Perovskite patterned thin film, method of making and use thereof

Abstract

This invention provides a perovskite patterned thin film, its preparation method, and its application. The preparation method includes: coating a PbX2 precursor onto a substrate and annealing to obtain a PbX2 thin film substrate; coating an AY salt onto a patterned nanostamp and annealing to obtain an AY thin film nanostamp; and performing nanoimprinting to obtain an APb(X,Y)3 perovskite patterned thin film; wherein X and Y are independently one or more of I, Br, and Cl, and the AY salt includes amine salts and / or Cs-based salts. This invention precisely constructs perovskite patterns on a PbX2 substrate through a combination of contact imprinting and ion diffusion, obtaining a smooth surface thin film with PbX2 / perovskite / PbX2 coplanarity. The perovskite pattern serves as the active region, while the remaining PbX2 naturally acts as a wide-bandgap insulating / inert barrier material. This results in low film residue and significantly improved yield.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic materials technology, and more specifically, to a perovskite patterned thin film, its preparation method, and its application. Background Technology

[0002] Organic lead halide perovskite materials, as a new generation of organic-inorganic hybrid semiconductor materials, have attracted widespread attention in related fields and are widely used in optoelectronic devices such as photovoltaics, light emission, detection, and lasers. In particular, the certified efficiency of perovskite thin film-based solar cells has reached over 25%, comparable to commercial silicon-based solar cells. Therefore, research and exploration of perovskite materials / thin films in various optoelectronic applications are in full swing. Among them, the patterning technology of perovskite thin films has always been a hot topic in the field. Achieving high-quality perovskite patterns using simple processes will become a highly promising process technology in future semiconductor technology.

[0003] Perovskite patterning techniques are mainly divided into two categories: bottom-up growth methods and top-down etching methods. Top-down etching methods use electron beam / ion beam etching to construct patterns on pre-formed perovskite films. However, perovskite is an ionic compound semiconductor, and etching significantly reduces the quality of the perovskite pattern, making it inherently unsuitable for perovskite processing. Bottom-up growth methods can be further divided into: inkjet printing, laser direct writing, nanoimprinting, substrate pre-patterning, and stencil-assisted methods. Inkjet printing requires sophisticated equipment and results in poor perovskite patterning unit film quality and resolution; laser direct writing produces flexible patterns but the perovskite quality is poor and uncontrollable; substrate pre-patterning produces high-quality perovskite patterns with controllable growth conditions, but the pre-patterning process is complex and requires specific substrate conditions; stencil-assisted methods are typically used for perovskite patterns constructed through vapor deposition, but the perovskite material obtained through vapor deposition itself is of poor quality. Therefore, in summary, nanoimprinting can guarantee the quality of perovskite patterns and has a simple and low-cost process, making it one of the preferred methods for processing perovskite materials.

[0004] Nanoimprinting utilizes perovskite materials / films grown from solution, imprinting and confining the liquid film in its "soft" state to obtain the desired perovskite pattern. However, traditional nanoimprinting methods struggle to ensure the absence of excess residue on the substrate after imprinting. Furthermore, the removal of the nanoimprint also impacts pattern yield. Additionally, the reuse of the nanoimprint requires complex subsequent cleaning steps, hindering large-scale patterning. Most critically, traditional nanoimprinting methods cannot avoid residue issues. The imprinting process requires precise pressure control to prevent unwanted perovskite residue from growing in locations outside the intended pattern. Simultaneously, nanoimprint removal also affects pattern quality and yield. During confined growth, perovskite tends to nucleate and grow along the nanoimprint wall; therefore, nanoimprint removal can potentially affect the already formed pattern, reducing the final pattern yield, and the entire process is relatively complex. Chinese patent CN114122266A discloses a method for preparing surface-patterned organic-inorganic hybrid perovskite thin films. The method involves spin-coating a metal halide onto a substrate, then imprinting the semi-wet metal halide film using a pattern stamp, removing the stamp, annealing and crystallizing, sprinkling MAX powder, and heating to react and obtain the perovskite thin film. However, this method uses a soft-stencil imprinting technique combined with a vapor-phase assisted method, which is complex and makes it difficult to control the quality of the resulting pattern. Furthermore, the patterned structure prepared by this method is a raised structure, requiring the fabrication of an additional intermediate insulating layer for subsequent thin-film optoelectronic devices, a process that is complex and easily affects the quality of the perovskite pattern. In addition, traditional nanoimprinting methods follow the processes of early organic material patterning methods, and for perovskite materials, nanoimprinting techniques suitable for perovskite materials and utilizing their properties urgently need to be developed. Summary of the Invention

