A green light perovskite laser and a preparation method thereof

Abstract

The present application relates to a kind of green light perovskite laser and its preparation method, solve the problem that the energy transfer efficiency of the existing quasi-two-dimensional perovskite is not conducive to the regulation of mixed phase component due to rapid crystallization.The laser includes substrate and the bottom distributed bragg reflector of the alternating structure of titanium oxide and silicon dioxide arranged on substrate in turn, the perovskite luminescent layer of atmosphere auxiliary crystallization created by DMSO and the top distributed bragg reflector of the alternating structure of zinc sulfide and yttrium fluoride.The present application delays the crystallization process of quasi-two-dimensional perovskite by DMSO atmosphere, effectively improves the crystal quality of perovskite, regulates the phase distribution of quasi-two-dimensional perovskite, speeds up the energy transfer process from small n phase (n=2) to large n phase (n≥5), and prepares perovskite film with low surface roughness and good crystallinity. By combining distributed bragg reflector, a microcavity laser is realized under room temperature continuous laser pumping.

Description

Technical Field

[0001] This invention relates to the field of laser technology, specifically to a green perovskite laser and its fabrication method. Background Technology

[0002] Semiconductor lasers possess superior properties such as small size, long lifespan, and high efficiency. Since their discovery in the 1960s, semiconductor lasers have driven the development of various industries, finding wide application in fields such as laser communication, optical storage, and laser marking. Traditional semiconductor lasers typically use inorganic semiconductor materials as the gain medium, relying on epitaxial growth technology, resulting in high manufacturing costs and relatively complex processes. Considering future applications in the Internet of Things, photonics integration, and communications, there is an urgent need for a low-cost, simple-to-process gain medium material.

[0003] Perovskite is a novel semiconductor material that can be prepared by solution method and has great potential for realizing low-cost lasers. Metal halide perovskite materials have the characteristics of high fluorescence quantum efficiency, high light absorption coefficient, tunable wavelength, long carrier diffusion length, and low processing cost, and have attracted much attention in the field of optoelectronic devices. To date, the external quantum efficiency of perovskite light-emitting diodes has exceeded 20% (Nature 2018, 562, 245; Nature 2018, 591, 72; Nat. Photonics 2018, 12, 783). Due to the many excellent optical properties of perovskite materials, they have great potential as laser gain materials. As early as 2014, Guicuan Xing et al. of Nanyang Technological University prepared three-dimensional organic-inorganic hybrid perovskite thin films by solution method and successfully observed the amplified spontaneous emission (ASE) phenomenon at room temperature (Nature Materials. 2014, 13(5): 476-480). Compared to three-dimensional materials, quasi-two-dimensional perovskites introduce large hydrophobic organic cations into the composition of three-dimensional materials, increasing the moisture resistance of perovskite materials and passivating defects to a certain extent. This greatly improves the environmental and operational stability of perovskite materials. The spontaneous formation of quantum well structures within quasi-two-dimensional perovskites enables rapid energy transfer from the low-n phase to the high-n phase, which is beneficial for realizing the ASE phenomenon and low-threshold optically pumped perovskite lasers.

[0004] Solution processing remains a common method for preparing perovskite thin films. However, rapid solvent removal can cause perovskite crystals to leave pores on the surface and lead halides to precipitate. Controlling long-chain / short-chain organic cations, selecting precursor solutions, surface modification, additives, substrates, and recrystallization are all used to regulate perovskite crystal quality. However, most of these processes require introducing other ions into the perovskite precursor solution or at the substrate interface to induce crystallization, or reprocessing the already crystallized film. Solvent recrystallization, in particular, can take anywhere from one hour to two weeks. The relationship between solvent atmosphere and crystallization is generally overlooked. Perovskite crystallization typically begins due to solvent evaporation, leading to supersaturation of the precursor solution. The partial pressure of solvent vapor in the atmosphere largely determines the solvent evaporation rate, significantly affecting the duration and supersaturation of the wet film stage during solution processing. The solvent vapor atmosphere significantly influences the nucleation and growth of perovskite crystals. For quasi-two-dimensional perovskites, rapid crystallization is not conducive to the regulation of mixed phase composition and affects energy transfer efficiency. Summary of the Invention

[0005] This invention addresses the technical problem in existing quasi-two-dimensional perovskites where rapid crystallization hinders the control of mixed-phase composition, thus affecting energy transfer efficiency. It provides a green perovskite laser and its fabrication method. The invention utilizes a simple method to create a solvent atmosphere within a sealed spin coater. 200-1000 μL of dimethyl sulfoxide (DMSO) solution is uniformly sprayed onto the inner wall of the spin coater to slow the crystallization process. This allows for reasonable control of the crystallization rate, resulting in a perovskite thin film with a smooth surface, few pinholes, high crystallinity, and high energy transfer efficiency. By combining the thin film with a distributed Bragg mirror, a green perovskite laser continuously pumped at room temperature is achieved.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] A green perovskite laser includes a substrate, and a bottom distributed Bragg mirror, a perovskite light-emitting layer and a top distributed Bragg mirror sequentially disposed on the substrate.

[0008] Its features are,

[0009] The bottom distributed Bragg mirror is composed of alternating high-refractive-index titanium dioxide and low-refractive-index silicon dioxide.

[0010] The perovskite luminescent layer is a quasi-two-dimensional perovskite component crystallized with the aid of an atmosphere created by dimethyl sulfoxide (DMSO).

[0011] The top distributed Bragg reflector is an alternating structure of high-refractive-index zinc sulfide and low-refractive-index yttrium fluoride.

[0012] In the above technical solution, preferably, the molecular formula of the quasi-two-dimensional perovskite component is PEA2FA. n- 1Pb n Br 3n+1 , where n = 6-9, is a quasi-two-dimensional perovskite formed by mixing three materials: lead bromide with a concentration of 0.4-0.8 mmol, formamidin bromide with a concentration of 0.4-0.8 mmol, and phenylethylamine bromide with a concentration of 0.1-0.3 mmol.

