Cross-linking agent, quantum dot and composition thereof, quantum dot light-emitting layer and preparation method therefor, light-emitting apparatus, and display device

Abstract

Provided in the present disclosure are a cross-linking agent, a quantum dot, a quantum dot composition, a quantum dot light-emitting layer and a preparation method therefor, a light-emitting apparatus, and a display device. The cross-linking agent has a general formula of R-(R1)n, wherein R comprises at least three reaction sites linked with R1 and is selected from any one of the following groups in formula (I) and formula (II), with formula (I) representing a polymer chain, and the functional group of the polymer chain comprising at least one of a carboxyl, a hydroxyl and an aldehyde group; and R1 comprises an azide group N3, n is a positive integer greater than or equal to 3, and the numerical value of n is equal to the number of the reaction sites.

Description

Crosslinking agent, quantum dot and composition thereof, quantum dot luminescent layer and preparation method thereof, light-emitting device, and display device Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a cross-linking agent, quantum dots, a quantum dot composition, a quantum dot light-emitting layer, a light-emitting device, a display apparatus, and a method for preparing a patterned quantum dot light-emitting layer. Background Art

[0002] Light emitting diodes (LEDs) emit light by releasing energy through the recombination of electrons and holes. Light emitting diodes include but are not limited to organic light emitting diodes (OLEDs) and quantum dot light emitting diodes (QLEDs). Quantum dots are a type of semiconductor nanomaterial that can bind excitons in three-dimensional space. Due to their excellent properties such as high quantum efficiency, narrow excitation spectrum, high photostability, long fluorescence lifetime, and good solution processing compatibility, they have great application potential in high-quality displays. Quantum dot light emitting diodes are devices that use quantum dots as light-emitting materials. Compared with organic light emitting diodes, they have outstanding advantages such as lower energy consumption, higher color purity, and a wider color gamut. Therefore, quantum dot light emitting technology has become the most promising next-generation self-luminous display technology.

[0003] Summary of the Invention

[0004] According to one aspect of the present disclosure, there is provided a cross-linking agent having the general formula R-(R1): n , R includes at least three reactive sites connected to R1, and R is selected from any one of the following groups:

[0005] represents a polymer chain, the functional groups of the polymer chain include at least one of a carboxyl group, a hydroxyl group, and an aldehyde group, and R1 includes an azide group N3, n is a positive integer greater than or equal to 3, and the value of n is equal to the number of the reaction sites.

[0006] In some embodiments, the chemical formula of R1 is Any one of R2 to R6 is a conjugated group or a non-conjugated group, and the conjugated group or the non-conjugated group is connected to the reaction site on R, and the remaining groups of R2 to R6 except the group connected to the reaction site on R are the same as or different from each other and are respectively selected from fluorine atoms or hydrogen atoms.

[0007] In some embodiments, the non-conjugated group includes at least one of an ester group, an amide group, an ether group, an imine group, and a carbon-nitrogen double bond.

[0008] In some embodiments, the conjugated group includes a carbon-carbon double bond.

[0009] In some embodiments, the chemical formula of R1 is R4 is connected to the reactive site on the R.

[0010] In some embodiments, n is equal to 4, and the chemical formula of the cross-linking agent is

[0011] In some embodiments, the cross-linking agent is or, or, or, or,

[0012] According to another aspect of the present disclosure, a quantum dot is provided, comprising a quantum dot body and a ligand coordinated to the quantum dot body, wherein the ligand comprises a carbon-hydrogen bond and is configured to undergo a cross-linking reaction with the cross-linking agent described in any of the previous embodiments under light radiation.

[0013] In some embodiments, the ligand is selected from any one of oleylamine, isooctylthiol, thioglycolic acid, mercaptopropionic acid, oleic acid, and 2-mercaptoethyl Boc amine.

[0014] In some embodiments, the quantum dots are configured to emit red light or blue light, and the ligand is oleic acid.

[0015] In some embodiments, the quantum dots are configured to emit green light, and the ligand is 2-mercaptoethyl Boc amine.

[0016] According to another aspect of the present disclosure, a quantum dot composition is provided, comprising a mixed solution comprising the quantum dots described in any of the preceding embodiments, a cross-linking agent described in any of the preceding embodiments, and a solvent. The concentration of the quantum dots in the mixed solution is approximately 20 to 35 mg / mL, and the concentration of the cross-linking agent in the mixed solution is approximately 0.1 to 2.0 mg / mL.

[0017] In some embodiments, the solvent is selected from any one of propylene glycol methyl ether acetate, toluene, chlorobenzene, octane, water, and alcohol solvents.

[0018] According to another aspect of the present disclosure, a quantum dot light-emitting layer is provided, comprising a plurality of quantum dots. At least some of the plurality of quantum dots comprise a quantum dot body and ligands coordinated to the quantum dot body, and the quantum dot light-emitting layer is generated by cross-linking the quantum dots having the ligands and a cross-linking agent as described in any of the preceding embodiments.

[0019] In some embodiments, the chemical formula of the quantum dot light-emitting layer is R-(R1'-R7-QD) n , wherein QD represents a quantum dot, R7 represents the ligand and includes a carbon-hydrogen bond, and R1' represents a group obtained by replacing the azide group N3 of the group R1 with an NH group.

[0020] In some embodiments, the chemical formula of the quantum dot light-emitting layer is R4 is a conjugated group or a non-conjugated group, and R2, R3, R5, and R6 are the same as or different from each other and are independently selected from fluorine atoms or hydrogen atoms.

[0021] In some embodiments, the quantum dot light emitting layer is configured to emit red light or blue light, and the chemical formula of the quantum dot light emitting layer is R7 is oleic acid.

[0022] In some embodiments, the quantum dot light-emitting layer is configured to emit green light, and the chemical formula of the quantum dot light-emitting layer is R7 is 2-mercaptoethyl Boc amine.

[0023] In some embodiments, the quantum dot light-emitting layer includes multiple first quantum dot patterns, multiple second quantum dot patterns, multiple first sub-pixel areas, and multiple second sub-pixel areas. The first quantum dot patterns are configured to emit red light, and the second quantum dot patterns are configured to emit green light. The first quantum dot pattern is only located in the first sub-pixel area and not in the second sub-pixel area. The second quantum dot pattern is only located in the second sub-pixel area and not in the first sub-pixel area.

[0024] In some embodiments, the quantum dot light-emitting layer also includes multiple third quantum dot patterns and multiple third sub-pixel areas, the third quantum dot pattern is configured to emit blue light, the first quantum dot pattern is located only in the first sub-pixel area and not in the second sub-pixel area and the third sub-pixel area, the second quantum dot pattern is located only in the second sub-pixel area and not in the first sub-pixel area and the third sub-pixel area, and the third quantum dot pattern is located only in the third sub-pixel area and not in the first sub-pixel area and the second sub-pixel area.

[0025] According to another aspect of the present disclosure, a light-emitting device is provided, comprising: a first electrode layer; an electron transport layer located on the first electrode layer; the quantum dot light-emitting layer described in any of the previous embodiments, located on a side of the electron transport layer away from the first electrode layer; a hole transport layer located on a side of the quantum dot light-emitting layer away from the first electrode layer; and a second electrode layer located on a side of the hole transport layer away from the first electrode layer.

[0026] In some embodiments, the electron transport layer is a nanoparticle.

[0027] According to another aspect of the present disclosure, a display device is provided, comprising a plurality of light-emitting devices described in any one of the foregoing embodiments, wherein at least two of the plurality of light-emitting devices are configured to emit light of different colors.

[0028] According to another aspect of the present disclosure, a method for preparing a patterned quantum dot light-emitting layer is provided, comprising: providing a substrate; applying a mixed solution on the substrate, the mixed solution comprising quantum dots and a cross-linker, the quantum dots comprising a quantum dot body and a ligand coordinated to the quantum dot body, the ligand comprising a carbon-hydrogen bond, and the cross-linker being the cross-linker described in any of the previous embodiments; curing the mixed solution to form a cured layer; and exposing and developing the cured layer to form a patterned quantum dot light-emitting layer.

[0029] In some embodiments, the solidified layer is exposed and developed, including: exposing the solidified layer using a mask plate, allowing ultraviolet light to pass through the mask plate to expose the solidified layer, and under the ultraviolet light, the crosslinking agent reacts with the ligands on the surface of the quantum dots to undergo a cross-linking reaction; and developing the cross-linked solidified layer using a developer, wherein the portion of the solidified layer located in the non-exposed area is dissolved by the developer, and the portion of the solidified layer located in the exposed area is not dissolved by the developer, so as to form the patterned quantum dot light-emitting layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Hereinafter, various exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings; in the accompanying drawings:

[0031] FIG1 is a schematic diagram showing the patterning principle of a quantum dot light-emitting layer in the related art;

[0032] FIG2 shows an electroluminescent spectrum of the quantum dot light-emitting layer of FIG1 ;

[0033] FIG3 shows a schematic diagram of another patterning principle of a quantum dot light-emitting layer in the related art;

[0034] FIG4 shows a photograph of the quantum dot light-emitting layer of FIG3 after being patterned;

[0035] FIG5 shows some chemical formulas of groups R according to embodiments of the present disclosure;

[0036] FIG6 shows the general formula of the group R1 according to an embodiment of the present disclosure;

[0037] FIG7 shows a general formula of a cross-linking agent according to an embodiment of the present disclosure;

[0038] FIG8 shows the general formula of another cross-linking agent according to an embodiment of the present disclosure;

[0039] FIG9 shows a general formula of another cross-linking agent according to an embodiment of the present disclosure;

[0040] FIG10 shows the general formula of another cross-linking agent according to an embodiment of the present disclosure;

[0041] FIG11 shows the general formula of another cross-linking agent according to an embodiment of the present disclosure;

[0042] FIG12 shows the general formula of yet another cross-linking agent according to an embodiment of the present disclosure;

[0043] FIG13 shows the general formula of yet another cross-linking agent according to an embodiment of the present disclosure;

[0044] FIG14 shows the chemical formula of a cross-linking agent according to an embodiment of the present disclosure;

[0045] FIG15 shows the chemical formula of a cross-linking agent according to an embodiment of the present disclosure;

[0046] FIG16 shows a synthetic route of the cross-linking agent of FIG15 ;

[0047] FIG17 shows a hydrogen nuclear magnetic resonance spectrum of the cross-linking agent in FIG15 ;

[0048] FIG18 shows the chemical formula of another cross-linking agent according to an embodiment of the present disclosure;

[0049] FIG19 shows a synthetic route of the cross-linking agent of FIG18 ;

[0050] FIG20 shows the chemical formula of yet another cross-linking agent according to an embodiment of the present disclosure;

[0051] FIG21 shows a synthetic route of the cross-linking agent of FIG20 ;

[0052] FIG22 shows the chemical formula of yet another cross-linking agent according to an embodiment of the present disclosure;

[0053] FIG23 shows a synthetic route of the cross-linking agent of FIG22 ;

[0054] FIG24 shows the chemical formula of yet another cross-linking agent according to an embodiment of the present disclosure;

[0055] FIG25 shows a synthetic route of the cross-linking agent of FIG24 ;

[0056] FIG26 shows a schematic structural diagram of a quantum dot according to an embodiment of the present disclosure;

[0057] FIG27 shows a general formula of a quantum dot light-emitting layer after a cross-linking reaction between a cross-linking agent and quantum dots according to an embodiment of the present disclosure;

[0058] FIG28 shows the chemical formula of the quantum dot light-emitting layer after the cross-linking reaction between the cross-linking agent and the quantum dots according to an embodiment of the present disclosure;

[0059] FIG29 shows a synthesis route of the quantum dot light-emitting layer of FIG28 ;

[0060] FIG30 shows the luminescence patterns of the quantum dot luminescent layer of FIG28 under different development conditions;

[0061] FIG31 shows the electroluminescent spectra of the quantum dot light-emitting layer of FIG28 under different development conditions;

[0062] FIG32 shows a photograph of a patterned green quantum dot light-emitting layer;

[0063] FIG33 shows the chemical formula of the quantum dot light-emitting layer after the cross-linking reaction between the cross-linking agent and the quantum dots according to an embodiment of the present disclosure;

[0064] FIG34 shows a synthesis route of the quantum dot light-emitting layer of FIG33 ;

[0065] FIG35 shows the emission patterns of green quantum dot light-emitting layers with different concentrations according to an embodiment of the present disclosure;

[0066] FIG36 shows an electrospectral diagram of a green quantum dot light-emitting layer according to an embodiment of the present disclosure;

[0067] FIG37 shows the emission patterns of blue quantum dots under different development conditions according to an embodiment of the present disclosure;

[0068] FIG38 shows the light emission patterns of a red quantum dot light emitting layer and a red and green quantum dot light emitting layer according to an embodiment of the present disclosure;

[0069] FIG39 shows an electrospectral graph and a light-emitting pattern of a red quantum dot light-emitting layer according to an embodiment of the present disclosure;

[0070] FIG40 shows an electrospectral graph and a luminescent pattern of a green quantum dot light-emitting layer according to an embodiment of the present disclosure;

[0071] FIG41 shows a photograph of a patterned quantum dot light-emitting layer obtained by using a cross-linking agent including a diazide group in the related art;

[0072] FIG42 shows a schematic structural diagram of a light emitting device according to an embodiment of the present disclosure;

[0073] FIG43 shows a block diagram of a display device according to an embodiment of the present disclosure; and

[0074] FIG44 shows a schematic diagram of a process for preparing a patterned quantum dot light-emitting layer according to an embodiment of the present disclosure.

