Organic electroluminescent diodes and display panels

Abstract

The present disclosure provides an organic electroluminescence diode and a display panel, and belongs to the technical field of display. The organic electroluminescence diode comprises an anode, a light-emitting layer, a hole blocking layer, an electron transport layer and a cathode which are sequentially stacked; wherein the light-emitting layer comprises a host material, a TADF material and a fluorescent dopant material; the host material is selected from a compound shown in chemical formula 1, and the material of the hole blocking layer and the material of the electron transport layer are selected from a compound shown in chemical formula 2. The organic electroluminescence diode can improve the service life of the organic electroluminescence diode.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and more specifically, to an organic light-emitting diode and a display panel. Background Technology

[0002] Superfluorescence technology based on TADF (thermally activated delayed fluorescence) sensitizers is considered one of the most valuable OLED (organic light-emitting diode) technologies. However, superfluorescent OLEDs typically face problems such as rapid device degradation and short lifetime.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide an organic light-emitting diode and a display panel to improve the lifespan of the organic light-emitting diode.

[0005] According to one aspect of this disclosure, an organic light-emitting diode is provided, comprising an anode, a light-emitting layer, a hole-blocking layer, an electron transport layer, and a cathode sequentially stacked; wherein the light-emitting layer comprises a host material, a TADF material, and a fluorescent doping material;

[0006] The main material is selected from the compound shown in chemical formula 1, and the material of the hole blocking layer is selected from the compound shown in chemical formula 2.

[0007]

[0008] Where m and n are the same or different, and each is independently selected from an integer not less than 1; k is 1 or 2;

[0009] L 1 Selected from aryl groups with 6 to 12 cyclic carbon atoms, whether single-bonded, substituted, or unsubstituted; when the L 1 When substituents are present, the substituents are selected from deuterium, fluorine, cyano, alkyl with 1 to 4 carbon atoms, deuterated alkyl with 1 to 4 carbon atoms, fluorinated alkyl with 1 to 4 carbon atoms, and aryl with 6 to 12 cyclic carbon atoms.

[0010] Ar 1 Selected from the groups shown in chemical formula 1-A, chemical formula 1-B, and chemical formula 1-C:

[0011]

[0012] Ring A, ring C, and ring E are each independently a substituted or unsubstituted benzene ring; when ring A, ring C, or ring E has a substituent, the substituent is selected from deuterium, fluorine, cyano, alkyl with 1 to 4 carbon atoms, deuterated alkyl with 1 to 4 carbon atoms, and fluorinated alkyl with 1 to 4 carbon atoms.

[0013] Ring B is Ring D is Z 1 and Z 2 Each independently selected from NR 1 O, S, C(R) 2 R 3 ), Si(R) 2 R 3 ), Ge(R) 2 R 3 ); where R 1 R 2 and R 3 They may be the same or different, and each is independently selected from hydrogen, alkyl groups having 1 to 4 carbon atoms, or aryl groups having 6 to 12 cyclic carbon atoms;

[0014] Ar 2 Selected from the groups shown in chemical formulas 1-D, 1-E, 1-F, and 1-G:

[0015]

[0016] Each R 4 They may be the same or different, and each is independently selected from hydrogen, deuterium, fluorine, cyano, alkyl with 1 to 4 carbon atoms, deuterated alkyl with 1 to 4 carbon atoms, fluorinated alkyl with 1 to 4 carbon atoms, aryl with 6 to 12 cyclic carbon atoms, and heteroaryl with 3 to 15 cyclic carbon atoms.

[0017] X and Y are each independently selected from NR 5 O, S, C(R) 6 R 7 ), Si(R) 6 R 7 ), Ge(R) 6 R 7 ); R 5 R 6 and R 7 Each element is independently selected from hydrogen, alkyl groups having 1 to 4 carbon atoms, or aryl groups having 6 to 12 cyclic carbon atoms; Y can also be selected from single bonds;

[0018] And Ar 1 and Ar 2 Not both are N-carbazolyl;

[0019] L2 Selected from aryl groups with 6 to 12 cyclic carbon atoms, whether single-bonded, substituted, or unsubstituted; when the L 2 When substituents are present, the substituents are selected from deuterium, fluorine, cyano, alkyl with 1 to 4 carbon atoms, deuterated alkyl with 1 to 4 carbon atoms, and fluorinated alkyl with 1 to 4 carbon atoms.

[0020] P 1 P 2 and P 3 They are either the same or different, and each is independently selected from N or CH, with at least two being N;

[0021] Ar 3 Selected from the groups shown in chemical formula 2-A and chemical formula 2-B:

[0022]

[0023] Ring F and ring G are each independently selected from benzene rings or pyridine rings, and at least one is a pyridine ring;

[0024] Q 1 Q 2 Each Q 3 Q 4 Q 5 They may be the same or different, and each is independently selected from hydrogen, deuterium, cyano, fluorine, substituted or unsubstituted aryl groups having 5 to 50 cyclic carbon atoms, or substituted or unsubstituted alkyl groups having 1 to 50 cyclic carbon atoms; or, Q 4 Q 5 Condensation forms a 5- to 7-membered ring with the attached group.

[0025] According to another aspect of this disclosure, a display panel is provided, including the aforementioned organic light-emitting diode.

[0026] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0028] Figure 1 This is a schematic diagram of the structure of an organic light-emitting diode in one embodiment of the present disclosure.

[0029] Figure 2This is a schematic diagram of the structure of a display panel in one embodiment of the present disclosure.

[0030] Figure 3 This is a schematic diagram of the structure of a display panel in one embodiment of the present disclosure.

[0031] Figure 4 This is a schematic diagram of the structure of a plurality of organic light-emitting diodes in a display panel according to one embodiment of the present disclosure. Detailed Implementation

[0032] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.

[0033] In this disclosure, the term "substituted or unsubstituted" means that the functional group described after the term may or may not have substituents (hereinafter, for ease of description, substituents are collectively referred to as Rc). For example, "substituted or unsubstituted aryl" refers to an aryl group having a substituent Rc or an unsubstituted aryl group. The substituent Rc mentioned above can be, for example, deuterium, halogen groups, cyano, alkyl, alkoxy, alkylthio, haloalkyl, deuteralkyl, cycloalkyl, trialkylsilyl, triphenylsilyl, diarylphosphine oxide, aryloxy, etc. In this disclosure, the "substituted" functional group can be substituted by one or more of the aforementioned substituents Rc.