[0013] In the above technical solution, preferably, the thickness of each layer of titanium oxide in the bottom distributed Bragg reflector is 30-70nm, and the thickness of each layer of silicon dioxide is 80-100nm.

[0014] In the above technical solution, the preferred embodiment is that the bottom distributed Bragg reflector has a total of 15.5 sets of alternating structures of high refractive index titanium dioxide and low refractive index silicon dioxide, with a reflectivity of 99.9% and a thickness of 2-3 μm.

[0015] In the above technical solution, preferably, the thickness of each layer of zinc sulfide in the top distributed Bragg reflector is 30-70 nm, and the thickness of each layer of yttrium fluoride is 80-100 nm.

[0016] In the above technical solution, the preferred embodiment is that the top distributed Bragg reflector has a total of 8.5 sets of alternating structures of high-refractive-index zinc sulfide and low-refractive-index yttrium fluoride, with a reflectivity of 99% and a thickness of 1-2 μm.

[0017] A method for fabricating a green perovskite laser includes the following steps:

[0018] S1. A bottom distributed Bragg reflector is fabricated on a substrate (1);

[0019] S2. Create a dimethyl sulfoxide (DMSO) atmosphere in a closed spin coater;

[0020] S3. A perovskite light-emitting layer is grown on the bottom distributed Bragg mirror;

[0021] S4. A top distributed Bragg reflector is deposited on the perovskite light-emitting layer by vapor deposition;

[0022] During the growth of the perovskite emitting layer, the dimethyl sulfoxide (DMSO) atmosphere slowed down the crystallization process of the perovskite and regulated the phase distribution inside the quasi-two-dimensional perovskite, resulting in lower optical loss and faster internal energy transfer of the perovskite film. The combination of the perovskite film and the distributed Bragg mirror enabled a low-threshold laser continuously pumped at room temperature.

[0023] In the above technical solution, preferably, the dimethyl sulfoxide (DMSO) atmosphere in step S2 is created by uniformly spraying 200-1000 μL of dimethyl sulfoxide (DMSO) inside a sealed spin coater.

[0024] In the above technical solution, preferably, the perovskite precursor solution used to grow the perovskite luminescent layer in step S3 is prepared as follows:

[0025] Using N,N-dimethylformamide (DMF) as solvent, lead bromide (0.4-0.8 mmol), formamidinium bromide (0.4-0.8 mmol), and phenylethylammonium bromide (0.1-0.3 mmol) are mixed to form a quasi-two-dimensional perovskite with the molecular formula PEA2FA. n-1 Pb n Br 3n+1 Where n = 6-9, after thorough stirring at 20℃-80℃, the perovskite precursor solution is formed by filtration through a 0.22μm polytetrafluoroethylene hydrophobic filter membrane.

[0026] In the above technical solution, a further preferred embodiment of the method for fabricating the green perovskite laser of the present invention is as follows:

[0027] Step S1 specifically includes the following steps:

[0028] S11. Place the glass substrate into the ultrasonic cleaner for cleaning, and place the cleaned and wiped glass slide into the sample holder.

[0029] S12. Place the sample holder with the glass substrate into the electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, titanium oxide and silicon dioxide were sequentially deposited onto a glass substrate by evaporation, with 15.5 groups of deposits. The evaporation rate was controlled at 0.35–0.45 nm / s to prepare a bottom distributed Bragg reflector.

[0030] Step S2 specifically includes the following steps:

[0031] S21. 100 μL of perovskite precursor solution is uniformly drop-coated onto the bottom distributed Bragg mirror.

[0032] S22. Spray 200-1000μL of dimethyl sulfoxide (DMSO) solution evenly onto the inner wall of the spin coater, and then turn off the spin coater to maintain a sealed space.

[0033] Step S3 specifically includes the following steps:

[0034] S31. Adjust the spin coating time of the spin coater to 30s, control the spin coating speed to 3000-5000r / min, and drip ether into the top hole at 5-6s after the spin coating starts.

[0035] S32. Place the glass substrate with the spin-coated perovskite precursor solution on a hot stage for annealing to form a perovskite light-emitting layer, and form a quasi-two-dimensional perovskite crystal with high crystallinity, low surface roughness, and rapid energy transfer on the bottom distributed Bragg reflector.

[0036] Step S4 specifically includes the following steps:

[0037] S41. Place the sample holder from step S3 into the electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride were sequentially deposited onto the perovskite emitting layer, with 8.5 deposits. The evaporation rate was controlled at 0.35–0.45 nm / s to prepare a quasi-two-dimensional green perovskite laser with a microcavity structure that can emit green light.

[0038] The principle of this invention is as follows: The green perovskite laser provided by this invention effectively improves the crystal quality of perovskite by delaying the crystallization process of quasi-two-dimensional perovskite in a dimethyl sulfoxide (DMSO) atmosphere, while simultaneously controlling the phase distribution of the quasi-two-dimensional perovskite and accelerating the energy transfer process from the small n-phase (n=2) to the large n-phase (n≥5), thus preparing a perovskite thin film with low surface roughness and good crystallinity. A microcavity laser with continuous laser pumping at room temperature is realized by combining it with a distributed Bragg mirror.

