Light-emitting substrate, display panel and display device

Abstract

The embodiment of the invention provides a light-emitting substrate, a display panel and a display device, relates to the technical field of display, and aims to solve the problem that the display device is green, red or yellow in low gray scale. The light-emitting substrate comprises a substrate and at least two light-emitting devices, the two light-emitting devices are arranged on the substrate and arranged in the first direction, and the first direction is parallel to the plane where the substrate is located; wherein the efficiency attenuation index of each of the at least two light emitting devices is less than or equal to 7%; the efficiency attenuation index refers to the absolute value of the difference value between the normalized current efficiency of the light-emitting device under the first preset current density and the normalized current efficiency of the light-emitting device under the second preset current density, and the absolute value of the difference value between the first preset current density and the second preset current density is larger than or equal to 14 mA / cm < 2 >. 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 substrate, a display panel and a display device. 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 substrate, a display panel and a display device, which are used to improve the problem of green, red or yellow color in low gray scale of the display device.

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

[0005] On the one hand, a light-emitting substrate is provided. The light-emitting substrate includes a substrate and at least two light-emitting devices; the two light-emitting devices are arranged on the substrate and arranged along a first direction, and the first direction is parallel to the plane where the substrate is located; wherein the efficiency decay index of each of the at least two light-emitting devices is less than or equal to 7%; the efficiency decay index refers to the absolute value of the difference between the normalized current efficiency of the light-emitting device at a first preset current density and the normalized current efficiency of the light-emitting device at a second preset current density, and the absolute value of the difference between the first preset current density and the second preset current density is greater than or equal to 14mA / cm 2 .

[0006] In the above-mentioned light-emitting substrate, the efficiency decay index of each of at least two light-emitting devices is less than or equal to 7%. On the one hand, the difference in current efficiency of the same light-emitting device at different brightness can be effectively reduced, so that the display difference of the same light-emitting device at different gray scales can be effectively reduced; on the other hand, when the efficiency decay index of each of at least two light-emitting devices in the above-mentioned light-emitting substrate is less than or equal to 7%, the absolute value of the difference between the efficiency decay indexes of any two of the at least two light-emitting devices is less than 7%, so that the current decay trends of different light-emitting devices tend to be consistent, and the consistency of the current efficiency of each light-emitting device is improved. In this way, the problem of greening, redding, or yellowing at low gray scales can be effectively alleviated, and the display effect can be effectively improved.

[0007] In some embodiments, an absolute value of a difference between efficiency decay indexes of any two light emitting devices among the at least two light emitting devices is less than or equal to 6%.

[0008] In some embodiments, at least two light-emitting devices include a first light-emitting device, a second light-emitting device, and a third light-emitting device arranged along a first direction; wherein the first light-emitting device is configured to emit red light; the second light-emitting device is configured to emit green light; the third light-emitting device is configured to emit blue light; the efficiency attenuation index of the second light-emitting device is less than or equal to the efficiency attenuation index of the first light-emitting device; the efficiency attenuation index of the third light-emitting device is less than or equal to the efficiency attenuation index of the first light-emitting device.

[0009] In some embodiments, an absolute value of a difference between the efficiency decay indexes of the second light emitting device and the third light emitting device is less than or equal to 3%.

[0010] In some embodiments, each of the at least two light-emitting devices includes: a first electrode and a second electrode arranged opposite to each other, and a light-emitting layer arranged between the first electrode and the second electrode; the material of the light-emitting layer of each of the at least two light-emitting devices includes a first main material and a light-emitting material; the material of the light-emitting layer of at least one of the at least two light-emitting devices also includes a second main material; the triplet energy level of the first main material is greater than the triplet energy level of the second main material; the triplet energy level of the second main material is greater than or equal to the triplet energy level of the light-emitting material.

[0011] In some embodiments, the difference between the triplet energy level of the first host material and the triplet energy level of the second host material is greater than or equal to 0.15 eV.

[0012] In some embodiments, the luminescent material is a fluorescent material, or a delayed fluorescent material.

[0013] In some embodiments, the mass ratio of the luminescent material in the luminescent layer is less than or equal to 5%.

[0014] In some embodiments, the hole mobility of the first host material is greater than or equal to the hole mobility of the second host material; and the electron mobility of the second host material is greater than or equal to the electron mobility of the first host material.

[0015] In some embodiments, a ratio of a hole mobility of the first host material to an electron mobility of the second host material is greater than or equal to 0.1.

[0016] In some embodiments, the hole mobility of the first host material is greater than or equal to 1×10 -6 cm 2 / Vs; and / or, the electron mobility of the second host material is greater than or equal to 1×10 -6 cm 2 / Vs.

[0017] In some embodiments, the first host material is selected from any one of the structures shown in the following general formula (I);

[0018]

[0019] Wherein, Ar1 is selected from a substituted or unsubstituted first group; Ar2 is selected from a substituted or unsubstituted second group; L is selected from any one of a single bond and a substituted or unsubstituted arylene group; m and n are the same or different and are independently selected from a positive integer greater than or equal to 1; the first group is selected from any one of the structures shown in the following general formula (IA).

[0020]

[0021] The second group is selected from any one of the structures represented by the following general formula (IB).

[0022]

[0023] Wherein, the value of p is selected from any one of 0, 1 and 2. Z and X are the same or different and are independently selected from O, S, N (R a ) and C(R b R c ) in any one of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R a , R b and R c are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, nitrile, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted haloalkoxy, substituted or unsubstituted aryl, substituted or unsubstituted haloaryl, substituted or unsubstituted silyl and substituted or unsubstituted heterocycle. 9 and R 10the same or different, and independently selected from any one of hydrogen, deuterium, halogen, amino, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted silanyl, substituted or unsubstituted germanyl, substituted or unsubstituted borane, substituted or unsubstituted selenanyl, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heteroalkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl.

[0024] In some embodiments, the first host material is selected from any one of the structures shown in the following general formula (IA).

[0025]

[0026] In some embodiments, the first host material is selected from any one of the structures represented by the following general formula (I-B1) and general formula (I-B2).

[0027]

[0028] In some embodiments, the first main material is selected from any one of the structures represented by the following general formula (I-C1), general formula (I-C2), general formula (I-C3), general formula (I-C4), general formula (I-C5), general formula (I-C6), general formula (I-C7) and general formula (I-C8).

[0029]

[0030] Among them, Z 1 and Z 2 The same or different, independently selected from O, S, N (R a ) and C(R b R c )

[0031] In some embodiments, the second group is selected from any one of the structures represented by the following formula (IB-1) and formula (IB-2).

[0032]

[0033] Wherein, Y is selected from O, S, N (R d )、C(R e R f )、Si(R g R h ) and Ge(R i Rj ) in any one of R d , R e , R f , R g , R h , R i and R j are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, nitrile, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted haloalkoxy, substituted or unsubstituted aryl, substituted or unsubstituted haloaryl, substituted or unsubstituted silyl and substituted or unsubstituted heterocycle.

[0034] In some embodiments, when the first host material is selected from any one of the structures shown in general formula (IA) and the second group is selected from any one of the structures shown in general formula (IB-1), X is selected from any one of O, S and C(RbRc).

[0035] In some embodiments, the mass percentage of the first host material in the light-emitting layer is greater than or equal to 40% and less than or equal to 90%.

[0036] In some embodiments, the second host material is selected from any one of the structures represented by the following general formula (II).

[0037]

[0038] Among them, X 1 and X 2 are the same or different, independently selected from N and C(R k ) in any one of R A , R B , R D and R E are the same or different, and are independently selected from a substituted or unsubstituted substituent group IIA, and a substituted or unsubstituted substituent group IIB, and in R A , R B , R D and R E There are at least two substituted or unsubstituted substituent groups IIA and at least one substituted or unsubstituted substituent group IIB. The substituent group IIA is selected from any one of IIA-a to IIA-i.

[0039]

[0040] The substituent group IIB is selected from any one of IIB-a to IIB-j.

[0041]

[0042]

[0043] Among them, Z 3 Selected from C(R m R n )、N(R p ), O and S. X 3 Any one selected from O and S. R k , R m , R n , R p , R 11 and R 12 are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, nitrile, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted haloalkoxy, substituted or unsubstituted aryl, substituted or unsubstituted haloaryl, substituted or unsubstituted silyl and substituted or unsubstituted heterocycle.

[0044] In some embodiments, the mass percentage of the second host material in the light-emitting layer is greater than or equal to 20% and less than or equal to 55%.

[0045] In some embodiments, the second host material is a phosphorescent material; and, the second host material is a tetradentate ligand material.

[0046] In some embodiments, the mass percentage of the second host material in the light-emitting layer is greater than or equal to 10% and less than or equal to 40%.

[0047] In some embodiments, when at least two light-emitting devices include a first light-emitting device, a second light-emitting device, and a third light-emitting device, the light-emitting layer of the first light-emitting device includes a first host material, a second host material, and a light-emitting material having a structure as shown in the following formula (RD).

[0048] and / or,

[0049] The light-emitting layer of the second light-emitting device includes a first host material, a second host material, and a light-emitting material having a structure as shown in the following formula (GD).

[0050]

[0051] On the other hand, a display panel is provided, comprising: a light-emitting substrate as described in any of the above embodiments and at least two pixel driving circuits, each of the at least two pixel driving circuits being electrically connected to a light-emitting device for driving the light-emitting device to emit light.

[0052] 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 substrate provided by the above technical solution, and will not be repeated here.

[0053] In another aspect, a display device is provided, comprising: a display panel as described in any of the above embodiments and a driving chip, wherein the driving chip is used to drive the display panel to display.

[0054] 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

[0055] 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.

[0056] Figure 1 is a structural diagram of a display device according to some embodiments;

[0057] Figure 2 is a structural diagram of a display panel according to some embodiments;

[0058] Figure 3 is a structural diagram of a light-emitting substrate according to some embodiments;

[0059] Figure 4 is a structural diagram of a light-emitting substrate according to some further embodiments;

[0060] Figure 5 is a structural diagram of a light-emitting substrate according to some other embodiments;

[0061] Figure 6 is a curve diagram showing a change in normalized current efficiency versus current density of a light emitting device according to some embodiments;

[0062] Figure 7 is a curve diagram showing a change in normalized current efficiency versus current density of a light emitting device according to some further embodiments;

[0063] Figure 8 is a curve diagram showing a change in normalized current efficiency versus current density of a light emitting device according to some further embodiments;

[0064] Fig. 9is a curve diagram showing a change in normalized current efficiency versus current density of a light emitting device according to some further embodiments;

[0065] Fig.10 is a curve diagram showing a change in normalized current efficiency versus current density of a light emitting device according to some further embodiments;

[0066] Fig.11 is a curve diagram showing a change in normalized current efficiency versus current density of a light emitting device according to some further embodiments;

[0067] Fig.12 is a curve diagram showing a change in normalized current efficiency versus current density of a light emitting device according to some other embodiments. DETAILED DESCRIPTION

[0068] 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.

[0069] 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.

[0070] 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.

[0071] “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.

[0072] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0073] 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).

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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 this 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.

[0078] like Figure 1 As shown, some embodiments of the present disclosure provide a display device 400 , which includes: a display panel 300 .

[0079] In some examples, the display device 400 may be, for example, an OLED (Organic Light Emitting Diode) display device 400 .

[0080] 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.

[0081] 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.

[0082] The display device 400 described above may be any display device 400 that displays either motion (e.g., video) or fixed (e.g., still image) and whether text or image. More specifically, it is expected that the display device 400 of the embodiment described may 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.

[0083] In some embodiments, Figure 2As 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 at least two light-emitting devices 100, and the at least two 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.

[0084] In some examples, such as Figure 2 As 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 at least two pixel driving circuits 311, wherein the pixel driving circuit 311 includes 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.

[0085] For example, Figure 2 As shown, at least two pixel driving circuits 311 and at least two light emitting devices 100 may be coupled one-to-one. In other examples, one pixel driving circuit 311 may be coupled to multiple light emitting devices 100 , or multiple pixel driving circuits 311 may be coupled to one light emitting device 100 .

[0086] 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.

[0087] 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 .

[0088] Exemplarily, the display panel 300 can be an OLED (Organic Light Emitting Diode) display panel 300. In this case, the encapsulation layer 320 covers the light-emitting device 100, encapsulating the light-emitting device 100 to prevent water vapor and oxygen in the external environment from entering the display panel 300 and damaging the organic material in the light-emitting device 100, thereby shortening the life of the OLED display panel 300.

[0089] In some embodiments, Figure 2 and Figure 3As 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. At least two light-emitting devices 100 can be disposed correspondingly to the plurality of openings Q one by one.

[0090] In some embodiments, Figure 3 to Figure 5 As shown, the at least two 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 the driving voltage, the first light emitting device 101 emits red light, the second light emitting device 102 emits green light, and the third light emitting device 103 emits blue light.

[0091] It should be noted that Figure 4-5 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 4-5 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 .

