Light-emitting device, display panel, and display apparatus

Abstract

A light-emitting device, a display panel, and a display apparatus, which relate to the technical field of display, and are used for improving the light emission efficiency of the light-emitting device and the service life of the device. The light-emitting device (100) comprises a first electrode (11) and a second electrode (12) that are arranged in a stacked manner, and at least one light-emitting unit (13) that is arranged between the first electrode (11) and the second electrode (12), wherein the light-emitting unit (13) comprises a light-emitting layer (131), which is made of a first host material, a second host material, and a guest material. The difference between the triplet-state energy level of the first host material and the triplet-state energy level of the guest material is greater than or equal to 0 and is less than or equal to 0.4eV; and the difference between the triplet-state energy level of the second host material and the triplet-state energy level of the guest material is greater than or equal to 0 and is less than or equal to 0.4eV.

Description

Light-emitting device, display panel, and display apparatus

[0001] This application claims priority to Chinese patent application No. 202311041807.5 filed on August 17, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present disclosure relates to the field of display technology, and in particular to a light-emitting device, a display panel, and a display apparatus. Background Art

[0003] Organic Light Emitting Diode (OLED) display panels have the advantages of self-luminescence, high color gamut, high saturation, and high response speed. They are widely used in display screens such as mobile phones, tablets, and car displays.

[0004] Summary of the Invention

[0005] In one aspect, a light-emitting device is provided, comprising a first electrode and a second electrode stacked together, and at least one light-emitting unit disposed between the first electrode and the second electrode. The light-emitting unit includes a light-emitting layer, and the materials of the light-emitting layer include: a first host material, a second host material, and a guest material. The difference between the triplet energy level of the first host material and the triplet energy level of the guest material is greater than or equal to 0 and less than or equal to 0.4 eV. The difference between the triplet energy level of the second host material and the triplet energy level of the guest material is greater than or equal to 0 and less than or equal to 0.4 eV.

[0006] In some embodiments, the light-emitting unit further includes a hole transport layer located on a side of the light-emitting layer adjacent to the first electrode and in contact with the light-emitting layer. The hole transport layer comprises a hole transport material. The exciplex of the light-emitting unit includes a first exciplex and a second exciplex; the first exciplex is an exciplex formed by the first host material and the second host material; the second exciplex is an exciplex formed by the hole transport material and the second host material.

[0007] In some embodiments, the interface between the hole transport layer and the light-emitting layer contains a first exciplex and a second exciplex.

[0008] In some embodiments, an absolute value of a difference between a peak wavelength of an emission spectrum of the first exciplex and a peak wavelength of an emission spectrum of the second exciplex is less than or equal to 10 nm.

[0009] In some embodiments, the first host material is selected from any one of the structures represented by formula (I).

[0010] R1 and R2 are the same or different and are independently selected from any one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted dimethylfluorenyl group, a substituted or unsubstituted diphenylfluorenyl group, and a substituted or unsubstituted spirofluorenyl group. L1 and L2 are the same or different and are independently selected from any one of a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, and a substituted or unsubstituted naphthylene group. n1 and n2 are the same or different and are independently selected from any one of 0 and 1. n3 and n6 are the same or different and are independently selected from any one of 0, 1, 2, 3, and 4. n4 and n5 are the same or different and are independently selected from any one of 0, 1, and 2.

[0011] In some embodiments, the second host material is selected from any one of the structures represented by formula (II).

[0012] Wherein, L3, L4 and L5 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene, substituted or unsubstituted benzodibenzofuranylene, substituted or unsubstituted dibenzothiophenylene, substituted or unsubstituted benzodibenzothiophenylene, substituted or unsubstituted carbazolylene, substituted or unsubstituted benzocarbazolylene and substituted or unsubstituted phenanthroxazolyl. R3, R4, and R5 are the same or different and are independently selected from any one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted benzodibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted benzodibenzothiophenyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted benzocarbazolyl group, and a substituted or unsubstituted phenanthroxazolyl group. n7, n8, and n9 are the same or different and are independently selected from any one of 0 and 1.

[0013] In some embodiments, the hole transport functional material is selected from any one of the structures represented by formula (III).

[0014] Wherein, L6, L7, and L8 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene, and substituted or unsubstituted dibenzothiophenylene. R6, R7, and R8 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene, substituted or unsubstituted dibenzothiophenylene, substituted or unsubstituted dimethylfluorenylene, substituted or unsubstituted diphenylfluorenylene, substituted or unsubstituted spirofluorenylene, and substituted or unsubstituted adamantylene. 10 、n 11 and n 12 are the same or different, and are independently selected from any one of 0 and 1.

[0015] In some embodiments, at least one of the first host material, the second host material, and the hole transport functional material is a deuterated material.

[0016] In some embodiments, a weight ratio of the first host material to the second host material is greater than or equal to 3:7 and less than or equal to 1:1.

[0017] In some embodiments, the first host material is selected from any one of the structures represented by formula (IV);

[0018] Wherein, L9 is selected from any one of a single bond, a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group. Ar1 and Ar2 are fused; Ar1 ​​and Ar2 share two carbon atoms, which are X a and X b , and, X a and X b Any two adjacent numbers among X1, X2, X3, X4 and X5. a and X b The remaining three are independently selected from N and C (R a ) in any one of R a Ar1 is selected from any one of Ar1-a to Ar1-i.

[0019] Y is selected from O, S, Se, C=O, S(=O)2, C(R b R c )、Si(R d R e )、N(R f )、P(Rg )、P(=O)(R h ) and B(R i ) in any one of R9, R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 、R 29 、R b 、R c 、R d 、R e 、R f 、R g 、R h and R i The same or different substituents are independently selected from any one of hydrogen, tritium, halogen, nitrile, nitro, hydroxyl, carbonyl, ester, imide, amide, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted alkylthio, substituted or unsubstituted arylthio, substituted or unsubstituted alkylsulfonyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted alkenyl, substituted or unsubstituted silyl, substituted or unsubstituted boron, substituted or unsubstituted amine, substituted or unsubstituted arylphosphino, substituted or unsubstituted phosphinyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and substituted or unsubstituted heterocyclic groups, or may be linked to adjacent substituents to form a substituted or unsubstituted ring. 13 、n 16 、n 18 、n 20 and n 22 The same or different, each independently selected from any one of 0, 1 and 2. 14 、n 15 、n 17 、n 19 、n 21 and n 23 The same or different, each independently selected from any one of 0, 1, 2, 3 and 4.

[0020] In some embodiments, the general formula (IV) satisfies at least one of the following conditions (a) to (m): (a) R9, R 10 、R 11 、R 12 and R 13 In the example, every two adjacent pairs form a group, and at least one group forms a ring. (b) R 14 、R 15 、R 16 、R 17 and R 18 In the example, every two adjacent pairs form a group, and at least one group forms a ring. (c) In n 13 When the value is 2, the two R 19 Bonding to form a ring. (d) in n 14 When it is greater than or equal to 2, every two adjacent R 20 As a group, at least one group is bonded to form a ring. (e) In n 15 When it is greater than or equal to 2, every two adjacent R 21 As a group, at least one group is bonded into a ring. (f) In n 16 When the value is 2, the two R 22 Bonding to form a ring. (g) in n 17 When it is greater than or equal to 2, every two adjacent R 23 As a group, at least one group is bonded to form a ring. (h) in n 18 When the value is 2, the two R 24 Bond to form a ring. (i) In n 19 When it is greater than or equal to 2, every two adjacent R 25 As a group, at least one group is bonded to form a ring. (j) In n 20 When the value is 2, the two R 26 Bonding into a ring. (k) in n 21 When it is greater than or equal to 2, every two adjacent R 27 As a group, at least one group is bonded to form a ring. (l) In n 22 When the value is 2, the two R 28 Bonding into a ring. (m) in n 23 When it is greater than or equal to 2, every two adjacent R 29 As a group, at least one group is bonded to form a ring.

[0021] In some embodiments, R9, R 10 、R 11 、R 12 and R 13 At least one of them is deuterium. 14 、R 15 、R 16 、R 17 and R 18In the case where L9 is a single bond, at least one of X1, X2, X3, X4, and X5 is a deuterated carbon. When L9 is selected from any one of a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group, L9 is a deuterated group.

[0022] In some embodiments, when L9 is a single bond, the ratio of the number of deuterium atoms and the number of hydrogen atoms to the total number of deuterium atoms in Ar3, Ar4, and Ar2 is greater than or equal to 50%. When L9 is selected from any one of a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group, the ratio of the number of deuterium atoms and the number of hydrogen atoms to the total number of deuterium atoms in Ar3, Ar4, and L9 is greater than or equal to 50%.

[0023] In some embodiments, the second host material is selected from any one of the structures represented by formula (V).

[0024] Among them, L 10 Any one selected from a single bond, a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group. 10 the same or different, independently selected from N and C(R j ) in any one of R j Any one selected from hydrogen, deuterium, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl, or may be linked with adjacent substituents to form a substituted or unsubstituted ring. 30 and R 31 The same or different groups are independently selected from any one of hydrogen, tritium, halogen, nitrile, nitro, hydroxyl, carbonyl, ester, imide, amide, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted alkylthio, substituted or unsubstituted arylthio, substituted or unsubstituted alkylsulfonyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted alkenyl, substituted or unsubstituted silyl, substituted or unsubstituted boron, substituted or unsubstituted amine, substituted or unsubstituted arylphosphino, substituted or unsubstituted phosphinyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and substituted or unsubstituted heterocyclic groups. 24 and n 25The same or different substituents are independently selected from any one of 0, 1, 2, 3, 4 and 5, or may be linked with adjacent substituents to form a substituted or unsubstituted ring.

[0025] In some embodiments, the general formula (V) satisfies at least one of the following conditions (n) to (p): (n) when X6, X7, X8, X9 and X 10 In the example, every two adjacent pairs form a group, and at least two pairs in a group are C(R j ), two R j Bonding to form a ring. (o) in n 24 When it is greater than or equal to 2, every two adjacent R 30 As a group, at least one group is bonded into a ring. (p) in n 25 When it is greater than or equal to 2, every two adjacent R 31 As a group, at least one group is bonded to form a ring.

[0026] In some embodiments, in L 10 When L is a single bond, at least one of Ar5, Ar6 and Ar7 is a deuterated group. 10 In the case of any one selected from substituted or unsubstituted C1-C30 alkylene, substituted or unsubstituted C6-C30 arylene and substituted or unsubstituted C6-C30 heteroarylene, Ar5, Ar6 and L 10 wherein at least one is a deuterated group.

[0027] In some embodiments, the ratio of the number of hydrogen atoms and the sum of the number of hydrogen atoms and the number of deuterium atoms in the deuterated group is greater than or equal to 20%.

[0028] In some embodiments, a weight ratio of the first host material to the second host material is greater than or equal to 2:8 and less than or equal to 8:2.

[0029] In some embodiments, the light emitting device is configured to emit light of a first wavelength, the light of the first wavelength is red light; the chromaticity coordinate CIEx of the red light ranges from 0.678 to 0.684; the chromaticity coordinate CIEy of the red light ranges from 0.316 to 0.323.

[0030] In another aspect, a light-emitting device is provided, comprising: a first electrode and a second electrode stacked together, and at least one light-emitting unit disposed between the first electrode and the second electrode. The light-emitting unit comprises a light-emitting layer and a hole transport layer, wherein the hole transport layer is located on a side of the light-emitting layer adjacent to the first electrode and in contact with the light-emitting layer. The material of the light-emitting layer comprises: a first host material, a second host material, and a guest material. The material of the hole transport layer comprises a hole transport material. The exciplex of the light-emitting unit comprises a first exciplex and a second exciplex; the first exciplex is an exciplex formed by the first host material and the second host material; and the second exciplex is an exciplex formed by the hole transport material and the second host material.

[0031] In some embodiments, the interface between the hole transport layer and the light-emitting layer contains a first exciplex and a second exciplex.

[0032] In some embodiments, the absolute value of the difference between the wavelength corresponding to the peak of the emission spectrum of the first exciplex and the wavelength corresponding to the peak of the emission spectrum of the second exciplex is less than or equal to 10 nm.

[0033] In some embodiments, under a predetermined electric field strength, a ratio of the electron mobility of the second host material to the hole mobility of the first host material is greater than or equal to 10 and less than or equal to 1000.

[0034] In some embodiments, the difference between the triplet energy level of the first host material and the triplet energy level of the guest material is greater than or equal to 0 and less than or equal to 0.4 eV; the difference between the triplet energy level of the second host material and the triplet energy level of the guest material is greater than or equal to 0 and less than or equal to 0.4 eV.

[0035] In some embodiments, the absolute value of the difference between the highest occupied molecular orbital energy level of the first host material and the highest occupied molecular orbital energy level of the guest material is less than or equal to 0.4 eV; the absolute value of the difference between the lowest unoccupied molecular orbital energy level of the second host material and the lowest unoccupied molecular orbital energy level of the guest material is less than or equal to 0.4 eV.

[0036] In some embodiments, the first host material is selected from any one of the structures represented by formula (I).

[0037] R1 and R2 are the same or different and are independently selected from any one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted dimethylfluorenyl group, a substituted or unsubstituted diphenylfluorenyl group, and a substituted or unsubstituted spirofluorenyl group. L1 and L2 are the same or different and are independently selected from any one of a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, and a substituted or unsubstituted naphthylene group. n1 and n2 are the same or different and are independently selected from any one of 0 and 1. n3 and n6 are the same or different and are independently selected from any one of 0, 1, 2, 3, and 4. n4 and n5 are the same or different and are independently selected from any one of 0, 1, and 2.

[0038] In some embodiments, the second host material is selected from any one of the structures represented by formula (II).

[0039] Wherein, L3, L4 and L5 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene, substituted or unsubstituted benzodibenzofuranylene, substituted or unsubstituted dibenzothiophenylene, substituted or unsubstituted benzodibenzothiophenylene, substituted or unsubstituted carbazolylene, substituted or unsubstituted benzocarbazolylene and substituted or unsubstituted phenanthroxazolyl. R3, R4, and R5 are the same or different and are independently selected from any one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted benzodibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted benzodibenzothiophenyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted benzocarbazolyl group, and a substituted or unsubstituted phenanthroxazolyl group. n7, n8, and n9 are the same or different and are independently selected from any one of 0 and 1.

[0040] In some embodiments, the hole transport functional material is selected from any one of the structures represented by formula (III).

[0041] Wherein, L6, L7, and L8 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene, and substituted or unsubstituted dibenzothiophenylene. R6, R7, and R8 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene, substituted or unsubstituted dibenzothiophenylene, substituted or unsubstituted dimethylfluorenylene, substituted or unsubstituted diphenylfluorenylene, substituted or unsubstituted spirofluorenylene, and substituted or unsubstituted adamantylene. 10 、n 11 and n 12 are the same or different, and are independently selected from any one of 0 and 1.

[0042] In some embodiments, at least one of the first host material, the second host material, and the hole transport functional material is a deuterated material.

[0043] In some embodiments, a weight ratio of the first host material to the second host material is greater than or equal to 3:7 and less than or equal to 1:1.

[0044] In some embodiments, the light emitting device is configured to emit light of a first wavelength, which is red light; the chromaticity coordinate CIEx of the red light ranges from 0.678 to 0.684; the chromaticity coordinate CIEy of the red light ranges from 0.316 to 0.323.

[0045] In another aspect, a display panel is provided. The display panel includes a plurality of light-emitting devices according to any of the above embodiments and a plurality of pixel driving circuits. Each of the plurality of pixel driving circuits is electrically connected to a light-emitting device and is configured to drive the light-emitting device to emit light.

[0046] In another aspect, a display device is provided. The display device includes a display panel as described in any of the above embodiments and a driver chip. The driver chip is used to drive the display panel to display. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] To more clearly illustrate the technical solutions of the present disclosure, the following briefly introduces the drawings required for use in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure, and those skilled in the art can also derive other drawings based on these drawings. Furthermore, the drawings described below are schematic diagrams and are not intended to limit the actual dimensions of the products, actual processes of the methods, actual timing of signals, and the like involved in the embodiments of the present disclosure.

[0048] FIG1 is a structural diagram of a display device according to some embodiments;

[0049] FIG2 is a structural diagram of a display panel according to some embodiments;

[0050] FIG3 is a structural diagram of a light-emitting substrate according to some embodiments;

[0051] FIG4 is a structural diagram of a light-emitting substrate according to some further embodiments;

[0052] FIG5 is a structural diagram of a light emitting device according to some embodiments;

[0053] FIG6 is a structural diagram of a light emitting device according to yet other embodiments;

[0054] FIG7 is a diagram of an energy transfer process according to some embodiments;

[0055] FIG8 is a diagram of an energy transfer process according to yet other embodiments;

[0056] FIG9 is a comparison diagram of exciton recombination regions according to some embodiments;

[0057] FIG10 is a diagram illustrating material distribution at the interface between the hole transport functional layer and the light emitting layer according to some embodiments;

[0058] FIG11 is a graph showing changes in normalized exciton intensity at different locations in a light-emitting layer according to some embodiments;

[0059] FIG12 is a diagram showing HOMO electron cloud distribution of comparative materials according to some embodiments;

[0060] FIG13 is a photoluminescence spectrum diagram according to some embodiments;

[0061] FIG14 is a HOMO electron cloud distribution diagram of a first host material according to some embodiments;

[0062] FIG15 is a HOMO electron cloud distribution diagram of the first host material according to some further embodiments;

[0063] FIG16 is a HOMO electron cloud distribution diagram of the first host material according to some further embodiments;

[0064] FIG17 is a HOMO electron cloud distribution diagram of a first host material according to some other embodiments;

[0065] FIG18 is a diagram showing the LUMO electron cloud distribution of a second host material according to some embodiments;

[0066] FIG19 is a LUMO electron cloud distribution diagram of a second host material according to some further embodiments;

[0067] FIG20 is a LUMO electron cloud distribution diagram of a second host material according to some further embodiments;

[0068] FIG. 21 is a diagram showing the LUMO electron cloud distribution of the second host material according to some other embodiments. DETAILED DESCRIPTION

[0069] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the embodiments described are only some embodiments of the present disclosure, not all embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present disclosure.

