Light-emitting device, display panel and display device

Abstract

The embodiment of the invention provides a light-emitting device, a display panel and a display device, relates to the technical field of display and is used for improving the light-emitting efficiency of the light-emitting device and prolonging the service life of the light-emitting device. The light-emitting device comprises a first electrode, a second electrode and at least one light-emitting unit, wherein the first electrode and the second electrode are arranged in a stacked mode, and the light-emitting unit is arranged between the first electrode and the second electrode. Wherein the light-emitting unit comprises a light-emitting layer, and materials of the light-emitting layer comprise 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 less than or equal to 0.4 eV. 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 less than or equal to 0.4 eV. The light-emitting substrate is used for displaying images.

Description

Technical Field

[0001] 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

[0002] 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. Summary of the invention

[0003] The purpose of the embodiments of the present disclosure is to provide a light-emitting device, a display panel and a display apparatus, which are used to improve the light-emitting efficiency and device life of the light-emitting device.

[0004] To achieve the above objectives, the embodiments of the present disclosure provide the following technical solutions:

[0005] In one aspect, a light-emitting device is provided, comprising a first electrode and a second electrode stacked in layers, 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 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.

[0006] When the light-emitting device emits light, the first host material and the second host material can form an exciplex, and the triplet energy level of the exciplex is lower than the triplet energy level of the first host material and lower than the triplet energy level of the second host material. Therefore, through the above arrangement, on the one hand, the triplet energy level of the first host material and the triplet energy level of the second host material can be higher than the triplet energy level of the guest material, so that the triplet energy level of the exciplex can be higher than the triplet energy level of the guest material, realizing energy transfer from the exciplex to the guest material, preventing exciton quenching caused by exciton backflow during energy transfer, and improving the efficiency of the light-emitting device. On the other hand, the difference between the triplet energy level of the exciplex and the triplet energy level of the guest material can be relatively small, improving the energy transfer efficiency, improving the sufficiency of energy transfer, and improving the efficiency of the light-emitting device.

[0007] In some embodiments, the light-emitting unit further includes a hole transport functional layer, which 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 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.

[0008] In some embodiments, the interface between the hole transport functional layer and the light emitting layer includes a first exciplex and a second exciplex.

[0009] 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.

[0010] In some embodiments, the first host material is selected from any one of the structures shown in formula (I).

[0011]

[0012] 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.

[0013] In some embodiments, the second host material is selected from any one of the structures represented by formula (II).

[0014]

[0015] 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.

[0016] In some embodiments, the hole transport functional material is selected from any one of the structures shown in formula (III).

[0017]

[0018] 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 dibenzothienylene. 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 dibenzothienylene, 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.

[0019] 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.

[0020] In some embodiments, a mass 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.

[0021] In some embodiments, the first host material is selected from any one of the structures shown in formula (IV);

[0022]

[0023] 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.

[0024]

[0025] 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

[0026] B(R i ) 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 , Rg , R h and R i 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 phosphine oxide, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and substituted or unsubstituted heterocyclic groups, or may be connected with 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.

[0027] 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 two R 19 (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) 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 Bond to form a ring. (g) in n 17When 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 (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 Bond 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 Bond 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.

[0028] 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. In the case where 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, L9 is a deuterated group.

[0029] In some embodiments, when L9 is a single bond, the ratio of the number of deuteriums to the total number of hydrogens to the total number of deuteriums 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 deuteriums to the total number of hydrogens to the total number of deuteriums in Ar3, Ar4 and L9 is greater than or equal to 50%.

[0030] In some embodiments, the second host material is selected from any one of the structures shown in formula (V).

[0031]

[0032] Among them, L10 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 are the same or different, independently selected from N and C(R j ) in any one of 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 connected with an adjacent substituent to form a substituted or unsubstituted ring. 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. 24 and n 25 The 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.

[0033] 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 Bond 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.

[0034] (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.

[0035] In some embodiments, in L 10 When L is a single bond, at least one of Ar5, Ar6 and Ar7 is a deuterated group. 10In 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.

[0036] In some embodiments, in the deuterated group, the ratio between the number of hydrogen atoms and the sum of the number of hydrogen atoms and the number of deuterium atoms is greater than or equal to 20%.

[0037] 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.

[0038] 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.

[0039] On the other hand, 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 functional layer, and 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 comprises: a first host material, a second host material and a guest material. The material of the hole transport functional layer comprises a hole transport functional 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; the second exciplex is an exciplex formed by the hole transport functional material and the second host material.

[0040] Through such an arrangement, during the light-emitting process of the light-emitting device, the guest material can not only receive the energy transmitted by the excited group complex formed by the first main material and the second main material, but also receive the energy transmitted by the excited group complex formed by the hole transport functional material and the second main material. The energy transmission efficiency can be effectively improved, the energy utilization rate can be improved, and the efficiency of the light-emitting device can be effectively improved.

[0041] In some embodiments, the interface between the hole transport functional layer and the light emitting layer includes a first exciplex and a second exciplex.

[0042] 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.

[0043] In some embodiments, under a preset electric field strength, a ratio of an electron mobility of the second host material to a hole mobility of the first host material is greater than or equal to 10 and less than or equal to 1000.

[0044] 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.

[0045] 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.

[0046] In some embodiments, the first host material is selected from any one of the structures shown in formula (I).

[0047]

[0048] 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.

[0049] In some embodiments, the second host material is selected from any one of the structures represented by formula (II).

[0050]

[0051] 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.

[0052] In some embodiments, the hole transport functional material is selected from any one of the structures represented by general formula (III).

[0053]

[0054] 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 dibenzothienylene. 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 dibenzothienylene, 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.

[0055] 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.

[0056] In some embodiments, a mass 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.

[0057] 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.

[0058] In another aspect, a display panel is provided. The display panel comprises a plurality of light-emitting devices as described in 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 used to drive the light-emitting device to emit light.

[0059] The beneficial effects that can be achieved by the display panel provided by some embodiments of the present disclosure are the same as the beneficial effects that can be achieved by a light-emitting device provided by the above technical solution, and will not be repeated here.

[0060] In another aspect, a display device is provided. The display device comprises 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.

[0061] The beneficial effects that can be achieved by the display device provided by some embodiments of the present disclosure are the same as the beneficial effects that can be achieved by a display panel provided by the above technical solution, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings required to be used in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the product involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of the signal, etc.

[0063] Figure 1 is a structural diagram of a display device according to some embodiments;

[0064] Figure 2 is a structural diagram of a display panel according to some embodiments;

[0065] Figure 3 is a structural diagram of a light-emitting substrate according to some embodiments;

[0066] Figure 4 is a structural diagram of a light-emitting substrate according to some further embodiments;

[0067] Figure 5 is a structural diagram of a light emitting device according to some embodiments;

[0068] Figure 6 is a structural diagram of a light emitting device according to some further embodiments;

[0069] Figure 7 is a diagram of an energy transfer process according to some embodiments;

[0070] Figure 8 is a diagram of an energy transfer process according to some further embodiments;

[0071] Fig. 9 is a comparison diagram of exciton recombination areas according to some embodiments;

[0072] Fig.10 is a material distribution diagram at the interface between the hole transport functional layer and the light emitting layer according to some embodiments;

[0073] Fig.11 is a curve diagram showing changes in normalized exciton intensity at different positions in the light-emitting layer according to some embodiments;

[0074] Fig.12 is a HOMO electron cloud distribution diagram of a comparative material according to some embodiments;

[0075] Fig.13 is a photoluminescence spectrum diagram according to some embodiments;

[0076] Fig.14 is a HOMO electron cloud distribution diagram of a first host material according to some embodiments;

[0077] Fig.15 HOMO electron cloud distribution diagram of the first host material according to some further embodiments;

[0078] Fig.16 HOMO electron cloud distribution diagram of the first host material according to some further embodiments;

[0079] Fig.17 HOMO electron cloud distribution diagram of the first host material according to some other embodiments;

[0080] Fig.18 is a LUMO electron cloud distribution diagram of a second host material according to some embodiments;

[0081] Fig.19 is a LUMO electron cloud distribution diagram of a second host material according to some further embodiments;

[0082] Fig. 20 is a LUMO electron cloud distribution diagram of a second host material according to some further embodiments;

[0083] Fig.21LUMO electron cloud distribution diagram of the second host material according to some other embodiments. DETAILED DESCRIPTION

[0084] 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 described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0085] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and other forms thereof, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open, 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" and the like are intended to indicate that specific 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 specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0086] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, 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.

