Vertically oriented mesoporous silica and perovskite composite film and preparation method and application thereof

Abstract

The invention discloses a vertically-oriented mesoporous silica and perovskite composite film and a preparation method and application thereof, and belongs to the technical field of luminescent materials. According to the composite film prepared by the invention, the perovskite is effectively filled into a highly ordered mesoporous silica film with a vertical channel in a heating evaporation or soaking manner, and the channel is collapsed through high-temperature calcination, so that a structure that the perovskite is wrapped by silica is formed, and effective coating of the perovskite by the mesoporous silica can be realized; the dispersion problem is avoided, and the stability and performance of the perovskite material are remarkably improved. The vertically-oriented mesoporous silica-coated perovskite composite film prepared by the invention has excellent water and heat stability, can amplify spontaneous emission signals, and provides reliable technical support for practical application of a perovskite laser.

Description

Technical Field

[0001] The present application relates to the technical field of luminescent materials, and in particular to a vertically oriented mesoporous silica and perovskite composite film, and a preparation method and application thereof. Background Art

[0002] Perovskite materials have shown great application potential in optoelectronic devices such as solar cells, light-emitting diodes and lasers due to their excellent optoelectronic properties. The photoelectric conversion efficiency of perovskite solar cells has increased rapidly in the past decade and has now exceeded 25%, which is close to that of traditional silicon-based solar cells. In addition, perovskite light-emitting diodes (PeLEDs) have attracted widespread attention in the fields of display and lighting due to their high photoluminescence quantum efficiency, wide color gamut and tunable emission wavelength.

[0003] In terms of laser applications, perovskite materials have become a hot candidate for new laser materials due to their low threshold and high gain characteristics. However, stability and heat dissipation issues are difficult problems that hinder the practical application of perovskite lasers. In order to overcome these difficulties, researchers have proposed a variety of methods, including surface modification, addition of stabilizers, and composite structures. Among them, mesoporous silica is an ideal shell layer due to its extremely low solid ion diffusion rate, high transparency in the visible wavelength range, and adjustable pore size that can adjust the growth of perovskite. In particular, after high-temperature calcination to close the mesopores, the silica-coated perovskite has extremely high water and thermal stability. However, these high-temperature synthesized mesoporous silica-coated perovskite nanospheres have poor dispersibility, making their application in devices challenging.

[0004] In addition, the traditional method usually achieves the filling of perovskite in mesoporous silica by spin coating perovskite on the surface of mesoporous silica film. Since the perovskite precursor solution is usually dissolved in DMSO or DMF with large surface tension, it is difficult to ensure that the perovskite solution enters the pores of mesoporous silica only by spin coating. The coating effect of mesoporous silica on perovskite is quite limited. Therefore, how to achieve effective coating of perovskite with mesoporous silica is also a problem that needs to be solved. Summary of the invention

[0005] Based on this, the main purpose of this application is to provide a vertically oriented mesoporous silica and perovskite composite film. Under heating conditions, the gaseous perovskite precursor can easily enter the vertically oriented mesoporous silica, and after heating, the channel collapses and transforms into mesoporous silica-coated perovskite, achieving high-efficiency photoluminescence performance. The composite film can achieve effective coating of perovskite with mesoporous silica, avoiding the problem of poor dispersion of coated perovskite nanospheres prepared by traditional porous silica methods, and has high environmental stability, can achieve efficient laser output, and has the function of amplifying spontaneous radiation signals, providing reliable technical support for the practical application of perovskite lasers.

[0006] In a first aspect of the present application, a method for preparing a vertically oriented mesoporous silica and perovskite composite film is provided, comprising the following steps:

[0007] Preparation of vertically oriented mesoporous silica films;

[0008] adding a flux to the vertically oriented mesoporous silica film to prepare a mesoporous silica film with the flux added;

[0009] Filling perovskite into the mesopores of the mesoporous silica film with flux added and calcining to seal the mesopores, so as to prepare the vertically oriented mesoporous silica and perovskite composite film;

[0010] The step of filling the perovskite into the mesopores of the mesoporous silica film with flux added thereto and calcining to seal the mesopores comprises:

[0011] Heating a perovskite material source and a mesoporous silica film with a flux at 600-900° C. to evaporate the perovskite and fill it into the mesopores of the mesoporous silica film with the flux, and to seal the mesopores of the silica;

[0012] or immersing the mesoporous silica film with flux in a solution of a perovskite material source, drying, and calcining at 600-900° C.;

[0013] In some embodiments, the perovskite is an all-inorganic halide perovskite; the all-inorganic halide perovskite includes at least one of Cs3Cu2X5, Cs2AgBiX6, Cs3Bi2X9 and CsPbX3; wherein X is selected from at least one of Br, Cl and I;

[0014] And / or the flux includes at least one of potassium carbonate, potassium nitrate, sodium nitrate and potassium bromide.