[0092] In some embodiments, each of the at least two light emitting devices 100 includes: a first electrode 110 and a second electrode 120 disposed opposite to each other, and a light emitting layer 130 disposed between the first electrode 110 and the second electrode 120. The first electrode 110 and the second electrode 120 are stacked along a second direction Y, and the second direction Y intersects with the first direction X.

[0093] For example, Figure 4-5 As shown, the second direction Y is arranged perpendicular to the first direction X. The first electrode 110 may be an anode, and the second electrode 120 may be a cathode. During operation, a voltage is applied to the first electrode 110 and the second electrode 120, 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 130, thereby emitting light.

[0094] Exemplarily, in order to ensure that the light-emitting device 100 can effectively emit light, the first electrode 110 (anode) is made of a material with a high work function, such as a material with a work function greater than 6 eV; the second electrode 120 (cathode) is 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 may 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 130 under the drive of the electric field, thereby compounding and emitting light.

[0095] In some examples, the light emitting device 100 is a bottom-emitting light emitting device 100, and the material of the first electrode 110 may be a transparent conductive metal oxide material to prevent the first electrode 110 from blocking light. For example, the material of the first electrode 110 may be indium tin oxide (ITO) or indium zinc oxide (IZO); the thickness of the first electrode 110 may be 80nm to 200nm. The average reflectivity of the material of the first electrode 110 in the visible light region may be 85% to 95%. The material of the second electrode 120 may be a metal material, for example, the material of the second electrode 120 may be magnesium, silver, aluminum, or a magnesium-silver alloy; when the material of the second electrode 120 is a magnesium-silver alloy, the mass ratio of magnesium to silver is 3:7 to 1:9; the process of forming the second electrode 120 is, for example, an evaporation process. The thickness of the second electrode 120 may be greater than or equal to 80nm to ensure good reflectivity.

[0096] In other examples, the light-emitting device 100 is a top-emitting light-emitting device 100, and the material of the first electrode 110 can be a composite layer structure composed of metal / conductive metal oxide, for example, the material of the first electrode 110 can be a composite layer structure of silver / indium tin oxide, a composite layer structure of silver / indium zinc oxide, wherein the thickness of the metal layer can be 80nm to 100nm, and the thickness of the conductive metal oxide is 5nm to 10nm. The average reflectivity of the material of the first electrode 110 in the visible light region can be 85% to 95%. The material of the second electrode 120 can be a metal material, for example, the material of the second electrode 120 can be magnesium, silver, aluminum, or magnesium-silver alloy; when the material of the second electrode 120 is a magnesium-silver alloy, the mass ratio of magnesium to silver is 3:7 to 1:9; the process of forming the second electrode 120 is, for example, an evaporation process. The thickness of the second electrode 120 can be 10nm to 20nm. The transmittance of the material of the second electrode 120 at 530nm is 50% to 60%.

[0097] In some embodiments, Figure 4-5As shown, in order to improve the luminous efficiency of the light-emitting device 100, at least one of a hole injection layer 140 (Hole Inject Layer, HIL), a hole transport layer 150 (Hole Transport Layer, HTL), and an electron blocking layer 160 (Electron Blocking Layer, EBL) is stacked between the first electrode 110 and the light-emitting layer 130; at least one of an electron injection layer 170 (Electron Inject Layer, EIL), an electron transport layer 180 (Electron Transport Layer, ETL), and a hole blocking layer 190 (Hole Blocking Layer, EBL) is stacked between the second electrode 120 and the light-emitting layer 130. By setting up the film layers such as the hole injection layer 140, the hole transport layer 150, the electron blocking layer 160, the electron injection layer 170, the electron transport layer 180, and the hole blocking layer 190, it is equivalent to setting up transition steps between the anode and the light-emitting layer 130 and between the cathode and the light-emitting layer 130, thereby reducing the barrier height that needs to be overcome for carrier transition, thereby making the light-emitting efficiency higher.

[0098] Exemplarily, the hole injection layer 140 is configured to reduce the hole injection barrier and improve the hole injection efficiency; the hole injection layer 140 can be a single-layer film formed by a single material, and the material of the hole injection layer 140 is, for example, 11-hexycyano-1 (HAT-CN) and phthalocyanine blue (CuPc); the hole injection layer 140 can also be prepared by P-type doping of the hole transport material, such as doping 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4TCNQ) in N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), or doping manganese trioxide (MnO) in 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC). 3 ); the doping concentration may be 0.5% to 10%. The thickness of the hole injection layer 140 may be 5nm to 20nm.

[0099] Exemplarily, the hole transport layer 150 is configured to transport holes, and the material of the hole transport layer 150 may be a material with high hole mobility, such as a carbazole material. The formation process of the hole transport layer 150 may be an evaporation process. The highest occupied orbital energy level (HOMO) of the hole transport layer 150 may be 5.2eV to 5.6eV. The thickness of the hole transport layer 150 may be 100nm to 140nm.

[0100] Exemplarily, the electron blocking layer 160 is configured to transfer holes and block electrons and excitons generated in the light emitting layer 130 ; the thickness of the electron blocking layer 160 may be 1 nm to 10 nm.

[0101] For example, the thickness of the electron injection layer 170 may be 0.5 nm to 2 nm.

[0102] For example, the thickness of the electron transport layer 180 may be 20 nm to 70 nm.

[0103] Exemplarily, the hole blocking layer 190 is configured to block holes and excitons generated in the light emitting layer 130 ; the thickness of the hole blocking layer 190 may be 2 nm to 10 nm.

[0104] In some embodiments, the second electrode 120 stacked with each light-emitting layer 130 is a structure that is connected to the entire layer, that is, the second electrode 120 can be a common electrode shared by multiple light-emitting devices 100. The hole injection layer 140 stacked with each light-emitting layer 130 can also be a structure that is connected to the entire layer, that is, the hole injection layer 140 can be a common film layer shared by multiple light-emitting devices 100. The hole transport layer 150, the electron blocking layer 160, the hole blocking layer 190, the electron injection layer 170, and the electron transport layer 180 can also be common film layers shared by multiple light-emitting devices 100.

[0105] Exemplarily, when the second electrode 120 is a common electrode shared by a plurality of light-emitting devices 100, the second electrode 120 is simultaneously formed on a side of the pixel defining layer 221 away from the substrate 210; when the hole injection layer 140 is a common film layer shared by a plurality of light-emitting devices 100, the hole injection layer 140 is simultaneously formed on a side of the pixel defining layer 221 away from the substrate 210. The description of when the hole transport layer 150, the electron blocking layer 160, the hole blocking layer 190, the electron injection layer 170, and the electron transport layer 180 are common film layers refers to the description of when the hole injection layer 140 is a common film layer, and will not be repeated here.

[0106] For example, Figure 5 As shown, the electron blocking layers 160 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 electron blocking layer 160 with matching performance can be selected as needed according to the different materials of the light-emitting layer 130 .

[0107] In some implementations, the OLED display device 400 may have a problem of greening, redding, or yellowing at low grayscales during use. This is because the display screen of the OLED display device 400 is a mixture of red (R), green (G), and blue (B), and the current efficiency attenuation (Roll-off) trends of the three colors red (R), green (G), and blue (B) at different grayscales are different. At low grayscales, the current efficiency of a portion of the light-emitting devices 100 (for example, the red light-emitting device 100 and the green light-emitting device 100) is relatively high, and the current efficiency of another portion of the light-emitting devices 100 (for example, the blue light-emitting device 100) is relatively low, resulting in the problem of greening, redding, or yellowing at low grayscales.

[0108] Based on this, Figure 3 to Figure 5 As shown, some embodiments of the present disclosure provide a light-emitting substrate 200, which includes at least two light-emitting devices 100, and the efficiency decay index ΔE of each of the at least two light-emitting devices 100 is less than or equal to 7%. The efficiency decay index ΔE refers to the efficiency decay index of the light-emitting device 100 at a first preset current density I 1 The normalized current efficiency E1′ under the second preset current density I 2 The absolute value of the difference between the normalized current efficiency E2′ under the first preset current density I 1 and the second preset current density I 2 The absolute value of the difference is greater than or equal to 14mA / cm 2 .

[0109] It should be noted that the light emitting device 100 has a first preset current density I 1 The normalized current efficiency E1′ under the first preset current density I 1 The ratio of the current efficiency E1 to the maximum current efficiency Max(E1,E2) under the condition is:

[0110]

[0111] The light emitting device 100 is charged at a second preset current density I 2 The normalized current efficiency E2′ under the second preset current density I 2 The ratio of the current efficiency E2 under the condition of , to the maximum current efficiency Max(E1,E2), that is:

[0112]

[0113] 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.

[0114] Exemplarily, the first preset current density I 1 The current density is 1 mA / cm 2 ; The second preset current density I 2 The current density is 15mA / cm 2 .

[0115] Exemplarily, the efficiency attenuation index ΔE can be calculated using the following formula.

[0116]

[0117] When the light-emitting substrate 200 includes a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103, the efficiency decay index ΔER of the first light-emitting device 101, the efficiency decay index ΔEG of the second light-emitting device 102, and the efficiency decay index ΔEB of the third light-emitting device 103 are respectively:

[0118]

[0119]

[0120]

[0121] Among them, ER1, EG1, and EB1 are respectively the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 101 at the first preset current density I 1 ER2, EG2, EB2 are the current efficiency of the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 at the second preset current density I 2Max(ER1, ER2) refers to the maximum of the corresponding current efficiencies when the current density of the first light-emitting device 101 is in the range of [I1, I2]; Max(EG1, EG2) refers to the maximum of the corresponding current efficiencies when the current density of the second light-emitting device 102 is in the range of [I1, I2]; Max(EB1, EB2) refers to the maximum of the corresponding current efficiencies when the current density of the third light-emitting device 103 is in the range of [I1, I2].

[0122] Exemplarily, when the light-emitting substrate 200 includes a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103, when the efficiency decay index ΔE of each of the at least two light-emitting devices 100 is less than or equal to 7%, at least the following three conditions are satisfied: (a): the efficiency decay index ΔER of the first light-emitting device 101 is less than or equal to 7%, that is, ΔER≤7%. (b): the efficiency decay index ΔEG of the second light-emitting device 102 is less than or equal to 7%, that is, ΔEG≤7%. (c): the efficiency decay index ΔEB of the third light-emitting device 103 is less than or equal to 7%, that is, ΔEB≤7%.

[0123] It can be understood that in the above-mentioned light-emitting substrate 200, the efficiency decay index of each light-emitting device 100 of at least two light-emitting devices 100 is less than or equal to 7%. On the one hand, the current efficiency difference of the same light-emitting device 100 (for example, the first light-emitting device 101, the second light-emitting device 102 or the third light-emitting device 103) at different brightness can be effectively reduced, so that the display difference of the same light-emitting device 100 at different grayscales can be effectively reduced; on the other hand, when the efficiency decay index of each light-emitting device 100 of at least two light-emitting devices 100 in the above-mentioned light-emitting substrate 200 is less than or equal to 7%, the absolute value of the difference between the efficiency decay indexes of any two light-emitting devices 100 of at least two light-emitting devices 100 is less than 7%, so that the current decay trends of different light-emitting devices 100 tend to be consistent, and the consistency of the current efficiency of each light-emitting device 100 is improved. In this way, the problem of greening, redding, or yellowing at low grayscale can be effectively alleviated, and the display effect can be effectively improved.

[0124] Exemplarily, the first preset current density I 1 and the second preset current density I 2 The absolute value of the difference can be 14mA / cm 2 , 15mA / cm 2 , 16mA / cm 2 or 18mA / cm 2 wait.

[0125] For example, the efficiency decay index ΔE of each of the at least two light emitting devices 100 may be 3%, 4%, 5%, 5.5%, 6%, 7%, or the like.

[0126] In some examples, the efficiency decay index ΔE of at least two of the first light emitting device 101 , the second light emitting device 102 , and the third light emitting device 103 is less than or equal to 5%.

[0127] In some embodiments, an absolute value of a difference between efficiency decay indexes ΔE of any two light emitting devices 100 of the at least two light emitting devices 100 is less than or equal to 6%.

[0128] Exemplarily, when the light-emitting substrate 200 includes a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103, when the absolute value of the difference between the efficiency decay index ΔE of any two light-emitting devices 100 of at least two light-emitting devices 100 is less than or equal to 6%, at least the following three conditions are satisfied:

[0129] (1) The absolute value of the difference between the efficiency decay index ΔER of the first light emitting device 101 and the efficiency decay index ΔEG of the second light emitting device 102 is less than or equal to 6%, that is, |ΔER-ΔEG|≤6%.

[0130] (2) The absolute value of the difference between the efficiency decay index ΔER of the first light emitting device 101 and the efficiency decay index ΔEB of the third light emitting device 103 is less than or equal to 6%, that is, |ΔER-ΔEB|≤6%.

[0131] (3) The absolute value of the difference between the efficiency decay index ΔEG of the second light emitting device 102 and the efficiency decay index ΔEB of the third light emitting device 103 is less than or equal to 6%, that is, |ΔEG-ΔEB|≤6%.