[0070] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and its other forms, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open and inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" are intended to indicate that the particular features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the particular features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0071] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0072] “At least one of A, B and C” has the same meaning as “at least one of A, B or C” and both include the following combinations of A, B and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B and C.

[0073] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0074] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of deviation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0075] As used herein, "parallel", "perpendicular", and "equal" include the situations described and situations similar to the situations described, and the range of the similar situations is within an acceptable deviation range, wherein the acceptable deviation range is as determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity can also be, for example, a deviation within 5°. "Equal" includes absolute equality and approximate equality, wherein the acceptable deviation range of approximate equality can be, for example, that the difference between the two equals is less than or equal to 5% of either one.

[0076] It will be understood that when a layer or element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present therebetween.

[0077] Exemplary embodiments are described herein with reference to cross-sectional and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are contemplated. Therefore, the exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include deviations in shape due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device and are not intended to limit the scope of the exemplary embodiments.

[0078] It should be noted that, for example, 11-1 in the drawings of this disclosure indicates that component 11 belongs to component 1, and for example, 220-200 in FIG2 indicates that the light-emitting functional layer 220 belongs to the light-emitting substrate 200. Other similar reference numerals in the drawings also follow the above description. For example, 1 / 2 in the drawings of this disclosure indicates that both structure 1 and structure 2 can refer to this structure, and for example, 101 / 100 in FIG3 indicates that both the first light-emitting device 100 and the light-emitting device 101 can refer to this structure. Other similar reference numerals in the drawings also follow the above description.

[0079] As shown in FIG. 1 , some embodiments of the present disclosure provide a display device 400 , which includes a display panel 300 .

[0080] The display device 400 may be, for example, an OLED (Organic Light Emitting Diode) display device 400 .

[0081] 1 , the display device 400 further includes a driver chip 410. The driver chip 410 is used to drive the display panel 300 to perform display.

[0082] In addition, the display device 400 may also include an under-screen camera and an under-screen fingerprint recognition sensor, so that the display device 400 can realize various functions such as taking pictures, recording videos, fingerprint recognition or face recognition.

[0083] The display device 400 can be any display device that displays either motion (e.g., video) or fixed (e.g., still images) and text or images. More specifically, it is contemplated that the display device 400 of the embodiments described herein can be implemented in or associated with a variety of electronic devices, such as (but not limited to) mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, video cameras, game consoles, watches, clocks, calculators, television monitors, flat-panel displays, computer monitors, automotive displays (e.g., speedometer displays), navigation systems, cockpit controls and / or displays, camera view displays (e.g., displays for rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging, and aesthetic structures (e.g., displays for images of a piece of jewelry), and the like.

[0084] In some embodiments, as shown in FIG2 , the display panel 300 includes a light-emitting substrate 200. In some examples, the light-emitting substrate 200 includes a substrate 210 and a light-emitting functional layer 220 disposed on the substrate 210. The light-emitting functional layer 220 includes a plurality of light-emitting devices 100. The plurality of light-emitting devices 100 are arranged along a first direction X, and the first direction X is parallel to the plane of the substrate 210.

[0085] In some examples, as shown in FIG2 , the display panel 300 further includes an array layer 310 disposed between the substrate 210 and the light-emitting functional layer 220. The array layer 310 includes a plurality of pixel driving circuits 311, wherein the pixel driving circuits 311 include a plurality of transistors TFT. Each pixel driving circuit 311 is electrically connected to a light-emitting device 100 to drive the light-emitting device 100 to emit light.

[0086] For example, in the display panel 300, the pixel driving circuit 311 can generate a driving current. Each light-emitting device 100 can emit light under the driving action of the driving current generated by the corresponding pixel driving circuit 311. The light emitted by multiple light-emitting devices 100 cooperates with each other, thereby enabling the display panel 300 to achieve a display function.

[0087] In some examples, as shown in Figure 2, the display panel 300 also includes an encapsulation layer 320, and the array layer 310, the light-emitting functional layer 220 and the encapsulation layer 320 are stacked on the substrate 210, and the array layer 310, the light-emitting functional layer 220 and the encapsulation layer 320 are arranged in sequence in a direction away from the substrate 210.

[0088] Exemplarily, the display panel 300 may be an OLED display panel. In this case, the encapsulation layer 320 covers the light-emitting device 100, encapsulating the light-emitting device 100 to prevent moisture and oxygen in the external environment from entering the display panel 300 and damaging the organic material in the light-emitting device 100, thereby shortening the life of the OLED display panel 300.

[0089] In some embodiments, as shown in Figures 2 and 3, in the light-emitting substrate 200, the light-emitting functional layer 220 also includes a pixel defining layer 221 arranged on one side of the substrate 210, and the pixel defining layer 221 has multiple openings Q. Multiple light-emitting devices 100 can be arranged one-to-one corresponding to the multiple openings Q.

[0090] In some embodiments, as shown in Figures 3 and 4, the plurality of light-emitting devices 100 of the light-emitting substrate 200 include a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103. Under the action of a driving voltage, the first light-emitting device 101 is configured to emit light of a first wavelength, which is red light, the second light-emitting device 102 is configured to emit light of a second wavelength, which is green light, and the third light-emitting device 103 is configured to emit light of a third wavelength, which is blue light.

[0091] By setting up multiple light-emitting devices 100 including a first light-emitting device 101, a second light-emitting device 102 and a third light-emitting device 103, the brightness (grayscale) of the first light-emitting device 101, the second light-emitting device 102 and the third light-emitting device 103 can be adjusted respectively, and the display of multiple colors can be achieved through color combination and superposition, thereby realizing full-color display of the display panel 300.

[0092] It should be noted that Figure 4 is a simplified schematic diagram obtained after removing other film layers in the light-emitting substrate 200 except the film layers related to the light-emitting device 100. In Figure 4, the multiple light-emitting devices 100 are, for example, a first light-emitting device 101, a second light-emitting device 102 and a third light-emitting device 103.

[0093] 3 to 5 , the light emitting device 100 includes a first electrode 11 and a second electrode 12 stacked together, and at least one light emitting unit 13 disposed between the first electrode 11 and the second electrode 12. The light emitting unit 13 includes a light emitting layer 131.

[0094] Illustratively, the first electrode 11 is an anode, and the second electrode 12 is a cathode. Alternatively, the first electrode 11 is a cathode, and the second electrode 12 is an anode. During operation, a voltage is applied to the first electrode 11 and the second electrode 12, generating an electric field between them. This drives the anode holes and cathode electrons to recombine in the light-emitting layer 131, thereby emitting light.

[0095] 3 , the first electrode 11 may be located on a side of the light emitting unit 13 close to the substrate 210, and the second electrode 12 may be located on a side of the light emitting unit 13 away from the substrate 210. In other examples, the first electrode 11 may be located on a side of the light emitting unit 13 away from the substrate 210, and the second electrode 12 may be located on a side of the light emitting unit 13 close to the substrate 210.

[0096] For example, in order to ensure that the light-emitting device 100 can effectively emit light, the first electrode 11 can be made of a material with a high work function, such as a material with a work function greater than 6 eV; the second electrode 12 can be made of a material with a low work function, such as a material with a work function less than a set value, and the set value can range from 2.0 eV to 3.0 eV. In this way, the holes in the anode and the electrons in the cathode can effectively migrate to the light-emitting layer 131 of the light-emitting unit 13 under the drive of the electric field, thereby compounding and emitting light.

[0097] In some examples, the material of the first electrode 11 may be a transparent conductive metal oxide material, for example, the material of the first electrode 11 may be indium tin oxide (ITO) or indium zinc oxide (IZO).

[0098] In some examples, the material of the second electrode 12 may be a metal material, for example, the material of the second electrode 12 may be magnesium, silver, aluminum, or a magnesium-silver alloy.

[0099] In some embodiments, as shown in FIG6 , a cathode cover layer 15 is further provided between the encapsulation layer 320 and the second electrode 12 in the light-emitting substrate 200. The material forming the cathode cover layer 15 is, for example, a material with a high refractive index. By providing the cathode cover layer 15, the high refractive index of the material can be utilized to improve the light extraction efficiency of the light-emitting device 100, thereby increasing the efficiency and brightness of the light-emitting device 100 when it is turned on.

[0100] It should be noted that FIG6 is a simplified schematic diagram obtained after removing the other film layers in the display panel 300 except the film layers related to the light-emitting device 100. In FIG6 , the light-emitting device 100 is, for example, the first light-emitting device 101.

[0101] In some examples, as shown in Figures 3 and 4, the light-emitting device 100 includes a single light-emitting unit 13. In this case, the light-emitting device 100 is a single-layer light-emitting device, and the first electrode 11, the light-emitting unit 13, and the second electrode 12 are stacked along the second direction Y, which intersects the first direction X. In other examples, as shown in Figure 5, the light-emitting device 100 includes multiple (for example, two) stacked light-emitting units 13. In this case, the light-emitting device 100 is a stacked light-emitting device, and the first electrode 11, the multiple light-emitting units 13, and the second electrode 12 are stacked along the second direction Y.

[0102] Exemplarily, as shown in FIG. 3 to FIG. 5 , the second direction Y is perpendicular to the first direction X.

[0103] In some embodiments, as shown in FIG. 5 , when the light emitting device 100 includes a plurality of light emitting units 13 , the light emitting device 100 further includes a charge generation layer 14 , which is located between two adjacent light emitting units 13 in the plurality of light emitting units 13 .

[0104] Through the charge generation layer 14, multiple light-emitting units 13 can be sequentially connected in a direction perpendicular to the light-emitting surface (e.g., the second direction Y). Furthermore, the charge generation layer 14 in the stacked OLED light-emitting device 100 not only connects the light-emitting units 13 but also helps improve the efficiency of charge (holes or electrons) generation, significantly impacting the performance of the light-emitting device 100.

[0105] In some embodiments, as shown in Figures 3 to 5, to improve the luminous efficiency of the light-emitting device 100, the light-emitting unit 13 further includes a hole transport functional layer 132, which is located on the side of the light-emitting layer 131 near the first electrode 11 and contacts the light-emitting layer 131. The hole transport functional layer 132, for example, includes at least one of a stacked hole injection layer 1321 (HIL) and a hole transport layer (HTL). The hole transport layer (HTL) may include at least one of a first hole transport layer 1322 and a second hole transport layer 1323. When the hole transport functional layer 132 includes the hole injection layer 1321, the first hole transport layer 1322, and the second hole transport layer 1323, the hole injection layer 1321, the first hole transport layer 1322, and the second hole transport layer 1323 are arranged in sequence away from the first electrode 11, with the second hole transport layer 1323 contacting the light-emitting layer 131.

[0106] In some embodiments, as shown in Figures 3 to 5, to improve the luminous efficiency of the light-emitting device 100, the light-emitting unit 13 further includes an electron transport functional layer 133, which is located on the side of the light-emitting layer 131 close to the second electrode 12 and in contact with the light-emitting layer 131. The electron transport functional layer 133, for example, includes at least one of a stacked electron injection layer 1331 (Electron Inject Layer, EIL), an electron transport layer 1332 (Electron Transport Layer, ETL), and a hole blocking layer 1333 (Hole Blocking Layer, EBL). When the electron transport functional layer 133 includes the electron injection layer 1331, the electron transport layer 1332, and the hole blocking layer 1333, the electron injection layer 1331, the electron transport layer 1332, and the hole blocking layer 1333 are arranged in sequence in a direction away from the second electrode 12, and the hole blocking layer 1333 is in contact with the light-emitting layer 131.

[0107] By setting up the film layers such as the hole injection layer 1321, the first hole transport layer 1322, the second hole transport layer 1323, the electron injection layer 1331, the electron transport layer 1332, and the hole blocking layer 1333, it is equivalent to setting transition steps between the first electrode 11 and the light-emitting layer 131, and between the second electrode 12 and the light-emitting layer 131, thereby reducing the potential barrier height that needs to be overcome for carrier transition, thereby making the luminescence efficiency higher.

[0108] Exemplarily, the hole transport functional layer 132 is configured to transport holes and / or block electrons and excitons generated in the light-emitting layer 131. For example, the hole injection layer 1321 can be configured to lower the hole injection barrier and improve the hole injection efficiency. The first hole transport layer 1322 can be configured to transport holes. The second hole transport layer 1323 can be configured to transport holes and block electrons and excitons generated in the light-emitting layer 131.

[0109] Exemplarily, the electron transport functional layer 133 is configured to transport electrons and / or block holes and excitons generated in the light emitting layer 131 .

[0110] In some embodiments, as shown in FIG4 , when the plurality of light-emitting devices 100 include a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103, the second electrodes 12 of the plurality of light-emitting devices 100 are structured to be interconnected throughout the entire layer, i.e., the second electrode 12 can be a common electrode shared by the plurality of light-emitting devices 100. The hole injection layer 1321 of the plurality of light-emitting devices 100 can also be structured to be interconnected throughout the entire layer, i.e., the hole injection layer 1321 can be a common film layer shared by the plurality of light-emitting devices 100. The first hole transport layer 1322, the second hole transport layer 1323, the electron injection layer 1331, the electron transport layer 1332, and the hole blocking layer 1333 can also be common film layers shared by the plurality of light-emitting devices 100, and further description thereof will not be given here.

[0111] For example, as shown in FIG. 3 , when the second electrode 12 is a common electrode shared by a plurality of light-emitting devices 100 , the second electrode 12 is simultaneously formed on a side of the pixel defining layer 221 away from the substrate 210 .

[0112] In other embodiments, as shown in FIG4 , when the plurality of light-emitting devices 100 include a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103, the second hole transport layers 1323 of the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 are independently arranged. In this way, the material of the second hole transport layer 1323 with matching performance can be selected as needed according to the different materials of the light-emitting layer 131.

[0113] In some embodiments, the material of the light emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D.

[0114] For example, the first host material HP can be configured to transport holes and / or to form excitons with recombined electrons and holes, and transfer fluorescence resonance energy to the guest material D. In this case, the hole mobility of the first host material HP is greater than or equal to the hole mobility of the second host material HN.

[0115] Exemplarily, the second host material HN can be configured to: transport electrons, and / or recombine electrons and holes to form excitons, and transfer fluorescence resonance energy to the guest material D. In this case, the electron mobility of the second host material HN is greater than or equal to the electron mobility of the first host material HP.

[0116] For example, the guest material D may be configured to emit photons using energy obtained by fluorescence resonance energy transfer from the first host material HP and / or the second host material HN, and / or to emit photons by forming excitons from recombined electrons and holes.

[0117] In some examples, the guest material D is a fluorescent material that can emit light using singlet excitons; in other examples, the guest material D is a phosphorescent material or a delayed fluorescent material that can emit light using triplet excitons.

[0118] As mentioned in the background, OLED technology is gaining increasing attention in academia and industry within the field of organic semiconductors and has been successfully applied in commercial flat-panel displays and lighting. Different combinations of guest material D, first host material HP, and second host material HN used in the light-emitting layer 131 of an OLED light-emitting device can significantly impact the overall performance of the light-emitting device 100. With the development of OLED light-emitting devices, performance requirements for efficiency, lifespan, and other aspects of OLED light-emitting devices are becoming increasingly stringent, and existing organic materials are no longer able to meet these requirements.

[0119] Based on this, some embodiments of the present disclosure provide a light-emitting device 100. The difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D is greater than or equal to 0 and less than or equal to 0.4 eV. The difference between the triplet energy level T1(HN) of the second host material HN and the triplet energy level T1(D) of the guest material D is greater than or equal to 0 and less than or equal to 0.4 eV. That is, 0≤T1(HP)-T1(D)≤0.4 eV, and 0≤T1(HN)-T1(D)≤0.4 eV.

[0120] It can be understood that when the light-emitting device 100 emits light, the first host material HP and the second host material HN can form an excimer complex HP / HN, and the triplet energy level T1(HP / HN) of the excimer complex HP / HN is lower than the triplet energy level T1(HP) of the first host material HP, and lower than the triplet energy level T1(HN) of the second host material HN. Therefore, by setting 0≤T1(HP)-T1(D)≤0.4eV and 0≤T1(HN)-T1(D)≤0.4eV, on the one hand, the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(HN) of the second host material HN can be made higher than the triplet energy level T1(D) of the guest material D. In this way, the triplet energy level T1(HP / HN) of the exciplex HP / HN can be higher than the triplet energy level T1(D) of the guest material D, thereby realizing energy transfer from the exciplex HP / HN to the guest material D, preventing exciton quenching caused by exciton backflow during the energy transfer process, and improving the efficiency of the light-emitting device 100. On the other hand, the difference between the triplet energy level T1(HP / HN) of the excited complex HP / HN and the triplet energy level T1(D) of the guest material D can be made relatively small, thereby improving the energy transfer efficiency, enhancing the adequacy of energy transmission, and improving the efficiency of the light-emitting device 100.

[0121] For example, the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D may be 0 eV, 0.1 eV, 0.2 eV, 0.3 eV, or 0.4 eV.

[0122] For example, the difference between the triplet energy level T1(HN) of the second host material HN and the triplet energy level T1(D) of the guest material D may be 0 eV, 0.15 eV, 0.2 eV, 0.3 eV, or 0.4 eV.

[0123] In the related art, the material of the hole transport functional layer 132 of some light-emitting devices 100 (for example, the first light-emitting device 101) in the part close to the light-emitting layer 131 (for example, the second hole transport layer 1323) - the hole transport functional material HT, can form an exciton complex HT / HN with the second main material HN, and holes and electrons can recombine on the exciton complex HT / HN to form excitons.