[0005] The main objective of this invention is to provide a perovskite patterned thin film, its preparation method and application, in order to solve the problems of excessive residue, low pattern yield and complex optoelectronic device fabrication when using nanoimprinting for perovskite patterning in the prior art.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a perovskite patterned thin film is provided, comprising the following steps: Step S1, coating a PbX2 precursor on a substrate and performing a first annealing to obtain a PbX2 thin film substrate; Step S2, coating an AY salt on a patterned nanoprinter and performing a second annealing to obtain an AY thin film nanoprinter; Step S3, nanoimprinting the PbX2 thin film substrate using the AY thin film nanoprinter to obtain an APb(X,Y)3 perovskite patterned thin film; wherein X and Y are independently one or more of I, Br, and Cl, and the AY salt includes amine salts and / or Cs-based salts.

[0007] Furthermore, the PbX2 precursor includes PbX2 and / or PbX2 derivatives, and the PbX2 derivatives include PbX2-DMSO and / or PbX2-NMP.

[0008] Furthermore, AY salts include one or more of MAY, FAY, and CsY.

[0009] Furthermore, the substrate material includes one or more of transparent conductive glass, oxides, and organic polymers, and the nanoprint material includes one or more of PDMS, PMMA, and Al2O3; preferably, the transparent conductive glass includes one or more of ITO, FTO, and IZO; the oxide includes one or more of Al2O3, TiO2, SnO2, and ZnO; the organic polymer material includes one or more of PMMA, PDMS, and PEIE; more preferably, the substrate material is one or more of ITO, ZnO, and PEIE.

[0010] Furthermore, in step S1, the temperature of the first annealing is 60–80°C, and the time is 0.5–2 min.

[0011] Further, in step S2, the temperature of the second annealing is 50-70°C and the time is 0.5-2 min; preferably, before coating with AY salt, a step of hydrophilic treatment is included on the surface of the patterned nanoprint; more preferably, the hydrophilic treatment is a treatment with ultraviolet light and ozone for 5-15 min.

[0012] Further, in step S3, the pressure applied for nanoimprinting is 0-100 MPa, preferably 0.5-2 MPa, and the pressure application time is 0.5-2 min; preferably, step S3 also includes a third annealing; more preferably, the temperature of the third annealing is 70-300℃, preferably 80-120℃, and the time is 3-7 min.

[0013] According to another aspect of the present invention, a perovskite patterned thin film is provided, which is obtained by the preparation method of the present invention.

[0014] According to another aspect of the present invention, the application of the above-described perovskite patterned thin film in optoelectronic devices is provided.

[0015] According to another aspect of the present invention, an optoelectronic device is provided, comprising the above-described perovskite patterned thin film; preferably, the optoelectronic device is a solar cell, Micro-LED, Mini-LED, or OLED.

[0016] Based on the unique film formation method of perovskite materials, this invention designs a unique "in-situ two-step synthesis method" patterning method for perovskite based on nanoimprinting, to realize the preparation of coplanar perovskite patterned structures.

[0017] Firstly, the preparation method of this invention fully utilizes the ion migration characteristics of organolead halide perovskite materials and the wide bandgap inertness of the precursor PbX2. Using nano-stamps as the diffusion substrate for AY salt, perovskite patterns are precisely constructed on the PbX2 substrate through a combination of contact imprinting and ion diffusion, thereby successfully forming a coplanar structure of PbX2 / perovskite / PbX2. The perovskite pattern serves as the active region, while the remaining PbX2 naturally acts as a wide bandgap insulating / inert barrier material.