[0132] In some examples, at least one of the absolute value of the difference between the efficiency decay index ΔER of the first light-emitting device 101 and the efficiency decay index ΔEG of the second light-emitting device 102 |ΔER-ΔEG|, the absolute value of the difference between the efficiency decay index ΔER of the first light-emitting device 101 and the efficiency decay index ΔEB of the third light-emitting device 103 |ΔER-ΔEB|, and the absolute value of the difference between the efficiency decay index ΔEG of the second light-emitting device 102 and the efficiency decay index ΔEB of the third light-emitting device 103 |ΔEG-ΔEB| is less than 4%.

[0133] It can be understood that when the absolute value of the difference between the efficiency decay index ΔE of any two light-emitting devices 100 among at least two light-emitting devices 100 is less than or equal to 6%, the consistency of the current decay trend of different light-emitting devices 100 is improved, and the current efficiency of each light-emitting device 100 tends to be consistent. In this way, the problem of green, red, or yellow at low gray scale can be alleviated, and the display effect can be improved.

[0134] For example, the absolute value of the difference between the efficiency decay indexes ΔE of the two light emitting devices 100 may be 2%, 3%, 4%, 5%, 6%, or the like.

[0135] In other implementations, the luminescent material D of the first light-emitting device 101 and the luminescent material D of the second light-emitting device 102 are phosphorescent materials, and the luminescent material D of the third light-emitting device 103 is a fluorescent material. Since the phosphorescent material uses triplet excitons to emit light, triplet excitons have the characteristics of long life and are prone to quenching during the light-emitting process. As a result, the current efficiency varies greatly at different brightnesses, and the efficiency decay index ΔE is large, resulting in display differences at different grayscales, and at the same time causing differences between the efficiency decay index ΔEB of the third light-emitting device 103. For example, the efficiency decay index ΔEB of the third light-emitting device 103 is less than or equal to the efficiency decay index ΔER of the first light-emitting device 101; the efficiency decay index ΔEB of the third light-emitting device 103 is less than or equal to the efficiency decay index ΔEG of the second light-emitting device 102.

[0136] In some embodiments, the efficiency decay index ΔEG of the second light emitting device 102 is less than or equal to the efficiency decay index ΔER of the first light emitting device 101; the efficiency decay index ΔEB of the third light emitting device 103 is less than or equal to the efficiency decay index ΔER of the first light emitting device 101. That is, ΔEB≤ΔER, and ΔEG≤ΔER.

[0137] When ΔEB≤ΔER, and ΔEG≤ΔER, compared with the situation in the above implementation, the efficiency attenuation index ΔEG of the second light-emitting device 102 is relatively small, which can reduce the difference in current efficiency of the second light-emitting device 102 at different gray scales, so that the consistency of the current efficiency of the second light-emitting device 102 at different gray scales is improved, and the display difference of the second light-emitting device 102 at different gray scales is reduced, which can alleviate the problem of greening and yellowing at low gray scales, and the display effect can be improved.

[0138] In some examples, the efficiency decay index ΔEG of the second light emitting device 102 is less than the efficiency decay index ΔER of the first light emitting device 101; the efficiency decay index ΔEB of the third light emitting device 103 is less than the efficiency decay index ΔER of the first light emitting device 101. That is, ΔEB<ΔER, and ΔEG<ΔER.

[0139] In some embodiments, the absolute value of the difference between the efficiency decay index of the second light emitting device 102 and the third light emitting device 103 is less than or equal to 3%, that is, |ΔEG-ΔEB|≤3%.

[0140] When the absolute value of the difference between the efficiency decay index of the second light-emitting device 102 and the third light-emitting device 103 |ΔEG-ΔEB| is less than or equal to 3%, the absolute value of the difference between the efficiency decay index ΔEG of the second light-emitting device 102 and the efficiency decay index ΔEB of the third light-emitting device 103 can be controlled within 3%. In this way, the efficiency decay trend of the second light-emitting device 102 and the efficiency decay trend of the third light-emitting device 103 tend to be consistent, which can reduce the difference between the current efficiency of the second light-emitting device 102 and the current efficiency of the third light-emitting device 103 at different gray scales, alleviate the problem of greening and yellowing at low gray scales, and improve the display effect.

[0141] It should be noted that the relative magnitude relationship between the efficiency decay index ΔEB of the third light emitting device 103 and the efficiency decay index ΔEG of the second light emitting device 102 is not limited here. For example, the efficiency decay index ΔEB of the third light emitting device 103 is greater than the efficiency decay index ΔEG of the second light emitting device 102, in which case ΔEB-ΔEG<3%. Alternatively, the efficiency decay index ΔEG of the second light emitting device 102 is greater than the efficiency decay index ΔEB of the third light emitting device 103, in which case ΔEG-ΔEB<3%.

[0142] For example, the absolute value of the difference between the efficiency decay index ΔE of the second light emitting device 102 and the third light emitting device 103 may be 1%, 1.5%, 2%, 2.3% or 3%, etc.

[0143] In some embodiments, the material of the light-emitting layer 130 of each of the at least two light-emitting devices 100 includes a first host material H1 and a light-emitting material D; the material of the light-emitting layer 130 of at least one of the at least two light-emitting devices 100 further includes a second host material H2; the triplet energy level T1(H1) of the first host material H1 is greater than the triplet energy level T1(H2) of the second host material H2; the triplet energy level T1(H2) of the second host material H2 is greater than or equal to the triplet energy level T1(D) of the light-emitting material D, that is, T1(H1)>T1(H2)≥T1(D).

[0144] It can be understood that when T1(H1)>T1(H2)≥T1(D), during the light-emitting process of the light-emitting device 100, the direction of energy transfer can be: the first main material H1 transfers energy to the second main material H2, and the second main material H2 transfers energy to the light-emitting material D, which can improve the adequacy of energy transfer.

[0145] Exemplarily, the first host material H1 can be configured to: transport holes, and / or, transport energy to the second host material H2, and / or, transfer fluorescence resonance energy to the light-emitting material D.

[0146] Exemplarily, the second host material H2 may be configured to: transport electrons, and / or, to form excitons by combining electrons with holes, and to transfer fluorescence resonance energy to the light-emitting material D.

[0147] Exemplarily, the light-emitting material D may be configured to emit photons using energy obtained through fluorescence resonance energy transfer from the first host material H1 or the second host material H2, and / or to form excitons through the combination of electrons and holes.

[0148] Based on the above settings, on the one hand, by adding a second main material H2 to the material of the light-emitting layer 130 and setting the energy transmission direction, the energy transmission channel can be increased, so that the energy transmission is more sufficient during the light-emitting process of the light-emitting device 100, the energy utilization rate can be improved, and the light-emitting efficiency (such as current efficiency) of the light-emitting device 100 at different gray scales can be effectively improved. In this way, the efficiency decay index ΔE of the light-emitting device 100 can be reduced, and the display difference of the light-emitting device 100 at different gray scales can be effectively reduced; on the other hand, the light-emitting material D can receive the fluorescence resonance energy transfer of the second main material H2, reduce the probability of quenching of triplet excitons generated by the composite electrons and holes of the second main material H2, reduce the difference in the number of excitons at different gray scales, and reduce the efficiency decay index ΔE of the light-emitting device 100.

[0149] Exemplarily, the absolute value of the highest occupied molecular orbital energy level HOMO(H1) of the first host material H1 is greater than 5.7 eV and less than 6.55 eV. For example, the absolute value of the highest occupied molecular orbital energy level HOMO(H1) of the first host material H1 can be 5.8 eV, 5.9 eV, 6.0 eV, 6.2 eV or 6.5 eV, etc.

[0150] Exemplarily, the absolute value of the lowest unoccupied molecular orbital LOMO(H1) of the first host material H1 is greater than 2.2 eV and less than 3.2 eV. For example, the absolute value of the lowest unoccupied molecular orbital LOMO(H1) of the first host material H1 can be 2.21 eV, 2.23 eV, 2.25 eV, 2.28 eV or 2.29 eV, etc.

[0151] In some examples, the singlet energy level S1(H1) of the first host material H1 is greater than the singlet energy level S1(H2) of the second host material H2; the singlet energy level S1(H2) of the second host material H2 is greater than or equal to the singlet energy level S1(D) of the light-emitting material D, that is, S1(H1)>S1(H2)≥S1(D).

[0152] By such arrangement, the energy transmission direction during the light emission process of the light emitting device 100 can be further ensured. For example, the energy transmission direction is that the first host material H1 transmits energy to the second host material H2, and the second host material H2 transmits energy to the light emitting material D.

[0153] In some embodiments, the difference between the triplet energy level T1(H1) of the first host material H1 and the triplet energy level T1(H2) of the second host material H2 is greater than or equal to 0.15 eV, that is, T1(H1)-T1(H2)≥0.15 eV.

[0154] It can be understood that by increasing the difference between the triplet energy level T1 (H1) of the first host material H1 and the triplet energy level T1 (H2) of the second host material H2, the energy difference (GAP) between the triplet energy level T1 (H1) of the first host material H1 and the triplet energy level T1 (H2) of the second host material H2 can be increased. In this way, it can be ensured that energy is transmitted in a set direction, that is, the first host material H1 can transmit energy to the second host material H2, but the second host material H2 will not transmit energy to the first host material H1.

[0155] For example, the difference between the triplet energy level T1(H1) of the first host material H1 and the triplet energy level T1(H2) of the second host material H2 may be 0.15 eV, 0.20 eV, 0.25 eV or 0.30 eV, etc.

[0156] In some embodiments, the light emitting layer 130 of at least one of the at least two light emitting devices 100 emits light with a half-peak width of a spectrum that is less than or equal to 35 nm.

[0157] In the related art, when the half-peak width of the emission spectrum of the light-emitting layer 130 is less than or equal to 35 nm, the light emitted by the light-emitting layer 130 is fluorescence, and the light-emitting material D in the light-emitting layer 130 that emits light is a fluorescent material or a delayed fluorescent material, not a phosphorescent material.

[0158] It is understandable that since phosphorescent materials use triplet excitons to emit light, triplet excitons have the characteristic of long life, which makes triplet excitons prone to quenching during the light-emitting process, resulting in differences in the number of excitons at different grayscales, leading to an increase in the efficiency decay index ΔE of the light-emitting device 100. When the half-peak width of the spectrum of light emitted by the light-emitting layer 130 of at least one of the at least two light-emitting devices 100 is less than or equal to 35nm, the light-emitting material D of the light-emitting layer 130 of at least one light-emitting device 100 is a fluorescent material or a delayed fluorescent material, not a phosphorescent material, so that the problem of triplet excitons being prone to quenching can be avoided, and the efficiency decay index ΔE of the light-emitting device 100 can be reduced.

[0159] Exemplarily, in the case where at least two light-emitting devices 100 include a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103, for one of the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103, the half-peak width of the spectrum of light emitted by the light-emitting layer 130 is less than or equal to 35 nm; or, for two of the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103, the half-peak width of the spectrum of light emitted by the light-emitting layer 130 is less than or equal to 35 nm.

[0160] In some embodiments, the luminescent material D is a fluorescent material or a delayed fluorescent material. That is, the luminescent material D of each of the at least two light-emitting devices 100 is a fluorescent material or a delayed fluorescent material, but not a phosphorescent material.

[0161] As mentioned above, the triplet excitons of the phosphorescent material are prone to quenching during the light emission process, resulting in differences in the number of excitons at different grayscales, which leads to an increase in the efficiency decay index ΔE of the light emitting device 100. When the light emitting material D is a fluorescent material or a delayed fluorescent material, and is not a phosphorescent material, the light emitted by the light emitting layer 130 of each of the at least two light emitting devices 100 is fluorescent light, which can avoid the problem of triplet excitons being prone to quenching, and can reduce the efficiency decay index ΔE of each light emitting device 100.

[0162] In some embodiments, the mass ratio of the light-emitting material D in the light-emitting layer 130 is less than or equal to 5%.

[0163] It is understandable that the photons emitted by the luminescent material D include: photons emitted by energy obtained through fluorescence resonance energy transfer of the first host material H1 and / or the second host material H2, and photons emitted by excitons formed by composite electrons and holes. When the mass proportion of the luminescent material D in the luminescent layer 130 is greater than 5%, the proportion of photons emitted by the luminescent material D through excitons formed by its own composite electrons and holes in the photons emitted by the luminescent material D increases, affecting the luminous efficiency and efficiency attenuation index ΔE of the light-emitting device 100. The following is an introduction based on the two cases where the luminescent material D is a fluorescent material or a delayed fluorescent material.

[0164] When the luminescent material D is a fluorescent material, the singlet exciton is used for luminescence, and the energy utilization rate is relatively low, and the luminous efficiency is relatively low. When the proportion of photons emitted by the luminescent material D (fluorescent material) through the excitons formed by the self-combined electrons and holes in the photons emitted by the luminescent material D increases, the energy utilization rate of the light-emitting device 100 will be reduced, and the luminous efficiency of the light-emitting device 100 will be reduced. Therefore, by setting the mass proportion of the luminescent material D in the light-emitting layer 130 to be less than or equal to 5%, the energy utilization rate of the light-emitting device 100 can be improved, and the luminous efficiency of the light-emitting device 100 can be improved.