[0039] The beneficial effects of this invention are:

[0040] This invention provides a green perovskite laser and its fabrication method. A dimethyl sulfoxide (DMSO) atmosphere is used to slow down the crystallization rate, influencing the process during crystallization and eliminating the need for subsequent processing time ranging from one hour to two weeks. Through the interaction of the solvent atmosphere with the thin film surface, the crystal quality of the perovskite is effectively improved, while the phase distribution of the quasi-two-dimensional perovskite is controlled, accelerating the energy transfer process and producing a perovskite thin film with low surface roughness and good crystallinity. A high-reflectivity distributed Bragg mirror constructs an effective microcavity, providing stronger gain and enabling a microcavity laser with continuous laser pumping at room temperature. Attached Figure Description

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0042] Figure 1 This is a schematic diagram of the structure of the green perovskite laser of the present invention;

[0043] Figure 2These are the ultraviolet-visible absorption spectra of the perovskite luminescent layer in Comparative Example 1 and Example 1 of the present invention;

[0044] Figure 3 These are the photoluminescence spectra of the perovskite luminescent layer in Comparative Example 1 and Example 1 of the present invention;

[0045] Figure 4 This is a graph showing the fluorescence intensity-pump energy density-full width curve of the perovskite luminescent layer in Comparative Example 1 of this invention.

[0046] Figure 5 This is a graph showing the fluorescence intensity-pump energy density-full width curve of the perovskite luminescent layer in Embodiment 1 of the present invention.

[0047] Figure 6 This is a graph showing the fluorescence intensity-pump energy density-full width curve of the green perovskite laser device under continuous laser pumping in Embodiment 1 of the present invention.

[0048] The reference numerals in the figure are:

[0049] 1-Substrate, 2-Bottom distributed Bragg reflector, 3-Perovskite light-emitting layer, 4-Top distributed Bragg reflector. Detailed Implementation

[0050] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0051] Figure 1 The structure of the green perovskite laser provided by this invention is shown. (See diagram.) Figure 1 As shown, the green perovskite laser of the present invention includes a substrate 1, on which a bottom distributed Bragg reflector 2, a perovskite emitting layer 3, and a top distributed Bragg reflector 4 are sequentially disposed. During the growth of the perovskite emitting layer 3, a dimethyl sulfoxide (DMSO) atmosphere is created to prepare the quasi-two-dimensional green perovskite laser. By delaying the crystallization process of the quasi-two-dimensional perovskite in the DMSO atmosphere, the crystal quality of the perovskite is effectively improved. Simultaneously, the phase distribution of the quasi-two-dimensional perovskite is controlled, accelerating the energy transfer process from the small n-phase (n=2) to the large n-phase (n≥5), thus preparing a perovskite thin film with low surface roughness and good crystallinity.

[0052] The perovskite luminescent layer 3 is a quasi-two-dimensional perovskite component crystallized with the aid of an atmosphere created by dimethyl sulfoxide (DMSO); the molecular formula of the quasi-two-dimensional perovskite component is PEA2FA. n-1 Pb n Br 3n+1, where n = 6-9, is a quasi-two-dimensional perovskite formed by mixing three materials: lead bromide with a concentration of 0.4-0.8 mmol, formamidin bromide with a concentration of 0.4-0.8 mmol, and phenylethylamine bromide with a concentration of 0.1-0.3 mmol.

[0053] The substrate 1 is made of transparent materials such as glass and quartz, and has a thickness of 1-5 mm.

[0054] The bottom distributed Bragg reflector 2 is an alternating structure of high-refractive-index titanium dioxide and low-refractive-index silicon dioxide, with a thickness of 2-3 μm and a reflectivity of 99.9%. There are a total of 15.5 sets of alternating structures, with each layer of titanium dioxide having a thickness of 30-70 nm and each layer of silicon dioxide having a thickness of 80-100 nm.

[0055] The top distributed Bragg reflector 4 is an alternating structure of high-refractive-index zinc sulfide and low-refractive-index yttrium fluoride, with a thickness of 1-2 μm and a reflectivity of 99%. There are a total of 8.5 sets of alternating structures, with each layer of zinc sulfide having a thickness of 30-70 nm and each layer of yttrium fluoride having a thickness of 80-100 nm.

[0056] The method for fabricating a green perovskite laser provided by the present invention includes the following steps:

[0057] S1. Fabricate a bottom distributed Bragg reflector 2 on substrate 1;

[0058] S2. Create a dimethyl sulfoxide (DMSO) atmosphere in a closed spin coater;

[0059] S3. A perovskite light-emitting layer 3 is grown on the bottom distributed Bragg mirror 2;

[0060] S4. A top distributed Bragg reflector 4 is deposited on the perovskite light-emitting layer 3 by vapor deposition.

[0061] During the growth of the perovskite emitting layer 3, the dimethyl sulfoxide (DMSO) atmosphere slowed down the crystallization process of the perovskite and regulated the phase distribution inside the quasi-two-dimensional perovskite, resulting in lower optical loss and faster internal energy transfer of the perovskite film. The combination of the perovskite film and the distributed Bragg mirror realizes a low-threshold laser continuously pumped by laser at room temperature.

[0062] Specifically, one embodiment of the preparation method is as follows:

[0063] Step 1: Place the glass substrate 1 into an ultrasonic cleaner for cleaning, and then place the cleaned and wiped glass substrate 1 into a sample holder. Place the sample holder containing the glass substrate 1 into an electron beam coating machine and perform vacuum treatment until the vacuum level reaches 2×10⁻⁶. - 3At Pa, titanium oxide and silicon dioxide are sequentially deposited onto the glass substrate 1 by evaporation, with 15.5 groups of evaporation. The evaporation rate is controlled at 0.35-0.45 nm / s and the thickness is 2-3 μm, thereby preparing the bottom distributed Bragg reflector 2.