[0087] “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.

[0088] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0089] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of variation 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).

[0090] 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 the acceptable deviation range, wherein the acceptable deviation range is 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 a particular 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 may be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity may also be, for example, a deviation within 5°. "Equal" includes absolute equality and approximate equality, wherein the acceptable deviation range of approximate equality may be, for example, the difference between the two equalities is less than or equal to 5% of either one.

[0091] It will be understood that when a layer or an 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 between the layer or element and the other layer or substrate.

[0092] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of the layers and the area of ​​the regions are exaggerated for clarity. Therefore, variations in the shapes relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include shape deviations 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 shapes of the regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0093] It should be noted that, for example, 11-1 in the drawings of the present disclosure indicates that component 11 belongs to component 1, for example, Figure 2 220-200 indicates that the light-emitting functional layer 220 belongs to the light-emitting substrate 200, and other similar reference numerals in the drawings also follow the above description. For example, 1 / 2 in the drawings of the present disclosure indicates that structure 1 and structure 2 can refer to the structure, for example, Figure 3 The reference numeral 101 / 100 indicates that both the first light emitting device 100 and the light emitting device 101 can refer to this structure, and other similar reference numerals appearing in the drawings also follow the above description.

[0094] like Figure 1 As shown, some embodiments of the present disclosure provide a display device 400 , which includes: a display panel 300 .

[0095] The display device 400 may be, for example, an OLED (Organic Light Emitting Diode) display device 400 .

[0096] For example, Figure 1 As shown, the display device 400 further includes a driving chip 410. The driving chip 410 is used to drive the display panel 300 to display.

[0097] 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 a variety of different functions such as taking pictures, recording videos, fingerprint recognition or face recognition.

[0098] The display device 400 described above can be any display device that displays either motion (e.g., video) or fixed (e.g., still images) and whether text or images. More specifically, it is expected that the display device 400 of the embodiment described 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., odometer displays, etc.), navigators, cockpit controls and / or displays, displays of camera views (e.g., displays of rear-view cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging, and aesthetic structures (e.g., displays of images of a piece of jewelry), etc.

[0099] In some embodiments, Figure 2 As shown, 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, and the light-emitting functional layer 220 includes a plurality of light-emitting devices 100, and the plurality of light-emitting devices 100 are arranged along a first direction X, and the first direction X is parallel to the plane where the substrate 210 is located.

[0100] In some examples, such as Figure 2As shown, the display panel 300 further includes an array layer 310 disposed between the substrate 210 and the light-emitting functional layer 220, and 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, and is used to drive the light-emitting device 100 to emit light.

[0101] Exemplarily, 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, and the lights emitted by the multiple light emitting devices 100 cooperate with each other, so that the display panel 300 realizes the display function.

[0102] In some examples, such as Figure 2 As shown, 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 .

[0103] Exemplarily, the display panel 300 may be an OLED display panel, in which case the encapsulation layer 320 covers the light-emitting device 100 to encapsulate 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.

[0104] In some embodiments, Figure 2 and Figure 3 As shown, in the light-emitting substrate 200 , the light-emitting functional layer 220 further includes a pixel defining layer 221 disposed on one side of the substrate 210 . The pixel defining layer 221 has a plurality of openings Q. The plurality of light-emitting devices 100 can be disposed correspondingly to the plurality of openings Q one by one.

[0105] In some embodiments, Figure 3 and Figure 4 As shown, 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.

[0106] 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 (gray scale) 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.

[0107] It should be noted that Figure 4 This is a simplified schematic diagram obtained after removing other film layers in the light-emitting substrate 200 except for the film layers related to the light-emitting device 100. Figure 4 In the embodiment, the plurality of 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 .

[0108] In some embodiments, Figure 3 to Figure 5 As shown, the light emitting device 100 includes a first electrode 11 and a second electrode 12 which are stacked, and at least one light emitting unit 13 which is disposed between the first electrode 11 and the second electrode 12. The light emitting unit 13 includes a light emitting layer 131.

[0109] Exemplarily, 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 respectively, so that an electric field is generated between the two, which can drive the holes of the anode and the electrons of the cathode to recombine in the light-emitting layer 131, thereby emitting light.

[0110] In some examples, such as Figure 3 As shown, 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.

[0111] Exemplarily, 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, so that 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.

[0112] 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).

[0113] 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.

[0114] In some embodiments, Figure 6 As shown, in the light-emitting substrate 200, a cathode covering layer 15 is further provided between the encapsulation layer 320 and the second electrode 12. The material forming the cathode covering layer 15 is, for example, a material with a high refractive index. By providing the cathode covering layer 15, the high refractive property of the material can be utilized to improve the light extraction efficiency of the light-emitting device 100, and the efficiency and brightness of the light-emitting device 100 when lit can be improved.

[0115] It should be noted that Figure 6 This is a simplified schematic diagram obtained after removing other film layers in the display panel 300 except for the film layers related to the light emitting device 100. Figure 6 In the embodiment, the light emitting device 100 is, for example, a first light emitting device 101 .

[0116] In some examples, such as Figure 3 and Figure 4 As shown, the light emitting device 100 includes a 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, and the second direction Y intersects with the first direction X. In other examples, such as Figure 5 As shown, the light emitting device 100 includes a plurality of (for example, two) stacked light emitting units 13. At this time, the light emitting device 100 is a stacked light emitting device, and the first electrode 11, the plurality of light emitting units 13, and the second electrode 12 are stacked along the second direction Y.

[0117] For example, Figure 3 to Figure 5 As shown, the second direction Y is perpendicular to the first direction X.

[0118] In some embodiments, Figure 5 As shown, 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 , and the charge generation layer 14 is located between two adjacent light emitting units 13 among the plurality of light emitting units 13 .

[0119] Through the charge generation layer 14, the plurality of light-emitting units 13 can be sequentially connected in a direction perpendicular to the light-emitting surface (e.g., the second direction Y). Moreover, the charge generation layer 14 in the stacked OLED light-emitting device 100 not only plays a role in connecting the light-emitting units 13, but also helps to improve the generation efficiency of charges (holes or electrons), which can have a significant impact on the performance of the light-emitting device 100.

[0120] In some embodiments, Figure 3 to Figure 5 As shown, in order to improve the luminous efficiency of the light-emitting device 100, the light-emitting unit 13 also includes a hole transport functional layer 132, which is located on the side of the light-emitting layer 131 close to 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 hole injection layer 1321 (Hole Inject Layer, HIL) and a hole transport layer (Hole Transport Layer, HTL) arranged in a stacked manner. Among them, the hole transport layer (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 a hole injection layer 1321, a first hole transport layer 1322, and a 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 in a direction away from the first electrode 11, and the second hole transport layer 1323 contacts the light-emitting layer 131.

[0121] In some embodiments, Figure 3 to Figure 5 As shown, in order to improve the luminous efficiency of the light-emitting device 100, the light-emitting unit 13 also 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 an electron injection layer 1331, an electron transport layer 1332, and a 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.

[0122] 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 up 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 barrier height that needs to be overcome for carrier transition, thereby making the light-emitting efficiency higher.

[0123] Exemplarily, the hole transport functional layer 132 is configured to transport holes and / or to block electrons and excitons generated in the light-emitting layer 131. For example, the hole injection layer 1321 can be configured to reduce 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, block electrons and excitons generated in the light-emitting layer 131.

[0124] 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 .

[0125] In some embodiments, Figure 4 As shown, in the case where 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 a structure that is connected throughout the layer, that is, 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 a structure that is connected throughout the layer, that is, 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 a common film layer shared by the plurality of light-emitting devices 100, which will not be described in detail here.

[0126] For example, Figure 3 As shown, 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 .

[0127] In other embodiments, Figure 4 As shown, in the case where 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, so that 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.

[0128] 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.

[0129] Exemplarily, the first host material HP can be configured to: transport holes, and / or, recombining electrons and holes to form excitons, and transferring fluorescence resonance energy to the guest material D. At this time, the hole mobility of the first host material HP is greater than or equal to the hole mobility of the second host material HN.