[0165] When the luminescent material D is a delayed fluorescent material, triplet excitons are used for luminescence. The triplet excitons have the characteristic of long life, which makes the triplet excitons easy to quench during the luminescence process, resulting in the difference in the number of excitons under different grayscales, leading to an increase in the efficiency decay index of the light-emitting device 100. When the proportion of photons emitted by the excitons formed by the self-combined electrons and holes of the luminescent material D (delayed fluorescent material) in the photons emitted by the luminescent material D increases, the generated triplet excitons are easy to quench, resulting in the loss of excitons, reducing the luminescence efficiency, and at the same time leading to an increase in the efficiency decay index ΔE of the light-emitting device 100. Therefore, by setting the mass proportion of the luminescent material D in the luminescent layer 130 to be less than or equal to 5%, the efficiency decay index ΔE of the light-emitting device 100 can be made relatively high.

[0166] For example, the mass percentage of the light-emitting material D in the light-emitting layer 130 may be 0.5%, 1.0%, 1.5%, 2.0%, 3.0%, 4.0% or 5.0%, etc.

[0167] In some embodiments, the hole mobility of the first host material H1 is greater than or equal to the hole mobility of the second host material H2; and the electron mobility of the second host material H2 is greater than or equal to the electron mobility of the first host material H1.

[0168] It can be understood that when the hole mobility of the first host material H1 is greater than the electron mobility of the first host material H1, the first host material H1 is a hole-biased material and can be configured to transport holes; when the electron mobility of the second host material H2 is greater than the hole mobility of the second host material H2, the second host material H2 is an electron-biased material and can be configured to transport electrons. In this way, when the first host material H1 and the second host material H2 are used together, the transmission efficiency of holes and electrons can be increased, the yield of excitons can be increased, and the luminous efficiency can be improved.

[0169] In some embodiments, a ratio of a hole mobility of the first host material H1 to an electron mobility of the second host material H2 is greater than or equal to 0.1.

[0170] By setting the ratio of the hole mobility of the first main material H1 to the electron mobility of the second main material H2 to be greater than or equal to 0.1, the number of electrons and the number of holes are balanced, and the number of electrons and the number of holes are closer to 1:1, which is conducive to the recombination and formation of excitons on the second main material H2.

[0171] It should be noted that the ratio of the hole mobility of the first host material H1 to the electron mobility of the second host material H2 is greater than or equal to 0.1, including the following two situations.

[0172] The first case: the hole mobility of the first host material H1 is greater than or equal to the electron mobility of the second host material H2; that is, the ratio of the hole mobility of the first host material H1 to the electron mobility of the second host material H2 is greater than or equal to 1.

[0173] The second case: the hole mobility of the first host material H1 is less than the electron mobility of the second host material H2; and the ratio of the hole mobility of the first host material H1 to the electron mobility of the second host material H2 is greater than or equal to 0.1 and less than 1.

[0174] For example, the ratio of the hole mobility of the first host material H1 to the electron mobility of the second host material H2 may be 0.1, 0.2, 0.5, 1, 2, 3 or 5, etc.

[0175] In some embodiments, the hole mobility of the first host material H1 is greater than or equal to 1×10 -6 cm 2 / Vs; and /

[0176] Or, the electron mobility of the second host material H2 is greater than or equal to 1×10 -6 cm 2 / Vs.

[0177] When the hole mobility of the first host material H1 is greater than or equal to 1×10 -6 cm 2 / Vs, the hole mobility of the first host material H1 is relatively high, and faster hole transport can be achieved. When the electron mobility of the second host material H2 is greater than or equal to 1×10 -6 cm 2 / Vs, the electron mobility of the second main material H2 is relatively high, and faster electron transmission can be achieved. Through the above settings, the transmission efficiency of electrons and holes can be increased, and the exciton yield of the second main material H2 can be increased. In this way, the luminous efficiency of the light-emitting device 100 can be improved, the efficiency attenuation of the light-emitting device 100 can be reduced, the efficiency attenuation index ΔE of the light-emitting device 100 can be effectively reduced, and the display difference of the light-emitting device 100 under different grayscales can be effectively reduced.

[0178] For example, the hole mobility of the first host material H1 is greater than or equal to 1×10 -5 cm 2 / Vs; and / or, the electron mobility of the second host material H2 is greater than or equal to 1×10 -5 cm 2 / Vs.

[0179] For example, the hole mobility of the first host material H1 may be 1×10 -6 cm 2 / Vs,5×10 -6 cm 2 / Vs,1×10 - 5 cm 2 / Vs,3×10 -5 cm 2 / Vs,5×10 -5 cm 2 / Vs or 1×10 -4 cm 2 / Vs, etc.

[0180] For example, the electron mobility of the second host material H2 may be 1×10 -6 cm 2 / Vs,5×10 -6 cm 2 / Vs,1×10 - 5 cm 2 / Vs,3×10 -5 cm 2 / Vs,5×10 -5 cm 2 / Vs or 1×10 -4 cm 2 / Vs, etc.

[0181] In some embodiments, the first host material H1 is selected from any one of the structures shown in the following general formula (I);

[0182]

[0183] Wherein, Ar1 is selected from a substituted or unsubstituted first group.

[0184] Ar2 is selected from a substituted or unsubstituted second group.

[0185] L is selected from any one of a single bond and a substituted or unsubstituted arylene group.

[0186] m and n are the same or different and are independently selected from positive integers greater than or equal to 1.

[0187] The first group is selected from any one of the structures represented by the following general formula (IA).

[0188]

[0189] The second group is selected from any one of the structures represented by the following general formula (IB).

[0190]

[0191] The value of p is selected from any one of 0, 1 and 2.

[0192] Z and X are the same or different and are independently selected from O, S, N (R a ) and C(R b R c )

[0193] R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R a , R b and R c are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, nitrile, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted haloalkoxy, substituted or unsubstituted aryl, substituted or unsubstituted haloaryl, substituted or unsubstituted silyl and substituted or unsubstituted heterocycle.

[0194] R 9 , R 10the same or different, and independently selected from any one of hydrogen, deuterium, halogen, amino, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted silanyl, substituted or unsubstituted germanyl, substituted or unsubstituted borane, substituted or unsubstituted selenanyl, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heteroalkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl.

[0195] It should be noted that, in the general formula (I), The connection relationship between Ar1 and the carbazole group shown in the general formula (I) refers to the fusion of Ar1 and the six-membered ring in the carbazole group. When Ar1 and the six-membered ring in the carbazole group are fused, the position of the carbon atom shared by Ar1 and the carbazole group is not limited. For example, Ar1 and the carbazole group can share carbon atoms No. 2 and No. 3, or carbon atoms No. 3 and No. 4, or carbon atoms No. 4 and No. 5.

[0196] In the above general formula (I), L can be a single bond. When L is a single bond, the nitrogen in the carbazole group and Ar2 are directly connected by a covalent bond. Moreover, L can be a substituted or unsubstituted arylene group. The structure of the arylene group is introduced below by taking phenylene as an example. Phenyl refers to the general term for the remaining groups after the hydrogen atom of a carbon atom on the benzene ring is removed. Phenylene refers to the general term for the remaining groups after the hydrogen atoms on two carbon atoms on the benzene ring are removed. For the understanding of arylene groups, reference can be made to the above content, which will not be repeated here. Exemplarily, the arylene group can be a phenylene group, or a biphenylene group, etc. When the arylene group is selected from a substituted arylene group, there is no limitation on the type and number of substituents.

[0197] In the above general formula (I), m and n are the same or different and are independently selected from positive integers greater than or equal to 1; including at least the following four cases:

[0198] The first case: m=n=1, that is, the general formula (I) contains a carbazole group and an Ar2, and a carbazole group and an Ar2 are connected by L. In this case, L can be a single bond or a substituted or unsubstituted arylene group.

[0199] The second case: m=1 and n>1, that is, the general formula (I) contains one carbazole group and at least two Ar2, and one carbazole group and at least two Ar2 are connected by L. In this case, L is a substituted or unsubstituted arylene group.

[0200] The third case: m>1 and n=1, that is, the general formula (I) contains at least two carbazolyl groups and one Ar2, and at least two carbazolyl groups and one Ar2 are connected by L. In this case, L is a substituted or unsubstituted arylene group.

[0201] The fourth case: m>1 and n>1, that is, the general formula (I) contains at least two carbazolyl groups and at least two Ar2, and at least two carbazolyl groups and at least two Ar2 are connected by L. In this case, L is a substituted or unsubstituted arylene group.

[0202] It should be noted that in the general formula (I), the connection position between L and Ar2 is not limited. That is, L can be connected to R in the structure shown in the general formula (IB). 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and any one of X.

[0203] In the above general formula (IA), the value of p is selected from any one of 0, 1 and 2. When p is 2, the two

[0204] can both be fused with carbazole groups; or, After thickening, one of When p is 0, the structure shown in the general formula (I) is as follows, which will not be described in detail here.

[0205] In the above general formula (IA) and general formula (IB), Z and X are the same or different and are independently selected from O, S, N (R a ) and CR b R c ) in which O is oxygen; S is sulfur; N(R a ) is substituted or unsubstituted nitrogen; C(R b R c ) is a substituted or unsubstituted carbon.

[0206] When R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R a , R b and Rc When R is selected from any one of substituted alkyl, substituted haloalkyl, substituted alkoxy, substituted haloalkoxy, substituted aryl, substituted haloaryl, substituted silyl and substituted heterocycle, and / or when R 9 and R 10 When the group is selected from substituted alkyl, substituted cycloalkyl, substituted heteroalkyl, substituted heterocycloalkyl, substituted aralkyl, substituted alkoxy, substituted aryloxy, substituted silanyl, substituted germyl, substituted boryl, substituted selenoyl, substituted alkenyl, substituted cycloalkenyl, substituted heteroalkenyl, substituted alkynyl, substituted aryl and substituted heteroaryl, there is no limitation on the type of the substituent.

[0207] It can be understood that when the triplet energy level T1 of the first host material H1 is low, during the light emitting process of the light emitting device 100, the triplet excitons generated on the second host material H2 will leak to the first host material H1, making the efficiency of the light emitting device 100 low, and at the second preset current density I 2 Under this condition, the leakage of the triplet excitons will be relatively more. The structure shown in the general formula (I) contains a carbazole group and a hole-type group fused with carbazole. First, the hole mobility of the first host material can be improved, and the hole transport effect can be enhanced. Second, the first host material H1 can have a relatively high triplet energy level T1. In this way, the excitons generated on the second host material H2 can be prevented from leaking to the first host material H1, causing the efficiency of the light-emitting device 100 to decrease. In addition, the first host material H1 selected from the structure shown in the general formula (I) has a relatively high molecular weight, which can increase the glass transition temperature Tg of the first host material and improve the stability of the first host material. At the same time, the first host material H1 selected from the structure shown in the general formula (I) can be compatible with the preparation process of the light-emitting device 100 in the related technology, such as the evaporation process, which reduces the manufacturing cost of the light-emitting device 100.

[0208] An exemplary structure of the first host material H1 having a structure represented by the general formula (I) is described below.

[0209] In some examples, when m=n=1, L is a phenylene group, p=1, Ar1 and the carbazole group share carbon atoms 2 and 3, Z is nitrogen, and X is oxygen, the structural formula of the first host material H1 can be as shown below.

[0210]

[0211] In some examples, when m=n=1, L is a phenylene group, p=2, Ar1 and the carbazole group share carbon atoms 2 and 3, and X is nitrogen, the structural formula of the first host material H1 can be as shown below.

[0212]

[0213] It should be noted that the above-listed structural formulas are examples of the structure of the first host material H1, and are not limitations on the first host material H1. Moreover, (H1-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.

[0214] In some embodiments, the first host material H1 is selected from any one of the structures shown in the following general formula (IA);

[0215]

[0216] It should be noted that the description of Ar2 here can refer to the above description of Ar2; the description of L here can refer to the above description of L; the description of m and n here can refer to the above description of m and n, and no further details will be given here.

[0217] It can be understood that when p in the general formula (IA) is 0, the structure represented by the general formula (I) can be transformed into the structure represented by the general formula (IA).

[0218] An exemplary structure of the first host material H1 having a structure represented by the general formula (IA) is described below.

[0219] In some examples, when m=n=1, L is a phenylene group or a biphenylene group, and X is oxygen, the structural formula of the first host material H1 may be as shown below.

[0220]

[0221] In some examples, when m=n=1, L is phenylene, and X is sulfur, the structural formula of the first host material H1 can be as shown below.

[0222]

[0223] In some examples, when m=n=1, L is a phenylene group or a biphenylene group, and X is nitrogen, the structural formula of the first host material H1 may be as shown below.

[0224]

[0225] In some examples, when m=n=1, L is a phenylene group, and X is a substituted carbon, the structural formula of the first host material H1 can be as shown below.

