Preparation method of horizontal guiding CsPbBr3 nanowire array

Abstract

The invention relates to the technical field of nano materials, and discloses a preparation method of a horizontal guiding CsPbBr3 nanowire array. The preparation method comprises the following steps: S1, blade-coating a mixture containing polydimethylsiloxane on a channel array template, heating, curing and stripping to obtain a polydimethylsiloxane film with a channel array; s2, cleaning a substrate and performing hydrophobic modification to obtain a hydrophobic substrate; s3, a CsPbBr3 solution is taken, a surfactant is added, and a mixed solution is obtained; and S4, dropwise adding the mixed solution to the surface of a hydrophobic substrate, covering a polydimethylsiloxane film with a channel array, compacting, heating, and stripping to obtain the horizontal guiding CsPbBr3 nanowire array. The preparation method of the horizontally oriented CsPbBr3 nanowire array provided by the invention is simple in steps, short in time consumption and high in efficiency, and the obtained CsPbBr3 nanowire array is tidy in horizontal arrangement, good in continuity and high in crystallization quality.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterials, and in particular to a horizontally oriented CsPbBr 3 Method for preparing nanowire arrays. Background Art

[0002] Perovskites have excellent optoelectronic properties, such as high absorption coefficient, long carrier lifetime, low defect density, wide band gap adjustable range, etc. Among them, organic-inorganic halide perovskites are unstable, but cesium-containing halide perovskites have the advantages of emission adjustability and easy synthesis, and their stability is also greatly improved. In recent years, inorganic semiconductors composed of strong covalent bonds between atoms have attracted more and more attention, such as CsPbBr 3 is one of them. At present, there are many reports on the synthesis of CsPbBr 3 Single crystal thin films are used to prepare solar cells or use quantum dots to build lasers, but by synthesizing single crystal CsPbBr 3 There are still few reports on nanowires being suitable for device integration. The main problem is how to integrate and arrange the synthesized nanowires on-chip and simplify the equipment and synthesis steps as much as possible to adapt to large-scale production.

[0003] As a one-dimensional structure, nanowires have excellent material quality and outstanding electrical, optical and optoelectronic properties. Aligning the growth direction of nanowires can not only make the performance of nanowire devices a qualitative leap compared to randomly distributed nanowires, but also greatly simplify the processing technology of nanowire devices and help achieve large-scale device integration. Existing methods for preparing guided nanowires include vapor deposition, solution coating, AAO template-assisted method and solution direct synthesis. These methods can obtain horizontal nanowire arrays with certain guidance, but all have high requirements for the preparation environment. For example, the vapor deposition method needs to be carried out under high temperature and low pressure conditions, and the growth and arrangement of nanowires cannot be carried out simultaneously. After the growth of the nanowires, transfer and alignment work is required, which requires high equipment and the process is relatively complicated. Summary of the invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, one of the purposes of the present invention is to provide a horizontally guided CsPbBr 3 A method for preparing a nanowire array; a second object of the present invention is to provide a horizontally directed CsPbBr nanowire array prepared by the preparation method 3 Applications of nanowire arrays.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect of the present invention provides a horizontally directed CsPbBr 3The method for preparing a nanowire array comprises the following steps:

[0007] S1, applying a mixture containing polydimethylsiloxane to a channel array template by scraping, heating and curing, and peeling off to obtain a polydimethylsiloxane film with a channel array;

[0008] S2, cleaning the substrate and performing hydrophobic modification to obtain a hydrophobic substrate;

[0009] S3, take CsPbBr 3 solution, adding a surfactant to obtain a mixed solution;

[0010] S4, dropping the mixed solution onto the surface of a hydrophobic substrate, covering the polydimethylsiloxane film with a channel array, compacting, heating, and peeling off to obtain a horizontally oriented CsPbBr 3 Nanowire arrays.

[0011] Preferably, in step S1, the channel array template comprises one of a DVD disc polycarbonate plate and an M-plane sapphire; further preferably, the channel array template is a single-layer recording layer DVD disc polycarbonate plate.