[0064] Step 2: Uniformly drop-coat 100 μL of perovskite precursor solution onto the bottom distributed Bragg reflector 2; uniformly spray 200-1000 μL of dimethyl sulfoxide (DMSO) solution onto the inner wall of the spin coater, and close the spin coater to maintain a sealed space; adjust the spin coater spin coater time to 30 s and control the spin coater speed to 3000-5000 r / min; after starting spin coater spin coater, drop diethyl ether into the top orifice at 5-6 s; place the glass substrate 1 with the perovskite precursor solution spin-coated onto a hot plate for annealing to form a 20-200 nm thick perovskite light-emitting layer 3;

[0065] The preparation method of the above perovskite precursor solution is as follows: N,N-dimethylformamide (DMF) is used as the solvent, the concentration of lead bromide is 0.4-0.8 mmol, the concentration of formamidinium bromide is 0.4-0.8 mmol, and the concentration of phenylethylammonium bromide is 0.1-0.3 mmol, with the molecular formula PEA2FA. n-1 Pb n Br 3n+1 Where n = 6-9, the above three materials are mixed to form a quasi-two-dimensional perovskite. After thorough stirring at 20℃-80℃, the mixture is filtered through a 0.22μm polytetrafluoroethylene hydrophobic filter membrane to form the perovskite precursor solution.

[0066] Step 3: Load the product obtained in Step 2 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride are sequentially deposited onto the perovskite luminescent layer 3, with 8.5 groups of deposited layers. The evaporation rate is controlled at 0.35–0.45 nm / s. A top distributed Bragg reflector 4 with a thickness of 1–2 μm is then deposited.

[0067] Subsequent testing followed. To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0068] Example 1

[0069] The fabrication method of the green perovskite laser provided in Example 1 includes the following steps:

[0070] Step 1: Place the 1mm thick glass substrate 1 into an ultrasonic cleaner for cleaning. After cleaning and wiping, place the cleaned glass substrate 1 into a sample holder. Place the sample holder with the glass substrate 1 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, titanium oxide and silicon dioxide were sequentially deposited onto the glass substrate 1 by evaporation, with 15.5 deposits. The evaporation rate was controlled at 0.4 nm / s. The thickness of each titanium oxide layer was 58.6 nm and the thickness of each silicon dioxide layer was 90.5 nm. In this way, a 2.3 μm bottom distributed Bragg reflector 2 was prepared.

[0071] Step 2: 100 μL of perovskite precursor solution is uniformly drop-coated onto the bottom distributed Bragg reflector 2; 600 μL of dimethyl sulfoxide (DMSO) solution is uniformly sprayed onto the inner wall of the spin coater, and the spin coater is turned off to maintain a sealed space; the spin coater spin coat time is adjusted to 30 s, and the spin coat speed is controlled at 4500 r / min. After the spin coat starts, ether is dropped into the top orifice at 5-6 s; the glass substrate 1 with the perovskite precursor solution spin-coated is placed on a hot plate for annealing at 120°C for 10 minutes to form a 100 nm thick perovskite light-emitting layer 3;

[0072] The preparation method of the above perovskite precursor solution is as follows: N,N-dimethylformamide (DMF) is used as the solvent, the concentration of lead bromide is 0.6 mmol, the concentration of formamidinium bromide is 0.6 mmol, the concentration of phenylethylamine bromide is 0.2 mmol, and the molecular formula is PEA2FA. n-1 Pb n Br 3n+1 (n=6), the above three materials are mixed to form a quasi-two-dimensional perovskite. After thorough stirring at 45°C, the mixture is filtered through a 0.22 μm polytetrafluoroethylene hydrophobic filter membrane to form the perovskite precursor solution.

[0073] Step 3: Load the product obtained in Step 2 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride were sequentially deposited onto the perovskite luminescent layer 3, with 8.5 groups of deposits. The evaporation rate was controlled at 0.4 nm / s. The thickness of each zinc sulfide layer was 58.2 nm, and the thickness of each yttrium fluoride layer was 90.1 nm. A 1.2 μm top distributed Bragg reflector 4 was then deposited.

[0074] Example 2

[0075] The fabrication method of the green perovskite laser provided in Example 2 includes the following steps:

[0076] Step 1: Place the 1mm thick glass substrate 1 into an ultrasonic cleaner for cleaning. After cleaning and wiping, place the cleaned glass substrate 1 into a sample holder. Place the sample holder with the glass substrate 1 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, titanium oxide and silicon dioxide were sequentially deposited onto the glass substrate 1 by evaporation, with 15.5 deposits. The evaporation rate was controlled at 0.4 nm / s. The thickness of each titanium oxide layer was 58.6 nm and the thickness of each silicon dioxide layer was 90.5 nm. In this way, a 2.3 μm bottom distributed Bragg reflector 2 was prepared.

[0077] Step 2: 100 μL of perovskite precursor solution is uniformly drop-coated onto the bottom distributed Bragg reflector 2; 600 μL of dimethyl sulfoxide (DMSO) solution is uniformly sprayed onto the inner wall of the spin coater, and the spin coater is turned off to maintain a sealed space; the spin coater spin coat time is adjusted to 30 s, and the spin coat speed is controlled at 4500 r / min. After the spin coat starts, ether is dropped into the top orifice at 5-6 s; the glass substrate 1 with the perovskite precursor solution spin-coated is placed on a hot plate for annealing at 120°C for 10 minutes to form a 100 nm thick perovskite light-emitting layer 3;

[0078] The preparation method of the above perovskite precursor solution is as follows: N,N-dimethylformamide (DMF) is used as the solvent, the concentration of lead bromide is 0.6 mmol, the concentration of formamidinium bromide is 0.6 mmol, the concentration of phenylethylamine bromide is 0.17 mmol, and the molecular formula is PEA2FA. n-1 Pb n Br 3n+1 (n=7), the above three materials are mixed to form a quasi-two-dimensional perovskite. After thorough stirring at 45°C, the mixture is filtered through a 0.22 μm polytetrafluoroethylene hydrophobic filter membrane to form the perovskite precursor solution.