[0015] In some embodiments, the vertically oriented mesoporous silica film is vertically grown on a substrate; the substrate comprises at least one of glass, quartz, ITO and silicon wafer.

[0016] In some embodiments, in the perovskite material source, the molar ratio of cesium halide to lead halide is 1.2:1-2:1.

[0017] In some embodiments, the step of adding a flux to the vertically oriented mesoporous silica film to prepare the mesoporous silica film with the flux includes:

[0018] The flux is dispersed in water to prepare an aqueous solution of the flux, and the aqueous solution of the flux is attached to the vertically oriented mesoporous silica film by coating or immersion to prepare the mesoporous silica film with the flux.

[0019] In some embodiments, the molar concentration of the aqueous solution of the flux is 0.01-0.5 mol / L.

[0020] In some embodiments, the heating time and the calcining time are each independently selected from 30-60 min.

[0021] In some embodiments, the step of preparing a vertically oriented mesoporous silica film comprises:

[0022] Dissolve hexadecyltrimethylammonium bromide in a third solvent, add ammonia water and a silicon source to prepare a mixed solution, place the substrate in the mixed solution, grow at 50-70° C. for 12-48 hours, remove the hexadecyltrimethylammonium bromide, and prepare the vertically oriented mesoporous silica film.

[0023] The second aspect of the present application provides a vertically oriented mesoporous silica and perovskite composite film prepared by the aforementioned preparation method.

[0024] The third aspect of the present application provides the application of the aforementioned vertically oriented mesoporous silica and perovskite composite film in a laser.

[0025] The fourth aspect of the present application provides a laser comprising the aforementioned vertically oriented mesoporous silica and perovskite composite film.

[0026] Beneficial effects of this application:

[0027] 1. The composite film prepared in the present application effectively fills the perovskite into a highly ordered mesoporous silica film with vertical channels by means of heating evaporation or immersion, and collapses the channels by high-temperature calcination to form a structure in which the perovskite is wrapped by silica, which can achieve effective coating of the perovskite with mesoporous silica, thereby significantly improving the stability and performance of the perovskite material.

[0028] 2. The vertically oriented mesoporous silica-coated perovskite composite film prepared in this application has excellent water and thermal stability, and also has the function of amplifying spontaneous radiation signals, providing reliable technical support for the practical application of perovskite lasers. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art description. The drawings are only used to illustrate the preferred implementation methods and are not considered to be limitations of the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0030] Figure 1 It is a schematic diagram of filling perovskite into the mesopores of the mesoporous silica film with flux added and calcining to close the mesopores.

[0031] Figure 2 Surface morphologies of the vertically oriented mesoporous silica film and the vertically oriented mesoporous silica and perovskite composite film prepared in Example 1.

[0032] Figure 3 This is a photoluminescence spectrum of the vertically oriented mesoporous silica and perovskite composite film prepared in Example 1 before and after being immersed in water for 12 hours.

[0033] Figure 4 The thermal stability of the vertically oriented mesoporous silica and perovskite composite film (CsPbBr3-MSNCs) prepared in Example 1 and the quasi-two-dimensional perovskite polycrystalline film (CsPbBr3-Film) prepared in Comparative Example 1.

[0034] Figure 5 This is a comparison graph of the fluorescence spectra (PL) under optical pumping of the vertically oriented mesoporous silica and perovskite composite film (CsPbBr3-MSNCs) prepared in Example 1, the polycrystalline film (CsPbBr3-Film) of quasi-two-dimensional perovskite prepared in Comparative Example 1, and the spherical mesoporous silica-coated perovskite (CsPbBr3-MS sphere) prepared in Comparative Example 2. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of this application clearer and to provide a more thorough and comprehensive understanding of the disclosed content of this application, the technical solution of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. The described embodiments are only part of the embodiments of this application, not all of them.

[0036] The implementation of the present application is described in detail below in conjunction with the accompanying drawings. This embodiment is implemented based on the technical solution of the present application, and a detailed implementation method and specific operation process are given, but the protection scope of the present application is not limited to the following embodiments.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0038] the term

[0039] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0040] In the present application, "plurality", "multiple" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" or "at least one" means one or greater than or equal to two.