[0012] Preferably, the DVD disc polycarbonate plate is obtained by a method comprising the following steps:

[0013] (1) peeling off the protective layer (printing layer) of the DVD disc to obtain a polycarbonate plate covered with a metal reflective layer and a photosensitive dye layer;

[0014] (2) peeling off the metal reflective layer with an adhesive tape to obtain a polycarbonate plate covered with a photosensitive dye layer;

[0015] (3) The polycarbonate plate covered with the photosensitive dye layer is immersed in an ethanol aqueous solution (ethanol: water = 1:1, v / v), and the dye in the photosensitive dye layer is wiped off with dust-free paper to obtain a transparent DVD disc polycarbonate plate.

[0016] Preferably, the channel array template can be cut into any size and shape.

[0017] Preferably, in the step S1, the polydimethylsiloxane-containing mixture includes polydimethylsiloxane (PDMS) and a curing agent.

[0018] Preferably, the mass ratio of the dimethylsiloxane to the curing agent is (8-12):1; further preferably, the mass ratio of the dimethylsiloxane to the curing agent is (9-11):1.

[0019] Preferably, the curing agent includes an organosilicon curing agent; further preferably, the curing agent is Dow Corning Sylgard 184.

[0020] Preferably, in the step S1, the temperature of the heating and curing is 55-65°C; more preferably, the temperature of the heating and curing is 57-62°C.

[0021] Preferably, in step S1, the heating and curing time is 1.5 to 2.5 hours; more preferably, the heating and curing time is 1.7 to 2.2 hours.

[0022] Preferably, the polydimethylsiloxane film can be cut into any shape and size, and the shape and size of the substrate are the same as those of the polydimethylsiloxane film, thereby realizing CsPbBr 3 Control of the size and shape of nanowire arrays.

[0023] Preferably, in step S2, the substrate comprises one of glass, silicon wafer and sapphire.

[0024] Preferably, in step S2, the reagents used for cleaning the substrate include ketone solvents, alcohol solvents and water; further preferably, the reagents used for cleaning the substrate include acetone, 95% ethanol and water.

[0025] Preferably, in step S2, the specific operation of cleaning the substrate is: ultrasonic cleaning with ketone solvent, alcohol solvent and water in sequence, the ultrasonic power is 130-140W, and the cleaning time is 8-12min / time.

[0026] Preferably, in step S2, after the cleaning is completed, a gas drying step is also included; further preferably, after the cleaning is completed, N 2 Blow dry the substrate to remove any residual moisture and stains to obtain a clean substrate.

[0027] Preferably, in step S2, the hydrophobic modification comprises sequentially performing plasma cleaning and soaking in a mixed solution of n-hexane and octadecyltrichlorosilane.

[0028] Preferably, the specific operation of the plasma cleaning is: placing the clean substrate into a vacuum plasma cleaning machine for cleaning.

[0029] Preferably, the plasma cleaning time is 250 to 350 seconds; further preferably, the plasma cleaning time is 270 to 320 seconds.

[0030] Specifically, plasma cleaning refers to the work of treating the surface of a substrate by plasma. The energy of plasma particles is between 0 and 20 eV. When acting on the surface of the substrate, the original chemical bonds are broken, and the free radicals in the plasma form a new structure with it, bringing about the effect of surface activation and modification. Through plasma cleaning, impurities on the surface of the substrate can be further removed, and polar groups hydroxyl groups (-OH) can be introduced on the surface of the substrate.

[0031] Preferably, the volume ratio of n-hexane to octadecyltrichlorosilane is (900-1100):1; further preferably, the volume ratio of n-hexane to octadecyltrichlorosilane is (950-1050):1.

[0032] Preferably, the soaking time is 1.5 to 2.5 hours; further preferably, the soaking time is 1.7 to 2.2 hours.

[0033] Specifically, octadecyltrichlorosilane (OTS) is an alkyl silane that can form strong covalent bonds with silicon oxide, functionalize the surface of various nanoparticles and promote the formation of hydrophobic coatings with high water contact angles and low surface energy. OTS can react with hydroxyl groups to form polyoctadecylsiloxane (PODS) to achieve hydrophobic treatment of the substrate.

[0034] Preferably, after the immersion is completed, the method further comprises the steps of using a ketone solvent to remove the residual solution on the surface of the substrate and performing gas drying.