[0079] Step 3: Load the product obtained in Step 2 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride were sequentially deposited onto the perovskite luminescent layer 3, with 8.5 groups of deposits. The evaporation rate was controlled at 0.4 nm / s. The thickness of each zinc sulfide layer was 58.2 nm, and the thickness of each yttrium fluoride layer was 90.1 nm. A 1.2 μm top distributed Bragg reflector 4 was then deposited.

[0080] Example 3

[0081] The fabrication method of the green perovskite laser provided in Example 3 includes the following steps:

[0082] Step 1: Place the 1mm thick glass substrate 1 into an ultrasonic cleaner for cleaning. After cleaning and wiping, place the cleaned glass substrate 1 into a sample holder. Place the sample holder with the glass substrate 1 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, titanium oxide and silicon dioxide were sequentially deposited onto the glass substrate 1 by evaporation, with 15.5 deposits. The evaporation rate was controlled at 0.4 nm / s. The thickness of each titanium oxide layer was 58.6 nm and the thickness of each silicon dioxide layer was 90.5 nm. In this way, a 2.3 μm bottom distributed Bragg reflector 2 was prepared.

[0083] Step 2: 100 μL of perovskite precursor solution is uniformly drop-coated onto the bottom distributed Bragg reflector 2; 600 μL of dimethyl sulfoxide (DMSO) solution is uniformly sprayed onto the inner wall of the spin coater, and the spin coater is turned off to maintain a sealed space; the spin coater spin coat time is adjusted to 30 s, and the spin coat speed is controlled at 4500 r / min. After the spin coat starts, ether is dropped into the top orifice at 5-6 s; the glass substrate 1 with the perovskite precursor solution spin-coated is placed on a hot plate for annealing at 120°C for 10 minutes to form a 100 nm thick perovskite light-emitting layer 3;

[0084] The preparation method of the above perovskite precursor solution is as follows: N,N-dimethylformamide (DMF) is used as the solvent, the concentration of lead bromide is 0.6 mmol, the concentration of formamidinium bromide is 0.6 mmol, the concentration of phenylethylamine bromide is 0.15 mmol, and the molecular formula is PEA2FA. n-1 Pb n Br 3n+1 (n=8), the above three materials are mixed to form a quasi-two-dimensional perovskite. After thorough stirring at 45°C, the mixture is filtered through a 0.22 μm polytetrafluoroethylene hydrophobic filter membrane to form the perovskite precursor solution.

[0085] Step 3: Load the product obtained in Step 2 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride were sequentially deposited onto the perovskite luminescent layer 3, with 8.5 groups of deposits. The evaporation rate was controlled at 0.4 nm / s. The thickness of each zinc sulfide layer was 58.2 nm, and the thickness of each yttrium fluoride layer was 90.1 nm. A 1.2 μm top distributed Bragg reflector 4 was then deposited.

[0086] Example 4

[0087] The fabrication method of the green perovskite laser provided in Example 4 includes the following steps:

[0088] Step 1: Place the 1mm thick glass substrate 1 into an ultrasonic cleaner for cleaning. After cleaning and wiping, place the cleaned glass substrate 1 into a sample holder. Place the sample holder with the glass substrate 1 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, titanium oxide and silicon dioxide were sequentially deposited onto the glass substrate 1 by evaporation, with 15.5 deposits. The evaporation rate was controlled at 0.4 nm / s. The thickness of each titanium oxide layer was 58.6 nm and the thickness of each silicon dioxide layer was 90.5 nm. In this way, a 2.3 μm bottom distributed Bragg reflector 2 was prepared.

[0089] Step 2: 100 μL of perovskite precursor solution is uniformly drop-coated onto the bottom distributed Bragg reflector 2; 600 μL of dimethyl sulfoxide (DMSO) solution is uniformly sprayed onto the inner wall of the spin coater, and the spin coater is turned off to maintain a sealed space; the spin coater spin coat time is adjusted to 30 s, and the spin coat speed is controlled at 4500 r / min. After the spin coat starts, ether is dropped into the top orifice at 5-6 s; the glass substrate 1 with the perovskite precursor solution spin-coated is placed on a hot plate for annealing at 120°C for 10 minutes to form a 100 nm thick perovskite light-emitting layer 3;

[0090] The preparation method of the above perovskite precursor solution is as follows: N,N-dimethylformamide (DMF) is used as the solvent, the concentration of lead bromide is 0.6 mmol, the concentration of formamidinium bromide is 0.6 mmol, the concentration of phenylethylamine bromide is 0.13 mmol, and the molecular formula is PEA2FA. n-1 Pb n Br 3n+1 (n=9), the above three materials are mixed to form a quasi-two-dimensional perovskite. After thorough stirring at 45°C, the mixture is filtered through a 0.22 μm polytetrafluoroethylene hydrophobic filter membrane to form the perovskite precursor solution.

[0091] Step 3: Load the product obtained in Step 2 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride were sequentially deposited onto the perovskite luminescent layer 3, with 8.5 groups of deposits. The evaporation rate was controlled at 0.4 nm / s. The thickness of each zinc sulfide layer was 58.2 nm, and the thickness of each yttrium fluoride layer was 90.1 nm. A 1.2 μm top distributed Bragg reflector 4 was then deposited.

[0092] Comparative Example 1

[0093] The fabrication method of the green perovskite laser provided in Comparative Example 1 includes the following steps:

[0094] Step 1: Place a 1mm thick glass substrate into an ultrasonic cleaner for cleaning. After cleaning and wiping, place the glass substrate into a sample holder. Then, place the sample holder with the glass substrate into an electron beam coating machine and perform vacuum treatment until the vacuum level reaches 2×10⁻⁶. -3 At Pa, titanium oxide and silicon dioxide were sequentially deposited onto a glass substrate by evaporation. 15.5 layers were deposited, and the evaporation rate was controlled at 0.4 nm / s. The thickness of each titanium oxide layer was 58.6 nm and the thickness of each silicon dioxide layer was 90.5 nm. In this way, a 2.3 μm bottom distributed Bragg reflector was prepared.