[0041] In the present application, the terms "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0042] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0043] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0044] In the present application, the term "room temperature" generally refers to 4-35° C., preferably 20±5° C. In the embodiments of the present application, room temperature refers to 20-30° C.

[0045] In this application, unless otherwise specified, the temperature parameter is allowed to be either a constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C and ±1°C are allowed.

[0046] In this application, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 2-5h means that the units of the left endpoint "2" and the right endpoint "5" are both h (hours).

[0047] In a first aspect of the present application, a method for preparing a vertically oriented mesoporous silica and perovskite composite film is provided, comprising the following steps:

[0048] Preparation of vertically oriented mesoporous silica films;

[0049] adding a flux to the vertically oriented mesoporous silica film to prepare a mesoporous silica film with the flux added;

[0050] Filling perovskite into the mesopores of the mesoporous silica film with flux added and calcining to seal the mesopores, so as to prepare the vertically oriented mesoporous silica and perovskite composite film;

[0051] The step of filling the perovskite into the mesopores of the mesoporous silica film with flux added thereto and calcining to seal the mesopores comprises:

[0052] Heating a perovskite material source and a mesoporous silica film with a flux at 600-900° C. to evaporate the perovskite and fill it into the mesopores of the mesoporous silica film with the flux, and to seal the mesopores of the silica;

[0053] Alternatively, the mesoporous silica film with flux added is immersed in a solution of a perovskite material source, dried, and calcined at 600-900°C.

[0054] The composite film prepared in this application effectively fills the perovskite into a highly ordered mesoporous silica film with vertical channels by heating evaporation or immersion, and collapses the channels by high-temperature calcination to form a structure in which the perovskite is wrapped by silica, which can achieve effective coating of the perovskite by mesoporous silica, avoid dispersion problems, and significantly improve the stability and performance of the perovskite material. The vertically oriented mesoporous silica-coated perovskite composite film prepared in this application has excellent water and thermal stability, and also has an amplified spontaneous emission signal (ASE), providing reliable technical support for the practical application of perovskite lasers.

[0055] The inventors found that it is difficult to amplify spontaneous emission with ordinary mesoporous silica (such as SBA-15). The reason may be that ordinary mesoporous silica has no orientation and it is difficult to amplify optical signals, which directly affects the generation of ASE because ASE is a process based on the amplification of spontaneous radiation.

[0056] The vertically oriented mesoporous silica and perovskite composite film prepared in the present application has an amplified spontaneous emission signal, which may be the result of the combined effect of the following factors: 1) The vertical mesoporous structure provides a strong waveguide effect for the perovskite quantum dots, which helps to locally confine and transmit light, thereby enhancing the interaction between light and materials, which is very important for the realization of ASE; 2) The vertically structured mesoporous silica can evenly disperse the perovskite quantum dots, which helps to suppress the reabsorption loss that may be caused by the aggregation of quantum dots, and improves the overall light conversion efficiency of the perovskite quantum dots; 3) In the step of filling the perovskite into the mesopores of the mesoporous silica film with the flux and calcining to close the mesopores, high-temperature evaporation or high-temperature calcination after immersion is used to ensure that the perovskite effectively enters the mesoporous silica, and the high-temperature calcination causes the channel to collapse, forming a structure in which the perovskite is wrapped by silica, which can improve the stability and light conversion efficiency of the titanite quantum dots.

[0057] In some embodiments, the perovskite is an all-inorganic halide perovskite; optionally, the all-inorganic halide perovskite includes at least one of Cs3Cu2X5, Cs2AgBiX6, Cs3Bi2X9 and CsPbX3; wherein X is selected from at least one of Br, Cl and I.

[0058] It is understandable that the role of the flux is to reduce the calcination temperature, and the present application does not specifically limit the specific type of the flux. In some embodiments, the flux includes at least one of potassium carbonate, potassium nitrate, sodium nitrate and potassium bromide.

[0059] In some embodiments, the vertically oriented mesoporous silica film is vertically grown on a substrate; the substrate comprises at least one of glass, quartz, ITO and silicon wafer.

[0060] In some embodiments, in the perovskite material source, the molar ratio of cesium halide to lead halide is 1.2:1-2:1, specifically 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, etc.