[0130] Exemplarily, the second host material HN can be configured to: transport electrons, and / or, recombining electrons and holes to form excitons, and transfer fluorescence resonance energy to the guest material D. At this time, the electron mobility of the second host material HN is greater than or equal to the electron mobility of the first host material HP.

[0131] Exemplarily, 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 emit photons by forming excitons from recombined electrons and holes.

[0132] 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.

[0133] As mentioned in the background, in the field of organic semiconductors, OLED technology has attracted more and more attention from academia and industry, and has been successfully applied in commercial flat panel display and lighting industries. Among them, the guest material D, the first host material HP, and the second host material HN used in the light-emitting layer 131 of the OLED light-emitting device are different in compounds, which will have a great difference in the overall performance of the light-emitting device 100. With the development of OLED light-emitting devices, the performance requirements for the efficiency, service life, etc. of OLED light-emitting devices are getting higher and higher, and existing organic materials can hardly meet the requirements of OLED light-emitting devices.

[0134] 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.

[0135] 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 excited complex HP / HN, and the triplet energy level T1(HP / HN) of the excited 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 excited complex HP / HN can be higher than the triplet energy level T1(D) of the guest material D, thereby realizing energy transfer from the excited complex 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 base 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 transfer, and improving the efficiency of the light-emitting device 100.

[0136] 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, etc.

[0137] 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, etc.

[0138] 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 excited complex HT / HN with the second main material HN, and holes and electrons can recombine on the excited complex HT / HN to form excitons.

[0139] For example, in the first light-emitting device 101, the process of forming excitons on the exciplex HP / HN formed by the first host material HP and the second host material HN and transmitting energy to the guest material D is as follows: Figure 7As shown; the process of forming excitons on the exciplex HT / HN formed by the hole transport functional material HT and the second host material HN and transmitting energy to the guest material D is as shown Figure 8 shown.

[0140] Depend on Figure 7 and Figure 8 It can be seen that in 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 generate excitons, and the generated excitons are, for example, at least one of singlet excitons and triplet excitons. Among them, the singlet exciton energy can be transferred to the guest material D through Dexter energy transfer, and the triplet exciton energy can be transferred to the guest material D through Forster energy transfer. It should be noted that Figure 7 and Figure 8 In the figure, the lower box edge of the outer box of each material represents the highest occupied molecular orbital energy level HOMO of the material, and the upper box edge represents the lowest unoccupied molecular orbital energy level LUMO of the material; the left box edge and the right box edge are to form a closed schematic diagram and have no actual meaning. Figure 7 and Figure 8 In the figure, the guest material D and 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, and has no practical meaning.

[0141] In the related art, the light emitted by the light emitting diode is not of a single wavelength, but of a certain wavelength of the light emitted by the light diode, the light intensity is the highest. The peak wavelength (WLP) refers to the wavelength corresponding to the maximum luminous intensity or radiation power on the emission spectrum, also known as the maximum power wavelength, with the unit of nm (nanometer). The peak wavelength can reflect the spectral energy change of a light source and is an important measure for determining the effective output wavelength of the luminescent material.

[0142] 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. That is,

[0143] |WLP(HP / HN)-WLP(HT / HN)|≤10nm.

[0144] 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 and the peak wavelength WLP (D) of the absorption spectrum of the guest material D have a relatively high correspondence. 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.

[0145] When |WLP(HP / HN)-WLP(HT / HN)| is relatively large, the emission spectrum of the exciplex HT / HN formed by the hole transport functional material HT and the second host material HN is quite different from the emission spectrum of the exciplex HP / HN formed by the first host material HP and the second host material HN, which makes the energy transfer from the exciplex HT / HN to the guest material D relatively insufficient, which is easy to cause efficiency loss. When |WLP(HP / HN)-WLP(HT / HN)|≤10nm, the peak wavelength WLP(HT / 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 relatively close 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 main 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 main material HP and the second main 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 main 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.

[0146] In some examples, the emission spectrum of the exciplex HP / HN formed by the first host material HP and the second host material HN, and the emission spectrum of the exciplex HT / HN formed by the hole transport functional material HT and the second host material HN are as follows: Fig.13As shown in the figure. Wherein, ΔWLP refers to |WLP(HP / HN)-WLP(HT / HN)|. Fig.13 The ordinate in is 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 Fig.13 The emission spectrum shown in the figure is measured using a fluorescence spectrometer, and the measured luminescence intensity is the photoluminescence intensity. Here, photoluminescence 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, the excitation photon reaches the sample and is absorbed, and the process of photoexcitation occurs. Photoexcitation causes electrons to transition to an excited state, and then release energy (photons) when they return to a lower energy level through vibrational relaxation. The light emitted by this process is photoluminescence.

[0147] In some embodiments, under a preset 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 of (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 (volt / 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:

[0148]

[0149] It can be understood that when the electron mobility μ of the second host material HN e (HN), and the hole mobility μ of the first host material HP h When the ratio of (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 Thus, in the light-emitting layer 131 of the light-emitting unit 13, the migration rate of holes is relatively slow, and the migration rate of electrons is relatively fast, which can increase the imbalance between electron migration and hole migration; in this case, the region where holes and electrons in the light-emitting layer 131 recombine to form excitons can be located on the side close to the hole transport functional layer 132 (such as Fig. 9 The K1 position is shown in Figure 1).

[0150] Since at the interface between the hole transport functional layer 132 (for example, the second hole transport layer 1323) and the light emitting layer 131, Fig.10As shown, 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. Moreover, 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 area where holes and electrons in the light-emitting layer 131 recombine to form excitons is located on the side close to the hole transport functional layer 132 (such as Fig. 9 When the K1 position is shown in FIG, compared with the region where holes and electrons recombine to form excitons located in the middle of the light-emitting layer 131 (as shown in FIG. Fig. 9 In the case of the K2 position shown in FIG, holes and electrons can not only recombine to form excitons on the exciplex HP / HN, but also recombine to form excitons on the exciplex HT / HN. In this way, the energy utilization rate can be improved, and the efficiency of the light-emitting device 100 can be improved.

[0151] 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.

[0152] 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; 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.

[0153] 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, so that the exciton yield can be increased, and the luminous efficiency of the light-emitting device 100 is improved. 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 correspondingly, deeper hole traps are easily generated on the first host material HP. The hole transport layer 100 has a plurality of holes, each of which has a plurality of holes. The hole transport layer 100 has a plurality of holes, each of which has a plurality of holes. The hole transport layer 100 has a plurality of holes, each of which has a plurality of holes. The hole transport layer 100 has a plurality of holes, each of which has a plurality of holes. The hole transport layer 100 has a plurality of holes, each of which has a plurality of holes. The hole transport layer 100 has a plurality of holes, each of which has a plurality of holes. The hole transport layer 100 has a plurality of holes, each of which has a plurality of holes. The hole transport layer 100 has a plurality of holes, each of which has a plurality of holes. The hole transport layer 100 has a plurality of holes, each of which has a plurality of holes.

[0154] Illustratively, 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 may be 0.1 eV, 0.15 eV, 0.2 eV, 0.25 eV or 0.4 eV, etc.

[0155] 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 may be 0.1 eV, 0.15 eV, 0.2 eV, 0.3 eV or 0.4 eV, etc.

[0156] In some embodiments, the first host material is selected from any one of the structures shown in formula (I).

[0157]

[0158] 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.

[0159] 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.

[0160] n1 and n2 are the same or different and are independently selected from any one of 0 and 1.

[0161] n3 and n6 are the same or different and are independently selected from any one of 0, 1, 2, 3 and 4.

[0162] n4 and n5 are the same or different and are independently selected from any one of 0, 1 and 2.

[0163] 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 one of the values ​​greater than or equal to 1 in the selection range of nx.

[0164] It should be noted that when R1 or R2 is selected from any one of substituted phenyl, substituted biphenyl, substituted naphthyl, substituted carbazolyl, substituted dibenzofuranyl, substituted dibenzothiophenyl, substituted dimethylfluorenyl, substituted diphenylfluorenyl and substituted spirofluorenyl, the type and number of substituents are not limited here.

[0165] Among the above substituents, the structure of dimethylfluorenyl is, for example, The structure of diphenylfluorenyl is, for example, The structure of spirofluorene is, for example,

[0166] It should be noted that, in the general formula (I), It is a benzindolecarbazole group. 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 benzindolecarbazole group and R1 are directly connected by a covalent bond (for example, a single bond). When n2 is 0, the nitrogen in the benzindolecarbazole 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, you can refer to the above content and will not repeat it 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.