[0075] It should be understood that the accompanying drawings are merely schematic illustrations of exemplary embodiments of the present disclosure and are not intended to limit the present disclosure and are not necessarily drawn to scale. In addition, in the accompanying drawings, identical or similar components are indicated by identical or similar reference numerals. DETAILED DESCRIPTION

[0076] The following will clearly describe the technical solutions in the embodiments of the present disclosure in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of them. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0077] As used herein, unless a specific definition is otherwise provided, when a chemical bond is not drawn where it should be given, a hydrogen atom is bonded at that position.

[0078] Quantum dot light-emitting diode displays (LEDs) are a new display technology developed based on organic light-emitting diode (OLED) displays. They use quantum dots as their light-emitting layer. Their light-emitting principle is to inject holes and electrons into the quantum dot light-emitting layer through a hole transport layer and an electron transport layer, respectively. Holes and electrons recombine in the quantum dot light-emitting layer, thereby generating light. Compared to OLED displays, QD LEDs offer advantages such as higher color saturation, a wider color gamut, a narrower emission peak, and improved stability. With the advancement of quantum dot technology, research on quantum dot displays is becoming increasingly in-depth, and with the continuous improvement of quantum efficiency, industrialization is now practically possible. Therefore, developing new processes and technologies for the preparation of quantum dot light-emitting layers to further enhance the fabrication process of QD LED displays has become a future trend.

[0079] The traditional method for patterning a quantum dot light-emitting layer involves exposing and developing a photoresist layer to produce a patterned photoresist. The patterned photoresist is then used to block the quantum dot light-emitting layer and etch away unwanted portions, thereby forming a patterned quantum dot light-emitting layer. While traditional photoresist methods can achieve quantum dot patterning, their further application is limited by complex process flows and poor solvent compatibility. To address these limitations, the development of new quantum dot patterning methods is urgently needed.

[0080] Recently, the industry has proposed the possibility of directly exposing and developing quantum dot films to produce a patterned quantum dot light-emitting layer, eliminating the need for photoresist. This simple and cost-effective manufacturing method can produce high-quality patterned quantum dot light-emitting layers, thereby enabling higher-resolution quantum dot electroluminescent devices. When patterning the quantum dot light-emitting layer through direct photolithography, a crosslinker is added to the quantum dot solution to allow the crosslinker to react with the ligands on the quantum dot surface, thereby forming a patterned quantum dot light-emitting layer.

[0081] When a full-color device is prepared by directly patterning the quantum dot light-emitting layer, after exposure and development, ideally, only red quantum dots exist in the red sub-pixel area without green and blue quantum dots, only green quantum dots exist in the green sub-pixel area without red and blue quantum dots, and only blue quantum dots exist in the blue sub-pixel area without red and green quantum dots. However, the reality is that some quantum dots often remain in sub-pixel areas where they should not be. For example, red quantum dots remain in the green and blue sub-pixel areas in addition to the red sub-pixel area. As a result, when the green and blue quantum dot light-emitting layers are subsequently prepared, the green sub-pixel area includes not only green quantum dots but also residual red quantum dots, and the blue sub-pixel area includes not only blue quantum dots but also residual red quantum dots, resulting in color mixing problems and reducing the color gamut of the quantum dot electroluminescent device.

[0082] For example, FIG1 shows a schematic diagram of the patterning principle of the quantum dot light-emitting layer in the related art. As shown in FIG1 , an electron transport layer 12 is formed on the first electrode 11, and then a mixed solution (for example, the mixed solution includes red quantum dots, photosensitizer PAC, photoacid generator PAG, etc.) is spin-coated on the electron transport layer 12 and the mixed solution is cured to form a quantum dot film layer 13. Ultraviolet light is irradiated through the opening of the mask plate 14 to expose the quantum dot film layer 13, and then the quantum dot film layer 13 is developed using a developer. As a result, not only a patterned red quantum dot light-emitting layer 15 is formed in the exposed area (red sub-pixel area), but also red quantum dots 16 remain in the unexposed area (for example, the green and / or blue sub-pixel area). It was found that the reason for the residual red quantum dots 16 is that when the developer is used for development, the portion of the quantum dot film layer 13 located in the exposed area is insoluble in the developer, thereby forming a patterned red quantum dot light-emitting layer 15. However, since the electron transport layer 12 is formed by a sol-gel method, there is a certain van der Waals force between the electron transport layer 12 and the quantum dots. This van der Waals force causes the portion of the quantum dot film layer 13 in the unexposed area to remain slightly on the electron transport layer 12, resulting in red quantum dots 16 remaining in the green and / or blue sub-pixel areas.

[0083] In accordance with the above method, a patterned green quantum dot light-emitting layer and a blue quantum dot light-emitting layer are formed in the green sub-pixel area and the blue sub-pixel area respectively, and then a hole transport layer and a second electrode are formed in sequence on the side of the red, green and blue quantum dot light-emitting layer away from the electron transport layer 12 to form a quantum dot electroluminescent device.

[0084] As shown in Figure 2, for example, when the green sub-pixel of the aforementioned quantum dot electroluminescent device is subjected to electroluminescence testing, as the voltage gradually increases, it is found that the green sub-pixel not only has the electroluminescence spectrum peak of the green quantum dots, but also clearly has the electroluminescence spectrum peak of the red quantum dots, indicating that the red quantum dots remain in the green sub-pixel area. Therefore, when preparing a full-color device, red quantum dots will remain in the green and / or blue sub-pixel areas, resulting in color mixing. This greatly reduces the color gamut of the quantum dot electroluminescent device and weakens the advantages of quantum dots as electroluminescent materials.

[0085] In order to solve the problem of quantum dot residue, the industry has developed crosslinkers such as diazonaphthoquinone. As shown in Figure 3, under ultraviolet light, diazonaphthoquinone crosslinkers becomes Ligands on the quantum dot surface A cross-linking reaction occurs, forming a quantum dot light-emitting layer. However, when developing the quantum dot light-emitting layer with a developer, it was found that although the number of residual quantum dots in the unexposed areas was reduced, the quantum dot film layer in the exposed areas was more or less washed away by the developer, making it impossible to form the expected pattern shape. Moreover, the degree of washing away of the quantum dot film layer in the exposed areas fluctuated greatly with the experiment and was difficult to control.

[0086] Figure 4 shows the quantum dot film layer in the exposed area. As shown in Figure 4, the quantum dot pattern in the exposed area is damaged to varying degrees by the developer. In particular, the area outlined by the solid black circle has been largely washed away by the developer, severely damaging the pattern shape. This phenomenon may be due to insufficient crosslinking between the quantum dots and the crosslinker in the exposed area, coupled with low photoinitiation efficiency of the crosslinker.

[0087] To address the issues with existing technologies, there is an urgent need to develop new crosslinking agents to enhance the stability of the quantum dot light-emitting layer pattern. The quantum dot light-emitting layer formed by the crosslinking reaction between the new crosslinking agent and the quantum dots will not be damaged by the developer in the exposed areas of the quantum dot light-emitting layer, allowing the desired pattern shape to be formed intact. At the same time, the developer can rinse away the unexposed areas of the quantum dot light-emitting layer without any residue, thus avoiding color mixing caused by residual quantum dots.

[0088] The present disclosure provides a cross-linking agent having the general formula R-(R1): n , wherein R includes at least three reactive sites connected to R1.

[0089] FIG5 shows the chemical formula of the group R (or called the core R), which can be or or or or or or or or other appropriate groups. Represents a polymer chain, wherein the functional groups of the polymer chain include at least one of a carboxyl group, a hydroxyl group, and an aldehyde group. n In the embodiment, R1 includes an azide group N3, n is a positive integer greater than or equal to 3, and the value of n is equal to the number of reactive sites on R.

[0090] The azide group N3 has a relatively high photoinitiation efficiency, a relatively low exposure dose, and a good quantum dot patterning effect, making it a preferred material as a crosslinking agent. The crosslinking agent provided in the embodiments of the present disclosure has the general formula R-(R1): n, the group R has at least three reaction sites that can be connected to the group R1, therefore, each group R can be connected to at least three groups R1, and each R1 includes at least one azide group N3, therefore, each cross-linker molecule includes at least three azide groups N3, and has a high degree of cross-linking. The quantum dot light-emitting layer formed by the cross-linking reaction between the cross-linker and the quantum dots has high stability, thereby improving the stability of the quantum dot light-emitting layer in the exposed area. Under the action of the developer, the portion of the quantum dot light-emitting layer in the exposed area will not be destroyed by the developer, and the expected pattern shape can be formed intactly; at the same time, the portion of the quantum dot light-emitting layer in the unexposed area can be washed away by the developer, and no residue will remain, thereby avoiding the color mixing phenomenon caused by quantum dot residue. By using the cross-linking agent provided in the embodiment of the present disclosure, the problem of quantum dot residue can be solved, and a high-quality quantum dot pattern can be obtained.

[0091] Figure 6 shows the general formula R-(R1) n The chemical formula of the group R1 in is Wherein any one of R2 to R6 is a conjugated group or a non-conjugated group, and the conjugated group or the non-conjugated group is connected to the reactive site on R, and the remaining groups of R2 to R6 except the group connected to the reactive site on R can be the same or different from each other and can be selected from fluorine atoms or hydrogen atoms. Depending on the position of the absorption peak, the chemical bond connecting R and R1 is designed to be a conjugated group or a non-conjugated group. In some embodiments, the para-position group R4 of the azide group N3 is connected to the reactive site on R. In this case, the group R4 is a conjugated group or a non-conjugated group, and the remaining groups R2, R3, R5, and R6 are the same or different from each other and can be fluorine atoms or hydrogen atoms respectively. In some alternative embodiments, the ortho-position group R2 (or R6) of the azide group N3 is connected to the reactive site on R. In this case, the group R2 (or R6) is a conjugated group or a non-conjugated group, and the remaining groups R3, R4, R5, and R6 (or R2, R3, R4, and R5) are the same or different from each other and can be fluorine atoms or hydrogen atoms respectively. In some alternative embodiments, the meta group R3 (or R5) of the azide group N3 is connected to the reaction site on R, in which case the group R3 (or R5) is a conjugated group or a non-conjugated group, and the remaining groups R2, R4, R5, R6 (or R2, R3, R4, R6) are the same as or different from each other and can be fluorine atoms or hydrogen atoms, respectively.

[0092] The azide group N3 can generate nitrogen carbene radicals under light, which are highly active and can undergo insertion reaction with the carbon-hydrogen bond of the quantum dot ligand to form a cross-linked structure. When the para, or adjacent, or meta position of the azide group N3 is a fluorine atom, it is beneficial to better stabilize the nitrogen carbene radical and promote the insertion reaction between the crosslinker and the carbon-hydrogen bond of the quantum dot ligand.

