Quantum dot layer patterning method, quantum dot layer, light-emitting device and display device

Abstract

The present disclosure provides a quantum dot layer patterning method, comprising: forming a film layer on a substrate layer, the film layer comprising quantum dots, an initial ligand coordinated with the quantum dots, a photo-induced acid generator and a photo-crosslinking agent, the molecule of the initial ligand comprising an acid response group capable of reacting with an acid, the molecule of the photo-induced acid generator comprising an acid-responsive group capable of reacting with an acid, and the molecule of the photo-crosslinking agent comprising an acid-responsive group capable of reacting with an acid; the molecule of the photo-crosslinking agent comprises at least two crosslinking groups capable of being subjected to crosslinking reaction with the initial ligand; irradiating a quantum dot retaining area in the film layer by using ultraviolet light, obtaining a polarized ligand in the quantum dot retaining area, and enabling the initial ligand to react with the cross-linking group; and removing the part, which is not irradiated by the ultraviolet light, in the film layer by using a non-polar developing solution to form a patterned quantum dot layer. In addition, the invention also relates to the patterned quantum dot layer obtained by using the method, and also relates to a quantum dot electroluminescent device comprising the patterned quantum dot layer, and a display device comprising the quantum dot electroluminescent device.

Description

Quantum dot layer patterning method, quantum dot layer, light-emitting device and display device Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular, to a method for patterning a quantum dot layer, a patterned quantum dot layer obtained by using the method, a quantum dot electroluminescent device including the patterned quantum dot layer, and a display device including the quantum dot electroluminescent device. Background Art

[0002] Quantum dot light-emitting diode (QLED) displays are a new display technology based on organic light-emitting diode (OLED) displays. QLED uses a quantum dot layer as its light-emitting layer. The principle behind QLEDs is that holes and electrons are injected into the quantum dot layer through a hole / electron transport layer, where they recombine and emit light. Compared to OLEDs, QLEDs offer advantages such as high color saturation, a wide color gamut, a narrow emission peak, and excellent stability.

[0003] In related technologies, photolithography is generally used to pattern the quantum dot layer. However, when using photolithography to pattern the quantum dot layer for the production of full-color devices, some quantum dots in the non-exposed areas will always remain in the pixel area during the development process, resulting in color mixing when other sub-pixels are subsequently pixelated, thereby reducing the color gamut of the quantum dot electroluminescent device.

[0004] Summary of the Invention

[0005] According to a first aspect of the present disclosure, a method for patterning a quantum dot layer is provided, comprising: forming a film layer comprising quantum dots, initial ligands coordinated with the quantum dots, a photoacid generator, and a photocrosslinker on a substrate layer, wherein the molecules of the initial ligands include an acid-responsive group capable of reacting with an acid, and the molecules of the photocrosslinker include at least two crosslinking groups capable of undergoing a crosslinking reaction with the initial ligands; irradiating a quantum dot retention region in the film layer with ultraviolet light, so that in the quantum dot retention region, the initial ligands react with the acid generated by the photoacid generator, causing the molecules of the initial ligands to be polarized into polar molecules, thereby generating polarized ligands, and the initial ligands react with the crosslinking groups; and removing portions of the film layer not irradiated by the ultraviolet light using a non-polar developer to form a patterned quantum dot layer.

[0006] According to some exemplary embodiments, the quantum dot layer patterning method further includes, during the period when the ultraviolet light irradiates the quantum dot retention region, reacting the polarized ligand with the cross-linking group in the quantum dot retention region.

[0007] According to some exemplary embodiments, the quantum dot layer patterning method further includes, during the period when the ultraviolet light irradiates the quantum dot retention region, reacting the photoacid generator with a crosslinking group of the photocrosslinker in the quantum dot retention region.

[0008] According to some exemplary embodiments, the component of the initial ligand is 2-mercaptoethyl BOC amine, the acid-responsive group is a t-BOC group, and the cross-linking group is a diazonaphthoquinone group or a benzophenone group.

[0009] According to some exemplary embodiments, the chemical formula of the initial ligand is R1-acetal-R2, wherein R1 is one of a thiol group, a carboxyl group, and an amino group, R2 is an alkyl group or an aromatic group, the acid-responsive group is an acetal; and the cross-linking group is a diazonaphthoquinone group or a benzophenone group.

[0010] According to some exemplary embodiments, when the crosslinking group is a diazonaphthoquinone group, the component of the photocrosslinking agent is a tri-substituted diazonaphthoquinone derivative.

[0011] According to some exemplary embodiments, the mass of the photoacid generator is within 20% of the mass of the quantum dots, and the mass of the photocrosslinker is within 20% of the mass of the quantum dots.

[0012] According to some exemplary embodiments, the quantum dot layer patterning method further includes: providing a substrate; and spin-coating a zinc oxide layer on the substrate to form the base layer, wherein the zinc oxide layer is prepared by a sol-gel method.

[0013] According to some exemplary embodiments, the quantum dot layer patterning method further includes: providing a substrate; and sputtering a zinc oxide layer on the substrate to form the base layer.

[0014] According to some exemplary embodiments, irradiating the quantum dot retention area in the film layer with ultraviolet light includes: irradiating a mask that blocks the film layer with the ultraviolet light, wherein the mask includes a light-transmitting area and a light-blocking area, and the light-transmitting area corresponds to the quantum dot retention area.

[0015] According to some exemplary embodiments, the removing of the portion of the film layer not irradiated by the ultraviolet light using a non-polar developer includes: performing a first development on the film layer using a first non-polar developer having a first concentration; and after the first development, performing a second development on the film layer using a second non-polar developer having a second concentration, wherein the second concentration is greater than the first concentration.

[0016] According to a second aspect of the present disclosure, a patterned quantum dot layer is provided, comprising at least one sub-pixel region, wherein each sub-pixel region comprises: a sub-pixel quantum dot; an initial ligand coordinated with the sub-pixel quantum dot; and a polarized ligand coordinated with the sub-pixel quantum dot, wherein the polarized ligand is generated by reacting the initial ligand with an acid generated by a photoacid generator, causing the molecules of the initial ligand to be polarized into polar molecules; wherein at least two sub-pixel quantum dots are cross-linked together through a reaction between the initial ligand and a cross-linking group of a photocross-linking agent.

[0017] According to some exemplary embodiments, at least two sub-pixel quantum dots are further cross-linked together through a reaction between the polarized ligand and a cross-linking group of the photo-cross-linking agent.

