Functional layer forming material, preparation method for functional layer, and light-emitting device

Abstract

The present invention relates to the field of display technology, and provides a functional layer forming material, a preparation method for a functional layer, and a light-emitting device. The functional layer forming material comprises a functional material and a cross-linking material, wherein the ratio of the mass of the cross-linking material to that of the functional material is greater than 0, but less than or equal to 15%. The cross-linking material is configured to react with the functional material under a first preset condition, so as to generate a cross-linked functional material. In the cross-linked functional material, a chain segment corresponding to the functional material is a first chain segment, and a chain segment corresponding to the cross-linking material is a second chain segment. Under a second preset condition, the cross-linked functional material can undergo a decomposition reaction; and in the decomposition reaction, the position where the cross-linked functional material is decomposed is located at the joint of the first chain segment and the second chain segment, or is located in the middle of the second chain segment. The functional layer forming material is used for preparing a functional layer.

Description

Functional layer forming material, functional layer preparation method and light-emitting device

[0001] This application claims priority to Chinese patent application No. 202410084387.7, filed on January 19, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the field of display technology, and in particular to a functional layer forming material, a functional layer preparation method, and a light-emitting device. Background Art

[0003] Quantum dots (QDs), as a new type of luminescent material, offer advantages such as high light color purity, high quantum efficiency, adjustable light color, and long lifespan, making them a research hotspot for new LED (light emitting diode) luminescent materials. Consequently, quantum dot light emitting diodes (QLEDs), which use quantum dot luminescent materials as the light-emitting layer, have become a major research focus for new display devices. Summary of the Invention

[0004] On the one hand, a functional layer forming material is provided. The functional layer forming material includes a functional material and a cross-linking material. The ratio between the mass of the cross-linking material and the mass of the functional material is greater than 0 and less than or equal to 15%. The cross-linking material is configured to react with the functional material under a first preset condition to generate a cross-linked functional material. In the cross-linked functional material, the segment corresponding to the functional material is the first segment, and the segment corresponding to the cross-linking material is the second segment. Under a second preset condition, the cross-linked functional material can undergo a decomposition reaction; in the decomposition reaction, the location where the cross-linked functional material decomposes is located at the connection between the first segment and the second segment, or at the middle of the second segment.

[0005] In some embodiments, the cross-linked functional material comprises a plurality of first segments and a plurality of second segments. If, during a decomposition reaction, the cross-linked functional material decomposes at the junction of the first segment and the second segment, a portion of the first segment remains connected to a portion of the second segment after the decomposition reaction. If, during a decomposition reaction, the cross-linked functional material decomposes at the middle of the second segment, a portion of the second segment remains undecomposed after the decomposition reaction.

[0006] In some embodiments, the cross-linking material includes a plurality of first groups and at least one second group. The plurality of first groups are located at the ends of the cross-linking material and are capable of reacting with the functional material under a first predetermined condition. The at least one second group is located in the middle of the cross-linking material and is capable of decomposing under a second predetermined condition.

[0007] In some embodiments, the first group is a first photosensitive group, and the first preset condition includes irradiating a first light.

[0008] In some embodiments, the plurality of first groups are the same or different and are independently selected from any one of a benzophenone group, an azide group, a diazo group, and a diazirine group.

[0009] In some embodiments, the cross-linking material and the functional material undergo a carbon-hydrogen insertion reaction, or an addition reaction, to generate a cross-linked functional material.

[0010] In some embodiments, the second group is a second photosensitive group, and the second preset condition includes irradiating a second light. When the first group is a first photosensitive group, the second light is different from the first light.

[0011] In some embodiments, the second group is a structure represented by the following formula (IA-1).

[0012] Wherein, * is the first connection site.

[0013] In some embodiments, the second group is a first thermosensitive group, and the second preset condition includes applying heating means.

[0014] In some embodiments, when the cross-linking material includes one second group, the second group is any one of an azo group, a peroxide group, a persulfide group, an acetyl ketone group, and a methylthiophenol group. When the cross-linking material includes multiple second groups, the multiple second groups are the same or different and are independently selected from any one of an azo group, a peroxide group, a persulfide group, an acetyl ketone group, and a methylthiophenol group.

[0015] In some embodiments, when the second group is an azo group, the second group has a structure represented by the following general formula (IA-2).

[0016] Wherein, * represents the first attachment site. R1, R2, R3, and R4 are the same or different and are independently selected from any one of hydrogen, a C1-C40 substituted or unsubstituted saturated or unsaturated linear or branched alkyl group, a C1-C40 substituted or unsubstituted ester group, a C1-C40 substituted or unsubstituted nitrile group, a C3-C40 substituted or unsubstituted cycloalkyl group, a 3- to 40-membered substituted or unsubstituted heterocyclic group, a C6-C40 substituted or unsubstituted aryl group, and a 5- to 40-membered substituted or unsubstituted heteroaryl group, or may be linked with adjacent groups to form a substituted or unsubstituted 3- to 40-membered ring.

[0017] In some embodiments, R1 and R4 are the same and are selected from any one of the structures represented by the following formulae (IA-2-1) to (IA-2-7).

[0018] wherein a, b and c are the same or different and are independently selected from any one of 0, 1, 2 and 3.

[0019] In some embodiments, R2 and R3 are the same and are selected from any one of the structures shown in the following formulas (IA-2-8) to (IA-2-16).

[0020] wherein d and e are the same or different and are independently selected from any one of 0, 1, 2, 3, 4, 5 and 6.

[0021] In some embodiments, when the second group is a peroxide group, the second group is selected from any one of the structures shown in the following formulas (IA-3) to (IA-8);

[0022] Wherein, * is the first attachment site. f, g, h and i are the same or different and are independently selected from any one of 0, 1, 2, 3, 4, 5 and 6.

[0023] In some embodiments, when the second group is a persulfate group, the second group is selected from any one of the structures shown in the following formulas (IA-9) to (IA-14);

[0024] wherein * is the first attachment site, j, k, m, and n are the same or different and are independently selected from any one of 0, 1, 2, 3, 4, 5, and 6.

[0025] In some embodiments, when the second group is an acetyl ketone group, the second group is a structure as shown in the following formula (IA-15);

[0026] Wherein, * is the first connection site.

[0027] In some embodiments, when the second group is a methylthiophenol group, the second group has a structure represented by the following general formula (IA-16).

[0028] Wherein, * is the first connection site.

[0029] In some embodiments, the cross-linking material is selected from any one of the structures represented by the following formula (I) and formula (II).

[0030] G is selected from any one of the structures represented by the following general formula (IB).

[0031] Wherein, J is the first group. # is the second attachment site. A is the second group; if the second group includes the first attachment site, the first attachment site is connected to the second attachment site. L1, L2, and L3 are the same or different and are independently selected from any one of a C1-C40 substituted or unsubstituted amide group, a C1-C40 substituted or unsubstituted ester group, a C1-C40 substituted or unsubstituted saturated or unsaturated linear or branched alkyl group, a C3-C40 substituted or unsubstituted cycloalkyl group, a 3- to 40-membered substituted or unsubstituted heterocyclic group, a C6-C40 substituted or unsubstituted aryl group, and a 5- to 40-membered heteroaryl group. E1 and E2 are the same or different and are independently selected from carbon, oxygen, sulfur, selenium, sulfur, phosphorus, a C1-C40 substituted or unsubstituted saturated or unsaturated linear or branched alkyl group, a C3-C40 substituted or unsubstituted cycloalkyl group, a 3- to 40-membered substituted or unsubstituted heterocyclic group, a C6-C40 substituted or unsubstituted aryl group, and a 5- to 40-membered substituted or unsubstituted heteroaryl group. x, y, and w are the same or different and are independently selected from 1, 2, 3, 4, 5, and 6. z is selected from 2, 3, 4, 5, and 6.

[0032] In some embodiments, L1, L2, and L3 are the same or different and are independently selected from any one of the structures represented by the following general formulas (IC-1) to (IC-3);

[0033] wherein R5 and R6 are the same or different and are independently selected from any one of a C1-C40 substituted or unsubstituted saturated or unsaturated straight-chain or branched alkyl group, a C1-C40 substituted or unsubstituted nitrile group, a C3-C40 substituted or unsubstituted cycloalkyl group, a 3-40 membered substituted or unsubstituted heterocyclic group, a C6-C40 substituted or unsubstituted aryl group, and a 5-40 membered substituted or unsubstituted heteroaryl group; and at least one of R5 and R6 is a C1-C6 saturated substituted or unsubstituted straight-chain or branched alkyl group.

[0034] In some embodiments, E1 and E2 are the same or different and are independently selected from any one of the structures represented by the following general formulas (ID-1) to (ID-6).

[0035] wherein L is L1, L2 or L3. p, r and s are the same or different and are independently selected from any one of 1, 2, 3, 4, 5 and 6.

[0036] In another aspect, a method for preparing a functional layer is provided. The method comprises providing a material for forming the functional layer; the material for forming the functional layer comprises a functional material and a cross-linking material; the ratio of the mass of the cross-linking material to the mass of the functional material is greater than 0 and less than or equal to 15%. Under first preset conditions, the cross-linking material and the functional material react to form a cross-linked functional material; in the cross-linked functional material, the segment corresponding to the functional material is a first segment, and the segment corresponding to the cross-linking material is a second segment. Under second preset conditions, the cross-linked functional material undergoes a decomposition reaction to form the functional layer; during the decomposition reaction, the cross-linked functional material decomposes at the junction of the first segment and the second segment, or at the middle of the second segment.

[0037] In some embodiments, the first preset condition is an exposure condition. When the functional layer is formed, the quantum dot light-emitting layer is also formed.

[0038] The functional layer preparation method specifically includes: forming a first initial functional layer, wherein the material of the first initial functional layer includes a functional layer forming material; exposing the first initial functional layer, wherein the exposed portion of the first initial functional layer forms a second initial functional layer, wherein the material of the second initial functional layer includes a cross-linked functional material; developing the unexposed portion of the first initial functional layer; and causing the cross-linked functional material in the second initial functional layer to undergo a decomposition reaction under a second preset condition.

[0039] A method for preparing a quantum dot light-emitting layer includes forming an initial quantum dot light-emitting layer, exposing the initial quantum dot light-emitting layer, and developing the initial quantum dot light-emitting layer.

[0040] Among them, developing the unexposed portion of the first initial functional layer and developing the initial quantum dot light-emitting layer are performed after exposing the first initial functional layer and before causing the cross-linked functional material in the second initial functional layer to undergo a decomposition reaction under second preset conditions.

[0041] In another aspect, a light-emitting device is provided. The light-emitting device includes an anode, a cathode, and a functional layer located between the anode and the cathode. The material forming the functional layer includes the material forming the functional layer as described in any of the above embodiments.

[0042] In some examples, the functional layer includes one or more of a quantum dot light emitting layer, a hole transport layer, a hole injection layer, an electron blocking layer, an electron transport layer, an electron injection layer, and a hole blocking layer.

[0043] In some embodiments, the functional layer is located between the anode and the quantum dot light-emitting layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] To more clearly illustrate the technical solutions of the present disclosure, the following briefly introduces the drawings required for use in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure, and those skilled in the art can also derive other drawings based on these drawings. Furthermore, the drawings described below are schematic diagrams and are not intended to limit the actual dimensions of the products, actual processes of the methods, actual timing of signals, and the like involved in the embodiments of the present disclosure.

[0045] FIG1 is a step diagram of a method for preparing a light-emitting substrate according to some embodiments of the present disclosure;

[0046] FIG2 is a structural diagram of a light-emitting substrate according to some embodiments of the present disclosure;

[0047] FIG3 is another step diagram of a method for preparing a light-emitting substrate according to some embodiments of the present disclosure;

[0048] FIG4 is another structural diagram of a light-emitting substrate according to some embodiments of the present disclosure;

[0049] FIG5 is a structural diagram of a light emitting device according to some embodiments of the present disclosure;

[0050] FIG6 is a data comparison diagram of external quantum efficiency of light-emitting devices according to some embodiments of the present disclosure;

[0051] FIG7 is a structural diagram of a single hole device according to some embodiments of the present disclosure;

[0052] FIG8 is a graph showing the variation of current density with voltage for a single hole device according to some embodiments of the present disclosure;

[0053] FIG9 is a graph showing a change in current density versus voltage of a light emitting device according to some embodiments of the present disclosure;

[0054] FIG10 is another structural diagram of a light emitting device according to some embodiments of the present disclosure;

[0055] FIG11 is a flow chart of a method for preparing a functional layer provided in some embodiments of the present disclosure;

[0056] FIG12 is a step diagram of a method for preparing a functional layer provided in some embodiments of the present disclosure. DETAILED DESCRIPTION

[0057] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the embodiments described are only some embodiments of the present disclosure, not all embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present disclosure.

[0058] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and its other forms, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open and inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" are intended to indicate that the particular features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the particular features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0059] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0060] “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.

[0061] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0062] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of deviation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0063] As used herein, "parallel", "perpendicular", and "equal" include the situations described and situations similar to the situations described, and the range of the similar situations is within an acceptable deviation range, wherein the acceptable deviation range is as determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity can also be, for example, a deviation within 5°. "Equal" includes absolute equality and approximate equality, wherein the acceptable deviation range of approximate equality can be, for example, that the difference between the two equals is less than or equal to 5% of either one.

[0064] It will be understood that when a layer or element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present therebetween.

[0065] Exemplary embodiments are described herein with reference to cross-sectional and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are contemplated. Therefore, the exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include deviations in shape due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device and are not intended to limit the scope of the exemplary embodiments.

[0066] It should be noted that, for example, 1 / 2 in the drawings of this disclosure represents structure 1 and structure 2, and both structures can refer to this structure. For example, 20 / R in the drawings represents light-emitting device 20 and red light-emitting device R, and both can refer to this structure. Other similar reference numerals in the drawings also follow the above description.

[0067] Based on the quantum confinement effect, quantum dots (QDs) have excellent luminescence properties such as broadband absorption, narrowband emission, and continuously adjustable peak positions. At the same time, quantum dots are solution processable, which avoids the use of expensive vacuum equipment. As a result, quantum dot light emitting diodes (QLEDs) using quantum dots as luminescent materials are considered to be the most promising next-generation self-luminous display technology. They are widely used in display lighting, solar cells, and photoelectric detection, for example, in new high-resolution display devices (electroluminescent or photoluminescent). Compared with organic light emitting diodes (OLEDs), QLEDs have the advantages of lower power consumption, higher color purity, and a wider color gamut.

