Method for continuously synthesizing ion-doped perovskite nanocrystals based on acoustic micro-mixer
By using an acoustic micro-mixer to mix perovskite precursor solution and doped ion precursor solution in a microchannel, the problems of uneven mixing and complex equipment in existing technologies are solved, and efficient and precise synthesis of perovskite nanocrystals and improved thermal stability are achieved.
Patent Information
- Application Number
- CN202511090659.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-05
- Publication Date
- 2025-11-11
AI Technical Summary
In the existing technology, the synthesis methods of ion-doped perovskite nanocrystals are characterized by high energy consumption, high equipment cost, complex and discontinuous operation, making it difficult to achieve large-scale production. In addition, the traditional magnetic stirring method leads to uneven mixing, which affects the uniformity of nanoparticle size and product quality.
By employing an acoustic micromixer combined with ion doping technology, the perovskite precursor solution, antisolvent, and doped ion precursor solution are mixed within a microchannel through the sharp edge structure and bubble trapping groove of the acoustic micromixer, achieving millisecond-level mixing, controlling the nucleation and growth of nanocrystals, and ensuring uniformity and high efficiency.
The efficient and precise synthesis of perovskite nanocrystals was achieved, resulting in uniform nanocrystal size, improved thermal stability, reduced byproducts, and suitability for large-scale production.
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Figure CN120919931A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of perovskite synthesis technology, and in particular to a method for the continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer. Background Technology
[0002] All-inorganic cesium lead halide (CsPbBr3) perovskite nanocrystals have shown great application potential in fields such as solar cells, but the material has significant drawbacks such as poor stability and the toxicity of lead, which limit its practical application.
[0003] Ion doping is a common technique for improving the stability of all-inorganic cesium lead halide perovskite nanocrystals. In existing technologies, the main reaction routes for synthesizing doped nanocrystals include high-temperature thermal injection and post-synthesis ion exchange. While these methods have been proven to synthesize doped nanocrystals, they have significant limitations: they require high reaction temperatures, leading to high energy consumption; they necessitate additional vacuum equipment, increasing equipment costs and operational complexity; and the discontinuous operation results in low production efficiency, making it difficult to meet the demands of large-scale preparation.
[0004] To achieve room-temperature synthesis of perovskite nanocrystals, researchers proposed a ligand-assisted reprecipitation (LARP) method. This method utilizes the polarity differences of perovskite precursors in different solvents to generate a supersaturated state, thereby initiating nucleation and crystal growth. Therefore, local supersaturation has a significant impact on the nucleation and growth rate of CsPbX3 nanocrystals (NCs). Controlling the effective and rapid mixing of the good solvent and antisolvent, and thus precisely regulating the local supersaturation, is a key step in the crystallization process. However, most LARP-based processes for synthesizing perovskite quantum dots employ traditional magnetic stirring, which results in slow mixing speeds, difficulty in providing a uniform nucleation environment, leading to non-uniform nanoparticle sizes and the generation of unwanted byproducts, thus affecting product quality. Summary of the Invention
[0005] The purpose of this invention is to provide a method for the continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer. By combining ion doping with micromixing technology, this method solves the problems of low mixing efficiency, difficulty in controlling the doping ratio, and numerous by-products in traditional doping processes, and achieves efficient and precise synthesis of perovskite nanocrystals.
[0006] To achieve the above objectives, this invention provides a method for the continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer, comprising the following steps:
[0007] S1. Preparation of perovskite precursor solution and doped ion precursor solution;
[0008] S2. Inject the perovskite precursor solution, antisolvent, and doped ion precursor solution into the acoustic micromixer through three independent inlets of the acoustic micromixer respectively, and adjust the flow rate range of the three independent inlets to be 10 - 2500 μL / min;
[0009] S3. The side wall of the microchannel of the acoustic micromixer is provided with periodically distributed sharp edge structures and bubble capture grooves, and control the mixing of the perovskite precursor solution, antisolvent, and doped ion precursor solution in the microchannel, with the mixing time 1 ms ≤ t ≤ 5 ms;
[0010] S4. Collect the product at the outlet of the acoustic micromixer into a sample bottle to obtain La 3+ doped CsPb x La 1-x Br3(0.5 < x < 1.0) nanocrystal colloidal solution, and after standing, wash and centrifuge to obtain La 3+ doped CsPb x La 1-x Br3 nanocrystals.
