthryl; the aforementioned C5-C 30 heteroaryl is preferably carbazolyl; the aforementioned alkyl is preferably C1-C6 alkyl;

[0034] Or adjacent groups among R8 to R 18 are optionally bonded to each other and together with the a-ring, b-ring or c-ring form an aryl or heteroaryl ring; R23～25 and R 28～30 adjacent groups in are optionally bonded to each other and together with the g-ring and / or f-ring form an aryl or heteroaryl ring; wherein at least one hydrogen in the formed aryl or heteroaryl ring is optionally substituted by aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy; the aforementioned heteroaryl is preferably isoquinolyl; the aforementioned alkyl is preferably C1-C6 alkyl;

[0035] X1, X2, X3, X4, X5, X6 are each independently represented as O, S, Se, N-R or B-R, and the R is C6-C 12 aryl, C2-C 15 heteroaryl or C1-C6 alkyl, and at least one hydrogen in the C6-C 12 aryl or C2-C 15 heteroaryl is optionally substituted by C1-C6 alkyl; or the R is optionally bonded to the a-ring, b-ring or c-ring through -O-, -S-, -C(-Rg)2- or a single bond, and the Rg is selected from C1-C6 alkyl;

[0036] R 19 and R 20 are each independently hydrogen, C1-C6 alkyl or C6-C 12 aryl,

[0037] Z3 and Z4 are each independently aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, aryloxy, heteroaryloxy, arylthio or heteroarylthio, or at least one hydrogen in the above groups is optionally substituted by aryl, heteroaryl, alkyl or alkyl-substituted silyl, or Z3 is optionally bonded to the d-ring through -O-, -S-, -C(-Rb)2- or a single bond, or Z4 is optionally bonded to the e-ring through -O-, -S-, -C(-Rb)2- or a single bond, and the Rb of -C(-Rb)2- is hydrogen or C1-C6 alkyl;

[0038]

[0039] In the general formulas (9) and (10),

[0040] X7, X8, X9 are represented as O, S, Se, C-Rc, and the Rc of C-Rc is cyano, C6-C 30 aryl, C6-C 30 heteroaryl or C1-C6 alkyl, and the C6-C 30 aryl or C6-C 30The heteroaryl is optionally substituted with the following substituents: C1-C6 alkyl or C1-C6 alkoxy, and the substituent is preferably methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy;

[0041] R 31 、R 32 、R 33 、R 34 、R 35 、R 36 、R 37 、R 38 、R 39 、R 40 、R 41 、R 43 、R 44 、R 45 、R 46 、R 47 、R 48 、R 49 、R 50 、R 51 、R 52 、R 53 are each independently hydrogen, deuterium, protium, tritium, fluorine, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy, or at least one hydrogen in these groups is optionally substituted with aryl, heteroaryl, alkyl or alkoxy; the aforementioned alkyl is preferably methyl, ethyl, propyl, isopropyl, butyl, isobutyl or tert-butyl; the aforementioned alkoxy is preferably methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy or ethylhexoxy;

[0042] Or R 43 、R 44 、R 45 、R 46 Among them, two adjacent groups are optionally bonded to each other to form a ring, and the ring is preferably C6-C 30 aryl or C6-C 30 heteroaryl; or R 50 、R 51 、R 52 、R 53 Among them, two adjacent groups are optionally bonded to each other to form a ring, and the ring is preferably C6-C 30 aryl or C6-C 30 heteroaryl; the aforementioned C6-C 30 aryl is preferably phenyl; or the aforementioned C6-C 30 aryl or C6-C 30The heteroaryl is optionally substituted with the following substituents: C1-C6 alkyl or C1-C6 alkoxy. Preferably, the C1-C6 alkyl or C1-C6 alkoxy is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy;

[0043]

[0044] In the general formula (11), X 10 represents O, S, Se, N-Rd, and Rd of N-Rd is C6-C 12 aryl, C2-C 15 heteroaryl or C1-C6 alkyl,

[0045] R 54 、R 55 、R 56 、R 57 、R 58 、R 59 、R 60 、R 61 、R 62 、R 63 、R 64 、R 65 、R 66 are each independently hydrogen, fluorine, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy, or at least one hydrogen in the aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino is optionally substituted with aryl, heteroaryl or alkyl;

[0046] Or R 59 、R 60 、R 61 、R 62 in which two adjacent groups are optionally bonded to each other to form a ring, or R 63 、R 64 、R 65 、R 66 in which two adjacent groups are optionally bonded to each other to form a ring; the ring is preferably C6-C 30 aryl or C6-C 30 heteroaryl; or the C6-C 30 aryl or C6-C 30 heteroaryl is optionally substituted with the following substituents: phenyl, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy;

[0047]

[0048] In General Formulas (12) and (13),

[0049] X 11 and Y each independently represent -O-, -S-, or -N(Re)-, where the Re are the same or different and are each independently selected from a hydrogen atom, a cyano group, a C1-C 20 alkyl group, a C2-C 20 alkenyl group, a C6-C 30 aryl group, or a C2-C 30 heteroaryl group containing one or more heteroatoms;

[0050] or the Re bonds to the adjacent Z5 to form a ring, which is preferably a C6-C 30 aryl group or a C6-C 30 heteroaryl group;

[0051] Z5 are the same or different and are each independently selected from a nitrogen atom or a C-Rf;

[0052] The Rf represents a hydrogen atom, a deuterium atom, a tritium atom, a cyano group, a halogen, a C1-C 20 alkyl group, a C6-C 30 aryl group, or a C2-C 30 heteroaryl group containing one or more heteroatoms;

[0053] or Re and Rf optionally bond to each other to form a ring, which is preferably a C6-C 30 aryl group or a C6-C 30 heteroaryl group;

[0054] A represents C 14 -C 40 aryl group, a C2-C 30 heteroaryl group containing one or more heteroatoms;

[0055] or the above C1-C 20 alkyl group, a C2-C 20 alkenyl group, a C6-C 30 aryl group, a C2-C 30 heteroaryl group, a C6-C 30 heteroaryl group or C 14 -C 40 aryl group is optionally substituted with the following substituents: a deuterium atom, a tritium atom, a cyano group, a halogen atom, a C1-C 10 alkyl group, a C6-C 30 aryl group, a C2-C 30 heteroaryl group.

[0056] Preferably, the TADF material having a spatial CT state is selected from one or more of the following compounds:

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068] Preferably, the boron-containing compound is selected from at least one of the following compounds:

[0069]

[0070] Preferably, the weight ratio of the boron-containing compound / (boron-containing compound and host material) in the TADF-sensitized organic electroluminescent device is 0.1% to 10%.

[0071] A full-color display device including red, green, and blue pixels, wherein the pixel region of the full-color display device includes the sensitized organic electroluminescent device described above.

[0072] Beneficial effects

[0073] In the present invention, a thermally activated delayed fluorescence material (TADF material) having the characteristics of a spatial CT state is used as the sensitizing host material of a fluorescence sensitizing device, which has the characteristics of fast reverse intersystem crossing speed, high fluorescence quantum yield, and strong spectral stability.

[0074] The fast reverse intersystem crossing speed of the material can effectively increase the energy transfer efficiency between the host and the guest, and reduce the quenching caused by exciton aggregation; the high fluorescence quantum yield indicates that the exciton utilization rate of such materials is high, and the loss of luminescence energy is reduced; the spectral stability can ensure the stability of the energy transfer between the host and the guest materials. Therefore, from the perspective of the comprehensive performance of the device, it has the characteristics of high efficiency, small efficiency roll-off, and long life. In summary, the advantages of the organic electroluminescent device of the present invention lie in improving the luminous efficiency and service life of the device. Brief Description of the Drawings

[0075] Figure 1 Structural diagram of the organic electroluminescent device of the present invention.

[0076] Figure 1 In the figure, 1. Substrate; 2. First electrode; 3. Hole injection layer; 4. Hole transport layer; 5. Electron blocking layer; 6. Light-emitting layer; 7. Electron transport layer; 8. Electron injection layer; 9. Second electrode; A. Electron transport region; B. Hole transport region.

[0077] Figure 2 Fluorescence emission spectrum of the host material of the blue light-emitting device of the present invention and ultraviolet-visible absorption spectrum of the doping material. Among them, UV - ultraviolet-visible absorption spectrum, PL - fluorescence emission spectrum.

[0078] Figure 3 Fluorescence emission spectrum of the host material of the green light-emitting device of the present invention and ultraviolet-visible absorption spectrum of the doping material.