[0167] It can be understood that the structure shown in the general formula (I) above 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 function 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.

[0168] Moreover, in the case where the light-emitting device 100 is the first light-emitting device 101, since the first light-emitting device 101 emits red light, the corresponding wavelength is relatively large and the corresponding energy is relatively low compared to other light-emitting devices 100 (for example, the second light-emitting device 102), when the first main material HP contains a planar group, namely a benzoindolecarbazole group, the molecular rigidity of the first main material HP is relatively high and the molecular orientation is relatively high, so that the triplet energy level T1 (HP) of the first main material HP is relatively low, and the matching with the second main material HN and the guest material D of the light-emitting layer 131 of the first light-emitting device 101 is relatively better, so that the efficiency of the first light-emitting device 101 can be improved.

[0169] In addition, in the above general formula (I), the substituent of the benzindolecarbazole 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, so that the thermal stability of the first host material HP can be improved, and the life of the light-emitting device 100 can be improved.

[0170] An exemplary structure of the first host material HP having the structure represented by the general formula (I) is described below.

[0171] In some examples, when R2 is a naphthyl group, the structural formula of the first host material HP can be as shown below.

[0172]

[0173] In some examples, when R1 is a dibenzofuranyl group, the structural formula of the first host material HP may be as shown below.

[0174]

[0175] In some examples, when R1 is a carbazole group, the structural formula of the first host material HP may be as shown below.

[0176]

[0177] It should be noted that the above-listed structural formula is an example of the structure of the first host material HP, and is not a limitation on the first host material HP. Moreover, (HP1-x) in the above structural formula is a synonym for each structural formula, and is not a part of the structural formula structure, where x is a positive integer.

[0178] In some embodiments, the second host material is selected from any one of the structures represented by formula (II).

[0179]

[0180] 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.

[0181] 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.

[0182] n7, n8 and n9 are the same or different and are independently selected from any one of 0 and 1.

[0183] It should be noted that the description of n7, n8 and n9 here can refer to the description of n1 and n2 above, and will not be repeated here. Among them, n7, n8 and n9 are the same, which means that n7, n8 and n9 are the same. Except for the above-mentioned same situations, other situations are different.

[0184] 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 benzodibenzothiophenylene, substituted carbazolyl, substituted benzocarbazolyl and substituted phenanthroxazolyl, the type and number of substituents are not limited here.

[0185] 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 main material HN has a higher electron transport performance and can play the function of an electronic main body. In this way, during the light-emitting process of the light-emitting device 100, the first main material HP and the second main material HN can form an exciton complex HP / HN, which transfers the exciton energy to the guest material D, thereby achieving the purpose of emitting light and improving the efficiency of the light-emitting device 100.

[0186] 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. Compared with other light-emitting devices 100 (for example, the second light-emitting device 102), the first light-emitting device 101 emits red light, the corresponding wavelength is relatively small, and the corresponding energy is relatively high. When the second host material HN contains 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.

[0187] An exemplary structure of the second host material HN having the structure represented by the general formula (II) is described below.

[0188] 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 may be as shown below.

[0189]

[0190] 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 may be as shown below.

[0191]

[0192] It should be noted that the above-listed structural formulas are examples of the structure of the second host material HN, and are not limitations on the second host material HN. Moreover, (HN1-x) in the above structural formulas is a synonym for each structural formula, and is not a part of the structural formula structure, where x is a positive integer.

[0193] In some embodiments, the hole transport functional material is selected from any one of the structures represented by general formula (III).

[0194]

[0195] 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.

[0196] 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.

[0197] n 10 、n 11 and n 12 are the same or different, and are independently selected from any one of 0 and 1.

[0198] 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; it will not be repeated here.

[0199] 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 dibenzothienylene, and / or R6, R7 and R8 are selected from any one of substituted phenyl, substituted biphenylene, substituted naphthyl, substituted dibenzofuranyl, substituted dibenzothienyl, substituted dimethylfluorenyl, substituted diphenylfluorenyl, substituted spirofluorenyl and substituted adamantyl, the type and number of substituents are not limited here.

[0200] 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 triarylamine-type hole-type material, 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.

[0201] Moreover, based on the structure shown in the general formula (III), the hole transport functional material HT can form an excited complex HT / HN with the second main material HN. In this way, during the light emission 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 main material HP and the second main 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 main 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.

[0202] An exemplary structure of the hole transport functional material HT having the structure represented by the general formula (III) is described below.

[0203] 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.

[0204]

[0205]

[0206] It should be noted that the above-listed structural formulas are examples of the structure of the hole transport functional material HT, and are not limitations on the hole transport functional material HT. Moreover, (HT-x) in the above structural formulas is a synonym for each structural formula, and is not a part of the structural formula structure, where x is a positive integer.

[0207] 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.

[0208] 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.

[0209] 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 dibenzothiophene, deuterium-substituted dimethylfluorenyl, deuterium-substituted diphenylfluorenyl and deuterium-substituted spirofluorenyl.

[0210] 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 dibenzothienylene, deuterium-substituted benzodibenzothienylene, 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 dibenzofuranyl, deuterium-substituted benzodibenzofuranyl, deuterium-substituted dibenzothienyl, deuterium-substituted benzodibenzothienyl, deuterium-substituted carbazolyl, deuterium-substituted phenylene, deuterium-substituted biphenylene, deuterium-substituted naphthylene, deuterium-substituted di ... 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 dibenzothienyl, deuterium-substituted benzodibenzothienyl, deuterium-substituted carbazolyl, deuterium-substituted benzocarbazolyl and deuterium-substituted phenanthroxazolyl.

[0211] 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) 10 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 naphthyl, deuterium-substituted dibenzofuranyl, deuterium-substituted dibenzothiophenylene, deuterium-substituted dimethylfluorenyl, deuterium-substituted diphenylfluorenyl, deuterium-substituted spirofluorenyl and deuterium-substituted adamantyl.

[0212] The deuterium-substituted phenylene group refers to a phenylene group in which at least one hydrogen atom is replaced by a deuterium atom. For the understanding of deuterium-substituted biphenylene group, deuterium-substituted naphthyl group, etc., reference can be made to the above content and will not be repeated here.

[0213] 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 one side (such as the second hole transport layer 1323) close to the hole transport functional layer 132 (for example, the second hole transport layer 1323), Fig. 9 When the hole transport functional layer 132 (for example, the second hole transport layer 1323) is at the interface with the light-emitting layer 131, the exciton density is relatively high, 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.

[0214] It can be understood that, since the atomic weight of deuterium is twice that of hydrogen, by setting 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 (for example, the first light-emitting device 101), and / or the material of the hole transport functional layer 132 (for example, the second hole transport layer 1323) will change. Specifically, when the first host material HP and the second host material HT are substituted by deuterium, and / or the hole transport functional material HT is substituted by deuterium, the molecular vibration can be effectively suppressed, the bond length can be reduced, the molecular exciton stability can be improved, and the molecular stability can be improved. In this way, the thermal stability of the material of the light-emitting layer 131 of the light-emitting device 100 (for example, the first light-emitting device 101), and / or the material of the hole transport functional layer 132 (for example, the second hole transport layer 1323) is improved, and the life of the light-emitting device 100 (for example, the first light-emitting device 101) can be improved.

[0215] In some examples, the first host material HP, the second host material HT and the hole transport functional material HT are all deuterated materials. In this way, the thermal stability of the material of the light-emitting layer 131 of the light-emitting device 100 (for example, the first light-emitting device 101) and the material of the hole transport functional layer 132 (for example, the second hole transport layer 1323) is improved, and the life of the light-emitting device 100 (for example, the first light-emitting device 101) can be increased.

[0216] 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.

[0217] It should be noted that 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, which means that the mass ratio of the first main material HP to the second main material HN 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.

[0218]

[0219] 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 transfer rate and the hole transfer 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.

[0220] 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.

[0221] The above is an exemplary introduction to the material of the light-emitting layer 131 and the material of the hole transport functional layer 132 when the first host material HP contains a benzindolecarbazole group. The above material system can improve the efficiency of the light-emitting device 100 and increase the life of the light-emitting device 100. The above light-emitting device 100 is, for example, the first light-emitting device 101. The following is an exemplary introduction to the material of the light-emitting layer 131 when the first host material HP contains a triarylamine structure.