[0011] Preferably, in S1, to prepare the perovskite precursor solution, dissolve CsBr, PbBr2, oleylamine, and oleic acid in dry dimethylformamide to prepare a perovskite precursor solution with the concentration of each component being 0.03 - 0.05 mmol / mL.
[0012] Preferably, in S1, to prepare the doped ion precursor solution, dissolve LaBr3, oleylamine, and oleic acid in dry dimethylformamide to prepare a doped ion precursor solution with the concentration of each component being 0.03 - 0.05 mmol / mL.
[0013] Preferably, in S2, the antisolvent is isopropanol, and the volume ratio of the perovskite precursor solution, antisolvent, and doped ion precursor solution injected into the acoustic micromixer is 1:10:m, where 0 < m ≤ 0.5.
[0014] Preferably, in S2, the acoustic micromixer includes a piezoelectric transducer and a microfluidic chip. The piezoelectric transducer is arranged at the bottom of the microfluidic chip. The microfluidic chip includes a microchannel. One end of the microchannel is connected with several independent inlets, and a flow control device is arranged at each independent inlet. The other end of the microchannel is connected with an outlet.
[0015] Preferably, in S2, the flow rate ratio of the perovskite precursor solution to the doped ion precursor solution is 1:0.1 - 0.5.
[0016] Preferably, in S3, sharp edge structures are alternately distributed on both sides of the microchannel, and a bubble trap is disposed on one of the sides of the microchannel. The bubble trap is alternately disposed with the sharp edge structures on the same sidewall and corresponds to the position of the sharp edge structures on the opposite sidewall.
[0017] Preferably, in S3, the depth of the microchannel is 100μm and the width of the main channel of the microchannel is 600μm.
[0018] Preferably, in S3, the distance between the top of the sharp edge structure and the sidewall is 300 μm, the angle of the apex of the sharp edge structure is 15°, and the distance between the apex of two adjacent sharp edge structures on the same sidewall is 600 μm.
[0019] Preferably, in S3, the mixing temperature is 25-30℃.
[0020] The beneficial effects of this invention are:
[0021] (1) The acoustic micro-mixer of the present invention has millisecond-scale mixing capability to ensure effective collision and bonding of reactive particles, and can be completely mixed in as little as 5ms, providing sufficient supersaturation for the nucleation of nanocrystals, while providing sufficient time for the growth of nanocrystals in the channel, and providing a uniform nucleation environment for the nucleation and growth of nanocrystals.
[0022] (2) In this invention, the doping amount of the dopant ions can be precisely controlled by adjusting the flow rate of the dopant ion precursor solution, which can significantly improve the size characteristics of the nanocrystals and make the obtained CsPb x La 1-x The overall particle size of Br3 nanocrystals is reduced, the size distribution is more uniform, the original crystal structure is maintained, and the thermal stability is improved.
[0023] (3) The acoustic micro-mixer in this invention effectively improves the problem of dirt and blockage of nanoparticles in microfluidic devices by setting periodically distributed sharp edge structures and bubble trapping grooves on the sidewall of the microchannel.
[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the acoustic micromixer microfluidic chip of Embodiment 1 of the present invention;
[0026] Figure 2 This is a schematic diagram of the process for the continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer according to the present invention.