[0068] In the fabrication of QLED light-emitting devices, precise sub-pixel fabrication is a prerequisite for achieving high-resolution displays on QLED substrates. When using a solution-based method to prepare the quantum dot light-emitting layer of a QLED light-emitting device, patterning involves pixelating the solution-based quantum dots. The main fabrication technologies for the light-emitting layer of quantum dot light-emitting diodes include inkjet printing, photolithography, and transfer printing. Photolithography is a promising method for fabricating high-resolution quantum dot light-emitting diodes.

[0069] Photolithography technology, that is, the technology of patterning quantum dots by exposure and development. Using quantum dot materials with photosensitive properties, the direct patterning of quantum dot films on substrates is achieved through mature photolithography and development processes. This is an effective way to achieve high pixel density (high resolution) for QLED light-emitting substrates. For example, surface ligands with photoresponsiveness give quantum dots the function of direct photolithographic patterning. The main principle is to use photochemical reactions such as decomposition or cross-linking of photosensitive groups to change the colloidal stability of quantum dots before and after the photochemical reaction, and achieve the purpose of selective patterning through development.

[0070] As shown in Figure 1, an exemplary process for preparing a quantum dot light-emitting layer 14 of a light-emitting substrate 10 is described. Referring to the last sub-figure in Figure 1 (i.e., the sub-figure corresponding to step S8), the light-emitting substrate 10 comprises a substrate 11, a pixel-defining layer 12 disposed on the substrate 11, and a plurality of light-emitting devices, each of which comprises a quantum dot light-emitting layer 14. The pixel-defining layer 12 has a plurality of openings Q, and the plurality of light-emitting devices can be disposed in a one-to-one correspondence with the plurality of openings Q.

[0071] Exemplarily, the plurality of light-emitting devices include a red light-emitting device R, a green light-emitting device G, and a blue light-emitting device B. The following describes a process for sequentially forming the quantum dot light-emitting layer 14R of the red light-emitting device R, the quantum dot light-emitting layer 14G of the green light-emitting device G, and the quantum dot light-emitting layer 14B of the blue light-emitting device B.

[0072] As shown in FIG1 , the process includes steps S1 to S8 .

[0073] In order to improve the efficiency of electron and hole injection into the quantum dot light-emitting layer 14, a front film layer 13A is further provided between the substrate 11 and the quantum dot light-emitting layer 14. The front film layer 13A is, for example, one or two of an electron injection layer, an electron transport layer and a hole blocking layer, or one or two of a hole injection layer, a hole transport layer and an electron blocking layer.

[0074] S1: A red quantum dot (RQD) luminescent material is applied to the side of the front film layer 13A facing away from the substrate 11 to form a red initial quantum dot luminescent layer 14Ri. The red initial quantum dot luminescent layer 14Ri is exposed. The area where the red light-emitting device R is preformed is the exposed area. The red initial quantum dot luminescent layer 14Ri in the exposed area becomes the quantum dot luminescent layer 14R of the red light-emitting device R.

[0075] S2: Development, removing the red initial quantum dot light-emitting layer 14Ri in areas other than the exposed area in S2.

[0076] S3: coating a green quantum dot (GQD) luminescent material on the quantum dot luminescent layer 14R of the red light emitting device R and the side of the front film layer 13A away from the substrate 11 to form a green initial quantum dot luminescent layer 14Gi.

[0077] S4: Expose the green initial quantum dot light-emitting layer 14Gi. The area where the green light-emitting device G is pre-formed is the exposed area. The green initial quantum dot light-emitting layer 14Gi in the exposed area forms the quantum dot light-emitting layer 14G of the green light-emitting device G.

[0078] S5: Development, removing the green initial quantum dot light-emitting layer 14Gi in areas other than the exposed area in S4.

[0079] S6: Coat blue quantum dot (BQD) luminescent material on the quantum dot luminescent layer 14G of the green light-emitting device G, the quantum dot luminescent layer 14R of the red light-emitting device R, and the side of the front film layer 13A away from the substrate 11 to form a blue initial quantum dot luminescent layer 14Bi.

[0080] S7: Expose the blue initial quantum dot light-emitting layer 14Bi. The area where the blue light-emitting device B is pre-formed is the exposed area. The blue initial quantum dot light-emitting layer 14Bi in the exposed area forms the quantum dot light-emitting layer 14B of the blue light-emitting device B.

[0081] S8: Development, removing the blue initial quantum dot light-emitting layer 14Bi in areas other than the exposed area in S7.

[0082] However, in the actual process of preparing the quantum dot light-emitting layer 14 of the light-emitting substrate 1, as shown in FIG2, due to certain interactions between the quantum dot light-emitting material and the materials of the adjacent film layers, the interactions include but are not limited to van der Waals forces, electrostatic forces, gravity, capillary forces, etc., so that the patterning method has the problem of incomplete elution of the quantum dot light-emitting material of the previous color (such as red quantum dot light-emitting material), which will cause the quantum dot light-emitting material of the previous color (such as red quantum dot light-emitting material) to remain on the side of the quantum dot light-emitting layer of the next color (such as the quantum dot light-emitting layer 14G of the green light-emitting device G) close to the substrate 11. At the same time, the patterning method also has the problem of incomplete elution of the quantum dot light-emitting material of the next color (such as blue quantum dot light-emitting material), which will cause the quantum dot light-emitting material of the next color (such as blue quantum dot light-emitting material) to remain on the side of the quantum dot light-emitting layer of the previous color (such as the quantum dot light-emitting layer 14G of the green light-emitting device G) away from the substrate 11.

[0083] For example, as shown in FIG2 , taking the sequential formation of the quantum dot light-emitting layer 14R of the red light-emitting device R, the quantum dot light-emitting layer 14G of the green light-emitting device G, and the quantum dot light-emitting layer 14B of the blue light-emitting device B as an example, on the side of the quantum dot light-emitting layer 14R of the red light-emitting device R away from the substrate 11, there will be a residual layer G0 formed by the green quantum dot light-emitting material and a residual layer B0 formed by the blue quantum dot light-emitting material. On the side of the quantum dot light-emitting layer 14G of the green light-emitting device G close to the substrate 11, there will be a residual layer R0 formed by the red quantum dot light-emitting material. On the side of the quantum dot light-emitting layer 14G of the green light-emitting device G close to the substrate 11, there will be a residual layer B0 formed by the blue quantum dot light-emitting material. On the side of the quantum dot light-emitting layer 14B of the blue light-emitting device B close to the substrate 11, there will be a residual layer R0 formed by the red quantum dot light-emitting material and a residual layer G0 formed by the green quantum dot light-emitting material.

[0084] The residual layer formed by this quantum dot luminescent material will cause color mixing problems. When the light-emitting device is lit, the luminescent spectrum is likely to be impure, thus affecting the device performance.

[0085] Therefore, in order to overcome the problem of impure luminescent spectrum of the luminescent substrate. In some embodiments, as shown in Figures 3 and 4, a photolithography process of a photolithographic sacrificial layer is adopted. Specifically, a material that can undergo a cross-linking reaction under light irradiation is used as the front film layer material of the quantum dot light-emitting layer, so that the front film layer of the quantum dot light-emitting layer is used as an auxiliary sacrificial layer, and the portion of the quantum dot light-emitting material located in the remaining area except the area where the target opening is located is removed to avoid the quantum dot light-emitting material from forming residues in the remaining areas except the area where the target opening is located. In this way, the problem of the quantum dot light-emitting material of the previous color remaining on the side of the quantum dot light-emitting layer of the next color close to the substrate and the quantum dot light-emitting material of the next color remaining on the side of the quantum dot light-emitting layer of the previous color away from the substrate can be solved, thereby solving the color mixing problem caused by the residual layer formed by the quantum dot light-emitting material.

[0086] As shown in FIG3 , the following describes a process for preparing the quantum dot light-emitting layer 14 of the light-emitting substrate 10 by sequentially forming the quantum dot light-emitting layer 14R of the red light-emitting device R, the quantum dot light-emitting layer 14G of the green light-emitting device G, and the quantum dot light-emitting layer 14B of the blue light-emitting device B using the hole transport layer as a photolithography sacrificial layer. The process includes steps M1 to M12.

[0087] M1: A first initial hole transport layer 151i is formed on the side of the front film layer 13B away from the substrate 11. The materials of the first initial hole transport layer 151i include: a first hole transport material and a second photosensitive material. The front film layer 13B is, for example, an anode or a hole injection layer.

[0088] M2: A red initial quantum dot light-emitting layer 14Ri is formed on the side of the first initial hole transport layer 151i away from the substrate 11. The red initial quantum dot light-emitting layer 14Ri includes a red quantum dot light-emitting material and a first photosensitive material. The first region W1 where the red light-emitting device R is located is exposed.

[0089] In some examples, the first region W1 is exposed in M2 so that the red quantum dot luminescent material and the first photosensitive material of the first region W1 are cross-linked to generate a red cross-linked quantum dot luminescent material, and at the same time, the first hole transport material and the second photosensitive material of the first region W1 are cross-linked to generate a first cross-linked hole transport material.

[0090] In other examples, M1 further includes exposing the first region W1 where the red light-emitting device R is located, so that the first hole transport material and the second photosensitive material in the first region W1 are cross-linked to form a first cross-linked hole transport material. In this case, M2 also exposes the first region W1 so that the red quantum dot light-emitting material and the first photosensitive material in the first region W1 are cross-linked to form a red cross-linked quantum dot light-emitting material.

[0091] M3: Using a first solvent to dissolve the portion of the red initial quantum dot light-emitting layer 14Ri located in the second region W2, thereby removing the portion of the red initial quantum dot light-emitting layer 14Ri located in the second region W2. The second region W2 is the remaining region of the plurality of light-emitting devices 20 except for the region where the red light-emitting device R is located.

[0092] For example, portions of the red quantum dot luminescent material and the first photosensitive material close to the substrate 11 may remain, and a first temporary residual layer 31 may remain in the second region W2 .

[0093] M4: A second solvent is used to dissolve the portion of the first initial hole transport layer 151i located in the second region W2. The portion of the first initial hole transport layer 151i located in the second region W2 and away from the substrate 11 is removed, while the portion of the first initial hole transport layer 151i located in the second region W2 and close to the substrate 11 is retained, forming a first initial residual pattern 32. The first hole transport layer 151 and quantum dot light-emitting layer 14R of the red light-emitting device R are obtained.

[0094] In some examples, the light emitting substrate 10 further includes a pixel defining layer 12 , and a first initial residual pattern 32 is formed on a side of the pixel defining layer 12 away from the substrate 11 .

[0095] It should be understood that when removing the portion of the first initial hole transport layer 151i located in the second region W2 and away from the substrate 11, the first temporary residual layer 31 is also removed, which can effectively prevent the red quantum dot light-emitting material from remaining in the second region W2.

[0096] M5: A second initial hole transport layer 152i is formed on the side of the quantum dot light-emitting layer 14R with the red light-emitting device R and the first initial residual pattern 32 away from the substrate 11. The material of the second initial hole transport layer 152i includes: a second hole transport material and a fourth photosensitive material.

[0097] M6: A green initial quantum dot light-emitting layer 14Gi is formed on the side of the second initial hole transport layer 152i away from the substrate 11. The green initial quantum dot light-emitting layer 14Gi includes a green quantum dot light-emitting material and a third photosensitive material. The third region W3 where the green light-emitting device G is located is exposed.

[0098] Here, for the description of the exposure method of the second initial hole transport layer 152i and the green initial quantum dot light-emitting layer 14Gi, please refer to the description of the exposure method of the first initial hole transport layer 151i and the red initial quantum dot light-emitting layer 14Ri in M1 and M2, which will not be repeated here.

[0099] In some examples, when the third region W3 where the green light emitting device G is located is exposed, the first initial residual pattern 32 located in the third region W3 is converted into a first residual pattern 32A.

[0100] M7: Using a third solvent, dissolve the portion of the green initial quantum dot light-emitting layer 14Gi located in the fourth region W4, thereby removing the portion of the green initial quantum dot light-emitting layer 14Gi located in the fourth region W4. The fourth region W4 is the remaining region of the plurality of light-emitting devices 20 excluding the region where the green light-emitting device G is located.

[0101] Exemplarily, the green quantum dot light-emitting material and the third photosensitive material may remain near the substrate 11 , and a second temporary residual layer 33 may remain in the fourth region W4 .

[0102] M8: A fourth solvent is used to dissolve the portion of the second initial hole transport layer 152i located in the fourth region W4, and the portion of the green initial quantum dot light-emitting layer 14Gi located in the fourth region W4 and away from the substrate 11 is removed. The portion of the second initial hole transport layer 152i located in the fourth region W4 and close to the substrate 11 is retained to form a second initial residual pattern 34, and the second hole transport layer 152 and quantum dot light-emitting layer 14G of the green light-emitting device G are obtained.

[0103] In some examples, the light emitting substrate 10 further includes a pixel defining layer 12 , and a second initial residual pattern 34 is formed on a side of the pixel defining layer 12 away from the substrate 11 .

[0104] It should be understood that when removing the portion of the second initial hole transport layer 152i located in the fourth region W4 and away from the substrate 11, the second temporary residual layer 33 is also removed, which can effectively prevent the green quantum dot luminescent material from remaining in the fourth region W4.

[0105] M9: A third initial hole transport layer 153i is formed on the side of the second initial residual pattern 34 away from the substrate 11 on which the quantum dot light-emitting layer 14R of the red light-emitting device R, the quantum dot light-emitting layer 14G of the green light-emitting device R and the second initial residual pattern 34 are formed. The material of the third initial hole transport layer 153i includes: a third hole transport material and a sixth photosensitive material.

[0106] M10: forming a blue initial quantum dot light-emitting layer 14Bi on the side of the third initial hole transport layer 153i away from the substrate 11. The blue initial quantum dot light-emitting layer 14Bi includes a blue quantum dot light-emitting material and a fifth photosensitive material. Exposing the fifth region W5 where the blue light-emitting device B is located.

[0107] Here, for the description of the exposure method of the third initial hole transport layer 153i and the blue initial quantum dot light-emitting layer 14Bi, please refer to the description of the exposure method of the first initial hole transport layer 151i and the red initial quantum dot light-emitting layer 14Ri in M1 and M2, which will not be repeated here.