[0035] Preferably, in step S3, the CsPbBr 3 The concentration of the solution is 0.1-0.3 mol / L; further preferably, the CsPbBr 3 The concentration of the solution is 0.15 to 0.25 mol / L; more preferably, the CsPbBr 3 The concentration of the solution is 0.2 mol / L. If the concentration of the solution is too high, the solute crystals cannot form wires and form a film, while if the concentration is too low, the material for the growth of nanowires is insufficient, resulting in a reduction in the size and density of the nanowires.

[0036] Preferably, the CsPbBr 3 The raw materials for the preparation of the solution include CsBr, PbBr 2 and dimethyl sulfoxide (DMSO); the CsBr and PbBr 2 The amount of substance ratio is 1:1.

[0037] Preferably, in step S3, the surfactant and CsPbBr 3 The mass ratio of the solution is 1:(15-25); further preferably, the surfactant and CsPbBr 3 The mass ratio of the solution is 1:(17-22); more preferably, the surfactant and CsPbBr 3 The mass ratio of the solution is 1:20.

[0038] Preferably, in step S3, the surfactant includes polyvinyl pyrrolidone (PVP). As a surfactant, polyvinyl pyrrolidone can control the growth direction and morphology of perovskite nanowires, improve their crystallinity and uniformity, and change the electronic structure and band gap of nanowires, thereby improving their optical and electrical properties.

[0039] Preferably, in step S4, compaction is performed by pressing with tweezers, placing weights, etc., so that the polydimethylsiloxane film and the hydrophobic substrate are better fitted.

[0040] Specifically, since both the upper and lower substrates are hydrophobic surfaces, they have a certain repulsion to the solution, which will cause the PDMS to be suspended above the solution, making it impossible to meet the spatial restriction requirements for the solution. At the same time, due to the hydrophobicity of the substrate, the solution is concentrated in one place, and it is impossible to form a large area of ​​uniform CsPbBr on the substrate. 3 Nanowires, so the compaction operation can make the upper and lower substrates fit better, making the solution distribution more uniform, and obtaining a large area of ​​uniform CsPbBr 3 The key to nanowires.

[0041] Preferably, in step S4, the heating temperature is 60-80° C., more preferably, the heating temperature is 70-80° C., and even more preferably, the heating temperature is 75° C. If the evaporation temperature is too high, the nucleation rate is too fast, resulting in a large number of defects in the nanowires.

[0042] Preferably, in step S4, the heating time is 3 to 5 hours; further preferably, the heating time is 3.5 to 4.5 hours; further preferably, the heating time is 4 hours.

[0043] The second aspect of the present invention provides a horizontally oriented CsPbBr prepared by the preparation method described in the first aspect of the present invention. 3 Application of nanowire arrays in the preparation of optoelectronic devices.

[0044] Preferably, the optoelectronic device comprises a photodetector, a pixel sensor and a phototransistor.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1) The horizontally oriented CsPbBr 3 The preparation method of the nanowire array has simple steps. Through template replication, a nanoscale channel array for guiding the growth of nanowires can be formed on the surface of the polydimethylsiloxane film; by hydrophobic treatment of the substrate, the solution can be prevented from penetrating and diffusing to form a film during the growth of the nanowires; by 3Adding surfactant to the solution can better control the growth direction and morphology of nanowires and improve their crystallinity and uniformity. 3 The nanowire arrays are neatly arranged horizontally, have good continuity and high crystal quality.

[0047] 2) The horizontally oriented CsPbBr 3 The preparation method of nanowire array realizes the simultaneous growth and arrangement of nanowires, has low equipment requirements, easy-to-obtain substrate materials, and low cost. Compared with vapor deposition and other methods, horizontally oriented CsPbBr can be prepared at a lower temperature of 60 to 80 ° C and normal pressure. 3 Nanowire array, short time consumption and high efficiency.