[0093] When the crosslinking agent absorbs at 254 nm, the group on R1 connected to the reactive site on R needs to be a non-conjugated group. For example, the non-conjugated group may include at least one of an ester group, an amide group, an ether group, an imine group, and a carbon-nitrogen double bond.

[0094] When the crosslinker absorbs at 365 nm, the group on R1 that is connected to the reactive site on R needs to be a conjugated group. For example, the conjugated group can include a carbon-carbon double bond. 365 nm is a relatively ideal absorption peak position because it is less harmful to quantum dots.

[0095] The group on R1 connected to the reaction site on R also needs to consider the principle of like dissolves like between molecules to achieve compatibility between the crosslinker and the quantum dots. For example, if the quantum dots and the corresponding solvent have been determined, the compatibility between the crosslinker and the quantum dots can be achieved by designing the type of group on R1 connected to the reaction site on R. For example, quantum dots have good dispersibility in the solvent propylene glycol methyl ether acetate (PGMEA for short). When PGMEA is selected as the quantum dot solvent, since PGMEA contains an ester group, in order to improve the solvent compatibility between the crosslinker and the quantum dots, the group on R1 connected to the reaction site on R can also be selected as an ester group.

[0096] As shown in Figure 7, when R is When the group R4 of R1 is connected to the reactive site of R, the chemical formula of the crosslinker can be expressed as The cross-linker comprises three azide groups N3.

[0097] As shown in Figure 8, when R is When the group R4 of R1 is connected to the reactive site of R, the chemical formula of the crosslinker can be expressed as The cross-linker comprises three azide groups N3.

[0098] As shown in Figure 9, when R is When the group R4 of R1 is connected to the reactive site of R, the chemical formula of the crosslinker can be expressed as The cross-linker comprises four azide groups N3.

[0099] As shown in Figure 10, when R is When the group R4 of R1 is connected to the reactive site of R, the chemical formula of the crosslinker can be expressed as The cross-linker comprises four azide groups N3.

[0100] As shown in Figure 11, when R is When the group R4 of R1 is connected to the reactive site of R, the chemical formula of the crosslinker can be expressed as The cross-linker comprises four azide groups N3.

[0101] As shown in Figure 12, when R is When the group R4 of R1 is connected to the reactive site of R, the chemical formula of the crosslinker can be expressed as The cross-linker comprises five azide groups N3.

[0102] As shown in Figure 13, when R is When the group R4 of R1 is connected to the reactive site of R, the chemical formula of the crosslinker can be expressed as The cross-linker comprises six azide groups N3.

[0103] In the chemical formulas of Figures 7-13, as described above, the group R4 can be a conjugated group or a non-conjugated group, and the remaining groups R2, R3, R5, and R6 can be the same or different and can each be a fluorine atom or a hydrogen atom. The non-conjugated group can include at least one of an ester group, an amide group, an ether group, an imine group, and a carbon-nitrogen double bond, and the conjugated group can be, for example, a carbon-carbon double bond.

[0104] In some embodiments, when the group R is a polymer chain, the general formula R-(R1) n The molecular weight of the polymer can be 10,000 to 30,000, for example, 10,000, 20,000, 30,000, etc. For example, the value of n can be any integer between approximately 80 and 120, meaning that a single polymer molecule can include 80 to 120 azide groups N3, for example, 80 azide groups N3, 100 azide groups N3, 120 azide groups N3, etc. The functional groups of the polymer chain include at least one of a carboxyl group, a hydroxyl group, and an aldehyde group. In one example, the polymer chain can be polymethacrylic acid. In an alternative example, the polymer chain can be polyvinylphenol.

[0105] In some embodiments, the chemical formula of R1 is R4 is connected to the reactive site on R. That is, in this chemical formula, the para-position R4 of the azide group N3 is connected to the reactive site on R, the group R4 can be a conjugated group or a non-conjugated group, and the remaining groups R2, R3, R5, and R6 are all fluorine atoms. The hydrogen atoms at the para and meta positions of the azide group N3 are replaced by fluorine atoms, which helps to better stabilize the nitrogen carbene radical and promote the insertion reaction between the carbon-hydrogen bond of the crosslinker and the quantum dot ligand.

[0106] As shown in FIG14 , in some embodiments, when R is And R1 is When the general formula is R-(R1) n Where n is equal to 4, the chemical formula of the cross-linking agent is

[0107] In this chemical formula, the central parent nucleus R is tetraphenylethylene, which has four reactive sites and can therefore be linked to four groups R1. This means the crosslinker includes four azide groups N3. Because azide groups N3 have high photoinitiation efficiency, crosslinkers containing tetrasubstituted azide groups N3 exhibit a high degree of crosslinking. Using this crosslinker can improve the stability of the quantum dot light-emitting layer.

[0108] When the group R4 in the chemical formula of Figure 14 is selected to be different groups, the crosslinking agent can have different molecular structures. Below, several crosslinking agents with different molecular structures and their preparation methods are listed.

[0109] As shown in FIG15 , when R4 is a carbon-nitrogen double bond, the chemical formula of the cross-linking agent in FIG14 becomes The crosslinking agent may be referred to as TPE-4N3.

[0110] Figure 16 shows the synthesis route of TPE-4N3. The synthesis method is as follows: weigh a certain mass (e.g. 392 mg) of reactants and a certain mass (e.g. 860 mg) of reactants The two reactants were placed in a reaction vessel, methanol was added to the reaction vessel, and the mixture was refluxed at 60° C. to obtain a yellow solid powder. The yellow solid powder was rinsed with methanol and dried to obtain the product TPE-4N3.

[0111] FIG17 shows the H NMR spectrum of TPE-4N3, which indicates that the molecular structure of the synthesized TPE-4N3 is correct.

[0112] As shown in FIG18 , when R4 is an ester group, the chemical formula of the cross-linking agent in FIG14 becomes Although FIG. 18 shows the azide group N3 in a para position relative to the ester group, as previously described, the azide group N3 may also be in an ortho or meta position relative to the ester group.

[0113] Figure 19 shows the synthesis route of the cross-linking agent of Figure 18. The synthesis method is as follows: weigh a certain amount of reactants and a certain mass of reactants The two reactants are placed in a reaction vessel, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC), 4-dimethylaminopyridine (DMAP) and dichloromethane (DCM) are added to the reaction vessel. The reaction is carried out at room temperature for a period of time to finally obtain the product.

[0114] As shown in FIG20 , when R4 is an ester group, the chemical formula of the cross-linking agent in FIG14 can also be

[0115] Figure 21 shows the synthesis route of the cross-linking agent of Figure 20. The synthesis method is as follows: weigh a certain amount of reactants and a certain mass of reactants Place the two reactants in a reaction vessel, add EDC, DMAP and DCM to the reaction vessel, react at room temperature for a period of time, and finally obtain the product

[0116] As shown in FIG22, when R4 is an amide group, the chemical formula of the cross-linking agent in FIG14 becomes

[0117] Figure 23 shows the synthesis route of the cross-linking agent of Figure 22. The synthesis method is as follows: weigh a certain amount of reactants and a certain mass of reactants Place the two reactants in a reaction vessel, add EDC, DMAP and DCM to the reaction vessel, react at room temperature for a period of time, and finally obtain the product

[0118] As shown in FIG24 , when R4 is a carbon-carbon double bond, the chemical formula of the cross-linking agent in FIG14 becomes

[0119] Figure 25 shows the synthesis route of the cross-linking agent of Figure 24. The synthesis method is as follows: weigh a certain amount of reactants and a certain mass of reactants The two reactants were placed in a reaction vessel, sodium ethoxide and methanol were added to the reaction vessel, and refluxed at 60°C for a period of time to finally obtain the product.

[0120] The selection of the crosslinker group R4 mainly considers factors such as solubility, the source of raw materials, and the difficulty of post-processing. In terms of solubility, based on the principle of like dissolves like between molecules, the crosslinker and quantum dots are ensured to have good compatibility. For example, when the solvent of the quantum dots contains an ester group, the crosslinker group R4 can be selected as an ester group. When the solvent of the quantum dots contains an amide group, the crosslinker group R4 can be selected as an amide group. When the solvent of the quantum dots contains a carbon-nitrogen double bond, the crosslinker group R4 can be selected as a carbon-nitrogen double bond. When the solvent of the quantum dots contains a carbon-carbon double bond, the crosslinker group R4 can be selected as a carbon-carbon double bond. When the solvent of the quantum dots contains an ether group, the crosslinker group R4 can be selected as an ether group.

[0121] In addition, it should be noted that the molecular structure of the cross-linking agent can be a symmetrical structure or an asymmetrical structure, and the embodiments of the present disclosure do not limit this.

[0122] In the cross-linking agent provided by each embodiment of the present disclosure, the group R has at least three reaction sites that can be connected to the group R1, so each group R can be connected to at least three groups R1, and each R1 includes at least one azide group N3, so the cross-linking agent includes at least three azide groups N3. Since the photoinitiation efficiency of the azide group N3 is relatively high, the cross-linking agent with a multi-substituted azide group N3 provided by each embodiment of the present disclosure has a high degree of cross-linking. When the cross-linking agent reacts with the quantum dots, the quantum dot light-emitting layer formed has a high stability, which helps to enhance the stability of the quantum dot light-emitting layer in the exposed area. Under the action of the developer, the part of the quantum dot light-emitting layer in the exposed area will not be destroyed by the developer, and the expected pattern shape can be formed intact; at the same time, the part of the quantum dot light-emitting layer in the unexposed area can be washed away by the developer without residue, thereby avoiding the color mixing phenomenon caused by quantum dot residue. By using the cross-linking agent provided by the embodiment of the present disclosure, the problem of quantum dot residue can be solved and high-quality quantum dot patterns can be obtained.

[0123] Figure 26 shows a schematic diagram of the structure of a quantum dot according to an embodiment of the present disclosure. As shown in Figure 26, the quantum dot includes a quantum dot body and a ligand modified on the quantum dot body by coordination, wherein the ligand includes a carbon-hydrogen bond and can undergo a cross-linking reaction with the cross-linking agent described in any of the previous embodiments under light radiation. Specifically, because the cross-linking agent includes an azide group N3, and the azide group N3 can generate a nitrogen carbene free radical under light radiation, which is relatively active, the cross-linking agent can undergo a nitrogen-hydrogen insertion reaction with the carbon-hydrogen bond of the ligand on the surface of the quantum dot under light radiation to form a cross-linked structure.

[0124] The ligand on the surface of the quantum dot can be any suitable ligand. In some embodiments, the ligand can be selected from any one of oleylamine, isooctyl mercaptan, thioglycolic acid, mercaptopropionic acid, oleic acid, and 2-mercaptoethyl Boc amine. The ligand on the surface of the quantum dot can fill defects on the surface of the quantum dot, thereby improving the stability and quantum yield of the quantum dot.

[0125] In some embodiments, the quantum dots are configured to emit red light or blue light (or referred to as red quantum dots or blue quantum dots), and the ligand on the surface of the quantum dots is oleic acid, and the molecular structure of oleic acid is After the red quantum dots or blue quantum dots with oleic acid ligands undergo a cross-linking reaction with the aforementioned cross-linking agent, a high-quality quantum dot patterned layer can be obtained.

[0126] In some alternative embodiments, the quantum dots are configured to emit green light (or referred to as green quantum dots), and the ligand on the surface of the quantum dots is 2-mercaptoethyl Boc amine, the chemical formula of which is After the green quantum dots having 2-mercaptoethyl Boc amine ligands undergo a cross-linking reaction with the aforementioned cross-linking agent, a high-quality quantum dot patterned layer can be obtained.

[0127] The quantum dots provided in the embodiments of the present disclosure may be any appropriate quantum dots, including but not limited to: any of group IIB-VIA quantum dots, group IIIA-VA quantum dots, group IVA-VIA quantum dots, core-shell quantum dots, and ABX3 type perovskite quantum dots. In the ABX3 type perovskite quantum dots, A is CH3NH3 + (methylamine), NH2CH=NH2(formamidine) and Cs + One or more of, B is Pb 2+ and Sn 2+ One or two of the following, X is Cl - Br - and I - One or more of the ABX3 type perovskite quantum dots include CH3NH3PbBr3, CH3NH3PbCl3, CH3NH3PbI3, CsPbBr3, CsPbCl3 and CsPbI3.