[0034] In embodiments of this disclosure, the number of carbon atoms in substituted or unsubstituted groups refers to the total number of carbon atoms. For example, if Ar1 is a substituted aryl group with 12 carbon atoms, then the total number of carbon atoms in the aryl group and its substituents is 12.

[0035] The descriptive phrase "each...independently" used in the embodiments of this disclosure can mean that the specific options expressed by the same symbol in different groups do not affect each other, or it can mean that the specific options expressed by the same symbol in the same group do not affect each other. For example: in " In this context, each q is independently 0, 1, 2, or 3, and each R is independently selected from the descriptions of hydrogen, fluorine, and chlorine. The meaning is as follows: Formula Q-1 indicates that there are q substituents R on the benzene ring. Each R can be the same or different, and the options for each R do not affect each other. Formula Q-2 indicates that there are q substituents R on each benzene ring of biphenyl. The number q of substituents R on the two benzene rings can be the same or different, and each R can be the same or different. The options for each R do not affect each other.

[0036] In this disclosure, aryl refers to any optional functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group can be a monocyclic aryl (e.g., phenyl) or a polycyclic aryl; in other words, the aryl group can be a monocyclic aryl, a fused-ring aryl, two or more monocyclic aryl groups conjugated by carbon-carbon bonds, a monocyclic aryl and a fused-ring aryl group conjugated by carbon-carbon bonds, or two or more fused-ring aryl groups conjugated by carbon-carbon bonds. That is, two or more aromatic groups conjugated by carbon-carbon bonds can also be considered as aryl groups in this disclosure. Fused-ring aryl groups may include, for example, bicyclic fused aryl (e.g., naphthyl), tricyclic fused aryl (e.g., phenanthrene, fluorenyl, anthracene), etc. The aryl group does not contain heteroatoms such as B, N, O, S, Se, Si, or P. For example, in this disclosure, biphenyl, terphenyl, etc., are aryl groups. Examples of aryl groups may include phenyl, naphthyl, fluorenyl, anthracene, phenanthryl, biphenyl, terphenyl, tetraphenyl, benzo[9,10]phenanthryl, pyrene, benzofluoranthracene, etc. Indene, etc., but not limited to these.

[0037] In embodiments of this disclosure, the substituted aryl group may be one or more hydrogen atoms of the aryl group that are replaced by groups such as deuterium atoms, halogen groups, -CN, aryl, heteroaryl, trialkylsilyl, alkyl, cycloalkyl, alkoxy, alkylthioyl, etc. Specific examples of heteroaryl-substituted aryl groups include, but are not limited to, dibenzofuranyl-substituted phenyl, dibenzothiopheneyl-substituted phenyl, pyridyl-substituted phenyl, carbazoleyl-substituted phenyl, etc. It should be understood that the number of carbon atoms in the substituted aryl group refers to the total number of carbon atoms of the aryl group and the substituents on the aryl group. For example, a substituted aryl group with 18 carbon atoms means that the total number of carbon atoms of the aryl group and the substituents is 18.

[0038] In embodiments of this disclosure, a heteroaryl group refers to a monovalent aromatic ring or its derivative containing at least one heteroatom, where the heteroatom can be at least one of B, O, N, P, Si, Se, and S. The heteroaryl group can be a monocyclic or polycyclic heteroaryl group; in other words, it can be a single aromatic ring system or a system of multiple aromatic rings conjugated by carbon-carbon bonds, and any aromatic ring system can be a single aromatic monocyclic ring or a fused aromatic ring. For example, heteroaryl groups may include thiophene, furanyl, pyrrole, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridinel, pyridazinyl, pyrazinyl, quinolinyl, quinazolinyl, quinoxolinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, isoquinolinyl, indolyl, carbazole, benzoxazolyl, and benzimidazole. The group includes, but is not limited to, benzothiazolyl, benzocarbazolyl, benzothiophenel, dibenzothiophenel, thienozothiophenel, benzofuranyl, phenanthrolinel, isoxazolyl, thiadiazolyl, benzothiazolyl, phenothiazinyl, silanyl, dibenzofuranyl, and N-arylcarbazolyl (such as N-phenylcarbazolyl), N-heteroarylcarbazolyl (such as N-pyridylcarbazolyl), and N-alkylcarbazolyl (such as N-methylcarbazolyl), etc. Among these, thiophenel, furanyl, and phenanthrolinel are heteroaryl groups of the single aromatic ring type, while N-arylcarbazolyl and N-heteroarylcarbazolyl are heteroaryl groups of the polycyclic system type linked by carbon-carbon conjugation.

[0039] In embodiments of this disclosure, the substituted heteroaryl group may be one or more hydrogen atoms of the heteroaryl group that are replaced by groups such as deuterium atoms, halogen groups, -CN, aryl, heteroaryl, trialkylsilyl, alkyl, cycloalkyl, alkoxy, alkylthioyl, etc. Specific examples of aryl-substituted heteroaryl groups include, but are not limited to, phenyl-substituted dibenzofuranyl, phenyl-substituted dibenzothiophenyl, phenyl-substituted pyridyl, etc. It should be understood that the number of carbon atoms in the substituted heteroaryl group refers to the total number of carbon atoms of the heteroaryl group and the substituents on the heteroaryl group.

[0040] In this embodiment of the disclosure, a non-positioned connecting key refers to a single bond extending from the ring system. This means that one end of the linking bond can connect to any position in the ring system that the bond passes through, and the other end connects to the rest of the compound molecule.

[0041] For example, as shown in equation (f) below, the naphthyl group represented by equation (f) is connected to other positions in the molecule through two non-positional linkages that span the bicyclic ring. This means that any possible connection mode is shown in equations (f-1) to (f-10).

[0042]

[0043] For another example, as shown in equation (X'), the phenanthrene group represented by equation (X') is connected to other positions in the molecule via a non-positional linker extending from the middle of one side of the benzene ring. This means that any possible connection mode shown in equations (X'-1) to (X'-4) is included.

[0044]

[0045] In the embodiments of this disclosure, a non-positional substituent refers to a substituent connected by a single bond extending from the center of the ring system, indicating that the substituent can be attached to any possible position in the ring system. For example, as shown in the following formula (Y), the substituent R' group represented by formula (Y) is connected to the quinoline ring by a non-positional linking bond, which means that it includes any possible connection mode shown in formulas (Y-1) to (Y-7).