[0124] For example, in the first light-emitting device 101, the process of forming excitons by recombining on the excited complex HP / HN formed by the first host material HP and the second host material HN, and transferring energy to the guest material D is shown in FIG7 ; the process of forming excitons by recombining on the excited complex HT / HN formed by the hole transport functional material HT and the second host material HN, and transferring energy to the guest material D is shown in FIG8 .

[0125] As can be seen from Figures 7 and 8, during the light-emitting process, the exciplex HT / HN formed by the hole transport functional material HT and the second host material HN, and the exciplex HP / HN formed by the first host material HP and the second host material HN, can achieve the same function. Specifically, on the exciplex HT / HN and the exciplex HP / HN, excitons can be recombined to produce excitons, and the excitons produced are, for example, at least one of singlet excitons and triplet excitons. Among them, the energy of the singlet exciton can be transferred to the guest material D through Dexter energy transfer, and the energy of the triplet exciton can be transferred to the guest material D through Forster energy transfer. It should be noted that in Figures 7 and 8, the lower frame edge of the box outside each material represents the highest occupied molecular orbital energy level HOMO of the material, and the upper frame edge represents the lowest unoccupied molecular orbital energy level LUMO of the material; the left frame edge and the right frame edge are for forming a closed schematic diagram and have no actual meaning. In Figures 7 and 8, the guest material D, the first host material HP, and the second host material HN are arranged on the left and right to more clearly illustrate the highest occupied molecular orbital energy level HOMO, the lowest unoccupied molecular orbital energy level LUMO, and the energy transfer process of the corresponding materials, but have no practical meaning.

[0126] In related technologies, the light emitted by a light-emitting diode (LED) is not of a single wavelength; rather, a specific wavelength has the highest intensity. Peak wavelength (WLP) refers to the wavelength at which the luminous intensity or radiant power on the emission spectrum reaches its maximum, also known as the wavelength of maximum power. This wavelength is measured in nanometers (nm). Peak wavelength reflects the spectral energy variation of a light source and is an important metric for determining the effective output wavelength of a luminescent material.

[0127] In some embodiments, the material of the hole transport functional layer 132 includes a hole transport functional material HT. The absolute value of the difference between the peak wavelength WLP(HP / HN) of the emission spectrum of the exciplex HP / HN formed by the first host material HP and the second host material HN and the peak wavelength WLP(HP / HN) of the emission spectrum of the exciplex HT / HN formed by the hole transport functional material HT and the second host material HN is less than or equal to 10 nm. In other words, |WLP(HP / HN)-WLP(HT / HN)|≤10 nm.

[0128] It can be understood that when the material of the light-emitting layer 131 of the light-emitting unit 13 includes a first host material HP, a second host material HN and a guest material D, during the light-emitting process of the light-emitting device 100, the peak wavelength WLP(HP / HN) of the emission spectrum of the excited complex HP / HN formed by the first host material HP and the second host material HN corresponds relatively highly to the peak wavelength WLP(D) of the absorption spectrum of the guest material D. In this way, when the excited complex HP / HN formed by the first host material HP and the second host material HN transfers energy to the guest material D, the energy transfer efficiency is relatively high.

[0129] When |WLP(HP / HN)-WLP(HT / HN)| is relatively large, the emission spectrum of the exciplex HT / HN formed by the hole-transporting material HT and the second host material HN differs significantly from the emission spectrum of the exciplex HP / HN formed by the first host material HP and the second host material HN. This results in relatively insufficient energy transfer from the exciplex HT / HN to the guest material D, which can easily lead to efficiency loss. When |WLP(HP / HN)-WLP(HT / HN)| ≤ 10 nm, the peak wavelength WLP(HT / HN) of the emission spectrum of the exciplex HT / HN formed by the hole-transporting material HT and the second host material HN is closer to the peak wavelength WLP(HP / HN) of the emission spectrum of the exciplex HP / HN formed by the first host material HP and the second host material HN. In this case, the correspondence between the peak wavelength WLP(HT / HN) of the emission spectrum of the excited complex HT / HN formed by the hole transport functional material HT and the second host material HN and the peak wavelength WLP(D) of the absorption spectrum of the guest material D can be improved. In this way, during the light-emitting process of the light-emitting device 100, the guest material D can not only receive the energy transmitted by the excited complex HP / HN formed by the first host material HP and the second host material HN, but also receive the energy transmitted by the excited complex HT / HN formed by the hole transport functional material HT and the second host material HN. The energy transmission efficiency can be effectively improved, the energy utilization rate can be improved, and the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101) can be effectively improved.

[0130] In some examples, the emission spectra of the exciplex HP / HN formed by the first host material HP and the second host material HN, and the emission spectra of the exciplex HT / HN formed by the hole transport material HT and the second host material HN are shown in Figure 13 . Here, ΔWLP refers to |WLP(HP / HN) - WLP(HT / HN)|. The ordinate in Figure 13 represents the normalized photoluminescence intensity, which is the photoluminescence intensity obtained by normalizing the photoluminescence intensity corresponding to the peak wavelength WLP to 1. It should be noted that the emission spectra shown in Figure 13 were measured using a fluorescence spectrometer, and the measured luminescence intensity is the photoluminescence intensity. Photoluminescence, as used herein, refers to the emission of new photons stimulated by the energy of light or photons. It is a non-contact, non-destructive measurement method. Essentially, an excitation photon reaches a sample and is absorbed, resulting in photoexcitation. This photoexcitation causes electrons to transition to an excited state, which then releases energy (photons) when they return to a lower energy level through vibrational relaxation. The light emitted by this process is photoluminescence.

[0131] In some embodiments, under a predetermined electric field strength, the electron mobility μ of the second host material HN is e (HN), and the hole mobility μ of the first host material HP h The ratio between (HP) is greater than or equal to 10 and less than or equal to 1000. The preset electric field strength is, for example, 5000 V / m (volts / meter). That is, the electron mobility μ of the second host material HN is e (HN), and the hole mobility μ of the first host material HP h (HP) satisfies:

[0132] It can be understood that when the electron mobility μ e (HN), and the hole mobility μ of the first host material HP h When the ratio between (HP) is greater than or equal to 10 and less than or equal to 1000, the electron mobility μ of the second host material HN is e (HN), much larger than the hole mobility μ of the first host material HP h In this way, in the light-emitting layer 131 of the light-emitting unit 13, the migration rate of holes is relatively slow, while the migration rate of electrons is relatively fast, which can increase the imbalance between electron and hole migration. In this case, the region where holes and electrons recombine to form excitons in the light-emitting layer 131 can be located on the side close to the hole transport functional layer 132 (such as the position K1 shown in Figure 9).

[0133] As shown in FIG10 , at the interface between the hole transport functional layer 132 (e.g., the second hole transport layer 1323) and the light-emitting layer 131, there are four materials: a first host material HP, a second host material HN, a guest material D, and a hole transport functional material HT. Furthermore, the first host material HP and the second host material HN can form an exciplex HP / HN, and the hole transport functional material HT and the second host material HN can form an exciplex HT / HN. Therefore, when the region where holes and electrons recombine to form excitons in the light-emitting layer 131 is located near the hole transport functional layer 132 (as shown at position K1 in FIG9 ), compared to the case where the region where holes and electrons recombine to form excitons is located in the middle of the light-emitting layer 131 (as shown at position K2 in FIG9 ), holes and electrons can recombine to form excitons not only on the exciplex HP / HN but also on the exciplex HT / HN. This improves energy utilization and the efficiency of the light-emitting device 100.

[0134] For example, under a preset electric field strength of 5000 V / m, the electron mobility μ of the second host material HN is e (HN), and the hole mobility μ of the first host material HP h The ratio between (HP) can be 10, 50, 100, 500 or 1000, etc.

[0135] In some embodiments, the absolute value of the difference between the highest occupied molecular orbital energy level HOMO(HP) of the first host material HP and the highest occupied molecular orbital energy level HOMO(D) of the guest material D is less than or equal to 0.4 eV; and the absolute value of the difference between the lowest unoccupied molecular orbital energy level LUMO(HN) of the second host material HN and the lowest unoccupied molecular orbital energy level LUMO(D) of the guest material D is less than or equal to 0.4 eV. That is, |HOMO(HP)-HOMO(D)|≤0.4 eV, and |LUMO(HN)-LUMO(D)|≤0.4 eV.

[0136] It can be understood that when |HOMO(HP)-HOMO(D)|≤0.4eV, and |HOMO(HP)-HOMO(D)| is relatively small, the absolute value of the difference between the highest occupied molecular orbital energy level HOMO(HP) of the first host material HP and the highest occupied molecular orbital energy level HOMO(D) of the guest material D is relatively small, which can make the hole transport performance relatively high, thus increasing the exciton yield and improving the luminous efficiency of the light-emitting device 100. When |HOMO(HP)-HOMO(D)|≤0.4eV, and |HOMO(HP)-HOMO(D)| is relatively large, the absolute value of the difference between the highest occupied molecular orbital energy level HOMO(HP) of the first host material HP and the highest occupied molecular orbital energy level HOMO(D) of the guest material D is relatively large, and accordingly, deeper hole traps are easily generated on the first host material HP. The hole transport layer 100 is a light emitting device 100 having a plurality of holes. The light emitting device 100 has a plurality of holes. The light emitting device 100 has a plurality of holes. The light emitting device 100 has a plurality of holes. The light emitting device 100 has a plurality of holes. The light emitting device 100 has a plurality of holes. The light emitting device 100 has a plurality of holes. The light emitting device 100 has a plurality of holes. The light emitting device 100 has a plurality of holes. The light emitting device 100 has a plurality of holes.

[0137] For example, the absolute value of the difference between the highest occupied molecular orbital energy level HOMO(HP) of the first host material HP and the highest occupied molecular orbital energy level HOMO(D) of the guest material D can be 0.1eV, 0.15eV, 0.2eV, 0.25eV or 0.4eV, etc.

[0138] For example, the absolute value of the difference between the lowest unoccupied molecular orbital energy level LUMO(HN) of the second host material HN and the lowest unoccupied molecular orbital energy level LUMO(D) of the guest material D can be 0.1eV, 0.15eV, 0.2eV, 0.3eV or 0.4eV, etc.

[0139] In some embodiments, the first host material is selected from any one of the structures represented by formula (I).

[0140] Wherein, R1 and R2 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted diphenylfluorenyl and substituted or unsubstituted spirofluorenyl.

[0141] L1 and L2 are the same or different and are independently selected from any one of a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group and a substituted or unsubstituted naphthylene group.

[0142] n1 and n2 are the same or different and are independently selected from any one of 0 and 1.

[0143] n3 and n6 are the same or different and are independently selected from any one of 0, 1, 2, 3 and 4.

[0144] n4 and n5 are the same or different and are independently selected from any one of 0, 1 and 2.

[0145] It should be noted that, in the structure shown in general formula (I), (D) nx , means that the number of deuterium (D) is nx. When nx is 0, it means that the substitution positions of the carbon atoms with substitution positions on the corresponding six-membered ring are all replaced by hydrogen atoms. When nx is z, and z is a positive integer greater than or equal to 1, it means that z deuteriums are connected to the corresponding six-membered ring; and the z deuteriums can be connected to any z carbon atoms with substitution positions among the six carbon atoms on the six-membered ring; here, there is no limitation on the position of the carbon atom connected to the deuterium. Wherein, x is any one of 3, 4, 5 and 6, and z is any value greater than or equal to 1 in the selection range of nx.

[0146] It should be noted that when R1 or R2 is selected from any one of a substituted phenyl group, a substituted biphenyl group, a substituted naphthyl group, a substituted carbazolyl group, a substituted dibenzofuranyl group, a substituted dibenzothiophenyl group, a substituted dimethylfluorenyl group, a substituted diphenylfluorenyl group and a substituted spirofluorenyl group, there is no limitation on the type and number of the substituents.

[0147] Among the above substituents, the structure of dimethylfluorenyl is, for example, The structure of diphenylfluorenyl is, for example, The structure of spirofluorenyl is, for example,

[0148] It should be noted that, in the general formula (I), It is a benzindolecarbazolyl group. Moreover, in the above general formula (I), the number n1 of L1 and the number n2 of L2 can be 0. When n1 is 0, the nitrogen in the benzindolecarbazolyl group and R1 are directly connected by a covalent bond (for example, a single bond). When n2 is 0, the nitrogen in the benzindolecarbazolyl group and R2 are directly connected by a covalent bond (for example, a single bond). In the general formula (I), L1 and L2 can be any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene and substituted or unsubstituted naphthylene. The structure of phenylene is introduced below. Phenyl refers to the general term for the remaining group after the hydrogen atom of one carbon atom on the benzene ring is removed. Phenylene refers to the general term for the remaining group after the hydrogen atoms on two carbon atoms on the benzene ring are removed. For the understanding of biphenylene and naphthylene, please refer to the above content and will not be repeated here. When L1 or L2 is a substituted phenylene group, a substituted biphenylene group, or a substituted naphthylene group, the type and number of the substituents are not limited.

[0149] It can be understood that the structure shown in the general formula (I) contains a benzindolecarbazole group, which can make the HOMO electron cloud have a higher distribution density on the structure of the benzindolecarbazole group. In this way, the first host material HP has a higher hole transport performance and can play the role of a hole-type host. In this way, during the light-emitting process of the light-emitting device 100, the first host material HP and the second host material HN can form an exciton complex HP / HN, transfer the exciton energy to the guest material D, achieve the purpose of emitting light, and improve the efficiency of the light-emitting device 100.

[0150] Moreover, when the light-emitting device 100 is the first light-emitting device 101, since the first light-emitting device 101 emits red light relative to other light-emitting devices 100 (for example, the second light-emitting device 102), the corresponding wavelength is relatively large and the corresponding energy is relatively low. When the first host material HP contains a planar group - a benzoindolecarbazole group, the molecular rigidity of the first host material HP is relatively high and the molecular orientation is relatively high, so that the triplet energy level T1 (HP) of the first host material HP is relatively low, and the matching with the second host material HN and the guest material D of the light-emitting layer 131 of the first light-emitting device 101 is relatively better. In this way, the efficiency of the first light-emitting device 101 can be improved.

[0151] In addition, in the above general formula (I), the substituent of the benzindolecarbazolyl group is deuterium (D), that is, deuteration is performed on the molecular fragment of the HOMO electron cloud distribution of the first host material HP. In this way, the thermal stability of the first host material HP can be improved, and the life of the light-emitting device 100 can be increased.

[0152] An exemplary structure of the first host material HP represented by the general formula (I) is described below.

[0153] In some examples, when R2 is a naphthyl group, the structural formula of the first host material HP can be as shown below.

[0154] In some examples, when R1 is a dibenzofuranyl group, the structural formula of the first host material HP can be as shown below.

[0155] In some examples, when R1 is a carbazole group, the structural formula of the first host material HP can be as shown below.

[0156] It should be noted that the above-listed structural formulas are examples of the structure of the first host material HP and are not intended to limit the first host material HP. Furthermore, (HP1-x) in the above structural formulas is a generic name for each structural formula and is not part of the structural formula itself, where x is a positive integer.

[0157] In some embodiments, the second host material is selected from any one of the structures represented by formula (II).

[0158] Wherein, L3, L4 and L5 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene, substituted or unsubstituted benzodibenzofuranylene, substituted or unsubstituted dibenzothiophenylene, substituted or unsubstituted benzodibenzothiophenylene, substituted or unsubstituted carbazolylene, substituted or unsubstituted benzocarbazolylene and substituted or unsubstituted phenanthroxazolyl.

[0159] R3, R4 and R5 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted benzodibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted benzodibenzothiophenyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted benzocarbazolyl and substituted or unsubstituted phenanthroxazolyl.

[0160] n7, n8 and n9 are the same or different and are independently selected from any one of 0 and 1.

[0161] It should be noted that the descriptions of n7, n8, and n9 here refer to the descriptions of n1 and n2 above and will not be repeated here. The phrase "n7, n8, and n9 are the same" refers to the situation where n7, n8, and n9 are the same. Except for the aforementioned situations, all other situations are different.

[0162] It should be noted that when L3, L4 or L5 is selected from any one of substituted phenylene, substituted biphenylene, substituted naphthylene, substituted dibenzofuranyl, substituted benzodibenzofuranyl, substituted dibenzothiophenylene, substituted benzodibenzothiophenylene, substituted carbazolyl, substituted benzocarbazolyl and substituted phenanthroxazolyl, and / or, R3, R4 and R5 are selected from any one of substituted phenyl, substituted biphenylene, substituted naphthyl, substituted dibenzofuranyl, substituted benzodibenzofuranyl, substituted dibenzothiophenylene, substituted carbazolyl, substituted benzocarbazolyl and substituted phenanthroxazolyl, the type and number of the substituents are not limited herein.

[0163] It is understood that the structure shown in the above general formula (II) contains a triazine group, that is, The LUMO electron cloud can be made to have a higher distribution density on the above-mentioned triazine-based structure, so that the second host material HN has higher electron transport performance and can play the function of an electronic host. In this way, during the light-emitting process of the light-emitting device 100, the first host material HP and the second host material HN can form an exciton complex HP / HN, transfer the exciton energy to the guest material D, achieve the purpose of emitting light, and improve the efficiency of the light-emitting device 100.