[0128] Exemplarily, the IIB-VIA group quantum dots are selected from: binary compounds such as one or more of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, and MgS; ternary compounds such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZn Te, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or mixtures thereof; and quaternary compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or mixtures thereof, but are not limited thereto.

[0129] The IIIA-VA group quantum dots are selected from: binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or mixtures thereof; ternary compounds such as GaNPs, GaNAs, GaNSb, GaPAs, GaPSb, AlNPs, AlNAs, AlNSb, AlPAs, AlPSb, InNPs, InNAs, InNSb, InPAs, InPSb, or mixtures thereof; and quaternary compounds such as GaAlNPs, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNPs, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNPs, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or mixtures thereof, but are not limited thereto.

[0130] Group IVA-VIA quantum dots are selected from, but are not limited to, binary compounds such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or mixtures thereof; ternary compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or mixtures thereof; and quaternary compounds such as SnPbSSe, SnPbSeTe, SnPbSTe, or mixtures thereof. Group IVA-VIA quantum dots are selected, for example, from elemental (mono) semiconductors such as Si, Ge, or mixtures thereof; and binary semiconductor compounds such as SiC, SiGe, and mixtures thereof.

[0131] Core-shell quantum dots are structures where one material is the core and the other is the shell. For example, a CdS / ZnS quantum dot is a quantum dot where the core is CdS and the shell is ZnS.

[0132] In some other embodiments, the quantum dots may be other nanoscale materials, such as nanorods, nanosheets, etc. The components of other nanoscale materials may include at least one of CdS, CdSe, CdTe, ZnSe, InP, PbS, CuInS2, ZnO, CsPbCl3, CsPbBr3, CsPhI3, CdS / ZnS, CdSe / ZnS, ZnSe, InP / ZnS, PbS / ZnS, InAs, InGaAs, InGaN, GaNk, ZnTe, Si, Ge, and C.

[0133] For example, quantum dots can include cadmium-free (Cd) quantum dots. Cadmium-free quantum dots are quantum dots that do not include cadmium (Cd). Cadmium (Cd) can cause serious environmental / health problems, so non-cadmium-based quantum dots can be effectively used.

[0134] According to another aspect of the present disclosure, a quantum dot composition is provided, comprising a mixed solution comprising the aforementioned quantum dots with ligands, a crosslinker as described in any of the preceding embodiments, and a solvent. The concentration of the quantum dots in the mixed solution may be approximately 20 to 35 mg / mL, e.g., 20 mg / mL, 30 mg / mL, 35 mg / mL, etc.; the concentration of the crosslinker in the mixed solution may be approximately 0.1 to 2.0 mg / mL, e.g., 0.1 mg / mL, 0.5 mg / mL, 1.0 mg / mL, 1.5 mg / mL, 2.0 mg / mL, etc.

[0135] As previously described, the quantum dot composition comprises a quantum dot body and a ligand modified onto the quantum dot body through coordination, wherein the ligand comprises a carbon-hydrogen bond. For example, the ligand can be selected from oleylamine, isooctylmercaptan, thioglycolic acid, mercaptopropionic acid, oleic acid, and 2-mercaptoethyl Boc-amine. After the mixed solution is cured, under light irradiation, the azide group N3 of the crosslinker can undergo a nitrogen-hydrogen insertion reaction with the carbon-hydrogen bonds of the ligands on the quantum dot surface, forming a crosslinked structure.

[0136] The solvent in the quantum dot composition can be any suitable type of solvent. In some embodiments, the solvent can be, for example, propylene glycol monomethyl ether acetate (PGMEA), toluene, chlorobenzene, octane, water, or an alcohol. Both the quantum dots and the crosslinker have good solubility in PGMEA, and the solvent is environmentally friendly.

[0137] According to another aspect of the present disclosure, a quantum dot light-emitting layer is provided, which includes a plurality of quantum dots, at least some of which include a quantum dot body and a ligand modified on the quantum dot body through coordination, and the quantum dot light-emitting layer is generated by cross-linking quantum dots with ligands and the cross-linking agent described in any of the previous embodiments.

[0138] In some embodiments, when each quantum dot has a ligand on its surface, the general formula of the quantum dot light-emitting layer can be expressed as R-(R1'-R7-QD) n , wherein QD represents a quantum dot, R7 represents a ligand on the surface of the quantum dot and includes a carbon-hydrogen bond, R is a parent core structure of a cross-linking agent, R includes at least three reaction sites capable of connecting with R1, and R can be or or or or or or or or other appropriate groups. represents a polymer chain, wherein the functional groups of the polymer chain include at least one of a carboxyl group, a hydroxyl group, and an aldehyde group. n is a positive integer greater than or equal to 3, and the value of n is equal to the number of reactive sites on R. R1' represents a group after the azide group N3 on R1 is converted to NH by a nitrogen-hydrogen insertion reaction. In some embodiments, the chemical formula of R1' can be represented as Wherein any one of R2 to R6 is a conjugated group or a non-conjugated group, the conjugated group or non-conjugated group is connected to the reactive site on R, and the remaining groups of R2 to R6, excluding the group connected to the reactive site on R, may be the same or different and may be selected from fluorine atoms or hydrogen atoms. The non-conjugated group may include at least one of an ester group, an amide group, an ether group, an imine group, and a carbon-nitrogen double bond. The conjugated group may include a carbon-carbon double bond.

[0139] The quantum dot light-emitting layer can be applied to the field of electroluminescence, and can also be applied to the field of photoluminescence.

[0140] In the field of electroluminescence, for example, a quantum dot light-emitting layer can be used as a light-emitting layer in a quantum dot light-emitting diode device. Under the action of an electric field, electrons and holes generated in the device are transferred to the quantum dot light-emitting layer, and recombine into excitons in the quantum dot light-emitting layer, generating energy level transitions and thus emitting light.

[0141] In the field of photoluminescence, the quantum dot light-emitting layer can be integrated into the backlight; or, the quantum dot light-emitting layer can be used as a color film and integrated inside the panel, and can be applied to liquid crystal display panels, organic light-emitting diode display panels, or sub-millimeter organic light-emitting diode display panels; or, the quantum dot light-emitting layer can be set on the light-emitting side of an organic light-emitting diode display panel that emits blue light, and emit red, green and blue light under the excitation of blue light, thereby achieving full-color display.

[0142] Figure 27 shows a chemical formula of a quantum dot light-emitting layer. And R1' is When R4 is connected to the reactive site on R, the general formula is R-(R1'-R7-QD) n It can be expressed as Wherein, QD represents a quantum dot, R7 is a ligand on the surface of the quantum dot and includes a carbon-hydrogen bond, R4 is a conjugated group or a non-conjugated group, and R2, R3, R5, and R6 can be the same or different and can be selected from fluorine atoms or hydrogen atoms. The conjugated group can include, for example, a carbon-carbon double bond, and the non-conjugated group can include, for example, at least one of an ester group, an amide group, an ether group, an imine group, and a carbon-nitrogen double bond.

[0143] The chemical formula of the quantum dot light-emitting layer shows that the parent nucleus R of the crosslinker used for crosslinking with the quantum dots is tetraphenylethylene. Since tetraphenylethylene has four reactive sites, it can be linked to four groups R1, meaning the crosslinker includes four azide groups N3. When the crosslinker reacts with the quantum dots under light irradiation, the azide groups N3 of the crosslinker undergo nitrogen-hydrogen insertion reactions with the carbon-hydrogen bonds of the quantum dot surface ligands R7. The azide groups N3 on the R1 groups are converted to NH groups, which then link to the ligands R7, thereby forming a crosslinked quantum dot light-emitting layer. The presence of four substituted azide groups N3 in the crosslinker can increase the degree of crosslinking between the crosslinker and the quantum dots, resulting in a highly stable quantum dot light-emitting layer. When developing such a quantum dot light-emitting layer with a developer, the exposed portions of the quantum dot light-emitting layer are not damaged by the developer, allowing the desired pattern to be formed intact. Simultaneously, the unexposed portions of the quantum dot light-emitting layer can be rinsed away by the developer, leaving no residue, thus avoiding color mixing caused by residual quantum dots. In this way, the problem of quantum dot residue can be solved and high-quality quantum dot patterns can be obtained.

[0144] FIG28 shows a chemical formula of a quantum dot light-emitting layer, which is Where QD represents quantum dots, and R7 represents the ligand on the surface of quantum dots. R7 is oleic acid, and its chemical formula is The quantum dot light-emitting layer can be a red quantum dot light-emitting layer or a blue quantum dot light-emitting layer.

[0145] FIG29 shows a synthesis route of the quantum dot light-emitting layer of FIG28 . The preparation process of the quantum dot light-emitting layer of FIG28 will be described below in conjunction with FIG29 .

[0146] First, a solution of an electron transport layer is spin-coated on a substrate to form an electron transport layer. The electron transport layer can be formed of any suitable material. For example, the material of the electron transport layer can be nanoparticle zinc oxide (ZnO), or metal-doped nano zinc oxide, or sol-gel (Sol-Gel) type zinc oxide (ZnO). For example, metal-doped nano zinc oxide can include zinc oxide (ZnO) doped with magnesium (Mg), aluminum (Al), zirconium (Zr) or yttrium (Y). In some embodiments, the material of the electron transport layer is nanoparticle structured ZnO. For example, nanoparticle structured ZnO can be formed by a sol-gel method. In some embodiments, the concentration of ZnO in the solution can be 75 mg / mL, the speed of spinning the solution on the substrate can be 3000 rpm, and the heating temperature required in the sol-gel process can be about 300°C.

[0147] Then, a mixed solution including a cross-linking agent, quantum dots with ligands, and a solvent is prepared. The cross-linking agent is the aforementioned cross-linking agent It is abbreviated as TPE-4N3, and the ligand R7 on the surface of the quantum dot QD is oleic acid. The quantum dot with the ligand can be abbreviated as QD-R7. Since the quantum dot QD-R7 with oleic acid ligand has good solubility in chlorobenzene (for example, solubility>30mg / mL), the crosslinker TPE-4N3 also has good solubility in chlorobenzene (for example, solubility>5mg / mL), the solvent can be selected as chlorobenzene to make the crosslinker TPE-4N3 and the quantum dot QD-R7 better compatible. In some embodiments, the concentration of the quantum dot QD-R7 in the mixed solution can be designed to be 30mg / mL, and the concentration of the crosslinker TPE-4N3 in the mixed solution can be designed to be 1mg / mL. The mixed solution is spin-coated on the electron transport layer and cured to form a solidified layer. It is then exposed to ultraviolet light, and the exposure time can be, for example, about 60s. The four azide groups N3 in the crosslinker TPE-4N3 generate highly reactive nitrogen carbene radicals under UV light, which undergo a nitrogen-hydrogen insertion reaction with the carbon-hydrogen bonds of the oleic acid ligand R7 on the quantum dot surface. After this reaction, the azide groups N3 become NH, which then connects to the ligand R7, forming a cross-linked quantum dot light-emitting layer.

[0148] It should be noted that oleic acid Including multiple carbon-hydrogen bonds, the azide group N3 of the crosslinker TPE-4N3 can undergo nitrogen-hydrogen insertion reaction at any carbon-hydrogen bond position of oleic acid, without limiting the insertion reaction position. In the embodiment, NH can be connected to any carbon atom of the oleic acid ligand R7.

[0149] In one example, the quantum dot light-emitting layer is a red quantum dot light-emitting layer, which is used to emit red light.

[0150] Then, the exposed red quantum dot light-emitting layer is developed using a developer to obtain a patterned red quantum dot light-emitting layer.