[0046]

[0047] This disclosure provides an organic light-emitting diode (OLED), see [link to relevant documentation]. Figure 1 The organic light-emitting diode (OLED) comprises an anode (AN), a light-emitting layer (EML), a hole-blocking layer (HBL), an electron transport layer (ETL), and a cathode (CATH) stacked sequentially. The EML comprises a host material, a thermally active delayed fluorescence (TADF) material, and a fluorescent dopant material. The host material is responsible for transporting charge carriers, such as at least one of electrons and holes. In embodiments of this disclosure, the host material is a hole-biased host material, meaning its hole mobility is greater than its electron mobility. Through transport by the host material, electrons and holes injected into the light-emitting layer primarily recombine on the TADF material (as an auxiliary material). The TADF material transfers the energy (excitons) generated by recombination to the fluorescent dopant material, causing the fluorescent dopant material to emit fluorescence.

[0048] In this embodiment, the host material is selected from compounds represented by chemical formula 1, and the hole-blocking layer material is selected from compounds represented by chemical formula 2.

[0049]

[0050] Where m and n are the same or different, and each is independently selected from an integer not less than 1; k is 1 or 2;

[0051] L 1 Selected from aryl groups with 6 to 12 cyclic carbon atoms, whether single-bonded, substituted, or unsubstituted; when the L 1When substituents are present, the substituents are selected from deuterium, fluorine, cyano, alkyl with 1 to 4 carbon atoms, deuterated alkyl with 1 to 4 carbon atoms, fluorinated alkyl with 1 to 4 carbon atoms, and aryl with 6 to 12 cyclic carbon atoms.

[0052] Ar 1 Selected from the groups shown in chemical formula 1-A, chemical formula 1-B, and chemical formula 1-C:

[0053]

[0054] Ring A, ring C, and ring E are each independently a substituted or unsubstituted benzene ring; when ring A, ring C, or ring E has a substituent, the substituent is selected from deuterium, fluorine, cyano, alkyl with 1 to 4 carbon atoms, deuterated alkyl with 1 to 4 carbon atoms, and fluorinated alkyl with 1 to 4 carbon atoms.

[0055] Ring B is Ring D is Z 1 and Z 2 Each independently selected from NR 1 O, S, C(R) 2 R 3 ), Si(R) 2 R 3 ), Ge(R) 2 R 3 ); where R 1 R 2 and R 3 They may be the same or different, and each is independently selected from hydrogen, alkyl groups having 1 to 4 carbon atoms, or aryl groups having 6 to 12 cyclic carbon atoms;

[0056] Ar 2 Selected from the groups shown in chemical formulas 1-D, 1-E, 1-F, and 1-G:

[0057]

[0058]

[0059] Each R 4 They may be the same or different, and each is independently selected from hydrogen, deuterium, fluorine, cyano, alkyl with 1 to 4 carbon atoms, deuterated alkyl with 1 to 4 carbon atoms, fluorinated alkyl with 1 to 4 carbon atoms, aryl with 6 to 12 cyclic carbon atoms, and heteroaryl with 3 to 15 cyclic carbon atoms.

[0060] X and Y are each independently selected from NR 5 O, S, C(R) 6 R 7 ), Si(R)6 R 7 ), Ge(R) 6 R 7 ); R 5 R 6 and R 7 Each element is independently selected from hydrogen, alkyl groups having 1 to 4 carbon atoms, or aryl groups having 6 to 12 cyclic carbon atoms; Y can also be selected from single bonds;

[0061] And Ar 1 and Ar 2 It may be either a substituted or unsubstituted N-carbazolyl group;

[0062] L 2 Selected from aryl groups with 6 to 12 cyclic carbon atoms, whether single-bonded, substituted, or unsubstituted; when the L 2 When substituents are present, the substituents are selected from deuterium, fluorine, cyano, alkyl with 1 to 4 carbon atoms, deuterated alkyl with 1 to 4 carbon atoms, and fluorinated alkyl with 1 to 4 carbon atoms.

[0063] P 1 P 2 and P 3 They are either the same or different, and each is independently selected from N or CH, with at least two being N;

[0064] Ar 3 Selected from the groups shown in chemical formula 2-A and chemical formula 2-B:

[0065]

[0066] Ring F and ring G are each independently selected from benzene rings or pyridine rings, and at least one is a pyridine ring;

[0067] Q 1 Q 2 Each Q 3 Q 4 Q 5 They may be the same or different, and each is independently selected from hydrogen, deuterium, cyano, fluorine, substituted or unsubstituted aryl groups having 5 to 50 cyclic carbon atoms, or substituted or unsubstituted alkyl groups having 1 to 50 cyclic carbon atoms; or, Q 4 Q 5 Condensation forms a 5- to 7-membered ring with the attached group.

[0068] In one embodiment of this disclosure, the material of the electron transport layer is also selected from the compound represented by chemical formula 2.

[0069] In one embodiment of this disclosure, both m and n are 1.

[0070] In one embodiment of this disclosure, L1 Selected from phenyl and biphenyl.

[0071] In one embodiment of this disclosure, Z 1 and Z 2 Each is independently selected from NH, O, S or CH2.

[0072] In one embodiment of this disclosure, rings A, C, and E are free of substituents.

[0073] In one embodiment of this disclosure, the group represented by chemical formula 1-B is selected from the following groups:

[0074]

[0075] The group represented by chemical formula 1-C is selected from the following groups:

[0076]

[0077]

[0078] In one embodiment of this disclosure, Ar 1 Selected from the following groups:

[0079]

[0080] In one embodiment of this disclosure, R 4 It is hydrogen.

[0081] In one embodiment of this disclosure, X is not selected from NR. 5 .

[0082] In one embodiment of this disclosure, X is selected from S, O, CMe2, and CPh2.

[0083] In one embodiment of this disclosure, Y is selected from single bonds, S, O, CMe2, and CPh2.

[0084] In one embodiment of this disclosure, R 5 R 6 R 7 Each is independently selected from hydrogen, methyl, and phenyl.