[0079] Figure 4 Fluorescence emission spectrum of the host material of the red light-emitting device of the present invention and ultraviolet-visible absorption spectrum of the doping material. Detailed Description of the Invention

[0080] Hereinafter, embodiments of the present invention will be described in detail. However, these embodiments are only exemplary, and the present invention is not limited thereto and is defined by the scope of the claims.

[0081] In the present invention, unless otherwise stated, all operations are carried out under room temperature and normal pressure conditions.

[0082] In the present invention, the "alkyl group" used refers to straight-chain and branched-chain alkyl groups having a specified number of carbon atoms, such as the number of 1 to 20 carbon atoms (C1-C 20 alkyl group), 1 to 10 carbon atoms (C1-C 10 alkyl group), 1 to 6 carbon atoms (C1-C6 alkyl group) or 1 to 4 carbon atoms (C1-C4 alkyl group). For example, C1-C6 alkyl group includes straight-chain and branched-chain alkyl groups having 1 to 6 carbon atoms. When referring to an alkyl residue having a specific number of carbons, it is intended to cover all branched-chain and straight-chain forms having that number of carbons; thus, for example, "butyl" means including n-butyl, sec-butyl, isobutyl and tert-butyl; "propyl" includes n-propyl and isopropyl. Alkylene is a subset of alkyl group, referring to a residue that is the same as the alkyl group but has two connection points.

[0083] In the present invention, the "alkenyl" used refers to an unsaturated branched or straight-chain alkyl group having at least one carbon-carbon double bond, which is obtained by removing one molecule of hydrogen from adjacent carbon atoms of the parent alkyl group. The group can be in the cis or trans configuration of the double bond. Typical alkenyl groups include, but are not limited to: vinyl; propenyl, such as prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl (allyl), prop-2-en-2-yl; butenyl, for example but-1-en-1-yl, but-1-en-2-yl, 2-methylprop-1-en-1-yl, but-2-en-1-yl, but-2-en-2-yl, buta-1,3-dien-1-yl, buta-1,3-dien-2-yl, and so on. In certain embodiments, the alkenyl group has 2 to 20 carbon atoms, while in other embodiments, it has 2 to 10, 2 to 8, or 2 to 6 carbon atoms. Alkenylene is a subset of alkenyl, referring to a residue that is the same as alkenyl but has two attachment points.

[0084] In the present invention, the "alkoxy" used refers to an alkyl group of a specified number of carbon atoms connected by an oxygen bridge. For example, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, pentyloxy, 2-pentyloxy, isopentyloxy, neopentyloxy, hexyloxy, 2-hexyloxy, 3-hexyloxy, 3-methylpentyloxy, etc. The alkoxy group generally has 1 to 10, 1 to 8, 1 to 6, or I to 4 carbon atoms connected by an oxygen bridge.

[0085] In the present invention, the "cycloalkyl" used refers to a structure formed by bonding two carbon atoms at both ends of a chain-shaped alkane with monovalent bonds, i.e., forming a cyclic structure. The cycloalkyl group is a monocyclic, bicyclic, tricyclic, or tetracyclic system, which may include fused-ring or bridged-ring systems. Examples thereof include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc.

[0086] The "heterocycloalkyl" in the present invention refers to a group in which one or more carbon atoms in the cycloalkyl group are replaced by other heteroatoms other than carbon atoms, such as N, O, S, Se, or B, etc.

[0087] In the present invention, the "aryl" used refers to a group derived from an aromatic monocyclic or polycyclic hydrocarbon ring system by removing a hydrogen atom from a ring carbon atom. The aromatic monocyclic or polycyclic hydrocarbon ring system contains only hydrogen atoms and carbon atoms, and at least one ring in the ring system is completely unsaturated, that is, it contains a cyclic, delocalized (4n + 2)π-electron system according to Hückel's theory. Examples thereof include, but are not limited to, phenyl, naphthyl, anthryl, phenanthryl, condensed tetraphenyl, pyrenyl, biphenyl, p-terphenyl, m-terphenyl, chrysenyl, meta-terphenyl, perylenyl, indenyl and other groups. Arylene is a subset of aryl, referring to a residue that is the same as aryl but has two attachment points. In certain embodiments, the aryl has 6 to 30 carbon atoms (C6-C30 aryl), or having 14 to 40 carbon atoms (C 14 -C 40 Arylene is a subset of aryl, referring to a residue that is the same as aryl but has two attachment points.

[0088] In the present invention, the "heteroaryl" used refers to an aryl containing at least one selected from nitrogen, oxygen or sulfur. Examples thereof include, but are not limited to, furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl, thiazolyl, oxadiazolyl, thiadiazolyl, pyridyl, pyrimidinyl, pyrazinyl, triazinyl, benzofuryl, benzothienyl, benzimidazolyl, indolyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, benzoxazinyl, benzothiazinyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl, fluorenyl, dibenzofuryl, dibenzothienyl, carbazolyl, and fused rings of combinations of the above groups. Any site of these groups can be used as a substitution site. In certain embodiments, the heteroaryl has 2 to 30 carbon atoms (C2-C 30 heteroaryl). Heteroarylene is a subset of heteroaryl, referring to a residue that is the same as heteroaryl but has two attachment points.

[0089] In the present invention, the "aryloxy" used refers to an aryl connected by an oxygen bridge, and the aryl has the above definition.

[0090] In the present invention, the "halogen" used refers to a chlorine atom, a fluorine atom or a bromine atom, etc.

[0091] In the present invention, the "diaryl amino", "diheteroaryl amino", and "aryl heteroaryl amino" respectively refer to an amino group substituted by two aryl groups, two heteroaryl groups, or one aryl group and one heteroaryl group, and the aryl group or heteroaryl group has the above definition.

[0092] In the present invention, unless otherwise specified, HOMO means the highest occupied molecular orbital, and LUMO means the lowest unoccupied molecular orbital. In addition, the "difference in HOMO energy level" and "difference in LUMO energy level" referred to in this specification mean the difference in each energy value. In addition, in the present invention, the HOMO and LUMO energy levels are represented by absolute values, and the comparison between energy levels is also a comparison of the magnitudes of their absolute values. Those skilled in the art know that the larger the absolute value of the energy level, the lower the energy of that energy level.

[0093] Any numerical range listed in this document is intended to include all sub-ranges with the same numerical precision within the listed range. For example, "1.0 to 10.0" means to include all sub-ranges between the listed minimum value of 1.0 and the listed maximum value of 10.0 (and including 1.0 and 10.0), that is, all sub-ranges with a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0. Any maximum numerical limit listed in this document is intended to include all smaller numerical limits incorporated herein, and any minimum numerical limit listed in this document is intended to include all larger numerical limits incorporated herein. Therefore, the applicant reserves the right to modify this specification, including the claims, to clearly describe any sub-range that falls within the range clearly described herein.

[0094] In the present invention, when describing electrodes, organic electroluminescent devices, and other structures, terms indicating orientation such as "upper", "lower", "top", and "bottom" only represent the orientation in a specific state, and do not mean that the relevant structures can only exist in the stated orientation; on the contrary, if the structure can be transformed in position, such as being inverted, the orientation of the structure is changed accordingly. Specifically, in the present invention, the "bottom" and "lower" sides of the electrode refer to the side of the electrode close to the substrate during the preparation process, and the opposite side away from the substrate is the "top" and "upper" sides.

[0095] The present invention provides a TADF-sensitized organic electroluminescent device, that is, a sensitized fluorescent organic electroluminescent device, which sequentially includes, from bottom to top: a substrate, a first electrode, an organic functional material layer, and a second electrode.

[0096] The organic functional material layer sequentially includes, from bottom to top: a hole transport region, a light-emitting layer, and an electron transport region.

[0097] The hole transport region sequentially includes, from bottom to top: a hole injection layer, a hole transport layer, and an electron blocking layer. The hole injection layer contains a hole transport layer material and a P-type dopant, and is preferably composed of a hole transport layer material and a P-type dopant.

[0098] The light-emitting layer includes a host material and a dopant material.

[0099] The host material can be composed of one or more organic materials. The host material contains at least one spatial CT state TADF material, and the dopant material is a boron-containing compound.

[0100] The overlap of the HOMO and LUMO distributions of the spatial CT state TADF material based on quantum chemical calculations is less than 20%, and it has a spatial bridging group. The structure of the spatial CT state TADF material is shown in general formula (1).