[0108] In some examples, when the fifth region W5 where the blue light-emitting device B is located is exposed, the first initial residual pattern 32 in the fifth region W5 is converted into a first residual pattern 32A, and the second initial residual pattern 34 in the fifth region W5 is converted into a second residual pattern 34A.

[0109] M11: Using a fifth solvent, dissolve the portion of the blue initial quantum dot light-emitting layer 14Bi located in the sixth region W6, thereby removing the portion of the blue initial quantum dot light-emitting layer 14Bi located in the sixth region W6. The sixth region W6 is the remaining region of the plurality of light-emitting devices 20 excluding the region where the blue light-emitting device B is located.

[0110] Exemplarily, the blue quantum dot luminescent material and the fifth photosensitive material may remain near the substrate 11 , and a third temporary residual layer 35 may remain in the sixth region W6 .

[0111] M12: A sixth solvent is used to dissolve the portion of the third initial hole transport layer 153i located in the sixth region W6, and the portion of the blue initial quantum dot light-emitting layer 14Bi located in the sixth region W6 and away from the substrate 11 is removed. The portion of the third initial hole transport layer 153i located in the sixth region W6 and close to the substrate 11 is retained to form a third initial residual pattern 36, and the third hole transport layer 153 and quantum dot light-emitting layer 14B of the blue light-emitting device B are obtained.

[0112] In some examples, the light emitting substrate 10 further includes a pixel defining layer 12 , and a third initial residual pattern 36 is formed on a side of the pixel defining layer 12 away from the substrate 11 .

[0113] It should be understood that when removing the portion of the third initial hole transport layer 153i located in the sixth region W6 and away from the substrate 11, the third temporary residual layer 35 is also removed, which can effectively prevent the blue quantum dot luminescent material from remaining in the sixth region W6.

[0114] As can be seen from the above preparation process, in a light-emitting substrate prepared using a photolithographic sacrificial layer process, the material of the functional layer corresponding to the auxiliary sacrificial layer is a cross-linked material. For example, as shown in Figure 4, in a light-emitting substrate 10, the first hole transport layer 151 is an auxiliary sacrificial layer for the quantum dot light-emitting layer 14R, and the material of the first hole transport layer 151 is a first cross-linked hole transport material; the second hole transport layer 152 is an auxiliary sacrificial layer for the quantum dot light-emitting layer 14G, and the material of the second hole transport layer 152 is a second cross-linked hole transport material; the third hole transport layer 153 is an auxiliary sacrificial layer for the quantum dot light-emitting layer 14B, and the material of the third hole transport layer 153 is a third cross-linked hole transport material.

[0115] In some implementations, when the functional layer is made of a cross-linked material, the current density of the light-emitting device can be reduced, leading to a decrease in the efficiency of the light-emitting device. Therefore, to further enhance the production and application of the photolithography process for sacrificial layers, a reversible cross-linking strategy is needed to improve the efficiency of light-emitting devices produced using this photolithography process.

[0116] In order to more clearly illustrate the above problem, the following experimental example is used to illustrate the influence of a cross-linked material on the efficiency of a light-emitting device when the material of the functional layer is a cross-linked material.

[0117] The first group of test cases

[0118] In the following embodiments 1 to 3, as shown in FIG5 , the light emitting device 20 includes an anode 16 , a hole injection layer 18 , a hole transport layer 15 , a quantum dot light emitting layer 14 , an electron transport layer 19 and a cathode 17 stacked in sequence.

[0119] In the following Examples 1 to 3, the material of the anode 16 is indium tin oxide (ITO) with a thickness of about 100 nm; the material of the hole injection layer 18 is poly(3,4-ethylenedioxythiophene) (PEDOT) with a thickness of about 40 nm; the material of the hole transport layer 15 includes 1,2,4,5-tetrakis(trifluoromethyl)benzene (TFB) and a photosensitive crosslinker (the structure is shown in the following formula (CL)), and the mass ratio of the two is 95:5. The thickness of the hole transport layer 15 is about 30 nm; the material of the quantum dot light-emitting layer 14 is red quantum dot material CdSe / ZnS (material without photosensitive crosslinking function) with a thickness of about 30 nm; the material of the electron transport layer 19 is ZnMgO with a thickness of about 50 nm; the material of the cathode 17 is Al with a thickness of about 150 nm.

[0120] It should be noted that, as used in the description of the thickness of each film layer (e.g., the thickness of the anode 16) in the above embodiments, "about" includes the stated value as well as an average value within an acceptable deviation range of a specific value (e.g., 100 nm), wherein the acceptable deviation range is, for example, ±10% to ±15%. The same applies hereinafter.

[0121] In the following Examples 1 to 3, the preparation processes and conditions of the other film layers except the hole transport layer 15 and the quantum dot light emitting layer 14 are the same. The preparation processes of the hole transport layer 15 and the quantum dot light emitting layer 14 of Examples 1 to 3 are described below.

[0122] In Example 1, the preparation process of the hole transport layer 15 is a solution coating method without exposure treatment; the preparation process of the quantum dot light-emitting layer 14 is a solution coating method without exposure treatment.

[0123] In Example 2, the hole transport layer 15 is prepared by solution coating and subjected to high-pressure mercury lamp ultraviolet exposure (hereinafter referred to as UV-HT) treatment; the quantum dot light-emitting layer 14 is prepared by solution coating without exposure treatment.

[0124] In Example 3, the preparation process of the hole transport layer 15 is a solution coating method, and it is treated with high-pressure mercury lamp ultraviolet exposure (hereinafter referred to as UV-HT); the preparation process of the quantum dot light-emitting layer 14 is a solution coating method, and it is treated with high-pressure mercury lamp ultraviolet exposure (hereinafter referred to as UV-QD).

[0125] The external quantum efficiency (EQE) of the light-emitting devices in Examples 1 to 3 was measured, and the results are shown in FIG6 .

[0126] Comparing Example 1 with Example 2, as shown in Figure 6 , the external quantum efficiency of the light-emitting device decreased from 25.6% ± 1% to 22% ± 1% after UV-HT treatment, a decrease of approximately 3%, or 14%. Comparing Example 1 with Example 3, as shown in Figure 6 , the external quantum efficiency of the light-emitting device decreased from 25.6% ± 1% to 15.8% ± 0.6% after both UV-HT and UV-QD treatments, a decrease of approximately 10%, or 38%. This is because in Example 2, after UV-HT treatment, the TFB and photosensitive crosslinker in the hole transport layer undergo a crosslinking reaction, forming a crosslinked hole transport material. In Example 3, in addition to UV-HT treatment, the UV-QD treatment also occurs. Because the quantum dot light-emitting layer does not fully absorb photons, some photons pass through the quantum dot light-emitting layer and enter the hole transport layer, further crosslinking the TFB and photosensitive crosslinker in the hole transport layer, generating more crosslinked hole transport material. When the amount of crosslinked hole transport material in the hole transport layer is high, the hole transport rate of the light-emitting device decreases. Therefore, in both Example 2 and Example 3, the external quantum efficiency of the light-emitting device is reduced. Moreover, compared with Example 2, the reduction in the external quantum efficiency of the light-emitting device in Example 3 is greater.

[0127] The second group of test cases

[0128] In the following Examples 4 to 6, as shown in FIG7 , a hole-only device 40 (HOD device) includes an anode 16 , a hole injection layer 18A, a hole transport layer 15A, a quantum dot light-emitting layer 14 , a hole transport layer 15B, a hole injection layer 18B and a cathode 17 stacked in sequence.

[0129] In the following Examples 4 to 6, the material of the anode 16 is ITO, with a thickness of about 100 nm; the material of the hole injection layer 18A is PEDOT, with a thickness of about 40 nm; the material of the hole transport layer 15A includes TFB and a photosensitive crosslinker (the structure is shown in the above formula (CL)), and the mass ratio of the two is 95:5, and the thickness of the hole transport layer 15A is about 30 nm; the material of the quantum dot light-emitting layer 14 is red quantum dot material CdSe / ZnS (material without photosensitive crosslinking function), with a thickness of about 30 nm; the material of the hole transport layer 15B is a small molecule hole transport material 4,4',4"-tri(carbazole-9-yl)triphenylamine (TCTA) that can be evaporated, with a thickness of about 40 nm; the material of the hole injection layer 18B is MoOx, with a thickness of about 15 nm; the material of the cathode 17 is Al, with a thickness of about 150 nm.

[0130] In the following Examples 4 to 6, the preparation processes and conditions of the other film layers except the hole transport layer 15A and the quantum dot light-emitting layer 14 are the same. Among them, the preparation process of the hole transport layer 15A and the quantum dot light-emitting layer 14 in Example 4 is the same as the preparation process of the hole transport layer 15 and the quantum dot light-emitting layer 14 in Example 1; the preparation process of the hole transport layer 15A and the quantum dot light-emitting layer 14 in Example 5 is the same as the preparation process of the hole transport layer 15 and the quantum dot light-emitting layer 14 in Example 2; and the preparation process of the hole transport layer 15A and the quantum dot light-emitting layer 14 in Example 6 is the same as the preparation process of the hole transport layer 15 and the quantum dot light-emitting layer 14 in Example 3.

[0131] It should be understood that Example 4 can be used as the HOD device corresponding to Example 1, Example 5 can be used as the HOD device corresponding to Example 2, and Example 6 can be used as the HOD device corresponding to Example 3.

[0132] The hole current density of the HOD devices in Examples 4 to 6 was measured, and the obtained hole current density (unit: mA / cm 2 ) versus voltage (unit: V) is shown in FIG8 .

[0133] Comparing Example 4, Example 5, and Example 6, see Figure 8. Under the same voltage, the hole current density of the HOD device 40 is as follows from large to small: Example 4, Example 5, and Example 6. This is because in Examples 5 and 6, after UV-HT treatment, the TFB and the photosensitive crosslinker in the hole transport layer 15A undergo a cross-linking reaction to generate a cross-linked hole transport material. Moreover, in Example 6, in addition to the UV-HT treatment, it is also treated with UV-QD, which further cross-links the TFB and the photosensitive crosslinker in the hole transport layer 15A to generate more cross-linked hole transport material. When the cross-linked hole transport material in the hole transport layer 15A is high, the hole transport rate of the HOD device 40 will decrease. Therefore, in Examples 5 and 6, the hole current density of the HOD device 40 is reduced, and the reduction in the hole current density of the HOD device 40 in Example 6 is greater than that in Example 5.

[0134] The third group of test cases

[0135] Embodiment 7 is provided. In embodiment 7, the structure of the light emitting device 20 is the same as that of the light emitting device in embodiments 1 to 3, as shown in FIG5 .

[0136] In Example 7, the material and thickness of the anode 16, the material and thickness of the hole injection layer 18, the thickness of the hole transport layer 15, the material and thickness of the quantum dot light-emitting layer 14, the material and thickness of the electron transport layer 19, and the material and thickness of the cathode 17 are the same as those of Examples 1 to 3. Unlike Examples 1 to 3, the material of the hole transport layer 15 is TFB, and no photosensitive crosslinker is included.

[0137] In Example 7, the preparation processes and conditions of the other film layers except the hole transport layer 15 and the quantum dot light-emitting layer 14 are the same as those of Examples 1 to 3.

[0138] In Example 7, the preparation process of the hole transport layer 15 is a solution coating method, and it is treated with high-pressure mercury lamp ultraviolet exposure (hereinafter referred to as UV-HT); the preparation process of the quantum dot light-emitting layer 14 is a solution coating method, and it is treated with high-pressure mercury lamp ultraviolet exposure (hereinafter referred to as UV-QD).

[0139] The current density (unit: mA / cm 2 ) versus voltage (unit: V) is shown in FIG9 .

[0140] Comparing Examples 1-3 with Example 7, as shown in Figure 9, at the same voltage, the current density of the light-emitting device 20 is ranked from highest to lowest as follows: Example 7, Example 1, Example 2, and Example 3. This is because in Examples 2 and 3, after UV-HT treatment and UV-QD treatment, cross-linked hole transport material is generated. Moreover, compared to Example 2, there is more cross-linked hole transport material in Example 3. In contrast, in Example 1, the hole transport layer 15 contains a photosensitive crosslinker but is not subjected to UV-HT or UV-QD treatment, so no cross-linked hole transport material is generated. In Example 7, the hole transport layer 15 does not contain a photosensitive crosslinker, and even after UV-HT and UV-QD treatment, no cross-linked hole transport material is generated. The current density of Examples 1 and 7 is both relatively high, indicating that when the hole transport layer 15 does not contain a photosensitive crosslinker, even if the light-emitting device 20 is exposed normally according to the exposure process, the current density can be restored to the current density level of the uncross-linked light-emitting device 20 (i.e., Example 1).

[0141] It can be seen from the first to third test examples that when the material of the functional layer is a cross-linked material, the current density of the light-emitting device will be reduced, causing the efficiency of the light-emitting device to be attenuated.

[0142] Based on this, some embodiments of the present disclosure provide a functional layer forming material. The functional layer forming material includes a functional material and a cross-linking material. Wherein, the ratio between the mass of the cross-linking material and the mass of the functional material is greater than 0 and less than or equal to 15%. The cross-linking material is configured to: under a first preset condition, react with the functional material to generate a cross-linked functional material. In the cross-linked functional material, the segment corresponding to the functional material is the first segment, and the segment corresponding to the cross-linking material is the second segment. Under the second preset condition, the cross-linked functional material can undergo a decomposition reaction; in the decomposition reaction, the position where the cross-linked functional material decomposes is located at the connection between the first segment and the second segment, or at the middle of the second segment.

[0143] It should be understood that the functional material is a material among the above-mentioned functional layer forming materials that can realize the function of the functional layer, such as any one or a combination of carrier transport, carrier injection, and carrier blocking. The carriers are, for example, holes or electrons.

[0144] In some examples, as shown in FIG10 , the functional material is a hole transport functional layer material, such as any one of the materials for hole transport layer 15, hole injection layer 18, and electron blocking layer 51. In other examples, the functional material is an electron transport functional layer material, such as any one of the materials for electron transport layer 19, electron injection layer 53, and hole blocking layer 52. In other words, there is no limitation on the type of functional material, as long as the functional material is an organic material and can react with the cross-linking material to form a cross-linked functional material.