[0151] Figure 30 explores the effects of different developer concentrations and different development times on the quantum dot pattern. Figure 30(a) shows a photopatterned photograph of the red quantum dot light-emitting layer, where the oblique straight line represents the shape of the patterned red quantum dot light-emitting layer in the exposed area when it is illuminated, and the black area represents the unexposed area. In Figure 30(a), the thickness of the red quantum dot light-emitting layer is 24nm, the corresponding developer concentration is 1%, and the development time is 30s. Figure 30(b) shows a photopatterned photograph of the red quantum dot light-emitting layer, where the oblique straight line represents the shape of the patterned red quantum dot light-emitting layer in the exposed area when it is illuminated, and the black area represents the unexposed area. In Figure 30(b), the thickness of the red quantum dot light-emitting layer is 14nm, the corresponding developer concentration is 1%, and the development time is 60s. Figure 30(c) shows a photopatterned photograph of the red quantum dot light-emitting layer, where the oblique straight line represents the shape of the patterned red quantum dot light-emitting layer in the exposed area when it is illuminated, and the black area represents the unexposed area. In FIG30( c ), the thickness of the red quantum dot light-emitting layer is 18 nm, the corresponding developer concentration is 1.25%, and the development time is 30 s.

[0152] As can be seen from Figures 30(a), 30(b), and 30(c), under the three different development conditions, the red quantum dot light-emitting layer in the exposed areas maintains a well-defined pattern shape, undamaged by the developer. Simultaneously, the red quantum dot light-emitting layer in the unexposed areas (e.g., the green and blue sub-pixels) is completely washed away by the developer, leaving no red quantum dots. This demonstrates the high stability of the red quantum dot light-emitting layer. Under the action of the developer, a high-quality quantum dot pattern can be formed in the exposed areas while avoiding any quantum dot residue in the unexposed areas, thus preventing color mixing.

[0153] The reason for the high stability of the red quantum dot light-emitting layer is that it is generated by cross-linking the crosslinker TPE-4N3 with red quantum dots containing oleic acid ligands. Each crosslinker molecule TPE-4N3 has four azide groups N3. Because the azide group N3 has a high photoinitiation efficiency and a low exposure dose, and can generate nitrogen carbene radicals under light radiation, the crosslinker TPE-4N3 has high activity. When the crosslinker TPE-4N3 and the red quantum dots containing oleic acid ligands undergo a cross-linking reaction under light radiation, the crosslinker TPE-4N3 can undergo a nitrogen-hydrogen insertion reaction with the carbon-hydrogen bonds of the oleic acid ligands on the surface of the quantum dots, forming a stable cross-linked structure. As a result, the formed red quantum dot light-emitting layer has high stability and will not be destroyed by the developer. Therefore, a high-quality red quantum dot pattern can be formed in the exposed area. Moreover, this further shows that the crosslinker TPE-4N3 is an ideal crosslinker.

[0154] In order to further verify that there are no red quantum dots remaining in the unexposed areas, green quantum dot patterns and blue quantum dot patterns were further prepared based on the above three red quantum dot patterns, and then the hole transport layer material and electrode material were evaporated, and the device packaging was completed to form three quantum dot light-emitting devices.

[0155] Figure 31 shows the electrospectral graphs of the green sub-pixels of three quantum dot light-emitting devices, where Figure 31(a) corresponds to the experimental conditions of Figure 30(a), i.e., UV exposure for 60s, a developer concentration of 1%, and a development time of 30s; Figure 31(b) corresponds to the experimental conditions of Figure 30(b), i.e., UV exposure for 60s, a developer concentration of 1%, and a development time of 60s; Figure 31(c) corresponds to the experimental conditions of Figure 30(c), i.e., UV exposure for 60s, a developer concentration of 1.25%, and a development time of 30s. Electrospectral testing of the green sub-pixels of the quantum dot light-emitting devices revealed that as the voltage gradually increased (for example, from 4V to 8V), the three electrospectral graphs showed peaks only at positions corresponding to the green wavelength, but no peaks at positions corresponding to the red wavelength. This indicates that there are only green quantum dots in the green sub-pixels, but no red quantum dots. Similarly, electrochemical testing of the blue sub-pixel yielded similar results: a peak appeared only at the wavelength corresponding to blue light, while no peak was observed at the wavelength corresponding to red light, indicating that the blue sub-pixel contained only blue quantum dots, not red quantum dots. Therefore, it was confirmed that when the red quantum dot light-emitting layer formed using the crosslinker TPE-4N3 is developed with a developer, the unexposed areas of the red quantum dot light-emitting layer can be washed away by the developer, leaving no residue.

[0156] Next, the inventors further explored the patterning of green quantum dots. The inventors prepared a green quantum dot light-emitting layer with reference to the preparation method of the red quantum dot light-emitting layer. Specifically, first, an electron transport layer solution is spin-coated on the substrate. The material of the electron transport layer can be, for example, ZnO, which has a nanoparticle structure. For example, the electron transport layer can be formed by a sol-gel method. For example, the concentration of ZnO in the solution can be 75 mg / mL, the spin-coating speed can be 3000 rpm, and the heating temperature required in the sol-gel process can be approximately 300°C. Then, a mixed solution is prepared including a crosslinker TPE-4N3, green quantum dots with ligands on the surface, and a chlorobenzene solvent. The ligands on the surface of the green quantum dots are oleic acid. The concentration of the green quantum dots in the mixed solution is 30 mg / mL, and the concentration of the crosslinker in the mixed solution is 1 mg / mL. The mixed solution is spin-coated on the electron transport layer and cured to form a cured layer. Then, ultraviolet light is used for exposure, and the exposure time can be, for example, approximately 60 seconds. Then, the exposed green quantum dot light-emitting layer was developed under three different development conditions: (1) a developer with a concentration of 1% and a development time of 30 s, (2) a developer with a concentration of 1% and a development time of 60 s, and (3) a developer with a concentration of 1.25% and a development time of 30 s.

[0157] Figure 32 shows the green quantum dot patterns obtained under three different development conditions, where Figure 32(a) corresponds to development condition (1), Figure 32(b) corresponds to development condition (2), and Figure 32(c) corresponds to development condition (3). As can be seen from Figure 32, the three green quantum dot light-emitting layers did not form the expected regular pattern shape in the exposed area. On the contrary, they all had disordered patterns, and the three green quantum dot light-emitting layers in the unexposed area were basically not washed away by the developer.

[0158] The green quantum dot light-emitting layer has the same ligands as the red quantum dot light-emitting layer, and uses the same crosslinker, solvent, and developer. The only difference is the color of the quantum dots' emission. However, as shown in the figure, the patterning results of the two are very different. The inventors believe that this may be due to the relatively poor colloidal stability of the green quantum dots and the possible defects on the surface of the electron transport layer ZnO. Since the volume of green quantum dots is generally smaller than that of red quantum dots, green quantum dots are more likely to bind to defects on the ZnO surface than red quantum dots, making them more difficult to be washed away by the developer, resulting in a more obvious residue phenomenon.

[0159] In order to solve the patterning problem of green quantum dots, the inventors proposed that it is necessary to explore new ligand materials and change the polarity of the ligands on the surface of green quantum dots, thereby adjusting the interaction between the green quantum dot ligands and ZnO.

[0160] FIG33 shows a chemical formula of a quantum dot light-emitting layer, which is Where QD represents quantum dots, and R7 represents a ligand on the surface of the quantum dots. R7 is 2-mercaptoethyl Boc amine, and the chemical formula of 2-mercaptoethyl Boc amine is The quantum dot light-emitting layer is a green quantum dot light-emitting layer configured to emit green light.

[0161] FIG34 shows a synthesis route of the green quantum dot light-emitting layer of FIG33 . The preparation process of the green quantum dot light-emitting layer of FIG33 will be roughly described below in conjunction with FIG34 .

[0162] First, a solution of an electron transport layer is spin-coated on a substrate to form an electron transport layer. The electron transport layer can be formed of any suitable material. For example, the material of the electron transport layer can be nanoparticle zinc oxide (ZnO), or metal-doped nano zinc oxide, or sol-gel (Sol-Gel) type zinc oxide (ZnO). For example, metal-doped nano zinc oxide can include zinc oxide (ZnO) doped with magnesium (Mg), aluminum (Al), zirconium (Zr) or yttrium (Y). In some embodiments, the material of the electron transport layer is nanoparticle structured ZnO. For example, nanoparticle structured ZnO can be formed by a sol-gel method. In some embodiments, the concentration of ZnO in the solution can be 75 mg / mL, the speed of spinning the solution on the substrate can be 3000 rpm, and the heating temperature required in the sol-gel process can be about 300°C.

[0163] Then, a mixed solution including a crosslinker TPE-4N3, green quantum dots with ligands, and a chlorobenzene solvent was prepared. The ligand R7 on the surface of the green quantum dot QD is 2-mercaptoethyl Boc amine. In order to make the experimental results more universal, three mixed solutions with different concentrations were prepared. In one mixed solution, the concentration of green quantum dots QD-R7 is 30 mg / mL, and the concentration of the crosslinker TPE-4N3 is 1 mg / mL; in another mixed solution, the concentration of green quantum dots QD-R7 is 25 mg / mL, and the concentration of the crosslinker TPE-4N3 is 1 mg / mL; in another mixed solution, the concentration of green quantum dots QD-R7 is 20 mg / mL, and the concentration of the crosslinker TPE-4N3 is 1 mg / mL. The three mixed solutions are spin-coated on the electron transport layer respectively, and after curing, three cured layers are formed. The cured layer is then exposed to ultraviolet light, and the exposure time can be about 60s, for example, to form a cross-linked structure. Then, the three exposed cross-linked structures are developed separately using a developer, and the development time may be, for example, about 30 seconds.

[0164] It should be noted that the ligand 2-mercaptoethyl Boc amine Including multiple carbon-hydrogen bonds, the azide group N3 of the crosslinker TPE-4N3 can undergo nitrogen-hydrogen insertion reaction at any carbon-hydrogen bond position of 2-mercaptoethyl Boc amine, without limiting the insertion reaction position. In the embodiment, NH can be connected to any carbon atom of R7 (i.e., 2-mercaptoethyl Boc amine).

[0165] Figure 35 shows three types of photopatterned green quantum dot light-emitting layers obtained using mixed solutions of three different concentrations, wherein Figure 35(a) corresponds to a green quantum dot QD-R7 concentration of 30 mg / mL and a crosslinker TPE-4N3 concentration of 1 mg / mL; Figure 35(b) corresponds to a green quantum dot QD-R7 concentration of 25 mg / mL and a crosslinker TPE-4N3 concentration of 1 mg / mL; and Figure 35(c) corresponds to a green quantum dot QD-R7 concentration of 20 mg / mL and a crosslinker TPE-4N3 concentration of 1 mg / mL. In Figures 35(a), 35(b), and 35(c), the oblique or horizontal straight lines represent the shape of the patterned green quantum dot light-emitting layer in the exposed area when it is lit, and the black area represents the unexposed area.

[0166] As can be seen from Figure 35, the three green quantum dot light-emitting layers all have a good pattern shape in the exposed area and are not damaged by the developer. Moreover, under a microscope, the three green quantum dot light-emitting layers in the unexposed area (such as the adjacent red and blue sub-pixel areas) are all washed away by the developer, leaving no residue. This indicates that replacing the ligand oleic acid with the ligand 2-mercaptoethyl Boc amine changes the polarity of the ligand on the surface of the green quantum dots, thereby weakening the interaction between the green quantum dot ligand and the electron transport layer ZnO. This makes the portion of the green quantum dot light-emitting layer in the unexposed area more easily washed away by the developer, thus solving the residue problem and avoiding color mixing.

[0167] The green quantum dot light-emitting layer has high stability. Under the action of the developer, it can form a high-quality quantum dot pattern in the exposed area, while avoiding the occurrence of quantum dot residues in the unexposed area and avoiding color mixing. The green quantum dot light-emitting layer has high stability because it is generated by crosslinking the green quantum dot with a 2-mercaptoethyl Bocamine ligand and the crosslinker TPE-4N3. Each crosslinker molecule TPE-4N3 has four azide groups N3. Because the azide groups N3 have high photoinitiation efficiency and low exposure dose, and can generate nitrogen carbene radicals under light radiation, the crosslinker TPE-4N3 has high activity. When the crosslinker TPE-4N3 and the green quantum dots containing the 2-mercaptoethyl Bocamine ligand undergo crosslinking under light radiation, the crosslinker TPE-4N3 can undergo a nitrogen-hydrogen insertion reaction with the carbon-hydrogen bonds of the 2-mercaptoethyl Bocamine ligand on the surface of the quantum dots, forming a stable crosslinked structure. This makes the green quantum dot light-emitting layer highly stable and will not be destroyed by the developer, so a high-quality green quantum dot pattern can be formed in the exposed area. Moreover, this further demonstrates that the crosslinker TPE-4N3 is an ideal crosslinker.