[0101]

[0102]

[0103] The above general formula (1) indicates that the substituents Ar1 and Ar2 can be respectively substituted on the rings on both sides of the general formula, or one of the substituents Ar1 and Ar2 substitutes X, and the other substituent substitutes Z on one of the rings on both sides of the general formula (1); however, Ar1 and Ar2 are not simultaneously substituted on the same ring; the slashes in the general formulas (2) to (4) represent single bonds, and any substitutable site on the general formula (2) can be used as the site for bonding with the general formula (1); the general formula (3) indicates that the general formula (1) can be bonded to L1 on the general formula (3); the general formula (4) indicates that any substitutable site on either of the left and right rings in the general formula (4) can be used as the site for bonding with the general formula (1).

[0104] The organic electroluminescent device of the present invention can be a bottom-emitting organic electroluminescent device, a top-emitting organic electroluminescent device, or a stacked organic electroluminescent device, and there is no specific limitation thereto.

[0105] Now, reference will be made to the attached Figure 1 , and the present invention will be further described in conjunction with specific embodiments.

[0106] Substrate

[0107] According to the present invention, for the substrate of the organic electroluminescent device, any substrate commonly used in organic electroluminescent devices can be used. Examples are transparent substrates such as glass or transparent plastic substrates; opaque substrates such as silicon substrates; and flexible PI film substrates. Different substrates have different mechanical strengths, thermal stabilities, transparencies, surface smoothness, and water resistances. Depending on the properties of the substrate, its usage directions are different. In the present invention, a transparent substrate is preferably used. The thickness of the substrate is not particularly limited.

[0108] First electrode

[0109] According to the present invention, a first electrode is formed on the substrate, and the first electrode and the second electrode can be opposite to each other. The first electrode can be an anode. The first electrode can be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the first electrode is a transmissive electrode, it can be formed using a transparent metal oxide, such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium tin zinc oxide (ITZO), etc. When the first electrode is a semi-transmissive electrode or a reflective electrode, it can include Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a metal mixture. The thickness of the first electrode layer depends on the material used and is generally 50 - 500 nm, preferably 70 - 300 nm, and more preferably 100 - 200 nm.

[0110] According to the present invention, the organic functional material layer disposed between the first electrode and the second electrode sequentially includes a hole transport region, a light-emitting layer, and an electron transport region from bottom to top.

[0111] Hole transport region

[0112] The hole transport region can be disposed between the first electrode and the light-emitting layer. The hole transport region can include a hole injection layer, a hole transport layer, and an electron blocking layer. For example, referring to Figure 1 , the hole transport region can include a hole injection layer, a hole transport layer, and an electron blocking layer sequentially disposed on the first electrode from bottom to top. Further, according to the device matching requirements, the hole transport layer between the electron blocking layer and the hole injection layer constituting the organic electroluminescent device can be a single film layer or a stacked structure of a plurality of various hole transport materials.

[0113] Hole injection layer and hole transport layer

[0114] In the present invention, the hole injection layer covering the anode surface is also called the anode interface buffer layer or the hole transport layer containing P-doping. No matter which name is used, this layer of film material has a basic feature, that is, it contains a host organic material that can conduct holes, and at the same time contains a P-type dopant with a relatively large HOMO energy level (the corresponding LUMO energy level will also be very large). In order to enable smooth injection of holes from the anode to the light-emitting layer, the HOMO energy level of the host organic material for conducting holes used in the hole injection layer must have certain characteristics with the P-type dopant, so as to be expected to achieve the occurrence of the charge transfer state between the host material and the dopant, achieve the ohmic contact between the hole injection layer and the anode, and achieve efficient injection from the electrode to the hole injection layer. This feature is summarized as: the difference between the HOMO energy level of the host organic material for conducting holes used in the hole injection layer and the LUMO energy level of the P-type dopant ≤ 0.4 eV. Therefore, for hole-type host materials with different HOMO energy levels, different P-type dopants need to be selected to match them in order to achieve ohmic contact at the interface and improve the hole injection effect.

[0115] In one embodiment of the present invention, in order to better inject holes, the hole injection layer further contains a P-type dopant with charge conductivity selected from the following: quinone derivatives such as tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinodimethane (F4-TCNQ); or hexaazatriphenylene derivatives such as 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN); or cyclopropane derivatives such as 4,4',4”-((1E,1'E,1”E)-cyclopropane-1,2,3-trimethylenetris(cyanomethylene))tris(2,3,5,6-tetrafluorobenzyl); or metal oxides such as tungsten oxide and molybdenum oxide, but not limited thereto. Preferably, the P-type dopant is selected from at least one of the following P1-P10:

[0116]

[0117] In the hole injection layer of the present invention, the ratio of the hole transport host material to the P-type dopant used is 99:1 - 95:5, preferably 99:1 - 97:3, by mass.

[0118] In an embodiment of the present invention, the materials of the hole injection layer and the hole transport layer are selected from the following materials,

[0119]

[0120] The above compounds are prepared or commercially available according to JP200056490A, JP2005263634A, JP2001316338A, CN105492574A, CN109314189A.

[0121] The thickness of the hole injection layer of the present invention can be 5 - 100 nm, preferably 5 - 50 nm and more preferably 5 - 20 nm, but the thickness is not limited to this range. The thickness of the hole transport layer of the present invention can be 5 - 200 nm, preferably 10 - 150 nm and more preferably 20 - 100 nm, but the thickness is not limited to this range.

[0122] Electron blocking layer

[0123] In the present invention, after forming a hole injection layer and a hole transport layer on the first electrode, an electron blocking layer for each light-emitting pixel unit (such as a blue, green, or red light-emitting pixel unit) is formed on the hole transport layer. In the present invention, since the spatial CT state TADF material has a carbazole or carbazole-fused ring group and its HOMO energy level is relatively deep, it is necessary to select an electron blocking layer material with a relatively deep HOMO energy level for device structure matching, which is more conducive to hole injection. At the same time, it is also required that the electron blocking layer material has a relatively high T1 energy level, which can avoid energy loss caused by exciton diffusion and help improve the efficiency of the device. Therefore, it is necessary to select a suitable electron blocking layer material to match the material of the light-emitting layer.

[0124] In the present invention, the electron blocking layer material is preferably selected from materials with a HOMO energy level greater than 5.6 eV and a triplet energy level higher than 2.6 eV.

[0125] In a preferred embodiment of the present invention, the electron blocking layer material of the sensitized fluorescent OLED device is selected from at least one of the following compounds:

[0126]

[0127] The above compounds are prepared or commercially available according to CN105061371B, CN108658953, and CN109053698A.

[0128] The thickness of the electron blocking layer in the present invention can be 1 - 200 nm, preferably 5 - 20 nm, but the thickness is not limited to this range.

[0129] Light-emitting layer

[0130] In the present invention, after forming the electron blocking layer, a corresponding light-emitting layer is formed on the electron blocking layer. The light-emitting layer of the sensitized fluorescent OLED device can be composed of a single, double, or triple organic material, and at least one of them contains the spatial CT state TADF material in the present invention, and the doping material is a boron-containing compound.

[0131] In the present invention, the host material can be composed of a single, double, or triple organic material. The triplet energy level (T1) of the first host material is higher than the singlet energy level (S1) of the second host, and the difference is greater than 0.15 eV, preferably greater than 0.2 eV. This can increase the intermolecular spacing between the second host material (also called the sensitizing material) and the doping material molecules, which is conducive to reducing or even preventing the exciton concentration quenching effect caused by the relatively high triplet exciton density of the second host material. At the same time, it is also conducive to reducing Dexter energy transfer and improving the utilization rate of excitons, thereby improving the efficiency of the device.

[0132] In the present invention, the spatial CT state thermally activated delayed fluorescence material (i.e., the TADF material in the CT state) is used as the sensitizing host material of the fluorescence sensitizing device, which has the characteristics of fast reverse intersystem crossing speed, high fluorescence quantum yield, and strong spectral stability, can more effectively utilize exciton energy, reduce exciton quenching, and improve the efficiency and stability of the device.

[0133] In the present invention, the TADF material in the spatial CT state is selected from at least one compound among H-1 to H-362:

[0134] In a preferred embodiment of the present invention, in addition to the spatial CT state TADF material, other host materials in the light-emitting layer can be selected from one or more of the following compounds:

[0135]

[0136] The above compounds are prepared or commercially available according to CN102870248A, CN105340101B, US20150001488A1, CN104488105A, CN105829320A.