[0018] Secondly, the preparation method of the present invention grows perovskite patterns in situ through a two-step synthesis method, which can fundamentally avoid the residue and peeling problems that are easy to occur in traditional nanoimprinting methods. The resulting pattern has a low residue rate and a greatly improved yield.

[0019] Thirdly, the preparation method of the present invention is simple, and the perovskite patterned thin film obtained is a coplanar smooth thin film. No subsequent planarization treatment is required for the direct fabrication of optoelectronic devices. It can be applied to a variety of optoelectronic devices such as Mini / Micro-LED, solar cells, and photodetectors, and has a wide range of applications. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 A flow chart of a perovskite patterned thin film preparation process according to an embodiment of the present invention is shown;

[0022] Figure 2 A process flow diagram for fabricating a perovskite Micro-LED device according to an embodiment of the present invention is shown; and

[0023] Figure 3 A photograph of a Micro-LED device with a perovskite patterned thin film according to Embodiment 1 of the present invention is shown.

[0024] The above figures include the following reference numerals:

[0025] 1. PbX2; 2. AY salts; 3. Perovskite APb(X,Y)3; S1, PbX2 precursor film coated; S2, AY salt film coated; S3, Nanoimprinting; A, Substrate; B, Nanoprint; C, Perovskite patterned film; D, Top transport layer; E, Driver; F, Perovskite Micro-LED; G, Driver controls light emission. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] As described in the background section of this invention, existing technologies suffer from problems such as high residue and low pattern yield when using nanoimprinting for perovskite patterning. To address these issues, in a typical embodiment of this invention, a method for preparing a patterned perovskite thin film is provided, comprising the following steps: Step S1, coating a PbX2 precursor onto a substrate and performing a first annealing to obtain a PbX2 thin film substrate; Step S2, coating an AY salt onto a patterned nanoimprint and performing a second annealing to obtain an AY thin film nanoimprint; Step S3, nanoimprinting the PbX2 thin film substrate using the AY thin film nanoimprint to obtain an APb(X,Y)3 perovskite patterned thin film; wherein X and Y are independently one or more of I, Br, and Cl, and the AY salt includes amine salts and / or Cs-based salts.

[0028] This invention addresses the patterning technology of perovskite thin films / single crystals, targeting optoelectronic applications such as light emission, detection, and photovoltaics. Based on the unique film formation method of perovskite materials—namely, the two-step ion intercalation film formation—a unique "in-situ two-step synthesis method" for perovskite patterning based on nanoimprinting is designed to achieve the fabrication of coplanar perovskite patterned structures. Specifically, as... Figure 1 and Figure 2 As shown, the process involves coating a PbX2 precursor film S1. First, a PbX2 precursor is coated onto a pre-fabricated substrate, followed by a first annealing to obtain a PbX2 film substrate with good and stable substrate contact. This substrate includes substrate A and PbX2 1 coated thereon. Then, an AY salt film S2 is coated onto a pre-fabricated patterned nanostamp, followed by a second annealing. At this point, both the protruding and recessed portions of the nanostamp will be deposited with AY film, resulting in an AY film nanostamp, comprising nanostamp B and AY salt 2 coated thereon. The protruding portions of the nanostamp represent the desired perovskite pattern.

[0029] Finally, nanoimprinting (S3) is performed. The PbX2 film substrate is nanoimprinted using an AY film nanostamp. The protruding AY film of the nanostamp contacts the PbX2 film on the substrate, allowing AY to diffuse effectively within the PbX2 film and generate perovskite. Taking full advantage of the ion migration characteristics of organolead halide perovskite materials and the wide-bandgap inertness of the precursor PbX2, the nanostamp serves as the diffusion substrate for the AY salt. Through a combination of contact imprinting and ion diffusion, a perovskite pattern is precisely constructed on the PbX2 substrate, successfully forming a coplanar structure of PbX2 / perovskite / PbX2. The perovskite pattern acts as the active region, while the remaining PbX2 naturally serves as a wide-bandgap insulating / inert barrier material. After the diffusion reaction is complete, the nanostamp can be directly removed to obtain an APb(X,Y)3 perovskite patterned film C protected by inert wide-bandgap PbX2. The patterned portion is the generated perovskite APb(X,Y)3.