[0145] Here, the ratio of the mass of the cross-linking material to the mass of the functional material is greater than 0 and less than or equal to 15%. This arrangement can reduce the amount of cross-linking material in the functional layer forming material, reduce the impact of the cross-linking material on the performance of the functional material, and achieve a performance level close to that of the functional material.

[0146] For example, the functional material is a hole transport material, and the cross-linked functional material is a cross-linked hole transport material. When the ratio of the mass of the cross-linked material to the mass of the hole transport material is greater than 0 and less than or equal to 15%, compared to the case where the ratio of the mass of the cross-linked material to the mass of the hole transport material is greater than 15%, on the one hand, the stacking manner of the cross-linked hole transport material molecules after film formation is closer to the stacking manner of the hole transport material molecules after film formation, and on the other hand, the energy level of the cross-linked hole transport material is closer to the energy level of the hole transport material. In this way, the hole transport capability of the cross-linked hole transport material can be made closer to the hole transport capability of the hole transport material.

[0147] Exemplarily, the ratio of the mass of the cross-linking material to the mass of the functional material is greater than 0.2% and less than or equal to 10%.

[0148] Exemplarily, the ratio of the mass of the cross-linking material to the mass of the functional material is greater than 0.2% and less than or equal to 5%.

[0149] Exemplarily, the ratio of the mass of the cross-linking material to the mass of the functional material is greater than or equal to 0.2% and less than or equal to 1%.

[0150] Illustratively, the ratio of the mass of the cross-linked material to the mass of the functional material can be 0.2%, 0.5%, 0.8%, 1.0%, 1.5%, 2.5%, 3.5%, 4.2%, 5.0%, 8%, 10%, 13% or 15%, etc.

[0151] It should be noted that the ratio of the mass of the cross-linking material to the mass of the functional material in the functional layer-forming material can be calculated by separately measuring the mass of the functional material and the mass of the cross-linking material in the functional layer-forming material. The testing means and measurement methods for the mass of the functional material and the mass of the cross-linking material in the functional layer-forming material are not limited herein.

[0152] In some examples, the mass of the functional material in the functional layer forming material and the mass of the cross-linked material can be measured by H Nuclear Magnetic Resonance Spectra (HNMR) or C Nuclear Magnetic Resonance Spectra (CNMR), for example, by calculating the peak area of ​​the characteristic peak of the functional material to obtain the mass of the functional material, and by calculating the peak area of ​​the characteristic peak of the cross-linked material to obtain the mass of the cross-linked material.

[0153] In other examples, the mass of the functional material in the functional layer forming material and the mass of the cross-linked material can be measured by high performance liquid chromatography (HPLC), for example, the mass of the functional material is obtained by calculating the peak area of ​​the characteristic peak of the functional material, and the mass of the cross-linked material is obtained by calculating the peak area of ​​the characteristic peak of the cross-linked material.

[0154] For example, when the cross-linking material and the functional material can react to generate a cross-linked functional material; and the cross-linked functional material can undergo a decomposition reaction, the method for preparing the functional layer may include:

[0155] R1: Under the first preset condition, the cross-linking material and the functional material can react to form a cross-linked functional material. Moreover, the molecular structure of the cross-linked functional material includes a first segment corresponding to the functional material and a second segment corresponding to the cross-linking material.

[0156] R2: Under the second preset condition, the cross-linked functional material undergoes a decomposition reaction.

[0157] It should be understood that in R1, the reaction between the cross-linking material and the functional material is a cross-linking reaction. Since the cross-linking reaction occurs with a certain degree of randomness, the number of first segments or the number of second segments in a cross-linked functional material can be one or more. In other words, the number of first segments or the number of second segments in a cross-linked functional material is not limited herein.

[0158] In R2, the crosslinked functional material can decompose at at least three locations: the middle of the first segment; the junction of the first and second segments; and the middle of the second segment. In this context, all locations within the second segment, excluding the end structures, are considered to be within the middle of the second segment.

[0159] Understandably, when the cross-linked functional material decomposes at the middle of the first segment, the first segment corresponding to the functional material in the resulting functional layer is disconnected, potentially adversely affecting the functionality of the functional layer. Therefore, by arranging the cross-linked functional material decomposes at the junction of the first and second segments, or at the middle of the second segment, the functional layer retains the structure of the first segment and / or the functional material, maintaining a high level of performance and improving the electrical performance and efficiency of the light-emitting substrate.

[0160] In some examples, the cross-linked functional material includes a plurality of first segments and a plurality of second segments. In the decomposition reaction, the location where the cross-linked functional material decomposes is located at the connection between the first segment and the second segment. In this case, the cross-linked material and the functional material undergo a cross-linking reaction to generate the cross-linked functional material, and the process of the cross-linked functional material undergoing a decomposition reaction can be shown as follows (1).

[0161] In other examples, the cross-linked functional material includes multiple first segments and multiple second segments. During the decomposition reaction, the location where the cross-linked functional material decomposes is located in the middle of the second segment. In this case, the cross-linking material and the functional material undergo a cross-linking reaction to generate the cross-linked functional material, and the process of the cross-linked functional material undergoing a decomposition reaction can be shown as follows (2).

[0162] It should be noted that in formula (1) and formula (2), It represents the cross-linkable group (also known as the cross-linking site) of the functional material, that is, the part that reacts with the first group of the cross-linking material.

[0163] It can be understood that because the cross-linking material can react with the functional material under a first preset condition to form a cross-linked functional material, and the functional cross-linking material can undergo a decomposition reaction under a second preset condition, the cross-linking material can serve as a reversible cross-linker for the functional material. When a light-emitting substrate is prepared using a photolithographic sacrificial layer, the functional layer can serve as a front film layer for the quantum dot light-emitting layer. After the necessary development process is completed, step R2 is performed to decompose at least part of the cross-linked functional material by applying the second preset condition to achieve cross-link removal. In this way, compared to a case where the cross-linked functional material does not decompose, the material of the formed functional layer can contain relatively less cross-linked functional material.

[0164] In this case, when the prepared light-emitting substrate is working normally (for example, electroluminescence), the material of the functional layer can be in a non-cross-linked (or de-cross-linked) state. Compared with the case where the cross-linked functional material has not decomposed, the function of the functional layer (for example, the carrier transport function, the carrier injection function or the carrier blocking function) is less affected by the changes in electrical properties (for example, energy level, carrier transport rate or carrier injection rate) caused by cross-linking, so that the current density and efficiency of the light-emitting device are higher, the efficiency attenuation of the light-emitting device is less, and the electrical performance of the light-emitting device can be made to reach a level consistent with or closer to that of the light-emitting substrate in the non-cross-linked state, which can improve the electrical performance and efficiency of the light-emitting substrate prepared by the photolithography process using a photolithography sacrificial layer.

[0165] Moreover, the time for executing step R2 can be flexibly controlled, as long as it is completed after the necessary development process (for example, after the quantum dot light-emitting layers of each light-emitting device are developed), which can improve the feasibility of functional layer formation and light-emitting device preparation.

[0166] In some examples, as shown in formula (1) and formula (2), the cross-linked functional material undergoes a high degree of decrosslinking during the decomposition reaction. In other examples, the cross-linked functional material undergoes a relatively low degree of decrosslinking during the decomposition reaction, which can also be understood as partial decrosslinking of the cross-linked functional material. The following describes an example of partial decrosslinking of the cross-linked functional material.

[0167] In some embodiments, the cross-linked functional material comprises a plurality of first segments and a plurality of second segments. If, during a decomposition reaction, the cross-linked functional material decomposes at the junction of the first segment and the second segment, a portion of the first segment remains connected to a portion of the second segment after the decomposition reaction. If, during a decomposition reaction, the cross-linked functional material decomposes at the middle of the second segment, a portion of the second segment remains undecomposed after the decomposition reaction.

[0168] It should be understood that when a portion of the first segment remains connected to a portion of the second segment, or when a portion of the second segment has not decomposed, the material of the functional layer includes both cross-linked functional materials and products after decomposition reactions of the cross-linked functional materials (hereinafter referred to as de-crosslinked products). Moreover, compared with the cross-linked functional materials, the performance of the de-crosslinked products (such as hole transport performance) is at a higher level.

[0169] Understandably, when more cross-linked functional material undergoes decomposition, the degree of de-crosslinking of the cross-linked functional material is higher, and in this case, the performance of the functional layer (e.g., hole transport performance) is at a higher level. Therefore, when a portion of the first segment remains connected to a portion of the second segment, or when a portion of the second segment does not decompose, by regulating the proportion of the cross-linked functional material undergoing decomposition, the performance of the functional layer (e.g., carrier transport, carrier injection, or carrier blocking) can be regulated, thereby achieving regulation of the carrier transport, injection, or blocking performance of the light-emitting device.

[0170] For example, the proportion of the cross-linked functional material undergoing the decomposition reaction may be regulated by controlling the time and intensity of the decomposition reaction within a certain range.

[0171] The above exemplifies the cross-linking reaction between the functional material and the cross-linking material, as well as the reaction position and reaction degree of the decomposition reaction of the cross-linked functional material. The following exemplifies some possible implementation methods of the cross-linking reaction between the functional material and the cross-linking material, as well as the decomposition reaction of the cross-linked functional material.

[0172] In some examples, the cross-linking reaction between the cross-linking material and the functional material to generate the cross-linked functional material, and the decomposition reaction of the cross-linked functional material are shown in the above formula (1). As a possible implementation method, the functional material can be modified so that the functional material has a set group, and the set group can undergo a cross-linking reaction with the cross-linking material under a first preset condition to generate a cross-linked functional material. The cross-linked functional material can undergo a decomposition reaction under a second preset condition to regenerate the cross-linking material and the functional material.

[0173] Exemplarily, the setting group is a photosensitive group, the first preset condition includes irradiating a fourth light, the second preset condition includes irradiating a fifth light, and the wavelength band of the fourth light does not overlap with the wavelength band of the fifth light.

[0174] Exemplarily, the set group is a thermosensitive group, the first preset condition includes heating to a first reaction temperature, the second preset condition includes heating to a second reaction temperature, the first reaction temperature is different from the second reaction temperature, for example, the second reaction temperature is greater than the first reaction temperature.

[0175] In other examples, the cross-linking material and the functional material undergo a cross-linking reaction to generate a cross-linked functional material; and the cross-linked functional material undergoes a decomposition reaction, as shown in formula (2) above. Some embodiments of this case will be exemplarily introduced below.

[0176] In some embodiments, as shown in formula (2), the cross-linked material includes a plurality of first groups and at least one second group. The plurality of first groups are located at the ends of the cross-linked material and can react with the functional material under a first predetermined condition. The at least one second group is located in the middle of the cross-linked material and can decompose under a second predetermined condition.

[0177] It can be understood that based on the above structure, on the one hand, the crosslinking material can react with the functional material using the first group. Moreover, when the crosslinking material includes multiple first groups, a single crosslinking material molecule can react with multiple functional material molecules, achieving the purpose of crosslinking. On the other hand, when the crosslinking material includes at least one second group, the second segment corresponding to the crosslinking material also includes at least one second group. In this way, the at least one second group can cause the crosslinked functional material containing the second segment to undergo a decomposition reaction. Because the second group is located in the middle of the second segment, the crosslinked functional material decomposes at the middle of the second segment.

[0178] In some examples, the cross-linking material includes one second group. In this case, as shown in formula (2), when a decomposition reaction occurs, the second segment can be decomposed into two sub-segments, and the two sub-segments can be respectively connected to the two first segments. In another example, the cross-linking material includes multiple second groups. In this case, when a decomposition reaction occurs, the second segment can be decomposed into at least three sub-segments. When the second segment is a linear segment, the two sub-segments at the ends of the at least three sub-segments can be respectively connected to the two first segments; when the second segment is a branched segment, the at least three sub-segments can be connected to at least three first segments.

[0179] In the above embodiment, there is no limitation on the type of the first preset condition and the type of reaction between the cross-linking material and the functional material, as long as the requirement of generating a cross-linked functional material is met.

[0180] For example, if the first group is a second thermosensitive group and the first preset condition includes applying a heating means, the functional layer forming material can be heated to cause the functional material to react with the cross-linking material to generate a cross-linked functional material.

[0181] In some embodiments, the first group is a first photosensitive group, and the first preset condition includes irradiating a first light.

[0182] Here, the first group is a first photosensitive group, which means that the first group is a photosensitive reactive group / functional group, and is at least configured to react with the functional material under light conditions of a specific wavelength or wavelength band.

[0183] It is understood that through the above arrangement, upon irradiation with the first light, the functional material and the cross-linking material can react to form a cross-linked functional material. This can, firstly, match the reaction conditions for forming the cross-linked functional material with the preparation process for the quantum dot light-emitting substrate in some embodiments of the present disclosure (e.g., steps M1-M2, M5-M6, or M9-M10 in the aforementioned preparation method), thereby improving the feasibility of forming the cross-linked functional material; and secondly, it can facilitate the application of the first preset condition.

[0184] In some examples, the first preset condition is irradiation with a first light, such as ultraviolet light. In other examples, in addition to irradiation with the first light, the first preset condition also includes one or more of the following: introduction of an inert gas and addition of a certain reaction aid. In other words, the conditions other than irradiation with the first light in the first preset condition are not limited herein.

[0185] In some embodiments, the plurality of first groups are the same or different and are independently selected from any one of a benzophenone group, an azide group, a diazo group, and a diazirine group.

[0186] It can be understood that the benzophenone group, the azide group, the diazo group and the diazirine group are all photosensitive groups. When the first group is selected from any one of the benzophenone group, the azide group, the diazo group and the diazirine group, the first group can be used to make the functional material and the cross-linking material undergo a cross-linking reaction under the condition of irradiating the first light to generate a cross-linked functional material, so that the reaction conditions for generating the cross-linked functional material are easy to apply and match the preparation process of the quantum dot light-emitting substrate in some embodiments.

[0187] In some embodiments, the cross-linking material and the functional material undergo a carbon-hydrogen insertion reaction to generate a cross-linked functional material.

[0188] Understandably, since the functional materials are organic materials and mostly contain carbon-hydrogen bonds, the feasibility of generating cross-linked functional materials can be improved by setting up a carbon-hydrogen insertion reaction between the cross-linking material and the functional material, thereby increasing the number of functional materials available for selection.