[0048] 3) The horizontally guided CsPbBr 3 The method for preparing a nanowire array has the length of the obtained nanowires ranging from several hundred micrometers to several millimeters, with neat arrangement and high uniformity. The array area is controllable. When used to prepare optoelectronic devices such as transistors, there is no need to prepare dielectric layers and gates. The application is simple and helps to achieve large-scale device integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of the structure of a single-layer recording layer DVD disc used in the embodiments and comparative examples;

[0050] Figure 2 It is a schematic diagram of the process flow chart for preparing PDMS film;

[0051] Figure 3 For horizontally oriented CsPbBr 3 Schematic diagram of the nanowire array growth process;

[0052] Figure 4 is a scanning electron microscope image of the PDMS film with a channel array in Example 1;

[0053] Figure 5 The water contact angle images of the glass substrate before (a) and after (b) the hydrophobic treatment in Example 1;

[0054] Figure 6 The horizontally oriented CsPbBr in Example 1 3 Optical microscope image of the nanowire array at 50 times magnification;

[0055] Figure 7 The horizontally oriented CsPbBr in Example 1 3 Optical microscope image of the nanowire array magnified 100 times;

[0056] Figure 8 The horizontally oriented CsPbBr in Example 13 Optical microscope image of the nanowire array magnified 1000 times;

[0057] Fig. 9 The horizontally oriented CsPbBr in Example 1 3 Optical microscope image of the nanowire array magnified 5000 times;

[0058] Fig.10 For the horizontally oriented CsPbBr in Example 2 3 Optical microscope image of the nanowire array at 50 times magnification;

[0059] Fig.11 For the horizontally oriented CsPbBr in Comparative Example 2 3 Optical microscope image of the nanowire array at 50 times magnification;

[0060] Fig.12 For the horizontally oriented CsPbBr in Comparative Example 1 3 Optical microscope image of the nanowire array magnified 5000 times. DETAILED DESCRIPTION

[0061] The present invention is further described in detail below by specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial sources or can be obtained by prior art methods. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0062] Figure 1 Schematic diagram of the structure of a single-layer recording layer DVD disc used in the embodiments and comparative examples, Figure 1 It can be seen that the single-layer recording layer DVD disc includes a protective layer, a metal reflective layer, a photosensitive dye layer and a polycarbonate plate. 3 When forming a nanowire array, the protective layer, metal reflective layer, and photosensitive dye layer need to be peeled off layer by layer to obtain a polycarbonate plate as a channel array template. Figure 2 This is a schematic diagram of the PDMS film preparation process. Figure 3 For horizontally oriented CsPbBr 3 Schematic diagram of the nanowire array growth process. Figure 1 , Figure 2 and Figure 3 For horizontally oriented CsPbBr 3 The preparation process of the nanowire array is described. In the examples and comparative examples, the heating curing is carried out on a BY-1010 heating table of Bangyuan Electronics Co., Ltd.:

[0063] Example 1

[0064] This example prepares a horizontally oriented CsPbBr3 Nanowire array, the steps are:

[0065] S1. Tear off the protective layer of the DVD disc to obtain a polycarbonate plate covered with a metal reflective layer and a photosensitive dye layer, peel off the metal reflective layer with tape to obtain a polycarbonate plate covered with a photosensitive dye layer, immerse the polycarbonate plate covered with the photosensitive dye layer in an ethanol aqueous solution (ethanol: water = 1:1, v / v), take out and wipe off the dye in the photosensitive dye layer with a dust-free paper to obtain a transparent DVD disc polycarbonate plate; apply a mixture containing polydimethylsiloxane (PDMS and Dow Corning Sylgard184 curing agent, mass ratio 1:1) on the surface of the DVD disc polycarbonate plate, place it on a heating table at 60°C for 2 hours to cure, and obtain a PDMS film with a replica of the disc channel array, which is cut into a size of 1 cm×1 cm;

[0066] S2. Cut the glass slide into 1 cm × 1 cm size, and clean it with acetone, 95% ethanol, and deionized water in sequence, with an ultrasonic power of 135 W and a time of 10 min each time, and then blow dry the substrate with nitrogen to remove residual moisture and stains;

[0067] S3, put the cleaned glass into a plasma cleaning machine for 300 seconds, further remove surface impurities and introduce polar groups such as hydroxyl (-OH) on the substrate surface to make the surface hydrophilic, then take 10mL of n-hexane and 10μL of OTS solution to prepare a mixed solution, put the glass substrate into the solution and seal it for 2 hours to achieve surface hydrophobic treatment; after the hydrophobic treatment is completed, quickly remove the residual solution on the surface with acetone, and blow dry with nitrogen to obtain a hydrophobic glass substrate;

[0068] S4, mix CsBr and PbBr in a 1:1 ratio 2 Put it into the reagent bottle containing DMSO solution to make a 0.2 mol / L concentration of CsPbBr 3 solution, and then weigh 5% CsPbBr 3 Add solution-quality PVP powder into the solution and mix it. After sealing, stir the solution with a stirring bar to fully dissolve it.