[0085] In one embodiment of this disclosure, Ar 2 Selected from the following groups:

[0086]

[0087] In one embodiment of this disclosure, the compound represented by Formula 1 is selected from the following compounds:

[0088]

[0089]

[0090] In one embodiment of this disclosure, Q 1 Q 2 They may be the same or different, and each is independently selected from hydrogen, deuterium, cyano, fluorine, or aryl groups with 6 to 12 cyclic carbon atoms.

[0091] Furthermore, Q 1 Q 2 They may be the same or different, and each is independently selected from phenyl or biphenyl.

[0092] In one embodiment of this disclosure, L 2 Selected from single bonds, phenyl, and biphenyl.

[0093] In one embodiment of this disclosure, each Q 3 They may be the same or different, and each may be independently selected from hydrogen, deuterium, cyano, fluorine, aryl with 6 to 12 carbon atoms in the cyclic group, and alkyl with 1 to 4 carbon atoms, for example selected from hydrogen, deuterium, phenyl, methyl, etc., especially selected from hydrogen.

[0094] In one embodiment of this disclosure, Q 4 Q 5 They may be the same or different, and each is independently selected from hydrogen, deuterium, cyano, fluorine, aryl with 6 to 12 cyclic carbon atoms, and alkyl with 1 to 4 carbon atoms, such as hydrogen, deuterium, phenyl, methyl, etc.

[0095] In one embodiment of this disclosure, Q 4 Q 5 Condensation forms a 5- to 7-membered ring with the attached group, such as a furan ring, pyrrole ring, thiophene ring, or cyclopentadiene ring. The formed 5- to 7-membered ring can be further substituted; for example, the methylene group of the cyclopentadiene ring can be replaced by two methyl groups or two phenyl groups, or a diphenylfluorene group can be screwed onto the methylene group of the cyclopentadiene ring.

[0096] In one embodiment of this disclosure, one of ring F and ring G is a benzene ring and the other is a pyridine ring.

[0097] In one embodiment of this disclosure, when Q 4 Q 5 When condensation occurs to form a 5- to 7-membered ring with the attached group, the group represented by chemical formula 2-A is selected from the following groups:

[0098]

[0099]

[0100] The group represented by chemical formula 2-B is selected from the following groups:

[0101]

[0102] Among them, W 1 Selected from NR 8 O, S; R 8 It is selected from hydrogen, alkyl groups having 1 to 4 carbon atoms, or aryl groups having 6 to 12 cyclic carbon atoms;

[0103] W 2 Selected from NR 9 O, S, C(R) 10 R 11 ), Si(R) 10 R 11 ), Ge(R) 10 R 11 ); R 9 Selected from hydrogen, alkyl groups having 1 to 4 carbon atoms, or aryl groups having 6 to 12 cyclic carbon atoms; R 10 and R 11 Each is independently selected from aryl groups having 6 to 12 carbon atoms in the cyclic formation;

[0104] W 3 Selected from C, Si, and Ge;

[0105] Each Q 6 They may be the same or different, and each is independently selected from hydrogen, deuterium, cyano, fluorine, substituted or unsubstituted aryl groups having 5 to 50 cyclic carbon atoms, or substituted or unsubstituted alkyl groups having 1 to 50 cyclic carbon atoms.

[0106] In one embodiment of this disclosure, R 8 It is hydrogen.

[0107] In one embodiment of this disclosure, W 3 Selected from C.

[0108] In one embodiment of this disclosure, Ar 3 Selected from the following groups:

[0109]

[0110] In one embodiment of this disclosure, the compound represented by chemical formula 2 is selected from the following compounds:

[0111]

[0112]

[0113]

[0114] In the organic light-emitting diode (OLED) disclosed herein, the host material of the light-emitting layer is a hole-prone host material with a hole mobility greater than an electron mobility. This allows the electron-hole recombination site to shift towards the cathode side. The host material is selected from the compound shown in Formula 1, and therefore possesses a high triplet (T1) energy. Based on this, the hole-blocking layer material of the OLED in this embodiment is selected from the compound shown in Formula 2, so that the hole-blocking layer material also possesses a high triplet energy, thereby achieving exciton blocking, preventing or reducing exciton leakage from the light-emitting layer to the hole-blocking layer, ensuring exciton utilization, and thus ensuring high luminous efficiency. Furthermore, electrons and holes mainly recombine on the TADF material, which allows the recombinated excitons to quickly transfer to the fluorescent dopant residue for luminescence, avoiding exciton accumulation and material aging.

[0115] Furthermore, by selecting compounds of Formula 1 as the host material and compounds of Formula 2 as the hole-blocking layer material, the hole-blocking layer material can possess a deeper HOMO energy level, thereby effectively blocking holes and reducing the amount of holes transported from the emitting layer to the hole-blocking layer. This confines the electron-hole recombination sites within the emitting layer, thereby reducing exciton loss and ensuring high luminous efficiency. Moreover, the hole-blocking layer also protects the film material between the hole-blocking layer and the cathode by blocking holes, preventing these film materials from aging prematurely under the impact of holes.

[0116] Furthermore, by selecting the host material from compounds of Formula 1 and the hole-blocking layer from compounds of Formula 2, the LUMO energy level difference between the host material and the hole-blocking layer can be minimized, thereby facilitating electron injection from the hole-blocking layer into the emissive layer. This prevents electrons from accumulating in the electron transport layer and hole-blocking layer, which would otherwise accelerate material aging.

[0117] As can be seen from the above, in the embodiments of this disclosure, by selecting the host material from compounds of Formula 1 and the hole blocking layer material from compounds of Formula 2, the electron-hole recombination site can be shifted towards the hole blocking layer side; the hole blocking layer material has a high triplet energy level to block exciton loss; the hole blocking layer has a deep HOMO energy level to block holes; the LUMO energy level between the host material and the hole blocking layer material is small to facilitate electron injection; and the electron transport layer has a fast electron mobility and matches the HOMO energy level of the hole blocking layer. Through these characteristics, electron-hole recombination in the luminescent layer can be achieved efficiently, and the diffusion loss of holes and excitons can be reduced, thus ensuring luminescence efficiency. While ensuring high luminous efficiency, the organic light-emitting diode of the present invention can also reduce the aging rate of materials by preventing excitons and holes from diffusing into the hole blocking layer and electron transport layer, and by preventing electrons from accumulating in the hole blocking layer and electron transport layer, thereby improving the lifespan of the organic light-emitting diode, effectively reducing the driving voltage, and improving the exciton recombination region in the light-emitting layer to a certain extent.