[0189] In some examples, the first group is a first photosensitive group, the first photosensitive group is a benzophenone group, and the structure of the crosslinked material can be shown in Formula (3). The crosslinked material and the functional material undergo a carbon-hydrogen insertion reaction, and the carbon-hydrogen insertion reaction can be shown in Formula (4).

[0190] It should be noted that formula (3) shows a benzophenone group in the cross-linked material molecule, and formula (4) shows the reaction between the benzophenone group and the functional material molecule. It should be understood that, as described above, the cross-linked material molecule also includes at least one first group present in Ra, and the first group is, for example, any one of a benzophenone group, an azide group, a diazo group, and a diazirine group. Here, regarding the types of other first groups other than the benzophenone group shown in formula (3), and other structures other than the first group in Ra (for example, the second group described in detail below, and the structure of the molecular skeleton), there is no limitation here. Wherein, in the case where the other first groups other than the benzophenone group shown in formula (3) are not benzophenone groups, regarding the reaction between the first group and the functional material molecule, reference can be made to the reaction described in detail below, which will not be repeated here.

[0191] In some examples, the first group is a first photosensitive group, the first photosensitive group is an azide group, and the structure of the crosslinked material can be shown in Formula (5). The crosslinked material and the functional material undergo a carbon-hydrogen insertion reaction, and the carbon-hydrogen insertion reaction can be shown in Formula (6).

[0192] Formula (5) shows an azide group in the cross-linked material molecule, and formula (6) shows the reaction between the azide group and the functional material molecule. It should be understood that, as described above, the cross-linked material molecule also includes at least one first group present in Rb, and the first group is, for example, any one of a benzophenone group, an azide group, a diazo group, and a diazirine group. Here, regarding the types of other first groups other than the azide group shown in formula (5), the types of substituents X1, X2, X3, and X4, and other structures in Rb other than the first group (for example, the second group described in detail below, and the structure of the molecular skeleton), there is no limitation here. Wherein, in the case where the other first groups other than the azide group shown in formula (5) are not azide groups, regarding the reaction between the first group and the functional material molecule, reference can be made to the reaction described in detail above or below, and no further details will be given here.

[0193] In some examples, the first group is a first photosensitive group, the first photosensitive group is a diazo group, and the structure of the crosslinked material can be shown in Formula (7). The crosslinked material and the functional material undergo a carbon-hydrogen insertion reaction, and the carbon-hydrogen insertion reaction can be shown in Formula (8).

[0194] Formula (7) shows a diazo group in the cross-linked material molecule, and formula (8) shows the reaction between the diazo group and the functional material molecule. It should be understood that, as described above, the cross-linked material molecule also includes at least one first group present in Rc and / or Rd, the first group being, for example, any one of a benzophenone group, an azide group, a diazo group, and a diazirine group. Here, regarding the types of other first groups other than the diazo group shown in formula (7), and other structures other than the first group in Rc and Rd (for example, the second group described in detail below, and the structure of the molecular skeleton), there is no limitation here. Wherein, in the case where other first groups other than the diazo group shown in formula (7) are not diazo groups, regarding the reaction between the first group and the functional material molecule, reference can be made to the reaction described above or in detail below, which will not be repeated here.

[0195] In some examples, the first group is a first photosensitive group, the first photosensitive group is a diazirine group, and the structure of the crosslinked material can be shown in Formula (9). The crosslinked material and the functional material can undergo a carbon-hydrogen insertion reaction, and the carbon-hydrogen insertion reaction can be shown in Formula (10).

[0196] Formula (9) shows a diazirine group in the cross-linked material molecule, and formula (10) shows the reaction between the diazirine group and the functional material molecule. It should be understood that, as described above, the cross-linked material molecule also includes at least one first group present in Re and / or Rf, the first group being, for example, any one of a benzophenone group, an azide group, a diazo group, and a diazirine group. Here, regarding the types of other first groups except the diazirine group shown in formula (9), and other structures in Re and Rf except the first group (for example, the second group described in detail below, and the structure of the molecular skeleton), there is no limitation here. Wherein, in the case where other first groups except the diazirine group shown in formula (9) are not diazirine groups, regarding the reaction between the first group and the functional material molecule, regarding the reaction that can be referred to in the foregoing or detailed description below, no further details will be given here.

[0197] It should be noted that the above-listed structural formulas are examples of the structure of the cross-linked material and the carbon-hydrogen insertion reaction between the cross-linked material and the functional material, and are not intended to limit the structure of the cross-linked material and the carbon-hydrogen insertion reaction between the cross-linked material and the functional material. Moreover, (x) in the above structural formula is a synonym for each structure or reaction formula, and is not a part of the structure or reaction formula. Where x is a positive integer; the reaction condition UV represents ultraviolet light irradiation. Represents other structures in functional materials except the carbon-hydrogen bond part.

[0198] In some embodiments, the cross-linking material reacts with the functional material to generate a cross-linked functional material.

[0199] It is understood that when the functional material includes an unsaturated segment in its chain segment, the functional material includes an unsaturated bond such as an alkenyl, alkenylene, alkynyl, or alkynylene group. By configuring the crosslinking material to undergo an addition reaction with the functional material, the functional material and the crosslinking material can react to form a crosslinked functional material, thereby improving the feasibility of forming the crosslinked functional material and making the crosslinked material suitable for use with functional materials including unsaturated segments.

[0200] In some examples, the first group is a benzophenone group, and the structure of the cross-linked material can be as shown in Formula (3). In this case, the cross-linked material and the functional material undergo an addition reaction, and the addition reaction can be shown in Formula (11) or Formula (12).

[0201] In some examples, the first group is an azide group, and the structure of the cross-linking material can be as shown in Formula (4). In this case, the cross-linking material and the functional material undergo an addition reaction, and the addition reaction can be shown in Formula (13) or Formula (14).

[0202] In some examples, the first group is a diazo group, and the structure of the cross-linked material can be as shown in Formula (5). In this case, the cross-linked material and the functional material undergo an addition reaction, and the addition reaction can be shown in Formula (15) or Formula (16).

[0203] In some examples, the first group is a diazirine group, and the structure of the cross-linked material can be as shown in Formula (6). In this case, the cross-linked material and the functional material undergo an addition reaction, and the addition reaction can be shown in Formula (17) or Formula (18).

[0204] It should be noted that Formula (11), Formula (13), Formula (15) and Formula (17) show the reaction between the functional material and the cross-linking material when the alkenyl group of the functional material is located in the middle of the molecular chain of the functional material and at the end of the molecular chain of the functional material. In practical applications, the alkenyl group of the functional material can be located only in the middle of the molecular chain of the functional material, or only at the end of the molecular chain of the functional material, or a part of the alkenyl group can be located in the middle of the molecular chain of the functional material and another part of the alkenyl group can be located at the end of the molecular chain of the functional material, and this is not limited here. Moreover, when the alkenyl group of the functional material is located only in the middle of the molecular chain of the functional material and only at the end of the molecular chain of the functional material, the addition reaction between the functional material and the cross-linking material can be referred to Formula (11), Formula (13), Formula (15) and Formula (17), which will not be repeated here.

[0205] It should be noted that the above-listed structural formulas are examples of addition reactions between crosslinking materials and functional materials, and do not limit the structure of the crosslinking materials or the addition reactions between the crosslinking materials and functional materials. Moreover, (x) in the above structural formulas is a synonym for each structure or reaction formula, and is not a part of the structure or reaction formula. Where x is a positive integer; the reaction condition UV represents ultraviolet light irradiation. Represents other structures in functional materials except the unsaturated bond part.

[0206] The above is an exemplary description of the first group and the reaction between the first group and the functional material when the crosslinking material includes the first group. The following is an exemplary description of the decomposition reaction of the second group and the crosslinked functional material when the crosslinking material includes the second group.

[0207] In some embodiments, the second group is a second photosensitive group, and the second preset condition includes irradiating a second light. When the first group is a first photosensitive group, the second light is different from the first light.

[0208] Here, the second group is a second photosensitive group, which means that the second group is a photosensitive cleavable group / functional group or a bond-breaking group / functional group, and is at least configured to undergo a cleavage reaction or a bond-breaking reaction under light conditions of a specific wavelength or band.

[0209] Here, the second light is different from the first light, which means that the wavelength or wavelength band of the first light does not overlap with the wavelength or wavelength band of the second light. For example, the wavelength of the first light is a first wavelength value, and the wavelength of the second light is a second wavelength value. The first wavelength value and the second wavelength value are different, and there is a certain difference between the first wavelength value and the second wavelength value.

[0210] As can be understood, through the above arrangement, irradiation with the second light can cause the crosslinked functional material to undergo a decomposition reaction. The decomposition of the crosslinked functional material occurs in the middle of the second segment, making it easier to apply the second preset condition. Furthermore, if the first group is a first photosensitive group, the configuration of the second light being different from the first light can reduce the impact of the second preset condition on any functional material and crosslinking material that may be present in the functional layer.

[0211] In some examples, the second preset condition is irradiation with a second light, such as ultraviolet light. In other examples, in addition to irradiation with the second light, the second preset condition also includes one or more of the following: introduction of an inert gas and addition of a certain reaction aid. In other words, the second preset condition other than irradiation with the second light is not limited herein.

[0212] In some examples, the functional layer is formed of a hole transport layer, and a quantum dot light-emitting layer is disposed on one side of the hole transport layer. The material forming the quantum dot light-emitting layer forms a quantum dot light-emitting layer under the action of a third light (for example, the material of the quantum dot light-emitting layer includes a cross-linked quantum dot light-emitting material). In this case, the second light and the third light may be the same or different, and this is not a limitation.

[0213] In some embodiments, the second group is a structure represented by the following formula (IA-1).

[0214] Wherein, * is the first connection site.

[0215] It should be understood that the second group can be connected to other structures in the cross-linking material molecule through the first connection site, such as the second connection site # described in detail below.

[0216] In some examples, under the second preset condition (i.e., irradiation with the second light), the decomposition reaction of the second group represented by the structure of Formula (IA-1) can be as follows: Formula (19).

[0217] For example, the UV in formula (19) can be mixed ultraviolet light of 250 nm to 400 nm, or ultraviolet light of a specific wavelength (for example, 254 nm or 365 nm).

[0218] It should be noted that formula (19) illustrates the main products in the reaction, and some small molecule products that may be generated in the reaction are not shown in formula (19).

[0219] It can be understood that when the second group is a structure represented by formula (IA-1), the second group is a second photosensitive group. Thus, upon irradiation with the second light, the second segment of the cross-linked functional material molecule can be decomposed (e.g., decomposed into at least two sub-segments), so that the location where the cross-linked functional material decomposes is located in the middle of the second segment. For example, as shown in formula (19), the connection between one of the first linking sites and the product represented by formula (19) is disconnected, thereby achieving the purpose of decomposing the second segment.

[0220] In some embodiments, the second group is a first thermosensitive group, and the second preset condition includes applying heating means.

[0221] Here, the second group is the first thermosensitive group, which means that the second group is a thermosensitive cleavable group / functional group or a bond-scissile group / functional group, and is at least configured to undergo a cleavage reaction or a bond-scissile reaction under heating conditions.

[0222] Understandably, through the above arrangement, heating the crosslinked functional material to a predetermined temperature can cause the crosslinked functional material to undergo a decomposition reaction, with the decomposition occurring in the middle of the second segment. This facilitates the application of the second predetermined condition and allows the decomposition reaction of the crosslinked functional material to be completed during the thermal annealing process after the completion of other functional layers, or during the thermal annealing of the entire device after fabrication. This eliminates the need for adding new steps to achieve decomposition of the crosslinked functional material, improving process feasibility.

[0223] In some examples, the second preset condition is heating to a set temperature and maintaining it at the set temperature for a set time. In other examples, in addition to heating to a set temperature and maintaining it at the set temperature for a set time, the second preset condition also includes one or more of the following: protection from light, passage of an inert gas, and addition of a certain reaction aid. In other words, the second preset condition other than heating is not limited herein.

[0224] In some embodiments, when the cross-linking material includes one second group, the second group is any one of an azo group, a peroxide group, a persulfide group, an acetyl ketone group, and a methylthiophenol group. When the cross-linking material includes multiple second groups, the multiple second groups are the same or different and are independently selected from any one of an azo group, a peroxide group, a persulfide group, an acetyl ketone group, and a methylthiophenol group.

[0225] It can be understood that the azo group, peroxide group, persulfide group, acetyl ketone group and methylthiophenol group are all thermosensitive groups, which can undergo a decomposition reaction (such as a bond breaking reaction or a cleavage reaction) under the second preset condition (including heating conditions), so that the second segment of the cross-linked functional material molecule can be decomposed (for example, decomposed into at least two sub-segments), so that the location where the cross-linked functional material decomposes is located in the middle of the second segment.

[0226] In some embodiments, when the second group is an azo group, the second group has a structure represented by the following general formula (IA-2).

[0227] Wherein, * is the first connection site.

[0228] R1, R2, R3 and R4 are the same or different and are independently selected from any one of hydrogen, C1-C40 substituted or unsubstituted saturated or unsaturated straight or branched alkyl, C1-C40 substituted or unsubstituted ester, C1-C40 substituted or unsubstituted nitrile, C3-C40 substituted or unsubstituted cycloalkyl, 3-40 membered substituted or unsubstituted heterocyclic group, C6-C40 substituted or unsubstituted aryl and 5-40 membered substituted or unsubstituted heteroaryl, or may be connected with adjacent groups to form a substituted or unsubstituted 3-40 membered ring.

[0229] Here, for the description of the first linking site, reference may be made to the description of the first linking site in formula (IA-1), which will not be repeated here.

[0230] Wherein, the straight-chain alkyl of Cx refers to a straight-chain alkyl group having x carbon (C) atoms, where x is a positive integer, and the same shall apply. For understandings of other groups such as branched-chain alkyl of Cx and ester groups of Cx, reference may be made to the above content and will not be repeated here. Furthermore, phenyl refers to the general term for the group remaining after the hydrogen atom of a carbon atom on the benzene ring is removed. For understandings of other groups such as aryl, heteroaryl, ester groups, etc., reference may be made to the above content and will not be repeated here. Furthermore, a Z-membered heteroaryl refers to a heteroaryl group having Z atoms on the ring, where Z is a positive integer, and the same shall apply. For understandings of other groups such as Z-membered heterocyclic groups and Z-membered rings, reference may be made to the above content and will not be repeated here.