[0018] According to some exemplary embodiments, each of the sub-pixel regions further includes: the photoacid generator, the photocrosslinker, and a product obtained by a reaction between the photoacid generator and the photocrosslinker.

[0019] According to some exemplary embodiments, the component of the initial ligand is 2-mercaptoethyl BOC amine, the component of the polarized ligand is 2-aminoethanethiol, and the cross-linking group is a diazonaphthoquinone group or a benzophenone group.

[0020] According to some exemplary embodiments, the chemical formula of the initial ligand is Wherein, R1 is one of thiol, carboxyl and amino groups, R2 is an alkyl group or an aromatic group, and the chemical formula of the polarized ligand is The crosslinking group is a diazonaphthoquinone group or a benzophenone group.

[0021] According to some exemplary embodiments, when the crosslinking group is a diazonaphthoquinone group, the component of the photocrosslinking agent is a tri-substituted diazonaphthoquinone derivative.

[0022] According to some exemplary embodiments, the patterned quantum dot layer has a thickness between 15 nm and 30 nm.

[0023] According to some exemplary embodiments, the patterned quantum dot layer includes at least two sub-pixel regions, each sub-pixel region is configured to emit light of a different color, and each sub-pixel region includes sub-pixel quantum dots having different quantum dot compositions.

[0024] According to some exemplary embodiments, the patterned quantum dot layer includes at least two sub-pixel regions, each sub-pixel region is configured to emit light of a different color, and each sub-pixel region includes sub-pixel quantum dots having different quantum dot sizes.

[0025] According to the third aspect of the present disclosure, a quantum dot electroluminescent device is provided, comprising: a cathode, an electron transport layer, the patterned quantum dot layer according to the second aspect of the present disclosure and its exemplary embodiments, a hole transport layer and an anode stacked in sequence on a substrate; or comprising: an anode, a hole transport layer, the patterned quantum dot layer according to the second aspect of the present disclosure and its exemplary embodiments, an electron transport layer and a cathode stacked in sequence on a substrate.

[0026] According to some exemplary embodiments, the electron transport layer is a zinc oxide layer.

[0027] According to some exemplary embodiments, a content of organic components in the zinc oxide layer is greater than 0 and less than a content of organic components in the patterned quantum dot layer.

[0028] According to some exemplary embodiments, the content of organic components in the zinc oxide layer is 0.

[0029] According to a fourth aspect of the present disclosure, a display device is provided, which includes the quantum dot electroluminescent device according to the third aspect of the present disclosure and each exemplary embodiment thereof. 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 schematically illustrates the process of patterning a quantum dot layer and the problems that exist in the related art;

[0032] FIG2 schematically illustrates the color mixing in the sub-pixels obtained by the patterning operation of the quantum dot layer shown in FIG1 ;

[0033] FIG3 schematically illustrates a method for patterning a quantum dot layer according to an exemplary embodiment of the present disclosure in the form of a flow chart;

[0034] FIG4 schematically illustrates a photochemical reaction process in the quantum dot layer patterning method shown in FIG3 according to an exemplary embodiment of the present disclosure;

[0035] FIG5 schematically illustrates a photochemical reaction process in the quantum dot layer patterning method shown in FIG3 according to another exemplary embodiment of the present disclosure;

[0036] FIG6 schematically illustrates a cross-linking reaction between another cross-linking group and a ligand molecule according to an exemplary embodiment of the present disclosure;

[0037] FIG7 schematically illustrates a development process in the quantum dot layer patterning method shown in FIG3 according to an exemplary embodiment of the present disclosure;

[0038] FIG8 schematically illustrates a development effect when the substrate layer is a SG ZnO layer according to an exemplary embodiment of the present disclosure;

[0039] FIG9 schematically illustrates a development effect when the substrate layer is a sputtered ZnO layer according to an exemplary embodiment of the present disclosure;

[0040] FIG10 schematically shows a method for improving the molecules of a photocrosslinker according to an exemplary embodiment of the present disclosure;

[0041] FIG11 schematically shows an exemplary synthesis route of a photocrosslinker according to an exemplary embodiment of the present disclosure;

[0042] FIG12 schematically shows an electrospectroscopy spectrum of a patterned quantum dot layer obtained by a quantum dot layer patterning method according to an exemplary embodiment of the present disclosure;

[0043] FIG13 schematically illustrates, in block diagram form, a structure of a quantum dot electroluminescent device according to an exemplary embodiment of the present disclosure;

[0044] FIG14 schematically shows the test results of a quantum dot electroluminescent device obtained according to an exemplary embodiment of the present disclosure;

[0045] FIG15 schematically illustrates, in block diagram form, the structure of another quantum dot electroluminescent device according to an exemplary embodiment of the present disclosure;

[0046] FIG16 schematically illustrates a structure of a display device according to an exemplary embodiment of the present disclosure in the form of a block diagram;

[0047] FIG. 17 schematically illustrates, in block diagram form, a structure of another display device according to an exemplary embodiment of the present disclosure.

[0048] 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 features are indicated by identical or similar reference numerals. DETAILED DESCRIPTION

[0049] Various exemplary embodiments of the present disclosure are described below in conjunction with the accompanying drawings so that those skilled in the art can fully understand and implement the technical solutions according to the present disclosure.

[0050] Refer to Figure 1, which schematically illustrates the process of patterning a quantum dot layer in the related art and the problems that exist. As shown in Figure 1, a zinc oxide (ZnO) layer is provided on a glass substrate, a quantum dot layer is provided on the ZnO layer, and a mask is provided above the quantum dot layer. The mask includes a light-transmitting area and a light-blocking area. During the exposure phase, ultraviolet light (UV light) is irradiated through the mask, exposing the portion of the quantum dot layer corresponding to the light-transmitting area of ​​the mask. During the development phase, a developer is applied to the quantum dot layer, removing the unexposed portions of the quantum dot layer while retaining the exposed portions. This achieves patterning of the quantum dot layer. However, due to factors such as van der Waals forces between the quantum dot layer and the ZnO layer, some residual quantum dots may remain in the unexposed portions of the quantum dot layer after the development process. These residual quantum dots can cause color mixing when the next sub-pixel with a different color is produced, significantly reducing the color gamut of the quantum dots.