[0118] Furthermore, in the organic light-emitting diode of this embodiment, the light-emitting layer also includes a TADF material and a fluorescent dopant material. Since the host material has a high triplet energy level, exciton backflow on the TADF material can be reduced or avoided. The TADF material can rapidly convert triplet excitons to singlet excitons and transfer the singlet excitons to the fluorescent dopant material, enabling the fluorescent dopant material to quickly release energy through fluorescence. Thus, in the OLED of this embodiment, energy can be rapidly converted, transferred, and released, avoiding material aging caused by energy accumulation and improving the lifetime of the organic light-emitting diode.

[0119] In one embodiment, the fluorescent doping material is a fluorescent material containing boron.

[0120] In one embodiment of this disclosure, the content of the host material (the proportion of the evaporation rate component of the host material in the co-evaporation rate) in the light-emitting layer is not less than 50%.

[0121] In one embodiment of this disclosure, the content of fluorescent dopant material in the light-emitting layer (the percentage of the fluorescent dopant material's deposition rate component in the co-evaporation rate) is no more than 5% to avoid fluorescence quenching. Further, the content of fluorescent dopant material in the light-emitting layer (the percentage of the fluorescent dopant material's deposition rate component in the co-evaporation rate) is greater than 0.5%.

[0122] In one embodiment of this disclosure, the rate at which TADF material transfers excitons to the fluorescent doping material is greater than the quenching rate of triplet excitons in the TADF material. This improves the purity of the emitted light and reduces the aging of the various film layers in the light-emitting layer, thereby increasing the lifetime of the organic light-emitting diode.

[0123] In one example, the energy difference between the first singlet level and the first triplet level of the TADF material is no greater than 0.2 eV, so as to ensure that the TADF material can effectively utilize the excitons of the first triplet level.

[0124] In one embodiment of this disclosure, the TADF material content (the percentage of the evaporation rate component of the fluorescent dopant material in the co-evaporation rate) in the light-emitting layer is greater than 5% and less than 50%.

[0125] In one embodiment of this disclosure, the luminous efficiency of the TADF material in the light-emitting layer is less than 10% of the total luminous efficiency of the organic light-emitting diode; the energy of the TADF material is mainly transferred to the fluorescent dopant material to ensure the luminescence of the fluorescent dopant material.

[0126] In one embodiment of this disclosure, in the light-emitting layer, the first triplet energy level of the fluorescent dopant is lower than the first triplet energy level of the TADF material, and the first singlet energy level of the fluorescent dopant is lower than the first singlet energy level of the TADF material, so as to ensure that excitons in the TADF material can be transferred to the fluorescent dopant material and avoid exciton backflow.

[0127] In one embodiment of this disclosure, the HOMO (highest occupied molecular orbital) energy level of the host material is greater than -6.55 eV and less than -5.75 eV; the LUMO energy level of the host material is greater than -3.2 eV and less than -2.4 eV.

[0128] In one embodiment of this disclosure, the absolute value of the energy level difference between the HOMO energy level of the hole blocking layer material and the HOMO energy level of the host material is not less than 0.15 eV; the absolute value of the energy level difference between the first triplet energy level of the hole blocking layer material and the first triplet energy level of the host material is not greater than 0.15 eV.

[0129] In one example, the HOMO energy level of the hole-blocking layer material is lower than that of the host material.

[0130] In one example, the first triplet energy level of the hole blocking layer material is slightly lower than that of the first triplet energy level of the host material. This allows the hole blocking layer to play a certain role in exciton blocking while avoiding the first triplet energy level of the hole blocking layer material being too high, which would result in too low electron mobility, thus achieving a balance between exciton blocking and improving electron injection efficiency.

[0131] In one embodiment of this disclosure, the first triplet energy level of the hole blocking layer material is lower than the first triplet energy level of the host material, and the absolute value of the energy level difference between the first triplet energy level of the hole blocking layer material and the first triplet energy level of the host material is less than 0.1 eV.

[0132] In one embodiment of this disclosure, the electron mobility of the hole-blocking layer material is not less than 5*10. - 6 cm 2 / Vs. This ensures that the hole blocking layer has a certain electron transport capability, avoiding a situation where the electron transport capability of the hole blocking layer is too weak, resulting in low efficiency of electron injection into the light-emitting layer and electron accumulation in the electron transport layer, thereby ensuring the luminous efficiency and lifespan of the organic light-emitting diode.

[0133] In one embodiment of this disclosure, the absolute value of the energy level difference between the LUMO (Least Unoccupied Orbit) level of the hole blocking layer material and the LUMO level of the host material is less than 0.4 eV. This ensures that the hole blocking layer can normally inject electrons into the light-emitting layer, avoiding a large difference between the LUMO level of the hole blocking layer material and the LUMO level of the host material. For example, it avoids the LUMO level of the hole blocking layer material being too deep, which would result in low efficiency of electron injection from the hole blocking layer into the light-emitting layer and an increase in driving voltage.

[0134] In one embodiment of this disclosure, the thickness of the hole-blocking layer is no greater than 10 nm, and particularly no greater than 5 nm. Optionally, the thickness of the hole-blocking layer is between 2 and 10 nanometers, for example, between 2 and 5 nanometers. This ensures normal electron injection and improves electron transport performance.

[0135] In one embodiment of this disclosure, the absolute value of the energy level difference between the LUMO energy level of the electron transport layer material and the LUMO energy level of the hole blocking layer material is less than 0.5 eV; the first triplet energy level of the electron transport layer material is lower than the first triplet energy level of the hole blocking layer material. This allows electrons from the electron transport layer to be smoothly injected into the hole blocking layer, thereby reducing the driving voltage and improving luminous efficiency.

[0136] In one embodiment of this disclosure, the difference between the electron mobility of the electron transport layer and the electron mobility of the hole blocking layer is no more than two orders of magnitude; for example, the electron mobility of the electron transport layer is no more than 100 times that of the hole blocking layer. More specifically, the electron mobility of the electron transport layer and the electron mobility of the hole blocking layer are within the same order of magnitude; for example, the electron mobility of the electron transport layer is no more than 10 times that of the hole blocking layer. This allows electrons from the electron transport layer to be smoothly injected into the hole blocking layer, avoiding electron accumulation due to a large difference in electron mobility between the electron transport layer and the hole blocking layer, thereby preventing efficiency degradation and material aging caused by electron accumulation.