[0069] S5. Place the hydrophobic glass substrate on the heating table and take 10uL CsPbBr 3 The mixed solution with PVP was dripped onto the hydrophobic glass substrate, and then the PDMS film obtained in step S1 was quickly covered on the hydrophobic glass substrate, with the side with the replica channel facing the substrate, and the PDMS film was gently pressed to make it fit with the hydrophobic glass substrate. The heating temperature of the heating table was set to 75 ° C, and the heating time was 4 h. After the heating was completed, the PDMS film was gently lifted to obtain the horizontally oriented CsPbBr 3Nanowire arrays.

[0070] Example 2

[0071] This example prepares a horizontally oriented CsPbBr 3 Nanowire array, the steps are:

[0072] S1. Tear off the protective layer of the DVD disc to obtain a polycarbonate plate covered with a metal reflective layer and a photosensitive dye layer, peel off the metal reflective layer with tape to obtain a polycarbonate plate covered with a photosensitive dye layer, immerse the polycarbonate plate covered with the photosensitive dye layer in an ethanol aqueous solution (ethanol: water = 1:1, v / v), take out and wipe off the dye in the photosensitive dye layer with a dust-free paper to obtain a transparent DVD disc polycarbonate plate; apply a mixture containing polydimethylsiloxane (PDMS and Dow Corning Sylgard184 curing agent, mass ratio 1:1) on the surface of the DVD disc polycarbonate plate, place it on a heating table at 60°C for 2 hours to cure, and obtain a PDMS film with a replica of the disc channel array, which is cut into a size of 1 cm×1 cm;

[0073] S2, the silicon wafer (surface has SiO 2 The substrate was cut into 1 cm × 1 cm size with acetone, 95% ethanol, and deionized water for ultrasonic cleaning in sequence, with an ultrasonic power of 135 W and a time of 10 min each time, and then the substrate was blown dry with nitrogen to remove residual moisture and stains;

[0074] S3, put the cleaned silicon wafer into a plasma cleaning machine for 300 seconds, further remove surface impurities and introduce polar groups such as hydroxyl (-OH) on the substrate surface to make the surface hydrophilic, then take 10mL of n-hexane and 10μL of OTS solution to prepare a mixed solution, put the silicon wafer into the solution and seal it for 2 hours to achieve surface hydrophobic treatment; after the hydrophobic treatment is completed, quickly remove the residual solution on the surface with acetone, and blow dry with nitrogen to obtain a hydrophobic silicon wafer substrate;

[0075] S4, mix CsBr and PbBr in a 1:1 ratio 2 Put it into the reagent bottle containing DMSO solution to make a 0.2 mol / L concentration of CsPbBr 3 solution, and then weigh 5% CsPbBr 3 Add solution-quality PVP powder into the solution and mix it. After sealing, stir the solution with a stirring bar to fully dissolve it.

[0076] S5. Place the hydrophobic silicon wafer substrate on the heating table and take 10uL CsPbBr 3 The mixed solution with PVP was added dropwise onto the hydrophobic silicon wafer with SiO 2The PDMS film obtained in step S1 is quickly covered on the hydrophobic silicon substrate, with the side with the replica channel facing the substrate, and the PDMS film is gently pressed to make it fit with the hydrophobic silicon substrate. The heating temperature of the heating stage is set to 75°C and the heating time is 4h. After the heating is completed, the PDMS film is gently lifted to obtain a horizontally oriented CsPbBr 3 Nanowire arrays.