[0226]

[0227] It should be noted that the above-listed structural formulas are examples of the structure of the first host material H1, and are not limitations on the first host material H1. Moreover, (H1-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.

[0228] In some embodiments, the first host material H1 is selected from any one of the structures represented by the following general formula (I-B1) and general formula (I-B2).

[0229]

[0230] It should be noted that the description of Ar2 here can refer to the above description of Ar2; the description of L here can refer to the above description of L; the description of Z here can refer to the above description of Z; the description of m and n here can refer to the above description of m and n, and no further details will be given here.

[0231] It can be understood that when p in the general formula (IA) is 1, and Ar1 shares carbon atoms 3 and 4 when fused with the carbazole group, the structure shown in the general formula (I) can be transformed into the structure shown in the general formula (I-B1) or the general formula (I-B2).

[0232] An exemplary structure of the first host material H1 having a structure represented by the general formula (I-B1) is described below.

[0233] In some examples, when m=n=1, L is phenylene, X is oxygen, and Z is oxygen or sulfur, the structural formula of the first host material H1 may be as shown below.

[0234]

[0235] An exemplary structure of the first host material H1 having a structure represented by the general formula (I-B2) is described below.

[0236] In some examples, when m=n=1, L is phenylene, X is oxygen, and Z is oxygen, the structural formula of the first host material H1 can be as shown below.

[0237]

[0238] In some examples, when m=n=1, L is phenylene, X is sulfur, and Z is oxygen, the structural formula of the first host material H1 can be as shown below.

[0239]

[0240] In some examples, when m=n=1, L is a phenylene group or a biphenylene group, X is nitrogen, and Z is oxygen or sulfur, the structural formula of the first host material H1 may be as shown below.

[0241]

[0242] It should be noted that the above-listed structural formulas are examples of the structure of the first host material H1, and are not limitations on the first host material H1. Moreover, (H1-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.

[0243] In some embodiments, the first main material H1 is selected from any one of the structures represented by the following general formula (I-C1), general formula (I-C2), general formula (I-C3), general formula (I-C4), general formula (I-C5), general formula (I-C6), general formula (I-C7) and general formula (I-C8).

[0244]

[0245] Among them, Z 1 and Z 2 The same or different, independently selected from O, S, N (R a ) and C(R b R c ) in which O is oxygen; S is sulfur; N(R a ) is substituted or unsubstituted nitrogen; C(R b R c ) is a substituted or unsubstituted carbon.

[0246] It should be noted that the description of Ar2 here can refer to the above description of Ar2; the description of L here can refer to the above description of L; the description of m and n here can refer to the above description of m and n, and no further details will be given here.

[0247] It is understood that when p in the general formula (IA) is 2, the two After thickening, one of When Ar1 is fused with a carbazole group and carbon atoms 3 and 4 are shared when Ar1 is fused with a carbazole group, the structure represented by the general formula (I) can be transformed into the structure represented by the general formula (I-C1), the general formula (I-C2), the general formula (I-C3), the general formula (I-C4), the general formula (I-C5), the general formula (I-C6), the general formula (I-C7) or the general formula (I-C8).

[0248] In some embodiments, the second group is selected from any one of the structures represented by the following formula (IB-1) and formula (IB-2).

[0249]

[0250] Wherein, Y is selected from O, S, N (R d )、C(Re R f )、Si(R g R h ) and Ge(R i R j ) in which O is oxygen; S is sulfur; N(R d ) is substituted or unsubstituted nitrogen; C(R e R f ) is substituted or unsubstituted carbon; Si(R g R h ) is substituted or unsubstituted silicon; Ge(R i R j ) is substituted or unsubstituted germanium.

[0251] R d , R e , R f , R g , R h , R i and R j are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, nitrile, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted haloalkoxy, substituted or unsubstituted aryl, substituted or unsubstituted haloaryl, substituted or unsubstituted silyl and substituted or unsubstituted heterocycle.

[0252] It should be noted that when R d , R e , R f , R g , R h , R i and R j When any one is selected from a substituted alkyl group, a substituted halogenated alkyl group, a substituted alkoxy group, a substituted halogenated alkoxy group, a substituted aryl group, a substituted halogenated aryl group, a substituted silyl group and a substituted heterocycle, the type of the substituent is not limited herein.

[0253] As can be seen from the above, the second group is selected from any one of the following structures (IB). 9 , R 10 When condensed with carbon atoms 1', 6', 7', 12' and X to form a ring, the structure represented by the general formula (IB) can be transformed into the structure represented by the general formula (IB-1) or the general formula (IB-2). 9 , R 10 Direct condensation to a single bond; general formula (IB-2) corresponds to R 9 , R 10 Condensed to the case of Y.

[0254]

[0255] The following describes an exemplary structure of the first host material H1 when the second group is selected from the structure represented by the general formula (IB-1).

[0256] In some examples, when X is oxygen, the structural formula of the first host material H1 can be as shown above (H1-1), (H1-4), (H1-5), (H1-10), (H1-11), and (H1-12).

[0257] In some examples, when X is sulfur, the structural formula of the first host material H1 can be as shown in (H1-6) and (H1-13) above.

[0258] In some examples, when X is nitrogen, the structural formula of the first host material H1 can be as shown in (H1-2), (H1-3), (H1-14), (H1-15), and (H1-16) above.

[0259] In some examples, when X is substituted carbon, the structural formula of the first host material H1 can be as shown in (H1-9) above.

[0260] The following describes an exemplary structure of the first host material H1 when the second group is selected from the structure represented by the general formula (IB-2).

[0261] In some examples, when X is nitrogen and Y is substituted carbon, the structural formula of the first host material H1 can be as shown in (H1-7) above.

[0262] In some embodiments, when the first host material H1 is selected from any one of the structures shown in the general formula (IA), and the second group is selected from any one of the structures shown in the general formula (IB-1), X is selected from O, S and C (R b R c )

[0263] It is understood that when X is selected from O, S and C (R b R c), X is not substituted or unsubstituted nitrogen. That is to say, when the first host material H1 is selected from any one of the structures shown in the general formula (IA), the second group is selected from any one of the structures shown in the general formula (IB-1), and X is not substituted or unsubstituted nitrogen, Ar2 is not a carbazole group. This is because when the first host material H1 is selected from any one of the structures shown in the general formula (IA), and Ar2 is a carbazole group, the structure of the first host material H1 carries two carbazole groups, which will make the hole mobility of the first host material H1 higher, resulting in an increase in the imbalance of holes and electrons in the light-emitting layer 130, shrinking the exciton recombination area on the interface, resulting in an increase in the exciton concentration, an increase in quenching, and a relatively poor device life. Therefore, when the first host material H1 is selected from any one of the structures shown in the general formula (IA) and the second group is selected from any one of the structures shown in the general formula (IB-1), and X is not set to be substituted or unsubstituted nitrogen, the hole mobility of the first host material H1 can be within an appropriate range, the balance of holes and electrons in the light-emitting layer 130 can be increased, and the device life of the light-emitting device 100 can be increased.

[0264] In some embodiments, the mass proportion of the first host material H1 in the light-emitting layer 130 is greater than or equal to 40% and less than or equal to 90%. For example, the mass proportion of the first host material H1 in the light-emitting layer 130 may be 40%, 50%, 60%, 75%, 80% or 90%.

[0265] It can be understood that when the mass proportion of the first host material H1 in the light-emitting layer 130 is less than 40%, the hole transfer efficiency is relatively low, and the exciton yield is relatively low during the light-emitting process of the light-emitting device 100, resulting in a decrease in the light-emitting efficiency of the light-emitting device 100. When the mass proportion of the first host material H1 in the light-emitting layer 130 is greater than 90%, the mass proportion of the second host material H2 in the light-emitting layer 130, and / or the mass proportion of the light-emitting material D in the light-emitting layer 130, is relatively low. Among them, when the mass proportion of the second host material H2 in the light-emitting layer 130 is relatively low, the energy transfer function from the second host material H2 to the light-emitting material D cannot meet the requirements, and the efficiency attenuation index ΔE of the light-emitting device 100 is relatively high. When the mass proportion of the luminescent material D in the luminescent layer 130 is relatively low, on the one hand, the luminescent material D that can receive energy during the fluorescence resonance energy transfer of the first host material H1 and / or the second host material H2 is too small, so that the luminescence efficiency of the luminescent material D is relatively low; on the other hand, the number of photons emitted by the first host material H1 and / or the second host material H2 increases, and the wavelength of the light emitted by the first host material H1 and / or the second host material H2 is inconsistent with the wavelength of the target emission light of the light-emitting device 100, which cannot meet the luminescence requirements of the light-emitting device 100; at the same time, the photons emitted by the first host material H1 and / or the second host material H2 are prone to quenching, resulting in a decrease in the overall luminescence efficiency of the light-emitting device 100. Therefore, by setting the mass proportion of the first host material H1 in the luminescent layer 130 to be greater than or equal to 40% and less than or equal to 90%, the hole transmission efficiency of the light-emitting device 100 can be relatively high, the luminescence efficiency can be improved, and the light emitted by the luminescent layer 130 can meet the luminescence requirements of the light-emitting device 100.

[0266] The above is an exemplary description of the first main material H1, and the following is an exemplary introduction of the second main material H2.

[0267] In some embodiments, the second host material H2 is selected from any one of the structures represented by the following general formula (II).

[0268]

[0269] Among them, X 1 and X 2 are the same or different, independently selected from N and C(R k ) wherein N is nitrogen; C(R k ) is a substituted or unsubstituted carbon.

[0270] R A , R B , R D and R Eare the same or different, and are independently selected from a substituted or unsubstituted substituent group IIA, and a substituted or unsubstituted substituent group IIB, and in R A , R B , R D and R E There are at least two substituted or unsubstituted substituent groups IIA and at least one substituted or unsubstituted substituent group IIB. The substituent group IIA is selected from any one of IIA-a to IIA-i.

[0271]

[0272] The substituent group IIB is selected from any one of IIB-a to IIB-j.

[0273]

[0274]

[0275] Among them, Z 3 Selected from C(R m R n )、N(R p ), O and S. Wherein, O is oxygen; S is sulfur; N (R p ) is substituted or unsubstituted nitrogen; C(R m R n ) is a substituted or unsubstituted carbon.

[0276] X 3 Any one selected from O and S. Wherein, O is oxygen; S is sulfur.

[0277] R k , R m , R n , R p , R 11 and R 12 are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, nitrile, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted haloalkoxy, substituted or unsubstituted aryl, substituted or unsubstituted haloaryl, substituted or unsubstituted silyl and substituted or unsubstituted heterocycle.

[0278] When R k , R m , R n , R p , R 11 and R 12When R is selected from any one of substituted alkyl, substituted haloalkyl, substituted alkoxy, substituted haloalkoxy, substituted aryl, substituted haloaryl, substituted silyl and substituted heterocycle, and / or A , R B , R D and R E When the substituent is selected from one of a substituted substituent group IIA and a substituted substituent group IIB, the type of the substituent is not limited herein.

[0279] It should be noted that the two benzene rings in IIA-a can be connected by a single bond to form a substituted or unsubstituted IIA-a-1, whose structural formula can be as shown below.

[0280]

[0281] It should be noted that the above-listed structural formulas are examples of the structures of substituent group IIA and substituent group IIB, and are not limitations on the structures of substituent group IIA and substituent group IIB. (IIA-x) and (IIB-x) in the above structural formulas are aliases for each structural formula, and are not part of the structural formula.

[0282] Based on the structure shown in the general formula (II), the second host material H2 is a delayed fluorescent material. On the one hand, the delayed fluorescent material has a high internal quantum efficiency, can compound holes and electrons to generate relatively more excitons, and can improve the luminous efficiency of the light-emitting device 100; on the other hand, using the delayed fluorescent material as the second host material H2, energy can be transferred to the light-emitting material D (for example, a fluorescent material that emits red light, or a fluorescent material that emits red light) through fluorescence resonance energy transfer, thereby improving energy utilization and luminous efficiency. At the same time, the light-emitting material D can reduce the probability of quenching of triplet excitons generated by the compound electrons and holes of the second host material H2, and can reduce the difference in the number of excitons under different grayscales, and reduce the efficiency attenuation index ΔE of the light-emitting device 100. In addition, the second host material H2 selected from the structure shown in the general formula (II) can be compatible with the preparation process of the light-emitting device 100 in the related art, such as the evaporation process, thereby reducing the manufacturing cost of the light-emitting device 100.

[0283] An exemplary structure of the second host material H2 having a structure represented by the general formula (II) is described below.

[0284] For example, when X1 and X2 are substituted or unsubstituted carbon, R A , R B , R D and R E When at least two of them are IIA-a-1 and at least one is IIB-j, the structural formula of the second host material H2 can be as shown below.

[0285]

[0286]

[0287] For example, when X1 and X2 are substituted or unsubstituted carbon, R A , R B , R D and R E When they are IIA-a-1, IIA-i, IIA-h, and IIB-j respectively, the structural formula of the second main material H2 can be as shown below.