[0231] When R1, R2, R3 or R4 is selected from any one of a C1-C40 substituted saturated or unsaturated linear or branched alkyl group, a C1-C40 substituted ester group, a C1-C40 substituted nitrile group, a C3-C40 substituted cycloalkyl group, a 3-membered to 40-membered substituted heterocyclic group, a C6-C40 substituted aryl group and a 5-membered to 40-membered substituted heteroaryl group, the type and number of the substituents are not limited herein.

[0232] It can be understood that the structure shown in general formula (IA-2) contains an azo group, which can undergo a decomposition reaction (such as a bond breaking reaction or a cleavage reaction) under the action of the second preset condition, causing the cross-linked functional material to decompose, and the location where the decomposition occurs is located in the middle of the second segment.

[0233] In some embodiments, R1 and R4 are the same and are selected from any one of the structures represented by the following formulae (IA-2-1) to (IA-2-7).

[0234] wherein a, b and c are the same or different and are independently selected from any one of 0, 1, 2 and 3.

[0235] It can be understood that when R1 and R4 are selected from any one of the structures shown in the following general formulas (IA-2-1) to (IA-2-7), the molecular weight of the second group is low, which can make the molecular weight of the cross-linked material lower. First, it can reduce the steric effect when the cross-linked material and the functional material undergo cross-linking reaction. Second, it can make the molar amount of the cross-linked material in the functional layer forming material larger, thereby improving the cross-linking function of the cross-linked material.

[0236] In some embodiments, R2 and R3 are the same and are selected from any one of the structures shown in the following formulas (IA-2-8) to (IA-2-16).

[0237] wherein d and e are the same or different and are independently selected from any one of 0, 1, 2, 3, 4, 5 and 6.

[0238] It can be understood that, similarly to the above, when R2 and R3 are selected from any one of the structures shown in the following general formulas (IA-2-1) to (IA-2-7), the molecular weight of the second group is relatively low, which can reduce the steric hindrance effect when the cross-linking material and the functional material undergo cross-linking reaction, and at the same time, the cross-linking function of the cross-linking material can be improved.

[0239] For example, when R1 and R4 are the same, and R2 and R3 are the same, the decomposition reaction of the second group can be as shown in formula (20).

[0240] Here, R2' is the remaining structure after removing a hydrogen atom from R2.

[0241] For example, when the first group is an azide group, the second group is an azo group, and the azo group is selected from one of the structures shown in the general formula (IA-2), the cross-linking reaction between the cross-linking material and the functional material, and the decomposition reaction of the cross-linked functional material can be as shown in formula (23).

[0242] It should be understood that when the cross-linked functional material in formula (23) undergoes a decomposition reaction, product 1 and product 2 may be generated, or two products 3 may be generated.

[0243] For example, when the first group is a benzophenone group, the second group is an azo group, and the azo group is selected from one of the structures shown in the general formula (IA-2), the cross-linking reaction between the cross-linking material and the functional material, and the decomposition reaction of the cross-linked functional material can be as shown in formula (24).

[0244] It should be understood that when the cross-linked functional material in formula (24) undergoes a decomposition reaction, product 4 and product 5 may be generated, or two products 6 may be generated.

[0245] It should be noted that in formula (23) and formula (24), Represents functional material molecules, and the same applies below.

[0246] In some embodiments, when the second group is a peroxide group, the second group is selected from any one of the structures represented by the following formulae (IA-3) to (IA-8).

[0247] Wherein, * is the first connection site.

[0248] f, g, h and i are the same or different and are independently selected from any one of 0, 1, 2, 3, 4, 5 and 6.

[0249] Here, for the description of the first linking site, reference may be made to the description of the first linking site in formula (IA-1), which will not be repeated here.

[0250] It can be understood that the structures shown in general formulas (IA-3) to (IA-8) all contain peroxide groups, which can undergo a decomposition reaction (such as a bond breaking reaction or a cleavage reaction) under the action of the second preset condition, causing the cross-linked functional material to decompose, and the location where the decomposition occurs is located in the middle of the second chain segment.

[0251] For example, when the second group is a structure represented by formula (IA-3), the decomposition reaction of the second group can be as represented by formula (21).

[0252] For example, when the second group is a structure represented by formula (IA-5), the decomposition reaction of the second group can be as represented by formula (22).

[0253] It should be noted that formula (22) illustrates the main structure of the second group, and some of the carbon-hydrogen structures in the second group are not shown in formula (22).

[0254] For example, when the first group is a benzophenone group, the second group is an azo group, and the azo group is selected from one of the structures shown in the general formula (IA-2), the cross-linking reaction between the cross-linking material and the functional material, and the decomposition reaction of the cross-linked functional material can be as shown in formula (25).

[0255] It should be understood that when the cross-linked functional material in formula (25) undergoes a decomposition reaction, product 7 or product 8 may be generated.

[0256] In some embodiments, when the second group is a persulfate group, the second group is selected from any one of the structures shown in the following formulas (IA-9) to (IA-14);

[0257] Wherein, * is the first connection site.

[0258] j, k, m and n are the same or different and are independently selected from any one of 0, 1, 2, 3, 4, 5 and 6.

[0259] Here, for the description of the first linking site, reference may be made to the description of the first linking site in formula (IA-1), which will not be repeated here.

[0260] It can be understood that the structures represented by general formulas (IA-9) to (IA-14) all contain persulfide groups, which can undergo a decomposition reaction (such as a bond breaking reaction or a cleavage reaction) under the action of the second preset condition, causing the cross-linked functional material to decompose, and the location where the decomposition occurs is located in the middle of the second segment.

[0261] In some embodiments, when the second group is an acetyl ketone group, the second group is a structure as shown in the following formula (IA-15);

[0262] Wherein, * is the first connection site.

[0263] Here, for the description of the first linking site, reference may be made to the description of the first linking site in formula (IA-1), which will not be repeated here.

[0264] It is understandable that the acetyl ketone group can undergo a decomposition reaction (such as a bond breaking reaction or a cleavage reaction) under the second preset condition, causing the cross-linked functional material to decompose, and the decomposition location is located in the middle of the second segment.

[0265] In some embodiments, when the second group is a methylthiophenol group, the second group has a structure represented by the following general formula (IA-16).

[0266] Wherein, * is the first connection site.

[0267] Here, for the description of the first linking site, reference may be made to the description of the first linking site in formula (IA-1), which will not be repeated here.

[0268] It is understandable that the methylthiophenol group can undergo a decomposition reaction (such as a bond breaking reaction or a cracking reaction) under the action of the second preset condition, causing the cross-linked functional material to decompose, and the decomposition location is located in the middle of the second segment.

[0269] In some embodiments, the cross-linking material is selected from any one of the structures represented by the following formula (I) and formula (II).

[0270] G is selected from any one of the structures represented by the following general formula (IB).

[0271] Wherein, J is the first group; # is the second connection site.

[0272] A is a second group; if the second group includes a first attachment site, the first attachment site is connected to the second attachment site. L1, L2, and L3 are the same or different and are independently selected from any one of a C1-C40 substituted or unsubstituted amide group, a C1-C40 substituted or unsubstituted ester group, a C1-C40 substituted or unsubstituted saturated or unsaturated linear or branched alkyl group, a C3-C40 substituted or unsubstituted cycloalkyl group, a 3-40 membered substituted or unsubstituted heterocyclic group, a C6-C40 substituted or unsubstituted aryl group, and a 5-40 membered substituted or unsubstituted heteroaryl group. E1 and E2 are the same or different and are independently selected from carbon, oxygen, sulfur, selenium, sulfur, phosphorus, a C1-C40 substituted or unsubstituted saturated or unsaturated linear or branched alkyl group, a C3-C40 substituted or unsubstituted cycloalkyl group, a 3- to 40-membered substituted or unsubstituted heterocyclic group, a C6-C40 substituted or unsubstituted aryl group, and a 5- to 40-membered substituted or unsubstituted heteroaryl group. x, y, and w are the same or different and are independently selected from 1, 2, 3, 4, 5, and 6. z is selected from 2, 3, 4, 5, and 6.

[0273] Here, E1 and E2 in the general formula (IB) can be understood as molecular skeletons (such as atoms or molecular chains), and the w first groups J are connected to the molecular skeleton E2 through w L3 respectively, and the w L3 can be the same or different.

[0274] The general formula (I) is a case where the cross-linking material contains a second group A. In the general formula (I), x Gs are contained, which means that x molecular skeletons E2 are connected to the second group A through x L2s, and the x L2s can be the same or different.

[0275] General formula (II) is a case where the cross-linked material contains multiple (i.e., z) second groups A, and the z second groups A are respectively connected to E1 through z L1. In general formula (II), y Gs are connected to the second group A, which means that y molecular skeletons E2 are respectively connected to the second group A through y L2, and the y L2s can be the same or different. Here, among the z second groups A, the number of E2 connected to each second group A (i.e., y) can be the same or different.

[0276] The description of the amide group of Cx, the ester group of Cx, etc. here can refer to the above description of the straight-chain alkyl group of Cx; the description of the Z-membered heteroaryl group, the Z-membered heterocyclic group, etc. here can refer to the above description of the Z-membered heteroaryl group; they will not be repeated here.

[0277] It should be noted that when L1, L2 or L3 is selected from any one of a C1-C40 substituted amide group, a C1-C40 substituted ester group, a C1-C40 substituted saturated or unsaturated linear or branched alkyl group, a C3-C40 substituted cycloalkyl group, a 3-40 membered substituted heterocyclic group, a C6-C40 substituted aryl group and a 5-40 membered substituted heteroaryl group, and / or E is selected from any one of a C1-C40 substituted saturated or unsaturated linear or branched alkyl group, a C3-C40 substituted cycloalkyl group, a 3-40 membered substituted heterocyclic group, a C6-C40 substituted aryl group and a 5-40 membered substituted heteroaryl group, the type and number of the substituents are not limited herein.

[0278] It can be understood that when the cross-linking material is selected from any one of the structures shown in general formula (I) and general formula (II), the cross-linking material includes multiple first groups and at least one second group. In this way, using the first group, the cross-linking material can react with the functional material to achieve the purpose of cross-linking; using the second group, the cross-linking functional material can undergo a decomposition reaction, and the position where the cross-linking functional material decomposes is located in the middle of the second segment.

[0279] Moreover, when w is not 1, multiple first groups J are connected to the same E2, and the multiple first groups J can be connected to multiple functional material molecules. In this way, when the second group A undergoes a decomposition reaction, the multiple functional material molecules connected to the same E2 still maintain a connection relationship, so that when the cross-linked functional material decomposes, the degree of de-crosslinking is relatively low. In this way, the performance of the functional layer (for example, carrier transport, carrier injection function or carrier blocking function) can be regulated to achieve the regulation of the carrier transport, injection or blocking performance of the light-emitting device.

[0280] For example, when the cross-linking material is one of the structures represented by general formula (I), x is 2, and both w are 1, the structural formula of the cross-linking material can be represented by the following formula.

[0281] For example, when the cross-linking material is one of the structures represented by general formula (I), x is 3, and all three ws are 1, the structural formula of the cross-linking material can be represented by the following formula.

[0282] For example, when the cross-linking material is one of the structures represented by general formula (I), x is 2, and the two ws are 1 and 2 respectively, the structural formula of the cross-linking material can be represented by the following formula.

[0283] For example, when the cross-linking material is one of the structures represented by general formula (I), x is 4, and all four ws are 1, the structural formula of the cross-linking material can be represented by the following formula.

[0284] For example, when the cross-linking material is one of the structures represented by general formula (I), x is 3, and the three ws are 1, 1, and 2, respectively, the structural formula of the cross-linking material can be represented by the following formula.

[0285] For example, when the cross-linking material is one of the structures represented by general formula (I), x is 2, and the two ws are 1 and 3 respectively, the structural formula of the cross-linking material can be represented by the following formula.

[0286] Illustratively, when the cross-linking material is one of the structures represented by general formula (II), z is 2, two y's are all 2, and four w's are all 1, the structural formula of the cross-linking material can be represented by the following formula.

[0287] Illustratively, when the cross-linked material is one of the structures represented by general formula (II), z is 2, two ys are both 3, and six ws are 1, 1, 2, 1, 1, and 1, respectively, the structural formula of the cross-linked material can be represented by the following formula.

[0288] It should be noted that the structural formula listed above is an example of the connection method between the first group A and the second group J in the cross-linking material, and is not a limitation on the connection method between the first group A and the second group J in the cross-linking material.

[0289] In some embodiments, L1, L2, and L3 are the same or different and are independently selected from any one of the structures represented by the following general formulas (IC-1) to (IC-3);

[0290] wherein R5 and R6 are the same or different and are independently selected from any one of a C1-C40 substituted or unsubstituted saturated or unsaturated straight-chain or branched alkyl group, a C1-C40 substituted or unsubstituted nitrile group, a C3-C40 substituted or unsubstituted cycloalkyl group, a 3-membered to 40-membered substituted or unsubstituted heterocyclic group, a C6-C40 substituted or unsubstituted aryl group, and a 5-membered to 40-membered substituted or unsubstituted heteroaryl group; and at least one of R5 and R6 is a C1-C6 substituted or unsubstituted saturated straight-chain or branched alkyl group.

[0291] The description of the branched alkyl group of Cx, the cycloalkyl group of Cx, etc. here can refer to the above description of the straight-chain alkyl group of Cx; the description of the Z-membered heteroaryl group, the Z-membered heterocyclic group, etc. here can refer to the above description of the Z-membered heteroaryl group; they will not be repeated here.

[0292] It should be noted that when R5 and R6 are selected from any one of a C1-C40 substituted saturated or unsaturated straight-chain or branched alkyl group, a C3-C40 substituted cycloalkyl group, a 3-membered to 40-membered substituted heterocyclic group, a C6-C40 substituted aryl group, and a 5-membered to 40-membered substituted heteroaryl group, the type and number of the substituents are not limited here.

[0293] Illustratively, R5 and R6 are the same or different, and are independently selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, and nitrile.

[0294] Illustratively, at least one of R5 and R6 is selected from any one of the following formulae (IC-a-1) to (IC-a-9).

[0295] Wherein, ** represents the connection site with the adjacent group.