[0030] After fabrication, a top transport layer D and a driving unit E, such as a driving electrode or driving circuit, can be set on the perovskite patterned thin film as needed to obtain a patterned optical device, such as a perovskite Micro-LED F, which can emit light G through the driving unit.

[0031] The preparation method of this invention is a unique patterning method for perovskite materials. Its core utilizes two key aspects: the high ion mobility of perovskite and the wide-bandgap photoelectric inertness of the precursor PbX2. Through a two-step synthesis method, perovskite patterns are grown in situ, fundamentally avoiding the residue and peeling problems easily encountered in traditional nanoimprinting methods. The resulting pattern has a low residual rate and significantly improved yield. Moreover, the preparation method is simple, and the prepared perovskite patterned film is a coplanar film with negligible undulations. Subsequent patterning, pixelation, and arraying of optoelectronic devices can be further assembled without any planarization treatment, facilitating the fabrication of subsequent optoelectronic devices. It can be applied to various optoelectronic devices such as Mini / Micro-LEDs, solar cells, and photodetectors, demonstrating a wide range of applications.

[0032] In a preferred embodiment, the PbX2 precursor includes PbX2 and / or PbX2 derivatives, including coordination compounds such as PbX2-DMSO and / or PbX2-NMP. The selection of the aforementioned PbX2 precursor is based on two main points: firstly, the PbX2 precursor is an essential reaction precursor for perovskite materials, providing a precursor matrix for the subsequent two-step nanoimprinting process; secondly, the aforementioned PbX2 precursor is a wide-bandgap semiconductor material, naturally capable of forming an electrically insulating layer and possessing good photoelectric inertness, thereby simplifying the fabrication process of subsequent optoelectronic devices. Based on these reasons, the yield of perovskite patterns can be further improved. Depending on the raw materials, the coating method for the PbX2 precursor can be selected from conventional methods, including but not limited to spin coating, blade coating, slot coating, and vacuum evaporation.

[0033] The aforementioned AY salts include a series of materials such as amine salts and Cs-based salts that can meet the tolerance factor of ABX3 perovskite. In a preferred embodiment, the AY salt includes one or more of MAY (methylamine salt), FAY (formamidinium salt), and CsY. These AY salts are readily available and have lower costs, exhibiting better ion migration capabilities in PbX2 precursor films, thereby further improving the yield of perovskite patterns. Depending on the raw materials, the coating method for the AY salt can be selected from conventional methods, including but not limited to spin coating, blade coating, slot coating, and vacuum evaporation.

[0034] The aforementioned substrate materials include, but are not limited to, one or more of various insulating, semiconductor, and other organic or inorganic materials. In a preferred embodiment, the substrate material includes one or more of transparent conductive glass, oxides, and organic polymers, and the nanoprint material includes one or more of PDMS, PMMA, and Al2O3. The aforementioned nanoprint material has better wettability, which can further ensure that the coated AY film is sufficiently uniform. The pattern of the nanoprint can be prepared using common pattern etching processes such as photolithography or electron beam etching.

[0035] Preferably, the transparent conductive glass includes one or more of ITO, FTO, and IZO; the oxide includes one or more of Al2O3, TiO2, SnO2, and ZnO; and the organic polymer material includes one or more of PMMA, PDMS, and PEIE. These substrate materials have better wettability, which further ensures that a uniform and dense PbX2 film can be obtained on them. More preferably, the substrate material is one or more of ITO, ZnO, and PEIE, which has better compatibility with the PbX2 of this invention. Furthermore, to meet the requirements of subsequent optoelectronic device fabrication, the substrate can be a pre-fabricated device structure.

[0036] In a preferred embodiment, in step S1, the temperature of the first annealing is 60–80°C, and the time is 0.5–2 min. This annealing process yields a PbX2 film with better contact with the substrate, further increasing the stability of the PbX2 film substrate.

[0037] Accordingly, in a preferred embodiment, in step S2, the temperature of the second annealing is 50-70°C and the time is 0.5-2 min, so that the protruding and recessed portions of the nanoprint are deposited more fully and uniformly as an AY film.