[0222] In some implementations, in the exciton recombination region of the light-emitting layer 131 of the light-emitting device 100 (for example, the first light-emitting device 101), triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ) are likely to occur, resulting in a reduction in the number of excitons. Moreover, the triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ) phenomena are more serious at high current density (high grayscale), making the luminous efficiency at high current density (high grayscale) lower than that at low current density (low grayscale), resulting in the problem of efficiency roll-off at high current density.

[0223] In the above implementation, the region where triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ) occur is, for example, a region close to the hole transport functional layer 132. In this case, the normalized exciton intensity at each position along the second direction Y in the light-emitting layer 131 is, for example, Fig.11 As shown. Among them, Fig.11The normalized exciton intensity in refers to the exciton intensity at the measurement point corresponding to the highest exciton intensity being normalized to 1. Fig.11 It can be seen that, compared with the middle position of the light-emitting layer 131 and the position of the light-emitting layer 131 close to the electron transport functional layer 133 , the exciton intensity is relatively high on the side of the light-emitting layer 131 close to the hole transport functional layer 132 .

[0224] In the 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 the first preset current density I1 and the normalized current efficiency E2′ of the light-emitting device 100 at the 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:

[0225]

[0226] 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:

[0227]

[0228] 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: by measuring the change curve of the current efficiency E with the current density I, 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.

[0229] 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 15 mA / cm 2 .

[0230] In some embodiments, the first host material is selected from any one of the structures shown in formula (IV);

[0231]

[0232] Wherein, L9 is 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.

[0233] 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 of X1, X2, X3, X4 and X5.

[0234] 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.

[0235] R a Any one selected from hydrogen and deuterium.

[0236] Ar1 is selected from any one of Ar1-a to Ar1-i.

[0237]

[0238] 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

[0239] B(R i )

[0240] 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 , R27 , 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, each 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.

[0241] n 13 、n 16 、n 18 、n 20 and n 22 are the same or different and are independently selected from any one of 0, 1 and 2.

[0242] 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.

[0243] 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, and x is a positive integer, and the same applies below. For the understanding of other arylene groups such as Cx, reference can be made to the above content, which will not be repeated here. For the understanding of alkylene, arylene and heteroarylene, reference can be made to the above content of phenylene, which 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, there is no limitation on the type and number of substituents.

[0244] 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.

[0245] 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 ) Any of the following four situations:

[0246] (1)X a and X b X1 and X2; and X3, X4 and X5 are independently selected from N and C (R a )

[0247] (2)X a and X b X2 and X3; and X1, X4 and X5 are independently selected from N and C (R a )

[0248] (3)X a and X b are X3 and X4; and X1, X2 and X5 are independently selected from N and C (R a )

[0249] (4)X a and X b are X4 and X5; and X1, X2 and X3 are independently selected from N and C (R a )

[0250] 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 ) wherein O is oxygen; S is sulfur; Se is selenium; C=O is a carbonyl group;

[0251] 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.

[0252] 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 iWhen the substituent is selected from any one of substituted alkyl, substituted cycloalkyl, substituted alkoxy, substituted aryloxy, substituted alkylthio, substituted arylthio, substituted alkylsulfonyl, substituted arylsulfonyl, substituted alkenyl, substituted silyl, substituted boron, substituted amine, substituted arylphosphino, substituted phosphine, substituted aryl, substituted heteroaryl and substituted heterocyclic, the type and number of the substituent are not limited herein.

[0253] It should be noted that R9, R 10 , R 11 , R 12 and R 13 In the case of R, two adjacent Rs may or may not be bonded to form a ring; 14 , R 15 , R 16 , R 17 and R 18 In the case of n, two adjacent pairs may or may not be bonded to form a ring; 13 When 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 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 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 two R 26 It can be bonded to form a ring or not; in n 21 When the value of two adjacent R 27 It can be bonded to form a ring or not; in n 22 When 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.

[0254] It should be noted that in the structure shown in the 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.

[0255] 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 understanding 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 Ar1 and Ar2 are X3 and X4, the structural formula after fusion is as shown below.

[0256]

[0257] It can be understood that, since in the structure shown in the general formula (IV), Ar2, Ar3 and Ar4 are all aromatic groups, the first host material HP is a hole-type material of the triarylamine type, so that the HOMO electron cloud of the first host material HP can 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, so as to balance the carrier distribution, reduce the probability of triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ), reduce exciton quenching, and alleviate 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 (such as a phosphorescent material) to achieve the purpose of emitting light, thereby improving the efficiency of the light-emitting device 100 (such as the first light-emitting device 101).

[0258] In order to verify the hole transport performance of the first host material HP, a comparative material was designed and the HOMO electron cloud distribution of the comparative material was calculated. The results are as follows: Fig.12 As shown. Among them, one side of the structural formula of the comparative material (such as Fig.12 The left side (shown in Figure 2) is a triarylamine molecular fragment, and the other side (shown in Figure 2) is a triarylamine molecular fragment. Fig.12 The right side of the figure is an indolecarbazole molecular fragment, and the triarylamine molecular fragment and the indolecarbazole molecular fragment are connected by an alkyl group to interrupt the possible conjugation between the triarylamine structure and the indolecarbazole structure. The calculation results of the HOMO electron cloud distribution are obtained by using the density functional B3LYP / 6-31G(d) method using Gaussian calculation software and optimizing the ground state structure of the molecule.

[0259] Depend on Fig.12 It can be seen that in the comparison material containing triarylamine molecular fragments and indolecarbazole molecular fragments, the distribution of HOMO electron cloud is mainly concentrated on the side of the triarylamine molecular fragment. It can be seen that compared with the indolecarbazole molecular fragment, the triarylamine molecular fragment has a relatively stronger electron donation ability, indicating that compared with the hole-type material containing the indolecarbazole structure, the hole transport performance of the first host material HP containing the triarylamine structure is relatively higher; correspondingly, the hole mobility is also relatively higher.

[0260] An exemplary structure of the first host material HP having a structure represented by general formula (IV) is described below.

[0261] In some examples, when Ar1 is Ar1-a, the structural formula of the first host material HP may be as shown below.

[0262]

[0263] In some examples, when Ar1 is Ar1-b, the structural formula of the first host material HP may be as shown below.

[0264]

[0265]

[0266] In some examples, when Ar1 is Ar1-c, the structural formula of the first host material HP may be as shown below.

[0267]

[0268] In some examples, when Ar1 is Ar1-d, the structural formula of the first host material HP may be as shown below.

[0269]

[0270] In some examples, when Ar1 is Ar1-e, the structural formula of the first host material HP may be as shown below.

[0271]

[0272] In some examples, when Ar1 is Ar1-f, the structural formula of the first host material HP may be as shown below.

[0273]

[0274] In some examples, when Ar1 is Ar1-g, the structural formula of the first host material HP may be as shown below.

[0275]

[0276] In some examples, when Ar1 is Ar1-h, the structural formula of the first host material HP may be as shown below.

[0277]

[0278] In some examples, when Ar1 is Ar1-i, the structural formula of the first host material HP may be as shown below.

[0279]

[0280]

[0281] It should be noted that the above-listed structural formulas are examples of the structure of the first host material HP, and are not limitations on the first host material HP. Moreover, (HP2-x) in the above structural formulas is a synonym for each structural formula, and is not a part of the structural formula structure, where x is a positive integer.

[0282] In some embodiments, 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 bonds to form a ring.

[0283] It is understandable that when R9, R 10 , R 11 , R 12 and R 13 When two adjacent bonds in the first host material HP are formed into a ring, Ar3 can be fused with the bonded ring, so that a planar group with a larger area can be formed at Ar3 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transfer, and improve the efficiency of the light-emitting device 100.

[0284] In some embodiments, 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 bonds to form a ring.

[0285] It is understandable that when R 14 , R 15 , R 16 , R 17 and R 18 When two adjacent bonds in the first host material HP are formed into a ring, Ar4 can be fused with the bonded ring, so that a planar group with a larger area can be formed at Ar4 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0286] In some embodiments, at n 13When the two R 19 Bond to form a ring.

[0287] 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, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0288] In some embodiments, at 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.

[0289] 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, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0290] In some embodiments, at 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.

