Perovskite quantum dot patterning method based on concave template filling

Abstract

The invention discloses a perovskite quantum dot patterning method based on concave template filling, and belongs to the technical field of full-color display. The method comprises the following steps: preparing a first patterned PDMS concave template on the basis of a first convex template; filling a pit of the first patterned PDMS concave template with the first perovskite quantum dot slurry, and heating and curing the first perovskite quantum dot slurry to form a first perovskite quantum dot polymer film; spin-coating first auxiliary slurry on the surface of the patterned PDMS concave template with the first perovskite quantum dot polymer film, and heating and curing to form a first auxiliary film; stripping a first perovskite quantum dot polymer film and a first auxiliary film from the patterned PDMS concave template; and transferring the first perovskite quantum dot polymer film to a target substrate, and removing the first auxiliary film. According to the method, the perovskite quantum dot light conversion film with high resolution and micron-sized thickness can be prepared, and high-efficiency blue light conversion is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of full-color display, and in particular to a perovskite quantum dot patterning method based on concave template filling. Background Art

[0002] The current methods for quantum dot patterning mainly include:

[0003] Photolithography technology: Quantum dots or photoresist are patterned through UV exposure, development and other steps, but UV exposure and development may cause surface defects of quantum dots and reduce luminescence efficiency; in addition, this method requires complex ligand exchange or cross-linking treatment, which affects the charge injection performance.

[0004] Inkjet printing technology: Quantum dot ink is directly sprayed onto the substrate to form a pattern. This method has a low resolution (usually <500PPI) and is easily affected by the "coffee ring effect", resulting in uneven edges. In addition, this method is difficult to control ink diffusion.

[0005] Electrophoretic deposition (EPD) and dielectrophoretic deposition: Use electric fields to drive charged quantum dots to deposit on electrodes. This method has high equipment costs and requires precise control of electric field parameters; in addition, the method has limited solvent selection, which may affect the stability of quantum dots.

[0006] Laser etching technology: laser irradiation is used to cause the ligands on the surface of quantum dots to fall off or cross-link, forming an insulating barrier to isolate pixels. This method relies on specific photocurable glue or ligand design, and has a limited range of applicable materials; in addition, the laser energy of this method needs to be strictly controlled to avoid excessive damage.

[0007] Transfer technology: The quantum dot pattern is transferred to the target substrate through an elastic stamp or nanoimprinting. This method requires high alignment accuracy and is prone to pattern offset or loss; in addition, the transfer quality of this method is unstable, affecting the reliability of the device.

[0008] Nanoimprinting: Using molds to imprint patterns, but mold preparation is complex.

[0009] Thermal lithography: patterning is induced by thermal effects, and the equipment cost is high.

[0010] Therefore, the development of patterned integration technology suitable for perovskite quantum dot materials is of great significance for promoting the practical application of this material and the development of various new display technologies.

[0011] In view of this, the present invention is proposed. Summary of the invention

[0012] The object of the present invention is to provide a perovskite quantum dot patterning method based on concave template filling to solve or improve the above technical problems.

[0013] The present invention can be implemented like this:

[0014] In a first aspect, the present invention provides a method for patterning perovskite quantum dots based on concave template filling, comprising the following steps:

[0015] Based on the first convex template, a first patterned PDMS concave template is prepared;

[0016] Filling the first perovskite quantum dot slurry into the pits of the first patterned PDMS concave template, heating and curing, so as to form a first perovskite quantum dot polymer film in the pits of the first patterned PDMS concave template;

[0017] Spin coating a first auxiliary slurry on the surface of a first patterned PDMS concave template having a first perovskite quantum dot polymer film, and heat curing the first auxiliary slurry to form a first auxiliary film;

[0018] The first perovskite quantum dot polymer film and the first auxiliary film are peeled off from the first patterned PDMS concave template to obtain a first composite film containing both the first perovskite quantum dot polymer film and the first auxiliary film; the first perovskite quantum dot polymer film in the first composite film is transferred to a target substrate, and then the first auxiliary film is removed.

[0019] In an optional embodiment, the first convex template is a SU8 convex template prepared by photolithography.

[0020] In an optional embodiment, the first patterned PDMS concave template is obtained by pouring and curing PDMS on the first convex template.

[0021] In an optional embodiment, the first perovskite quantum dot slurry includes a first perovskite quantum dot reaction precursor powder, a first organic polymer and a first solvent;

[0022] Wherein, the first solvent includes at least one of DMF and DMSO.

[0023] In an optional embodiment, the first auxiliary slurry includes a second organic polymer and a second solvent, and the second solvent is neither soluble nor destructive to the perovskite quantum dot polymer film;

[0024] In an optional embodiment, the first auxiliary film is removed by dissolving with a solvent.