[0137] In the present invention, the doping material is a boron-containing fluorescent material, which can be represented by general formula (5) or general formula (6) and their polymers:

[0138]

[0139] In general formula (5) and general formula (6),

[0140] R1, R2, R3, R4, R5, R6, R7 each independently represent a hydrogen atom, a fluorine atom, a C3-C 10 cycloalkyl group, a C3-C 10 heterocycloalkyl group, a C6-C 60 aryl group or a C5-C 60 heteroaryl group; wherein the C3-C 10 -cycloalkyl group, a C3-C 10 heterocycloalkyl group, a C6-C 60 aryl group or a C5-C 60 heteroaryl group is optionally substituted by the following substituents: deuterium, tritium, halogen, cyano group, a C1-C 10 alkyl group, a C1-C 10 alkoxy group, a C6-C 20 aryl group or a C5-C 20 heteroaryl group; and R1, R2, R3 do not simultaneously represent a hydrogen atom; R4, R5, R6, R7 do not simultaneously represent a hydrogen atom;

[0141] Preferably, the boron-containing compound is selected from the general formula (7) and / or the general formula (8) and / or the general formula (9) and / or the general formula (10) and / or the general formula (11) and / or the general formula (12) and / or the general formula (13) and / or their polymers:

[0142] In a preferred embodiment of the present invention, the doping material includes one or more compounds among DP-1 to DP-16:

[0143]

[0144]

[0145] The above compounds are prepared or commercially available according to CN106905367A, CN110612304A, CN110719914A, CN107501311A, US20200066997A1, CN107619418A, WO2020039930A1, WO2020039708A1.

[0146] In the present invention, the doping ratio of the doping material (boron-containing compound) is 0.1 to 10% by weight, based on the total mass of the host and the doping material in the light-emitting layer. This lower doping ratio can avoid Dexter energy transfer caused by too high a concentration of the doping material, resulting in energy loss, thereby improving the efficiency of the device.

[0147] Preferably, the doping material is selected from DP-1, DP-2, DP-6, DP-7.

[0148] In a more preferred embodiment of the present invention, the spatial CT state TADF material in the light-emitting layer is selected from any one of H-11, H-20, H-319, H-359 in combination with DP-2; any one of H-1, H-310, H-322, H-325, H362 in combination with DP-6; any one of H-82, H-208 in combination with DP-7; any one of H-180, H-207, H-230, H207, H-180 in combination with DP-1. Figure 2 are the fluorescence emission spectra of H-11, H-20, H-319 and the ultraviolet-visible absorption spectrum of the doping material DP-7, Figure 3 are the fluorescence emission spectra of H-1, H-82 and the ultraviolet-visible absorption spectrum of the doping material DP-6, Figure 4The fluorescence emission spectra of H-180 and H-207 and the ultraviolet-visible absorption spectrum of the doping material DP-1 are shown. The fluorescence emission spectra of the spatial CT state TADF materials and the ultraviolet-visible absorption spectra of the doping materials have good overlap, indicating good energy transfer effects between the host and the dopant. In the present invention, the preferred, more preferred, and most preferred compounds can be arbitrarily combined as needed and applied to the sensitized fluorescent OLED devices of the present invention.

[0149] When forming a full-color display device, during the vacuum deposition process, a shadow mask needs to be used to precisely prepare red (R), green (G), and blue (B) light-emitting layers at corresponding positions through the vacuum deposition process. However, when using the spin-coating process or laser-induced thermal imaging treatment, patterning does not need to be carried out through the shadow mask method.

[0150] The thicknesses of the red light-emitting layer, green light-emitting layer, and blue light-emitting layer can be adjusted to optimize the luminous efficiency and driving voltage. The preferred thickness range is 5 nm to 50 nm, but the thickness is not limited to this range.

[0151] Electron transport region

[0152] According to the present invention, the electron transport region may sequentially include, from bottom to top, a hole blocking layer, an electron transport layer, and an electron injection layer provided above the light-emitting layer, but is not limited thereto.

[0153] Electron transport layer

[0154] The electron transport layer may be provided above the light-emitting layer or (if present) the hole blocking layer. The electron transport layer material is a material that can easily receive electrons from the cathode and transfer the received electrons to the light-emitting layer. A material with a high electron mobility is preferred. As the electron transport layer of the organic electroluminescent device of the present invention, electron transport layer materials known in the prior art for organic electroluminescent devices can be used. For example, metal complexes of hydroxyquinoline derivatives represented by Alq3, BAlq, and Liq, various rare earth metal complexes, triazole derivatives, 2,4-bis(9,9-dimethyl-9H-fluoren-2-yl)-6-(naphthalen-2-yl)-1,3,5-triazine (CAS No.: 1459162-51-6) and other triazine derivatives, 2-(4-(9,10-bis(naphthalen-2-yl)anthracen-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole (CAS No.: 561064-11-7, commonly known as ET1) and other imidazole derivatives, oxadiazole derivatives, thiadiazole derivatives, carbodiimide derivatives, quinoxaline derivatives, phenanthroline derivatives, silicon-based compound derivatives, etc. The thickness of the electron transport layer of the present invention can be 10 - 80 nm, preferably 20 - 60 nm, and more preferably 25 - 45 nm, but the thickness is not limited to this range.

[0155] Electron injection layer

[0156] The electron injection layer can be disposed above the electron transport layer. The material of the electron injection layer is generally preferably a material with a low work function, so that electrons can be easily injected into the organic functional material layer. As the electron injection layer material of the organic electroluminescent device of the present invention, the electron injection layer materials known in the prior art for organic electroluminescent devices can be used. For example, lithium; lithium salts such as lithium 8-hydroxyquinoline, lithium fluoride, lithium carbonate or lithium azide; or cesium salts, cesium fluoride, cesium carbonate or cesium azide. The thickness of the electron injection layer of the present invention can be 0.1-5 nm, preferably 0.5-3 nm and more preferably 0.8-1.5 nm, but the thickness is not limited to this range.

[0157] Second electrode

[0158] The second electrode can be disposed above the electron transport region. The second electrode can be a cathode. The second electrode can be a transmissive electrode, a semi-transmissive electrode or a reflective electrode. When the second electrode is a transmissive electrode, the second electrode can include, for example, Li, Yb, Ca, LiF / Ca, LiF / Al, Al, Mg, BaF, Ba, Ag or a compound or mixture thereof; when the second electrode is a semi-transmissive electrode or a reflective electrode, the second electrode can include Ag, Mg, Yb, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti or a compound or mixture thereof.

[0159] Depending on the materials used, the full-color organic electroluminescent device of the present invention can be a top-emitting type, a bottom-emitting type or a double-sided emitting type.

[0160] In the case where the organic electroluminescent device is of the top-emitting type, the first electrode can be a reflective electrode, and the second electrode can be a transmissive electrode or a semi-transmissive electrode. In the case where the organic electroluminescent device is of the bottom-emitting type, the first electrode can be a transmissive electrode or a semi-transmissive electrode, and the second electrode can be a reflective electrode.

[0161] Due to the presence of the cathode and the anode, the electrodes of the OLED are not completely transparent. Therefore, the OLED device itself is a microcavity, which will affect the emitted light color and the light emission efficiency. The effect of the microcavity can be adjusted by the film thickness inside the device. The role of the microcavity adjustment layer or the optical adjustment layer is to adjust the emission color and the light emission efficiency.

[0162] In the process of manufacturing a full-color display device, for example, the organic electroluminescent device of the present invention can be manufactured by successively laminating a first electrode, an organic functional material layer, and a second electrode on a substrate. In this regard, physical vapor deposition methods such as sputtering or electron beam evaporation, or vacuum evaporation can be used, but are not limited thereto. Also, the above compounds can be used to form the organic functional material layer by, for example, vacuum deposition, vacuum evaporation, or solution coating. In this regard, solution coating means spin coating, dip coating, inkjet printing, screen printing, spraying, and roll coating, but is not limited thereto. Vacuum evaporation means heating a material and depositing it on a substrate in a vacuum environment. In the present invention, vacuum evaporation is preferably used to form each layer.

[0163] In addition, it should be noted that the materials used to form each layer in the present invention can be formed into a film alone and used as a single layer, or can be formed into a film after being mixed with other materials and used as a single layer, or can also be a stacked structure between layers formed into a film alone, a stacked structure between layers formed into a film after being mixed, or a stacked structure between a layer formed into a film alone and a layer formed into a film after being mixed.

[0164] It should be noted that exemplary embodiments have been disclosed herein. Although specific terms are used therein, these terms are used only and are interpreted only as general and descriptive meanings, and not for the purpose of limitation. Unless otherwise specified, the features, characteristics, and / or elements described in connection with a specific embodiment can be used alone or in combination with the features, characteristics, and / or elements described in connection with other embodiments.