[0291] It is understandable that when n 15 Two adjacent Rs greater than or equal to 2 21When bonding to form a ring, Ar1 can be fused with the bonded ring, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0292] In some embodiments, at n 16 When the two R 22 Bond to form a ring.

[0293] It is understandable that when n 16 is 2 and two R 22 When bonding to form a ring, Ar1 can be fused with the bonded ring, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0294] In some embodiments, at 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.

[0295] 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, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0296] In some embodiments, at n 18 When the two R 24 Bond to form a ring.

[0297] It is understandable that when n18 is 2 and two R 24 When bonding to form a ring, Ar1 can be fused with the bonded ring, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0298] In some embodiments, at 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.

[0299] 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, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0300] In some embodiments, at n 20 When the two R 26 Bond to form a ring.

[0301] 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, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0302] In some embodiments, at n 21 When it is greater than or equal to 2, every two adjacent R 27As a group, at least one group is bonded to form a ring.

[0303] 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, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0304] In some embodiments, at n 22 When the two R 28 Bond to form a ring.

[0305] 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, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0306] In some embodiments, at 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.

[0307] 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, so that a planar group with a larger area can be formed at Ar1 of the first host material HP, making the molecular rigidity of the first host material HP relatively high. In this way, the triplet energy level T1(HP) of the first host material HP can be relatively low, and 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 can be relatively small, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0308] In the related art, compared with the CN single bond in the carbazole structure and the CC single bond in the biphenyl structure, the bond dissociation energy of the CN single bond in the triarylamine structure is relatively low, making the stability of the triarylamine structure relatively poor. For example, as shown in the following formula, the bond dissociation energy of the CN single bond in the triarylamine structure is 3.31 eV, the bond dissociation energy of the CN single bond in the carbazole structure is 3.71 eV, and the bond dissociation energy of the CC single bond in the biphenyl structure is 5.03 eV.

[0309]

[0310] 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.

[0311] 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. In the case where 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, L9 is a deuterated group.

[0312] 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.

[0313] It is understandable that when R9, R 10 , R 11 , R 12 and R 13 When at least one of R is deuterium, Ar3 is a six-membered ring substituted with deuterium. 14 , R 15 , R 16 , R 17 and R 18When 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. In the case where 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 (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 settings, 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.

[0314] 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 can be 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.

[0315] In some embodiments, when L9 is a single bond, the ratio of the number of deuteriums to the total number of hydrogens to the total number of deuteriums 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 deuteriums to the total number of hydrogens to the total number of deuteriums in Ar3, Ar4 and L9 is greater than or equal to 50%.

[0316] That is, when L9 is a single bond, the number of hydrogen atoms 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 is N D-Ar4 , the number of hydrogen atoms in Ar2 is N H-Ar2 and the number of deuterium in Ar2 D-Ar2 , satisfying:

[0317]

[0318] 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 isH-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 is N D-Ar4 , the number of hydrogens in L9 is N H-L9 and the number of deuterium in L9 N D-L9 , satisfying:

[0319]

[0320] It can be seen that through the above arrangement, 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 deuterium is greater than or equal to 50%.

[0321] 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, so that the suppression effect of the molecular vibration at the position of the nitrogen 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, so that 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.

[0322] 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 Ar3, namely R x The number of deuterium in Ar3 is accumulated and counted into the number of deuterium in Ar3. x When it is a planar group, R x The hydrogen in Ar3 does not constitute part of the hydrogen in R x The number of hydrogens in R is accumulated and not included in the number of hydrogens in Ar3; x The deuterium in Ar3 does not constitute part of the deuterium in R x The number of deuterium in R is cumulative and not included in the number of deuterium in Ar3. x For R9, R 10 , R 11 , R 12 and R 13It 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 hydrogens and the number of deuteriums in Ar2, Ar4 and L9, reference can be made to the above content, which will not be repeated here.

[0323] In some examples, when L9 is a single bond, the number of deuteriums in Ar3, Ar4 and Ar2, and the ratio of the number of hydrogens to the total number of deuteriums, is greater than or equal to 70%. 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 deuteriums in Ar3, Ar4 and L9, and the ratio of the number of hydrogens to the total number of deuteriums, is greater than or equal to 70%.

[0324] Exemplarily, when 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 can be 50%, 60%, 75%, 80%, 90% or 100%, etc.

[0325] Exemplarily, 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 deuterium in Ar3, Ar4 and L9, and the ratio between the number of hydrogen and the total number of deuterium can be 50%, 65%, 75%, 80%, 95% or 100%, etc.

[0326] In some embodiments, the second host material is selected from any one of the structures shown in formula (V).

[0327]

[0328] 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.

[0329] X6, X7, X8, X9 and X 10 are 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.

[0330] 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 connected with an adjacent substituent to form a substituted or unsubstituted ring.

[0331] R 30 and R 31 The same or different, each 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.

[0332] n 24 and n 25 The same or different, each independently selected from any one of 0, 1, 2, 3, 4 and 5.

[0333] 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.

[0334] It should be noted that here L 10 The description of L9 can be referred to above; the description of Cx here can be referred to above, and x is a positive integer; the description of arylene etc. here can be referred to above for the description of phenylene; 24 and n 25 The description of n can be found in the above 19 description; it will not be repeated here.

[0335] 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 30and R 31 When the substituent is selected from any one of substituted alkyl, substituted cycloalkyl, substituted alkoxy, substituted aryloxy, substituted alkylthio, substituted arylthio, substituted alkylsulfonyl, substituted arylsulfonyl, substituted alkenyl, substituted silyl, substituted boronyl, substituted amine, substituted arylphosphino, substituted phosphine oxide, substituted aryl, substituted heteroaryl and substituted heterocyclic groups, the type and number of the substituent are not limited herein.

[0336] 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 main material HN has a higher electron transport performance and can play the function of an electronic main body. In this way, during the light-emitting process of the light-emitting device 100, the first main material HP and the second main 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).

[0337] Moreover, when the light-emitting device 100 is the first light-emitting device 101, in the structure shown in the above general formula (V), Ar5, Ar6 and Ar7 are all planar groups, and 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 small wavelength and a relatively high energy relative to other light-emitting devices 100 (for example, the second light-emitting device 102), when the second host material HN contains the above planar groups, the triplet energy level T1 (HN) of the second host material HN is relatively low, and the matching property 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, so that the efficiency of the first light-emitting device 101 can be improved.

[0338] 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.

[0339] 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, so that a planar group with a larger area can be formed 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, which can improve the energy transfer efficiency, enhance the sufficiency of energy transfer, and improve the efficiency of the light-emitting device 100.

[0340] In some embodiments, at 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.

[0341] It is understandable that when n 24 Greater than or equal to 2, and two adjacent R 30 When bonding to form a ring, Ar5 can be fused with the bonded ring, so that a planar group with a larger area can be formed at Ar5 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, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0342] In some embodiments, at 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.

[0343] 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 be fused with the bonded ring, so that a planar group with a larger area can be formed at Ar6 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, which can improve the energy transfer efficiency, enhance the sufficiency of energy transmission, and improve the efficiency of the light-emitting device 100.

[0344] 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 main material HN, resulting in a high electron distribution density on the second main material HN, which can easily lead to the degradation of the second main material HN, and have an adverse effect on the molecular stability of the second main material HN and the life of the light-emitting device 100.

[0345] In order to improve the stability of the second host material HN, in some embodiments, 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 Among them, at least one is a deuterated group.

[0346] Understandably, in L 10 When L is a single bond, the three parts directly connected to the triazine group in the structure of the second host material HN 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 In the case of 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.

[0347] As mentioned above, the structure of the deuterated group contains at least one deuterium atom. When at least one of the three parts directly connected to the triazine group is a deuterated structure, in the structure of the second host material HN, at least one of the three parts directly connected to the triazine group contains deuterium. Since the atomic weight of deuterium is twice the atomic weight of hydrogen, by setting at least one of the three parts directly connected to the triazine group containing deuterium, the molecular vibration at the position of the triazine group in the structure of the second host material HN can be effectively suppressed, so that the molecular stability of the triazine group is improved, so that the thermal stability of the second host material HN can be improved, and the life of the light-emitting device 100 can be increased.

[0348] In some embodiments, in the structure represented by general formula (V), in the deuterated group, the ratio between the number of hydrogen atoms and the sum of the number of hydrogen atoms and the number of deuterium atoms is greater than or equal to 20%.