[0095] Step 2: Uniformly drop-coat 100 μL of perovskite precursor solution onto the bottom distributed Bragg reflector; adjust the spin coating time of the spin coater to 30 s and control the spin coating speed to 4500 r / min. After starting spin coating, drop ether into the top orifice at 5-6 s; place the glass substrate with the spin-coated perovskite precursor solution on a hot plate for annealing at 120°C for 10 minutes to form a 100 nm thick perovskite light-emitting layer.

[0096] The preparation method of the above perovskite precursor solution is as follows: N,N-dimethylformamide (DMF) is used as the solvent, the concentration of lead bromide is 0.6 mmol, the concentration of formamidinium bromide is 0.6 mmol, the concentration of phenylethylamine bromide is 0.2 mmol, and the molecular formula is PEA2FA. n-1 Pb n Br 3n+1 (n=6), the above three materials are mixed to form a quasi-two-dimensional perovskite. After thorough stirring at 45°C, the mixture is filtered through a 0.22 μm polytetrafluoroethylene hydrophobic filter membrane to form the perovskite precursor solution.

[0097] Step 3: Load the product obtained in Step 2 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride were sequentially deposited onto the perovskite light-emitting layer. The evaporation rate was controlled at 0.4 nm / s. The thickness of each zinc sulfide layer was 58.2 nm, and the thickness of each yttrium fluoride layer was 90.1 nm. A 1.2 μm top distributed Bragg reflector was then deposited.

[0098] Comparative Example 2

[0099] The fabrication method of the green perovskite laser provided in Comparative Example 2 includes the following steps:

[0100] Step 1: Place a 1mm thick glass substrate into an ultrasonic cleaner for cleaning. After cleaning and wiping, place the glass substrate into a sample holder. Then, place the sample holder with the glass substrate into an electron beam coating machine and perform vacuum treatment until the vacuum level reaches 2×10⁻⁶. -3At Pa, titanium oxide and silicon dioxide were sequentially deposited onto a glass substrate by evaporation. 15.5 layers were deposited, and the evaporation rate was controlled at 0.4 nm / s. The thickness of each titanium oxide layer was 58.6 nm and the thickness of each silicon dioxide layer was 90.5 nm. In this way, a 2.3 μm bottom distributed Bragg reflector was prepared.

[0101] Step 2: Uniformly drop-coat 100 μL of perovskite precursor solution onto the bottom distributed Bragg reflector; adjust the spin coating time of the spin coater to 30 s and control the spin coating speed to 4500 r / min. After starting spin coating, drop ether into the top orifice at 5-6 s; place the glass substrate with the spin-coated perovskite precursor solution on a hot plate for annealing at 120°C for 10 minutes to form a 100 nm thick perovskite light-emitting layer.

[0102] The preparation method of the above perovskite precursor solution is as follows: N,N-dimethylformamide (DMF) is used as the solvent, the concentration of lead bromide is 0.6 mmol, the concentration of formamidinium bromide is 0.6 mmol, the concentration of phenylethylamine bromide is 0.17 mmol, and the molecular formula is PEA2FA. n-1 Pb n Br 3n+1 (n=7), the above three materials are mixed to form a quasi-two-dimensional perovskite. After thorough stirring at 45°C, the mixture is filtered through a 0.22 μm polytetrafluoroethylene hydrophobic filter membrane to form the perovskite precursor solution.

[0103] Step 3: Load the product obtained in Step 2 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride were sequentially deposited onto the perovskite light-emitting layer. The evaporation rate was controlled at 0.4 nm / s. The thickness of each zinc sulfide layer was 58.2 nm, and the thickness of each yttrium fluoride layer was 90.1 nm. A 1.2 μm top distributed Bragg reflector was then deposited.

[0104] Comparative Example 3

[0105] The fabrication method of the green perovskite laser provided in Comparative Example 3 includes the following steps:

[0106] Step 1: Place a 1mm thick glass substrate into an ultrasonic cleaner for cleaning. After cleaning and wiping, place the glass substrate into a sample holder. Then, place the sample holder with the glass substrate into an electron beam coating machine and perform vacuum treatment until the vacuum level reaches 2×10⁻⁶. -3 At Pa, titanium oxide and silicon dioxide were sequentially deposited onto a glass substrate by evaporation. 15.5 layers were deposited, and the evaporation rate was controlled at 0.4 nm / s. The thickness of each titanium oxide layer was 58.6 nm and the thickness of each silicon dioxide layer was 90.5 nm. In this way, a 2.3 μm bottom distributed Bragg reflector was prepared.

[0107] Step 2: Uniformly drop-coat 100 μL of perovskite precursor solution onto the bottom distributed Bragg reflector; adjust the spin coating time of the spin coater to 30 s and control the spin coating speed to 4500 r / min. After starting spin coating, drop ether into the top orifice at 5-6 s; place the glass substrate with the spin-coated perovskite precursor solution on a hot plate for annealing at 120°C for 10 minutes to form a 100 nm thick perovskite light-emitting layer.

[0108] The preparation method of the above perovskite precursor solution is as follows: N,N-dimethylformamide (DMF) is used as the solvent, the concentration of lead bromide is 0.6 mmol, the concentration of formamidinium bromide is 0.6 mmol, the concentration of phenylethylamine bromide is 0.15 mmol, and the molecular formula is PEA2FA. n-1 Pb n Br 3n+1 (n=8), the above three materials are mixed to form a quasi-two-dimensional perovskite. After thorough stirring at 45°C, the mixture is filtered through a 0.22 μm polytetrafluoroethylene hydrophobic filter membrane to form the perovskite precursor solution.