[0038] Preferably, before coating with AY salt, the process further includes a step of hydrophilic treatment on the surface of the patterned nano stamp; more preferably, the hydrophilic treatment is a process of treating with ultraviolet light and ozone for 5 to 15 minutes. The hydrophilic treatment can further improve the wettability of the nano stamp surface, resulting in a more uniformly coated AY film, which facilitates the smooth formation of the pattern during the subsequent imprinting reaction.

[0039] The applied pressure in the above nanoimprinting method can be adjusted according to different perovskite compositions. In a preferred embodiment, in step S3, the applied pressure of nanoimprinting is 0-100 MPa, preferably 0.5-2 MPa, and the applied pressure time is 0.5-2 min. This allows the AY film on the nanoimprint surface to have more sufficient contact with the PbX2 film on the substrate surface, thereby allowing AY to diffuse more reasonably in the PbX2 film and further smoothly forming a smooth coplanar structure of PbX2 / perovskite / PbX2.

[0040] Preferably, step S3 further includes a third annealing. The annealing regime can be adjusted as needed for different perovskite compositions. More preferably, the temperature of the third annealing is 70–300°C, preferably 80–120°C, and the time is 3–7 min, which can further accelerate ion migration and perovskite phase formation in the AY film. It should be noted that, depending on different experimental environments and conditions, those skilled in the art can choose to perform the third annealing during the nanoimprinting process or after imprinting.

[0041] In another typical embodiment of the present invention, a perovskite patterned thin film is also provided, which is obtained by the preparation method of the present invention, wherein the perovskite pattern serves as the active region, while the remaining PbX2 naturally serves as a wide-bandgap insulating / inert barrier material. The perovskite patterned thin film has almost no residue and a high yield.

[0042] In another typical embodiment of the present invention, the application of the above-mentioned perovskite patterned thin film in optoelectronic devices is also provided, including but not limited to applications in Mini / Micro-LEDs, solar cells, photodetectors, and other optoelectronic devices. The above-mentioned perovskite patterned thin film can be further used to prepare subsequent transport layers or functional layers to construct optoelectronic devices. Since the APb(X,Y)3 perovskite / PbX2 patterned thin film obtained by the imprinting method of the present invention is almost a coplanar film with negligible undulations, no subsequent planarization treatment is required before coating the transport layer. Further combining it with patterned electrodes or driving electrodes yields patterned, pixelated, and arrayed optoelectronic devices.

[0043] In another typical embodiment of the present invention, an optoelectronic device is also provided, comprising the above-described perovskite patterned thin film; preferably, the optoelectronic device is a solar cell, Micro-LED, Mini-LED or OLED.

[0044] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0045] Example 1: MAPbI3 Patterned Thin Film

[0046] The first step involved preparing the PbI2 thin film substrate and the MAI thin film nanoprint. A 0.5M PbI2 solution (DMF:DMSO = 9:1 solvent) was spin-coated onto the prepared ITO / ZnO / PEIE composite transparent conductive substrate using spin-coating parameters of 1500 rpm, 1000 rpm / s, and 30 s. After spin-coating, an annealing process at 70°C for 1 min was performed to complete the preparation of the PbI2 thin film substrate. For the preparation of the MAI thin film, the PMMA nanoprint surface was first treated with UV ozone for 10 min to improve surface wettability. Then, a 3M MAI IPA solution was spin-coated onto the PMMA nanoprint surface using spin-coating parameters of 2000 rpm, 1000 rpm / s, and 60 s. After spin-coating, an annealing process at 60°C for 1 min was performed to complete the preparation of the MAI thin film nanoprint.

[0047] The second step involves preparing a patterned MAPbI3 film using perovskite nanoimprinting. A substrate coated with a PbI2 film is brought into contact with a nanoimprint coated with a MAI film, and a pressure of 0.5 MPa is applied for 1 minute. This is followed by annealing at 100°C for 5 minutes. After annealing, the nanoimprint is separated from the substrate to obtain the patterned perovskite MAPbI3 film.

[0048] The third step is the fabrication of LED devices based on patterned MAPbI3 thin films. A TPB transport layer is coated on the patterned perovskite MAPbI3 thin film, and a 7 nm MoO3 hole transport (blocking layer) is deposited. Subsequently, an 80 nm Au electrode is deposited as the driving electrode to obtain a patterned MAPbI3 red LED device.