[0168] In order to further verify that there is no green quantum dot residue in the unexposed area, red quantum dot patterns and blue quantum dot patterns are further prepared based on any one of the three green quantum dot patterns mentioned above, and then the hole transport layer material and electrode material are evaporated, and the device is packaged to form a quantum dot light-emitting device.

[0169] Figure 36 shows the electrospectral graph of the red sub-pixel of the quantum dot light-emitting device. When the red sub-pixel is electro-tested, as the voltage gradually increases (for example, from 4V to 8V), it is found that the electrospectral graph only has a peak at the position corresponding to the red light wavelength, and no peak at the position corresponding to the green light wavelength. This shows that there are only red quantum dots in the red sub-pixel, and no green quantum dots. Similarly, if the blue sub-pixel is electro-tested, a similar result can be obtained, that is, a peak only appears at the position corresponding to the blue light wavelength, and no peak at the position corresponding to the green light wavelength, indicating that there are only blue quantum dots in the blue sub-pixel, and no green quantum dots. Therefore, it can be determined that the green quantum dot light-emitting layer formed by the cross-linking agent TPE-4N3 and the quantum dots containing 2-mercaptoethyl Bocamine ligands, when the green quantum dot light-emitting layer is developed with a developer, the portion of the green quantum dot light-emitting layer in the unexposed area can be washed away by the developer and will not remain. This shows that the residual problem of green quantum dots has been solved.

[0170] Next, the inventors further explored the patterning of blue quantum dots. The inventors prepared a blue quantum dot light-emitting layer by referring to the preparation method of the red quantum dot light-emitting layer. The chemical formula of the blue quantum dot light-emitting layer is Where QD represents quantum dots, and R7 represents the ligand on the surface of quantum dots. R7 is oleic acid, and its chemical formula is

[0171] Specifically, a solution of an electron transport layer is first spin-coated on a substrate to form an electron transport layer. The electron transport layer can be formed of any suitable material. For example, the material of the electron transport layer can be nanoparticle zinc oxide (ZnO), or metal-doped nano zinc oxide, or sol-gel (Sol-Gel) type zinc oxide (ZnO). For example, metal-doped nano zinc oxide can include zinc oxide (ZnO) doped with magnesium (Mg), aluminum (Al), zirconium (Zr) or yttrium (Y). In some embodiments, the material of the electron transport layer is nanoparticle structured ZnO. For example, nanoparticle structured ZnO can be formed by a sol-gel method. In some embodiments, the concentration of ZnO in the solution can be 75 mg / mL, the speed of spinning the solution on the substrate can be 3000 rpm, and the heating temperature required in the sol-gel process can be about 300°C.

[0172] Next, a mixed solution is prepared, comprising the crosslinker TPE-4N3, blue quantum dots with ligands, and a chlorobenzene solvent. The surface ligand of the blue quantum dots is oleic acid. The concentration of the blue quantum dots in the mixed solution is 30 mg / mL, and the concentration of the crosslinker TPE-4N3 in the mixed solution is 1 mg / mL. The mixed solution is spin-coated on the electron transport layer and cured to form a solidified layer. The layer is then exposed to ultraviolet light, for example, for approximately 30 seconds. The exposed blue quantum dot light-emitting layer is then developed under two different development conditions: (a) a 1% developer solution with a development time of 30 seconds, and (b) a 0.75% developer solution with a development time of 30 seconds. The four azide groups N3 of the crosslinker TPE-4N3 generate highly active nitrogen carbene radicals under ultraviolet light, which can undergo nitrogen-hydrogen insertion reactions with the carbon-hydrogen bonds of the oleic acid ligands R7 on the surface of the quantum dots. After the nitrogen-hydrogen insertion reaction, the azide group N3 becomes NH, which is connected to the ligand R7, thereby forming a cross-linked blue quantum dot light-emitting layer. As mentioned above, NH can be connected to any carbon atom of the oleic acid ligand R7.

[0173] Figure 37 shows photographs of the photopatterned blue quantum dot light-emitting layer obtained under two different development conditions, where Figure 37(a) corresponds to the above-mentioned development condition (a), and Figure 37(b) corresponds to the above-mentioned development condition (b). The straight lines in the figure represent the shape of the patterned blue quantum dot light-emitting layer in the exposed area when it is illuminated, and the black area represents the unexposed area. As can be seen from Figure 37, both blue quantum dot light-emitting layers have good pattern shapes in the exposed area and are not damaged by the developer. In addition, the portions of both blue quantum dot light-emitting layers in the unexposed area are washed away by the developer, and no blue quantum dots remain. This shows that the blue quantum dot light-emitting layer has high stability. Under the action of the developer, it can form a high-quality blue quantum dot pattern in the exposed area while avoiding the appearance of blue quantum dot residue in the unexposed area, thus avoiding color mixing.

[0174] The reason for the high stability of the blue quantum dot light-emitting layer is that it is generated by cross-linking the blue quantum dots containing oleic acid ligands with the cross-linker TPE-4N3. Each cross-linker molecule TPE-4N3 has four azide groups N3. Because the azide groups N3 have high photoinitiation efficiency and low exposure dose, and can generate nitrogen carbene radicals under light radiation, the cross-linker TPE-4N3 has high activity. When the cross-linker TPE-4N3 and the blue quantum dots containing oleic acid ligands undergo a cross-linking reaction under light radiation, the cross-linker TPE-4N3 can undergo a nitrogen-hydrogen insertion reaction with the carbon-hydrogen bonds of the oleic acid ligands on the surface of the quantum dots, forming a stable cross-linked structure. As a result, the formed blue quantum dot light-emitting layer has high stability and will not be destroyed by the developer. Therefore, a high-quality blue quantum dot pattern can be formed in the exposed area. Moreover, this further shows that the cross-linker TPE-4N3 is an ideal cross-linker.

[0175] The inventors further conducted an overlay experiment on red and green quantum dots to explore the residual situation of green quantum dots on the patterned red quantum dot light-emitting layer, as well as the performance of red quantum dot light-emitting devices and green quantum dot light-emitting devices after the photolithography process.

[0176] First, a solution of an electron transport layer is spin-coated on a substrate to form an electron transport layer. The electron transport layer can be formed of any suitable material. For example, the material of the electron transport layer can be nanoparticle zinc oxide (ZnO), or metal-doped nano zinc oxide, or sol-gel (Sol-Gel) type zinc oxide (ZnO). For example, metal-doped nano zinc oxide can include zinc oxide (ZnO) doped with magnesium (Mg), aluminum (Al), zirconium (Zr) or yttrium (Y). In some embodiments, the material of the electron transport layer is nanoparticle structured ZnO. For example, nanoparticle structured ZnO can be formed by a sol-gel method. In some embodiments, the concentration of ZnO in the solution can be 75 mg / mL, the speed of spinning the solution on the substrate can be 3000 rpm, and the heating temperature required in the sol-gel process can be about 300°C.

[0177] Then, a first mixed solution including a crosslinker TPE-4N3, red quantum dots with ligands, and a chlorobenzene solvent is prepared. The ligand on the surface of the red quantum dots is oleic acid. The concentration of the red quantum dots in the first mixed solution is 30 mg / mL, and the concentration of the crosslinker TPE-4N3 in the first mixed solution is 1 mg / mL. The first mixed solution is spin-coated on the electron transport layer and cured to form a solidified layer. Then, ultraviolet light is exposed, and the exposure time can be, for example, about 60 seconds. Then, development is performed with a developer having a concentration of 1% for 30 seconds to form a patterned red quantum dot single-layer pattern, as shown in Figure 38(a).

[0178] Then, a second mixed solution including a cross-linker TPE-4N3, green quantum dots with ligands, and a chlorobenzene solvent is spin-coated, wherein the ligand on the surface of the green quantum dots is 2-mercaptoethyl Boc amine. The concentration of the green quantum dots in the second mixed solution is 20 mg / mL, and the concentration of the cross-linker TPE-4N3 in the second mixed solution is 1 mg / mL. The photosensitive material is exposed to ultraviolet light, and the exposure time can be about 60 seconds, for example. Then, the photosensitive material is developed for 30 seconds using a developer having a concentration of 1% to obtain an overlay pattern of red quantum dots and green quantum dots, as shown in Figure 38(b). The hole transport layer material and the electrode material are then evaporated, and the device packaging is completed to form a light-emitting device including red quantum dots and green quantum dots.

[0179] Figure 39(a) shows the electrospectral graph of the red sub-pixel of the light-emitting device corresponding to Figure 38, and Figure 39(b) shows a photopatterned photograph of the red sub-pixel of the light-emitting device corresponding to Figure 38. As shown in Figure 39(a), when the red sub-pixel is electro-tested, as the voltage gradually increases (for example, from 4V to 8V), it is found that the electrospectral graph only has a peak at the position corresponding to the red light wavelength, and no peak at the position corresponding to the green light wavelength. This shows that there are only red quantum dots in the red sub-pixel, but no green quantum dots, and the green quantum dots have no effect on the patterned red quantum dot film layer during the photolithography process. As can be seen from Figure 39(b), the quantum dot film layer of the red sub-pixel has a good pattern shape, and the morphology is complete and undamaged.

[0180] Figure 40(a) shows the electrospectral graph of the green sub-pixel of the light-emitting device corresponding to Figure 38, and Figure 40(b) shows a photopatterned photograph of the green sub-pixel of the light-emitting device corresponding to Figure 38. As shown in Figure 40(a), when the green sub-pixel is electro-tested, as the voltage gradually increases (for example, from 4V to 8V), it is found that the electrospectral graph only has a peak at the position corresponding to the wavelength of green light, and no peak at the position corresponding to the wavelength of red light. This shows that there are only green quantum dots in the green sub-pixel, and no residual red quantum dots. As can be seen from Figure 40(b), the quantum dot light-emitting layer of the green sub-pixel has a good pattern shape, and the morphology is complete and undamaged.

[0181] In conjunction with Figures 39 and 40, in a light-emitting device including red quantum dots and green quantum dots, the quantum dot light-emitting layer includes a plurality of first quantum dot patterns, a plurality of second quantum dot patterns, a plurality of first sub-pixel regions, and a plurality of second sub-pixel regions. The first quantum dot pattern can be a red quantum dot pattern for emitting red light, the second quantum dot pattern can be a green quantum dot pattern for emitting green light, the first sub-pixel region can be a red sub-pixel region, and the second sub-pixel region can be a green sub-pixel region. The first quantum dot pattern is located only in the first sub-pixel region and not in the second sub-pixel region, and the second quantum dot pattern is located only in the second sub-pixel region and not in the first sub-pixel region. In short, the quantum dot light-emitting layer formed by using the cross-linking agent provided by the embodiment of the present disclosure has a high-quality quantum dot pattern, and each sub-pixel has no color mixing phenomenon, thereby improving the color gamut of the quantum dot electroluminescent device.

[0182] In some embodiments, in an electroluminescent device including red quantum dots, green quantum dots, and blue quantum dots, the quantum dot light-emitting layer includes a plurality of first quantum dot patterns, a plurality of second quantum dot patterns, a plurality of third quantum dot patterns, a plurality of first sub-pixel regions, a plurality of second sub-pixel regions, and a plurality of third sub-pixel regions. The first quantum dot pattern may be a red quantum dot pattern for emitting red light, the second quantum dot pattern may be a green quantum dot pattern for emitting green light, and the third quantum dot pattern may be a blue quantum dot pattern for emitting blue light. The first sub-pixel region may be a red sub-pixel region, the second sub-pixel region may be a green sub-pixel region, and the third sub-pixel region may be a blue sub-pixel region. The first quantum dot pattern is located only in the first sub-pixel region and not in the second or third sub-pixel regions. The second quantum dot pattern is located only in the second sub-pixel region and not in the first or third sub-pixel regions. The third quantum dot pattern is located only in the third sub-pixel region and not in the first or second sub-pixel regions. In short, the quantum dot light-emitting layer formed by using the cross-linking agent provided by the embodiment of the present disclosure has a high-quality quantum dot pattern, and each sub-pixel has no color mixing phenomenon, thereby improving the color gamut of the quantum dot electroluminescent device.