[0165] Examples

[0166] The following examples are intended to better explain the present invention, but the scope of the present invention is not limited thereto.

[0167] To more clearly understand the present invention, the embodiments of the present invention only describe each pixel light-emitting unit. However, those skilled in the art should understand that the same hole injection layer and hole transport layer can be used when forming a full-color organic electroluminescent device for each pixel light-emitting unit.

[0168] All kinds of materials used in the examples and comparative examples are commercially available or can be obtained by methods known to those skilled in the art (for example, according to the methods in patents JP200056490A, JP2005263634A, JP2001316338A, CN105492574A, CN109314189A, CN105061371B, CN108658953, CN109053698A, CN102870248A, CN105340101B, US20150001488A1, CN104488105A, CN105829320A, CN106905367A, CN110612304A, CN110719914A, CN107501311A, US20200066997A1, CN107619418A, WO2020039930A1, WO2020039708A1).

[0169] I. Synthesis Example

[0170] Synthesis of Intermediate 2-1

[0171]

[0172] In a three-necked flask, under nitrogen protection, 0.01 mol of raw material A-1, 0.012 mol of raw material B-1, and 100 ml of toluene were added, stirred and mixed, then 0.0005 mol of Pd(PPh3)4, 0.015 mol of potassium carbonate, 10 ml of water, and a 1:1 mixture of ethanol were added. The mixture was stirred and heated to 110 °C, and refluxed for 24 hours; it was naturally cooled to room temperature, filtered, the filtrate was layered, the organic phase was taken and rotary evaporated under reduced pressure until there was no distillate, and passed through a neutral silica gel column to obtain Intermediate 1-1; elemental analysis structure (molecular formula C 30 H 18 ClNO): theoretical values C, 81.17; H, 4.09; Cl, 7.99; N, 3.16; measured values: C, 81.11; H, 4.12; Cl, 7.97; N, 3.18. LC-MS: measured value: 444.13 ([M+H]+); exact mass: 443.11.

[0173] In a three-necked flask, under nitrogen protection, weigh 0.005 mol of intermediate 1-1 and dissolve it in 100 ml of tetrahydrofuran. Cool it to -78 °C, then add 4 ml of a 1.6 mol / L solution of n-butyllithium in tetrahydrofuran to the reaction system. After reacting at -78 °C for 3 h, add 0.006 mol of triisopropyl borate and react for 2 h. Then raise the reaction system to 0 °C, add 8 ml of a 2 mol / L hydrochloric acid solution, stir for 3 h until the reaction is complete. Add ether for extraction, add anhydrous magnesium sulfate to the extract for drying, rotary evaporate, and pass through a neutral silica gel column to obtain the target product intermediate 2-1; elemental analysis structure (molecular formula C 30 H 20 BNO3): theoretical values C, 79.49; H, 4.45; N, 3.09; measured values: C, 79.41; H, 4.49; N, 3.12. LC-MS: measured value: 454.11 ([M+H]+); exact mass: 453.15.

[0174] Synthesis of intermediate 4-1

[0175]

[0176] In a three-necked flask, under nitrogen protection, add 0.01 mol of raw material A-1, 0.012 mol of raw material C-1, and 100 ml of toluene, stir and mix. Then add 0.0005 mol of Pd(PPh3)4, 0.015 mol of potassium carbonate, 10 ml of water and a 1:1 mixture of ethanol, stir and heat to 110 °C, and reflux for 24 hours; naturally cool to room temperature, filter, the filtrate is layered, take the organic phase and rotary evaporate under reduced pressure until there is no distillate, and pass through a neutral silica gel column to obtain intermediate 3-1; elemental analysis structure (molecular formula C 36 H 22 ClNO): theoretical values C, 83.15; H, 4.26; Cl, 6.82; N, 2.69; measured values: C, 83.18; H, 4.24; Cl, 6.84; N, 2.68. LC-MS: measured value: 520.22 ([M+H]+); exact mass: 519.14.

[0177] In a three-necked flask, under nitrogen protection, weigh 0.005 mol of intermediate 3-1 and dissolve it in 100 ml of tetrahydrofuran. Cool it to -78 °C, then add 4 ml of a 1.6 mol / L solution of n-butyllithium in tetrahydrofuran to the reaction system. After reacting at -78 °C for 3 h, add 0.006 mol of triisopropyl borate and react for 2 h. Then raise the reaction system to 0 °C, add 8 ml of a 2 mol / L hydrochloric acid solution, stir for 3 h until the reaction is complete. Add ether for extraction, add anhydrous magnesium sulfate to the extract for drying, rotary evaporate, and pass through a neutral silica gel column to obtain the target product intermediate 4-1; elemental analysis structure (molecular formula C 36 H24 BNO3): Theoretical values: C, 81.68; H, 4.57; N, 2.65; Measured values: C, 81.74; H, 4.54; N, 2.62. LC-MS: Measured value: 530.12 ([M+H]+); Accurate mass: 529.18.

[0178] Synthesis of Intermediate 5-1

[0179]

[0180] In a three-necked flask, under nitrogen protection, add 0.01 mol of raw material D-1, 0.012 mol of raw material E-1, 100 ml of toluene, stir and mix. Then add 0.0005 mol of Pd(PPh3)4, 0.015 mol of potassium carbonate, 10 ml of water and a 1:1 mixture of ethanol. Stir and heat to 110 °C, reflux for 24 hours; cool naturally to room temperature, filter, the filtrate is layered, take the organic phase and rotary evaporate under reduced pressure until there is no distillate, and pass through a neutral silica gel column to obtain Intermediate 5-1; Elemental analysis structure (molecular formula C 42 H 28 N2): Theoretical values: C, 89.97; H, 5.03; N, 5.00; Measured values: C, 89.91; H, 5.06; N, 5.03. LC-MS: Measured value: 561.31 ([M+H]+); Accurate mass: 560.23.

[0181] Synthesis of Intermediate 6-1

[0182]

[0183] In a three-necked flask, under nitrogen protection, add 0.01 mol of raw material F-1, 0.012 mol of raw material G-1, 100 ml of toluene, stir and mix. Then add 0.0005 mol of Pd(PPh3)4, 0.015 mol of potassium carbonate, 10 ml of water and a 1:1 mixture of ethanol. Stir and heat to 110 °C, reflux for 24 hours; cool naturally to room temperature, filter, the filtrate is layered, take the organic phase and rotary evaporate under reduced pressure until there is no distillate, and pass through a neutral silica gel column to obtain Intermediate 6-1; Elemental analysis structure (molecular formula C 36 H 23 BrN2): Theoretical values: C, 76.73; H, 4.11; N, 4.97; Measured values: C, 76.77; H, 4.14; N, 4.98. LC-MS: Measured value: 563.11 ([M+H]+); Accurate mass: 562.10.

[0184] Synthesis of Compound H-1

[0185]

[0186] In a three-necked flask, under nitrogen protection, 0.01 mol of intermediate 2-1, 0.012 mol of raw material F-1, and 100 ml of toluene were added, stirred and mixed, then 0.0005 mol of Pd(PPh3)4, 0.015 mol of potassium carbonate, 10 ml of water, and a 1:1 mixture of ethanol were added. The mixture was stirred and heated to 110 °C, and refluxed for 24 hours; it was naturally cooled to room temperature, filtered, the filtrate was layered, the organic phase was taken and rotary evaporated under reduced pressure until there was no distillate, and passed through a neutral silica gel column to obtain compound H-1; HPLC purity was 99.38%, and the yield was 69.9%; elemental analysis structure (molecular formula C 49 H 29 NO3): theoretical value C, 86.58; H, 4.30; N, 2.06; measured value: C, 86.44; H, 4.40; N, 2.01. LC-MS: measured value: 680.28 ([M+H]+); exact mass: 679.21.

[0187] Synthesis of compound H-20

[0188]

[0189] In a three-necked flask, under nitrogen protection, 0.01 mol of intermediate 4-1, 0.012 mol of raw material G-1, and 100 ml of toluene were added, stirred and mixed, then 0.0005 mol of Pd(PPh3)4, 0.015 mol of potassium carbonate, 10 ml of water, and a 1:1 mixture of ethanol were added. The mixture was stirred and heated to 110 °C, and refluxed for 24 hours; it was naturally cooled to room temperature, filtered, the filtrate was layered, the organic phase was taken and rotary evaporated under reduced pressure until there was no distillate, and passed through a neutral silica gel column to obtain compound H-20; HPLC purity was 99.44%, and the yield was 72.36%; elemental analysis structure (molecular formula C 55 H 33 NO3): theoretical value C, 87.40; H, 4.40; N, 1.85; measured value: C, 87.33; H, 4.46; N, 1.81. LC-MS: measured value: 756.30 ([M+H]+); exact mass: 755.25.