[0027] Figure 3These are TEM images and nanocrystal edge length distribution diagrams of the perovskite nanocrystals of this invention. Figure 3 In the diagram, 'a' is the TEM image of Comparative Example 1. Figure 3 In the image, b is a TEM image from Example 5. Figure 3 In the image, c is the TEM image of Example 4. Figure 3 In the diagram, 'e' represents the edge length distribution of the nanocrystals in Comparative Example 1. Figure 3 In the figure, f is the edge length distribution diagram of the nanocrystals in Example 5. Figure 3 In the figure, g represents the edge length distribution of nanocrystals in Example 4;
[0028] Figure 4 This is the XRD pattern of the perovskite nanocrystals of the present invention;
[0029] Figure 5 This is the PL emission spectrum of the perovskite nanocrystals of this invention;
[0030] Figure 6 This is the ultraviolet-visible absorption spectrum of the perovskite nanocrystals of the present invention;
[0031] Figure 7 This is a graph showing the PL emission spectrum and peak value of the perovskite nanocrystals of the present invention at different temperatures as a function of temperature. Figure 7 In the figure, 'a' represents the PL emission spectrum at different temperatures. Figure 7 In the graph, b represents the peak value as a function of temperature.
[0032] Figure 8 These are XPS images of the perovskite nanocrystals of Example 4 and Comparative Example 1 of this invention. Figure 8 In the figure, 'a' represents the XPS spectra of the Cs 3d orbitals in Example 4 and Comparative Example 1. Figure 8 In the figure, b represents the XPS spectra of the Br 3d orbitals in Example 4 and Comparative Example 1. Figure 8 In the figure, c represents the XPS spectra of the Pb 4f orbitals in Example 4 and Comparative Example 1. Figure 8 In the figure, d represents the full-spectrum XPS comparison diagram of Example 4 and Comparative Example 1.
[0033] Figure label:
[0034] 1. Microchannel; 2. Independent inlet; 3. Outlet; 4. Sharp edge structure; 5. Bubble trap. Detailed Implementation
[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.
[0036] The present invention provides a method for continuously synthesizing ion-doped perovskite nanocrystals based on an acoustic micromixer, comprising the following steps:
[0037] S1. Prepare a perovskite precursor solution and a doped ion precursor solution;
[0038] S2. Inject the perovskite precursor solution, an antisolvent, and the doped ion precursor solution into the acoustic micromixer through three independent inlets of the acoustic micromixer respectively, and adjust the flow rate range of the three independent inlets to be 10 - 2500 μL / min;
[0039] S3. The side wall of the microchannel of the acoustic micromixer is provided with periodically distributed sharp edge structures and bubble capture grooves, and control the mixing of the perovskite precursor solution, the antisolvent, and the doped ion precursor solution in the microchannel, with a mixing time of 1 ms ≤ t ≤ 5 ms;
[0040] S4. Collect the product at the outlet of the acoustic micromixer into a sample bottle to obtain a La 3+ doped CsPb x La 1-x Br3 (0.5 < x < 1.0) nanocrystal colloidal solution, and after standing, wash and centrifuge to obtain La 3+ doped CsPb x La 1-x Br3 nanocrystals.
[0041] The La 3+ doped CsPb x La 1-x Br3 nanocrystals
[0042] Preferably, in S1, the perovskite precursor solution is prepared by dissolving CsBr, PbBr2, oleylamine, and oleic acid in dry dimethylformamide to prepare a perovskite precursor solution with the concentration of each component being 0.03 - 0.05 mmol / mL.
[0043] In some specific embodiments of the present invention, the concentration of CsBr in the perovskite precursor solution is 0.04 mmol / mL, and the concentration of PbBr2 is 0.04 mmol / mL.
[0044] Preferably, in S1, the doped ion precursor solution is prepared by dissolving LaBr3, oleylamine, and oleic acid in dry dimethylformamide to prepare a doped ion precursor solution with the concentration of each component being 0.03 - 0.05 mmol / mL.
[0045] In some specific embodiments of the present invention, the concentration of LaBr3 in the doped ion precursor solution is 0.04 mmol / mL.
[0046] Preferably, in S2, the antisolvent is isopropanol, and the volume ratio of the perovskite precursor solution, the antisolvent, and the doped ion precursor solution injected into the acoustic micromixer is 1:10:m. <m≤0.5。
[0047] In some specific embodiments of the present invention, m = 0.1, 0.3, or 0.5.
[0048] Preferably, in S2, the acoustic micro-mixer includes a piezoelectric transducer and a microfluidic chip. The piezoelectric transducer is located at the bottom of the microfluidic chip, which includes a microchannel. One end of the microchannel is connected to several independent inlets, and each independent inlet is equipped with a flow control device. The other end of the microchannel is connected to an outlet.