[0183] As a comparative example, FIG41 shows a patterned photo of a red quantum dot light-emitting layer, and the cross-linking agent used is Each cross-linking agent molecule has only two azide groups N3. The preparation method of the red quantum dot light-emitting layer is described below.

[0184] First, an electron transport layer solution is spin-coated on a substrate to form an electron transport layer.

[0185] Then, a mixed solution including a cross-linking agent, red quantum dots with ligands on the surface, and a solvent is prepared. The ligand on the surface of the red quantum dots is oleic acid, and the solvent is chlorobenzene. The concentration of the red quantum dots in the mixed solution is 20 mg / mL, and the concentration of the cross-linking agent in the mixed solution is 1 mg / mL. Then, the mixed solution is spin-coated on the electron transport layer and cured to form a solidified layer. It is then exposed to ultraviolet light, and the exposure time can be, for example, about 60 seconds. Then, the exposed red quantum dot light-emitting layer is developed using a developer. Ideally, the resulting red quantum dot pattern should be as shown in Figure 41 (a). However, the reality is that after development with the developer, the resulting red quantum dot pattern is shown in Figure 41 (b). The red quantum dot pattern cannot withstand immersion in the developer and has been basically washed away by the developer.

[0186] The phenomenon in Figure 41(b) is because the cross-linking agent There are only two azide groups N3, and the number of azide groups N3 is too small. During the cross-linking process with quantum dots, the cross-linking agent cannot provide sufficient photoinitiation efficiency, resulting in insufficient cross-linking between the quantum dots and the cross-linking agent in the exposed area, which in turn causes the formed red quantum dot light-emitting layer to have poor stability and cannot withstand immersion in the developer, thus failing to form the expected pattern shape.

[0187] As described above, in the cross-linking agents provided in various embodiments of the present disclosure, the number of azide groups N3 in each cross-linking agent molecule is greater than or equal to 3. For example, the number of azide groups N3 in each cross-linking agent molecule can be 3, 4, 5, 6, 8, or even more than a hundred. The number of azide groups N3 can ensure that the cross-linking agent has a high photoinitiation efficiency. The quantum dot light-emitting layer formed by the cross-linking agent and quantum dots provided in various embodiments of the present disclosure has high stability and can withstand immersion in a developer, thereby forming the desired pattern shape. The high stability of the quantum dot light-emitting layer provided in the embodiments of the present disclosure has been experimentally verified in the various embodiments above.

[0188] Figure 42 shows a schematic structural diagram of a light-emitting device 100. As shown in Figure 42, the light-emitting device 100 includes: a first electrode layer 101; an electron transport layer 102 located on the first electrode layer 101; a quantum dot light-emitting layer 103 located on the side of the electron transport layer 102 away from the first electrode layer 101. The quantum dot light-emitting layer 103 may be any of the quantum dot light-emitting layers described in the previous embodiments; a hole transport layer 104 located on the side of the quantum dot light-emitting layer 103 away from the first electrode layer 101; and a second electrode layer 106 located on the side of the hole transport layer 104 away from the first electrode layer 101.

[0189] The light-emitting device 100 is an electroluminescent device. Its light-emitting principle is as follows: a quantum dot light-emitting layer 103 is sandwiched between a first electrode layer 101 and a second electrode layer 106. Under the action of an electric field, the first electrode layer 101 and the second electrode layer 106 generate electrons and holes, respectively. These electrons and holes are then transferred to the quantum dot light-emitting layer 103, where they recombine into excitons, generating energy level transitions and emitting light. The light-emitting device 100 offers advantages such as high color purity, high contrast, and high stability.

[0190] In some embodiments, the light emitting device 100 may further include a hole injection layer 105 located between the hole transport layer 104 and the second electrode layer 106 .

[0191] In some embodiments, the first electrode layer 101 serves as a cathode and the second electrode layer 106 serves as an anode. In this case, the light-emitting device 100 has an inverted structure. The first electrode layer 101 and the second electrode layer 106 can be formed of various suitable materials, and the embodiments of the present disclosure are not limited thereto. For example, the material of the first electrode layer 101 can be ITO, and the material of the second electrode layer 106 can be Al.

[0192] In some alternative embodiments, the light-emitting device 100 may also be an upright structure. In this case, the stacking relationship of the various film layers of the light-emitting device 100 is as follows: an anode, a hole injection layer located on the anode; a hole transport layer located on the side of the hole injection layer away from the anode; a quantum dot light-emitting layer located on the side of the hole transport layer away from the anode; an electron transport layer located on the side of the quantum dot light-emitting layer away from the anode; and a cathode located on the side of the electron transport layer away from the anode.

[0193] The light emitting device 100 may be a top emission type or a bottom emission type.

[0194] The electron transport layer 102 can be formed of any suitable material. For example, the material of the electron transport layer 102 can be nanoparticle zinc oxide (ZnO), or metal-doped nano zinc oxide, or sol-gel (Sol-Gel) type zinc oxide (ZnO). For example, metal-doped nano zinc oxide includes zinc oxide (ZnO) doped with magnesium (Mg), aluminum (Al), zirconium (Zr) or yttrium (Y). In some embodiments, the material of the electron transport layer 102 is nanoparticle structured ZnO, for example, nanoparticle structured ZnO can be formed by a sol-gel method.

[0195] The hole transport layer 104 can be formed of any suitable material, including but not limited to carrier transport materials containing carbazole groups, carbazole derivative groups, triphenylamine groups, and triphenylamine derivative groups. In some embodiments, the material of the hole transport layer 104 can be any of 1,2,4,5-tetrakis(trifluoromethyl)benzene (TFB), polyvinylcarbazole (PVK), and poly[bis(4-phenyl)(4-butylphenyl)amine] (Poly-TPD).

[0196] The technical effects of the light-emitting device 100 can refer to the technical effects of the quantum dot light-emitting layer described in the previous embodiment, and for the sake of brevity, they will not be repeated here.

[0197] FIG43 shows a block diagram of a display device 200. The display device 200 includes multiple sub-pixels, each of which includes a light-emitting device 100. At least two of the multiple light-emitting devices 100 emit light of different colors. For example, some of the multiple light-emitting devices 100 include a red quantum dot light-emitting layer and are configured to emit red light; some of the multiple light-emitting devices 100 include a green quantum dot light-emitting layer and are configured to emit green light; and some of the multiple light-emitting devices 100 include a blue quantum dot light-emitting layer and are configured to emit blue light, thereby enabling the display device 200 to achieve full-color display.

[0198] Of course, the display device 200 also includes other components not shown, such as a driving circuit for providing an electrical signal to the light-emitting device 100 to drive the light-emitting device 100 to emit light. The display device 200 may also include a circuit board and / or an integrated circuit (IC).

[0199] The display device 200 may be any product or component based on quantum dots for display, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, or a navigator.

[0200] The display device 200 can have substantially the same technical effects as the light emitting device 100 described in the previous embodiment, and therefore, for the purpose of brevity, a repeated description will not be given here.

[0201] FIG44 shows a flow chart of a method 300 for preparing a patterned quantum dot light-emitting layer. As shown in FIG44 , the method 300 includes the following steps:

[0202] S301: Provide substrate.

[0203] The substrate may be an inorganic material, an organic material, a silicon wafer, or a composite material layer. Examples of the inorganic material include glass and metal; examples of the organic material include polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyethersulfone, or a combination thereof.

[0204] S302: applying a mixed solution on the substrate, the mixed solution including quantum dots and a crosslinker, the quantum dots including a quantum dot body and a ligand modified on the quantum dot body by coordination, the ligand including a carbon-hydrogen bond, and the crosslinker can be the crosslinker described in any of the previous embodiments.

[0205] In some embodiments, the concentration of quantum dots in the mixed solution can be approximately 20 to 35 mg / mL, for example, 20 mg / mL, 25 mg / mL, 30 mg / mL, 35 mg / mL, etc.; the concentration of the cross-linking agent in the mixed solution can be approximately 0.1 to 2.0 mg / mL, for example, 0.1 mg / mL, 0.5 mg / mL, 1.0 mg / mL, 1.5 mg / mL, 2.0 mg / mL, etc.

[0206] S303: solidifying the mixed solution to form a solidified layer.

[0207] S304: exposing and developing the solidified layer to form a patterned quantum dot light-emitting layer.

[0208] The crosslinking agent has the general formula R-(R1) n , wherein R comprises at least three reactive sites connected to R1. The group R can be or or or or or or or or other appropriate groups. Represents a polymer chain, wherein the functional groups of the polymer chain include at least one of carboxyl, hydroxyl, and aldehyde groups. The chemical formula of group R1 is Wherein any one of R2 to R6 is a conjugated group or a non-conjugated group, and the conjugated group or the non-conjugated group is connected to the reactive site on R, and the remaining groups of R2 to R6 except the group connected to the reactive site on R may be the same or different and are selected from fluorine atoms or hydrogen atoms. In the general formula R-(R1) n In the formula (a), n is a positive integer greater than or equal to 3, and the value of n is equal to the number of reaction sites on R.

[0209] In certain embodiments, the para-group R4 that can be the azido group N3 is connected with the reaction site on R, in this case, group R4 is a conjugated group or a non-conjugated group, and the remaining groups R2, R3, R5, R6 are identical or different from each other and can be respectively fluorine atoms or hydrogen atoms. In alternative embodiments, the ortho-group R2 (or R6) that can be the azido group N3 is connected with the reaction site on R, in this case, group R2 (or R6) is a conjugated group or a non-conjugated group, and the remaining groups R3, R4, R5, R6 (or R2, R3, R4, R5) are identical or different from each other and can be respectively fluorine atoms or hydrogen atoms. In alternative further embodiments, the meta-group R3 (or R5) that can be the azido group N3 is connected with the reaction site on R, in this case, group R3 (or R5) is a conjugated group or a non-conjugated group, and the remaining groups R2, R4, R5, R6 (or R2, R3, R4, R6) are identical or different from each other and can be respectively fluorine atoms or hydrogen atoms.

[0210] In some embodiments, when R is And R1 is When the general formula is R-(R1) n Where n is equal to 4, the chemical formula of the cross-linking agent can be expressed as In this chemical formula, the central parent nucleus R is tetraphenylethylene, which has four reactive sites and can therefore be linked to four groups R1. This means the crosslinker includes four azide groups N3. Because azide groups N3 have high photoinitiation efficiency, crosslinkers containing tetrasubstituted azide groups N3 exhibit a high degree of crosslinking. Using this crosslinker can improve the stability of the quantum dot light-emitting layer.

[0211] The selection of the crosslinker group R4 mainly considers factors such as solubility, the source of raw materials, and the difficulty of post-processing. In terms of solubility, based on the principle of like dissolves like between molecules, the crosslinker and quantum dots are ensured to have good compatibility. For example, when the solvent of the quantum dots contains an ester group, the crosslinker group R4 can be selected as an ester group. When the solvent of the quantum dots contains an amide group, the crosslinker group R4 can be selected as an amide group. When the solvent of the quantum dots contains a carbon-nitrogen double bond, the crosslinker group R4 can be selected as a carbon-nitrogen double bond. When the solvent of the quantum dots contains a carbon-carbon double bond, the crosslinker group R4 can be selected as a carbon-carbon double bond. When the solvent of the quantum dots contains an ether group, the crosslinker group R4 can be selected as an ether group.

[0212] In some embodiments, the chemical formula of the cross-linking agent can be Or it could be Or it could be Or it could be Or it could be

[0213] In some embodiments, step S304 may further include the following sub-steps: exposing the solidified layer using a mask plate, allowing ultraviolet light to pass through the mask plate to expose the solidified layer, and causing the cross-linking agent to react with the ligands on the surface of the quantum dots under ultraviolet light; and developing the cross-linked solidified layer using a developer, wherein the portion of the solidified layer located in the non-exposed area is dissolved by the developer, and the portion of the solidified layer located in the exposed area is not dissolved by the developer, so as to form a patterned quantum dot light-emitting layer.