[0051] Referring to Figure 2 and in combination with Figure 1, it schematically illustrates the color mixing in the sub-pixels obtained by the patterning operation of the quantum dot layer shown in Figure 1. The electrospectral diagram shown in Figure 2 is for a quantum dot layer formed in the following manner, namely: according to the patterning process shown in Figure 1, first a film layer containing red quantum dots is coated on the ZnO layer, the film layer containing red quantum dots is exposed in position (for example, a 30-second exposure), then developed with a developer, then a film layer containing blue quantum dots is coated on the ZnO layer, the film layer containing blue quantum dots is exposed in position, then developed with a developer, the unexposed portion of the above film layer is removed, and finally a hole transport layer and a metal aluminum electrode are evaporated. Figure 2 is an electrospectral diagram obtained by electrospectral testing of the blue sub-pixel obtained in the above manner. As shown in Figure 2, as the voltage increases (for example, from 4V to 8V), there is an obvious spectral peak caused by the red quantum dots (that is, the spectral peak of the residual red quantum dots) in the electrospectral spectrum of the blue sub-pixel, which means that the obtained blue sub-pixel has mixed colors with red.

[0052] The residual quantum dots cause color mixing with the already completed sub-pixels (e.g., red sub-pixels) when producing the next sub-pixel (e.g., green or blue sub-pixels) in the production of full-color devices after completing the production of one color sub-pixel (e.g., red sub-pixel). This significantly reduces the color gamut of the quantum dots and weakens the advantages of quantum dots as electroluminescent materials. Currently, related art teaches that strong developers (e.g., sodium hydroxide developer, potassium hydroxide developer, etc.) can be used during the development process, but this often removes the quantum dots in the exposed area, resulting in damage to the patterned quantum dot layer.

[0053] 3 , which schematically illustrates a method for patterning a quantum dot layer according to an exemplary embodiment of the present disclosure in the form of a flow chart. As shown in FIG3 , the method 100 for patterning a quantum dot layer includes steps 110 , 120 , and 130 .

[0054] In step 110, a film layer including quantum dots, initial ligands coordinated with the quantum dots, a photoacid generator, and a photocrosslinker is formed on a substrate layer provided on a substrate, wherein the molecules of the initial ligands include an acid-responsive group capable of reacting with an acid, and the molecules of the photocrosslinker include at least two crosslinking groups capable of undergoing a crosslinking reaction with the initial ligands.

[0055] As an exemplary embodiment, quantum dots may include any one or more of group III-V quantum dots, group IV quantum dots, group II-VI quantum dots, core-shell quantum dots, and alloy quantum dots. Specifically, the above-mentioned quantum dots may be any one or more 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. In other words, all currently available quantum dots can be used for the technical solutions taught in this disclosure, and they may be a single quantum dot or a composite of two or more quantum dots. The specific selection of quantum dots can be selected according to the desired luminescent color, etc., and will not be repeated here.

[0056] The initial ligand can contain existing groups that are easy to coordinate with quantum dots, such as amino, sulfhydryl, hydroxyl, polyamino, polysulfhydryl, polyhydroxy, phosphorus, oxyphosphorus, organophosphorus, thioether, etc., so as to coordinate with the quantum dots. In addition, the molecule of the initial ligand must include an acid-responsive group that can react with acid. In an exemplary embodiment, the component of the initial ligand can be 2-mercaptoethyl BOC amine, whose chemical formula is as follows:

[0057] Among them, the acid-responsive group that can react with acid is t-BOC group. Under UV light irradiation, the acid generated by the photoacid generator can catalyze the deprotection of t-BOC group, thereby exposing the amino group to generate 2-aminoethanethiol (its chemical formula becomes This polarizes the molecules of the initial ligand (i.e., changes them from non-polar molecules to polar molecules), thereby generating polarized ligands. At the same time, the free radicals generated by the cross-linking groups of the photocrosslinker can undergo CH insertion reactions and / or NH insertion reactions with the initial ligands, causing the quantum dots to be cross-linked, thereby forming a more stable film layer. It should be noted that polar molecules refer to molecules in which the centers of positive and negative charges do not overlap, resulting in uneven and asymmetric charge distribution from the perspective of the entire molecule. Such molecules are called polar molecules. Conversely, they are non-polar molecules.

[0058] In another exemplary embodiment, the component of the ligand may be a compound including acetal, the chemical formula of which is R1-acetal-R2, the chemical formula of which is as follows:

[0059] Wherein, R1 can be one of a thiol group, a carboxyl group, and an amino group, R2 is an alkyl group or an aromatic group, and the acid-responsive group capable of reacting with an acid is an acetal group. The aromatic group can include any one or more of the following groups: phenyl, alkylphenyl, thienyl, pyrimidine, anilino, naphthalene, phenoxy, etc. As shown below, Chemical Formulas 2a, 2b, and 2c respectively represent the chemical formulas when R1 in Chemical Formula 2 is a thiol group, a carboxyl group, and an amino group.

[0060] Under UV light, the acid generated by the photoacid generator can deprotect the carboxyl structure of the acetal group, thereby generating a hydroxyl group, thereby polarizing the ligand molecule. The reaction equation for this reaction is shown below.

[0061] The photoacid generator (PAG) can be any suitable photoacid generator currently available in the relevant art, as long as it can generate acid under UV light irradiation, and this disclosure is not limited thereto. As an exemplary embodiment, a photoacid generator can be 2,4-bis(trichloromethyl)-6-p-methoxyphenyl-S-triazine (MBT), which has the following chemical formula:

[0062] The photocrosslinking agent molecule must include at least two crosslinking groups that can undergo a crosslinking reaction with the above-mentioned initial ligand. It should be understood that the crosslinking group can be any suitable photoresponsive crosslinking reaction group that can undergo a crosslinking reaction under the irradiation of UV light. As an exemplary embodiment, the crosslinking group can be a diazonaphthoquinone group (chemical formula ) or benzophenone group (chemical formula is Under UV light irradiation, both the diazonaphthoquinone group and the benzophenone group can generate highly active carbene radicals, which can undergo C—H insertion reactions and NH insertion reactions, thereby being able to undergo cross-linking reactions with the molecules of the initial ligand.

[0063] In an exemplary embodiment, the photocrosslinking agent is a trisubstituted diazonaphthoquinone derivative, and its chemical formula is as follows:

[0064] Wherein, the group R is a diazonaphthoquinone group. It should be understood that, as required, the group R in Chemical Formula 4 may also be a benzophenone group instead.