[0296] It can be understood that when L1, L2 or L3 is one of the structures shown in the general formula (IC-1), the structures located on both sides of L1, L2 or L3 can be connected through an amide reaction; when L1, L2 or L3 is one of the structures shown in the general formula (IC-2), the structures located on both sides of L1, L2 or L3 can be connected through an esterification reaction; when L1, L2 or L3 is one of the structures shown in the general formula (IC-3), the structures located on both sides of L1, L2 or L3 can be connected through a click reaction between azide-alkyne groups; in this way, the synthetic feasibility of the cross-linked material can be improved.

[0297] Moreover, when at least one of R5 and R6 is a C1-C6 substituted or unsubstituted saturated linear or branched alkyl group, the cross-linking material can be synthesized more easily, thereby improving the feasibility of synthesizing the cross-linking material.

[0298] In some embodiments, E1 and E2 are the same or different and are independently selected from any one of the structures represented by the following general formulas (ID-1) to (ID-6).

[0299] wherein L is L1, L2 or L3. p, r and s are the same or different and are independently selected from any one of 1, 2, 3, 4, 5 and 6.

[0300] It should be understood that when E1 or E2 is selected from any of the structures represented by general formulas (ID-1) and (ID-4), E1 or E2 is a linear molecular skeleton; when E1 or E2 is selected from any of the structures represented by general formulas (ID-2), (ID-3), (ID-5), and (ID-6), E1 or E2 is a branched molecular skeleton. Among them, (ID-2) and (ID-5) are two-branched branched molecular skeletons, and (ID-3) and (ID-6) are three-branched branched molecular skeletons.

[0301] When E1 or E2 is selected from any one of the structures shown in general formulas (ID-1) to (ID-3), E1 or E2 is an alkane chain-type molecular skeleton; when E1 or E2 is selected from any one of the structures shown in general formulas (ID-4) to (ID-6), E1 or E2 is a PEO chain-type molecular skeleton.

[0302] It is understood that when E1 or E2 is an alkane chain molecular backbone or a PEO chain molecular backbone, the cross-linked material can be easily prepared. Furthermore, when E1 is a branched molecular backbone, multiple second groups can be attached to one E1; and when E2 is a branched molecular backbone, multiple first groups can be attached to one E2, thereby allowing the number of first groups and / or second groups contained in the cross-linked material to be controlled.

[0303] In some embodiments, E1 and E2 are the same or different and are independently selected from a PEG chain or a polyether chain. There is no limitation on the structure of the PEG chain or the polyether chain and the number of repeating units.

[0304] On the other hand, some embodiments of the present disclosure provide a method for preparing a functional layer. As shown in FIG11 , the method for preparing a functional layer includes steps N1 to N3.

[0305] N1: providing a functional layer forming material; the functional layer forming material includes: a functional material and a cross-linking material; the ratio between the mass of the cross-linking material and the mass of the functional material is greater than 0 and less than or equal to 15%.

[0306] N2: Under the first preset condition, the cross-linking material and the functional material react to generate a cross-linked functional material; in the cross-linked functional material, the segment corresponding to the functional material is the first segment, and the segment corresponding to the cross-linking material is the second segment.

[0307] N3: Under the second preset condition, the cross-linked functional material undergoes a decomposition reaction to form a functional layer; in the decomposition reaction, the cross-linked functional material decomposes at a location where the first segment and the second segment are connected, or at a middle portion of the second segment.

[0308] The beneficial effects that can be achieved by a functional layer preparation method provided by some embodiments of the present disclosure are the same as the beneficial effects that can be achieved by a functional layer forming material provided by the above technical solution, and will not be repeated here.

[0309] In some embodiments, the first preset condition is an exposure condition. When the functional layer is formed, the quantum dot light-emitting layer is also formed.

[0310] The functional layer preparation method specifically includes: forming a first initial functional layer, wherein the material of the first initial functional layer includes a functional layer forming material; exposing the first initial functional layer, wherein the exposed portion of the first initial functional layer forms a second initial functional layer, wherein the material of the second initial functional layer includes a cross-linked functional material; developing the unexposed portion of the first initial functional layer; and causing the cross-linked functional material in the second initial functional layer to undergo a decomposition reaction under a second preset condition.

[0311] A method for preparing a quantum dot light-emitting layer includes forming an initial quantum dot light-emitting layer, exposing the initial quantum dot light-emitting layer, and developing the initial quantum dot light-emitting layer.

[0312] Among them, developing the unexposed portion of the first initial functional layer and developing the initial quantum dot light-emitting layer are performed after exposing the first initial functional layer and before causing the cross-linked functional material in the second initial functional layer to undergo a decomposition reaction under second preset conditions.

[0313] It can be understood that through the above-mentioned setting, the functional layer can serve as an auxiliary sacrificial layer of the quantum dot light-emitting layer, and the material forming the quantum dot light-emitting layer (for example, quantum dot light-emitting material) is partially removed in the remaining areas except the area where the target opening is located, which can solve the color mixing problem caused by the residual layer formed by the quantum dot light-emitting material.

[0314] The following describes the preparation methods of the functional layer and the quantum dot light-emitting layer by taking the functional layer as an example of a hole transport layer.

[0315] Illustratively, as shown in FIG12 , the method of forming the hole transport layer and the quantum dot light-emitting layer includes steps H1 to H6.

[0316] H1: A first initial hole transport layer 15iA is formed on the side of the front film layer 13B away from the substrate 11. The materials of the first initial hole transport layer 15iA include: a hole transport material and a cross-linking material. The front film layer 13B is, for example, an anode or a hole injection layer.

[0317] Here, for exemplary descriptions of the hole transport material and the cross-linking material, please refer to the aforementioned content and will not be repeated here.

[0318] H2: Form an initial quantum dot light-emitting layer 14i on the side of the first initial hole transport layer 15iA away from the substrate 11. The material of the initial quantum dot light-emitting layer 14i includes, for example, a quantum dot light-emitting material and a photosensitive material. Expose the target area W7.

[0319] Illustratively, the quantum dot light-emitting material includes a quantum dot body and a ligand material coordinated to the quantum dot body.

[0320] In some examples, the target area W7 is exposed in H2, so that the quantum dot luminescent material and the photosensitive material in the target area W7 react to generate a cross-linked quantum dot luminescent material, and at the same time, the hole transport material and the cross-linking material in the target area W7 react to generate a cross-linked hole transport material (i.e., a cross-linked functional material), forming a second initial hole transport layer 15iB.

[0321] In other examples, H1 further includes: exposing the target area W7 so that the hole transport material and the cross-linking material in the target area W7 react to generate a cross-linked hole transport material (i.e., a cross-linked functional material) to form the second initial hole transport layer 15iB. In this case, exposing the target area W7 in H2 causes the quantum dot luminescent material and the photosensitive material in the target area W7 to react to generate a cross-linked quantum dot luminescent material.

[0322] Among them, in the cross-linked hole transport material, the segment corresponding to the hole transport material is the first segment, and the segment corresponding to the cross-linked material is the second segment.

[0323] Illustratively, during the exposure process, a mask plate or a mask layer may be used to expose the target area W7.

[0324] In this case, before step H3 , the mask plate or the mask layer is removed.

[0325] H3: using a seventh solvent to dissolve the portion of the initial quantum dot light-emitting layer 14i located in the eighth region W8, thereby removing the portion of the initial quantum dot light-emitting layer 14i located in the eighth region W8, wherein the eighth region W8 is the remaining region except the target region W7.

[0326] Exemplarily, the quantum dot luminescent material and the photosensitive material may remain in the portion close to the substrate 11 , and a temporary residual layer 37 may remain in the eighth region W8 .

[0327] H4: The portion of the first initial hole transport layer 15iA located in the eighth region W8 is dissolved using an eighth solvent. The portion of the first initial hole transport layer 15iA located in the eighth region W8 and away from the substrate 11 is removed, while the portion of the first initial hole transport layer 15iA located in the eighth region W8 and close to the substrate 11 is retained, forming an initial residual pattern 38. The quantum dot light-emitting layer 14 located in the target region W7 is obtained.

[0328] In some examples, the light emitting substrate 10 further includes a pixel defining layer 12 , and an initial residual pattern 38 is formed on a side of the pixel defining layer 12 away from the substrate 11 .

[0329] It should be understood that when removing the portion of the first initial hole transport layer 15iA located in the eighth region W8 and away from the substrate 11, the temporary residual layer 37 is also removed, which can effectively prevent the quantum dot light-emitting material from remaining in the eighth region W8.

[0330] H5: forming other film layer structures located in the eighth region W8.

[0331] For example, the method for forming other film layer structures located in the eighth region W8 may refer to steps M5 to M12 in the method for preparing the light-emitting substrate in the aforementioned section.

[0332] H6: Under the second preset condition, the cross-linked hole transport material of the second initial hole transport layer 15iB undergoes a decomposition reaction to form a hole transport layer; in the decomposition reaction, the position where the cross-linked hole transport material decomposes is located at the connection between the first segment and the second segment, or at the middle of the second segment.

[0333] In some examples, the other film structures located in the eighth region W8 include initial hole transport layers of other light-emitting devices (e.g., the second initial hole transport layer 152 and the third initial hole transport layer 153, as shown in FIG3 ), and the materials of these initial hole transport layers are cross-linked hole transport materials. In this case, under the second preset condition, in addition to the cross-linked hole transport material of the second initial hole transport layer 15iB, the cross-linked hole transport material located in the eighth region W8 also undergoes a decomposition reaction to form a hole transport layer located in the eighth region W8.

[0334] 10 , some embodiments of the present disclosure provide a light emitting device 20. The light emitting device 20 includes an anode 16, a cathode 17, and a functional layer located between the anode 16 and the cathode 17. The functional layer may be formed of a material as described in any of the above embodiments.

[0335] For example, in order to ensure that the light-emitting device 20 can effectively emit light, the anode 16 can be made of a material with a high work function, such as a material with a work function greater than 6 eV; the cathode 17 can be made of a material with a low work function, such as a material with a work function less than a set value, and the set value can range from 2.0 eV to 3.0 eV. In this way, the holes in the anode and the electrons in the cathode can effectively migrate to the light-emitting layer (for example, the quantum dot light-emitting layer 14) under the drive of the electric field, thereby compounding and emitting light.

[0336] In some examples, the material of the anode 16 may be a transparent conductive metal oxide material, for example, the material of the anode 16 may be indium tin oxide (ITO) or indium zinc oxide (IZO).

[0337] In some examples, the material of the cathode 17 may be a metal material. For example, the material of the cathode 12 may be magnesium, silver, aluminum, or a magnesium-silver alloy.

[0338] The beneficial effects that can be achieved by a light-emitting device provided by some embodiments of the present disclosure are the same as the beneficial effects that can be achieved by a functional layer forming material provided by the above technical solution, and will not be repeated here.

[0339] In some examples, the light emitting device 20 is a quantum dot light emitting device including a quantum dot light emitting layer 14 .

[0340] During operation, voltage is applied to the anode 16 and the cathode 17 respectively, so that an electric field is generated between the two, which can drive the holes in the anode 16 and the electrons in the cathode 17 to recombine in the quantum dot light-emitting layer 14, thereby emitting light.

[0341] Illustratively, the materials forming quantum dot light-emitting layer 14 include a quantum dot light-emitting material and a photosensitive material. The quantum dot light-emitting material includes a quantum dot body and a ligand material coordinated to the quantum dot body. The photosensitive material is configured to undergo a cross-linking reaction with the ligand material under light radiation conditions to produce a cross-linked quantum dot light-emitting material.

[0342] In some examples, the quantum dot body can include any combination of any one or more of: II-VI quantum dots, III-V quantum dots, IV-VI quantum dots, IV quantum dots, I-III-VI quantum dots, I-II-IV-VI quantum dots, core-shell structured quantum dots, and ABX3 type perovskite quantum dots.

[0343] II-VI quantum dots can be selected from: binary compounds such as one or more of CdS, CdSe, CdTe, ZnS, ZnO, ZnSe, ZnTe, HgSe, HgTe and HgS; ternary compounds such as Hg x Cd 1-x Te, Hg x Cd 1-x S, Hg x Cd 1- x Se, Hg x Zn 1-x Te, Cd x Zn 1-x Se, Cd x Zn 1-x One or more of S and ZnTeSe, wherein 0<x<1, but not limited thereto.

[0344] The III-V quantum dots may be selected from: InP, InAs, InSb, GaAs, GaP, GaN, GaSb, GaNk, InN, AlP, AlN, AlAs, InGaAs, InGaN, or a mixture thereof; but are not limited thereto.

[0345] The Group IV-VI quantum dots may be selected from: PbS, PbSe, PbTe, or a mixture thereof, but are not limited thereto.

[0346] Core-shell quantum dots refer to quantum dots in which one material is the core and the other is the shell. For example, a quantum dot is CdS@ZnS, which means that the core material of the quantum dot is CdS and the shell material is ZnS. The quantum dots with core-shell structures can be selected from: CdS@ZnS, CdSe@CdS, InP@ZnS, CdTe@CdSe, CdSe@ZnTe, CdSe@ZnS, PdS@ZnS, ZnTe@CdSe, ZnSe@CdS and Cd 1-x Zn xOne or more of S@ZnS, wherein 0<x<1, but not limited thereto.

[0347] In ABX3 type perovskite quantum dots, A can be CH3NH3 + (methylamine), NH2CH=NH2(formamidine) and Cs + One or more of, B can be Pb 2+ and Sn 2+ One or two of the following, X can be Cl - Br - and I - One or more of the ABX3 type perovskite quantum dots may include CH3NH3PbBr3, CH3NH3PbCl3, CH3NH3PbI3, CsPbBr3, CsPbCl3 and CsPbI3, but are not limited thereto.

[0348] When multiple quantum dots are combined, the quantum dot body can be one of CsPbCl3 / ZnS, CsPbBr3 / ZnS, CsPhI3 / ZnS, CdS / ZnSeS / ZnS, CdSe / ZnSeS / ZnS, ZnSe / ZnSeS / ZnS and ZnSeTe / ZnSeS / ZnS.

[0349] In other examples, the quantum dot body may be other nanoscale materials, such as nanorods, nanosheets, etc. Components of other nanoscale materials may include at least one of CuInS2, CuInSe2, AgInS2, etc., but are not limited thereto.