[0190] Synthesis of compound H-320

[0191]

[0192] In a three-necked flask, under nitrogen protection, add 0.01 mol of intermediate 5-1, 0.012 mol of raw material H-1, and 100 ml of toluene, stir and mix, then add 0.0005 mol of Pd(PPh3)4, 0.015 mol of potassium carbonate, 10 ml of water and a 1:1 mixture of ethanol, stir and heat to 110 °C, reflux for 24 hours; naturally cool to room temperature, filter, the filtrate is layered, take the organic phase and rotary evaporate under reduced pressure until there is no distillate, pass through a neutral silica gel column to obtain compound H-320; HPLC purity 99.64%, yield 70.37%; elemental analysis structure (molecular formula C 55 H 34 N2O2): theoretical value C, 87.51; H, 4.54; N, 3.71; measured value: C, 87.52; H, 4.51; N, 3.73. LC-MS: measured value: 755.30 ([M+H]+); exact mass: 754.26.

[0193] Synthesis of compound H-325

[0194]

[0195] In a three-necked flask, under nitrogen protection, weigh 0.005 mol of intermediate 6-1 and dissolve it in 100 ml of tetrahydrofuran, cool to -78 °C, then add 4 ml of a 1.6 mol / L solution of n-butyllithium in tetrahydrofuran to the reaction system, react at -78 °C for 3 h, then add 0.006 mol of triisopropyl borate, react for 2 h, then raise the reaction system to 0 °C, add 8 ml of 2 mol / L hydrochloric acid solution, stir for 3 h, the reaction is complete, add ether for extraction, the extract is dried with anhydrous magnesium sulfate, rotary evaporated, and passed through a neutral silica gel column to obtain the target product intermediate 7-1;

[0196] In a three-necked flask, under nitrogen protection, add 0.01 mol of intermediate 7-1, 0.012 mol of raw material I-1, and 100 ml of toluene, stir and mix, then add 0.0005 mol of Pd(PPh3)4, 0.015 mol of potassium carbonate, 10 ml of water and a 1:1 mixture of ethanol, stir and heat to 110 °C, reflux for 24 hours; naturally cool to room temperature, filter, the filtrate is layered, take the organic phase and rotary evaporate under reduced pressure until there is no distillate, pass through a neutral silica gel column to obtain compound H-325; HPLC purity 99.12%, yield 68.96%; elemental analysis structure (molecular formula C 51 H 33 N5): theoretical value C, 85.57; H, 4.65; N, 9.78; measured value: C, 85.53; H, 4.66; N, 9.79. LC-MS: measured value: 716.33 ([M+H]+); exact mass: 715.27.

[0197] The following compounds were prepared by a method similar to that of the material synthesis examples, where H-82, H-180, H-359, and H-362 were prepared according to the synthesis method of compound H-1, H-11, H-207, and H-208 were prepared according to the synthesis method of compound H-20, H-310 and H-322 were prepared according to the synthesis method of compound H-320, and H-319 was prepared according to the synthesis method of compound H-325. The synthetic raw materials used (all provided by ENN Energy & Chemicals Co., Ltd.) are shown in Table 1 below:

[0198] Table 1

[0199]

[0200]

[0201]

[0202] II. Property Testing of Materials

[0203] HOMO energy level: Measured by the IPS-3 measurement method. The specific measurement steps are as follows:

[0204] Using a vacuum evaporation device, under a pressure of 1.0E -5 Pa, control the evaporation rate to be Deposit the sample onto an ITO substrate with a film thickness of 60 - 80 nm; then use an IPS-3 measurement device to measure the HOMO energy level of the sample film. The measurement environment is a vacuum environment of 10 -2 Pa or less.

[0205] LUMO energy level: Calculated based on the difference between the HOMO energy level and the Eg energy level.

[0206] S1 and T1 energy levels:

[0207] S1 test: For a toluene solution of about 10 -5 M of the sample, at room temperature, select a Horiba Fluorolog-3 series fluorescence spectrometer to test and obtain a fluorescence spectrum. Select the starting peak position at the short wavelength to draw a tangent line, and the wavelength corresponding to the intersection of the tangent line and the extended baseline at the short wavelength is λS. The S1 value can be obtained through the formula S1 = 1240 / λS;

[0208] T1 test: For a toluene solution of about 10 -5 M of the sample, at 77K (liquid nitrogen), select a Horiba Fluorolog-3 series fluorescence spectrometer to test and obtain a phosphorescence spectrum. Select the starting peak position at the short wavelength to draw a tangent line, and the wavelength corresponding to the intersection of the tangent line and the extended baseline at the short wavelength is λT. The T1 value can be obtained through the formula T1 = 1240 / λT;

[0209] K RISC Test:

[0210] Sample preparation was carried out by vacuum evaporation. The sample was doped into mCP at a concentration of 30 wt%,

[0211]

[0212] The evaporation thickness was about 80 nm. After the sample preparation was completed, it was directly encapsulated with UV glue glass in a glove box filled with nitrogen; The fluorescence quantum yield was measured using a Fluorolog-3 series fluorescence spectrometer from Horiba In the transient fluorescence test, a NanoLED test module was selected to obtain the transient lifetime, delay lifetime, transient fluorescence ratio a, and delayed fluorescence ratio b. Through the formula the transient fluorescence quantum yield was obtained. Through the formula the delayed fluorescence quantum yield was obtained; K was derived through the following formula RISC :

[0213]

[0214] Table 1-1 shows the test results of each material.

[0215] Table 1-1

[0216]

[0217]

[0218]

[0219] As shown in Table 1-1, the reverse intersystem crossing rate (K RIST ) of the spatial CT state TADF material described in the present invention is higher than 1*10 5 / s, and the overlap of the HOMO and LUMO distributions is less than 20%.

[0220] II. Application Example - Organic Light-Emitting Device

[0221] 1. The molecular structural formulas of the related materials are as follows:

[0222]

[0223] Device Example 1: An organic light-emitting device was prepared according to the following steps:

[0224] (1) Use a transparent glass as the substrate, coat ITO with a thickness of 150 nm on it as the anode layer, ultrasonically clean it with deionized water, acetone, and ethanol for 15 minutes respectively, and then process it in a plasma cleaner for 2 minutes;

[0225] (2) On the washed anode layer, place the hole transport material HT-1 and the P-type dopant P1 in two evaporation sources respectively, and under a pressure of 1.0E -5 Pa, control the evaporation rate of HT-1 to be The evaporation rate of the P-type dopant is Co-evaporate them to form a hole injection layer with a thickness of 10 nm;

[0226] (3) On the hole injection layer, deposit a hole transport layer by vacuum evaporation. The thickness of the hole transport layer is HT-1, with a thickness of 60 nm;

[0227] (4) On the hole transport layer, form an electron blocking layer EB1 by vacuum evaporation, with a thickness of 10 nm;

[0228] (5) On the electron blocking layer, deposit the light-emitting layer materials, the first host material H1-4 and the second host material H-11, and the doping material is DP-2, with a mass ratio of 70:25:5, and a thickness of 40 nm;

[0229] (6) On the light-emitting layer, deposit ET1 and Liq by vacuum evaporation. The mass ratio of ET1 and Liq is 50:50, and the thickness is 40 nm. This layer serves as the electron transport layer;

[0230] (7) On the electron transport layer, deposit LiF by vacuum evaporation, with a thickness of 1 nm. This layer is the electron injection layer;

[0231] (8) Above the electron injection layer, vacuum deposit Al with a thickness of 80 nm. This layer is the cathode layer.

[0232] Device Example 2-29: Follow the steps of Example 1. The materials and experimental parameters used in each layer are as shown in Examples 2-29 in Table 2.

[0233] Device Comparative Examples 1-5: Follow the steps of Example 1. The materials and experimental parameters used in each layer are as shown in Comparative Examples 1-5 in Table 2. The specific structures of the above Device Examples 1-29 and Device Comparatives 1-5 are shown in Table 2.

[0234] Table 2

[0235]

[0236]

[0237]

[0238] After preparing the OLED light-emitting device as described above, the cathode and the anode are connected by a known driving circuit, and various performances of the device are measured. The measurement performance results of the devices of Examples 1-29 and Comparative Examples 1-5 are shown in Table 3.