[0137] In one embodiment of this disclosure, see Figure 1 The electron transport layer includes a first electron transport layer ETL1 and a second electron transport layer ETL2 stacked together. The first electron transport layer ETL1 is located on the side of the hole blocking layer away from the second electron transport layer ETL2. The LUMO energy levels of the hole blocking layer, the second electron transport layer ETL2, and the ETL1 decrease sequentially. This can further reduce the driving voltage and improve the luminous efficiency.

[0138] In one embodiment of this disclosure, the electron transport layer includes a first electron transport layer ETL1 and a second electron transport layer ETL2 stacked together. The first electron transport layer ETL1 is located on the side of the hole blocking layer away from the second electron transport layer ETL2. The first triplet energy levels of the hole blocking layer, the second electron transport layer ETL2, and the ETL1 decrease sequentially. In some cases, this can cause the electron mobility of the hole blocking layer, the second electron transport layer ETL2, and the ETL1 to increase sequentially, thereby further reducing the driving voltage and improving the luminous efficiency.

[0139] In one embodiment of this disclosure, the thickness of the light-emitting layer is between 10 and 30 nm.

[0140] In one embodiment of this disclosure, the thickness of the electron transport layer is between 20 and 70 nm.

[0141] In one embodiment of this disclosure, see Figure 1 Organic light-emitting diodes also include a hole transport layer (HTL), which is located between the anode and the light-emitting layer and is used to transport holes. The material of the HTL can have a high hole mobility.

[0142] In one example, the HOMO energy level of the hole transport layer material is between -5.2 eV and -5.6 eV.

[0143] In one example, the hole transport layer can be made of materials with high hole mobility, such as triarylamines or carbazoles.

[0144] In one example, the thickness of the hole transport layer can be between 100 nm and 140 nm.

[0145] In one embodiment of this disclosure, see Figure 1 The organic light-emitting diode may also include a hole injection layer (HIL) located between the hole transport layer and the anode. The hole injection layer is used to reduce the hole injection barrier and improve the efficiency of the anode injecting holes into the hole transport layer.

[0146] In one example, the material of the hole injection layer can be selected from materials such as HATCN and CuPc.

[0147] In another example, the material of the hole injection layer can be selected from the hole transport layer material doped with P-type, such as NPB:F4TCNQ, TAPC:MnO3, etc.; furthermore, the content of the dopant is 0.5% to 10%.

[0148] In one example, the thickness of the hole injection layer is 5–20 nm.

[0149] In one embodiment of this disclosure, see Figure 1 Organic light-emitting diodes may also include an electron blocking layer (EBL), which is used to inject holes into the light-emitting layer and block electrons and excitons in the light-emitting layer from diffusing to the hole transport layer.

[0150] In one example, the thickness of the electron blocking layer is 1–10 nm.

[0151] In one embodiment of this disclosure, see Figure 1 The EIL organic light-emitting diode may also include an electron injection layer, which is used to improve the efficiency of the cathode injecting electrons into the electron transport layer.

[0152] In one example, the thickness of the electron-injected layer can be between 0.5 and 2 nm.

[0153] In one embodiment of this disclosure, the anode may be made of a material with a high work function.

[0154] In one example, the organic light-emitting diode (OLED) has a bottom-emission structure, meaning that light emitted from the light-emitting layer passes through the anode. The anode can be a transparent metal oxide, such as ITO (indium tin oxide) or IZO (indium zinc oxide). Furthermore, the thickness of the anode is between 80 and 200 nm.

[0155] In another example, the organic light-emitting diode (OLED) is a top-emitting structure, meaning the light emitted from the light-emitting layer exits through the cathode. In this case, the anode can be a composite structure of a reflective layer and a transparent metal oxide layer; wherein the reflective layer is located on the side of the transparent metal oxide layer away from the light-emitting layer. Exemplarily, the anode can be a composite structure of Ag (as a reflective layer) / ITO or Ag (as a reflective layer) / IZO. Further, the thickness of the emitting layer is 80 nm to 100 nm; the thickness of the transparent metal oxide layer is 5 nm to 10 nm; and the average reflectivity of the anode in the visible light region is 85% to 95%.

[0156] In one embodiment of this disclosure, the material or thickness of the cathode can be determined as needed.

[0157] When an organic light-emitting diode (OLED) has a top-emitting structure, the light emitted from the light-emitting layer needs to exit through the cathode. In this case, the cathode can be a transparent metal electrode. In one example, the cathode can be a 10-20 nm layer of magnesium, silver, or aluminum, or a magnesium-silver alloy layer. In the magnesium-silver alloy layer, the ratio of magnesium to silver is between 3:7 and 1:9. In one example, the cathode has a transmittance of 50%-60% at 530 nm.

[0158] When the organic light-emitting diode (OLED) has a bottom-emission structure, the cathode can employ a relatively thick metal layer to ensure good reflectivity. For example, the cathode may include a silver or aluminum layer exceeding 80 nm in thickness.

[0159] This disclosure also provides a display panel having a plurality of organic light-emitting diodes as described in the above-described organic light-emitting diode embodiments.

[0160] In one embodiment of this disclosure, see Figure 2 and Figure 3 The display panel includes a substrate BP, a driving circuit layer F100, a pixel layer F200, and an encapsulation layer TFE stacked sequentially. The pixel layer F200 contains organic light-emitting diodes (OLEDs) serving as sub-pixels. Figure 2 The first organic light-emitting diode (OLED1), the second organic light-emitting diode (OLED2), and the third organic light-emitting diode (OLED3) are arranged in the driving circuit layer; the pixel driving circuit (PDC) for driving the organic light-emitting diodes is provided in the driving circuit layer.

[0161] In one embodiment of this disclosure, see Figures 2-4The pixel layer is equipped with various organic light-emitting diodes (OLEDs) of different colors (e.g., OLED1, OLED2, and OLED3), and the light-emitting layers of the different colored OLEDs are different. For example, the light-emitting layer of OLED1 is the first light-emitting layer EML1, the light-emitting layer of OLED2 is the second light-emitting layer, and the light-emitting layer of OLED3 is the third light-emitting layer EML3.

[0162] In one example, the hole blocking layer and electron transport layer of each organic light-emitting diode are identical, so as to reduce the cost of the display panel by preparing these layers through an open mask.