[0164] Moreover, when the light-emitting device 100 is the first light-emitting device 101, in the structure shown in the above general formula (II), the selection range of R3, R4 and R5 includes phenyl, biphenyl, naphthyl, dibenzofuranyl, benzodibenzofuranyl, dibenzothiophenyl, benzodibenzothiophenyl, carbazolyl, benzocarbazolyl and phenanthroxazolyl, and these substituents are all planar groups. These planar groups can make the triplet energy level T1(HN) of the second host material HN relatively low, and can reduce the triplet energy level T1(HN) of the second host material HN. Since the first light-emitting device 101 emits red light with a relatively smaller wavelength and a relatively higher energy compared to other light-emitting devices 100 (for example, the second light-emitting device 102), when the second host material HN includes the above-mentioned planar group, the triplet energy level T1(HN) of the second host material HN is relatively low, and the matching with the first host material HP and the guest material D of the light-emitting layer 131 of the first light-emitting device 101 is relatively better. In this way, the efficiency of the first light-emitting device 101 can be improved.

[0165] An exemplary structure of the second host material HN represented by the general formula (II) is described below.

[0166] In some examples, when one of R3, R4, and R5 is a deuterated naphthyl group, and the deuterated naphthyl group is connected to the triazine group via a single bond, the structural formula of the second host material HN can be as shown below.

[0167] In some examples, when one of R3, R4, and R5 is a deuterated naphthyl group, and the deuterated naphthyl group is connected to the triazine group through a deuterated phenylene group, the structural formula of the second host material HN can be shown as follows.

[0168] It should be noted that the above-listed structural formulas are examples of the structures of the second host material HN and are not intended to limit the second host material HN. Furthermore, (HN1-x) in the above structural formulas is a generic name for each structural formula and is not part of the structural formula itself, where x is a positive integer.

[0169] In some embodiments, the hole transport functional material is selected from any one of the structures represented by formula (III).

[0170] Wherein, L6, L7 and L8 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene and substituted or unsubstituted dibenzothiophenylene.

[0171] R6, R7 and R8 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted diphenylfluorenyl, substituted or unsubstituted spirofluorenyl and substituted or unsubstituted adamantyl.

[0172] n 10 、n 11 and n 12 are the same or different, and are independently selected from any one of 0 and 1.

[0173] It should be noted that here n 10 、n 11 and n 12 For the description of n7, n8 and n9, please refer to the above description; they will not be repeated here.

[0174] It should be noted that when L6, L7 and L8 are selected from any one of substituted phenylene, substituted biphenylene, substituted naphthylene, substituted dibenzofuranyl and substituted dibenzothiophenylene, and / or, R6, R7 and R8 are selected from any one of substituted phenyl, substituted biphenylene, substituted naphthyl, substituted dibenzofuranyl, substituted dibenzothiophenyl, substituted dimethylfluorenyl, substituted diphenylfluorenyl, substituted spirofluorenyl and substituted adamantyl, the type and number of the substituents are not limited here.

[0175] It can be understood that since L6, L7 and L8, as well as R6, R7 and R8 in the structure shown in the above general formula (III) are all aromatic groups, the hole transport functional material HT is a hole-type material of the triarylamine type, which can make the HOMO electron cloud of the hole transport functional material HT have a higher distribution density on the triarylamine structure. In this way, the hole transport functional material HT can be used to form the hole transport functional layer 132 of the light-emitting device 100, for example, to form the second hole transport layer 1323, to realize the function of transporting holes, and / or blocking electrons and excitons generated in the light-emitting layer 131.

[0176] Moreover, based on the structure shown in general formula (III), the hole transport functional material HT can form an exciplex HT / HN with the second host material HN. In this way, during the light-emitting process of the light-emitting device 100, the guest material D can not only receive the energy transmitted by the exciplex HP / HN formed by the first host material HP and the second host material HN, but also receive the energy transmitted by the exciplex HT / HN formed by the hole transport functional material HT and the second host material HN. The energy transmission efficiency can be effectively improved, the energy utilization rate can be improved, and the efficiency of the light-emitting device 100 can be effectively improved.

[0177] An exemplary structure of the hole transport functional material HT having the structure represented by the general formula (III) is described below.

[0178] In some examples, when at least one of R6, R7, and R8 is a dimethylfluorenyl group, the structural formula of the hole transport functional material HT may be as shown below.

[0179] It should be noted that the above-listed structural formulas are examples of the structures of hole-transporting materials HT and are not intended to limit the scope of such materials. Furthermore, (HT-x) in the above structural formulas, where x is a positive integer, is a designation for each structural formula and does not constitute a part of the structure.

[0180] In some embodiments, at least one of the first host material HP, the second host material HT, and the hole transport functional material HT is a deuterated material.

[0181] It should be noted that a deuterated material refers to a material in which at least one hydrogen atom in its structure is replaced by a deuterium atom. In other words, the structure of the deuterated material contains at least one deuterium atom.

[0182] Specifically, when the first host material HP is a deuterated material, the first host material HP satisfies at least one of the following four conditions: (1) n1 is 1, and L1 is selected from any one of deuterium-substituted phenylene, deuterium-substituted biphenylene and deuterium-substituted naphthylene; (2) n2 is 1, and L2 is selected from any one of deuterium-substituted phenylene, deuterium-substituted biphenylene and deuterium-substituted naphthylene; (3) at least one of n3, n4, n5 and n6 is greater than or equal to 1; (4) at least one of R1 and R2 is selected from any one of deuterium-substituted phenyl, deuterium-substituted biphenylene, deuterium-substituted naphthyl, deuterium-substituted carbazolyl, deuterium-substituted dibenzofuranyl, deuterium-substituted dibenzothiophenyl, deuterium-substituted dimethylfluorenyl, deuterium-substituted diphenylfluorenyl and deuterium-substituted spirofluorenyl.

[0183] When the second host material HN is a deuterated material, the second host material HN satisfies at least one of the following four conditions: (1) n7 is 1, and L3 is selected from deuterium-substituted phenylene, deuterium-substituted biphenylene, deuterium-substituted naphthylene, deuterium-substituted dibenzofuranylene, deuterium-substituted benzodibenzofuranylene, deuterium-substituted dibenzothiopheneylene, deuterium-substituted benzodibenzothiopheneylene, deuterium-substituted phenyl ... (2) n8 is 1, and L4 is selected from the group consisting of deuterium-substituted phenylene, deuterium-substituted biphenylene, deuterium-substituted naphthylene, deuterium-substituted dibenzofuranylene, deuterium-substituted benzodibenzofuranylene, deuterium-substituted dibenzothiopheneylene, deuterium-substituted benzodibenzothiopheneylene, deuterium-substituted carbazolyl, deuterium-substituted phenylene, deuterium-substituted biphenylene, deuterium-substituted naphthylene, deuterium-substituted dibenzofuranylene, deuterium-substituted dibenzothiopheneylene, deuterium-substituted benzodibenzothiopheneylene, deuterium-substituted carbazolyl, deuterium-substituted phenylene, deuterium-substituted biphenylene, deuterium-substituted naphthylene, deuterium-substituted dibenzofuranylene, deuterium-substituted dibenzothiopheneylene, deuterium-substituted benzodibenzothiopheneylene, deuterium-substituted phenyl ... any one of benzocarbazolyl and deuterium-substituted phenanthroxazolyl; (3) n9 is 1, and L5 is selected from deuterium-substituted phenylene, deuterium-substituted biphenylene, deuterium-substituted naphthylene, deuterium-substituted dibenzofuranyl, deuterium-substituted benzodibenzofuranyl, deuterium-substituted dibenzothienyl, deuterium-substituted benzodibenzothienyl, deuterium-substituted carbazolyl, deuterium-substituted benzocarbazolyl and deuterium-substituted (4) at least one of R3, R4 and R5 is selected from any one of deuterium-substituted phenyl, deuterium-substituted biphenyl, deuterium-substituted naphthyl, deuterium-substituted dibenzofuranyl, deuterium-substituted benzodibenzofuranyl, deuterium-substituted dibenzothiopheneyl, deuterium-substituted benzodibenzothiopheneyl, deuterium-substituted carbazolyl, deuterium-substituted benzocarbazolyl and deuterium-substituted phenanthroxazolyl.

[0184] When the hole transport functional material HT is a deuterated material, the hole transport functional material HT satisfies at least one of the following four conditions: (1) n10 is 1, and L6 is selected from any one of deuterium-substituted phenylene, deuterium-substituted biphenylene, deuterium-substituted naphthylene, deuterium-substituted dibenzofuranylene and deuterium-substituted dibenzothiophenylene; (2) n 11 is 1, and L7 is selected from any one of deuterium-substituted phenylene, deuterium-substituted biphenylene, deuterium-substituted naphthylene, deuterium-substituted dibenzofuranylene and deuterium-substituted dibenzothiophenylene; (3) n 12 is 1, and L8 is selected from any one of deuterium-substituted phenylene, deuterium-substituted biphenylene, deuterium-substituted naphthylene, deuterium-substituted dibenzofuranylene and deuterium-substituted dibenzothiophenylene; (4) at least one of R3, R4 and R5 is selected from any one of deuterium-substituted phenyl, deuterium-substituted biphenylene, deuterium-substituted naphthylene, deuterium-substituted dibenzofuranylene, deuterium-substituted dibenzothiophenylene, deuterium-substituted dimethylfluorenylene, deuterium-substituted diphenylfluorenylene, deuterium-substituted spirofluorenylene and deuterium-substituted adamantylene.

[0185] The deuterium-substituted phenylene group refers to a phenylene group in which at least one hydrogen atom is replaced by a deuterium atom. For understanding of deuterium-substituted biphenylene and deuterium-substituted naphthyl, etc., please refer to the above content and will not be repeated here.

[0186] When the region where holes and electrons recombine to form excitons in the light-emitting layer 131 of the light-emitting device 100 (for example, the first light-emitting device 101) is located on a side close to the hole transport functional layer 132 (for example, the second hole transport layer 1323) (such as the K1 position shown in Figure 9), the exciton density is relatively high at the interface between the hole transport functional layer 132 (for example, the second hole transport layer 1323) and the light-emitting layer 131, which causes the guest material D, the first host material HP, the second host material HT and the hole transport functional material HT to be easily degraded, thereby reducing the device life.

[0187] It is understood that since the atomic weight of deuterium is twice that of hydrogen, by providing at least one of the first host material HP, the second host material HT, and the hole transport functional material HT as a deuterated material, the physical properties of the material of the light-emitting layer 131 of the light-emitting device 100 (e.g., the first light-emitting device 101) and / or the material of the hole transport functional layer 132 (e.g., the second hole transport layer 1323) will change. Specifically, when the first host material HP and the second host material HT are substituted with deuterium, and / or the hole transport functional material HT is substituted with deuterium, molecular vibration can be effectively suppressed, bond lengths can be reduced, and the molecular exciton stability can be improved, thereby improving molecular stability. In this way, the thermal stability of the material of the light-emitting layer 131 of the light-emitting device 100 (e.g., the first light-emitting device 101) and / or the material of the hole transport functional layer 132 (e.g., the second hole transport layer 1323) is improved, which can increase the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0188] In some examples, the first host material HP, the second host material HT, and the hole transport functional material HT are all deuterated materials. This improves the thermal stability of the material of the light-emitting layer 131 and the material of the hole transport functional layer 132 (e.g., the second hole transport layer 1323) of the light-emitting device 100 (e.g., the first light-emitting device 101), thereby increasing the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0189] In some embodiments, a mass ratio between the first host material HP and the second host material HN is greater than or equal to 3:7 and less than or equal to 1:1.

[0190] It should be noted that the mass ratio between the first host material HP and the second host material HN is greater than or equal to 3:7 and less than or equal to 1:1, which means that the mass m of the first host material HP is greater than or equal to 3:7 and less than or equal to 1:1. HP , and the mass m of the second host material HN HN , satisfied with there.

[0191] It can be understood that when the mass ratio between the first main material HP and the second main material HN is greater than or equal to 3:7 and less than or equal to 1:1, the mass ratio between the first main material HP and the second main material HN is reasonable, which can make the electron transmission rate and the hole transmission rate in the light-emitting device 100 (for example, the first light-emitting device 101) relatively balanced, and the exciton yield can be increased. In this way, the energy utilization rate can be relatively high, and the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101) can be improved.

[0192] Exemplarily, the mass ratio between the first host material HP and the second host material HN is 3:7, 4:6, 3:4, 4:5 or 1:1, etc.

[0193] The above is an exemplary introduction to the materials for the light-emitting layer 131 and the hole transport layer 132 when the first host material HP contains a benzindolecarbazole group. This material system can improve the efficiency and lifespan of the light-emitting device 100, for example, the first light-emitting device 101. The following is an exemplary introduction to the materials for the light-emitting layer 131 when the first host material HP contains a triarylamine structure.

[0194] In some implementations, triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ) are prone to occur in the exciton recombination region of the light-emitting layer 131 of the light-emitting device 100 (e.g., the first light-emitting device 101), resulting in a reduction in the number of excitons. Furthermore, the triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ) phenomena are more severe at high current densities (high grayscales), causing the luminous efficiency at high current densities (high grayscales) to be lower than that at low current densities (low grayscales), resulting in efficiency roll-off at high current densities.

[0195] In the above implementation, the region where triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ) occur is, for example, a region near the hole transport functional layer 132. In this case, the normalized exciton intensity at various positions along the second direction Y in the light-emitting layer 131 is, for example, as shown in FIG11 . The normalized exciton intensity in FIG11 refers to the exciton intensity at the measurement point corresponding to the highest exciton intensity normalized to 1. As can be seen from FIG11 , the exciton intensity is relatively high on the side of the light-emitting layer 131 near the hole transport functional layer 132, compared to the middle position of the light-emitting layer 131 and the position of the light-emitting layer 131 near the electron transport functional layer 133.

[0196] In related art, efficiency decay can be characterized by an efficiency decay index ΔE. The efficiency decay index ΔE refers to the absolute value of the difference between the normalized current efficiency E1′ of the light-emitting device 100 at a first preset current density I1 and the normalized current efficiency E2′ of the light-emitting device 100 at a second preset current density I2. The normalized current efficiency E1′ of the light-emitting device 100 at the first preset current density I1 refers to the ratio of the current efficiency E1 at the first preset current density I1 to the maximum current efficiency Max(E1, E2), that is:

[0197] The normalized current efficiency E2′ of the light emitting device 100 at the second preset current density I2 refers to the ratio of the current efficiency E2 at the second preset current density I2 to the maximum current efficiency Max(E1, E2), that is:

[0198] Among them, the maximum current efficiency Max(E1,E2) refers to the maximum of the corresponding current efficiencies when the current density is in the range of [I1,I2]. The method for obtaining the maximum current efficiency Max(E1,E2) is, for example, to obtain a curve graph of the change of current efficiency E with current density I by measuring, and reading the highest point of the corresponding curve segment when the current density is in the range of [I1,I2]. The current efficiency corresponding to the highest point is the maximum current efficiency Max(E1,E2). It should be noted that the current density in the range of [I1,I2] includes the cases when the current density is I1 and the current density is I2.

[0199] For example, the first preset current density I1 refers to a current density of 1 mA / cm 2 The second preset current density I2 refers to a current density of 15mA / cm 2 .

[0200] In some embodiments, the first host material is selected from any one of the structures represented by formula (IV);

[0201] Wherein, L9 is selected from any one of a single bond, a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group.

[0202] Ar1 and Ar2 are fused; Ar1 ​​and Ar2 share two carbon atoms, which are X a and X b , and, X a and X b Any two adjacent ones among X1, X2, X3, X4 and X5.

[0203] Among X1, X2, X3, X4 and X5, except X a and X b The remaining three are independently selected from N and C (R a ) in any one of the following. Wherein, N is nitrogen, C(R a ) is a substituted or unsubstituted carbon.

[0204] R a Any one selected from hydrogen and deuterium.

[0205] Ar1 is selected from any one of Ar1-a to Ar1-i.

[0206] Y is selected from O, S, Se, C=O, S(=O)2, C(R b R c )、Si(R d R e )、N(R f )、P(R g )、P(=O)(R h ) and B(R i ) in any one of the following.

[0207] R9, R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 、R 29 、R b 、R c 、R d 、R e 、R f 、R g 、R h and R i and n is an integer from 1 to 4. The substituents may be the same or different and independently selected from any one of hydrogen, tritium, halogen, nitrile, nitro, hydroxyl, carbonyl, ester, imide, amide, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted alkylthio, substituted or unsubstituted arylthio, substituted or unsubstituted alkylsulfonyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted alkenyl, substituted or unsubstituted silyl, substituted or unsubstituted boron, substituted or unsubstituted amine, substituted or unsubstituted arylphosphino, substituted or unsubstituted phosphinyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and substituted or unsubstituted heterocyclic group, or may be linked to adjacent substituents to form a substituted or unsubstituted ring.

[0208] n 13 、n 16 、n 18 、n 20and n 22 are the same or different and are independently selected from any one of 0, 1 and 2.

[0209] n 14 、n 15 、n 17 、n 19 、n 21 and n 23 The same or different, each independently selected from any one of 0, 1, 2, 3 and 4.

[0210] In the above general formula (IV), L9 can be a single bond. When L9 is a single bond, the nitrogen of the triarylamine structure and Ar2 are directly connected by a covalent bond. Moreover, L9 can be any one of a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group; wherein, the alkylene group of Cx refers to an alkylene group having a total of x carbon (C) atoms, where x is a positive integer, and the same applies hereinafter. For understanding other arylene groups such as Cx, please refer to the above content and will not be repeated here. For understanding alkylene, arylene, and heteroarylene groups, please refer to the above content of phenylene and will not be repeated here. When L9 is any one of a substituted C1-C30 alkylene group, a substituted C6-C30 arylene group, and a substituted C6-C30 heteroarylene group, the type and number of substituents are not limited here.

[0211] In the above general formula (IV), Ar1 and Ar2 are fused; Ar1 ​​and Ar2 share two carbon atoms, which are X a and X b That is, Ar1 and Ar2 share two carbon atoms X a and X b Ar2 is a six-membered ring formed by X1, X2, X3, X4, X5 and carbon number 1.