[0349] That is, when Ar5 is a deuterated group in the structure shown in general formula (V), the number of hydrogen atoms in Ar5 is H-Ar5 , the number of deuterium in Ar5 is N D-Ar5 , satisfying:

[0350]

[0351] In the case where Ar6 is a deuterated group in the structure represented by general formula (V), the number of hydrogen atoms in Ar6 is H-Ar6 , the number of deuterium in Ar6 N D-Ar6 , satisfying:

[0352]

[0353] In the case where Ar7 is a deuterated group in the structure represented by general formula (V), the number of hydrogen atoms in Ar7 is H-Ar7 , the number of deuterium in Ar7 N D-Ar7 , satisfying:

[0354]

[0355] 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:

[0356]

[0357] 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 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,

[0358] 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.

[0359] 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; it will not be repeated here.

[0360] It can be understood that in the structure shown in the general formula (V), when the ratio between the number of hydrogen in the deuterated group and the total number of hydrogen and deuterium is greater than or equal to 20%, compared with the case where the ratio between the number of hydrogen in the deuterated group and the total number of hydrogen and deuterium is less than 20%, the deuterium content in the three parts directly connected to the triazine group in the second main material HN is relatively high, so that 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 main material HN is relatively higher, so that the life of the light-emitting device 100 can be improved.

[0361] In some examples, in the structure represented by general formula (V), in the deuterated group, the ratio between the number of hydrogen atoms and the sum of the number of hydrogen atoms and the number of deuterium atoms is greater than or equal to 40%.

[0362] Illustratively, 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.

[0363] An exemplary structure of the second host material HN having the structure represented by the general formula (V) is described below.

[0364] 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.

[0365]

[0366]

[0367] 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.

[0368]

[0369] 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.

[0370]

[0371] In some examples, when the second host material HN includes a benzocarbazole group, the structural formula of the second host material HN may be as shown below.

[0372]

[0373] 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.

[0374]

[0375] 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.

[0376]

[0377] It should be noted that the above-listed structural formulas are examples of the structure of the second main material HN, and are not limitations on the second main material HN. Moreover, (HN2-x) in the above structural formulas is a synonym for each structural formula, and is not a part of the structural formula structure, where x is a positive integer.

[0378] 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.

[0379] Exemplarily, 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).

[0380] It should be noted that 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, which means that the mass ratio of the first main material HP to the second main material HN 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:

[0381]

[0382] 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, and 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, 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.

[0383] 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.

[0384] 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.

[0385] In some embodiments, the light emitting device is configured to emit light of a first wavelength, and 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.

[0386] Exemplarily, the chromaticity coordinate CIEx of the red light is 0.678, 0.680, 0.681, 0.682, 0.683 or 0.684, etc.

[0387] Exemplarily, the chromaticity coordinate CIEy of the red light is 0.316, 0.317, 0.319, 0.320, 0.321 or 0.323, etc.

[0388] In order to objectively evaluate the technical effects of the embodiments of the present disclosure, the technical solutions provided by the present disclosure are described in detail and exemplarily through the following experimental examples and comparative examples. 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.

[0389] The first set of test cases

[0390] The following embodiments 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, 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.

[0391] 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.

[0392] 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.

[0393] For example, Figure 6 As shown, the preparation method of the light-emitting substrate 200 including the 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. Before use, the back plate is firstly ultrasonically treated in deionized water and then dried at 100°C.

[0394] It should be noted that the thickness and material 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 completely the same. Among them, in the material 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.

[0395]

[0396] The material of the light-emitting layer 131 in the following comparative example includes a comparative first host material I and a comparative second host material I, and the material of the second hole transport layer 1323 includes 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).

[0397]

[0398] 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.

[0399] 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 respectively.

[0400] 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 as (HP1-1); the structural formula of the second host material HN is shown as (HN1-1); the structural formula of the material of the second hole transport layer 1323 is shown as (HT-1). Moreover, the mass ratio between the first host material HP and the second host material HN is 4:6; the mass ratio between the guest material D and the host material (including the first host material HP and the second host material HN) is 2%.

[0401] 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); the structural formula of the material of the second hole transport layer 1323 is shown in (HT-2). Moreover, the mass ratio between the first host material HP and the second host material HN is 4:6; the mass ratio between the guest material D and the host material (including the first host material HP and the second host material HN) is 2%.

[0402] 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); the structural formula of the material of the second hole transport layer 1323 is shown in (HT-3). Moreover, the mass ratio between the first host material HP and the second host material HN is 4:6; the mass ratio between the guest material D and the host material (including the first host material HP and the second host material HN) is 2%.

[0403] 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 as (HP2-1); the structural formula of the second host material HN is shown as (HN-1); the structural formula of the material of the second hole transport layer 1323 is shown as (HT-1). Moreover, the mass ratio between the first host material HP and the second host material HN is 4:6; the mass ratio between the guest material D and the host material (including the first host material HP and the second host material HN) is 2%.

[0404] 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); the structural formula of the material of the second hole transport layer 1323 is shown in (HT-1). Moreover, the mass ratio between the first host material HP and the second host material HN is 4:6; the mass ratio between the guest material D and the host material (including the first host material HP and the second host material HN) is 2%.

[0405] 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 as (HP2-11); the structural formula of the second host material HN is shown as (HN-1); the structural formula of the material of the second hole transport layer 1323 is shown as (HT-1). Moreover, the mass ratio between the first host material HP and the second host material HN is 4:6; the mass ratio between the guest material D and the host material (including the first host material HP and the second host material HN) is 2%.

[0406] 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); the structural formula of the hole transport functional material is shown as (R-HT). Moreover, the mass ratio between the first host material HP and the second host material HN is 4:6; the mass ratio between the guest material D and the host material (including the first host material HP and the second host material HN) is 2%.

[0407] 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 embodiments and the comparative examples, 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 embodiments and the comparative examples.

[0408] Table 1

[0409] First main material Second main material Hole transport functional materials Example 1 HP1-1 HN1-1 HT-1 Example 2 HP1-2 HN1-3 HT-2 Example 3 HP1-3 HN1-2 HT-3 Example 4 HP2-1 HN1-1 HT-1 Example 5 HP2-5 HN1-1 HT-1 Example 6 HP2-11 HN1-1 HT-1 Comparative Example 1 R-HP R-HN R-HT

[0410] It should be noted that "Ax" in Table 1 refers to the corresponding structural formula Ax. For example, the content of 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 refer to the above content and will not be repeated here.

[0411] 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 excited complexes are shown in Table 2.

[0412] Table 2

[0413]

[0414]

[0415] 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. "Migration @ 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.

[0416] Based on the above materials, the voltage (V), current efficiency (cd / A), color of emitted light and device life of the first light emitting device 101 of Examples 1 to 6 and Comparative Example 1 were tested. The data results of voltage (V), current efficiency (cd / A) and device life are based on Example 1, and the test results are shown in Table 3 below. The device life is characterized by the parameter LT95; the color of the emitted light is represented by the chromaticity coordinates CIEx and CIEy in the CIE chromaticity diagram.

[0417] Table 3

[0418]

[0419]

[0420] It can be seen from Table 3 that in Examples 1 to 6 and Comparative Example 1, the chromaticity coordinates CIEx of the color of the emitted light of 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 emitted light of 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.

[0421] Compared with Comparative Example 1, please refer to Table 3. The current efficiency of Examples 1 to 6 is relatively high. This is because the highest occupied molecular orbital energy level HOMO (R-HT) of the comparative hole transport functional material R-HT in Comparative Example 1 is higher than the highest occupied molecular orbital energy level HOMO (HT) of the hole transport functional material HT in Examples 1 to 6, so that the energy of the excitons generated by the exciplex (R-HT) / (R-HN) formed by the comparative hole transport functional material R-HT and the comparative second host material IR-HN is 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, resulting in the peak wavelength of the exciplex (R-HT) / (R-HN) formed by the comparative hole transport functional material R-HT and the comparative second host material IR-HN being blue-shifted to 492nm. In this way, the difference between the peak wavelength of the exciplex (R-HT) / (R-HN) formed by the comparative hole transport functional 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 is increased to 30nm, which is relatively high. In this way, the correspondence between the peak wavelength of the exciplex (R-HT) / (R-HN) formed by the comparative hole transport functional 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, which makes the energy utilization relatively low, and reduces the efficiency of the first light-emitting device 101.