[0065] In one exemplary embodiment, the mass of the photoacid generator can be within 20% of the mass of the quantum dots, and the mass of the photocrosslinker can also be within 20% of the mass of the quantum dots. In another exemplary embodiment, if the ligand molecule includes an acid-responsive group with a relatively low bond energy (e.g., an acetal group), so that only a smaller amount of acid is required to achieve the deprotection effect, the mass of the required photoacid generator can be correspondingly reduced, for example, to 0.5% to 5% of the mass of the quantum dots.

[0066] Depending on actual needs (e.g., whether the device structure is inverted or upright), the substrate layer can be implemented as a functional film layer such as an electron transport layer (e.g., a ZnO layer) or a hole transport layer (e.g., a TFB layer). The following description will be based on a ZnO layer (implemented as an electron transport layer) as the substrate layer.

[0067] Continuing with FIG3 , in step 120 , ultraviolet light is used to irradiate the quantum dot retention region in the film layer. In this region, the initial ligand reacts with the acid generated by the photoacid generator, polarizing the initial ligand molecules into polar molecules, thereby generating polarized ligands, and the initial ligands react with the crosslinking groups. Thus, under UV irradiation, a complex photochemical reaction occurs in the exposed region of the film layer, including: the acid generated by the photoacid generator reacts with the acid-responsive groups in the initial ligands, polarizing the initial ligand molecules, thereby generating polarized ligands; and the crosslinking groups of the photocrosslinker generate corresponding free radicals, causing the initial ligands of the quantum dots to undergo a crosslinking reaction with the photocrosslinker, thereby crosslinking the quantum dots. This forms a more stable film layer in the exposed region.

[0068] Referring to FIG4 , in conjunction with FIG3 , a photochemical reaction process in the quantum dot layer patterning method shown in FIG3 is schematically shown according to an exemplary embodiment of the present disclosure. As a non-limiting example, the component of the initial ligand is 2-mercaptoethyl BOC amine, and the crosslinking group included in the photocrosslinker is a diazonaphthoquinone group. As shown in FIG4 , the photochemical reaction process in the first row shows that PAG generates acid (i.e., H + ), which can catalyze the deprotection of the t-BOC group included in the molecule of the initial ligand, thereby exposing the amino group and generating 2-aminoethanethiol, polarizing the molecule of the initial ligand, thereby generating a polarized ligand; the photochemical reaction process in the second row shows that the diazonaphthoquinone group generates a highly active carbene radical (i.e., c: in the figure) under the irradiation of UV light, and the carbene radical can undergo a C-H insertion reaction with the molecule of the initial ligand; the photochemical reaction process in the third row shows that the molecule of the photocrosslinker includes three diazonaphthoquinone groups, which generate highly active carbene radicals under the irradiation of UV light, and undergo a crosslinking reaction shown in the second row with the initial ligand coordinated with the diazonaphthoquinone carbene radical, thereby crosslinking the quantum dots together. Because the quantum dots are crosslinked together, the resulting quantum dot layer is more stable, and thus can be developed using a strong non-polar developer.

[0069] Referring to FIG5 , and also in conjunction with FIG3 , a schematic diagram of the photochemical reaction process in the quantum dot layer patterning method shown in FIG3 is shown according to another exemplary embodiment of the present disclosure. As a non-limiting example, the initial ligand component is still 2-mercaptoethyl BOC amine, and the crosslinking group included in the photocrosslinker is still a diazonaphthoquinone group. As shown in Figure 5, the content displayed is roughly similar to that displayed in Figure 4, except for the following three aspects: First, the photochemical reaction process in the second row of Figure 5 also shows that under the irradiation of UV light, the t-BOC group in the ligand molecule first reacts with the acid generated by PAG, so that the ligand molecule is polarized (i.e., 2-aminoethanethiol is generated), thereby generating a polarized ligand, and then the polarized ligand molecule also undergoes a cross-linking reaction with the diazonaphthoquinone group included in the photocrosslinker; Second, the photochemical reaction process in the fourth row of Figure 5 shows that the photocrosslinker molecule includes three diazonaphthoquinone groups, which generate highly active carbene radicals under the irradiation of UV light, and undergo the cross-linking reaction shown in the second row with the polarized ligand coordinated to the quantum dots and the carbene radicals of diazonaphthoquinone, thereby cross-linking the quantum dots together; Third, under the irradiation of UV light, the PAG (e.g., MBT) molecules can also undergo a cross-linking reaction with the diazonaphthoquinone group in the photocrosslinker, thereby cross-linking together. Therefore, in the photochemical reaction process shown in Figure 5, due to the presence of more different types of cross-linking reactions, the degree of cross-linking of the quantum dots in the exposed area of ​​the film layer is higher, thereby improving the stability of the resulting quantum dot layer. In addition, due to the presence of other cross-linking reaction products in the film layer (such as the product obtained by the cross-linking reaction between the above-mentioned PAG and the diazonaphthoquinone group), the stability of the film layer as a whole is further enhanced. Of course, it should be noted that the molecules of the photoacid generator composed of MBT have fewer carbon-hydrogen bonds. Therefore, when the concentration of MBT is low, the probability of it undergoing a cross-linking reaction with the photocrosslinker will be relatively low, so that in some cases, the reaction products of MBT and the photocrosslinker may not be present in the illuminated area of ​​the film layer.

[0070] Referring to Figure 6, which schematically illustrates another cross-linking reaction between a cross-linking group and a ligand molecule according to an exemplary embodiment of the present disclosure, wherein the cross-linking group of the photocrosslinker shown is a benzophenone group. As shown in the photochemical reaction formula in the first row of Figure 6, under the irradiation of UV light, the benzophenone group generates a carbene radical (i.e., c: in the figure) and an oxygen radical (i.e., O: in the figure). The carbene radical can undergo a CH insertion reaction with the molecule of the ligand (e.g., 2-mercaptoethyl BOC amine), thereby undergoing a cross-linking reaction with the ligand molecule. In the photochemical reaction formula in the second row of Figure 6, the molecule of the photocrosslinker includes two benzophenone groups. Under the irradiation of UV light, the benzophenone group undergoes a cross-linking reaction with the ligand molecule, thereby cross-linking the quantum dots together.

[0071] It should be understood that in the photochemical reaction process shown in Figures 4 and 5, the diazonaphthoquinone group contained in the photocrosslinker can be replaced by the benzophenone group shown in Figure 6. The benzophenone group can also undergo cross-linking reaction with the molecules of the initial ligand and the polarized ligand, thereby cross-linking the quantum dots together.