[0212] Among them, X a and X b Any two adjacent numbers among X1, X2, X3, X4 and X5; any two adjacent numbers among X1, X2, X3, X4 and X5 except X a and X b The remaining three are independently selected from N and C (R a ); including the following four situations:

[0213] (1)X a and X b X1 and X2; and X3, X4 and X5 are independently selected from N and C (R a ) in any one of the following.

[0214] (2)Xa and X b X2 and X3; and X1, X4 and X5 are independently selected from N and C (R a ) in any one of the following.

[0215] (3)X a and X b are X3 and X4; and X1, X2 and X5 are independently selected from N and C(R a ) in any one of the following.

[0216] (4)X a and X b are X4 and X5; and X1, X2 and X3 are independently selected from N and C (R a ) in any one of the following.

[0217] In the above general formula (IV), Y is selected from O, S, Se, C=O, S(=O)2, C(R b R c )、Si(R d R e )、N(R f )、P(R g )、P(=O)(R h ) and B(R i ) in which O is oxygen; S is sulfur; Se is selenium; C=O is a carbonyl group; S(=O)2 is a sulfone group; C(R b R c ) is substituted or unsubstituted carbon; Si(R d R e ) is substituted or unsubstituted silicon; N(R f ) is substituted or unsubstituted nitrogen; P(R g ) is substituted or unsubstituted phosphorus; P(=O)(R h ) is a substituted or unsubstituted phosphoryl group; B(R i ) is substituted or unsubstituted boron.

[0218] When R9, R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26、R 27 、R 28 、R 29 、R b 、R c 、R d 、R e 、R f 、R g 、R h and R i When the substituent is selected from any one of a substituted alkyl group, a substituted cycloalkyl group, a substituted alkoxy group, a substituted aryloxy group, a substituted alkylthio group, a substituted arylthio group, a substituted alkylsulfonyl group, a substituted arylsulfonyl group, a substituted alkenyl group, a substituted silyl group, a substituted boron group, a substituted amino group, a substituted arylphosphino group, a substituted phosphine group, a substituted aryl group, a substituted heteroaryl group, and a substituted heterocyclic group, the type and number of the substituent are not limited herein.

[0219] It should be noted that R9, R 10 、R 11 、R 12 and R 13 In the example, two adjacent R may be bonded to form a ring or not; 14 、R 15 、R 16 、R 17 and R 18 In the case of n, two adjacent pairs can be bonded to form a ring or not; 13 When the value is 2, the two R 19 It can be bonded to form a ring or not; in n 14 When the value of two adjacent R 20 It can be bonded to form a ring or not; in n 15 When the value of two adjacent R 21 It can be bonded to form a ring or not; in n 16 When the value is 2, the two R 22 It can be bonded to form a ring or not; in n 17 When the value of two adjacent R 23 It can be bonded to form a ring or not; in n 18 When the value is 2, the two R 24 It can be bonded to form a ring or not; in n 19 When the value of two adjacent R 25 It can be bonded to form a ring or not; in n 20 When the value is 2, the two R 26 It can be bonded to form a ring or not; in n21 When the value of two adjacent R 27 It can be bonded to form a ring or not; in n 22 When the value is 2, the two R 28 It can be bonded to form a ring or not; in n 23 When the value of two adjacent R 29 They may or may not be bonded to form a ring.

[0220] It should be noted that in the structure shown in general formula (IV), (Ry) nx , means that the number of Ry is nx. When nx is 0, it means that the substitution positions of the carbon atoms with substitution positions on the corresponding six-membered ring are all replaced by hydrogen atoms. When nx is z, and z is a positive integer greater than or equal to 1, it means that z Ry are connected to the corresponding six-membered ring; and, the z Ry can be connected to any z carbon atoms with substitution positions among the six carbon atoms on the six-membered ring; and, the z Ry can be the same or different. Here, there is no limitation on the position of the carbon atom connected to Ry. Wherein, x is any one of 13 to 23, y is any one of 19 to 29, and z is any one of the values ​​greater than or equal to 1 in the selection range of nx.

[0221] In the above general formula (IV), Ar1 is selected from any one of Ar1-a to Ar1-i. a and X b The structural formula of Ar1 and Ar2 after fusion is introduced when Ar1 is X3 and X4. a and X b For the understanding of the structure of Ar1 and Ar2 after fusion except X3 and X4, please refer to the above content, which will not be repeated here. a and X b When X3 and X4 are present, the structural formula after Ar1 and Ar2 are fused is as shown below.

[0222] It can be understood that since Ar2, Ar3 and Ar4 are all aromatic groups in the structure shown in the general formula (IV), the first host material HP is a hole-type material of the triarylamine type, which can make the HOMO electron cloud of the first host material HP have a higher distribution density on the triarylamine structure. In this way, firstly, the hole mobility of the first host material HP can be improved, and the exciton recombination region of the light-emitting layer 131 of the light-emitting device 100 (for example, the first light-emitting device 101) can be moved to the middle position of the light-emitting layer 131, which can balance the carrier distribution, reduce the probability of triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ), reduce exciton quenching, and slow down the problem of efficiency roll-off at high current density. Secondly, the first host material HP and the second host material HN can form an exciton complex HP / HN to generate more excitons, and transfer the exciton energy to the guest material D (for example, a phosphorescent material) to achieve the purpose of emitting light, thereby improving the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101).

[0223] To verify the hole transport performance of the first host material HP, a comparative material was designed and its HOMO electron cloud distribution was calculated. The results are shown in Figure 12. The comparative material's structural formula consists of a triarylamine molecule on one side (as shown on the left side of Figure 12) and an indolocarbazole molecule on the other side (as shown on the right side). Furthermore, the triarylamine and indolocarbazole molecules are connected by an alkyl group to interrupt any conjugation between the triarylamine and indolocarbazole structures. The HOMO electron cloud distribution was calculated using Gaussian calculation software using the density functional theory B3LYP / 6-31G(d) method and optimizing the ground-state structure of the molecule.

[0224] Figure 12 shows that in the comparative materials containing triarylamine and indolecarbazole molecular fragments, the HOMO electron cloud distribution is primarily concentrated on the triarylamine side. This indicates that the triarylamine has a stronger electron-donating ability than the indolecarbazole. This indicates that the first host material HP containing a triarylamine structure exhibits significantly higher hole transport performance than the hole-forming material containing an indolecarbazole structure. Consequently, the hole mobility is also significantly higher.

[0225] An exemplary structure of the first host material HP represented by general formula (IV) is described below.

[0226] In some examples, when Ar1 is Ar1-a, the structural formula of the first host material HP may be as shown below.

[0227] In some examples, when Ar1 is Ar1-b, the structural formula of the first host material HP may be as shown below.

[0228] In some examples, when Ar1 is Ar1-c, the structural formula of the first host material HP may be as shown below.

[0229] In some examples, when Ar1 is Ar1-d, the structural formula of the first host material HP may be as shown below.

[0230] In some examples, when Ar1 is Ar1-e, the structural formula of the first host material HP may be as shown below.

[0231] In some examples, when Ar1 is Ar1-f, the structural formula of the first host material HP may be as shown below.

[0232] In some examples, when Ar1 is Ar1-g, the structural formula of the first host material HP may be as shown below.

[0233] In some examples, when Ar1 is Ar1-h, the structural formula of the first host material HP may be as shown below.

[0234] In some examples, when Ar1 is Ar1-i, the structural formula of the first host material HP may be as shown below.

[0235] It should be noted that the above-listed structural formulas are examples of the structure of the first host material HP and are not intended to limit the first host material HP. Furthermore, (HP2-x) in the above structural formulas is a generic name for each structural formula and is not part of the structural formula itself, where x is a positive integer.

[0236] In some embodiments, R9, R 10 、R 11 、R 12 and R 13 In the , every two adjacent pairs form a group, and at least one group is bonded to form a ring.

[0237] It is understandable that when R9, R 10 、R 11 、R 12 and R 13When two adjacent bonds form a ring, Ar3 can fuse with the bonded ring. This creates a larger planar group at Ar3 in the first host material HP, increasing the molecular rigidity of the first host material HP. This reduces the triplet energy level T1(HP) of the first host material HP and minimizes the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0238] In some embodiments, R 14 、R 15 、R 16 、R 17 and R 18 In the , every two adjacent pairs form a group, and at least one group is bonded to form a ring.

[0239] It is understandable that when R 14 、R 15 、R 16 、R 17 and R 18 When two adjacent bonds form a ring, Ar4 can condense with the bonded ring. This creates a larger planar group at Ar4 in the first host material HP, increasing the molecular rigidity of the first host material HP. This reduces the triplet energy level T1(HP) of the first host material HP and minimizes the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0240] In some embodiments, 13 When the value is 2, the two R 19 Bond to form a ring.

[0241] It is understandable that when n 13 is 2 and two R 19 When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0242] In some embodiments, 14 When it is greater than or equal to 2, every two adjacent R 20 As a group, at least one group is bonded to form a ring.

[0243] It is understandable that when n 14 Two adjacent Rs greater than or equal to 2 20 When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0244] In some embodiments, 15 When it is greater than or equal to 2, every two adjacent R 21 As a group, at least one group is bonded to form a ring.

[0245] It is understandable that when n 15 Two adjacent Rs greater than or equal to 2 21 When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0246] In some embodiments, 16 When the value is 2, the two R 22 Bond to form a ring.

[0247] It is understandable that when n 16 is 2 and two R 22When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0248] In some embodiments, 17 When it is greater than or equal to 2, every two adjacent R 23 As a group, at least one group is bonded to form a ring.

[0249] It is understandable that when n 17 Two adjacent Rs greater than or equal to 2 23 When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0250] In some embodiments, 18 When the value is 2, the two R 24 Bond to form a ring.

[0251] It is understandable that when n 18 is 2 and two R 24 When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0252] In some embodiments, 19 When it is greater than or equal to 2, every two adjacent R 25 As a group, at least one group is bonded to form a ring.

[0253] It is understandable that when n 19 Two adjacent Rs greater than or equal to 2 25 When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0254] In some embodiments, 20 When the value is 2, the two R 26 Bond to form a ring.

[0255] It is understandable that when n 20 is 2 and two R 26 When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0256] In some embodiments, 21 When it is greater than or equal to 2, every two adjacent R 27 As a group, at least one group is bonded to form a ring.

[0257] It is understandable that when n 21 Two adjacent Rs greater than or equal to 2 27 When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0258] In some embodiments, 22When the value is 2, the two R 28 Bond to form a ring.

[0259] It is understandable that when n 22 is 2 and two R 28 When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0260] In some embodiments, 23 When it is greater than or equal to 2, every two adjacent R 29 As a group, at least one group is bonded to form a ring.

[0261] It is understandable that when n 23 Two adjacent Rs greater than or equal to 2 29 When bonding to form a ring, Ar1 can be fused with the bonded ring. This allows for a larger planar group to form at Ar1 in the first host material HP, resulting in relatively high molecular rigidity. This can lower the triplet energy level T1(HP) of the first host material HP and minimize the difference between the triplet energy level T1(HP) of the first host material HP and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0262] In the related art, the C-N single bond in a triarylamine structure has a relatively low bond dissociation energy compared to the C-N single bond in a carbazole structure and the C-C single bond in a biphenyl structure, resulting in relatively poor stability of the triarylamine structure. For example, as shown in the following formula, the C-N single bond in a triarylamine structure has a bond dissociation energy of 3.31 eV, the C-N single bond in a carbazole structure has a bond dissociation energy of 3.71 eV, and the C-C single bond in a biphenyl structure has a bond dissociation energy of 5.03 eV.

[0263] In the above-mentioned first host material HP, the triarylamine molecular fragment is the main area of ​​HOMO electron cloud distribution. Moreover, the first host material HP plays a major role in the hole injection and transmission process of the light-emitting layer 131, so that the stability of the triarylamine molecular fragment has a very important influence on the stability and life of the light-emitting device 100.

[0264] In order to improve the stability of the triarylamine molecular fragment in the first host material HP, in some embodiments, R9, R 10 、R 11 、R 12 and R 13 At least one of them is deuterium. 14 、R 15 、R 16 、R 17 and R 18 In the case where L9 is a single bond, at least one of X1, X2, X3, X4, and X5 is a deuterated carbon. When L9 is selected from any one of a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group, L9 is a deuterated group.

[0265] It should be noted that a deuterated group refers to a group in which at least one hydrogen atom in its structure is replaced by a deuterium atom. In other words, the structure of the deuterated group contains at least one deuterium atom.

[0266] It is understandable that when R9, R 10 、R 11 、R 12 and R 13 When at least one of them is deuterium, Ar3 is a six-membered ring substituted with deuterium. 14 、R 15 、R 16 、R 17 and R 18 When at least one of X1, X2, X3, X4 and X5 is a deuterated carbon, Ar2 is a deuterated six-membered ring. Moreover, when L9 is a single bond, in the structure of the first host material HP, the three parts directly connected to the nitrogen of the triarylamine structure are Ar3, Ar4 and Ar2 respectively. When L9 is selected from any one of a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group and a substituted or unsubstituted C6-C30 heteroarylene group (that is, when L9 is not a single bond), the three parts directly connected to the nitrogen of the triarylamine structure are Ar3, Ar4 and L9 respectively. Therefore, through the above arrangement, in the structure of the first host material HP, the three parts directly connected to the nitrogen of the triarylamine structure are all deuterated structures.

[0267] Since the atomic weight of deuterium is twice that of hydrogen, by setting up the three parts directly connected to the nitrogen of the triarylamine structure as deuterated structures, the molecular vibration at the position of the nitrogen of the triarylamine structure in the structure of the first host material HP can be effectively suppressed, and the stability of single bond a, single bond b, and single bond c in the structure shown in general formula (IV) can be improved, so that the molecular stability of the triarylamine structure is improved. In this way, the thermal stability of the first host material HP can be improved, and the life of the light-emitting device 100 can be increased.

[0268] In some embodiments, when L9 is a single bond, the ratio of the number of deuterium atoms and the number of hydrogen atoms to the total number of deuterium atoms in Ar3, Ar4, and Ar2 is greater than or equal to 50%. When L9 is selected from any one of a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group, the ratio of the number of deuterium atoms and the number of hydrogen atoms to the total number of deuterium atoms in Ar3, Ar4, and L9 is greater than or equal to 50%.

[0269] That is, when L9 is a single bond, the number of hydrogen atoms in Ar3 is N H-Ar3 , the number of deuterium in Ar3 N D-Ar3 , the number of hydrogen atoms in Ar4 is N H-Ar4 , the number of deuterium in Ar4 N D-Ar4 , the number of hydrogen atoms in Ar2 is N H-Ar2 and the number of deuterium in Ar2, N D-Ar2 , satisfying:

[0270] When L9 is selected from any one of substituted or unsubstituted C1-C30 alkylene, substituted or unsubstituted C6-C30 arylene and substituted or unsubstituted C6-C30 heteroarylene, the number of hydrogen atoms N in Ar3 is H-Ar3 , the number of deuterium in Ar3 N D-Ar3 , the number of hydrogen atoms in Ar4 is N H-Ar4 , the number of deuterium in Ar4 N D-Ar4 , the number of hydrogens in L9 N H-L9 and the number of deuterium in L9, N D-L9 , satisfying:

[0271] It can be seen that through the above configuration, in the structure of the first host material HP, in the three parts directly connected to the nitrogen of the triarylamine structure, the ratio between the number of hydrogen and the sum of the number of hydrogen and deuterium is greater than or equal to 50%.

[0272] It can be understood that, among the three parts directly connected to the nitrogen of the triarylamine structure, when the ratio of the number of deuterium and the number of hydrogen to the total number of deuterium is greater than or equal to 50%, compared with the case where the ratio of the number of deuterium and the number of hydrogen to the total number of deuterium is less than 50%, the deuterium content on the triarylamine molecular fragment in the first host material HP is relatively high. In this way, the suppression effect of the molecular vibration at the nitrogen position of the triarylamine structure is relatively better, so that the stability of single bond a, single bond b, and single bond c is relatively higher, and the molecular stability of the triarylamine structure is relatively higher. In this way, the thermal stability of the first host material HP can be effectively improved, and the life of the light-emitting device 100 can be increased.

[0273] Here, we take Ar3 as an example to explain the counting method of the number of hydrogen and deuterium. x When it is a non-planar group, R x The hydrogen in Ar3 forms part of the hydrogen in R x The number of hydrogen atoms in R is cumulatively counted into the number of hydrogen atoms in Ar3; x The deuterium in Ar3 forms part of the deuterium in R x The number of deuterium in is accumulated and counted into the number of deuterium in Ar3. x When it is a planar group, R x The hydrogen in does not form part of the hydrogen in Ar3, that is, R x The number of hydrogens in R is cumulative and not included in the number of hydrogens in Ar3; x The deuterium in does not form part of the deuterium in Ar3, that is, R x The number of deuterium in is cumulative and not included in the number of deuterium in Ar3. x R9, R 10 、R 11 、R 12 and R 13 It should be noted that the planar group refers to an M-membered ring group, where M is a positive integer greater than or equal to 3. For understanding the counting method of the number of hydrogen atoms and the number of deuterium atoms in Ar2, Ar4 and L9, reference can be made to the above content and will not be repeated here.

[0274] In some examples, when L9 is a single bond, the ratio of the number of deuterium atoms and the total number of hydrogen atoms to the total number of deuterium atoms in Ar3, Ar4, and Ar2 is greater than or equal to 70%. When L9 is selected from any one of a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group, the ratio of the number of deuterium atoms and the total number of hydrogen atoms to the total number of deuterium atoms in Ar3, Ar4, and L9 is greater than or equal to 70%.

[0275] For example, when L9 is a single bond, the ratio of the number of deuterium and the total number of hydrogen to deuterium in Ar3, Ar4 and Ar2 can be 50%, 60%, 75%, 80%, 90% or 100%, etc.