[0061] It is understandable that the perovskite material source includes perovskite powder and / or polycrystalline perovskite film; the solution of the perovskite material source is a perovskite precursor solution.

[0062] Specifically, the polycrystalline perovskite film preparation step includes: dissolving cesium halide and lead halide in a first solvent to prepare a first perovskite precursor solution, and then coating to prepare a polycrystalline perovskite film;

[0063] The perovskite precursor solution preparation process comprises: dissolving cesium bromide and lead halide in a second solvent to prepare a second perovskite precursor solution.

[0064] It is understandable that in the process of preparing the polycrystalline perovskite film, the coating can be performed by spin coating, spray coating, etc.; wherein the spin coating process can be performed at 500-2000 rpm for 30-90 seconds.

[0065] It is understandable that the first solvent and the second solvent each independently include dimethyl sulfoxide and / or N,N-dimethylformamide. The first solvent and the second solvent may be a single solvent or a composite solvent.

[0066] It can be understood that in the first perovskite precursor solution, the molar concentration of cesium halide is 0.01-0.2 mol / L, specifically 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.10 mol / L, 0.12 mol / L, 0.14 mol / L, 0.16 mol / L, 0.17 mol / L, 0.18 mol / L, 0.19 mol / L, 0.20 mol / L, 0.21 mol / L, 0.22 mol / L, 0.23 mol / L, 0.24 mol / L, 0.25 mol / L, 0.26 mol / L, 0.27 mol / L, 0.28 mol / L, 0.29 mol / L, 0.30 mol / L, 0.31 mol / L, 0.32 mol / L, 0.33 mol / L, 0.34 mol / L, 0.35 mol / L, 0.36 mol / L, 0.37 mol / L, 0.38 mol / L, 0.39 mol / L, 0.40 mol / L, 0.41 mol / L, 0.42 mol / L, 0.43 mol / L, 0.44 mol / L, 0.45 mol / L, 0.46 mol / L, 0.47 mol / L, 0.48 mol / L, 0.49 mol / L, 0.50 6mol / L, 0.18mol / L, 0.20mol / L, etc.; in the second perovskite precursor solution, the molar concentration of cesium halide is 0.01-0.1mol / L, specifically 0.01mol / L, 0.02mol / L, 0.03mol / L, 0.04mol / L, 0.05mol / L, 0.06mol / L, 0.07mol / L, 0.08mol / L, 0.09mol / L, 0.10mol / L, etc.

[0067] In some embodiments, the step of adding a flux to the vertically oriented mesoporous silica film to prepare the mesoporous silica film with the flux includes:

[0068] The flux is dispersed in water to prepare an aqueous solution of the flux, and the aqueous solution of the flux is attached to the vertically oriented mesoporous silica film by coating or immersion to prepare the mesoporous silica film with the flux.

[0069] In some embodiments, the molar concentration of the aqueous solution of the flux is 0.01-0.5 mol / L, specifically 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.10 mol / L, 0.20 mol / L, 0.30 mol / L, 0.40 mol / L, 0.50 mol / L, etc.

[0070] In some embodiments, the heating time and the calcination time are each independently selected from 30-60 min, specifically 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0071] In some embodiments, the step of heating the perovskite material source and the mesoporous silica film with flux at 600-900° C. to evaporate the perovskite, fill it into the mesopores of the mesoporous silica film with flux, and seal the mesopores of the silica specifically includes:

[0072] Place the first perovskite material source at the bottom of the crucible, place the mesoporous silica film with flux added 1-4 cm above the first perovskite material source (specifically 1 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, etc.), and heat at 600-900°C (specifically 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, etc.) for 30-60 minutes.

[0073] Understandably, in the above process, heating has a dual role: evaporating the perovskite to form vapor of the perovskite precursor, which fills the mesopores in gaseous form, and collapsing the mesoporous silica channels to form a structure in which the perovskite is encapsulated by silica.

[0074] In some embodiments, the steps of immersing the mesoporous silica film with flux in a solution of a perovskite material source, drying, and calcining at 600-900° C. specifically include:

[0075] The mesoporous silica film added with a flux (molar concentration of 0.01-0.5 mol / L) is immersed in a solution of a perovskite material source, stirred at 40-70°C (specifically 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, etc.) for 6-36h (specifically 6h, 12h, 18h, 24h, 30h, 36h, etc.), and calcined at 600-900°C (specifically 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, etc.) for 30-60min.