[0163] In one example, the electron injection layer, hole injection layer, and hole transport layer of each organic light-emitting diode are identical, so as to reduce the cost of the display panel by fabricating these layers through an open mask.

[0164] Optionally, the electron blocking layers of organic light-emitting diodes (OLEDs) of different colors can be the same or different. As an example, the electron blocking layers of OLEDs of different colors can be matched with the light-emitting layers of the OLEDs to achieve a more targeted and better electron blocking effect. For example, the electron blocking layer of the first OLED1 is a first electron blocking layer EBL1, the electron blocking layer of the second OLED2 is a second electron blocking layer, and the electron blocking layer of the third OLED3 is a third electron blocking layer EBL3.

[0165] In one embodiment of this disclosure, the main materials in the light-emitting layers of organic light-emitting diodes of different colors may be the same or different.

[0166] In one embodiment of this disclosure, the TADF material in the light-emitting layer of organic light-emitting diodes of different colors may be the same or different.

[0167] In one embodiment of this disclosure, the fluorescent doping materials in the light-emitting layers of organic light-emitting diodes of different colors may be different.

[0168] In one embodiment of this disclosure, each organic light-emitting diode on the display panel is an organic light-emitting diode as described in the above-described organic light-emitting diode embodiments.

[0169] In another embodiment of this disclosure, only a portion of the organic light-emitting diodes on the display panel are organic light-emitting diodes as described in the above-described organic light-emitting diode embodiments. For example, only the red light organic light-emitting diodes are organic light-emitting diodes as described in the above-described organic light-emitting diode embodiments.

[0170] The present disclosure presents the structures and test results of several organic light-emitting diodes (OLEDs). These OLEDs include experimental devices (experimental devices 1-5) fabricated using the OLED design scheme of the present disclosure, and control devices (control devices 1-4) fabricated not according to the OLED design scheme of the present disclosure. The thickness of each film layer in the experimental and control devices is the same; except for the light-emitting layer, hole-blocking layer, and electron transport layer, the materials of each film layer are also the same. In this case, the performance differences between the devices arise from the differences in material matching between the light-emitting layer, hole-blocking layer, and electron transport layer.

[0171] In this experiment, compounds RA-1 and RA-2 were introduced as the host materials in the emitting layer of the control device; compounds RH-1 and RH-2 were introduced as the hole blocking layer materials in the control device. In this experiment, the TADF material was compound B1, and the fluorescent doping material was compound C1.

[0172] In the electron transport layer, compound E2 is doped to improve electron mobility.

[0173]

[0174] The stacked structure of experimental device 1 is as follows:

[0175] ITO / HIL / HTL / EBL / EML(A-2:B1:C1) / HBL(H-15) / ETL(H-27:E2) / EIL / Al

[0176] The stacked structure of experimental device 2 is as follows:

[0177] ITO / HIL / HTL / EBL / EML(A-6:B1:C1) / HBL(H-15) / ETL(H-27:E2) / EIL / Al

[0178] The stacked structure of test device 3 is as follows:

[0179] ITO / HIL / HTL / EBL / EML(A-11:B1:C1) / HBL(H-15) / ETL(H-27:E2) / EIL / Al

[0180] The stacked structure of test device 4 is as follows:

[0181] ITO / HIL / HTL / EBL / EML(A-2:B1:C1) / HBL(H-15) / ETL(H-9:E2) / EIL / Al

[0182] The stacked structure of test device 5 is as follows:

[0183] ITO / HIL / HTL / EBL / EML(A-2:B1:C1) / HBL(H-15) / ETL(H-5) / ETL(H-27:E2) / EIL / Al

[0184] The stacked structure of reference device 1 is as follows:

[0185] ITO / HIL / HTL / EBL / EML(RA-1:B1:C1) / HBL(RH-1) / ETL(RH-2:E2) / EIL / Al

[0186] The stacked structure of the reference device 2 is as follows:

[0187] ITO / HIL / HTL / EBL / EML(RA-2:B1:C1) / HBL(RH-1) / ETL(RH-2:E2) / EIL / Al

[0188] The stacked structure of the reference device 3 is as follows:

[0189] ITO / HIL / HTL / EBL / EML(RA-1:B1:C1) / HBL(RH-2) / ETL(RH-2:E2) / EIL / Al

[0190] The stacked structure of the reference device 4 is as follows:

[0191] ITO / HIL / HTL / EBL / EML(RA-1:B1:C1) / HBL(H-15) / ETL(H-27:E2) / EIL / Al

[0192] The device in the above example is a bottom-emitting device. The hole injection layer (HIL) has a thickness of 10 nm, the hole transport layer (HTL) has a thickness of 100 nm, the electron blocking layer (EBL) has a thickness of 5 nm, the light-emitting layer (EML) has a thickness of 25 nm, the hole blocking layer (HBL) has a thickness of 5 nm, the electron transport layer (ETL) has a thickness of 35 nm, the electron injection layer (EIL) has a thickness of 1 nm, and the cathode (Al) has a thickness of 120 nm.

[0193] The physical properties of the various compounds involved are as follows:

[0194] Table 1: Physical property data of the main material

[0195]

[0196] "-" indicates that the electron mobility was too low to be measured.

[0197] Table 2: Physical property data of materials for hole blocking layer and electron transport layer

[0198] H-5 -6.57 -3.0 2.65 <![CDATA[1.5*10 -4 ]]> H-9 -6.30 -3.0 2.6 <![CDATA[1.2*10 -5 ]]> H-15 -6.28 -2.8 2.8 <![CDATA[6.6*10 -5 ]]> H-27 -6.65 -3.2 2.55 <![CDATA[3.7*10 -5 ]]> RH-1 -6.50 -3.0 2.8 <![CDATA[1.2*10 -4 ]]> RH-2 -6.20 -2.7 2.55 <![CDATA[0.8*10 -5 ]]>

[0199] Table 3: Test data for each device (normalized data)

[0200]

[0201] Table 3 shows that the lifetimes of control devices 1-3 are significantly shorter than those of experimental devices 1-5. This indicates that, using the same structure but different materials, the organic light-emitting diode of this disclosure can significantly reduce material aging and improve device lifetime. The main reason for this is that this disclosure uses specific host materials, hole-blocking layer materials, and electron transport layer materials to match the energy levels and carrier migration rates of each material, thereby reducing the aging rate of the materials.