[0214] The quantum dots provided in the embodiments of the present disclosure are negative-type quantum dot materials. Specifically, during the preparation process, a mixed solution including quantum dots and a cross-linking agent is cured to form a cured layer. Under light radiation, the chemical composition of the exposed portion of the cured layer changes, while the chemical composition of the unexposed portion does not change. The unexposed portion of the cured layer can subsequently be dissolved in a specific developer, while the exposed portion is not dissolved by the developer, thereby forming a patterned quantum dot light-emitting layer. Therefore, during the preparation, the quantum dot film with photosensitive properties can be directly exposed and developed to obtain a patterned quantum dot light-emitting layer, without the use of photoresist and without the need to etch the quantum dot light-emitting layer.

[0215] In method 100, because the R groups in the crosslinker have at least three reactive sites capable of connecting with R groups, each R group can connect to at least three R groups. Since each R group includes at least one azide group N3, the crosslinker includes at least three azide groups N3. Because the azide groups N3 have high photoinitiation efficiency and relatively low exposure doses, and because the azide groups N3 in the crosslinker can generate nitrogen carbene radicals under UV exposure conditions, they are highly reactive. Therefore, under UV exposure conditions, the crosslinker can undergo nitrogen-hydrogen insertion reactions with the carbon-hydrogen bonds of the quantum dot ligands, forming a crosslinked quantum dot light-emitting layer. The resulting quantum dot light-emitting layer is highly stable. When exposed to a developer, the exposed portion of the quantum dot light-emitting layer is not damaged by the developer, allowing the desired pattern to be formed intact. Simultaneously, the unexposed portion of the quantum dot light-emitting layer can be rinsed away by the developer, leaving no residue, thus avoiding color mixing caused by residual quantum dots. This solves the problem of residual quantum dots while also producing a high-quality quantum dot pattern.

[0216] It will be understood that the term "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.

[0217] The term "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0218] 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, where the acceptable range of deviation is 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).

[0219] It will be understood that although the terms first, second, third, etc. may be used to describe various elements, components, areas, layers and / or parts in this article, these elements, components, areas, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer or part from another element, component, area, layer or part. Therefore, the first element, component, area, layer or part discussed above can be referred to as the second element, component, area, layer or part without departing from the teachings of the present disclosure.

[0220] Spatially relative terms such as "row," "column," "under," "above," "left," "right," and the like may be used herein to describe the relationship of one element or feature to another element or feature as illustrated in the figures for ease of description. It will be understood that these spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figure is flipped, the element described as "under other elements or features" will be oriented as "above other elements or features." Thus, the exemplary term "under" can encompass both orientations of above and below. The device can be oriented otherwise (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein are interpreted accordingly. In addition, it will also be understood that when a layer is referred to as "between two layers," it can be the only layer between the two layers, or one or more intermediate layers may also be present.

[0221] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "one", "an" and "the" are intended to also include the plural forms, unless the context clearly indicates otherwise. It will be further understood that the terms "include" and / or "comprise" when used in this specification specify the presence of the features, wholes, steps, operations, elements and / or parts, but do not exclude the presence of one or more other features, wholes, steps, operations, elements, parts and / or their groups or add one or more other features, wholes, steps, operations, elements, parts and / or their groups. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In the description of this specification, the description of the reference terms "one embodiment", "another embodiment" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily need to be directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. Furthermore, those skilled in the art may combine different embodiments or examples and features of different embodiments or examples described in this specification without mutual contradiction.

[0222] It will be understood that when an element or layer is referred to as being “on,” “connected to,” “coupled to,” or “adjacent to” another element or layer, it can be directly on, directly connected to, directly coupled to, or directly adjacent to another element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to,” “directly coupled to,” or “directly adjacent to” another element or layer, no intervening elements or layers are present. However, in no case should “on” or “directly on” be interpreted as requiring that one layer completely cover the underlying layer.

[0223] Embodiments of the present disclosure are described herein with reference to schematic illustrations (and intermediate structures) of idealized embodiments of the present disclosure. Because of this, variations in the illustrated shapes, for example as a result of manufacturing techniques and / or tolerances, should be expected. Therefore, embodiments of the present disclosure should not be interpreted as being limited to the specific shapes of the regions illustrated herein, but should include shape deviations, for example, due to manufacturing. Therefore, the regions illustrated in the figures are schematic in nature, and their shapes are not intended to illustrate the actual shape of the regions of the device and are not intended to limit the scope of the present disclosure.

[0224] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present disclosure belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the relevant art and / or the context of this specification, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0225] As will be appreciated by those skilled in the art, although the various steps of the method of the present disclosure are described in a particular order in the accompanying drawings, this does not require or imply that the steps must be performed in that particular order unless the context clearly indicates otherwise. Additionally or alternatively, multiple steps may be combined into a single step and / or a single step may be broken down into multiple steps and performed. In addition, other method steps may be inserted between steps. An inserted step may represent an improvement to a method such as that described herein, or may be unrelated to the method. In addition, a given step may not be fully completed before the next step begins.

[0226] 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 can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in 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 crosslinking agent having the general formula R-(R1) n , where R includes at least three reactive sites connected to R1, and R is selected from any one of the following groups: Among them represents a polymer chain, and the functional groups of the polymer chain include at least one of a carboxyl group, a hydroxyl group, and an aldehyde group, and wherein, R1 includes an azide group N3, n is a positive integer greater than or equal to 3, and the value of n is equal to the number of the reaction sites.

2. The crosslinking agent according to claim 1, wherein The chemical formula of the said R1 is wherein, any one of the groups R2 to R6 is a conjugated group or a non-conjugated group, the conjugated group or the non-conjugated group is connected to the reaction site on the R, and wherein, the remaining groups of R2 to R6 except the group connected to the reaction site on the R are the same or different from each other, and are respectively selected from a fluorine atom or a hydrogen atom.

3. The crosslinking agent according to claim 2, wherein The non-conjugated group includes at least one of an ester group, an amide group, an ether group, an imine group, and a carbon-nitrogen double bond.

4. The crosslinking agent according to claim 2, wherein The conjugated group includes a carbon-carbon double bond.

5. The crosslinking agent according to any one of claims 2-4, wherein, The chemical formula of the said R1 is wherein R4 is connected to the reaction site on the said R.

6. The crosslinking agent according to claim 5, wherein, n is equal to 4, and the chemical formula of the cross-linking agent is 7. The crosslinking agent according to claim 6, wherein The chemical formula of the crosslinking agent is 8. A quantum dot, comprising a quantum dot body and a ligand coordinated on the quantum dot body, wherein, The ligand includes a carbon-hydrogen bond, and the ligand is configured to undergo a cross-linking reaction with the cross-linking agent according to any one of claims 1-7 under light radiation.

9. The quantum dot according to claim 8, wherein, The ligand is selected from any one of oleylamine, isooctyl mercaptan, mercaptoacetic acid, mercaptopropionic acid, oleic acid, and 2-mercaptoethyl Boc amine.

10. The quantum dot according to claim 9, wherein, The quantum dots are configured to emit red light or blue light, and the ligand is oleic acid.

11. The quantum dot according to claim 9, wherein, The quantum dots are configured to emit green light, and the ligand is 2-mercaptoethyl Boc amine.

12. A quantum dot composition, comprising a mixed solution, wherein, The mixed solution includes the quantum dots according to any one of claims 8-11, the cross-linking agent according to any one of claims 1-7, and a solvent, wherein the concentration of the quantum dots in the mixed solution is about 20-35 mg / mL, and the concentration of the cross-linking agent in the mixed solution is about 0.1-2.0 mg / mL.

13. The quantum dot composition according to claim 12, wherein, The solvent is selected from any one of propylene glycol methyl ether acetate, toluene, chlorobenzene, octane, water, and alcohol solvents.

14. A quantum dot light-emitting layer includes a plurality of quantum dots, wherein, At least some of the plurality of quantum dots include a quantum dot body and a ligand coordinated on the quantum dot body, and the quantum dot light-emitting layer is formed by cross-linking the quantum dots having the ligand and the cross-linking agent according to any one of claims 1-7.

15. The quantum dot light-emitting layer according to claim 14, wherein, The chemical formula of the quantum dot light-emitting layer is R-(R1'-R7-QD) n , where QD represents a quantum dot, R7 represents the ligand and includes a carbon-hydrogen bond, and R1' represents the group obtained by replacing the azide group N3 of the group R1 with the group NH.

16. The quantum dot light-emitting layer according to claim 15, wherein, The chemical formula of the quantum dot light-emitting layer is wherein R4 is a conjugated group or a non-conjugated group, and R2, R3, R5, and R6 are the same as or different from each other and are each independently selected from a fluorine atom or a hydrogen atom.

17. The quantum dot light-emitting layer according to claim 16, wherein, The quantum dot light-emitting layer is configured to emit red light or blue light, and the chemical formula of the quantum dot light-emitting layer is R7 is oleic acid.

18. The quantum dot light-emitting layer according to claim 16, wherein, The quantum dot light-emitting layer is configured to emit green light, and the chemical formula of the quantum dot light-emitting layer is R7 is 2-mercaptoethyl Boc amine.

19. The quantum dot light-emitting layer according to any one of claims 14-16, wherein, The quantum dot light-emitting layer includes a plurality of first quantum dot patterns, a plurality of second quantum dot patterns, a plurality of first sub-pixel regions, and a plurality of second sub-pixel regions. The first quantum dot patterns are configured to emit red light, the second quantum dot patterns are configured to emit green light. The first quantum dot patterns are only located in the first sub-pixel regions and not in the second sub-pixel regions. The second quantum dot patterns are only located in the second sub-pixel regions and not in the first sub-pixel regions.

20. The quantum dot light-emitting layer according to claim 19, wherein, The quantum dot light-emitting layer further includes a plurality of third quantum dot patterns and a plurality of third sub-pixel regions. The third quantum dot patterns are configured to emit blue light. The first quantum dot patterns are only located in the first sub-pixel regions and not in the second sub-pixel regions and the third sub-pixel regions. The second quantum dot patterns are only located in the second sub-pixel regions and not in the first sub-pixel regions and the third sub-pixel regions. The third quantum dot patterns are only located in the third sub-pixel regions and not in the first sub-pixel regions and the second sub-pixel regions.

21. A light-emitting device, comprising: A first electrode layer; An electron transport layer, located on the first electrode layer; The quantum dot light-emitting layer according to any one of claims 14-20 is located on a side of the electron transport layer away from the first electrode layer; The hole transport layer is located on a side of the quantum dot light-emitting layer away from the first electrode layer; And The second electrode layer is located on a side of the hole transport layer away from the first electrode layer.

22. The light-emitting device according to claim 21, wherein, The electron transport layer is nanoparticles.

23. A display device, comprising a plurality of light-emitting devices according to claim 21 or 22, wherein, At least two of the plurality of light-emitting devices are configured to emit light of different colors.

24. A method for preparing a patterned quantum dot light-emitting layer, comprising: Providing a substrate; Applying a mixed solution on the substrate, the mixed solution comprising quantum dots and a crosslinking agent, the quantum dots comprising a quantum dot body and ligands coordinated on the quantum dot body, the ligands comprising carbon-hydrogen bonds, and the crosslinking agent being the crosslinking agent according to any one of claims 1-7; Curing the mixed solution to form a cured layer; And Exposing and developing the cured layer to form a patterned quantum dot light-emitting layer.

25. The method according to claim 24, wherein, Exposing and developing the cured layer includes: Exposing the cured layer by using a mask plate to allow ultraviolet light to pass through the mask plate to expose the cured layer, and under ultraviolet light irradiation, the crosslinking agent reacts with the ligands on the surface of the quantum dots to undergo a crosslinking reaction; and Developing the crosslinked cured layer with a developer, and a portion of the cured layer located in a non-exposed area is dissolved by the developer, and a portion of the cured layer located in an exposed area is not dissolved by the developer to form the patterned quantum dot light-emitting layer.

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