[0072] Continuing to refer to Figure 3, in step 130, a non-polar developer is used to remove the portion of the film layer that is not irradiated by the ultraviolet light to form a patterned quantum dot layer. After the photochemical reaction shown in Figure 4 or Figure 5, the initial ligand coordinated with the quantum dots is polarized, and the quantum dots are cross-linked, so that the film layer becomes more stable, so that a strong (for example, a higher concentration or a stronger developing ability) non-polar developer can be used for development (i.e., removing the portion of the film layer that is not irradiated by UV light). It should be understood that any suitable non-polar developer known in the relevant art can be applied to the technical solutions taught in the present disclosure. As a non-limiting example, the non-polar developer can be a sodium hydroxide developer or a potassium hydroxide developer. The use of a non-polar developer of appropriate concentration can effectively remove the residual quantum dots in the non-exposed area, and at the same time, the film layer in the exposed area remains stable.

[0073] Referring to Figure 7 , which schematically illustrates a development process in the quantum dot layer patterning method shown in Figure 3 according to an exemplary embodiment of the present disclosure, this development process is a step-by-step development process. Specifically, as shown in Figure 7 , after the film layer including quantum dots is irradiated with UV light, the film layer can be first developed using a non-polar developer with a lower concentration to remove the portions of the film layer not exposed to the UV light. The film layer can then be developed a second time using a non-polar developer with a higher concentration to remove the remaining quantum dots. Using a step-by-step development process can more thoroughly remove the remaining quantum dots in the unexposed portions of the quantum dot layer. It should be noted that during the development stage, the thickness of the resulting quantum dot layer can be adjusted by adjusting the developer concentration and development time. Experience has shown that a film thickness of approximately 15-30 nm is optimal for the quantum dot layer. Therefore, as a non-limiting example, the concentration of the non-polar developer can be set between 0.75% and 0.85%, and the development time can be controlled to 1-2 minutes.

[0074] As mentioned above, the substrate layer can be implemented as a ZnO film layer, which can be used as an electron transport layer. Therefore, the quantum dot layer patterning method 100 shown in Figure 3 can also include the step of forming a substrate layer. In an exemplary embodiment of the present disclosure, the quantum dot layer patterning method 100 also includes: spin coating a ZnO layer on the substrate to form the substrate layer, wherein the ZnO layer is prepared by a sol-gel method (hereinafter referred to as the SG ZnO substrate layer). As a non-limiting example, the substrate can be a TFT backplane. In another exemplary embodiment of the present disclosure, the quantum dot layer patterning method 100 also includes: sputtering a ZnO layer on the substrate to form the substrate layer (hereinafter referred to as the sputtered ZnO substrate layer). There are differences in the density of the material in the SG ZnO substrate layer and the sputtered ZnO substrate layer and the surface roughness of the film layer (the material of the sputtered ZnO substrate layer is denser and the surface of the film layer is smoother), which has different effects on the development operation and will affect the quality of the resulting patterned quantum dot layer (which will be described in detail below). In addition, the SG ZnO substrate layer also contains a certain amount of organic components, but the content of the organic components is smaller than that of the quantum dot layer, while the sputtered ZnO substrate layer does not contain any organic components.

[0075] Referring to FIG8 , which schematically illustrates the development effect when the substrate layer is an SG ZnO substrate layer according to an exemplary embodiment of the present disclosure, FIG8 (a) is a fluorescence microscopy image of the quantum dot layer obtained after developing the film layer including quantum dots on the SG ZnO substrate layer using a non-polar developer with a concentration of 1%, and FIG8 (b) is a fluorescence microscopy image of the quantum dot layer obtained after developing the film layer including quantum dots on the SG ZnO substrate layer using a non-polar developer with a concentration of 0.75%. As shown in FIG8 , when developing with a non-polar developer with a concentration of 0.75%, the pattern of the quantum dot layer is relatively complete, but there is significant residue. However, when developing with a non-polar developer with a concentration of 1%, the pattern of the quantum dot layer is partially destroyed. Therefore, for the SG ZnO substrate layer, if the developer concentration is too high, the quantum dots in the exposed area of ​​the film layer may also be washed away by the developer, resulting in incomplete or peeling of the quantum dot pattern, and may even damage part of the SG ZnO substrate layer.

[0076] Referring to FIG9 , which schematically illustrates the development effect when the substrate layer is a sputtered ZnO substrate layer according to an exemplary embodiment of the present disclosure, FIG(a) is a fluorescence microscope effect image of the quantum dot layer obtained after developing the film layer including quantum dots on the sputtered ZnO substrate layer using a non-polar developer having a concentration of 1%, and FIG(b) is a fluorescence microscope effect image of the quantum dot layer obtained after developing the film layer including quantum dots on the sputtered ZnO substrate layer using a non-polar developer having a concentration of 0.75%. As shown in FIG9 , when the substrate layer is produced by sputtering ZnO, regardless of whether a non-polar developer having a concentration of 0.75% or 1% is used to develop the film layer including quantum dots, the pattern in the exposed area of ​​the film layer remains relatively intact and no obvious residue is left. This is because the sputtered ZnO substrate is denser and has a smoother surface. Therefore, when the quantum dot mixture solution is spin-coated to form a film containing quantum dots, the film's adhesion to the sputtered ZnO substrate is weaker than when the substrate is SG ZnO, making removal of residual quantum dots relatively easier. In comparison, the SG ZnO substrate is less dense and has a rougher surface. Therefore, the adhesion of the film containing quantum dots to the SG ZnO substrate is stronger, making removal of residual quantum dots relatively difficult. Therefore, under the same exposure and development conditions, residual quantum dots in the unexposed portions of the film on the sputtered ZnO substrate are more easily removed by development than those in the unexposed portions of the film on the SG ZnO substrate. Furthermore, the SG ZnO substrate formed by spin coating has relatively more defects and a rougher surface, making it susceptible to damage by highly concentrated non-polar developers, leading to partial delamination of the quantum dot layer. However, the denser structure and smoother surface of the sputtered ZnO substrate make it less susceptible to damage by non-polar developers, making delamination less likely in the exposed areas of the film.