[0025] In an optional embodiment, the method further includes: transferring a second composite film comprising a second perovskite quantum dot polymer film and a second auxiliary film to pits existing on the surface of the same target substrate, and then removing the second auxiliary film.

[0026] In an optional embodiment, the preparation of the second composite film includes:

[0027] Based on the second convex template, a second patterned PDMS concave template is prepared;

[0028] Filling the second perovskite quantum dot slurry into the pits of the second patterned PDMS concave template, and heating and curing to form a second perovskite quantum dot polymer film in the pits of the second patterned PDMS concave template;

[0029] Spin coating a second auxiliary slurry on the surface of the second patterned PDMS concave template having a second perovskite quantum dot polymer film, and heat curing the second auxiliary slurry to form a second auxiliary film;

[0030] The second perovskite quantum dot polymer film and the second auxiliary film are peeled off from the second patterned PDMS concave template to obtain a second composite film containing both the second perovskite quantum dot polymer film and the second auxiliary film.

[0031] In an optional embodiment, the filling depth of the first perovskite quantum dot slurry is less than or equal to the pit depth of the first patterned PDMS concave template; and / or, the filling depth of the second perovskite quantum dot slurry is less than or equal to the pit depth of the second patterned PDMS concave template.

[0032] In an optional embodiment, the quantum dots in the first perovskite quantum dot polymer film and the second perovskite quantum dot polymer film have different colors.

[0033] The beneficial effects of the present invention include:

[0034] The perovskite quantum dot patterning method based on concave template filling provided by the present invention forms a first perovskite quantum dot polymer film in the pit of the first patterned PDMS concave template; then combines the first perovskite quantum dot polymer film with a first auxiliary film to form a first composite film; after the first composite film is peeled off from the template, it is transferred to the target substrate, and then the first auxiliary film is removed. The method has strong applicability, does not cause significant damage to the optical properties of the quantum dot material, can realize the preparation of high-thickness and high-resolution quantum dot light conversion color films, and can realize high-efficiency blue light conversion, thereby effectively solving the technical barriers existing in existing OLED or mini / micro-LED display technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 It is a structural schematic diagram of the first convex template in the present invention;

[0037] Figure 2 Schematic diagram of the structure of the first patterned PDMS concave template in the present invention;

[0038] Figure 3 Schematic diagram of forming a first perovskite quantum dot polymer film in the pits of the first patterned PDMS concave template in the present invention;

[0039] Figure 4 It is a schematic diagram of forming a first composite film in a concave pit of a first patterned PDMS concave template in the present invention;

[0040] Figure 5 is a schematic diagram of transferring the first composite film to the target substrate in the present invention;

[0041] Figure 6 It is a schematic diagram of removing the first auxiliary film after the first composite film is transferred to the target substrate in the present invention;

[0042] Figure 7 is a schematic diagram of transferring the second composite film to the same target substrate in the present invention;

[0043] Figure 8 It is a schematic diagram of removing the second auxiliary film after the second composite film is transferred to the target substrate in the present invention.

[0044] Icons: 11-first convex template; 12-first patterned PDMS concave template; 13-first perovskite quantum dot polymer film; 14-first auxiliary film; 15-first composite film; 16-target substrate; 17-second perovskite quantum dot polymer film; 18-second auxiliary film; 19-second composite film. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0046] The perovskite quantum dot patterning method based on concave template filling provided by the present invention is specifically described below.

[0047] The present invention provides a perovskite quantum dot patterning method based on concave template filling, comprising the following steps:

[0048] Step S10: Based on the first convex template 11, a first patterned PDMS concave template 12 is prepared.

[0049] The first convex plate 11 may be a SU8 convex plate (such as Figure 1 The template prepared by this method has high resolution, thickness, verticality and uniformity.

[0050] The above-mentioned "SU8 convex template" uses SU-8 photoresist as the main material and utilizes photolithography technology to produce a template with a convex structure.

[0051] SU-8 is a negative photoresist with good chemical stability, mechanical properties and optical properties. It undergoes a cross-linking reaction under ultraviolet light, and the unexposed part can be dissolved in the developer to form a specific pattern.

[0052] The preparation of SU8 convex template can be referred to as follows: first, evenly spin-coat a layer of SU-8 photoresist on a substrate (such as a silicon wafer, etc.), then align the designed mask with a convex pattern with the substrate coated with photoresist, and perform photolithography by ultraviolet light irradiation. During the photolithography process, the photoresist corresponding to the transparent part of the mask undergoes a cross-linking reaction, while the photoresist of the masked part remains intact. After the development step, the uncross-linked photoresist is removed, leaving a SU-8 convex structure corresponding to the convex pattern of the mask on the substrate, that is, the SU8 convex template.