[0288]

[0289] For example, when X1 and X2 are substituted or unsubstituted carbon, R A , R B , R D and R E When three of them are substituted IIA-a-1 and one is IIB-j, the structural formula of the second host material H2 can be as shown below.

[0290]

[0291] It should be noted that the above-listed structural formula is an example of the structure of the second main material H2, and is not a limitation on the structure of the second main material H2. (H2-x) in the above structural formula is a synonym for each structural formula, and is not a part of the structural formula. Wherein, x is a positive integer, and the same applies to the following.

[0292] In some embodiments, the mass proportion of the second host material H2 in the light-emitting layer 130 is greater than or equal to 20% and less than or equal to 55%.

[0293] 25%, 30%, 40%, 50% or 55% etc.

[0294] It is understandable that when the mass proportion of the second host material H2 in the light-emitting layer 130 is less than 20%, the energy transfer function from the second host material H2 to the light-emitting material D cannot meet the requirements, and the efficiency decay index ΔE of the light-emitting device 100 is relatively high. When the mass proportion of the second host material H2 in the light-emitting layer 130 is greater than 55%, on the one hand, the mass proportion of the first host material H1 in the light-emitting layer 130 is relatively low, affecting the hole transfer rate of the light-emitting device 100; on the other hand, the number of photons emitted by the second host material H2 increases, and the wavelength of the light emitted by the second host material H2 is inconsistent with the wavelength of the target light emitted by the light-emitting device 100, which cannot meet the light emission requirements of the light-emitting device 100; at the same time, the photons emitted by the second host material H2 are prone to quenching, resulting in a decrease in the overall light-emitting efficiency of the light-emitting device 100, and the number of excitons under different grayscales is relatively different, so that the current efficiency decay index ΔE is relatively high. Therefore, by setting the mass proportion of the second main material H2 in the light-emitting layer 130 to be greater than or equal to 20% and less than or equal to 55%, the light emitted by the light-emitting layer 130 can meet the light-emitting requirements of the light-emitting device 100, and the light-emitting efficiency can be improved, so that the current efficiency attenuation index ΔE of the light-emitting device 100 is relatively high.

[0295] Exemplarily, the mass proportion of the second host material H2 in the light-emitting layer 130 is smaller than the mass proportion of the first host material H1 in the light-emitting layer 130 .

[0296] The above is an exemplary description when the second host material H2 is a delayed fluorescent material. The following is an exemplary introduction to the case where a phosphorescent material is used as the second host material H2.

[0297] In some embodiments, the second host material H2 is a phosphorescent material; and, the second host material H2 is a tetradentate ligand material.

[0298] In the related art, a ligand (also called a ligand) refers to an atom, molecule, or ion that can form a bond with a central atom (metal or metalloid).

[0299] When the second host material H2 is a tetradentate ligand material, its structure contains a central atom (metal or metalloid) and four ligands, and the four ligands are all bonded to the central atom.

[0300] It can be understood that when the second host material H2 is a phosphorescent material, on the one hand, the phosphorescent material has a high internal quantum efficiency, can recombine holes and electrons to generate relatively more excitons, and can improve the luminous efficiency of the light-emitting device 100; on the other hand, using the phosphorescent material as the second host material H2, energy can be transferred to the luminescent material D (for example, a fluorescent material emitting blue light) through fluorescence resonance energy transfer, thereby improving energy utilization and luminous efficiency. At the same time, the luminescent material D can reduce the probability of quenching of triplet excitons generated by the recombination of electrons and holes in the second host material H2, and can reduce the difference in the number of excitons under different grayscales, thereby reducing the efficiency attenuation index ΔE of the light-emitting device 100. In addition, the above-mentioned second host material H2 can be compatible with the preparation process of the light-emitting device 100 in the related art, such as the evaporation process, thereby reducing the manufacturing cost of the light-emitting device 100.

[0301] An exemplary structure of the second host material H2 (phosphorescent material) is described below.

[0302] In some examples, the second host material H2 is a tetradentate ligand material formed by platinum (Pt), and the structural formula of the second host material H2 may be as shown below.

[0303]

[0304] It should be noted that the above-listed structural formulas are examples of the structure of the second main material H2, and are not limitations on the second main material H2. Moreover, (H2-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.

[0305] In some embodiments, the mass proportion of the second host material H2 (phosphorescent material) in the light-emitting layer 130 is greater than or equal to 10% and less than or equal to 40%. For example, the mass proportion of the second host material H2 in the light-emitting layer 130 is 10%, 15%, 20%, 30%, 35% or 40%.

[0306] It is understandable that when the mass proportion of the second host material H2 in the light-emitting layer 130 is less than 10%, the energy transfer function from the second host material H2 to the light-emitting material D cannot meet the requirements. When the mass proportion of the second host material H2 in the light-emitting layer 130 is greater than 40%, on the one hand, the mass proportion of the first host material H1 in the light-emitting layer 130 is relatively low, affecting the hole transfer rate of the light-emitting device 100; on the other hand, the number of photons emitted by the second host material H2 increases, and the wavelength of the light emitted by the second host material H2 is inconsistent with the wavelength of the target light emitted by the light-emitting device 100, which cannot meet the light-emitting requirements of the light-emitting device 100; at the same time, the photons emitted by the second host material H2 are prone to quenching, resulting in a decrease in the overall luminous efficiency of the light-emitting device 100, and the number of excitons under different grayscales is relatively different, making the current efficiency attenuation index ΔE relatively high. Therefore, by setting the mass proportion of the second main material H2 in the light-emitting layer 130 to be greater than or equal to 10% and less than or equal to 40%, the light emitted by the light-emitting layer 130 can meet the light-emitting requirements of the light-emitting device 100, and the light-emitting efficiency can be improved, so that the current efficiency attenuation index ΔE of the light-emitting device 100 is relatively high.

[0307] In some embodiments, when at least two 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 light-emitting layer 130 of the first light-emitting device 101 includes a first main material H1, a second main material H2, and a light-emitting material D having a structure as shown in the following formula (RD).

[0308]

[0309] It can be understood that when the structure of the light-emitting material D included in the light-emitting layer 130 of the first light-emitting device 101 is the structure shown in formula (RD), the light-emitting material D is a fluorescent material that emits red light, and can receive the fluorescence resonance energy transfer of the first main material H1 and / or the second main material H2 (for example, a delayed fluorescent material) during the light-emitting process of the first light-emitting device 101 to emit light. At the same time, the light-emitting material D can reduce the probability of quenching of triplet excitons generated by the composite electrons and holes of the second main material H2, reduce the difference in the number of excitons at different gray scales, and reduce the efficiency attenuation index ΔE of the light-emitting device 100.

[0310] It should be noted that (RD) in the above structural formula is a synonym for the structural formula and is not a part of the structural formula.

[0311] In some embodiments, when at least two 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 light-emitting layer 130 of the second light-emitting device 102 includes a first main material H1, a second main material H2, and a light-emitting material D having a structure as shown in the following formula (GD).

[0312]

[0313] It can be understood that when the structure of the light-emitting material D included in the light-emitting layer 130 of the second light-emitting device 102 is the structure shown in formula (GD), the light-emitting material D is a fluorescent material that emits green light, and can receive the fluorescence resonance energy transfer of the first main material H1 and / or the second main material H2 (for example, a delayed fluorescent material) during the light-emitting process of the second light-emitting device 102 to emit light. At the same time, the light-emitting material D can reduce the probability of quenching of triplet excitons generated by the composite electrons and holes of the second main material H2, reduce the difference in the number of excitons under different gray scales, and reduce the efficiency attenuation index ΔE of the light-emitting device 100.

[0314] It should be noted that (GD) in the above structural formula is a synonym for the structural formula and is not a part of the structural formula.

[0315] In order to objectively evaluate the technical effects of the embodiments of the present disclosure, the technical solutions provided by the present disclosure will be described in detail and exemplarily through the following experimental examples and comparative examples.

[0316] In the following examples and comparative examples, Figure 5 As shown, the light-emitting substrate 200 includes a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103, and the light-emitting layers 130 of the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 are made of different materials, and the current efficiency and efficiency attenuation index ΔE of the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 are compared.

[0317] In the following comparative examples and embodiments, the structure of the light-emitting substrate 200 and the testing conditions of the light-emitting substrate 200 are the same.

[0318] For example, Figure 5As shown, the preparation method of the light-emitting substrate 200 is as follows: using the material of the first electrode 110 (indium tin oxide), the material of the hole injection layer 140, the material of the hole transport layer 150, the material of the electron blocking layer 160, the material of the light-emitting layer 130, the material of the hole blocking layer 190, the material of the electron transport layer 180, the material of the electron injection layer 170, and the material of the second electrode 120, the first electrode 110, the hole injection layer 140, the hole transport layer 150, the electron blocking layer 160, the light-emitting layer 130, the hole blocking layer 190, the electron transport layer 180, the electron injection layer 170, and the second electrode 120 are formed in sequence on the backplane (at this time, the pixel defining layer 221 has been formed on the backplane, and an opening Q has been formed on the pixel defining layer 221). The process of forming the first electrode 110 , the hole injection layer 140 , the hole transport layer 150 , the electron blocking layer 160 , the light emitting layer 130 , the hole blocking layer 190 , the electron transport layer 180 , the electron injection layer 170 , and the second electrode 120 is, for example, an evaporation process.

[0319] The light-emitting layer 130 in the following embodiments and comparative examples includes a comparative material, including a comparative material of the first host material and a comparative material of the light-emitting material. The comparative materials involved in the following comparative examples include:

[0320]

[0321] It should be noted that (RA-1), (RA-2), (R-RD), (R-GD) and (R-BD) in the above structural formula are aliases of the structural formula and are not part of the structural formula.

[0322] It should be noted that the thickness and material of the first electrode 110, the hole injection layer 140, the hole transport layer 150, the electron blocking layer 160, the hole blocking layer 190, the electron transport layer 180, the electron injection layer 170, and the second electrode 120 in the embodiment and the comparative example are the same. The thickness of the light-emitting layer 130 of the first light-emitting device 101 is 40nm, the thickness of the light-emitting layer 130 of the second light-emitting device 102 is 30nm, and the thickness of the light-emitting layer 130 of the third light-emitting device 103 is 20nm. Moreover, in the embodiment and the comparative example, the materials of the light-emitting layer 130 of the third light-emitting device 103 are the same, specifically: the light-emitting layer 130 includes a main material and a blue light-emitting material, the structural formula of the main material is shown in (RA-1), and the mass proportion of the main material in the light-emitting layer 130 is 99%; the structural formula of the blue light-emitting material is shown in (R-BD), and the mass proportion of the blue light-emitting material in the light-emitting layer 130 is 1%. The materials of the light-emitting layers 130 of the first light-emitting device 101 and the second light-emitting device 102 are not completely the same.

[0323] The materials of the light-emitting layer 130 of the first light-emitting device 101 and the second light-emitting device 102 in the embodiment and the comparative example are described below.

[0324] In Example 1, the light-emitting layer 130 of the first light-emitting device 101 includes a first host material H1, a second host material H2 and a light-emitting material D. The structural formula of the first host material H1 is shown in (H1-15), and the mass proportion of the first host material H1 in the light-emitting layer 130 is 69%; the structural formula of the second host material H2 is shown in (H2-10), and the mass proportion of the second host material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (RD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%. The light-emitting layer 130 of the second light-emitting device 102 includes a comparative material of the first host material and a comparative material of the light-emitting material. The structural formula of the comparative material of the first host material is shown in (RA-2), and the mass proportion of the comparative material of the first host material in the light-emitting layer 130 is 90%; the structural formula of the comparative material of the light-emitting material is shown in (R-GD), and the mass proportion of the comparative material of the light-emitting material in the light-emitting layer 130 is 10%.

[0325] In Example 2, the light-emitting layer 130 of the first light-emitting device 101 includes a contrast material of the first host material and a contrast material of the light-emitting material. The structural formula of the contrast material of the first host material is shown as (RA-2), and the mass proportion of the contrast material of the first host material in the light-emitting layer 130 is 93%; the structural formula of the contrast material of the light-emitting material is shown as (R-RD), and the mass proportion of the contrast material of the light-emitting material in the light-emitting layer 130 is 7%. The light-emitting layer 130 of the second light-emitting device 102 includes a first host material H1, a second host material H2 and a light-emitting material D. The structural formula of the first host material H1 is shown as (H1-12), and the mass proportion of the first host material H1 in the light-emitting layer 130 is 69%; the structural formula of the second host material H2 is shown as (H2-7), and the mass proportion of the second host material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown as (GD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%.

[0326] In Example 3, the light-emitting layer 130 of the first light-emitting device 101 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-15), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-10), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (RD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%. The light-emitting layer 130 of the second light-emitting device 102 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-12), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-7), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (GD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%.

[0327] In Example 4, the light-emitting layer 130 of the first light-emitting device 101 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-15), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-10), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (RD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%. The light-emitting layer 130 of the second light-emitting device 102 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-4), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-7), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (GD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%.