[0202] In the aforementioned control devices, the host material RA-1 has a symmetrical structure and two carbazole groups, which makes RA-1 have poor electron tolerance and prone to aging, leading to a decrease in device lifespan. Therefore, in control devices 1 and 3, if the design concept of the electron blocking layer and electron transport layer in this disclosure is not improved, the material disadvantages of RA-1 will be obviously manifested, resulting in poor device lifespan for control devices 1 and 3. In control device 4, the design concept of the electron blocking layer and electron transport layer in this disclosure is adopted to improve the device, resulting in a significant increase in the device lifespan of control device 4. In other words, although RA-1 itself is prone to aging, leading to a decrease in device lifespan, the design concept of the electron blocking layer and electron transport layer in this disclosure can compensate for the defects of RA-1. This further demonstrates that the matching selection between the host material of the light-emitting layer, the electron blocking layer, and the electron transport layer of the organic light-emitting diode in this disclosure has achieved unexpected results, significantly improving the device lifespan. Of course, the inventors discovered that RA-1 has other drawbacks when applied to the light-emitting layer, such as poor film formation and low glass transition temperature due to its good molecular symmetry and small molecular weight, which reduces the fabrication feasibility of organic light-emitting diode devices.

[0203] In the aforementioned device, compound RA-2 is a bipolar material, which causes electrons and holes to recombine on RA-2, making it prone to aging.

[0204] In the aforementioned devices, the mobility mismatch between the hole-blocking material RH-1 and the electron transport material RH-2 causes electrons to accumulate at the interface between the light-emitting layer and the hole-blocking layer, accelerating the aging of the interface material and reducing the device lifetime. If RH-2 is used as the material for the hole-blocking layer, its first triplet energy level is relatively low, which can easily lead to exciton leakage, resulting in reduced exciton utilization and a significant decrease in the efficiency of the light-emitting device.

[0205] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. An organic light-emitting diode, comprising an anode, a light-emitting layer, a hole-blocking layer, an electron transport layer, and a cathode, sequentially stacked; wherein, The light-emitting layer comprises a host material, a TADF material, and a fluorescent doping material; The main material is selected from the compound shown in Chemical Formula 1, and the materials of the hole blocking layer and the electron transport layer are selected from the compound shown in Chemical Formula 2. Where m and n are both 1; k is 1 or 2; L 1 Selected from unsubstituted aryl groups with 6 to 12 cyclic carbon atoms; Ar 1 Selected from the groups shown in chemical formula 1-A and chemical formula 1-B: Chemical formula 1-A Chemical formula 1-B Ring A and ring C are each an unsubstituted benzene ring; Ring B is Z 1 Selected from O and S; Ar 2 Selected from the groups shown in chemical formulas 1-D and 1-F: Chemical formula 1-D Chemical formula 1-F Each R 4 Each is independently selected from hydrogen; X is selected from O; Y is selected from a single bond; And Ar 1 and Ar 2 Not at the same time N -Carbazole group; L 2 Selected from aryl groups with 6 to 12 single-bonded, unsubstituted cyclic carbon atoms; P 1 P 2 and P 3 Selected from N; Ar 3 Selected from the following groups: ； Q 1 Q 2 They may be the same or different, and each is independently selected as an aryl group with 6 to 12 carbon atoms in the ring.

2. The organic light-emitting diode according to claim 1, wherein, The group represented by chemical formula 1-B is selected from the following groups: 。 3. The organic light-emitting diode according to claim 1, wherein, Ar 1 Selected from the following groups: 。 4. The organic light-emitting diode according to claim 1, wherein, Ar 2 Selected from the following groups: 。 5. The organic light-emitting diode according to claim 1, wherein, The compound represented by chemical formula 1 is selected from the following compounds: 。 6. The organic light-emitting diode according to claim 1, wherein, The compound represented by chemical formula 2 is selected from the following compounds: 。 7. The organic light-emitting diode according to any one of claims 1 to 6, wherein, The HOMO energy level of the host material is greater than -6.55 eV and less than -5.75 eV; the LUMO energy level of the host material is greater than -3.2 eV and less than -2.4 eV.

8. The organic light-emitting diode according to any one of claims 1 to 6, wherein, The absolute value of the energy level difference between the HOMO energy level of the hole blocking layer material and the HOMO energy level of the host material is not less than 0.15 eV; the absolute value of the energy level difference between the first triplet energy level of the hole blocking layer material and the first triplet energy level of the host material is not greater than 0.15 eV.

9. The organic light-emitting diode according to claim 8, wherein, The first triplet energy level of the hole blocking layer material is lower than the first triplet energy level of the host material, and the absolute value of the energy level difference between the first triplet energy level of the hole blocking layer material and the first triplet energy level of the host material is less than 0.1 eV.

10. The organic light-emitting diode according to any one of claims 1 to 6, wherein, The electron mobility of the hole-blocking layer material is not less than 5*10. -6 cm 2 / Vs.

11. The organic light-emitting diode according to any one of claims 1 to 6, wherein, The absolute value of the energy level difference between the LUMO energy level of the hole blocking layer material and the LUMO energy level of the host material is less than 0.4 eV.

12. The organic light-emitting diode according to any one of claims 1 to 6, wherein, The thickness of the hole blocking layer is no greater than 10 nm; the thickness of the light-emitting layer is between 10 and 30 nm.

13. The organic light-emitting diode according to any one of claims 1 to 6, wherein, The absolute value of the energy level difference between the LUMO energy level of the electron transport layer material and the LUMO energy level of the hole blocking layer material is less than 0.5 eV; the first triplet energy level of the electron transport layer material is less than the first triplet energy level of the hole blocking layer material.

14. The organic light-emitting diode according to any one of claims 1 to 6, wherein, The electron mobility of the electron transport layer does not exceed 100 times the electron mobility of the hole blocking layer.

15. The organic light-emitting diode according to any one of claims 1 to 6, wherein, The electron transport layer includes a first electron transport layer and a second electron transport layer stacked together, with the first electron transport layer located on the side of the hole blocking layer away from the second electron transport layer; the first triplet energy levels of the hole blocking layer, the second electron transport layer and the first electron transport layer decrease sequentially.

16. A display panel comprising an organic light-emitting diode as described in any one of claims 1 to 15.

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