[0276] Illustratively, when L9 is selected from any one of a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group, the number of deuterium groups in Ar3, Ar4, and L9, and the ratio between the number of hydrogen groups and the total number of deuterium groups, can be 50%, 65%, 75%, 80%, 95%, or 100%, etc.

[0277] In some embodiments, the second host material is selected from any one of the structures represented by formula (V).

[0278] Among them, L 10 Any one selected from a single bond, a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group.

[0279] X6, X7, X8, X9 and X 10 the same or different, independently selected from N and C(R j ) in any one of the following. Wherein, N is nitrogen, C(R j ) is a substituted or unsubstituted carbon.

[0280] R j Any one selected from hydrogen, deuterium, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C6-C30 heteroaryl group, or may be linked with an adjacent substituent to form a substituted or unsubstituted ring.

[0281] R 30 and R 31 and n is an integer from 1 to 4. The substituents may be the same or different and independently selected from any one of hydrogen, tritium, halogen, nitrile, nitro, hydroxyl, carbonyl, ester, imide, amide, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted alkylthio, substituted or unsubstituted arylthio, substituted or unsubstituted alkylsulfonyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted alkenyl, substituted or unsubstituted silyl, substituted or unsubstituted boron, substituted or unsubstituted amine, substituted or unsubstituted arylphosphino, substituted or unsubstituted phosphinyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and substituted or unsubstituted heterocyclic group, or may be linked to adjacent substituents to form a substituted or unsubstituted ring.

[0282] n 24 and n 25 The same or different, each independently selected from any one of 0, 1, 2, 3, 4 and 5.

[0283] It should be noted that when X6, X7, X8, X9 and X 10 In the example, the two adjacent ones are C(R j ) In the case of two R j It can be bonded to form a ring or not; in n 24 When the value of two adjacent R 30 It can be bonded to form a ring or not; in n 25 When the value of two adjacent R 31 They may or may not be bonded to form a ring.

[0284] It should be noted that here L 10 The description of L9 can refer to the description of Cx above; the description of Cx here can refer to the description of Cx above, x is a positive integer; the description of arylene here can refer to the description of phenylene above; 24 and n 25 The description of n can be found in the above 19 description; no further description is given here.

[0285] It should be noted that when L 10 Any one selected from substituted C1-C30 alkylene, substituted C6-C30 arylene and substituted C6-C30 heteroarylene, and / or R j Any one selected from substituted C6-C30 arylene groups and substituted C6-C30 heteroarylene groups, and / or R 30 and R 31 When the substituent is selected from any one of a substituted alkyl group, a substituted cycloalkyl group, a substituted alkoxy group, a substituted aryloxy group, a substituted alkylthio group, a substituted arylthio group, a substituted alkylsulfonyl group, a substituted arylsulfonyl group, a substituted alkenyl group, a substituted silyl group, a substituted boron group, a substituted amino group, a substituted arylphosphino group, a substituted phosphine group, a substituted aryl group, a substituted heteroaryl group, and a substituted heterocyclic group, the type and number of the substituent are not limited herein.

[0286] It is understood that the structure shown in the above general formula (V) contains a triazine group, that is, The LUMO electron cloud can be made to have a higher distribution density on the above-mentioned triazine-based structure, so that the second host material HN has higher electron transport performance and can play the function of an electronic host. In this way, during the light-emitting process of the light-emitting device 100, the first host material HP and the second host material HN can form an exciton complex HP / HN, which transfers the exciton energy to the guest material D (for example, a phosphorescent material) to achieve the purpose of emitting light, thereby improving the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101).

[0287] Furthermore, when the light-emitting device 100 is the first light-emitting device 101, in the structure represented by the general formula (V), Ar5, Ar6, and Ar7 are all planar groups. These planar groups can make the triplet energy level T1(HN) of the second host material HN relatively low, thereby reducing the triplet energy level T1(HN) of the second host material HN. Since the first light-emitting device 101 emits red light, which has a relatively shorter wavelength and a relatively higher energy than other light-emitting devices 100 (e.g., the second light-emitting device 102), when the second host material HN includes the planar groups, the triplet energy level T1(HN) of the second host material HN is relatively low, resulting in a relatively better match with the first host material HP and the guest material D of the light-emitting layer 131 of the first light-emitting device 101. Thus, the efficiency of the first light-emitting device 101 can be improved.

[0288] In some embodiments, when X6, X7, X8, X9 and X 10 In the example, every two adjacent pairs form a group, and at least two pairs in a group are C(R j ) In the case of two R j Bond to form a ring.

[0289] It is understandable that when X6, X7, X8, X9 and X 10 Two adjacent C(R j ) are bonded to form a ring, Ar7 can be fused with the bonded ring. This can form a larger planar group at Ar7 of the second host material HN, making the molecular rigidity of the second host material HN relatively high. In this way, the triplet energy level T1(HN) of the second host material HN can be relatively low, and the difference between the triplet energy level T1(HN) of the second host material HN and the triplet energy level T1(D) of the guest material D can be relatively small, thereby improving energy transfer efficiency and enhancing the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0290] In some embodiments, 24 When it is greater than or equal to 2, every two adjacent R 30 As a group, at least one group is bonded to form a ring.

[0291] It is understandable that when n 24 Greater than or equal to 2, and two adjacent R 30 When the bonds form a ring, Ar5 can condense with the bonded ring. This allows for a larger planar group to form at Ar5 of the second host material HN, resulting in relatively high molecular rigidity. This allows for a relatively low triplet energy level T1(HN) of the second host material HN, minimizing the difference between the triplet energy level T1(HN) of the second host material HN and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0292] In some embodiments, 25 When it is greater than or equal to 2, every two adjacent R 31 As a group, at least one group is bonded to form a ring.

[0293] It is understandable that when n 25 Greater than or equal to 2, and two adjacent R 31 When bonding to form a ring, Ar6 can condense with the bonded ring. This allows for a larger planar group to form at Ar6 of the second host material HN, resulting in relatively high molecular rigidity for the second host material HN. This can lower the triplet energy level T1(HN) of the second host material HN and minimize the difference between the triplet energy level T1(HN) of the second host material HN and the triplet energy level T1(D) of the guest material D. This improves energy transfer efficiency and enhances the adequacy of energy transmission, thereby increasing the efficiency of the light-emitting device 100.

[0294] In some implementations, during the process of light emission by the light-emitting device 100 (for example, the first light-emitting device 101), the electrons in the light-emitting layer 131 are majority carriers, that is, the number of electrons in the light-emitting layer 131 is greater than the number of holes, so that the excess electrons are distributed on the second host material HN, resulting in a high electron distribution density on the second host material HN, which can easily lead to the degradation of the second host material HN, and have an adverse effect on the molecular stability of the second host material HN and the life of the light-emitting device 100.

[0295] In order to improve the stability of the second host material HN, in some embodiments, 10 When L is a single bond, at least one of Ar5, Ar6 and Ar7 is a deuterated group. 10 In the case of any one selected from substituted or unsubstituted C1-C30 alkylene, substituted or unsubstituted C6-C30 arylene and substituted or unsubstituted C6-C30 heteroarylene, Ar5, Ar6 and L10 wherein at least one is a deuterated group.

[0296] Understandably, in L 10 In the case of a single bond, in the structure of the second host material HN, the three parts directly connected to the triazine group are Ar5, Ar6 and Ar7. 10 In the case of any one selected from substituted or unsubstituted C1-C30 alkylene, substituted or unsubstituted C6-C30 arylene and substituted or unsubstituted C6-C30 heteroarylene (i.e., L 10 is not a single bond), the three parts directly connected to the triazine group are Ar5, Ar6 and L 10 Therefore, through the above arrangement, in the structure of the second host material HN, at least one of the three parts directly connected to the triazine group is a deuterated structure.

[0297] As described above, the structure of the deuterated group contains at least one deuterium atom. When at least one of the three moieties directly connected to the triazine group is a deuterated structure, at least one of the three moieties directly connected to the triazine group in the structure of the second host material HN contains deuterium. Since the atomic weight of deuterium is twice that of hydrogen, by providing at least one of the three moieties directly connected to the triazine group with deuterium, the molecular vibration at the location of the triazine group in the structure of the second host material HN can be effectively suppressed, thereby improving the molecular stability of the triazine group. In this way, the thermal stability of the second host material HN can be improved, thereby increasing the lifespan of the light-emitting device 100.

[0298] In some embodiments, in the structure represented by formula (V), the ratio of the number of hydrogen atoms and the sum of the number of hydrogen atoms and the number of deuterium atoms in the deuterated group is greater than or equal to 20%.

[0299] That is, when Ar5 is a deuterated group in the structure shown in general formula (V), the number of hydrogen atoms N in Ar5 is H-Ar5 , the number of deuterium in Ar5 N D-Ar5 , satisfying:

[0300] In the case where Ar6 is a deuterated group in the structure shown in general formula (V), the number of hydrogen atoms in Ar6 is N H-Ar6 , the number of deuterium in Ar6 N D-Ar6 , satisfying:

[0301] In the case where Ar7 is a deuterated group in the structure shown in general formula (V), the number of hydrogen atoms in Ar7 is N H-Ar7 , the number of deuterium in Ar7 N D-Ar7 , satisfying:

[0302] In the structure shown in general formula (V), L 10 In the case of a deuterated group, L 10 The number of hydrogen atoms N H-L10 , L 10 The number of deuterium N D-L10 , satisfying:

[0303] In some examples, in the structure shown in Formula (V), L 10 is a single bond, and Ar5, Ar6 and Ar7 are all deuterated groups. In this case, the number of hydrogen atoms in Ar5 is N H-Ar5 , the number of deuterium in Ar5 N D-Ar5 , the number of hydrogen atoms in Ar6 N H- Ar6 , the number of deuterium in Ar6 N D-Ar6 , the number of hydrogen atoms in Ar7 is N H-Ar7 , the number of deuterium in Ar7 N D-Ar7 , satisfying: and, and,

[0304] For Ar5, Ar6 and L 10 In the case where all three are deuterated groups, and in Ar5, Ar6 and Ar7, or Ar5, Ar6 and L 10 For the understanding of two of them being deuterated groups, please refer to the above content and will not be repeated here.

[0305] It should be noted that here Ar5, Ar6, Ar7 and L 10 For the understanding of the number of hydrogen and the number of deuterium in Ar3, please refer to the above description of the number of hydrogen and the number of deuterium in Ar3; no further details will be given here.

[0306] It can be understood that in the structure shown in general formula (V), when the ratio between the number of hydrogens in the deuterated group and the total number of hydrogens and deuteriums is greater than or equal to 20%, compared with the case where the ratio between the number of hydrogens in the deuterated group and the total number of hydrogens and deuteriums is less than 20%, the deuterium content in the three parts directly connected to the triazine group in the second host material HN is relatively high. In this way, the suppression effect of the molecular vibration at the position of the triazine group is relatively better, so that the molecular stability of the second host material HN is relatively higher, thereby improving the life of the light-emitting device 100.

[0307] In some examples, in the structure represented by formula (V), the ratio of the number of hydrogen atoms and the sum of the number of hydrogen atoms and the number of deuterium atoms in the deuterated group is greater than or equal to 40%.

[0308] For example, in the structure represented by general formula (V), the number of hydrogen atoms in the deuterated group and the ratio between the number of hydrogen atoms and the total number of deuterium atoms can be 20%, 30%, 45%, 70%, 80% or 100%, etc.

[0309] An exemplary structure of the second host material HN represented by the general formula (V) is described below.

[0310] In some examples, when the second host material HN includes a dibenzofuranyl group, the structural formula of the second host material HN may be as shown below.

[0311] In some examples, when the second host material HN includes a benzodibenzofuranyl group, the structural formula of the second host material HN may be as shown below.

[0312] In some examples, when the second host material HN includes a carbazole group, the structural formula of the second host material HN may be as shown below.

[0313] In some examples, when the second host material HN includes a benzocarbazolyl group, the structural formula of the second host material HN may be as shown below.

[0314] In some examples, when the second host material HN includes a dibenzothiophene group, the structural formula of the second host material HN may be as shown below.

[0315] In some examples, when the second host material HN includes a naphthyl group, the structural formula of the second host material HN may be as shown below.

[0316] It should be noted that the above-listed structural formulas are examples of the structure of the second host material HN and are not intended to limit the second host material HN. Furthermore, (HN2-x) in the above structural formulas is a synonym for each structural formula and is not part of the structural formula itself, where x is a positive integer.

[0317] In some embodiments, a mass ratio between the first host material HP and the second host material HN is greater than or equal to 2:8 and less than or equal to 8:2.

[0318] Illustratively, the first host material HP is selected from any one of the structures represented by general formula (IV); and the second host material HN is selected from any one of the structures represented by general formula (V).

[0319] It should be noted that the mass ratio between the first host material HP and the second host material HN is greater than or equal to 2:8 and less than or equal to 8:2, which means that the mass m of the first host material HP is greater than or equal to 2:8 and less than or equal to 8:2. HP , and the mass m of the second host material HN HN , satisfying:

[0320] It can be understood that when the mass ratio between the first main material HP and the second main material HN is greater than or equal to 2:8 and less than or equal to 8:2, the mass ratio between the first main material HP and the second main material HN is reasonable. The mass ratio between the first main material HP and the second main material HN can be flexibly selected according to the different hole transport properties of the hole transport functional layer 132 and the different electron transport properties of the electron transport functional layer 133. In this way, the electron transport rate and the hole transport rate in the light-emitting device 100 (for example, the first light-emitting device 101) can be relatively balanced, the exciton yield can be increased, the energy utilization rate can be relatively high, and the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101) can be improved.

[0321] In some examples, a mass ratio between the first host material HP′ and the second host material HN is greater than or equal to 3:7 and less than or equal to 7:3.

[0322] Exemplarily, the mass ratio between the first host material HP and the second host material HN is 2:8, 3:7, 4:6, 4:5, 1:1, 7:3 or 8:2, etc.

[0323] In some embodiments, the light emitting device is configured to emit light of a first wavelength, where the light of the first wavelength is red light; the chromaticity coordinate CIEx of the red light ranges from 0.678 to 0.684; and the chromaticity coordinate CIEy of the red light ranges from 0.316 to 0.323.

[0324] Illustratively, the chromaticity coordinate CIEx of the red light is 0.678, 0.680, 0.681, 0.682, 0.683, or 0.684.

[0325] Illustratively, the chromaticity coordinate CIEy of the red light is 0.316, 0.317, 0.319, 0.320, 0.321 or 0.323.

[0326] In order to objectively evaluate the technical effects of the embodiments of the present disclosure, the following experimental examples and comparative examples are used to describe the technical solutions provided by the present disclosure in detail. According to different evaluation indicators, the following experimental examples and comparative examples are divided into a first group of experimental examples and a second group of experimental examples.

[0327] The first group of test cases

[0328] The following examples and comparative examples use different materials to form the light-emitting layer 131 of the first light-emitting device 101, and compare the voltage, current efficiency, color of emitted light, and device life of the first light-emitting device 101. The color of the emitted light is represented by the chromaticity coordinates CIEx and CIEy in the CIE chromaticity diagram.

[0329] In the related art, the CIE chromaticity diagram is a color system created by the International Commission on Illumination (CIE), in which color attributes can be represented by chromaticity coordinates CIEx and CIEy.

[0330] In the following comparative examples and embodiments, the structure of the first light-emitting device 101 and the test conditions of the first light-emitting device 101 are the same.

[0331] 6 , a method for preparing a light-emitting substrate 200 including a first light-emitting device 101 is as follows: a substrate 210 (glass substrate) provided with an array layer 310, a pixel defining layer 221 and a first electrode 11 (the material of the first electrode 11 is indium tin oxide) is used as a backplane, and the backplane is placed in a vacuum evaporation device, and a hole injection layer 1321, a first hole transport layer 1322, a second hole transport layer 1323, a light-emitting layer 131, a hole blocking layer 1333, an electron transport layer 1332, an electron injection layer 1331, a second electrode 12, and a cathode covering layer 15 are sequentially formed on the backplane using the material of the hole injection layer 1321, the material of the first hole transport layer 1322, the material of the second hole transport layer 1323, the material of the light-emitting layer 131, the material of the hole blocking layer 1333, the material of the electron transport layer 1332, the material of the electron injection layer 1331, the material of the second electrode 12, and the material of the cathode covering layer 15. Before use, the backboard was ultrasonically treated in deionized water and then dried at 100°C.

[0332] It should be noted that the thickness and materials of the first electrode 11, hole injection layer 1321, first hole transport layer 1322, hole blocking layer 1333, electron transport layer 1332, electron injection layer 1331, second electrode 12, and cathode cover layer 15 in the embodiment and the comparative example are the same, and the thickness of the second hole transport layer 1323 and the light-emitting layer 131 are the same. The material of the second hole transport layer 1323 and the material of the light-emitting layer 131 are not exactly the same. Among them, among the materials of the light-emitting layer 131, the guest material D is the same, and the structure of the guest material D is shown in the following formula (RD), and the structures of the first host material HP and the first host material HN are different.

[0333] The materials of the light-emitting layer 131 in the following comparative example include a comparative first host material I and a comparative second host material I, and the materials of the second hole transport layer 1323 include a comparative hole transport functional material; wherein, the structure of the comparative first host material I is shown in the following formula (R-HP), the structure of the comparative second host material I is shown in the following formula (R-HN), and the structure of the comparative hole transport functional material is shown in the following formula (R-HT).

[0334] It should be noted that (R-HP), (R-HN) and (R-HT) in the above structural formulas are aliases for each structural formula and are not part of the structural formula structure.

[0335] The materials of the light-emitting layer 131 and the second hole transport layer 1323 of the first light-emitting device 101 of the embodiment and the comparative example are described below.