[0239] Table 3

[0240]

[0241] The driving voltage, color coordinates (CIEx and CIEy), external quantum efficiency of the device, and full width at half maximum of the device are tested using an IVL (current-voltage-brightness) test system (Suzhou Fosida Scientific Instruments Co., Ltd.); LT90 refers to the time taken for the device brightness to decay to 90% of the original brightness; the lifetime test system is the EAS-62C type OLED lifetime test system of System Science Co., Ltd., Japan.

[0242] From the results in Table 3, it can be seen that compared with the comparative examples, the examples of the present invention have higher external quantum efficiency and longer service life. This indicates that by using the mixture of the host material and the doping material of the present invention as the light-emitting layer material, this combination advantageously improves the external quantum efficiency of the device and extends the service life of the device.

[0243] In order to compare the efficiency decay of different devices at different current densities, the efficiency decay coefficient is defined and represented. It represents the ratio of the difference between the efficiency of the device when the driving current is 10 mA / cm 2 and the maximum efficiency of the device to the maximum efficiency. The larger the value, the more serious the efficiency roll-off of the device. On the contrary, it indicates that the problem of rapid decay of the device at high current density has been controlled. The efficiency decay coefficients of the device examples 1-29 and the device comparative examples 1-5 are respectively measured, and the detection results are shown in Table 4:

[0244] Table 4

[0245]

[0246] From the data in Table 4, by comparing the efficiency decay coefficients of the examples and the comparative examples, it can be seen that the organic light-emitting device of the present invention can effectively reduce the efficiency roll-off.

[0247] Although the present invention has been described in connection with what are presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the described embodiments. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the foregoing embodiments are to be considered illustrative but not limiting of the invention in any way.

Claims

1. A TADF-sensitized organic electroluminescent device, characterized in that, The organic electroluminescent device sequentially includes, from bottom to top: a substrate, a first electrode, an organic functional material layer, and a second electrode. The organic functional material layer sequentially includes, from bottom to top: a hole transport region, a light-emitting layer, and an electron transport region. The hole transport region sequentially includes, from bottom to top: a hole injection layer, a hole transport layer, and an electron blocking layer. The hole injection layer contains a hole transport layer material and a P-type dopant. The light-emitting layer includes a host material and a dopant material. The host material includes one or more organic materials. The host material contains at least one spatial CT state TADF material. The dopant material is a boron-containing compound. The structure of the spatial CT state TADF material is shown in general formula (1): Wherein Ar1 and Ar2 respectively select a D-type structure and an A-type structure. The D-type structure is shown in general formula (2), and the A-type structure is shown in the structure of general formula (3) or (4). Any substitution site of general formula (2) or general formula (4) can be connected to general formula (1). Any other site of L1 in general formula (3) can be connected to general formula (1). X is represented as O or S. Z, Z1, and Z2 each appear the same or differently and are represented as a nitrogen atom or C-R0. R0 is hydrogen, deuterium, a substituted or unsubstituted C3-C 10 cycloalkyl, a substituted or unsubstituted C6-C 30 aryl, a substituted or unsubstituted C5-C 30 heteroaryl; Ar4 and Ar5, which are the same or different, represent a substituted or unsubstituted C6-C 30 aryl group, a substituted or unsubstituted C5-C 30 heteroaryl group; L and L1 each represent a single bond, a substituted or unsubstituted C6-C 30 arylene, a substituted or unsubstituted C5-C 30 heteroarylene; The heteroatom in the substituted or unsubstituted C5-C 30 heteroaryl or heteroarylene is selected from N, S or O; The substituents in the aforementioned "substituted or unsubstituted" are arbitrarily selected from one or more of deuterium, cyano group, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, butyl group, pentyl group, hexyl group, phenyl group, naphthyl group, naphthyridinyl group, biphenyl group, terphenyl group, pyridyl group.

2. The TADF-sensitized organic electroluminescent device according to claim 1, wherein The reverse intersystem crossing rate (K RIST ) of the spatial CT state TADF material is not less than 1×10 5 / s.

3. The TADF-sensitized organic electroluminescent device according to claim 1, wherein The reverse intersystem crossing rate (K RIST ) of the spatial CT state TADF material is not less than 1*10 6 / s.

4. The TADF-sensitized organic electroluminescent device according to claim 1, wherein The HOMO energy level of the spatial CT state TADF material is greater than the HOMO energy level of the boron-containing compound, and the absolute value of the difference between the HOMO energy level of the spatial CT state TADF material and the HOMO energy level of the boron-containing compound is not greater than 0.2 eV; and / or the fluorescence emission spectrum of the spatial CT state TADF material overlaps with the ultraviolet-visible light absorption spectrum of the boron-containing compound.

5. The TADF-sensitized organic electroluminescent device according to claim 1, wherein The triplet energy level of the spatial CT state TADF material is greater than the singlet energy level of the boron-containing compound, and the difference is not less than 0.15 eV.

6. The TADF-sensitized organic electroluminescent device according to claim 1, wherein The weight ratio of the boron-containing compound / (boron-containing compound and host material) is 0.1% - 10%.

7. The TADF-sensitized organic electroluminescent device according to claim 1, wherein The overlap of the HOMO and LUMO distributions of the spatial CT state TADF material based on quantum chemical calculations is less than 20%, and it has a spatial bridging group. The structure of the spatial CT state TADF material is shown in general formula (1). Wherein Ar1 and Ar2 respectively select a D-type structure and an A-type structure. The D-type structure is shown in general formula (2), and the A-type structure is shown in the structure of general formula (3) or (4). Any substitution site of general formula (2) or general formula (4) can be connected to general formula (1). Any other site of L1 in general formula (3) can be connected to general formula (1). X is represented as O or S. Z, Z1, and Z2 each appear the same or differently and are represented as a nitrogen atom or C-R0. R0 is hydrogen, deuterium, a substituted or unsubstituted C3-C 10 cycloalkyl, a substituted or unsubstituted C6-C 30 aryl, a substituted or unsubstituted C5-C 30 heteroaryl; Ar4 and Ar5, which are the same or different, represent a substituted or unsubstituted aryl group having 6 to C 30 and a substituted or unsubstituted heteroaryl group having 5 to C 30 ; L and L1 each represent a single bond, a substituted or unsubstituted C6-C 30 arylene, a substituted or unsubstituted C5-C 30 heteroarylene; The heteroatom in the substituted or unsubstituted C5-C 30 heteroaryl or heteroarylene is selected from N, S or O; The substituents in the aforementioned "substituted or unsubstituted" are arbitrarily selected from one or more of deuterium, tritium, cyano group, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, butyl group, pentyl group, hexyl group, phenyl group, naphthyl group, naphthyridinyl group, biphenyl group, terphenyl group, pyridyl group.

8. The TADF-sensitized organic electroluminescent device according to claim 1, wherein The boron-containing compound includes the general formula (5) and / or the general formula (6) and / or their polymers: In the general formula (5) and the general formula (6), R1, R2, R3, R4, R5, R6, and R7 each independently represent a hydrogen atom, a fluorine atom, a C3-C 10 cycloalkyl group, a C3-C 10 heterocycloalkyl group, a C6-C 60 aryl group, or a C5-C 60 heteroaryl group; wherein the C3-C 10 cycloalkyl group, the C3-C 10 heterocycloalkyl group, the C6-C 60 aryl group, or the C5-C 60 heteroaryl group is optionally substituted with the following substituents: deuterium, halogen, cyano, C1-C 10 alkyl group, C1-C 10 alkoxy group, C6-C 20 aryl group, or a C5-C 20 heteroaryl group; and R1, R2, and R3 do not simultaneously represent a hydrogen atom; R4, R5, R6, and R7 do not simultaneously represent a hydrogen atom.