[0077] In addition, the problem of peeling in the exposed area of ​​the film layer can be overcome by improving the crosslinking degree of the quantum dots. Referring to Figure 10, a method for improving the molecules of the photocrosslinker is schematically shown. As shown in Figure 10, the crosslinking group is a diazonaphthoquinone group. By increasing the number of diazonaphthoquinone groups in the molecules of the photocrosslinker (for example, it can be increased to 4 or 6 as shown), the reaction sites in the molecules of the photocrosslinker are increased. As a result, the crosslinking degree of the quantum dots can be increased, thereby improving the stability of the quantum dot layer in the exposed area and reducing the occurrence of film peeling in the exposed area.

[0078] Referring to Figure 11, and in combination with Figure 10, an exemplary synthesis route of a photocrosslinker according to an exemplary embodiment of the present disclosure is schematically shown. The photocrosslinker shown in Figure 11 is a trisubstituted diazonaphthoquinone derivative, and its chemical formula is shown in the previous Chemical Formula 4. As shown in Figure 11, triphenol A (whose chemical formula is shown in the following Chemical Formula 5) and 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride (whose chemical formula is shown in the following Chemical Formula 6) can be used to synthesize a trisubstituted diazonaphthoquinone derivative. Specifically, there are three hydroxyl groups in the molecule of triphenol A, and each hydroxyl group can react with 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride to replace the hydrogen in the hydroxyl group with a diazonaphthoquinone group, thereby obtaining a trisubstituted diazonaphthoquinone derivative.

[0079] It should be understood that the above-mentioned trisubstituted diazonaphthoquinone derivative photocrosslinker is merely exemplary and not restrictive. According to actual needs, compounds containing fewer or more hydroxyl groups in the molecule can be used to synthesize compounds containing fewer or more diazonaphthoquinone groups in the molecule. As a non-limiting example, 2,3,4,4-tetrahydroxybenzophenone 1,2-diazonaphthoquinone-5-sulfonate (whose chemical formula is shown in the following Chemical Formula 7) is a photocrosslinker whose molecule includes four diazonaphthoquinone groups.

[0080] Wherein, R is a diazonaphthoquinone group.

[0081] Regarding the improvements to the photocrosslinker molecules including diazonaphthoquinone groups shown in Figures 10 and 11, it is important to note that the molecules must contain solubilizing groups such as ester bonds to improve their solubility in common solvents and compatibility with quantum dot solvents. Furthermore, it should be understood that benzophenone groups can also be used, as shown in Figure 10, to increase the number of crosslinking groups in the photocrosslinker molecules, thereby increasing the number of reactive sites in the photocrosslinker molecules and thereby increasing the degree of crosslinking of the quantum dots.

[0082] As can be seen from the above description, using the quantum dot layer patterning method taught by the present disclosure, when undergoing the photochemical reaction process shown in Figure 4, the resulting patterned quantum dot layer can include at least two sub-pixel areas, wherein each sub-pixel area includes: a sub-pixel quantum dot; an initial ligand coordinated with the sub-pixel quantum dot; a polarized ligand coordinated with the sub-pixel quantum dot, the polarized ligand being generated by the reaction of the initial ligand with the acid generated by the photoacid generator, so that the molecules of the initial ligand are polarized into polar molecules; wherein at least two sub-pixel quantum dots are cross-linked together by the reaction between the initial ligand and the cross-linking group of the photocrosslinker. When undergoing the photochemical reaction process shown in Figure 5, the resulting patterned quantum dot layer may also include: at least two sub-pixel quantum dots are also cross-linked together by the reaction between the polarized ligand and the cross-linking group of the photocrosslinker. In some exemplary embodiments, the resulting quantum dot layer may also include a photoacid generator, a photocrosslinker, and a product obtained by the cross-linking reaction between the photoacid generator and the photocrosslinker. In some exemplary embodiments, the sub-pixel quantum dots included in each sub-pixel region have different quantum dot compositions. The quantum dot compositions may include any one or more of the currently available quantum dot compositions described above. Furthermore, in some exemplary embodiments, the sub-pixel quantum dots included in each sub-pixel region have different quantum dot sizes.

[0083] In the obtained patterned quantum dot layer, the component of the initial ligand can be 2-mercaptoethyl BOC amine, the acid response group can be a t-BOC group, and the cross-linking group can be a diazonaphthoquinone group or a benzophenone group; or, the chemical formula of the initial ligand molecule can be R1-acetal-R2, wherein R1 is one of a thiol group, a carboxyl group, and an amino group, R2 is an alkyl group or an aromatic group, the acid response group can be an acetal, and the cross-linking group can be a diazonaphthoquinone group or a benzophenone group. The aromatic group can include any one or more of the following groups: phenyl, alkylphenyl, thienyl, pyrimidine, aniline, naphthalene, phenoxy, etc. In some exemplary embodiments, the component of the photocrosslinker can be a trisubstituted diazonaphthoquinone derivative. In some exemplary embodiments, the thickness of the patterned quantum dot layer is between 15nm and 30nm.

[0084] Refer to Figure 12, which schematically shows the electrospectral spectrum of the patterned quantum dot layer obtained according to the exemplary embodiment of the present disclosure. The patterned quantum dot layer targeted by Figure 12 is obtained in the following manner: first, an SG ZnO substrate layer is spin-coated on the TFT backplane as a substrate (rotation speed is 3000rpm), and then a mixed solution containing red quantum dots, photoacid generator, and photocrosslinker is spin-coated to form a film layer containing red quantum dots on the SG ZnO substrate layer, and then the red quantum dots are exposed for 30 seconds and developed with a strong developer to form red sub-pixels. Then, a film layer including blue quantum dots is made in the same way to form blue sub-pixels, and finally a hole transport layer and a metal aluminum electrode are evaporated. When the blue sub-pixel is electrochemically tested, as the voltage gradually increases (from 4V to 8V), as shown in Figure 12, no spectral peak appears in the red light band, which means that there is no residual red quantum dot in the blue sub-pixel.

[0085] Referring to Figure 13, the structure of a quantum dot electroluminescent device according to an exemplary embodiment of the present disclosure is schematically shown in the form of a block diagram. As shown in Figure 13, the quantum dot electroluminescent device 300a has an inverted device structure, which includes a substrate 310, and a cathode 320, an electron transport layer 330, a patterned quantum dot layer 340, a hole transport layer 350 and an anode 360 ​​stacked in sequence. Among them, the substrate 310, the cathode 320, the electron transport layer 330, the hole transport layer 350 and the anode 360 ​​can all be made using materials and processes known in the relevant art, which will not be repeated here. The patterned quantum dot layer 340 includes n sub-pixel areas, where n is an integer greater than or equal to 1. Therefore, the patterned quantum dot layer 340 can be a quantum dot layer made according to the method described above in the present disclosure.