[0328] In Example 5, the light-emitting layer 130 of the first light-emitting device 101 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-15), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-10), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (RD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%. The light-emitting layer 130 of the second light-emitting device 102 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-11), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-7), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (GD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%.

[0329] In Example 6, the light-emitting layer 130 of the first light-emitting device 101 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-15), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-10), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (RD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%. The light-emitting layer 130 of the second light-emitting device 102 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-13), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-7), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (GD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%.

[0330] In Example 7, the light-emitting layer 130 of the first light-emitting device 101 includes a first host material H1, a second host material H2 and a light-emitting material D. The structural formula of the first host material H1 is shown in (H1-15), and the mass proportion of the first host material H1 in the light-emitting layer 130 is 69%; the structural formula of the second host material H2 is shown in (H2-10), and the mass proportion of the second host material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (RD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%. The light-emitting layer 130 of the second light-emitting device 102 includes a first host material H1 and a second host material H2. The structural formula of the first host material H1 is shown in (H1-12), and the mass proportion of the first host material H1 in the light-emitting layer 130 is 70%; the structural formula of the second host material H2 is shown in (H2-7), and the mass proportion of the second host material H2 in the light-emitting layer 130 is 30%.

[0331] In Example 8, the light-emitting layer 130 of the first light-emitting device 101 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-15), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-10), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (RD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%. The light-emitting layer 130 of the second light-emitting device 102 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-12), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 68%; the structural formula of the second main material H2 is shown in (H2-7), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (GD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 2%.

[0332] In Example 9, the light-emitting layer 130 of the first light-emitting device 101 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-15), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-10), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (RD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%. The light-emitting layer 130 of the second light-emitting device 102 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-11), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 79%; the structural formula of the second main material H2 is shown in (H2-7), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 20%; the structural formula of the light-emitting material D is shown in (GD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%.

[0333] In Example 10, the light-emitting layer 130 of the first light-emitting device 101 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-15), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-10), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (RD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%. The light-emitting layer 130 of the second light-emitting device 102 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-11), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 59%; the structural formula of the second main material H2 is shown in (H2-7), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 40%; the structural formula of the light-emitting material D is shown in (GD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%.

[0334] In Comparative Example 1, the light-emitting layer 130 of the first light-emitting device 101 includes a contrast material of the first host material and a contrast material of the light-emitting material, the structural formula of the contrast material of the first host material is shown as (RA-2), and the mass proportion of the contrast material of the first host material in the light-emitting layer 130 is 93%; the structural formula of the contrast material of the light-emitting material is shown as (R-RD), and the mass proportion of the contrast material of the light-emitting material in the light-emitting layer 130 is 7%. The light-emitting layer 130 of the second light-emitting device 102 includes a contrast material of the first host material and a contrast material of the light-emitting material, the structural formula of the contrast material of the first host material is shown as (RA-2), and the mass proportion of the contrast material of the first host material in the light-emitting layer 130 is 90%; the structural formula of the contrast material of the light-emitting material is shown as (R-GD), and the mass proportion of the contrast material of the light-emitting material in the light-emitting layer 130 is 10%.

[0335] In comparative example 2, the light-emitting layer 130 of the first light-emitting device 101 includes a first main material H1, a second main material H2 and a light-emitting material D. The structural formula of the first main material H1 is shown in (H1-15), and the mass proportion of the first main material H1 in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-10), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (RD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%. The light-emitting layer 130 of the second light-emitting device 102 includes a contrast material of the first main material, a second main material H2 and a light-emitting material D. The structural formula of the contrast material of the first main material is shown in (RA-2), and the mass proportion of the contrast material of the first main material in the light-emitting layer 130 is 69%; the structural formula of the second main material H2 is shown in (H2-7), and the mass proportion of the second main material H2 in the light-emitting layer 130 is 30%; the structural formula of the light-emitting material D is shown in (GD), and the mass proportion of the light-emitting material D in the light-emitting layer 130 is 1%.

[0336] In order to more clearly describe the differences in the structural formulas of the first host material H1, the second host material H2, and the light-emitting material D used in the first light-emitting device 101 and the second light-emitting device 102 and their mass proportions in the light-emitting layer 130 in the embodiments and comparative examples, the following Table 1 is used to more clearly show the structural formulas of the first host material H1, the second host material H2, and the light-emitting material D used in the first light-emitting device 101 and their mass proportions in the light-emitting layer 130 in the embodiments and comparative examples. The following Table 2 is used to more clearly show the structural formulas of the first host material H1, the second host material H2, and the light-emitting material D used in the second light-emitting device 102 and their mass proportions in the light-emitting layer 130 in the embodiments and comparative examples.

[0337] Table 1

[0338]

[0339] Table 2

[0340]

[0341]

[0342] It should be noted that in Table 1 and Table 2, the content of the corresponding column of "first host material H1 and its mass proportion in the light-emitting layer 130" includes the case where the material of the light-emitting layer 130 includes the comparative material of the first host material; the content of the corresponding column of "light-emitting material D and its mass proportion in the light-emitting layer 130" includes the case where the material of the light-emitting layer 130 includes the comparative material of the light-emitting material. "(Hx); y%" in Table 1 and Table 2 means that the corresponding structural formula is Hx and the corresponding mass proportion is y%. For example, the content of the sub-grid corresponding to the first host material H1 and its mass proportion in the light-emitting layer 130 of the second light-emitting device 102 of Example 2 is "(H1-12); 69%", which means that in the light-emitting layer 130 of the second light-emitting device 102 of Example 2, the structural formula of the first host material H1 is shown as (H1-12), and the mass proportion of the first host material H1 in the light-emitting layer 130 is 69%. Among them, the structural formulas represented by (H1-x), (H2-x), (Dx), (RD), (GD), (RA-1), (RA-2), (R-RD), and (R-GD) (x is a positive integer) refer to the above content and are not repeated here. The " / " in Table 1 and Table 2 means that the material corresponding to the sub-grid is not added to the light-emitting layer 130. For example, the light-emitting material D of the second light-emitting device 102 in Example 7 and its mass percentage corresponding to the sub-grid are " / ", which means that the light-emitting material D is not added to the light-emitting layer 130 of the second light-emitting device 102 in Example 7.

[0343] The highest occupied molecular orbital energy level (HOMO), the lowest occupied molecular orbital energy level (LOMO), the singlet energy level (S1), the triplet energy level (T1), the hole mobility, and the electron mobility of the first host material H1, the second host material H2, the first light-emitting material D1, the comparative material of the light-emitting material, and the comparative material of the first host material shown in Table 1 and Table 2 are as shown in Table 3.

[0344] Table 3

[0345]

[0346]

[0347] It should be noted that the units of the highest occupied molecular orbital energy level (HOMO), the lowest occupied molecular orbital energy level (LOMO), and the triplet energy level (T1) in Table 3 are electron volts, with the symbol eV; the units of hole mobility and electron mobility are square centimeters / (volt·second), with the symbol cm 2 / V·s. The “-” in Table 3 means that the present disclosure does not list the parameters corresponding to the sub-grid. For example, the sub-grid corresponding to the electron mobility of the first host material H1-4 is “-”, which means that the electron mobility of the first host material H1-4 of the present disclosure is not listed. Among them, the structural formulas represented by H1-x, H2-x, and RA-x (x is a positive integer) refer to the above content and will not be repeated here.

[0348] Based on the above materials, the current efficiency (cd / A) and efficiency decay index ΔE of the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 of the light-emitting substrate 200 of Examples 1 to 10 and Comparative Examples 1 to 2 are tested. Among them, ER1′, EG1′, and EB1′ are the current efficiencies (cd / A) and efficiency decay indexes ΔE of the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 at the first preset current density I 1 (1mA / cm 2 ) under the normalized current efficiency; ER2′, EG2′, EB2′ are respectively the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 at the second preset current density I 2 (15mA / cm 2 ) under normalized current efficiency; ΔER is the efficiency decay index of the first light emitting device 101, ΔEG is the efficiency decay index of the second light emitting device 102, and ΔEB is the efficiency decay index of the third light emitting device 103. The test results are shown in Tables 4, 5, 6, and 7 below.

[0349] Table 4

[0350] Comparative Example 1 Example 1 Example 2 Example 3 ER1′ 100.0％ 100.0％ 100.0％ 100.0％ ER2 91.7％ 94.1％ 92.2％ 94.1％ ΔER 8.3％ 5.9％ 7.8％ 5.9％ EG1′ 100.0％ 100.0％ 100.0％ 100.0％ EG2′ 89.9％ 90.2％ 94.7％ 94.7％ ΔEG 10.1％ 9.8％ 5.3％ 5.3％ EB1′ 96.5％ 96.5％ 96.5％ 96.5％ EB2′ 99.0％ 99.0％ 99.0％ 99.0％ ΔEB 2.5％ 2.5％ 2.5％ 2.5％ ΔEG-ΔEB 7.6％ 7.3％ 2.8％ 2.8％ ΔER-ΔEB 5.8％ 3.4％ 5.3％ 3.4％ ΔER-ΔEG 1.8％ 3.9％ 2.5％ 0.6％

[0351] Table 5

[0352]

[0353]

[0354] Table 6

[0355] EG1′ EG2′ ΔEG Example 3 99.8％ 94.9％ 4.9％ Example 7 100.0％ 93.0％ 7.0％ Example 8 98.5％ 88.7％ 9.8％

[0356] Table 7

[0357] EG1′ EG2′ ΔEG Example 5 99.3％ 92.9％ 6.4％ Example 9 98.0％ 89.1％ 8.9％ Example 10 99.9％ 95.9％ 4.1％

[0358] Based on the above materials, the normalized current efficiency versus current density curves of the first light emitting device 101, the second light emitting device 102 and the third light emitting device 103 of the light emitting substrate 200 corresponding to Comparative Example 1 were tested, as shown in FIG. Figure 6 The normalized current efficiency versus current density curves of the first light emitting device 101, the second light emitting device 102 and the third light emitting device 103 of the light emitting substrate 200 corresponding to Example 1 are tested, as shown in FIG. Figure 7 The normalized current efficiency versus current density curves of the first light emitting device 101, the second light emitting device 102 and the third light emitting device 103 of the light emitting substrate 200 corresponding to Example 2 are tested, as shown in FIG. Figure 8 The normalized current efficiency versus current density curves of the first light emitting device 101, the second light emitting device 102 and the third light emitting device 103 of the light emitting substrate 200 corresponding to Example 3 are tested, as shown in FIG. Fig. 9 Furthermore, the normalized current efficiency versus current density curves of the second light emitting device 102 of the light emitting substrate 200 corresponding to Examples 3 to 6 and Comparative Example 2 were tested and compared, as shown in FIG. Fig.10 The normalized current efficiency versus current density curves of the second light emitting device 102 of the light emitting substrate 200 corresponding to Embodiment 3, Embodiment 7 and Embodiment 8 are tested and compared, as shown in FIG. Fig.11 The normalized current efficiency versus current density curves of the second light emitting device 102 of the light emitting substrate 200 corresponding to Embodiment 5, Embodiment 9 and Embodiment 10 are tested and compared, as shown in FIG. Fig.12 shown.

[0359] Compared with the comparative example 1, as shown in Table 4, the efficiency attenuation index ΔER of the first light-emitting device 101 is ranked from low to high as follows: embodiment 1 / embodiment 3, embodiment 2, comparative example 1. This is because the material of the light-emitting layer 130 of the first light-emitting device 101 of embodiment 1 and embodiment 3 includes the second main material H2, which can realize the function of energy transmission and improve the energy utilization rate, so that the first light-emitting device 101 can be used at the second preset current density I 2 (15mA / cm 2 ) is effectively improved, which can reduce the efficiency decay index ΔER of the first light-emitting device 101. At the same time, the luminescent material D can receive the fluorescence resonance energy transfer of the second main material H2, reduce the probability of quenching of the triplet excitons of the second main material H2, reduce the difference in the number of excitons under different gray scales, and reduce the efficiency decay index ΔER of the first light-emitting device 101.

[0360] Compared with the comparative example 1, as shown in Table 4, the efficiency attenuation index ΔEG of the second light-emitting device 102 is ranked from low to high as follows: embodiment 2 / embodiment 3, embodiment 1, comparative example 1. This is because the material of the light-emitting layer 130 of the second light-emitting device 102 of embodiment 2 and embodiment 3 includes the second main material H2, which can realize the function of energy transmission and improve the energy utilization rate, so that the second light-emitting device 102 can be used at the second preset current density I 2 (15mA / cm 2 ) is effectively improved, which can reduce the efficiency decay index ΔEG of the second light-emitting device 102. At the same time, the luminescent material D can receive the fluorescence resonance energy transfer of the second main material H2, reduce the probability of quenching of the triplet excitons of the second main material H2, reduce the difference in the number of excitons under different gray scales, and reduce the efficiency decay index ΔEG of the second light-emitting device 102.