[0076] In some embodiments, the step of preparing a vertically oriented mesoporous silica film comprises:

[0077] Dissolve hexadecyltrimethylammonium bromide in a third solvent, add ammonia water and a silicon source to prepare a mixed solution, place the substrate in the mixed solution, grow at 50-70° C. for 12-48 hours, remove the hexadecyltrimethylammonium bromide, and prepare the vertically oriented mesoporous silica film.

[0078] It is understandable that the ratio of raw materials used in the vertically oriented mesoporous silica film can be adjusted according to actual needs and is not particularly limited. Among them, the third solvent can be a mixed solvent of ethanol and water, and the volume ratio of ethanol and water can be 1:1-5; the mass volume ratio of hexadecyltrimethylammonium bromide to the third solvent can be (0.05-0.5) g:100mL; the mass concentration of ammonia water is 15-40wt%; the silicon source can include tetraethoxysilane; the mass volume ratio of hexadecyltrimethylammonium bromide to ammonia water can be (0.05-0.5) g:5μL; the mass volume ratio of hexadecyltrimethylammonium bromide to tetraethoxysilane can be (0.5-5) g:1mL.

[0079] In some embodiments, the step of removing cetyltrimethylammonium bromide comprises at least one of the following:

[0080] 1) Calcination at 500℃-600℃ for 3-8h;

[0081] 2) After aging at 90-110℃ for 10-30h, soak in 0.05-0.5mol / L hydrochloric acid ethanol solution for 15-360min.

[0082] The second aspect of the present application provides a vertically oriented mesoporous silica and perovskite composite film prepared by the aforementioned preparation method.

[0083] The third aspect of the present application provides the application of the aforementioned vertically oriented mesoporous silica and perovskite composite film in a laser.

[0084] The fourth aspect of the present application provides a laser comprising the aforementioned vertically oriented mesoporous silica and perovskite composite film.

[0085] Unless otherwise specified, the raw materials used in the following experiments can be purchased from the market.

[0086] The following are specific embodiments.

[0087] Example 1

[0088] A method for preparing a vertically oriented mesoporous silica and perovskite composite film, the preparation steps are as follows:

[0089] (1) Preparation of vertically oriented mesoporous silica film: 0.08 g of hexadecyltrimethylammonium bromide (CTAB) was completely dissolved in 15 mL of ethanol and 35 mL of water. Then, 5 µL of concentrated ammonia (25 wt%) and 0.04 mL of tetraethoxysilane (TEOS) were added and stirred for 5 min. Then, a clean substrate (glass) was immersed in the above solution and placed in a constant temperature water bath at 60 °C for 24 h and aged at 100 °C overnight. After that, the sample was immersed in an ethanol solution with a hydrochloric acid concentration of 0.1 mol / L for 30 min to remove CTAB, thereby obtaining a vertically oriented mesoporous silica film.

[0090] (2) Perovskite material source: 0.075mmol lead bromide and 0.05mmol cesium bromide were added to 1mL of DMF and stirred at 60℃ for 2h to obtain a perovskite precursor solution. 100μL of the precursor solution was taken and spin-coated onto a glass slide at 1500rpm for 45s and annealed at 100℃ for 1min to obtain a perovskite polycrystalline film, which was the perovskite material source.

[0091] (3) Adding potassium carbonate to the vertically oriented mesoporous silica film: Dissolve potassium carbonate in deionized water with a molar concentration of 0.03 mol / L, then soak the vertically oriented mesoporous silica film in the potassium carbonate solution for 30 min, and then dry it at 80°C to obtain a mesoporous silica film with potassium carbonate added.

[0092] (4) Filling perovskite into the mesopores of the mesoporous silica film with potassium carbonate and calcining to seal the mesopores: Place the prepared perovskite polycrystalline film at the bottom of the crucible, and place the mesoporous silica film with potassium carbonate 2 cm above the perovskite polycrystalline film. Calcinate at 600°C for 30 min to fill the perovskite polycrystalline film into the mesopores of the mesoporous silica film and seal the mesopores of silica. See the schematic diagram. Figure 1 , a vertically oriented mesoporous silica and perovskite composite film was prepared.