[0086] See Figure 14, which schematically shows the test results of the quantum dot electroluminescent device obtained according to the exemplary embodiment of the present disclosure. Figure 14 relates to a quantum dot electroluminescent device with an inverted device structure. Specifically, the quantum dot electroluminescent device is manufactured in the following manner: ZnO is sputtered on the TFT backplane as a substrate to form a sputtered ZnO substrate layer as an electron transport layer, and a mixed solution containing red quantum dots, a photoacid generator, and a photocrosslinker is spin-coated on the sputtered ZnO substrate layer. After the red quantum dots are exposed for 30 seconds, they are developed with a strong developer to form red sub-pixels. A film layer including blue quantum dots is then manufactured in the same manner to form blue sub-pixels, and finally a hole transport layer (for example, a TFB layer) and a metal Ag electrode are evaporated. As shown in Figure 14, Figure (a) is the electrospectral spectrum obtained when the blue sub-pixel in the quantum dot electroluminescent device is electrochemically tested. It can be seen that as the voltage gradually increases (from 4V to 8V), no spectral peak appears in the red light band, which means that there is no residual red quantum dot in the blue sub-pixel; Figure (b) is a fluorescence microscope effect diagram of the quantum dot layer, in which it can be seen that the pattern of the quantum dot layer is complete and there is no problem of incompleteness or peeling; the two curves in Figure (c) show the results of electrochemical testing of two quantum dot electroluminescent devices Q1 and Q2 made under the same conditions (that is, made of the same materials in the above method). As can be seen from each curve, as the voltage gradually increases (as shown in the figure, from 4V to 8V), the current density of the light-emitting devices Q1 and Q2 increases, which means that their luminous brightness also increases accordingly; the two curves in Figure (d) show the external quantum efficiency (i.e. EQE) of two quantum dot electroluminescent devices Q1 and Q2 made under the same conditions (i.e., made with the same materials in the above manner). It can be seen from each curve that when the voltage gradually increases from 4V to 8V, the EQE of the light-emitting devices Q1 and Q2 generally shows a corresponding increasing trend, and when the voltage is 8V, the EQE of the light-emitting devices Q1 and Q2 is about 0.2.

[0087] Referring to FIG15 , a block diagram schematically illustrates the structure of another quantum dot electroluminescent device according to an exemplary embodiment of the present disclosure. As shown in FIG15 , the quantum dot electroluminescent device 300b has an upright device structure, comprising a substrate 310, and an anode 360, a hole transport layer 350, a quantum dot layer 340, an electron transport layer 330, and a cathode 320 stacked in sequence. The substrate 310, cathode 320, electron transport layer 330, hole transport layer 350, and anode 360 ​​are identical to their counterparts shown in FIG13 , and can all be fabricated using materials and processes known in the art, which will not be further described herein.

[0088] As non-limiting examples, the quantum dot electroluminescent devices shown in Figures 13 and 15 can be quantum dot light-emitting diodes or quantum dot displays. Furthermore, it should be understood that the quantum dot electroluminescent devices provided according to exemplary embodiments of the present disclosure can also include other functional film layers well known to those skilled in the art. These functional film layers will not be described in detail here.

[0089] Referring to FIG16 , a block diagram schematically illustrates the structure of a display device according to an exemplary embodiment of the present disclosure. As shown in FIG16 , a display device 500 includes a quantum dot electroluminescent device 510. The quantum dot electroluminescent device 510 can be implemented as the aforementioned quantum dot electroluminescent device 300a or the quantum dot electroluminescent device 300b. Referring to FIG17 , a block diagram schematically illustrates the structure of another display device according to an exemplary embodiment of the present disclosure. As shown in FIG17 , a display device 500 includes a quantum dot electroluminescent device 510, and the quantum dot electroluminescent device 510 includes n sub-pixels, where n is an integer greater than 1. Therefore, the quantum dot electroluminescent device 510 can also be implemented as the aforementioned quantum dot electroluminescent device 300a or the quantum dot electroluminescent device 300b, where the quantum dot electroluminescent device 300a or the quantum dot electroluminescent device 300b includes at least two sub-pixel regions. In specific implementations, the display device provided according to the exemplary embodiments of the present disclosure can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, or a navigation system. It should be understood that the other essential components of the display device are known to those skilled in the art and are not described in detail here, nor should they be construed as limiting the present disclosure.

[0090] The terms used in this disclosure are only used to describe the embodiments in this disclosure and are not intended to limit this disclosure. As used in this disclosure, the singular forms "a", "an" and "the" are intended to also include the plural forms, unless the context clearly indicates otherwise. It is also to be understood that the terms "include" and "comprise" when used in this disclosure refer to the presence of the features mentioned, but do not exclude the presence of one or more other features or the addition of one or more other features. As used in this disclosure, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be understood that although the terms "first", "second", "third" etc. can be used to describe various features in this disclosure, these features should not be limited by these terms. These terms are only used to distinguish one feature from another.

[0091] Unless otherwise defined, all terms (including technical and scientific terms) used in this disclosure have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. It is also 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 in this disclosure.

[0092] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction and without violating technical principles, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, or may omit some technical features from the different embodiments or examples described in this specification, and the embodiments or examples obtained based on such combination, combination or omission are also considered to fall within the scope of the present disclosure.

[0093] The method described in the present disclosure includes one or more steps or actions. These method steps and / or actions do not have to be performed in the order described in the present disclosure, but can be performed in a different order, for example, they can be performed simultaneously or in a reverse order, as long as they do not conflict with the principles of the technical solutions described in the present disclosure. In addition, according to actual needs, the steps or actions in the method described in the present disclosure can be replaced with different steps or actions, or can also include additional steps or actions.

[0094] Although the present disclosure has been described in detail in conjunction with certain exemplary embodiments, it is not to be limited to the specific forms described in this disclosure. Rather, the scope of the present disclosure is limited only by the appended claims.