[0053] In some optional embodiments, the first patterned PDMS recessed template 12 (eg Figure 2 As shown in the figure, the first convex template 11 is obtained by pouring PDMS and curing it.

[0054] Exemplarily, PDMS casting and curing may be pouring a liquid substance obtained by mixing a polydimethylsiloxane (PDMS) prepolymer with a curing agent into a preset mold, and curing the mixture in the mold to obtain a PDMS product with a preset specific shape and structure.

[0055] The first patterned PDMS recessed template 12 has a relatively low surface energy, which is beneficial to the subsequent selective filling of the quantum dot precursor polymer solution and the peeling of the cured quantum dot polymer film.

[0056] Step S20: Fill the first perovskite quantum dot slurry into the pits of the first patterned PDMS concave template 12, heat and cure, so as to form a first perovskite quantum dot polymer film 13 (such as Figure 3 shown).

[0057] In some optional embodiments, the first perovskite quantum dot slurry includes a first perovskite quantum dot reaction precursor powder, a first organic polymer and a first solvent.

[0058] The first solvent may illustratively but not limitatively include at least one of DMF and DMSO.

[0059] The first perovskite quantum dot reaction precursor powder and the first organic polymer may both be made of commonly used related materials in the art, and no further limitations are given herein.

[0060] The viscosity of the first perovskite quantum dot slurry is easy to adjust, which facilitates the subsequent selective filling and in-situ generation of a perovskite quantum dot polymer film.

[0061] The filling depth of the first perovskite quantum dot slurry is less than or equal to the pit depth of the first patterned PDMS recessed template 12 .

[0062] In specific operation, the first perovskite quantum dot slurry may be dripped onto the surface of the first patterned PDMS recessed template 12, and then the first perovskite quantum dot slurry is filled into the pits of the first patterned PDMS recessed template 12 by a doctor blade process, so that no residue is left on the upper surface of the first patterned PDMS recessed template 12. By heating and curing, the in-situ synthesis of the perovskite quantum dots is achieved, and the perovskite quantum dots have better dispersion and uniformity in the polymer matrix.

[0063] Step S30: Spin-coat the first auxiliary slurry on the surface of the first patterned PDMS concave template 12 having the first perovskite quantum dot polymer film 13, and heat and cure the first auxiliary slurry to form a first auxiliary film 14 (such as Figure 4 shown).

[0064] In some optional embodiments, the first auxiliary slurry may include a second organic polymer and a second solvent, and the second solvent is neither soluble nor destructive to the perovskite quantum dot polymer film, so as to facilitate subsequent peeling and separation of the film.

[0065] The second solvent may be toluene, for example. The second organic polymer may be any commonly used material in the art, and no further limitation is given herein.

[0066] Step S40: peel off the first perovskite quantum dot polymer film 13 and the first auxiliary film 14 from the first patterned PDMS concave template 12 to obtain a first composite film 15 containing both the first perovskite quantum dot polymer film 13 and the first auxiliary film 14; transfer the first perovskite quantum dot polymer film 13 in the first composite film 15 to a target substrate 16 (such as Figure 5 ), and then remove the first auxiliary film 14 (as shown Figure 6 shown).

[0067] In some optional embodiments, the first auxiliary film 14 is removed by dissolving with a solvent. The solvent for dissolving the first auxiliary film 14 may be the second solvent mentioned above.

[0068] Furthermore, after step S40, step S50 may be included: transferring the second composite film 19 containing the second perovskite quantum dot polymer film 17 and the second auxiliary film 18 to the pits existing on the surface of the same target substrate 16 (such as Figure 7 ), and then remove the second auxiliary film 18 (as shown Figure 8 shown).

[0069] The above-mentioned “same target substrate 16” is the target substrate 16 to which the first perovskite quantum dot polymer film 13 is transferred in step S40. The specific transfer position of the second composite film 19 is the gap between the first perovskite quantum dot polymer film 13 on the surface of the target substrate 16, and more specifically, the second perovskite quantum dot polymer film 17 in the second composite film 19 is transferred to the gap between the first perovskite quantum dot polymer film 13 on the surface of the target substrate 16.

[0070] Similarly, the preparation of the second composite film 19 may include:

[0071] Based on the second convex template, a second patterned PDMS concave template is prepared;

[0072] Filling the second perovskite quantum dot slurry into the pits of the second patterned PDMS concave template, heating and curing, so as to form a second perovskite quantum dot polymer film 17 in the pits of the second patterned PDMS concave template;

[0073] Spin coating the second auxiliary slurry on the surface of the second patterned PDMS concave template having the second perovskite quantum dot polymer film 17, and heat curing the second auxiliary slurry to form a second auxiliary film 18;

[0074] The second perovskite quantum dot polymer film 17 and the second auxiliary film 18 are peeled off from the second patterned PDMS recessed template to obtain a second composite film 19 containing both the second perovskite quantum dot polymer film 17 and the second auxiliary film 18 .