[0049] Preferably, in S2, the flow rate ratio of the perovskite precursor solution to the doped ion precursor solution is 1:0.1-0.5.
[0050] Preferably, in S3, sharp edge structures are alternately distributed on both sides of the microchannel, and a bubble trap is disposed on one of the sides of the microchannel. The bubble trap is alternately disposed with the sharp edge structures on the same sidewall and corresponds to the position of the sharp edge structures on the opposite sidewall.
[0051] Preferably, in S3, the depth of the microchannel is 100μm and the width of the main channel of the microchannel is 600μm.
[0052] Preferably, in S3, the distance between the top of the sharp edge structure and the sidewall is 300 μm, the angle of the apex of the sharp edge structure is 15°, and the distance between the apex of two adjacent sharp edge structures on the same sidewall is 600 μm.
[0053] Preferably, in S3, the mixing temperature is 25-30℃.
[0054] Example 1
[0055] like Figure 1 As shown, the acoustic micromixer used in this invention includes a piezoelectric transducer and a microfluidic chip. The piezoelectric transducer is disposed at the bottom of the microfluidic chip, which includes a microchannel 1. One end of the microchannel 1 is connected to several independent inlets 2, and each independent inlet 2 is equipped with a flow control device. The other end of the microchannel 1 is connected to an outlet 3. By applying an AC signal to the piezoelectric transducer, the transducer converts electrical energy into acoustic wave vibrations. The generated acoustic waves pass through the microfluidic chip, thereby driving the fluid mixing process within the microchannel 1.
[0056] The microchannel 1 has periodically distributed sharp edge structures 4 and bubble trapping grooves 5 on its sidewalls. The sharp edge structures 4 are alternately distributed on both sides of the microchannel 1, and the bubble trapping grooves 5 are set on one sidewall of the microchannel 1. The bubble trapping grooves 5 are alternately arranged with the sharp edge structures 4 on the same sidewall, and their positions correspond to those of the sharp edge structures 4 on the opposite sidewall.
[0057] As the acoustic waves propagate along the substrate of the microfluidic chip, they force the sharp edge structure 4 within the microchannel 1 to generate a reverse rotating vortex around its tip. Simultaneously, the bubbles captured by the bubble trapping groove 5 vibrate under the drive of the acoustic waves, forming a strong recirculating flow pattern in the surrounding fluid, creating a dual disturbance effect. The synergistic effect of the vortex from the sharp edge structure 4 and the vibrating flow from the bubbles enables rapid and efficient mixing of the perovskite precursor solution, antisolvent, and doped ion precursor solution, providing favorable conditions for the uniform nucleation and growth of nanocrystals, thereby ensuring the prepared La... 3+ CsPb doping x La 1-x Br3 nanocrystals have uniform size and stable performance.
[0058] Microchannel 1 has a depth of 100 μm and a main channel width of 600 μm, providing suitable flow space for the fluid. This ensures a certain flow rate (suitable for flow rates of 10-2500 μL / min) while allowing the fluid to form effective turbulent vortices under acoustic drive. The distance between the top of the sharp edge structure 4 and the sidewall is 300 μm. This 300 μm spacing allows the fluid to generate strong local shear forces and counter-rotating vortices between the sharp edge structure 4 and the sidewall under acoustic vibration, enhancing the fluid turbulence intensity, promoting rapid fusion of multiphase fluids, and avoiding local supersaturation differences caused by insufficient mixing. The apex angle of the sharp edge structure 4 is 15°, maximizing the local turbulence effect when the fluid flows through it. When the sharp edge vibrates driven by sound waves, the acute-angled structure concentrates energy, forming high-intensity acoustic vortices around the tip, strengthening the turbulence effect on adjacent fluids, and further improving mixing efficiency. The distance between the apex of two adjacent sharp edge structures 4 on the same sidewall is 600 μm, ensuring that the sharp edge structures 4 are uniformly distributed within the channel. This allows the fluid to be continuously disturbed as it flows through the entire microchannel 1, achieving full-channel mixing. The uniformly distributed structure avoids local mixing dead zones, ensuring consistent mixing at all locations within the microchannel 1. This controls the uniformity of the nanocrystal nucleation and growth environment, ultimately yielding uniformly sized La... 3+ CsPbxLa doped 1-x Br3 nanocrystals.