[0109] Step 3: Load the product obtained in Step 2 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride were sequentially deposited onto the perovskite light-emitting layer. The evaporation rate was controlled at 0.4 nm / s. The thickness of each zinc sulfide layer was 58.2 nm, and the thickness of each yttrium fluoride layer was 90.1 nm. A 1.2 μm top distributed Bragg reflector was then deposited.

[0110] Comparative Example 4

[0111] The fabrication method of the green perovskite laser provided in Comparative Example 4 includes the following steps:

[0112] Step 1: Place a 1mm thick glass substrate into an ultrasonic cleaner for cleaning. After cleaning and wiping, place the glass substrate into a sample holder. Then, place the sample holder with the glass substrate into an electron beam coating machine and perform vacuum treatment until the vacuum level reaches 2×10⁻⁶. -3 At Pa, titanium oxide and silicon dioxide were sequentially deposited onto a glass substrate by evaporation. 15.5 layers were deposited, and the evaporation rate was controlled at 0.4 nm / s. The thickness of each titanium oxide layer was 58.6 nm and the thickness of each silicon dioxide layer was 90.5 nm. In this way, a 2.3 μm bottom distributed Bragg reflector was prepared.

[0113] Step 2: Uniformly drop-coat 100 μL of perovskite precursor solution onto the bottom distributed Bragg reflector; adjust the spin coating time of the spin coater to 30 s and control the spin coating speed to 4500 r / min. After starting spin coating, drop ether into the top orifice at 5-6 s; place the glass substrate with the spin-coated perovskite precursor solution on a hot plate for annealing at 120°C for 10 minutes to form a 100 nm thick perovskite light-emitting layer.

[0114] The preparation method of the above perovskite precursor solution is as follows: N,N-dimethylformamide (DMF) is used as the solvent, the concentration of lead bromide is 0.6 mmol, the concentration of formamidinium bromide is 0.6 mmol, the concentration of phenylethylamine bromide is 0.15 mmol, and the molecular formula is PEA2FA. n-1 Pb n Br 3n+1 (n=9), the above three materials are mixed to form a quasi-two-dimensional perovskite. After thorough stirring at 45°C, the mixture is filtered through a 0.22 μm polytetrafluoroethylene hydrophobic filter membrane to form the perovskite precursor solution.

[0115] Step 3: Load the product obtained in Step 2 into an electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride were sequentially deposited onto the perovskite light-emitting layer. The evaporation rate was controlled at 0.4 nm / s. The thickness of each zinc sulfide layer was 58.2 nm, and the thickness of each yttrium fluoride layer was 90.1 nm. A 1.2 μm top distributed Bragg reflector was then deposited.

[0116] Through the above embodiments and comparative examples, it can be understood that:

[0117] from Figure 2 As can be seen, the absorption spectrum of Example 1, which underwent dimethyl sulfoxide (DMSO) assisted crystallization, showed a significant increase in absorption at 439 nm compared to the absorption spectrum of Comparative Example 1, which did not undergo dimethyl sulfoxide (DMSO) assisted crystallization. This indicates that the content of the n=2 phase increased, and the dimethyl sulfoxide (DMSO) atmosphere exerted a regulatory effect on the formation of the perovskite quasi-two-dimensional phase, which was beneficial to the energy transfer process from the small n phase (n=2) to the large n phase (n≥5).

[0118] from Figure 3 As can be seen, the photoluminescence of Example 1, which was crystallized with dimethyl sulfoxide (DMSO) assistance, was stronger than that of Comparative Example 1, which was not crystallized with dimethyl sulfoxide (DMSO) assistance. This indicates that crystallization with dimethyl sulfoxide (DMSO) assistance can enhance the radiative recombination of perovskite crystals, thereby enabling the fabrication of green perovskite lasers.

[0119] from Figure 4As can be seen, under pulsed laser pumping, the full width at half maximum (FWHM) of the fluorescence spectrum of the perovskite film in Comparative Example 1 narrowed, and the intensity of the fluorescence spectrum increased nonlinearly, indicating that the film exhibited amplified spontaneous emission (ASE) and had a low threshold at room temperature.

[0120] from Figure 5 As can be seen, under pulsed laser pumping, the full width at half maximum (FWHM) of the fluorescence spectrum of the perovskite thin film in Example 1 narrowed, and the intensity of the fluorescence spectrum increased nonlinearly, indicating that the thin film exhibited amplified spontaneous emission (ASE) phenomenon. Figure 4 The comparison reveals that the threshold of the film in Example 1 is lower than that of the film in Comparative Example 1, indicating that the film with dimethyl sulfoxide (DMSO) assisted crystallization has better crystal quality and is more likely to realize the fabrication of green perovskite lasers.

[0121] from Figure 6 As can be seen, in Example 1, the fluorescence spectrum half-width was extremely narrowed under continuous laser pumping, and the fluorescence spectrum underwent nonlinear growth. A perovskite laser with continuous optical pumping at room temperature was realized under the gain of the optical microcavity, and it has an extremely low threshold.

[0122] On the other hand, Table 1 below compares the laser parameters of Comparative Examples 1, 2, 3, and 4 with those of Examples 1, 2, 3, and 4. Compared to Comparative Example 1, Example 1 has a lower threshold and a narrower half-width. Similarly, compared to Comparative Examples 2, 3, and 4, Examples 2, 3, and 4 also have lower thresholds and narrower linewidths, respectively. This demonstrates that the embodiments of the present invention exhibit superior laser characteristics compared to their respective comparative examples, thus illustrating the significant advantages of the method of the present invention in improving the performance of green perovskite lasers.

[0123] Table 1

[0124]

[0125] The green perovskite laser and its fabrication method of the present invention delay the crystallization process of perovskite by using a dimethyl sulfoxide (DMSO) atmosphere, thereby controlling the phase distribution inside the quasi-two-dimensional perovskite, resulting in lower optical loss and faster internal energy transfer of the perovskite film. The combination of the perovskite film and the distributed Bragg mirror realizes a low-threshold laser device continuously pumped by laser at room temperature.