[0075] Wherein, the filling depth of the second perovskite quantum dot slurry is less than or equal to the pit depth of the second patterned PDMS concave template.

[0076] The slurry for forming the second perovskite quantum dot polymer film 17 can be prepared by referring to the prior art, and no further limitation is given here.

[0077] The quantum dots in the first perovskite quantum dot polymer film 13 and the second perovskite quantum dot polymer film 17 have different colors, such as red quantum dots or green quantum dots, respectively, and can be combined with blue light OLED or mini / micro-LED to achieve full-color display.

[0078] In summary, the perovskite quantum dot patterning method based on concave template filling provided by the present invention has strong applicability, will not cause significant damage to the optical properties of the quantum dot material, can realize the preparation of high-thickness and high-resolution quantum dot light conversion color films, and can achieve high-efficiency blue light conversion, thereby effectively solving the technical barriers existing in existing OLED or mini / micro-LED display technologies.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for patterning perovskite quantum dots based on concave template filling, characterized in that: The following steps are involved: Based on the first convex template, a first patterned PDMS concave template is prepared; Filling the first perovskite quantum dot slurry into the pits of the first patterned PDMS concave template, heating and curing, so as to form a first perovskite quantum dot polymer film in the pits of the first patterned PDMS concave template; Spin coating a first auxiliary slurry on the surface of the first patterned PDMS concave template having the first perovskite quantum dot polymer film, and heating and curing the first auxiliary slurry to form a first auxiliary film; The first perovskite quantum dot polymer film and the first auxiliary film are peeled off from the first patterned PDMS concave template to obtain a first composite film containing both the first perovskite quantum dot polymer film and the first auxiliary film; the first perovskite quantum dot polymer film in the first composite film is transferred to a target substrate, and then the first auxiliary film is removed.

2. The method for patterning perovskite quantum dots based on concave template filling according to claim 1, characterized in that: The first convex template is a SU8 convex template prepared by photolithography.

3. The method for patterning perovskite quantum dots based on concave template filling according to claim 1, characterized in that: The first patterned PDMS concave template is obtained by pouring and curing PDMS on the first convex template.

4. The method for patterning perovskite quantum dots based on concave template filling according to claim 1, characterized in that: The first perovskite quantum dot slurry includes a first perovskite quantum dot reaction precursor powder, a first organic polymer and a first solvent; Wherein, the first solvent includes at least one of DMF and DMSO.

5. The method for patterning perovskite quantum dots based on concave template filling according to claim 4, characterized in that: The first auxiliary slurry includes a second organic polymer and a second solvent, and the second solvent is neither soluble nor destructive to the perovskite quantum dot polymer film.

6. The method for patterning perovskite quantum dots based on concave template filling according to claim 1, characterized in that: The first auxiliary film is removed by dissolving with a solvent.

7. The method for patterning perovskite quantum dots based on concave template filling according to claim 1, characterized in that: Also includes: The second composite film including the second perovskite quantum dot polymer film and the second auxiliary film is transferred to the pits existing on the surface of the same target substrate, and then the second auxiliary film is removed.

8. The method for patterning perovskite quantum dots based on concave template filling according to claim 7, characterized in that: The preparation of the second composite film comprises: Based on the second convex template, a second patterned PDMS concave template is prepared; Filling the second perovskite quantum dot slurry into the pits of the second patterned PDMS concave template, and heating and curing to form a second perovskite quantum dot polymer film in the pits of the second patterned PDMS concave template; Spin coating a second auxiliary slurry on the surface of the second patterned PDMS concave template having a second perovskite quantum dot polymer film, and heat curing the second auxiliary slurry to form a second auxiliary film; The second perovskite quantum dot polymer film and the second auxiliary film are peeled off from the second patterned PDMS concave template to obtain a second composite film containing both the second perovskite quantum dot polymer film and the second auxiliary film.

9. The method for patterning perovskite quantum dots based on concave template filling according to claim 8, characterized in that: The filling depth of the first perovskite quantum dot slurry is less than or equal to the pit depth of the first patterned PDMS concave template; and / or the filling depth of the second perovskite quantum dot slurry is less than or equal to the pit depth of the second patterned PDMS concave template.

10. The method for patterning perovskite quantum dots based on concave template filling according to claim 8, characterized in that: The quantum dots in the first perovskite quantum dot polymer film and the second perovskite quantum dot polymer film have different colors.

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