[0336] In Example 1, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP1-1); the structural formula of the second host material HN is shown in (HN1-1); and the structural formula of the material of the second hole-transporting layer 1323 is shown in (HT-1). Furthermore, the mass ratio of the first host material HP to the second host material HN is 4:6, and the mass ratio of the guest material D to the host material (comprising the first host material HP and the second host material HN) is 2%.

[0337] In Example 2, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP1-2); the structural formula of the second host material HN is shown in (HN1-3); and the structural formula of the material of the second hole-transporting layer 1323 is shown in (HT-2). Furthermore, the mass ratio of the first host material HP to the second host material HN is 4:6, and the mass ratio of the guest material D to the host material (comprising the first host material HP and the second host material HN) is 2%.

[0338] In Example 3, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP1-3); the structural formula of the second host material HN is shown in (HN1-2); and the structural formula of the material of the second hole-transporting layer 1323 is shown in (HT-3). Furthermore, the mass ratio of the first host material HP to the second host material HN is 4:6, and the mass ratio of the guest material D to the host material (comprising the first host material HP and the second host material HN) is 2%.

[0339] In Example 4, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP2-1); the structural formula of the second host material HN is shown in (HN-1); and the structural formula of the material of the second hole-transporting layer 1323 is shown in (HT-1). Furthermore, the mass ratio of the first host material HP to the second host material HN is 4:6, and the mass ratio of the guest material D to the host material (comprising the first host material HP and the second host material HN) is 2%.

[0340] In Example 5, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP2-5); the structural formula of the second host material HN is shown in (HN-1); and the structural formula of the material of the second hole-transporting layer 1323 is shown in (HT-1). Furthermore, the mass ratio of the first host material HP to the second host material HN is 4:6, and the mass ratio of the guest material D to the host material (comprising the first host material HP and the second host material HN) is 2%.

[0341] In Example 6, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP2-11); the structural formula of the second host material HN is shown in (HN-1); and the structural formula of the material of the second hole-transporting layer 1323 is shown in (HT-1). Furthermore, the mass ratio of the first host material HP to the second host material HN is 4:6, and the mass ratio of the guest material D to the host material (comprising the first host material HP and the second host material HN) is 2%.

[0342] In Comparative Example 1, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown as (R-HP); the structural formula of the second host material HN is shown as (R-HN); and the structural formula of the hole transport material is shown as (R-HT). Furthermore, the mass ratio of the first host material HP to the second host material HN is 4:6, and the mass ratio of the guest material D to the host material (comprising the first host material HP and the second host material HN) is 2%.

[0343] In order to more clearly describe the differences in the structural formulas of the first host material HP, the second host material HN, and the hole transport functional material HT used in the embodiment and the comparative example, the following Table 1 is used to more clearly show the structural formulas of the first host material HP, the second host material HN, and the hole transport functional material HT used in the embodiment and the comparative example.

[0344] Table 1

[0345] It should be noted that "Ax" in Table 1 refers to the corresponding structural formula Ax. For example, the sub-grid corresponding to the first host material HP in Example 1 is "HP1-1," which means that the structural formula of the first host material HP in the light-emitting layer 131 of Example 1 is shown as (HP1-1). The structural formulas represented by HP1-x, HP2-x, HN1-x, HT-x (x is a positive integer), R-HP, R-HN, and R-HT are described above and are not repeated here.

[0346] The absolute value of the highest occupied molecular orbital energy level (HOMO), the absolute value of the lowest occupied molecular orbital energy level (LUMO), the triplet energy level (T1), the hole mobility μ of the first host material HP, the second host material HN, the hole transport functional material HT, the comparative hole transport functional material R-HT, the comparative first host material IR-HP, and the comparative second host material IR-HN shown in Table 1 h , electron mobility μ e The peak wavelengths of the emission spectra of the exciplexes are shown in Table 2.

[0347] Table 2

[0348] It should be noted that the absolute value of the highest occupied molecular orbital energy level (HOMO), the absolute value of the lowest occupied molecular orbital energy level (LUMO), and the triplet energy level (T1) in Table 2 are all in electron volts, symbolized by eV. "Mobility @ 5000" refers to the electron mobility μ under a preset electric field strength of 5000 V / m. e or hole mobility μ h "Peak wavelength" refers to the peak wavelength of the emission spectrum of the exciplex. The structural formulas represented by HP1-x, HP2-x, HN1-x, HT-x (x is a positive integer), R-HP, R-HN, and R-HT are as described above and will not be repeated here.

[0349] Based on the above materials, the first light-emitting device 101 of Examples 1 to 6 and Comparative Example 1 was tested for voltage (V), current efficiency (cd / A), emitted light color, and device lifespan. The voltage (V), current efficiency (cd / A), and device lifespan data were compared with those of Example 1. The test results are shown in Table 3 below. Device lifespan is characterized by the parameter LT95, while the emitted light color is represented by the chromaticity coordinates CIEx and CIEy in the CIE chromaticity diagram.

[0350] Table 3

[0351] As can be seen from Table 3, in Examples 1 to 6 and Comparative Example 1, the chromaticity coordinates CIEx of the color of the light emitted by the light-emitting layer 131 of the first light-emitting device 101 are all in the range of 0.680 to 0.682, and the chromaticity coordinates CIEy are all in the range of 0.318 to 0.321, indicating that the color of the light emitted by the light-emitting layer 131 of the first light-emitting device 101 in Examples 1 to 6 and Comparative Example 1 is red, which is the same as the preset color.

[0352] As shown in Table 3, the current efficiencies of Examples 1 to 6 are relatively high compared to Comparative Example 1. This is because the highest occupied molecular orbital (HOMO) energy level (R-HT) of the comparative hole transport material R-HT in Comparative Example 1 is higher than the highest occupied molecular orbital (HOMO) energy level (HT) of the hole transport material HT in Examples 1 to 6. This results in the energy of the excitons generated by the exciplex (R-HT) / (R-HN) formed by the comparative hole transport material R-HT and the comparative second host material IR-HN being higher than the energy of the excitons generated by the exciplex (R-HP) / (R-HN) formed by the comparative first host material IR-HP and the comparative second host material IR-HN. This results in the peak wavelength of the exciplex (R-HT) / (R-HN) formed by the comparative hole transport material R-HT and the comparative second host material IR-HN being blue-shifted to 492 nm. As a result, the difference between the peak wavelength of the exciplex (R-HT) / (R-HN) formed by the comparative hole transport material R-HT and the comparative second host material IR-HN and the peak wavelength of the exciplex (R-HP) / (R-HN) formed by the comparative first host material IR-HP and the comparative second host material IR-HN increases to 30 nm, which is relatively high. Consequently, the correspondence between the peak wavelength of the exciplex (R-HT) / (R-HN) formed by the comparative hole transport material R-HT and the comparative second host material IR-HN and the peak wavelength WLP(D) of the absorption spectrum of the guest material D is relatively low, resulting in relatively low energy utilization and reduced efficiency of the first light-emitting device 101.

[0353] As shown in Table 3, compared with Comparative Example 1, Examples 1 to 6 have relatively long device lifespans. This is because in the light-emitting layer 131 of the first light-emitting device 101 of Examples 1 to 6, the first host material HP, the second host material HN, and the hole transport material HT are all deuterated materials, while in Comparative Example 1, the first host material IR-HP, the second host material IR-HN, and the hole transport material R-HT are all materials that do not contain deuterium atoms. Because deuterium has an atomic weight twice that of hydrogen, it can effectively suppress molecular vibrations, thereby improving the molecular stability of the first host material HP, the second host material HN, and the hole transport material HT. This improves the thermal stability of the first host material HP, the second host material HN, and the hole transport material HT, thereby increasing the device lifespan of the first light-emitting device 101. Compared with Examples 1 to 3, the device lifespan of Examples 4 to 6 is relatively longer. This is because in Examples 4 to 6, the first host material HP contains relatively more deuterium atoms, which can make the device lifespan of the first light-emitting device 101 relatively longer.

[0354] It can be seen from the above embodiments and comparative examples that the absolute value of the difference between the peak wavelength WLP (HP / HN) of the emission spectrum of the exciplex HP / HN formed by the first host material HP and the second host material HN, and the peak wavelength WLP (HP / HN) of the emission spectrum of the exciplex HT / HN formed by the hole transport functional material HT and the second host material HN, is less than or equal to 10 nm. In this way, during the light-emitting process of the light-emitting device 100, the guest material D can not only receive the energy transmitted by the exciplex HP / HN formed by the first host material HP and the second host material HN, but also receive the energy transmitted by the exciplex HT / HN formed by the hole transport functional material HT and the second host material HN. The energy transmission efficiency can be effectively improved, the energy utilization rate can be improved, and the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101) can be effectively improved. At the same time, the present disclosure improves the thermal stability of the first host material HP, the second host material HN, and / or the hole transport functional material HT by setting the first host material HP, the second host material HN, and / or the hole transport functional material HT as deuterated materials, thereby increasing the device life of the light-emitting device 100 (for example, the first light-emitting device 101).

[0355] The second group of test cases

[0356] The following examples and comparative examples use different materials to make the light-emitting layer 131 of the first light-emitting device 101, and compare the voltage, current efficiency, color of the emitted light, device life, and efficiency decay index ΔE of the first light-emitting device 101. The color of the emitted light is represented by the chromaticity coordinates CIEx and CIEy in the CIE chromaticity diagram. When calculating the efficiency decay index ΔE, the first preset current density I1 refers to a current density of 1 mA / cm 2 The second preset current density I2 refers to a current density of 15mA / cm 2 .

[0357] In the related art, the CIE chromaticity diagram is a color system created by the International Commission on Illumination (CIE), in which color attributes can be represented by chromaticity coordinates CIEx and CIEy.

[0358] In the following comparative examples and embodiments, the structure of the first light-emitting device 101 and the test conditions of the first light-emitting device 101 are the same.

[0359] For example, as shown in FIG6 , the preparation method of the light-emitting substrate 200 including the first light-emitting device 101 is as follows: a substrate 210 provided with an array layer 310, a pixel defining layer 221, and a first electrode 11 (the material of the first electrode 11 is indium tin oxide) is used as a backplane, and the backplane is placed in a vacuum evaporation device, and the hole injection layer 1321, the first hole transport layer 1322, the second hole transport layer 1323, the light-emitting layer 131, the hole blocking layer 1333, the electron transport layer 1332, the electron injection layer 1331, and the second electrode 12 are sequentially formed on the backplane. The backplane is cleaned and dried before use.

[0360] It should be noted that the thickness and materials of the first electrode 11, hole injection layer 1321, first hole transport layer 1322, second hole transport layer 1323, hole blocking layer 1333, electron transport layer 1332, electron injection layer 1331, and second electrode 12 in the embodiment and the comparative example are the same, and the thickness of the light-emitting layer 131 is the same. Among them, the materials of the hole injection layer 1321, first hole transport layer 1322, second hole transport layer 1323, hole blocking layer 1333, electron transport layer 1332, electron injection layer 1331, and second electrode 12 are HAT-CN, NPB, TCTA, BCP, TPBi, LiF, and aluminum, respectively; the structures of HAT-CN, NPB, TCTA, BCP, and TPBi are as shown below. The thicknesses of the hole injection layer 1321, the first hole transport layer 1322, the second hole transport layer 1323, the hole blocking layer 1333, the electron transport layer 1332, the electron injection layer 1331, and the second electrode 12 are 5 nm, 100 nm, 60 nm, 5 nm, 30 nm, 1 nm, and 150 nm, respectively. The materials of the light-emitting layer 131 are not identical. The guest material D of the light-emitting layer 131 is the same, and guest material D is Ir(piq)3, with the structure shown below. The structures of the first host material HP and the first host material HN are different.

[0361] It should be noted that (HAT-CN), (NPB), (TCTA), (BCP), (TPBi), and (Ir(piq)3) in the above structural formulas are aliases for each structural formula and are not part of the structural formula structure.

[0362] The materials of the light-emitting layer 131 in the following comparative examples include a comparative first host material II, a comparative first host material III, and a comparative second host material II; wherein, the structure of the comparative first host material II is shown in the following formula (R-HP2-1), the structure of the comparative first host material III is shown in the following formula (R-HP2-2), and the structure of the comparative second host material II is shown in the following formula (R-HN2).

[0363] It should be noted that (R-HP2-1), (R-HP2-2), and (R-HN2) in the above structural formulas are aliases for each structural formula and are not part of the structural formula structure.

[0364] The materials of the light emitting layer 131 of the first light emitting device 101 of the embodiment and the comparative example are described below.

[0365] In Example 7, the light-emitting layer 131 includes a first host material HP, a second comparative host material II, and a guest material D. The first host material HP has a structural formula shown as (HP2-7), and the second comparative host material II has a structural formula shown as (R-HN2). Furthermore, the mass ratio of the first host material HP to the second comparative host material II to the guest material D is 49:49:2.

[0366] In Example 8, the light-emitting layer 131 includes a first host material II, a second host material HN, and a guest material D. The structural formula of the first host material II is shown as (R-HP2-1), and the structural formula of the second host material HN is shown as (HN2-1). Furthermore, the mass ratio of the first host material II, the second host material HN, and the guest material D is 49:49:2.

[0367] In Example 9, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP2-7), and the structural formula of the second host material HN is shown in (HN2-1). Furthermore, the mass ratio of the first host material HP to the second host material HN to the guest material D is 49:49:2.

[0368] In Example 10, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP2-22), and the structural formula of the second host material HN is shown in (HN2-18). Furthermore, the mass ratio of the first host material HP to the second host material HN to the guest material D is 49:49:2.

[0369] In Example 11, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP2-18), and the structural formula of the second host material HN is shown in (HN2-16). Furthermore, the mass ratio of the first host material HP to the second host material HN to the guest material D is 49:49:2.

[0370] In Example 12, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP2-11), and the structural formula of the second host material HN is shown in (HN2-19). Furthermore, the mass ratio of the first host material HP to the second host material HN to the guest material D is 49:49:2.

[0371] In Example 13, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP2-7), and the structural formula of the second host material HN is shown in (HN2-1). Furthermore, the mass ratio of the first host material HP to the second host material HN to the guest material D is 59:39:2.

[0372] In Example 14, the light-emitting layer 131 includes a first host material HP, a second host material HN, and a guest material D. The structural formula of the first host material HP is shown in (HP2-7), and the structural formula of the second host material HN is shown in (HN2-1). Furthermore, the mass ratio of the first host material HP to the second host material HN to the guest material D is 39:59:2.

[0373] In Comparative Example 2, light-emitting layer 131 includes a comparative first host material II, a comparative second host material II, and a guest material D. The structural formula of the comparative first host material II is shown as (R-HP2-1); the structural formula of the comparative second host material II is shown as (R-HN2). Furthermore, the mass ratio of the comparative first host material II, the comparative second host material II, and the guest material D is 49:49:2.

[0374] In Comparative Example 3, light-emitting layer 131 includes a comparative first host material III, a comparative second host material II, and a guest material D. The structural formula of the comparative first host material III is shown as (R-HP2-2); the structural formula of the comparative second host material II is shown as (R-HN2). Furthermore, the mass ratio of the comparative first host material III to the comparative second host material II to the guest material D is 49:49:2.

[0375] In order to more clearly describe the structural formulas of the first host material HP and the second host material HN used in the embodiments and comparative examples, as well as the differences in the mass ratios between the first host material HP, the second host material HN and the guest material D, the following Table 4 is used to more clearly show the structural formulas of the first host material HP and the second host material HN used in the embodiments and comparative examples, as well as the mass ratios between the first host material HP, the second host material HN and the guest material D.

[0376] Table 4

[0377] It should be noted that "Ax" in Table 4 refers to the corresponding structural formula Ax. For example, the subcell corresponding to the first host material HP in Example 4 is "HP2-7," which means that the structural formula of the first host material HP in the light-emitting layer 131 of Example 1 is shown as (HP2-7). The structural formulas represented by HP2-x, HN2-x (x is a positive integer), R-HP2-1, R-HP2-2, and R-HN2 are as described above and are not repeated here.

[0378] The HOMO electron cloud distributions of the first host materials HP2-7, HP2-11, HP2-18, and HP2-22 are shown in Figures 14 through 17. The LUMO electron cloud distributions of the second host materials HN2-1, HN2-16, HN2-18, and HN2-19 are shown in Figures 18 through 21. The above HOMO and LUMO electron cloud distributions were calculated using Gaussian calculation software using the density functional B3LYP / 6-31G(d) method and optimizing the ground-state structure of the molecules.

[0379] Based on the above materials, the first light-emitting devices 101 of Examples 7 to 14 and Comparative Examples 2 and 3 were tested for voltage (V), current efficiency (cd / A), emitted light color, device lifespan, and efficiency decay index ΔE. The voltage (V), current efficiency (cd / A), and device lifespan data were compared with Comparative Example 2. The test results are shown in Table 5 below. Device lifespan is characterized by the parameter LT95, and emitted light color is represented by the chromaticity coordinates CIEx and CIEy in the CIE chromaticity diagram.

[0380] Table 5

[0381] As can be seen from Table 5, in Examples 7 to 14 and Comparative Examples 2 to 3, the chromaticity coordinate CIEx of the color of the light emitted by the light-emitting layer 131 of the first light-emitting device 101 is 0.68, and the chromaticity coordinate CIEy is 0.32, indicating that the color of the light emitted by the light-emitting layer 131 of the first light-emitting device 101 in Examples 7 to 14 and Comparative Examples 2 to 3 is red, which is the same as the preset color.