[0077] Comparative Example 1

[0078] This comparative example prepares a horizontally oriented CsPbBr 3 The nanowire array, which differs from Example 1 in that no PVP surfactant is used, is prepared as follows:

[0079] S1. Tear off the protective layer of the DVD disc to obtain a polycarbonate plate covered with a metal reflective layer and a photosensitive dye layer, peel off the metal reflective layer with tape to obtain a polycarbonate plate covered with a photosensitive dye layer, immerse the polycarbonate plate covered with the photosensitive dye layer in an ethanol aqueous solution (ethanol: water = 1:1, v / v), take out and wipe off the dye in the photosensitive dye layer with a dust-free paper to obtain a transparent DVD disc polycarbonate plate; apply a mixture containing polydimethylsiloxane (PDMS and Dow Corning Sylgard184 curing agent, mass ratio 1:1) on the surface of the DVD disc polycarbonate plate, place it on a heating table at 60°C for 2 hours to cure, and obtain a PDMS film with a replica of the disc channel array, which is cut into a size of 1 cm×1 cm;

[0080] S2. Cut the glass slide into 1 cm × 1 cm size, and clean it with acetone, 95% ethanol, and deionized water in sequence, with an ultrasonic power of 135 W and a time of 10 min each time, and then blow dry the substrate with nitrogen to remove residual moisture and stains;

[0081] S3, put the cleaned glass into a plasma cleaning machine for 300 seconds, further remove surface impurities and introduce polar groups such as hydroxyl (-OH) on the substrate surface to make the surface hydrophilic, then take 10mL of n-hexane and 10μL of OTS solution to prepare a mixed solution, put the glass substrate into the solution and seal it for 2 hours to achieve surface hydrophobic treatment; after the hydrophobic treatment is completed, quickly remove the residual solution on the surface with acetone, and blow dry with nitrogen to obtain a hydrophobic glass substrate;

[0082] S4, mix CsBr and PbBr in a 1:1 ratio 2 Put it into the reagent bottle containing DMSO solution to make a 0.2 mol / L concentration of CsPbBr 3 Solution;

[0083] S5. Place the hydrophobic glass substrate on the heating table and take 10uL CsPbBr 3 The solution was dripped onto the hydrophobic glass substrate, and then the PDMS film obtained in step S1 was quickly covered on the hydrophobic glass substrate, with the side with the replica channel facing the substrate, and the PDMS film was gently pressed to make it fit with the hydrophobic glass substrate. The heating temperature of the heating table was set to 75 ° C, and the heating time was 4 h. After the heating was completed, the PDMS film was gently lifted to obtain the horizontally oriented CsPbBr 3 Nanowire arrays.

[0084] Comparative Example 2

[0085] This comparative example prepares a horizontally oriented CsPbBr 3 The nanowire array is different from Example 2 in that the silicon wafer substrate is not subjected to hydrophobic treatment, and the preparation steps are as follows:

[0086] S1. Tear off the protective layer of the DVD disc to obtain a polycarbonate plate covered with a metal reflective layer and a photosensitive dye layer, peel off the metal reflective layer with tape to obtain a polycarbonate plate covered with a photosensitive dye layer, immerse the polycarbonate plate covered with the photosensitive dye layer in an ethanol aqueous solution (ethanol: water = 1:1, v / v), take out and wipe off the dye in the photosensitive dye layer with a dust-free paper to obtain a transparent DVD disc polycarbonate plate; apply a mixture containing polydimethylsiloxane (PDMS and Dow Corning Sylgard184 curing agent, mass ratio 1:1) on the surface of the DVD disc polycarbonate plate, place it on a heating table at 60°C for 2 hours to cure, and obtain a PDMS film with a replica of the disc channel array, which is cut into a size of 1 cm×1 cm;

[0087] S2. Cut the silicon wafer into 1 cm × 1 cm size, and perform ultrasonic cleaning with acetone, 95% ethanol, and deionized water in sequence, with an ultrasonic power of 135 W and a time of 10 min each time, and then blow dry the substrate with nitrogen to remove residual moisture and stains;

[0088] S3, placing the cleaned silicon wafer in a plasma cleaning machine for cleaning for 300 seconds, further removing surface impurities and introducing polar groups such as hydroxyl groups (-OH) on the substrate surface to convert the surface into a hydrophilic state, thereby obtaining a hydrophilic silicon wafer substrate;

[0089] S4, mix CsBr and PbBr in a 1:1 ratio 2 Put it into the reagent bottle containing DMSO solution to make a 0.2 mol / L concentration of CsPbBr 3 solution, and then weigh 5% CsPbBr 3 Add solution-quality PVP powder into the solution and mix it. After sealing, stir the solution with a stirring bar to fully dissolve it.