[0126] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A green perovskite laser, comprising a substrate (1), and a bottom distributed Bragg mirror (2), a perovskite light-emitting layer (3) and a top distributed Bragg mirror (4) sequentially disposed on the substrate (1); Its features are, The bottom distributed Bragg mirror (2) is an alternating structure of high-refractive-index titanium dioxide and low-refractive-index silicon dioxide; The perovskite luminescent layer (3) is a quasi-two-dimensional perovskite component crystallized with the aid of an atmosphere created by dimethyl sulfoxide (DMSO); The top distributed Bragg reflector (4) is an alternating structure of high-refractive-index zinc sulfide and low-refractive-index yttrium fluoride.

2. The green perovskite laser according to claim 1, characterized in that, The molecular formula of the quasi-two-dimensional perovskite component is PEA2FA. n-1 Pb n Br 3n+1 , where n = 6-9, is a quasi-two-dimensional perovskite formed by mixing three materials: lead bromide with a concentration of 0.4-0.8 mmol, formamidin bromide with a concentration of 0.4-0.8 mmol, and phenylethylamine bromide with a concentration of 0.1-0.3 mmol.

3. The green perovskite laser according to claim 1, characterized in that, The thickness of each layer of titanium oxide in the bottom distributed Bragg reflector (2) is 30-70 nm, and the thickness of each layer of silicon dioxide is 80-100 nm.

4. The green perovskite laser according to claim 1, characterized in that, The bottom distributed Bragg reflector (2) consists of 15.5 sets of alternating structures of high-refractive-index titanium dioxide and low-refractive-index silicon dioxide, with a reflectivity of 99.9% and a thickness of 2-3 μm.

5. The green perovskite laser according to claim 1, characterized in that, The thickness of each zinc sulfide layer in the top distributed Bragg reflector (4) is 30-70 nm, and the thickness of each yttrium fluoride layer is 80-100 nm.

6. The green perovskite laser according to claim 1, characterized in that, The top distributed Bragg reflector (4) consists of 8.5 sets of alternating structures of high-refractive-index zinc sulfide and low-refractive-index yttrium fluoride, with a reflectivity of 99% and a thickness of 1-2 μm.

7. A method for fabricating a green perovskite laser according to any one of claims 1-6, characterized in that, Includes the following steps: S1. A bottom distributed Bragg mirror (2) is fabricated on a substrate (1); S2. Create a dimethyl sulfoxide (DMSO) atmosphere in a closed spin coater; S3. A perovskite light-emitting layer (3) is grown on the bottom distributed Bragg reflector (2); S4. A top distributed Bragg reflector (4) is deposited on the perovskite light-emitting layer (3).

8. The method for fabricating a green perovskite laser according to claim 7, characterized in that, The dimethyl sulfoxide (DMSO) atmosphere mentioned in step S2 is created by uniformly spraying 200-1000 μL of dimethyl sulfoxide (DMSO) inside a sealed spin coater.

9. The method for fabricating a green perovskite laser according to claim 7, characterized in that, The preparation method of the perovskite precursor solution used in step S3 to grow the perovskite luminescent layer (3) is as follows: Using N,N-dimethylformamide (DMF) as solvent, lead bromide (0.4-0.8 mmol), formamidinium bromide (0.4-0.8 mmol), and phenylethylammonium bromide (0.1-0.3 mmol) are mixed to form a quasi-two-dimensional perovskite with the molecular formula PEA2FA. n-1 Pb n Br 3n+1 Where n = 6-9, after thorough stirring at 20℃-80℃, the perovskite precursor solution is formed by filtration through a 0.22μm polytetrafluoroethylene hydrophobic filter membrane.

10. The method for fabricating a green perovskite laser according to claim 7, characterized in that, One specific implementation method is as follows: Step S1 specifically includes the following steps: S11. Place the glass substrate (1) into the ultrasonic cleaner for cleaning, and place the cleaned and wiped glass substrate (1) into the sample holder. S12. The sample holder with the glass substrate (1) is placed into the electron beam coating machine and vacuum treatment is performed. When the vacuum degree reaches 2×10 -3 At Pa, titanium oxide and silicon dioxide were sequentially deposited onto a glass substrate (1) for 15.5 groups, with the evaporation rate controlled at 0.35 to 0.45 nm / s, to prepare a bottom distributed Bragg reflector (2). Step S2 specifically includes the following steps: S21. 100 μL of perovskite precursor solution is uniformly drop-coated onto the bottom distributed Bragg mirror (2); S22. Spray 200-1000μL of dimethyl sulfoxide (DMSO) solution evenly onto the inner wall of the spin coater, and then turn off the spin coater to maintain a sealed space. Step S3 specifically includes the following steps: S31. Adjust the spin coating time of the spin coater to 30s, control the spin coating speed to 3000-5000r / min, and drip ether into the top hole at 5-6s after starting spin coating; S32. Place the glass substrate (1) with the spin-coated perovskite precursor solution on a hot stage for annealing to form a perovskite light-emitting layer (3), and form a quasi-two-dimensional perovskite crystal with high crystallinity, low surface roughness and rapid energy transfer on the bottom distributed Bragg reflector (2). Step S4 specifically includes the following steps: S41. Place the sample holder from step S3 into the electron beam coating machine and perform vacuum treatment until the vacuum degree reaches 2×10⁻⁶. -3 At Pa, zinc sulfide and yttrium fluoride were sequentially deposited onto the perovskite light-emitting layer (3) for 8.5 groups, with the evaporation rate controlled at 0.35-0.45 nm / s, to prepare a quasi-two-dimensional green perovskite laser with a microcavity structure that can realize green light emission.

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