Claims

1. A method for patterning a quantum dot layer, comprising: Forming a film layer including quantum dots, initial ligands coordinated with the quantum dots, a photoacid generator and a photocrosslinker on the substrate layer, wherein the molecules of the initial ligands include an acid-responsive group capable of reacting with an acid, and the molecules of the photocrosslinker include at least two crosslinking groups capable of undergoing a crosslinking reaction with the initial ligands; Irradiating the quantum dot retention region in the film layer with ultraviolet light, so that in the quantum dot retention region, the initial ligand reacts with the acid generated by the photoacid generator, so that the molecules of the initial ligand are polarized into polar molecules, thereby generating polarized ligands, and the initial ligand reacts with the cross-linking group; A non-polar developer is used to remove the portion of the film layer that is not irradiated by the ultraviolet light to form a patterned quantum dot layer.

2. The method for patterning a quantum dot layer according to claim 1, wherein: During the period when the ultraviolet light irradiates the quantum dot retention region, the polarized ligand reacts with the cross-linking group in the quantum dot retention region.

3. The method for patterning a quantum dot layer according to claim 1, wherein: During the period when the ultraviolet light irradiates the quantum dot retention region, the photoacid generator reacts with the crosslinking group of the photocrosslinking agent in the quantum dot retention region.

4. The method for patterning a quantum dot layer according to claim 1, wherein: The component of the initial ligand is 2-mercaptoethyl BOC amine, and the acid response group is a t-BOC group; The crosslinking group is a diazonaphthoquinone group or a benzophenone group.

5. The method for patterning a quantum dot layer according to claim 1, wherein: The chemical formula of the initial ligand is R1-acetal-R2, wherein R1 is one of a thiol group, a carboxyl group, and an amino group, R2 is an alkyl group or an aromatic group, and the acid-responsive group is an acetal; The crosslinking group is a diazonaphthoquinone group or a benzophenone group.

6. The method for patterning a quantum dot layer according to claim 4 or 5, wherein: In the case where the crosslinking group is a diazonaphthoquinone group, the component of the photocrosslinking agent is a tri-substituted diazonaphthoquinone derivative.

7. The method for patterning a quantum dot layer according to claim 1, wherein: The mass of the photoacid generator is within 20% of the mass of the quantum dots, and the mass of the photocrosslinker is within 20% of the mass of the quantum dots.

8. The method for patterning a quantum dot layer according to claim 1, further comprising: providing a substrate; A zinc oxide layer is spin-coated on the substrate to form the base layer, wherein the zinc oxide layer is prepared by a sol-gel method.

9. The method for patterning a quantum dot layer according to claim 1, further comprising: providing a substrate; A zinc oxide layer is sputtered on the substrate to form the underlayer.

10. The method for patterning a quantum dot layer according to claim 1, wherein: The step of irradiating the quantum dot retention region in the film layer with ultraviolet light comprises: irradiating a mask that shields the film layer with the ultraviolet light, wherein the mask comprises a light-transmitting region and a light-shielding region, and the light-transmitting region corresponds to the quantum dot retention region.

11. The method for patterning a quantum dot layer according to claim 1, wherein: The step of removing the portion of the film layer that is not irradiated by the ultraviolet light by using a non-polar developer comprises: Using a first non-polar developer having a first concentration to perform a first development on the film layer; and After the first development, the film layer is developed for a second time using a second non-polar developer having a second concentration, wherein the second concentration is greater than the first concentration.

12. A patterned quantum dot layer comprising at least one sub-pixel region, wherein: Each sub-pixel area includes: Sub-pixel quantum dots; an initial ligand coordinated with the sub-pixel quantum dot; A polarized ligand coordinated with the sub-pixel quantum dot, wherein the polarized ligand is generated by the reaction between the initial ligand and the acid generated by the photoacid generator, so that the molecules of the initial ligand are polarized into polar molecules; Wherein, at least two sub-pixel quantum dots are cross-linked together through the reaction between the initial ligand and the cross-linking group of the photo-cross-linking agent.

13. The patterned quantum dot layer according to claim 12, wherein: At least two sub-pixel quantum dots are also cross-linked together through the reaction between the polarized ligand and the cross-linking group of the photo-cross-linking agent.

14. The patterned quantum dot layer according to claim 12, wherein: Each of the sub-pixel regions further includes: the photoacid generator, the photocrosslinking agent, and a product obtained by a reaction between the photoacid generator and the photocrosslinking agent.

15. The patterned quantum dot layer of claim 12, wherein: The component of the initial ligand is 2-mercaptoethyl BOC amine; The polarized ligand is 2-aminoethanethiol; The crosslinking group is a diazonaphthoquinone group or a benzophenone group.

16. The patterned quantum dot layer of claim 12, wherein: The chemical formula of the initial ligand is Wherein, R1 is one of thiol, carboxyl and amino, and R2 is an alkyl or aromatic group; The chemical formula of the polar ligand is The crosslinking group is a diazonaphthoquinone group or a benzophenone group.

17. The patterned quantum dot layer according to claim 15 or 16, wherein: In the case where the crosslinking group is a diazonaphthoquinone group, the component of the photocrosslinking agent is a tri-substituted diazonaphthoquinone derivative.

18. The patterned quantum dot layer according to claim 12, wherein: The thickness of the patterned quantum dot layer is between 15 nm and 30 nm.

19. The patterned quantum dot layer of claim 12, wherein: The patterned quantum dot layer includes at least two sub-pixel regions, each sub-pixel region is configured to emit light of different colors, and each sub-pixel region includes sub-pixel quantum dots with different quantum dot components.

20. The patterned quantum dot layer of claim 12, wherein: The patterned quantum dot layer includes at least two sub-pixel regions, each sub-pixel region is configured to emit light of different colors, and each sub-pixel region includes sub-pixel quantum dots with different quantum dot sizes.

21. A quantum dot electroluminescent device, comprising: A cathode, an electron transport layer, a patterned quantum dot layer according to any one of claims 12 to 20, a hole transport layer and an anode are sequentially stacked on a substrate; or An anode, a hole transport layer, a patterned quantum dot layer according to any one of claims 12 to 20, an electron transport layer and a cathode are sequentially stacked on a substrate.

22. The quantum dot electroluminescent device according to claim 19, wherein: The electron transport layer is a zinc oxide layer.

23. The quantum dot electroluminescent device according to claim 22, wherein: The content of organic components in the zinc oxide layer is greater than 0 and less than the content of organic components in the patterned quantum dot layer.

24. The quantum dot electroluminescent device according to claim 22, wherein: The content of organic components in the zinc oxide layer is 0.

25. A display device comprising the quantum dot electroluminescent device according to any one of claims 21 to 24.

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