[0090] S5. Place the hydrophilic silicon wafer substrate on the heating table and take 10 μL CsPbBr 3 The mixed solution with PVP was dripped onto the surface of the hydrophilic silicon wafer, and then the PDMS film obtained in step S1 was quickly covered on the hydrophilic silicon wafer substrate, with the side with the replica channel facing the substrate, and the PDMS film was gently pressed to make it fit with the hydrophilic silicon wafer substrate. The heating temperature of the heating table was set to 75 ° C, and the heating time was 4 h. After the heating was completed, the PDMS film was gently lifted to obtain the horizontally oriented CsPbBr 3 Nanowire arrays.

[0091] Material Characterization and Performance Testing

[0092] 1. Scanning electron microscope test of the PDMS film with channel array in Example 1:

[0093] Figure 4 is a scanning electron microscope image of the PDMS film with a channel array in Example 1, Figure 4 It can be seen that by scraping the PDMS mixture on the polycarbonate template, the nanoscale channel array on the template can be successfully replicated.

[0094] 2. Substrate hydrophobicity test:

[0095] Figure 5 The water contact angle images of the glass substrate before (a) and after (b) hydrophobic treatment in Example 1 are shown in FIG. Figure 5 It can be seen that the present invention uses a method of hydrophobic modification by immersing in a mixed solution of n-hexane and octadecyltrichlorosilane, and using octadecyltrichlorosilane (OTS) to react with hydroxyl (-OH) to generate polyoctadecylsiloxane (PODS), which effectively reduces the surface energy of the glass slide substrate and effectively increases the contact angle between the solution and the substrate surface, thereby effectively improving the adhesion between the glass substrate and the CsPbBr in the PDMS interlayer. 3 The spatial confinement of the solution allows the solution to be better confined in the channel array of the PDMS replica and grow into nanowires, effectively preventing CsPbBr 3 Diffusion on a glass substrate results in the formation of square boules.

[0096] 3. Horizontally oriented CsPbBr in Example 1 3 Optical microscopy testing of nanowire arrays:

[0097] Figure 6 The horizontally oriented CsPbBr in Example 1 3 Optical microscope image of the nanowire array magnified 50 times. Figure 7 The horizontally oriented CsPbBr in Example 1 3 Optical microscope image of the nanowire array magnified 100 times. Figure 8The horizontally oriented CsPbBr in Example 1 3 Optical microscope image of the nanowire array magnified 1000 times, by Figure 6 , Figure 7 and Figure 8 It can be seen that the preparation method in Example 1 can simultaneously perform nanowire growth and arrangement assembly to obtain CsPbBr 3 Nanowires, the length of nanowires ranges from a few hundred microns to a few millimeters, and the continuity of nanowires is relatively good, with few disconnections.

[0098] Fig. 9 The horizontally oriented CsPbBr in Example 1 3 Optical microscope image of the nanowire array magnified 5000 times, by Fig. 9 It can be seen that the preparation method in Example 1 can grow CsPbBr 3 Nanowires with high morphology uniformity and good crystal quality.

[0099] 4. Horizontally oriented CsPbBr in Example 2 and Comparative Example 2 3 Optical microscopy testing of nanowire arrays:

[0100] Fig.10 For the horizontally oriented CsPbBr in Example 2 3 Optical microscope image of the nanowire array magnified 50 times. Fig.11 For the horizontally oriented CsPbBr in Comparative Example 2 3 Optical microscope image of the nanowire array magnified 50 times, by Fig.10 and Fig.11 It can be seen that after hydrophobic modification of the silicon wafer substrate, neatly arranged CsPbBr 3 Nanowires, when the silicon wafer substrate is not hydrophobically modified, the solution will penetrate on the substrate and grow into bulk CsPbBr 3 .

[0101] 5. Horizontally oriented CsPbBr in Comparative Example 1 3 Optical microscopy testing of nanowire arrays:

[0102] Fig.12 For the horizontally oriented CsPbBr in Comparative Example 1 3 Optical microscope image of the nanowire array magnified 5000 times, by Fig.12 It can be seen that in Comparative Example 1, since PVP surfactant was not used, CsPbBr 3 The crystal quality of nanowires is relatively poor, and the disconnection phenomenon increases. This indicates that in CsPbBr 3Adding a certain amount of PVP to the solution can control the crystallization direction and morphology of nanowires. PVP can inhibit the growth rate of nanowires by forming a complex with cesium ions, which helps the growth of nanowires to be more uniform and can significantly extend the length of nanowires to the millimeter level. However, too high a PVP content will also have a negative impact on the growth of nanowires, such as reducing the size of nanowires and increasing defects. Therefore, it is necessary to add a certain amount of PVP to the solution. 3 Add an appropriate amount of PVP surfactant into the solution.