[0093] Example 2

[0094] A method for preparing a vertically oriented mesoporous silica and perovskite composite film, the preparation steps are as follows:

[0095] (1) Preparation of vertically oriented mesoporous silica film: 0.08 g CTAB was completely dissolved in 15 mL ethanol and 35 mL water. Then, 5 µL concentrated ammonia (25 wt%) and 0.04 mL TEOS were added and stirred for 5 min. Then, a clean substrate (glass) was immersed in the above solution and placed in a constant temperature water bath at 60 °C. After growing for 24 h and aging at 100 °C overnight, the sample was immersed in an ethanol solution with a hydrochloric acid concentration of 0.1 mol / L for 30 min to remove CTAB, thereby obtaining a vertically oriented mesoporous silica film.

[0096] (2) Perovskite material source: Place 0.0426 g of lead bromide and 0.1101 g of cesium bromide powder on a clean glass slide as the perovskite material source.

[0097] (3) Adding potassium carbonate to the vertically oriented mesoporous silica film: Dissolve potassium carbonate in deionized water with a molar concentration of 0.3 mol / L, then soak the vertically oriented mesoporous silica film in the potassium carbonate solution for 30 min and dry it at 80°C to obtain a mesoporous silica film with potassium carbonate added.

[0098] (4) Preparation of filling perovskite into the mesopores of a mesoporous silica film with potassium carbonate and calcining to seal the mesopores: The perovskite material source is placed at the bottom of the crucible, and the mesoporous silica film with potassium carbonate is placed 2 cm above the perovskite material source. The film is calcined at 600°C for 30 min to fill the perovskite polycrystalline film into the mesopores and seal the mesopores of silica, thereby preparing a vertically oriented mesoporous silica and perovskite composite film.

[0099] Example 3

[0100] A method for preparing a vertically oriented mesoporous silica and perovskite composite film, the preparation steps are as follows:

[0101] (1) Preparation of vertically oriented mesoporous silica film: 0.08 g CTAB was completely dissolved in 15 mL ethanol and 35 mL water. Then, 5 µL concentrated ammonia (25 wt%) and 0.04 mL TEOS were added and stirred for 5 min. Then, a clean substrate (glass) was immersed in the above solution and placed in a constant temperature water bath at 60 °C. After growing for 24 h and aging at 100 °C overnight, the sample was calcined at 550 °C for 5 h to remove CTAB, thereby obtaining a vertically oriented mesoporous silica film.

[0102] (2) Perovskite material source: Add 0.2202 g of lead bromide and 0.0851 g of cesium bromide into 10 mL of DMSO and stir at 60 °C for 2 h to obtain a perovskite precursor solution, which is the perovskite material source.

[0103] (3) Adding potassium carbonate to the vertically oriented mesoporous silica film: Dissolve potassium carbonate in deionized water with a molar concentration of 0.3 mol / L, then soak the vertically oriented mesoporous silica film in the potassium carbonate solution for 30 min and dry it at 80°C to obtain a mesoporous silica film with potassium carbonate added.

[0104] (4) Preparation of filling perovskite into the mesopores of a mesoporous silica film with potassium carbonate and calcining to seal the mesopores: The mesoporous silica film (1 cm × 1 cm) with potassium carbonate added in (3) was immersed in a perovskite precursor solution, stirred at 60°C for 6 h and then dried. It was then calcined at 600°C for 30 min to fill the perovskite into the mesopores and seal the mesopores of silica, thereby preparing a vertically oriented mesoporous silica and perovskite composite film.

[0105] Example 4

[0106] A method for preparing a vertically oriented mesoporous silica and perovskite composite film, the preparation steps are as follows:

[0107] (1) Preparation of vertical mesoporous silica film: 0.08 g CTAB was completely dissolved in 15 mL ethanol and 35 mL water. Then, 5 µL concentrated ammonia (25 wt%) and 0.04 mL TEOS were added and stirred for 5 min. Then, a clean substrate (glass) was immersed in the above solution and placed in a constant temperature water bath at 60 °C. After growing for 24 h and aging at 100 °C overnight, the sample was immersed in an ethanol solution with a hydrochloric acid concentration of 0.1 mol / L for 30 min to remove CTAB, thereby obtaining a vertically oriented mesoporous silica film.

[0108] (2) Perovskite material source: 0.015mmol lead bromide and 0.01mmol cesium bromide were added to 1mL of DMF and stirred at 60℃ for 2h to obtain a perovskite precursor solution. 100μL of the precursor solution was taken and spin-coated on a glass slide at 1500rpm for 45s and annealed at 100℃ for 1min to obtain a perovskite polycrystalline film, which was the perovskite material source.