[0422] Compared with Comparative Example 1, please refer to Table 3. The device lifespan of Examples 1 to 6 is relatively high. 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 functional 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 functional material R-HT are all materials that do not contain deuterium atoms. Since the atomic weight of deuterium is twice that of hydrogen, molecular vibration can be effectively suppressed, so that the molecular stability of the first host material HP, the second host material HN, and the hole transport functional material HT is improved. In this way, the thermal stability of the first host material HP, the second host material HN, and the hole transport functional material HT can be improved, and the device life of the first light-emitting device 101 can be increased. Compared with Examples 1 to 3, the device lifespan of Examples 4 to 6 is relatively higher. 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 higher.

[0423] 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 excited complex 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 excited complex HT / HN formed by the hole transport functional material HT and the second host material HN, is less than or equal to 10nm. In 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. At the same time, the present invention 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).

[0424] The second group of test cases

[0425] The following embodiments 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 15 mA / cm 2 .

[0426] 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.

[0427] 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.

[0428] For example, Figure 6 As shown, the preparation method of the light-emitting substrate 200 including the first light-emitting device 101 is as follows: the substrate 210 provided with the array layer 310, the pixel defining layer 221 and the first electrode 11 (the material of the first electrode 11 is indium tin oxide) is used as the 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.

[0429] It should be noted that the thickness and materials of the first electrode 11, 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 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, 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 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 completely the same. Among them, in the materials of the light-emitting layer 131, the guest material D is the same, and the guest material D is Ir(piq)3, and the structure is shown in the following formula, and the structures of the first host material HP and the first host material HN are different.

[0430]

[0431] 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.

[0432] The materials of the light-emitting layer 131 in the following comparative example 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).

[0433]

[0434] 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.

[0435] 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.

[0436] In Example 7, the light-emitting layer 131 includes a first host material HP, a second host material II and a guest material D. The structural formula of the first host material HP is shown as (HP2-7); the structural formula of the second host material II is shown as (R-HN2). Moreover, the mass ratio of the first host material HP, the second host material II and the guest material D is 49:49:2.

[0437] 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 in (R-HP2-1); the structural formula of the second host material HN is shown in (HN2-1). Moreover, the mass ratio of the first host material II, the second host material HN, and the guest material D is 49:49:2.

[0438] 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); the structural formula of the second host material HN is shown in (HN2-1). Moreover, the mass ratio of the first host material HP, the second host material HN and the guest material D is 49:49:2.

[0439] 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); the structural formula of the second host material HN is shown in (HN2-18). Moreover, the mass ratio of the first host material HP, the second host material HN and the guest material D is 49:49:2.

[0440] 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); the structural formula of the second host material HN is shown in (HN2-16). Moreover, the mass ratio of the first host material HP, the second host material HN and the guest material D is 49:49:2.

[0441] 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); the structural formula of the second host material HN is shown in (HN2-19). Moreover, the mass ratio of the first host material HP, the second host material HN and the guest material D is 49:49:2.

[0442] 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); the structural formula of the second host material HN is shown in (HN2-1). Moreover, the mass ratio of the first host material HP, the second host material HN and the guest material D is 59:39:2.

[0443] 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); the structural formula of the second host material HN is shown in (HN2-1). Moreover, the mass ratio of the first host material HP, the second host material HN and the guest material D is 39:59:2.

[0444] In Comparative Example 2, the 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). Moreover, the mass ratio between the comparative first host material II, the comparative second host material II, and the guest material D is 49:49:2.

[0445] In Comparative Example 3, the 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). Moreover, the mass ratio between the comparative first host material III, the comparative second host material II, and the guest material D is 49:49:2.

[0446] 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 the 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 the comparative examples, as well as the mass ratios between the first host material HP, the second host material HN and the guest material D.

[0447] Table 4

[0448]

[0449]

[0450] It should be noted that "Ax" in Table 4 refers to the corresponding structural formula Ax. For example, the sub-grid content corresponding to the first host material HP in Example 4 is "HP2-7", which means that in the light-emitting layer 131 of Example 1, the structural formula of the first host material HP 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 refer to the above content and will not be repeated here.

[0451] Among them, the HOMO electron cloud distribution diagrams of the first host materials HP2-7, HP2-11, HP2-18, and HP2-22 are as follows: Figure 14 to Figure 17 The LUMO electron cloud distribution diagram of the second host materials HN2-1, HN2-16, HN2-18, and HN2-19 is shown in Figure 18 to Figure 21 The calculation results of the above HOMO electron cloud distribution and LUMO electron cloud distribution are obtained by using Gaussian calculation software using density functional B3LYP / 6-31G(d) method and optimizing the ground state structure of the molecule.

[0452] Based on the above materials, the voltage (V), current efficiency (cd / A), color of emitted light, device life and efficiency decay index ΔE of the first light emitting device 101 of Examples 7 to 14 and Comparative Examples 2 to 3 were tested. The data results of voltage (V), current efficiency (cd / A) and device life are based on Comparative Example 2, and the test results are shown in Table 5 below. The device life is characterized by the parameter LT95; the color of the emitted light is represented by the chromaticity coordinates CIEx and CIEy in the CIE chromaticity diagram.

[0453] Table 5

[0454]

[0455]

[0456] It can be seen from Table 5 that 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.

[0457] Compared with Comparative Examples 2 to 3, Examples 7 to 14, please refer to Table 3, the device life of Examples 7 to 14 is relatively long. This is because in the light-emitting layer 131 of the first light-emitting device 101 of Examples 7 to 14, the first host material HP and the second host material HN are both deuterated materials, while in Comparative Examples 2 to 3, the first host material IIR-HP2-1, the first host material III R-HP2-2, and the second host material II R-HN2 are all materials that do not contain deuterium atoms. Since the atomic weight of deuterium is twice that of hydrogen, it can effectively suppress molecular vibration, so that the molecular stability of the first host material HP and the second host material HN is improved. In this way, the thermal stability of the first host material HP and the second host material HN can be improved, and the device life of the first light-emitting device 101 can be increased.

[0458] Compared with Comparative Example 3, Example 7 to Example 14, please refer to Table 5, the efficiency decay index ΔE of Example 7 to Example 14 is relatively low. This is because in Example 7 to Example 14, the structure of the first host material HP includes a triarylamine structure, which can make the HOMO electron cloud of the first host material HP have a higher distribution density on the triarylamine structure, which can improve the hole mobility of the first host material HP, and move the exciton recombination area of ​​the light-emitting layer 131 of the first light-emitting device 101 to the middle position of the light-emitting layer 131, which can reduce the probability of triplet-triplet exciton annihilation (TTA) and triplet-polaron quenching (TPQ), reduce exciton quenching, and slow down the problem of efficiency decay (roll-off) 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.

[0459] Please refer to Table 5. The current efficiencies of Examples 7 to 14 are relatively high. 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, which makes the hole transport performance and the electron transport performance relatively high, and can increase the yield of excitons, so as to improve the efficiency of the first light-emitting device 101. Among them, 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%, indicating that the mass percentage of the first host material HP in the material of the light-emitting layer 131 is within a certain range, which can make the efficiency of the first light-emitting device 101 relatively high.

[0460] It can be seen from the above embodiments and comparative examples that the present disclosure can improve the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101) and alleviate the problem of efficiency roll-off under high current density by selecting the first host material HP from any one of the structures shown in general formula (IV). At the same time, the present disclosure can improve the thermal stability of the first host material HP and the second host material HN by setting the first host material HP and the second host material HN as deuterated materials, and can increase the device life of the light-emitting device 100 (for example, the first light-emitting device 101).

[0461] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be thought of by any person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A light emitting device, characterized in that: include: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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 4, characterized in that: 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 4, characterized in that: 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 4, characterized in that: 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 4, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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 claim 10 or 11, characterized in that: 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 claim 1 or 10, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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 claim 14, characterized in that: 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 claim 14, characterized in that: 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, characterized in that: include: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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 22, characterized in that: 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 22, characterized in that: 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 22, characterized in that: 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 22, characterized in that: 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 22, characterized in that: 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 22, characterized in that: 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 22, characterized in that: 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 22, characterized in that: 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, characterized in that: 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, characterized in that: 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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