[0049] Photographs of the Micro-LED device with perovskite patterned thin films prepared in Example 1 are shown below. Figure 3 .

[0050] Example 2

[0051] The difference between Example 2 and Example 1 is that in the first step, the precursor PbI2 of the MAPbI3 thin film is replaced with PbBr2, and MAI is replaced with MABr, to obtain a perovskite MAPbBr3 patterned thin film and a patterned MAPbBr3 green LED device.

[0052] Example 3

[0053] The difference between Example 3 and Example 1 is that in the third step, the entire Au electrode is replaced with a driving electrode with a corresponding pattern, resulting in a perovskite MAPbI3 patterned thin film and a perovskite Micro-LED device with a controllable driving circuit.

[0054] Example 4

[0055] The difference between Example 4 and Example 1 is that in the first step, the concentration of PbI2 precursor is increased to 1.3M, and ZnO / PEIE is replaced with SnO2. In the third step, the TFB / MoO3 transport layer is replaced with Spiro-OMeTAD, resulting in a perovskite MAPbI3 patterned thin film and a patterned MAPbI3 solar cell device.

[0056] Example 5: MAPbI3 Patterned Thin Film

[0057] The first step involved preparing the PbI2 thin film substrate and the MAI thin film nanoprint. A 0.5M PbI2 solution (DMF:DMSO = 9:1 solvent) was spin-coated onto the prepared ITO / ZnO / PEIE composite transparent conductive substrate using spin-coating parameters of 1500 rpm, 1000 rpm / s, and 30 s. After spin-coating, an annealing process at 60°C for 2 minutes was performed to complete the preparation of the PbI2 thin film substrate. For the preparation of the MAI thin film, the PMMA nanoprint surface was first treated with UV ozone for 5 minutes to improve surface wettability. Then, a 3M MAI IPA solution was spin-coated onto the PMMA nanoprint surface using spin-coating parameters of 2000 rpm, 1000 rpm / s, and 60 s. After spin-coating, an annealing process at 50°C for 2 minutes was performed to complete the preparation of the MAI thin film nanoprint.

[0058] The second step involves preparing a patterned MAPbI3 thin film using perovskite nanoimprinting. A substrate coated with a PbI2 film is brought into contact with a nanoimprint coated with a MAI film, and a pressure of 0.5 MPa is applied for 2 minutes. This is followed by annealing at 80°C for 7 minutes. After annealing, the nanoimprint is separated from the substrate to obtain the patterned perovskite MAPbI3 thin film.

[0059] The third step is the fabrication of LED devices based on patterned MAPbI3 thin films. A TPB transport layer is coated on the patterned perovskite MAPbI3 thin film, and a 7 nm MoO3 hole transport (blocking layer) is deposited. Subsequently, an 80 nm Au is deposited as the driving electrode to obtain a patterned MAPbI3 red LED device.

[0060] Example 6: MAPbI3 Patterned Thin Film

[0061] The first step involved preparing the PbI2 thin film substrate and the MAI thin film nanoprint. A 0.5M PbI2 solution (DMF:DMSO = 9:1 solvent) was spin-coated onto the prepared ITO / ZnO / PEIE composite transparent conductive substrate. The spin-coating parameters were 1500 rpm, 1000 rpm / s, and 30 s. After spin-coating, an annealing process was performed at 80°C for 0.5 min to complete the preparation of the PbI2 thin film substrate. For the preparation of the MAI thin film, the PMMA nanoprint surface was first treated with UV ozone for 15 min to improve surface wettability. Then, a 3M MAI IPA solution was spin-coated onto the PMMA nanoprint surface. The spin-coating parameters were 2000 rpm, 1000 rpm / s, and 60 s. After spin-coating, an annealing process was performed at 70°C for 0.5 min to complete the preparation of the MAI thin film nanoprint.