[0103] The horizontally guided CsPbBr 3 The preparation method of the nanowire array can use the DVD disc polycarbonate plate as the channel array template, and copy the channel array to the surface of the PDMS film by a simple method; select a flat substrate such as glass or silicon wafer for the growth of nanowires, and after hydrophobic treatment, the contact angle between the solution and the substrate surface can be increased to prevent the solution from penetrating; in CsPbBr 3 Adding PVP surfactant to the solution can better control the growth direction and morphology of the nanowires and improve their crystallinity and uniformity. Compared with the vapor deposition method, the preparation method provided by the present invention does not require a high temperature and low pressure environment. Under the condition of 60-80°C, CsPbBr with neat horizontal arrangement, good continuity and high crystal quality can be obtained within 3-5 hours. 3 Nanowire arrays have low requirements for the preparation environment, short preparation time, and high product quality. They only need to provide sufficient heating area to grow any number of samples, which is conducive to application in large-scale production. Compared with other solution template methods, they can greatly improve the spatial confinement ability of the solution, allowing the material to grow better along the nanoscale channel array in PDMS, effectively preventing the solution from diffusing and growing into a thin film or other crystal blocks on the substrate.

Claims

1. A method for preparing a horizontally guided CsPbBr3 nanowire array, characterized in that: The following steps are involved: S1, applying a mixture containing polydimethylsiloxane to a channel array template by scraping, heating and curing, and peeling off to obtain a polydimethylsiloxane film with a channel array; S2, cleaning the substrate and performing hydrophobic modification to obtain a hydrophobic substrate; S3, taking CsPbBr3 solution, adding surfactant to obtain a mixed solution; S4, dropping the mixed solution onto the surface of the hydrophobic substrate, covering the polydimethylsiloxane film with the channel array, compacting, heating, and peeling off to obtain a horizontally guided CsPbBr3 nanowire array.

2. The preparation method according to claim 1, characterized in that: In the step S1, the channel array template includes one of a DVD disc polycarbonate plate and an M-plane sapphire.

3. The preparation method according to claim 1, characterized in that: In the step S1, the mixture containing polydimethylsiloxane includes polydimethylsiloxane and a curing agent; Preferably, the mass ratio of the polydimethylsiloxane to the curing agent is (8-12):1; Preferably, the curing agent comprises an organosilicon curing agent.

4. The preparation method according to claim 1, characterized in that: In the step S1, the temperature of the heating and curing is 55-65°C; And / or, the heating and curing time is 1.5 to 2.5 hours.

5. The preparation method according to claim 1, characterized in that: In step S2, the substrate includes one of glass, silicon wafer, and sapphire; And / or, the reagent used for cleaning the substrate includes a ketone solvent, an alcohol solvent and water.

6. The preparation method according to claim 1, characterized in that: In the step S2, the hydrophobic modification includes sequentially performing plasma cleaning and soaking in a mixed solution of n-hexane and octadecyltrichlorosilane; Preferably, the plasma cleaning time is 250 to 350 seconds; Preferably, the volume ratio of n-hexane to octadecyltrichlorosilane is (900-1100):1; Preferably, the soaking time is 1.5 to 2.5 hours.

7. The preparation method according to claim 1, characterized in that: In step S3, the concentration of the CsPbBr3 solution is 0.1-0.3 mol / L.

8. The preparation method according to claim 1, characterized in that: In the step S3, the mass ratio of the surfactant to the CsPbBr3 solution is 1:(15-25); Preferably, the surfactant comprises polyvinyl pyrrolidone.

9. The preparation method according to claim 1, characterized in that: In step S4, the heating temperature is 60-80°C; And / or, the heating time is 3 to 5 hours.

10. Use of the horizontally guided CsPbBr3 nanowire array prepared by the preparation method according to any one of claims 1 to 9 in the preparation of optoelectronic devices.

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