[0109] (3) Adding flux to the vertically oriented mesoporous silica film: Dissolve 0.05 mmol potassium bromide and 0.15 mmol sodium nitrate in 1 mL deionized water, then drop the prepared flux solution onto the vertically oriented mesoporous silica film, spin coat at 4000 rpm for 50 s, and dry at 80 °C to obtain a mesoporous silica film with flux added.

[0110] (4) Preparation of filling perovskite into the mesopores of a mesoporous silica film with a flux and calcining to seal the mesopores: Place the prepared perovskite polycrystalline film at the bottom of a crucible, and place the mesoporous silica film with a flux 2 cm above the perovskite polycrystalline film. Calcine at 600°C for 30 min to fill the perovskite polycrystalline film into the mesopores and seal the mesopores of silica, thereby preparing a vertically oriented mesoporous silica and perovskite composite film.

[0111] Comparative Example 1

[0112] Preparation of quasi-two-dimensional perovskite polycrystalline film (CsPbBr3-Film): 0.2 mmol PbBr2, 0.2 mmol CsBr, and 0.08 mmol phenethylammonium bromide were added to 1 mL of DMSO containing crown ether (3.5 mg / mL), and stirred at 60°C for 2 hours to obtain a quasi-two-dimensional perovskite precursor solution. The perovskite precursor solution was spin-coated at 4000 rpm for 50 seconds and then annealed at 100°C for 1 minute to obtain a quasi-two-dimensional perovskite polycrystalline film.

[0113] Comparative Example 2

[0114] Preparation of spherical mesoporous silica-coated perovskite (CsPbBr3-MS sphere):

[0115] Equimolar amounts of CsBr and PbBr2 were dispersed in 50 mL of ultrapure water and stirred continuously at 80°C to completely dissolve CsBr and PbBr2 to form a clear solution. Then, an MCM-41 molecular sieve template 3 times the mass of the perovskite precursor was added and stirred continuously for 1 hour to mix the molecular sieve template and the perovskite precursor evenly, and then the moisture was removed in an oven at 80°C to obtain a solid powder.

[0116] The solid powder was evenly spread on a corundum crucible and placed in a muffle furnace. In an air atmosphere, the temperature was raised from room temperature to 700°C at a rate of 5°C / min and kept constant for 30 min, and then naturally cooled to room temperature. The sample after the above reaction was fully ground and then dispersed in 50 mL of water to wash away the unencapsulated perovskite nanocrystals on the surface of the molecular sieve, and centrifuged at 10,000 rpm for 1 min. The washing process was repeated three times, and then the precipitate after centrifugation was placed in a 60°C constant temperature drying oven and dried for 6 hours to obtain spherical mesoporous silica-coated perovskite (CsPbBr3-MS sphere).

[0117] Test Case

[0118] The surface morphologies of the vertically oriented mesoporous silica film prepared in step (1) of Example 1 and the vertically oriented mesoporous silica and perovskite composite film prepared in step (4) were observed by scanning electron microscopy (Carl Zeiss Supra 55). The results are shown in Table 1. Figure 2 a and b in the figure. The thickness of the film in a is about 50nm, and the pore size distribution is concentrated around 4nm, indicating the uniformity of the film. No pore structure is observed in b, indicating that the mesoporous pores of the composite film have been effectively filled with perovskite materials.

[0119] The photoluminescence spectra of the vertically oriented mesoporous silica and perovskite composite film prepared in Example 1 before and after being immersed in water for 12 hours are shown in FIG. Figure 3 The composite film of Example 1 was immersed in a beaker filled with water. After immersion in water for 12 h, no PL reduction was observed, indicating that the composite film of Example 1 had excellent water stability, further confirming that the perovskite material had been successfully sealed by mesoporous silica.

[0120] The samples were placed on a heating platform at different temperatures for 5 minutes and then tested for thermal stability. The thermal stability results of the vertically oriented mesoporous silica and perovskite composite film (CsPbBr3-MS NCs) prepared in Example 1 and the quasi-two-dimensional perovskite polycrystalline film (CsPbBr3-Film) prepared in Comparative Example 1 are shown in Figure 4 It can be seen that the composite film of Example 1 can still maintain 74% of the luminous intensity at 100°C and 36% of the luminous intensity at 200°C. However, when the exposed quasi-two-dimensional perovskite polycrystalline film (CsPbBr3 Film) is completely quenched at 150°C, the PL intensity at the same temperature is much lower. The thermal stability of the perovskite polycrystalline film prepared in step (2) of Example 1 is inferior to that of the quasi-two-dimensional perovskite polycrystalline film prepared in Comparative Example 1. It can be seen that the thermal stability of the perovskite is greatly improved by compounding with vertically oriented mesoporous silica.