[0062] The second step involves preparing a patterned MAPbI3 thin film using perovskite nanoimprinting. A substrate coated with a PbI2 film is brought into contact with a nanoimprint coated with a MAI film, and a pressure of 2 MPa is applied for 0.5 min. This is followed by annealing at 120°C for 3 min. After annealing, the nanoimprint is separated from the substrate to obtain the patterned perovskite MAPbI3 thin film.

[0063] The third step is the fabrication of LED devices based on patterned MAPbI3 thin films. A TPB transport layer is coated on the patterned perovskite MAPbI3 thin film, and a 7 nm MoO3 hole transport (blocking layer) is deposited. Subsequently, an 80 nm Au is deposited as the driving electrode to obtain a patterned MAPbI3 red LED device.

[0064] Comparative Example 1

[0065] This example illustrates a method for preparing patterned CH3CH3PbI3 thin films on electronic-grade glass substrates, specifically including the following steps:

[0066] Step 1: Cut a 3cm x 3cm square from the CD-ROM, remove the protective layer directly, and mark the front and back. Wash away the light green dye on the surface with ethanol, immerse the CD in ethanol, ultrasonically clean for 15 minutes, remove and dry for later use;

[0067] Step 2: Weigh 2g of PDMS main agent and 0.2g of curing agent, mix and stir thoroughly, then coat the surface of CD-ROM raster layer, place in a drying oven, dry at 60℃ for 10 hours, and demold to obtain CD-PDMS stamp based on CD-ROM channel pattern;

[0068] Step 3: Prepare a 0.9 mol / L PbI2 solution using DMF as the solvent, and heat it to 65°C under a nitrogen atmosphere while stirring for 40 min.

[0069] Step 4: Take a 2cm×2cm electronic-grade glass slide, and ultrasonically clean it in the following order: detergent, deionized water, acetone, and isopropanol for 20 minutes each. After cleaning, remove and dry the slide. Then, perform ultraviolet cleaning on the glass slide for 15 minutes.

[0070] Step 5: In a nitrogen atmosphere, spin-coat the PbI2 solution onto an electronic-grade glass slide at 2500 rpm for 3 seconds.

[0071] Step 6: Imprint the semi-wet PbI2 film with a CD-PDMS pattern stamp for 10 seconds.

[0072] Step 7: Slowly demold the imprinted PbI2 film and place the glass substrate on a heating table to anneal at 100°C for 10 minutes.

[0073] Step 8: Take 0.6g of CH3CH2I particles and grind them into powder;

[0074] Step 9: Place the annealed PbI2 film in a glass dish, evenly sprinkle CH3CH3I powder around the film, and cover it. Place the glass dish on a heating plate and heat to 160℃ for 3 hours. After the reaction is complete, remove the dish to obtain the patterned CH3CH2PbI3 film.

[0075] Comparative Example 2

[0076] This example illustrates a method for preparing patterned CH3CH3PbI3 thin films on a quartz SiO2 substrate, specifically including the following steps:

[0077] Step 1: Clean the quartz SiO2 substrate with acetone and isopropanol and then treat it with ultraviolet ozone for 15 minutes to improve the wettability of the substrate.

[0078] Step 2: A DMSO precursor solution of CH3CH3PbI3 with a mass fraction of 30wt% was spin-coated onto a SiO2 substrate at room temperature at 3000 rpm for 30s. Then, a patterned PDMS substrate was pressed onto the CH3CH3PbI3 liquid film and a pressure of 25 kPa was applied.

[0079] Step 3: Anneal the imprinted sample at 80°C for 15 min to complete the preparation of the patterned CH3CH3PbI3 thin film.

[0080] The residual rate of perovskite patterned thin films and the LED device fabrication yield in Examples 1 to 6 and Comparative Examples 1 and 2 are shown in Table 1.

[0081] Test method:

[0082] Residual rate: Since the residue is also a light-emitting semiconductor material, the residual rate between different patterning methods can be compared by observing and calculating the proportion of the light-emitting residue occupying the area that should not appear by confocal fluorescence microscopy.

[0083] Yield: Based on the fabrication of 20 LED light-emitting devices for each patterning method and testing whether they can work, the ratio of the number of working LED devices to the total number of fabricated devices is defined as the yield of the patterning method.