9. The TADF-sensitized organic electroluminescent device according to claim 8, wherein wherein the boron-containing compound is selected from the general formula (7) and / or the general formula (8) and / or the general formula (9) and / or the general formula (10) and / or the general formula (11) and / or the general formula (12) and / or the general formula (13) and / or their polymers: In the general formula (7) and the general formula (8): R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 , R 30 are each independently hydrogen, deuterium, C6-C 30 aryl, C5-C 30 heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy, wherein at least one hydrogen in said aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy is optionally substituted by halogen, aryl, heteroaryl or alkyl; or R8 to R 18 adjacent groups in are optionally bonded to each other and together with the a-ring, b-ring or c-ring form an aryl or heteroaryl ring; R 23～25 and R 28～30 adjacent groups in are optionally bonded to each other and together with the g-ring and / or f-ring form an aryl or heteroaryl ring; wherein at least one hydrogen in the formed aryl or heteroaryl ring is optionally substituted with aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy; X1, X2, X3, X4, X5, and X6 are each independently represented by O, S, Se, N-R, or B-R, where R is C6-C 12 aryl, C2-C 15 heteroaryl, or C1-C6 alkyl, and at least one hydrogen in the C6-C 12 aryl or C2-C 15 heteroaryl is optionally substituted by C1-C6 alkyl; or R is optionally bonded to the a-ring, b-ring, or c-ring via -O-, -S-, -C(-Rg)2-, or a single bond, where Rg is selected from C1-C6 alkyl; R 19 and R 20 are each independently hydrogen, a C1-C6 alkyl group or a C6-C 12 aryl group Z3 and Z4 are each independently an aryl group, a heteroaryl group, a diarylamino group, a diheteroarylamino group, an arylheteroarylamino group, an alkyl group, a cycloalkyl group, an aryloxy group, a heteroaryloxy group, an arylthio group or a heteroarylthio group, or at least one hydrogen in the above groups is optionally substituted by an aryl group, a heteroaryl group, an alkyl group or an alkyl-substituted silyl group, or Z3 is optionally bonded to the d ring through -O-, -S-, -C(-Rb)2- or a single bond, or Z4 is optionally bonded to the e ring through -O-, -S-, -C(-Rb)2- or a single bond, and Rb in the -C(-Rb)2- is hydrogen or a C1-C6 alkyl group; In the general formula (9) and the general formula (10), X7, X8, X9 are represented by O, S, Se, C-Rc, where Rc of C-Rc is cyano, C6-C 30 aryl, C6-C 30 heteroaryl or C1-C6 alkyl, and the C6-C 30 aryl or C6-C 30 heteroaryl is optionally substituted by the following substituents: C1-C6 alkyl or C1-C6 alkoxy; R 31 、R 32 、R 33 、R 34 、R 35 、R 36 、R 37 、R 38 、R 39 、R 40 、R 41 、R 43 、R 44 、R 45 、R 46 、R 47 、R 48 、R 49 、R 50 、R 51 、R 52 、R 53 are each independently hydrogen, deuterium, fluorine, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy, or at least one hydrogen in these groups is optionally substituted by aryl, heteroaryl, alkyl or alkoxy; or R 43 、R 44 、R 45 、R 46 Any two adjacent groups in are optionally bonded to each other to form a C6-C 30 aryl or C6-C 30 heteroaryl; or R 50 、R 51 、R 52 、R 53 Any two adjacent groups in are optionally bonded to each other to form a C6-C 30 aryl or C6-C 30 heteroaryl; or the C6-C 30 aryl or C6-C 30 heteroaryl is optionally substituted with the following substituents: C1-C6 alkyl or C1-C6 alkoxy; In the general formula (11), X 10 is represented as O, S, Se, N-Rd, where Rd of N-Rd is C6-C 12 aryl, C2-C 15 heteroaryl or C1-C6 alkyl, R 54 、R 55 、R 56 、R 57 、R 58 、R 59 、R 60 、R 61 、R 62 、R 63 、R 64 、R 65 、R 66 are each independently hydrogen, fluorine, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy, or at least one hydrogen in said aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino is optionally substituted by aryl, heteroaryl or alkyl; or R 59 、R 60 、R 61 、R 62 any two adjacent groups among them are optionally bonded to each other to form a ring, or R 63 、R 64 、R 65 、R 66 any two adjacent groups among them are optionally bonded to each other to form a ring; the ring is a C6-C 30 aryl or a C6-C 30 heteroaryl; or the C6-C 30 aryl or the C6-C 30 heteroaryl is optionally substituted with the following substituents: phenyl, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy; In the general formula (12) and the general formula (13), X 11 and Y each independently represent -O-, -S- or -N(Re)-, where Re are the same or different and each independently selected from a hydrogen atom, a cyano group, a C1-C 20 alkyl group, a C2-C 20 alkenyl group, a C6-C 30 aryl group, or a C2-C containing one or more heteroatoms 30 heteroaryl group; Or the Re is linked to the adjacent Z5 key to form a ring, and the ring is C6-C 30 aryl or C6-C 30 heteroaryl; Z5 are the same or different and are each independently selected from a nitrogen atom or C-Rf; The Rf is represented by a hydrogen atom, a deuterium atom, a cyano group, a halogen, a C1-C 20 alkyl group, a C6-C 30 aryl group, or a C2-C containing one or more heteroatoms 30 heteroaryl group; Optionally, Re and Rf are bonded to each other to form a ring, which is a C6-C 30 aryl or C6-C 30 heteroaryl; A is represented as C 14 -C 40 aryl, C2-C containing one or more heteroatoms 30 heteroaryl; or the above C1-C 20 alkyl group, C2-C 20 alkenyl group, C6-C 30 aryl group, C2-C containing one or more heteroatoms 30 heteroaryl group, C6-C 30 heteroaryl group or C 14 -C 40 The aryl group is optionally substituted by the following substituents: deuterium atom, tritium atom, cyano group, halogen atom, C1-C 10 alkyl group, C6-C 30 aryl group, C2-C 30 heteroaryl group.

10. The TADF-sensitized organic electroluminescent device according to claim 9, wherein In the general formulas (7) and (8), the R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 、R 18 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 、R 29 、R 30 are each independently hydrogen, deuterium, a C6-C 30 aryl, a C5-C 30 heteroaryl, a diarylamino, a diheteroarylamino, an arylheteroarylamino, an alkyl, an alkoxy or an aryloxy, and at least one hydrogen in the C6-C 30 aryl, C5-C 30 heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy is optionally substituted by a halogen, an aryl, a heteroaryl or an alkyl; the aforementioned C6-C 30 aryl is phenyl, naphthyl or anthracenyl; the aforementioned C5-C 30 heteroaryl is carbazolyl; the aforementioned alkyl is a C1-C6 alkyl; Or R8 to R 18 adjacent groups in are optionally bonded to each other and together with the a-ring, b-ring or c-ring form an aryl or heteroaryl ring; R 23～25 and R 28～30 adjacent groups in are optionally bonded to each other and together with the g-ring and / or f-ring form an aryl or heteroaryl ring; wherein at least one hydrogen in the formed aryl or heteroaryl ring is optionally substituted by aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy; the aforementioned heteroaryl is isoquinolyl; the aforementioned alkyl is C1-C6 alkyl.

11. The TADF-sensitized organic electroluminescent device according to claim 9, wherein In the general formulas (9) and (10), X7, X8, and X9 represent O, S, Se, C-Rc, where Rc of C-Rc is cyano, C6-C 30 aryl, C6-C 30 heteroaryl or C1-C6 alkyl, and the C6-C 30 aryl or C6-C 30 heteroaryl is optionally substituted by the following substituents: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy; R 31 、R 32 、R 33 、R 34 、R 35 、R 36 、R 37 、R 38 、R 39 、R 40 、R 41 、R 43 、R 44 、R 45 、R 46 、R 47 、R 48 、R 49 、R 50 、R 51 B 52 、R 53 are each independently hydrogen, deuterium, fluorine, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy or aryloxy, or at least one hydrogen in these groups is optionally substituted by aryl, heteroaryl, alkyl or alkoxy; the aforementioned alkyl is methyl, ethyl, propyl, isopropyl, butyl, isobutyl or tert-butyl; the aforementioned alkoxy is methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy or 2-ethylhexyloxy; or R 43 、R 44 、R 45 、R 46 any two adjacent groups in are optionally bonded to each other to form a C6-C 30 aryl or a C6-C 30 heteroaryl; or R 50 、R 51 、R 52 、R 53 any two adjacent groups in are optionally bonded to each other to form a C6-C 30 aryl or a C6-C 30 heteroaryl; the C6-C 30 aryl or a C6-C 30 heteroaryl is optionally substituted with the following substituents: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy.

12. The TADF-sensitized organic electroluminescent device according to any one of claims 1-7, characterized in that, The TADF material having a spatial CT state is selected from one or more of the following compounds:

13. The TADF-sensitized organic electroluminescent device according to any one of claims 1-7, characterized in that, The boron-containing compound is selected from at least one of the following compounds:

14. A full-color display device including red, green, and blue pixels, characterized in that, The pixel region of the full-color display device includes the TADF-sensitized organic electroluminescent device according to any one of claims 1 to 13.

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