[0361] As shown in Table 4, the maximum value of the difference between the efficiency decay index ΔE of any two light-emitting devices 100 in Example 1, Example 2, Example 3 and Comparative Example 1 is 7.3%, 5.3%, 3.4% and 7.6%, respectively, and the order from low to high is: Example 3, Example 2, Example 1, Comparative Example 1. This is because the materials of the light-emitting layer 130 of the first light-emitting device 101 and the second light-emitting device 102 in Example 3 both include the second host material H2, which can realize the function of energy transmission and reduce the efficiency decay index ΔE of the first light-emitting device 101 and the second light-emitting device 102. The materials of the light-emitting layer 130 of the second light-emitting device 102 in Example 2 both include the second host material H2, which can realize the function of energy transmission and reduce the efficiency decay index ΔEG of the second light-emitting device 102, while the materials of the light-emitting layer 130 of the first light-emitting device 101 do not include the second host material H2. The materials of the light-emitting layer 130 of the first light-emitting device 101 of Example 1 include the second main material H2, which can realize the function of energy transmission and reduce the efficiency decay index ΔER of the second light-emitting device 102, while the materials of the light-emitting layer 130 of the second light-emitting device 102 do not include the second main material H2. The materials of the light-emitting layer 130 of the first light-emitting device 101 and the second light-emitting device 102 of Comparative Example 1 do not include the second main material H2, and the function of energy transmission cannot be realized, so that the efficiency decay index ΔE of the first light-emitting device 101 and the second light-emitting device 102 is relatively high. For the description of adding the second main material H2 to reduce the efficiency decay index, please refer to the above content, which will not be repeated here.

[0362] Compared with the comparative example 2, as shown in Table 5, the efficiency decay index ΔEG of the second light-emitting device 102 of the comparative example 2 is significantly higher than the efficiency decay index ΔEG of the second light-emitting device 102 of the embodiments 3 to 6. This is because the light-emitting layer 130 of the second light-emitting device 102 in the comparative example 2 includes the comparative material (RA-2) of the first host material, which is different from the first host materials H1 (H1-12), (H1-4), (H1-11), (H1-

[0363] 13), (RA-2) has a relatively low triplet energy level T1, resulting in the leakage of excitons generated on the second host material H2 (H2-7) to (RA-2), causing the efficiency of the second light-emitting device 102 to decrease. Moreover, at a relatively high second preset current density I 2 (15mA / cm 2 ), the efficiency loss is relatively greater, resulting in a significant increase in the efficiency decay index ΔEG of the second light-emitting device 102.

[0364] Compared with Example 8, as shown in Table 6, the efficiency decay index ΔEG of the second light-emitting device 102 is ranked from low to high as follows: Example 3, Example 7, and Example 8. This is because the mass proportions of the light-emitting material D of the second light-emitting device 102 in the light-emitting layer 130 in Examples 3, 7, and 8 are 1%, 0%, and 2%, respectively. In Example 8, the mass proportion of the light-emitting material D of the second light-emitting device 102 in the light-emitting layer 130 is relatively high, so that the light-emitting material D itself will capture relatively more holes and electrons, affecting the balance of holes and electrons in the light-emitting layer 130. At the same time, since the light-emitting material D of the second light-emitting device 102 is a fluorescent material, the utilization rate of excitons is low. When the light-emitting material D itself captures relatively more holes and electrons, the light-emitting efficiency of the second light-emitting device 102 will be reduced. In addition, the excitons generated by the light-emitting material D capturing holes and electrons are prone to quenching, resulting in a relatively low efficiency decay index ΔEG of the second light-emitting device 102.

[0365] Compared with Example 10, as shown in Table 7, the efficiency decay index ΔEG of the second light-emitting device 102 is ranked from low to high as follows: Example 10, Example 5, and Example 9. This is because the mass proportion of the second host material H2 of the second light-emitting device 102 in the light-emitting layer 130 in Example 10, Example 5, and Example 9 is 40%, 30%, and 20%, respectively. It can be seen that when the mass proportion of the second host material H2 of the second light-emitting device 102 in the light-emitting layer 130 increases, the function of the second host material H2 to transport electrons can be improved, so that during the light-emitting process of the second light-emitting device 102, electrons and holes are more balanced, the exciton yield is increased, and the exciton utilization rate can be improved. The exciton quenching is relatively small, so that the efficiency decay index ΔEG of the second light-emitting device 102 can be effectively reduced.

[0366] It can be seen that the present invention adds the second main material H2 to the material of the light-emitting layer 130, so that the energy transmission during the light-emitting process of the light-emitting device 100 is more sufficient, the energy utilization rate can be improved, and the light-emitting efficiency (such as current efficiency) of the light-emitting device 100 at different gray scales can be effectively improved. In this way, the efficiency decay index ΔE of the light-emitting device 100 can be reduced, and the display difference of the light-emitting device 100 at different gray scales can be effectively reduced; on the other hand, the light-emitting material D can receive the fluorescence resonance energy transfer of the second main material H2, reduce the probability of quenching of triplet excitons generated by the composite electrons and holes of the second main material H2, reduce the difference in the number of excitons at different gray scales, and reduce the efficiency decay index ΔE of the light-emitting device 100.

[0367] 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 substrate, characterized in that: include: substrate; At least two light-emitting devices are disposed on the substrate and arranged along a first direction, wherein the first direction is parallel to the plane where the substrate is located; Wherein, the efficiency decay index of each of the at least two light-emitting devices is less than or equal to 7%; The efficiency decay index refers to the absolute value of the difference between the normalized current efficiency of the light-emitting device at a first preset current density and the normalized current efficiency of the light-emitting device at a second preset current density, and the absolute value of the difference between the first preset current density and the second preset current density is greater than or equal to 14 mA / cm 2 .

2. The light-emitting substrate according to claim 1, characterized in that: An absolute value of a difference between efficiency decay indexes of any two of the at least two light-emitting devices is less than or equal to 6%.

3. The light-emitting substrate according to claim 1 or 2, characterized in that: The at least two light emitting devices include a first light emitting device, a second light emitting device, and a third light emitting device arranged along the first direction; Wherein, the first light emitting device is configured to emit red light; the second light emitting device is configured to emit green light; and the third light emitting device is configured to emit blue light; The efficiency decay index of the second light emitting device is less than or equal to the efficiency decay index of the first light emitting device; the efficiency decay index of the third light emitting device is less than or equal to the efficiency decay index of the first light emitting device.

4. The light-emitting substrate according to claim 3, characterized in that: An absolute value of a difference between efficiency decay indexes of the second light emitting device and the third light emitting device is less than or equal to 3%.

5. The light-emitting substrate according to claim 1, characterized in that: Each of the at least two light emitting devices comprises: a first electrode and a second electrode arranged opposite to each other, and a light emitting layer arranged between the first electrode and the second electrode; The material of the light-emitting layer of each of the at least two light-emitting devices includes a first main material and a light-emitting material; the material of the light-emitting layer of at least one of the at least two light-emitting devices also includes a second main material; the triplet energy level of the first main material is greater than the triplet energy level of the second main material; the triplet energy level of the second main material is greater than or equal to the triplet energy level of the light-emitting material.

6. The light-emitting substrate according to claim 5, characterized in that: A difference between a triplet state energy level of the first host material and a triplet state energy level of the second host material is greater than or equal to 0.15 eV.

7. The light-emitting substrate according to claim 5, characterized in that: The luminescent material is a fluorescent material or a delayed fluorescent material.

8. The light emitting substrate according to any one of claims 5 to 7, characterized in that The mass proportion of the luminescent material in the luminescent layer is less than or equal to 5%.

9. The light-emitting substrate according to claim 5, characterized in that: The hole mobility of the first host material is greater than or equal to the hole mobility of the second host material; and the electron mobility of the second host material is greater than or equal to the electron mobility of the first host material.

10. The light emitting substrate according to claim 5, characterized in that: A ratio of a hole mobility of the first host material to an electron mobility of the second host material is greater than or equal to 0.

1.

11. The light emitting substrate according to claim 5, characterized in that: The hole mobility of the first host material is greater than or equal to 1×10 -6 cm 2 / Vs; and / or, The electron mobility of the second host material is greater than or equal to 1×10 -6 cm 2 / Vs.

12. The light emitting substrate according to claim 5, characterized in that: The first host material is selected from any one of the structures shown in the following general formula (I); wherein Ar1 is selected from a substituted or unsubstituted first group; Ar2 is selected from a substituted or unsubstituted second group; L is selected from any one of a single bond and a substituted or unsubstituted arylene group; m and n are the same or different and are independently selected from positive integers greater than or equal to 1; The first group is selected from any one of the structures shown in the following general formula (IA); The second group is selected from any one of the structures shown in the following general formula (IB); Wherein, the value of p is selected from any one of 0, 1 and 2; Z and X are the same or different and are independently selected from O, S, N (R a ) and C(R b R c ) R1, R2, R3, R4, R5, R6, R7, R8, R a , R b and R c are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, nitrile, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted haloalkoxy, substituted or unsubstituted aryl, substituted or unsubstituted haloaryl, substituted or unsubstituted silyl and substituted or unsubstituted heterocycle; R9 and R 10 the same or different, and independently selected from any one of hydrogen, deuterium, halogen, amino, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted silanyl, substituted or unsubstituted germanyl, substituted or unsubstituted borane, substituted or unsubstituted selenanyl, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heteroalkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl.

13. The light emitting substrate according to claim 12, characterized in that: The first host material is selected from any one of the structures shown in the following general formula (IA); 14. The light emitting substrate according to claim 12, characterized in that: The first main material is selected from any one of the structures represented by the following general formula (I-B1) and general formula (I-B2); 15. The light emitting substrate according to claim 12, characterized in that: The first host material is selected from any one of the structures represented by the following general formula (I-C1), general formula (I-C2), general formula (I-C3), general formula (I-C4), general formula (I-C5), general formula (I-C6), general formula (I-C7) and general formula (I-C8); Wherein, Z1 and Z2 are the same or different and are independently selected from O, S, N (R a ) and C(R b R c ) 16. The light emitting substrate according to any one of claims 12 to 15, characterized in that: The second group is selected from any one of the structures represented by the following general formula (IB-1) and general formula (IB-2); Wherein, Y is selected from O, S, N (R d )、C(R e R f )、Si(R g R h ) and Ge(R i R j ) R d , R e , R f , R g , R h , R i and R j are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, nitrile, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted haloalkoxy, substituted or unsubstituted aryl, substituted or unsubstituted haloaryl, substituted or unsubstituted silyl and substituted or unsubstituted heterocycle.

17. The light emitting substrate according to claim 16, characterized in that: In the case where the first host material is selected from any one of the structures represented by the general formula (IA), and the second group is selected from any one of the structures represented by the general formula (IB-1), X is selected from O, S and C (R b R c ) 18. The light emitting substrate according to claim 16, characterized in that: The mass proportion of the first host material in the light-emitting layer is greater than or equal to 40% and less than or equal to 90%.

19. The light emitting substrate according to claim 5, characterized in that: The second main material is selected from any one of the structures shown in the following general formula (ⅠI); Wherein, X1 and X2 are the same or different and are independently selected from N and C (R k ) R A , R B , R D and R E are the same or different, and are independently selected from a substituted or unsubstituted substituent group IIA, and a substituted or unsubstituted substituent group IIB, and in R A , R B , R D and R E Contains at least two substituted or unsubstituted substituent groups IIA and at least one substituted or unsubstituted substituent group IIB; The substituent group IIA is selected from any one of IIA-a to IIA-i; The substituent group IIB is selected from any one of IIB-a to IIB-j; Wherein, Z3 is selected from C(R m R n )、N(R p ), any one of O and S; X3 is selected from any one of O and S; R k , R m , R n , R p , R 11 and R 12 are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, nitrile, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted haloalkoxy, substituted or unsubstituted aryl, substituted or unsubstituted haloaryl, substituted or unsubstituted silyl and substituted or unsubstituted heterocycle.

20. The light emitting substrate according to claim 19, characterized in that: The mass proportion of the second host material in the light-emitting layer is greater than or equal to 20% and less than or equal to 55%.

21. The light emitting substrate according to claim 5, characterized in that: The second host material is a phosphorescent material; and the second host material is a tetradentate ligand material.

22. The light-emitting substrate according to claim 21, characterized in that: The mass proportion of the second host material in the light-emitting layer is greater than or equal to 10% and less than or equal to 40%.

23. The light emitting substrate according to claim 5, characterized in that: In the case where the at least two light-emitting devices include a first light-emitting device, a second light-emitting device, and a third light-emitting device, the light-emitting layer of the first light-emitting device includes the first host material, the second host material, and a light-emitting material having a structure shown in the following formula (RD); and / or, The light-emitting layer of the second light-emitting device includes the first host material, the second host material, and a light-emitting material having a structure as shown in the following formula (GD); 24. A display panel, characterized in that: A light-emitting substrate comprising the light-emitting substrate as claimed in any one of claims 1 to 23; It also includes: at least two pixel driving circuits, each of the at least two pixel driving circuits is electrically connected to one of the light-emitting devices and is used to drive the light-emitting device to emit light.

25. A display device, characterized in that: comprising the display panel as claimed in claim 24; It also includes: a driving chip, and the driving chip is used to drive the display panel to display.

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