[0084] Table 1

[0085] Residual rate Yield Example 1 1.0％ 100％ Example 2 0.5％ 95％ Example 3 0.2％ 100％ Example 4 0.7％ 100％ Example 5 1.4％ 90％ Example 6 1.3％ 90％ Comparative Example 1 8.0％ 80％ Comparative Example 2 12.0％ 65％

[0086] As can be seen from the above, compared with the comparative examples, the embodiments of the present invention fully utilize the ion migration characteristics of organolead halide perovskite materials and the wide bandgap inertness of the precursor PbX2. Using nanostamps as the diffusion substrate for AY salts, perovskite patterns are precisely constructed on the PbX2 substrate through a combination of contact imprinting and ion diffusion, thus successfully forming a coplanar structure of PbX2 / perovskite / PbX2. The perovskite pattern serves as the active region, while the remaining PbX2 naturally acts as a wide bandgap insulating / inert barrier material. This fundamentally avoids the residue and peeling problems that are prone to occur in traditional nanoimprinting methods, resulting in a low pattern residue rate and significantly improved yield. Moreover, the preparation method is simple, and the resulting perovskite patterned film is a coplanar, smooth film that can be directly used for the fabrication of optoelectronic devices without any subsequent planarization treatment. It can be applied to various optoelectronic devices such as Mini / Micro-LEDs, solar cells, and photodetectors, and has a wide range of applications.

[0087] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a perovskite patterned thin film, characterized in that, Includes the following steps: Step S1: Coat the PbX2 precursor on the substrate and perform a first annealing to obtain a PbX2 thin film substrate. Step S2: Coat the patterned nanoprint with AY salt and perform a second annealing to obtain an AY thin film nanoprint. Step S3: The PbX2 film substrate is nanoimprinted using the AY film nanoprinter, and then subjected to a third annealing to obtain an APb(X,Y)3 perovskite patterned film. Wherein, X and Y are independently one or more of I, Br and Cl, and the AY salt includes amine salts and / or Cs-based salts; the nanoimprinting is applied at a pressure of 0.5~2 MPa for 0.5~2 min; and the third annealing is performed at a temperature of 80~120℃ for 3~7 min.

2. The preparation method according to claim 1, characterized in that, The PbX2 precursor includes PbX2 and / or PbX2 derivatives, and the PbX2 derivatives include PbX2-DMSO and / or PbX2-NMP.

3. The preparation method according to claim 1 or 2, characterized in that, The AY salt includes one or more of MAY, FAY, and CsY.

4. The preparation method according to claim 1 or 2, characterized in that, The substrate material includes one or more of transparent conductive glass, oxides, and organic polymers, and the nanoprint material includes one or more of PDMS, PMMA, and Al2O3.

5. The preparation method according to claim 4, characterized in that, The transparent conductive glass includes one or more of ITO, FTO, and IZO; the oxide includes one or more of Al2O3, TiO2, SnO2, and ZnO; and the organic polymer material includes one or more of PMMA, PDMS, and PEIE.

6. The preparation method according to claim 5, characterized in that, The substrate is made of one or more of ITO, ZnO, and PEIE.

7. The preparation method according to claim 1 or 2, characterized in that, In step S1, the temperature of the first annealing is 60~80℃ and the time is 0.5~2 min.

8. The preparation method according to claim 1 or 2, characterized in that, In step S2, the temperature of the second annealing is 50~70℃, and the time is 0.5~2 min.

9. The preparation method according to claim 1 or 2, characterized in that, Prior to coating with the AY salt, the process includes a step of hydrophilic treatment of the surface of the patterned nanoprint.

10. The preparation method according to claim 9, characterized in that, The hydrophilic treatment involves ultraviolet and ozone treatment for 5-15 minutes.

11. A perovskite patterned thin film, characterized in that, It is obtained by the preparation method according to any one of claims 1 to 10.

12. The application of the perovskite patterned thin film of claim 11 in optoelectronic devices.

13. An optoelectronic device, characterized in that, Includes the perovskite patterned thin film as described in claim 11.

14. The optoelectronic device according to claim 13, characterized in that, The optoelectronic device is a solar cell, Micro-LED, Mini-LED, or OLED.

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