[0121] The fluorescence spectra (PL) of the vertically oriented mesoporous silica and perovskite composite film (CsPbBr3-MS NCs) prepared in Example 1, the polycrystalline film (CsPbBr3-Film) of the quasi-two-dimensional perovskite prepared in Comparative Example 1, and the spherical mesoporous silica-coated perovskite (CsPbBr3-MS sphere) prepared in Comparative Example 2 under optical pumping are compared as shown in FIG. Figure 5 It can be seen that CsPbBr3-Film has a broad spontaneous emission peak with the center at 517nm, and CsPbBr3-MS sphere has a peak at 502nm, that is, there is no amplified spontaneous emission signal in Comparative Examples 1-2. CsPbBr3-MS has peaks at 521nm and 532nm, respectively. The peak at 532nm quickly dominates the emission spectrum and narrows sharply, marking the transition from the spontaneous emission process to the amplified spontaneous emission state, and the half-peak width narrows to about 5.62nm.

[0122] It can be seen that Example 1 composites perovskite with vertically oriented mesoporous silica through a specific process, giving it the characteristic of amplifying spontaneous radiation, and providing reliable technical support for the practical application of perovskite lasers.

[0123] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0124] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for preparing a vertically oriented mesoporous silica and perovskite composite film, characterized in that: The steps include: Preparation of vertically oriented mesoporous silica films; adding a flux to the vertically oriented mesoporous silica film to prepare a mesoporous silica film with the flux added; Filling perovskite into the mesopores of the mesoporous silica film with flux added and calcining to seal the mesopores, so as to prepare the vertically oriented mesoporous silica and perovskite composite film; The step of filling the perovskite into the mesopores of the mesoporous silica film with flux added thereto and calcining to seal the mesopores comprises: Heating a perovskite material source and a mesoporous silica film with a flux at 600-900° C. to evaporate the perovskite and fill it into the mesopores of the mesoporous silica film with the flux, and to seal the mesopores of the silica; Alternatively, the mesoporous silica film with flux added is immersed in a solution of a perovskite material source, dried, and calcined at 600-900°C.

2. The preparation method according to claim 1, characterized in that The flux comprises at least one of potassium carbonate, potassium nitrate, sodium nitrate and potassium bromide; and / or the perovskite is an all-inorganic halide perovskite; Optionally, the all-inorganic halide perovskite includes at least one of Cs3Cu2X5, Cs2AgBiX6, Cs3Bi2X9 and CsPbX3; wherein X is selected from at least one of Br, Cl and I.

3. The preparation method according to claim 1, characterized in that: The vertically oriented mesoporous silicon dioxide film is vertically grown on a substrate; the substrate comprises at least one of glass, quartz, ITO and silicon wafer.

4. The preparation method according to any one of claims 1 to 3, characterized in that: In the perovskite material source, the molar ratio of cesium halide to lead halide is 1.2:1-2:

1.

5. The preparation method according to any one of claims 1 to 3, characterized in that: The step of adding a flux to the vertically oriented mesoporous silica film to prepare the mesoporous silica film with the flux added comprises: The flux is dispersed in water to prepare an aqueous solution of the flux, and the aqueous solution of the flux is attached to the vertically oriented mesoporous silica film by coating or immersion to prepare the mesoporous silica film with the flux.

6. The preparation method according to claim 5, characterized in that: The molar concentration of the aqueous solution of the flux is 0.01-0.5 mol / L.

7. The preparation method according to any one of claims 1 to 3, characterized in that: The heating time and the calcining time are each independently selected from 30-60 minutes.

8. The preparation method according to any one of claims 1 to 3, characterized in that: The steps of preparing a vertically oriented mesoporous silica film include: Dissolve hexadecyltrimethylammonium bromide in a third solvent, add ammonia water and a silicon source to prepare a mixed solution, place the substrate in the mixed solution, grow at 50-70° C. for 12-48 hours, remove the hexadecyltrimethylammonium bromide, and prepare the vertically oriented mesoporous silica film.

9. A vertically oriented mesoporous silica and perovskite composite film prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the vertically oriented mesoporous silica and perovskite composite film prepared by the preparation method according to any one of claims 1 to 8, and the vertically oriented mesoporous silica and perovskite composite film according to claim 9 in lasers.

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