[0382] As shown in Table 3, compared with Comparative Examples 2 to 3, Examples 7 to 14 exhibit relatively long device lifespans. This is because the first host material HP and the second host material HN in the light-emitting layer 131 of the first light-emitting device 101 of Examples 7 to 14 are both deuterated materials, while in Comparative Examples 2 to 3, the first host material IIR-HP2-1, the first host material IIIR-HP2-2, and the second host material IIR-HN2 are all materials that do not contain deuterium atoms. Because deuterium has an atomic weight twice that of hydrogen, it effectively suppresses molecular vibrations, enhancing the molecular stability of the first host material HP and the second host material HN. This improves the thermal stability of the first host material HP and the second host material HN, thereby increasing the device lifespan of the first light-emitting device 101.

[0383] As shown in Table 5, compared with Comparative Example 3, Examples 7 to 14 have relatively low efficiency decay exponents ΔE. This is because in Examples 7 to 14, the structure of the first host material HP includes a triarylamine structure, which allows the HOMO electron cloud of the first host material HP to have a higher distribution density on the triarylamine structure. This improves the hole mobility of the first host material HP, shifts the exciton recombination region of the light-emitting layer 131 of the first light-emitting device 101 toward the center of the light-emitting layer 131, and reduces the probability of triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ). This reduces exciton quenching and mitigates the efficiency roll-off problem at high current density. Among them, compared with Examples 7 to 12 and 14, the efficiency decay index ΔE of Example 13 is relatively low. This is because the mass percentage of the first host material HP in the material of the light-emitting layer 131 in Example 13 is relatively high, which can make the exciton recombination region of the light-emitting layer 131 of the first light-emitting device 101 relatively closer to the middle position of the light-emitting layer 131, making the probability of triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ) relatively lower.

[0384] Referring to Table 5, Examples 7 through 14 all have high current efficiencies. This is because the structure of the first host material HP includes a triarylamine structure, and the structure of the second host material HN includes a triazine group, resulting in high hole and electron transport properties, which can increase the exciton yield and improve the efficiency of the first light-emitting device 101. Specifically, the mass percentage of the first host material HP in the material of the light-emitting layer 131 in Example 13 is 59%, and the mass percentage of the first host material HP in the material of the light-emitting layer 131 in Example 14 is 39%. This indicates that within a certain range of the mass percentage of the first host material HP in the material of the light-emitting layer 131, the efficiency of the first light-emitting device 101 can be relatively high.

[0385] As can be seen from the above embodiments and comparative examples, the present disclosure, by selecting the first host material HP from any of the structures represented by general formula (IV), can improve the efficiency of the light-emitting device 100 (e.g., the first light-emitting device 101) and alleviate the problem of efficiency roll-off at high current densities. Furthermore, by configuring the first host material HP and the second host material HN to be deuterated materials, the present disclosure can improve the thermal stability of the first host material HP and the second host material HN, thereby increasing the device lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0386] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in the present disclosure should be included within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A light emitting device, comprising: A first electrode and a second electrode are stacked; at least one light emitting unit disposed between the first electrode and the second electrode; Wherein, the light-emitting unit comprises a light-emitting layer, and the material of the light-emitting layer comprises: a first host material, a second host material and a guest material; The difference between the triplet energy level of the first host material and the triplet energy level of the guest material is greater than or equal to 0 and less than or equal to 0.4 eV; the difference between the triplet energy level of the second host material and the triplet energy level of the guest material is greater than or equal to 0 and less than or equal to 0.4 eV.

2. The light emitting device according to claim 1, wherein: The light emitting unit further comprises: A hole transport functional layer, located on a side of the light-emitting layer close to the first electrode and in contact with the light-emitting layer; the material of the hole transport functional layer includes a hole transport functional material; The exciplex of the light-emitting unit includes a first exciplex and a second exciplex; the first exciplex is an exciplex formed by the first host material and the second host material; the second exciplex is an exciplex formed by the hole transport functional material and the second host material.

3. The light emitting device according to claim 2, wherein: The junction between the hole transport functional layer and the light emitting layer contains the first exciplex and the second exciplex.

4. The light emitting device according to claim 2 or 3, wherein: An absolute value of a difference between a peak wavelength of an emission spectrum of the first exciplex and a peak wavelength of an emission spectrum of the second exciplex is less than or equal to 10 nm.

5. The light emitting device according to any one of claims 1 to 4, wherein: The first host material is selected from any one of the structures shown in general formula (I); wherein R1 and R2 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted diphenylfluorenyl and substituted or unsubstituted spirofluorenyl; L1 and L2 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene and substituted or unsubstituted naphthylene; n1 and n2 are the same or different and are independently selected from any one of 0 and 1; n3 and n6 are the same or different and are independently selected from any one of 0, 1, 2, 3 and 4; n4 and n5 are the same or different and are independently selected from any one of 0, 1 and 2.

6. The light emitting device according to any one of claims 1 to 5, wherein: The second main material is selected from any one of the structures shown in general formula (II); wherein L3, L4 and L5 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene, substituted or unsubstituted benzodibenzofuranylene, substituted or unsubstituted dibenzothienylene, substituted or unsubstituted benzodibenzothienylene, substituted or unsubstituted carbazolylene, substituted or unsubstituted benzocarbazolylene and substituted or unsubstituted phenanthroxazolyl; R3, R4 and R5 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted benzodibenzofuranyl, substituted or unsubstituted dibenzothienyl, substituted or unsubstituted benzodibenzothienyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted benzocarbazolyl and substituted or unsubstituted phenanthroxazolyl; n7, n8 and n9 are the same or different and are independently selected from any one of 0 and 1.

7. The light emitting device according to any one of claims 2 to 6, wherein: The hole transport functional material is selected from any one of the structures shown in general formula (III); wherein L6, L7 and L8 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene and substituted or unsubstituted dibenzothiophenylene; R6, R7 and R8 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothienyl, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted diphenylfluorenyl, substituted or unsubstituted spirofluorenyl and substituted or unsubstituted adamantyl; n 10 、n 11 and n 12 are the same or different, and are independently selected from any one of 0 and 1.

8. The light emitting device according to any one of claims 2 to 7, wherein: At least one of the first host material, the second host material and the hole transport functional material is a deuterated material.

9. The light emitting device according to any one of claims 2 to 8, wherein: The mass ratio between the first main material and the second main material is greater than or equal to 3:7 and less than or equal to 1:

1.

10. The light emitting device according to claim 1, wherein: The first host material is selected from any one of the structures shown in general formula (IV); Wherein, L9 is selected from any one of a single bond, a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group; Ar1 and Ar2 are fused; Ar1 ​​and Ar2 share two carbon atoms, which are X a and X b , and, X a and X b Any two adjacent ones among X1, X2, X3, X4 and X5; Among X1, X2, X3, X4 and X5, except X a and X b The remaining three are independently selected from N and C (R a ) R a Any one selected from hydrogen and deuterium; Ar1 is selected from any one of Ar1-a to Ar1-i; Y is selected from O, S, Se, C=O, S(=O)2, C(R b R c )、Si(R d R e )、N(R f )、P(R g )、P(=O)(R h ) and B(R i ) R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 , R b , R c , R d , R e , R f , R g , R h and R i are the same or different and are independently selected from any one of hydrogen, tritium, halogen, nitrile, nitro, hydroxyl, carbonyl, ester, imide, amide, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted alkylthio, substituted or unsubstituted arylthio, substituted or unsubstituted alkylsulfonyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted alkenyl, substituted or unsubstituted silyl, substituted or unsubstituted boron, substituted or unsubstituted amine, substituted or unsubstituted arylphosphino, substituted or unsubstituted phosphine oxide, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and substituted or unsubstituted heterocyclic group, or may be connected with adjacent substituents to form a substituted or unsubstituted ring; n 13 、n 16 、n 18 、n 20 and n 22 The same or different, each independently selected from any one of 0, 1 and 2; n 14 、n 15 、n 17 、n 19 、n 21 and n 23 The same or different, each independently selected from any one of 0, 1, 2, 3 and 4.

11. The light emitting device according to claim 10, wherein: The general formula (IV) satisfies at least one of the following conditions (a) to (m): (a) R9, R 10 , R 11 , R 12 and R 13 In the example, every two adjacent pairs form a group, and at least one group is bonded to form a ring; (b)R 14 , R 15 , R 16 , R 17 and R 18 In the example, every two adjacent pairs form a group, and at least one group is bonded to form a ring; (c) in n 13 When the two R 19 Bonding to form a ring; (d) in n 14 When it is greater than or equal to 2, every two adjacent R 20 As a group, at least one group is bonded to form a ring; (e) in n 15 When it is greater than or equal to 2, every two adjacent R 21 As a group, at least one group is bonded to form a ring; (f) in n 16 When the two R 22 Bonding to form a ring; (g) in n 17 When it is greater than or equal to 2, every two adjacent R 23 As a group, at least one group is bonded to form a ring; (h) in n 18 When the two R 24 Bonding to form a ring; (i) in n 19 When it is greater than or equal to 2, every two adjacent R 25 As a group, at least one group is bonded to form a ring; (j) in n 20 When the two R 26 Bonding to form a ring; (k) in n 21 When it is greater than or equal to 2, every two adjacent R 27 As a group, at least one group is bonded to form a ring; (l) in n 22 When the two R 28 Bonding to form a ring; (m) in n 23 When it is greater than or equal to 2, every two adjacent R 29 As a group, at least one group is bonded to form a ring.

12. The light emitting device according to claim 10 or 11, wherein: R9, R 10 , R 11 , R 12 and R 13 Among them, at least one is deuterium; R 14 , R 15 , R 16 , R 17 and R 18 Among them, at least one is deuterium; When L9 is a single bond, at least one of X1, X2, X3, X4 and X5 is a deuterated carbon; When L9 is selected from any one of a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group, L9 is a deuterated group.

13. The light emitting device according to any one of claims 10 to 12, wherein: In the case where L9 is a single bond, the ratio between the number of deuterium and the sum of the number of hydrogen and the number of deuterium in Ar3, Ar4 and Ar2 is greater than or equal to 50%; When L9 is selected from any one of substituted or unsubstituted C1-C30 alkylene, substituted or unsubstituted C6-C30 arylene and substituted or unsubstituted C6-C30 heteroarylene, the ratio of the number of deuterium and the total number of hydrogen to the number of deuterium in Ar3, Ar4 and L9 is greater than or equal to 50%.

14. The light emitting device according to any one of claims 1, 10 to 13, wherein: The second main material is selected from any one of the structures shown in general formula (V); Among them, L 10 Any one selected from a single bond, a substituted or unsubstituted C1-C30 alkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C6-C30 heteroarylene group; X6, X7, X8, X9 and X 10 are the same or different, independently selected from N and C(R j ) R j Any one selected from hydrogen, deuterium, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl, or may be connected with an adjacent substituent to form a substituted or unsubstituted ring; R 30 and R 31 are the same or different and are independently selected from any one of hydrogen, tritium, halogen, nitrile, nitro, hydroxyl, carbonyl, ester, imide, amide, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted alkylthio, substituted or unsubstituted arylthio, substituted or unsubstituted alkylsulfonyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted alkenyl, substituted or unsubstituted silyl, substituted or unsubstituted boron, substituted or unsubstituted amine, substituted or unsubstituted arylphosphino, substituted or unsubstituted phosphine oxide, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and substituted or unsubstituted heterocyclic group, or may be connected with adjacent substituents to form a substituted or unsubstituted ring; n 24 and n 25 The same or different, each independently selected from any one of 0, 1, 2, 3, 4 and 5.

15. The light emitting device according to claim 14, wherein: The general formula (V) satisfies at least one of the following conditions (n) to (p): (n) When X6, X7, X8, X9 and X 10 In the example, every two adjacent pairs form a group, and at least two pairs in a group are C(R j ) In the case of two R j Bonding to form a ring; (o) in n 24 When it is greater than or equal to 2, every two adjacent R 30 As a group, at least one group is bonded to form a ring; (p) in n 25 When it is greater than or equal to 2, every two adjacent R 31 As a group, at least one group is bonded to form a ring.

16. The light emitting device according to claim 14 or 15, wherein: In L 10 In the case of a single bond, at least one of Ar5, Ar6 and Ar7 is a deuterated group; In L 10 In the case of any one selected from substituted or unsubstituted C1-C30 alkylene, substituted or unsubstituted C6-C30 arylene and substituted or unsubstituted C6-C30 heteroarylene, Ar5, Ar6 and L 10 Among them, at least one is a deuterated group.

17. The light emitting device according to claim 16, wherein: In the deuterated group, the ratio of the number of hydrogen atoms to the sum of the number of hydrogen atoms and the number of deuterium atoms is greater than or equal to 20%.

18. The light emitting device according to any one of claims 10 to 17, wherein: The mass ratio between the first main material and the second main material is greater than or equal to 2:8 and less than or equal to 8:

2.

19. The light emitting device according to any one of claims 1 to 18, wherein: The light emitting device is configured to emit light of a first wavelength, wherein the light of the first wavelength is red light; the chromaticity coordinate CIEx of the red light has a value range of 0.678 to 0.684; and the chromaticity coordinate CIEy of the red light has a value range of 0.316 to 0.

323.

20. A light emitting device, comprising: A first electrode and a second electrode are stacked; at least one light emitting unit disposed between the first electrode and the second electrode; The light-emitting unit includes a light-emitting layer and a hole transport functional layer, wherein the hole transport functional layer is located on a side of the light-emitting layer close to the first electrode and in contact with the light-emitting layer; the material of the light-emitting layer includes: a first host material, a second host material and a guest material; the material of the hole transport functional layer includes a hole transport functional material; The exciplex of the light-emitting unit includes a first exciplex and a second exciplex; the first exciplex is an exciplex formed by the first host material and the second host material; the second exciplex is an exciplex formed by the hole transport functional material and the second host material.

21. The light emitting device according to claim 20, wherein: The junction between the hole transport functional layer and the light emitting layer contains the first exciplex and the second exciplex.

22. The light emitting device according to claim 20 or 21, wherein: An absolute value of a difference between a wavelength value corresponding to a peak of an emission spectrum of the first exciplex and a wavelength value corresponding to a peak of an emission spectrum of the second exciplex is less than or equal to 10 nm.

23. The light emitting device according to any one of claims 20 to 22, wherein: Under a preset electric field strength, a ratio of the electron mobility of the second host material to the hole mobility of the first host material is greater than or equal to 10 and less than or equal to 1000.

24. The light emitting device according to any one of claims 20 to 23, wherein: The difference between the triplet energy level of the first host material and the triplet energy level of the guest material is greater than or equal to 0 and less than or equal to 0.4 eV; the difference between the triplet energy level of the second host material and the triplet energy level of the guest material is greater than or equal to 0 and less than or equal to 0.4 eV.

25. The light emitting device according to any one of claims 20 to 24, wherein: The absolute value of the difference between the highest occupied molecular orbital energy level of the first host material and the highest occupied molecular orbital energy level of the guest material is less than or equal to 0.4 eV; the absolute value of the difference between the lowest unoccupied molecular orbital energy level of the second host material and the lowest unoccupied molecular orbital energy level of the guest material is less than or equal to 0.4 eV.

26. The light emitting device according to any one of claims 20 to 25, wherein: The first host material is selected from any one of the structures shown in general formula (I); wherein R1 and R2 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted diphenylfluorenyl and substituted or unsubstituted spirofluorenyl; L1 and L2 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene and substituted or unsubstituted naphthylene; n1 and n2 are the same or different and are independently selected from any one of 0 and 1; n3 and n6 are the same or different and are independently selected from any one of 0, 1, 2, 3 and 4; n4 and n5 are the same or different and are independently selected from any one of 0, 1 and 2.

27. The light emitting device according to any one of claims 20 to 26, wherein: The second main material is selected from any one of the structures shown in general formula (II); wherein L3, L4 and L5 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene, substituted or unsubstituted benzodibenzofuranylene, substituted or unsubstituted dibenzothienylene, substituted or unsubstituted benzodibenzothienylene, substituted or unsubstituted carbazolylene, substituted or unsubstituted benzocarbazolylene and substituted or unsubstituted phenanthroxazolyl; R3, R4 and R5 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted benzodibenzofuranyl, substituted or unsubstituted dibenzothienyl, substituted or unsubstituted benzodibenzothienyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted benzocarbazolyl and substituted or unsubstituted phenanthroxazolyl; n7, n8 and n9 are the same or different and are independently selected from any one of 0 and 1.

28. The light emitting device according to any one of claims 20 to 27, wherein: The hole transport functional material is selected from any one of the structures shown in general formula (III); wherein L6, L7 and L8 are the same or different and are independently selected from any one of substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted dibenzofuranylene and substituted or unsubstituted dibenzothiophenylene; R6, R7 and R8 are the same or different and are independently selected from any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothienyl, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted diphenylfluorenyl, substituted or unsubstituted spirofluorenyl and substituted or unsubstituted adamantyl; n 10 、n 11 and n 12 are the same or different, and are independently selected from any one of 0 and 1.

29. The light emitting device according to any one of claims 20 to 28, wherein: At least one of the first host material, the second host material and the hole transport functional material is a deuterated material.

30. The light emitting device according to any one of claims 20 to 29, wherein: The mass ratio between the first main material and the second main material is greater than or equal to 3:7 and less than or equal to 1:

1.

31. The light emitting device according to any one of claims 20 to 30, wherein: The light emitting device is configured to emit light of a first wavelength, wherein the light of the first wavelength is red light; the chromaticity coordinate CIEx of the red light has a value range of 0.678 to 0.684; and the chromaticity coordinate CIEy of the red light has a value range of 0.316 to 0.

323.

32. A display panel, wherein: comprising a plurality of light emitting devices according to any one of claims 1 to 31; It also includes: a plurality of pixel driving circuits, each of which is electrically connected to one of the light-emitting devices and is used to drive the light-emitting device to emit light.

33. A display device, wherein: comprising the display panel as claimed in claim 32; It also includes: a driving chip, and the driving chip is used to drive the display panel to display.

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