[0350] For example, the shape of the quantum dot body can be any geometric shape such as sphere, ellipsoid, polyhedron, rod, cross, ring, etc.

[0351] In some examples, the ligand material can be selected from any one or more combinations of organic acids, organic amines, organic phosphorus and organic thiols. For example, the ligand material can be oleic acid, oleylamine or dodecanethiol.

[0352] In some embodiments, as shown in FIG10 , to improve the luminous efficiency of the light-emitting device 20, the light-emitting device 20 further includes a hole transport functional layer, which is located on a side of the quantum dot light-emitting layer 14 close to the anode 16 and in contact with the quantum dot light-emitting layer 14. The hole transport functional layer includes, for example, at least one of a stacked hole injection layer 18 (HIL), a hole transport layer 15 (HTL), and an electron blocking layer 51 (EBL).

[0353] In some examples, when the hole transport functional layer includes the hole injection layer 18, the hole transport layer 15, and the electron blocking layer 51, the hole injection layer 18, the hole transport layer 15, and the electron blocking layer 51 are sequentially arranged in a direction away from the anode 16, and the electron blocking layer 51 is in contact with the quantum dot light-emitting layer 14. In other examples, when the hole transport functional layer includes the hole injection layer 18 and the hole transport layer 15, the hole injection layer 18 and the hole transport layer 15 are sequentially arranged in a direction away from the anode 16, and the hole transport layer 15 is in contact with the quantum dot light-emitting layer 14. In this case, the hole injection layer 18 is a front film layer when the hole transport layer 15 is formed.

[0354] In some embodiments, as shown in FIG10 , in order to improve the luminous efficiency of the light-emitting device 20, the light-emitting device 20 further includes an electron transport functional layer, which is located on the side of the quantum dot light-emitting layer 14 close to the cathode 12 and in contact with the quantum dot light-emitting layer 14. The electron transport functional layer, for example, includes at least one of a stacked electron injection layer 53 (Electron Inject Layer, EIL), an electron transport layer 19 (Electron Transport Layer, ETL), and a hole blocking layer 52 (Hole Blocking Layer, EBL). When the electron transport functional layer includes an electron injection layer 53, an electron transport layer 19, and a hole blocking layer 52, the electron injection layer 53, the electron transport layer 19, and the hole blocking layer 52 are arranged in sequence in a direction away from the cathode 12, and the hole blocking layer 52 is in contact with the quantum dot light-emitting layer 14.

[0355] By setting up the film layers such as the hole injection layer 18, the hole transport layer 15, the electron blocking layer 51, the electron injection layer 53, the electron transport layer 19 and the hole blocking layer 52, it is equivalent to setting up transition steps between the anode 16 and the quantum dot light-emitting layer 14, and between the cathode 12 and the quantum dot light-emitting layer 14, thereby reducing the potential barrier height that needs to be overcome for carrier transition, thereby making the luminescence efficiency higher.

[0356] Exemplarily, the hole transport functional layer is configured to transport holes and / or block electrons and excitons generated in the quantum dot light-emitting layer 14. For example, the hole injection layer 18 can be configured to lower the hole injection barrier and improve the hole injection efficiency. The hole transport layer 15 can be configured to transport holes. The electron blocking layer 51 can be configured to transport holes and block electrons and excitons generated in the quantum dot light-emitting layer 14.

[0357] Exemplarily, the electron transport functional layer is configured to transport electrons and / or block holes and excitons generated in the quantum dot light emitting layer 14 .

[0358] In some embodiments, as shown in FIG4 , when the plurality of light-emitting devices 20 include a red light-emitting device R, a green light-emitting device G, and a blue light-emitting device B, the cathodes 17 of the plurality of light-emitting devices 20 are structured to be interconnected throughout the entire layer, i.e., the cathode 12 can be a common electrode shared by the plurality of light-emitting devices 20. The hole injection layer 18 of the plurality of light-emitting devices 20 can also be structured to be interconnected throughout the entire layer, i.e., the hole injection layer 18 can be a common film layer shared by the plurality of light-emitting devices 20. The hole transport layer 15, the electron blocking layer 51, the electron injection layer 53, the electron transport layer 19, and the hole blocking layer 52 can also be common film layers shared by the plurality of light-emitting devices 20, and are not further described here.

[0359] For example, as shown in FIG. 4 , when the cathode 12 is a common electrode shared by a plurality of light-emitting devices 20 , the cathode 12 is simultaneously formed on a side of the pixel defining layer 12 away from the substrate 11 .

[0360] In some embodiments, the functional layer includes one or more of a quantum dot light-emitting layer 14 , a hole transport layer 15 , a hole injection layer 18 , an electron blocking layer 51 , an electron transport layer 19 , an electron injection layer 53 , and a hole blocking layer 52 .

[0361] In some examples, the functional layer includes one or more of the electron transport layer 19 , the electron injection layer 53 , and the hole blocking layer 52 . That is, the functional layer is located between the cathode 17 and the quantum dot light emitting layer 14 .

[0362] It can be understood that when the functional layer is located between the cathode 17 and the quantum dot light-emitting layer 14, the functional layer can serve as an auxiliary sacrificial layer of the quantum dot light-emitting layer. The material forming the quantum dot light-emitting layer 14 is removed from the remaining areas except the area where the target opening is located, which can solve the color mixing problem caused by the residual layer formed by the quantum dot light-emitting material.

[0363] In some embodiments, as shown in FIG. 10 , the functional layer is located between the anode 16 and the quantum dot light-emitting layer 14 .

[0364] It should be understood that when the functional layer is located between the anode 16 and the quantum dot light-emitting layer 14, the functional layer is any one of the hole injection layer 18, the hole transport layer 15, and the electron blocking layer 51, for example, the hole transport layer 15. In this way, the functional layer can serve as an auxiliary sacrificial layer for the quantum dot light-emitting layer, removing the portion of the material forming the quantum dot light-emitting layer 14 located in the area other than the area where the target opening is located, thereby solving the color mixing problem caused by the residual layer formed by the quantum dot light-emitting material.

[0365] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in the present disclosure should be included within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A functional layer forming material, comprising: Functional materials and crosslinking materials; wherein, the ratio of the mass of the crosslinking material to the mass of the functional material is greater than 0 and less than or equal to 15%; the crosslinking material is configured to react with the functional material under a first preset condition to generate a crosslinked functional material; In the crosslinked functional material, the segment corresponding to the functional material is the first segment, and the segment corresponding to the crosslinking material is the second segment; under a second preset condition, the crosslinked functional material can undergo a decomposition reaction; in the decomposition reaction, the position where the crosslinked functional material decomposes is at the junction of the first segment and the second segment, or in the middle of the second segment.

2. The functional layer forming material according to claim 1, wherein, The crosslinked functional material includes a plurality of the first segments and a plurality of the second segments; In the case where the position where the crosslinked functional material decomposes in the decomposition reaction is at the junction of the first segment and the second segment, after the decomposition reaction, a part of the first segment and a part of the second segment remain connected; In the case where the position where the crosslinked functional material decomposes in the decomposition reaction is in the middle of the second segment, after the decomposition reaction, a part of the second segment does not decompose.

3. The functional layer forming material according to claim 1 or 2, wherein, The crosslinking material includes: A plurality of first groups, located at the ends of the crosslinking material and capable of reacting with the functional material under the first preset condition; and, At least one second group, located in the middle of the crosslinking material and capable of decomposing under the second preset condition.

4. The functional layer forming material according to claim 3, wherein The first group is a first photosensitive group, and the first preset condition includes irradiating with a first light.

5. The functional layer forming material according to claim 3 or 4, wherein The plurality of first groups are the same or different and are each independently selected from any one of benzophenone group, azide group, diazo group and bisaziridine group.

6. The functional layer forming material according to any one of claims 1 to 5, wherein The crosslinking material and the functional material undergo a hydrocarbon insertion reaction or an addition reaction to generate the crosslinked functional material.

7. The functional layer forming material according to any one of claims 3 to 6, wherein, The second group is a second photosensitive group, and the second preset condition includes irradiating with a second light; In the case where the first group is a first photosensitive group, the second light is different from the first light.

8. The functional layer forming material according to claim 7, wherein, The second group has a structure represented by the following formula (IA-1); Wherein, * is the first connection site.

9. The functional layer forming material according to any one of claims 3 to 6, wherein The second group is a first thermosensitive group, and the second preset condition includes applying a heating means.

10. The functional layer forming material according to claim 9, wherein, In the case where the crosslinking material includes one second group, the second group is any one of azo group, peroxy group, persulfide group, acetyl ketone group and methylthiophenol group; In the case where the crosslinking material includes a plurality of the second groups, the plurality of second groups are the same or different and are each independently selected from any one of azo group, peroxy group, persulfide group, acetyl ketone group and methylthiophenol group.

11. The functional layer forming material according to claim 10, wherein, When the second group is an azo group, the second group has a structure represented by the following general formula (IA-2); Wherein, * is the first connection site; R1, R2, R3 and R4 are the same or different and are each independently selected from any one of hydrogen, a substituted or unsubstituted saturated or unsaturated straight-chain or branched alkyl group having 1 to 40 carbon atoms, a substituted or unsubstituted ester group having 1 to 40 carbon atoms, a substituted or unsubstituted nitrile group having 1 to 40 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 40 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 40 members, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, and a substituted or unsubstituted heteroaryl group having 5 to 40 members, or may be linked to an adjacent group to form a substituted or unsubstituted ring having 3 to 40 members.

12. The functional layer forming material according to claim 11, wherein, R1 and R4 are the same and are selected from any one of the structures represented by the following formulas (IA-2-1) to (IA-2-7); Among them, a, b and c are the same or different and are each independently selected from any one of 0, 1, 2 and 3.

13. The functional layer forming material according to claim 11 or 12, wherein, R2 and R3 are the same and are each selected from any one of the structures represented by the following formulas (IA-2-8) to (IA-2-16); Among them, d and e are the same or different and are each independently selected from any one of 0, 1, 2, 3, 4, 5 and 6.

14. The functional layer forming material according to claim 10, wherein, When the second group is a peroxy group, the second group is selected from any one of the structures represented by the following formulas (IA-3) to (IA-8); Among them, * is the first connection site; f, g, h and i are the same or different and are each independently selected from any one of 0, 1, 2, 3, 4, 5 and 6.

15. The functional layer forming material according to claim 10, wherein, When the second group is a persulfur group, the second group is selected from any one of the structures represented by the following formulas (IA-9) to (IA-14); Among them, * is the first connection site; j, k, m and n are the same or different and are each independently selected from any one of 0, 1, 2, 3, 4, 5 and 6.

16. The functional layer forming material according to claim 10, wherein, When the second group is an acetyl ketone group, the second group has the structure shown in the following formula (IA-15); Among them, * is the first connection site.

17. The functional layer forming material according to claim 10, wherein, When the second group is a methylthiophenol group, the second group has a structure represented by the following general formula (IA-16); Among them, * is the first connection site.

18. The functional layer forming material according to any one of claims 3 to 17, wherein, The crosslinked material is selected from any one of the structures represented by the following general formula (I) and general formula (II); G is selected from any one of the structures represented by the following general formula (IIB); Among them, J is the first group; # is the second connection site; A is the second group; when the second group includes the first connection site, the first connection site is connected to the second connection site; L1, L2 and L3 are the same or different and are each independently selected from any one of a substituted or unsubstituted amide group having 1 to 40 carbon atoms, a substituted or unsubstituted ester group having 1 to 40 carbon atoms, a substituted or unsubstituted saturated or unsaturated straight-chain or branched alkyl group having 1 to 40 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 40 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 40 members, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, and a substituted or unsubstituted heteroaryl group having 5 to 40 members; E1 and E2 are the same or different and are each independently selected from any one of carbon, oxygen, sulfur, selenium, sulfur, phosphorus, a substituted or unsubstituted saturated or unsaturated straight-chain or branched alkyl group having 1 to 40 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 40 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 40 members, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, and a substituted or unsubstituted heteroaryl group having 5 to 40 members; x, y and w are the same or different and are each independently selected from any one of 1, 2, 3, 4, 5 and 6. z is selected from any one of 2, 3, 4, 5 and 6.

19. The functional layer forming material according to claim 18, wherein, L1, L2, and L3 are the same or different and are each independently selected from any one of the structures represented by the following general formulas (IC-1) to (IC-3); Among them, R5 and R6 are the same or different and are each independently selected from any one of a saturated or unsaturated substituted or unsubstituted straight-chain or branched alkyl group having 1 to 40 carbon atoms, a substituted or unsubstituted nitrile group having 1 to 40 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 40 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 40 members, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, and a substituted or unsubstituted heteroaryl group having 5 to 40 members; moreover, among R5 and R6, at least one is a saturated substituted or unsubstituted straight-chain or branched alkyl group having 1 to 6 carbon atoms.

20. The functional layer forming material according to claim 18 or 19, wherein, E1 and E2 are the same or different and are each independently selected from any one of the structures represented by the following general formulas (ID-1) to (ID-6); Wherein, L is L1, L2 or L3; p, r and s are the same or different, and are each independently selected from any one of 1, 2, 3, 4, 5 and 6.

21. A method for preparing a functional layer, comprising: Providing a functional layer forming material; The functional layer forming material includes: a functional material and a crosslinking material; the ratio of the mass of the crosslinking material to the mass of the functional material is greater than 0 and less than or equal to 15%; Under a first preset condition, reacting the crosslinking material with the functional material to generate a crosslinked functional material; in the crosslinked functional material, the segment corresponding to the functional material is the first segment, and the segment corresponding to the crosslinking material is the second segment; Under a second preset condition, subjecting the crosslinked functional material to a decomposition reaction to form a functional layer; in the decomposition reaction, the position where the crosslinked functional material decomposes is at the connection between the first segment and the second segment, or in the middle of the second segment.

22. A light-emitting device, comprising an anode, a cathode, and a functional layer located between the anode and the cathode; the forming material of the functional layer includes the functional layer forming material according to any one of claims 1 to 20.

23. The light-emitting device according to claim 22, wherein, The functional layer includes one or more of a quantum dot light-emitting layer, a hole transport layer, a hole injection layer, an electron blocking layer, an electron transport layer, an electron injection layer, and a hole blocking layer.

24. The light-emitting device according to claim 23, wherein, The functional layer is located between the anode and the quantum dot light-emitting layer.

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