[0059] Example 2
[0060] like Figure 2As shown, a method for continuously synthesizing ion-doped perovskite nanocrystals based on an acoustic micromixer includes the following steps:
[0061] S1. Prepare a perovskite precursor solution and a doped ion precursor solution;
[0062] S1.1. Dissolve CsBr (0.6 mmol), PbBr2 (0.6 mmol), oleylamine (1 mL), and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a perovskite precursor solution.
[0063] S1.2. Dissolve LaBr3 (0.6 mmol), oleylamine (1 mL), and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a doped ion precursor solution.
[0064] S2. Inject the perovskite precursor solution, the antisolvent isopropanol, and the doped ion precursor solution into the acoustic micromixer through three independent inlets of the acoustic micromixer respectively. Adjust the flow rates of the perovskite precursor solution and the isopropanol inlets to 150 μL / min and 1500 μL / min respectively, and adjust the flow rate of the doped ion precursor solution inlet to 45 μL / min. The volume ratio of the perovskite precursor solution, the antisolvent, and the doped ion precursor solution in the acoustic micromixer is 1:10:m, where m = 0.3.
[0065] S3. Control the mixing of the perovskite precursor solution, the antisolvent, and the doped ion precursor solution in the microchannel, with a mixing time of 1 ms ≤ t ≤ 5 ms and a mixing temperature of 25°C.
[0066] S4. Collect the product at the outlet of the acoustic micromixer into a sample bottle to obtain a La 3+ doped CsPb x La 1-x Br3 (0.5 < x < 1.0) nanocrystal colloidal solution. Let it stand for 1 hour to remove extremely large nanoparticles, discard the precipitate at the bottom of the sample bottle, wash it three times with ethyl acetate to remove any unreacted ligands, and centrifuge it at 7000 rpm for five minutes. Obtain La 3+ doped CsPb x La 1-x Br3 nanocrystals.
[0067] Example 3
[0068] A method for continuously synthesizing ion-doped perovskite nanocrystals based on an acoustic micromixer includes the following steps:
[0069] S1. Prepare a perovskite precursor solution and a doped ion precursor solution;
[0070] S1.1. Dissolve CsBr (1.0 mmol), PbBr2 (1.0 mmol), oleylamine (1 mL) and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a perovskite precursor solution.
[0071] S1.2. Dissolve LaBr3 (1.0 mmol), oleylamine (1 mL) and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a doped ion precursor solution.
[0072] S2. Inject the perovskite precursor solution, the antisolvent isopropanol and the doped ion precursor solution into the acoustic micromixer through three independent inlets of the acoustic micromixer respectively. Adjust the flow rates of the perovskite precursor solution and the isopropanol inlets to 150 μL / min and 1500 μL / min respectively, and adjust the flow rate of the doped ion precursor solution inlet to 45 μL / min. The volume ratio of the perovskite precursor solution, the antisolvent and the doped ion precursor solution in the acoustic micromixer is 1:10:m, where m = 0.3.
[0073] S3. Control the mixing of the perovskite precursor solution, the antisolvent and the doped ion precursor solution in the microchannel, with a mixing time of 1 ms ≤ t ≤ 5 ms and a mixing temperature of 25 °C.
[0074] S4. Collect the product at the outlet of the acoustic micromixer into a sample bottle to obtain a La 3+ doped CsPb x La 1-x Br3 (0.5 < x < 1.0) nanocrystal colloidal solution. Let it stand for 1 hour to remove extremely large nanoparticles, discard the precipitate at the bottom of the sample bottle, wash it three times with ethyl acetate to remove any unreacted ligands, and centrifuge it at 7000 rpm for five minutes. Obtain La 3+ doped CsPb x La 1-x Br3 nanocrystals.
[0075] Example 4
[0076] A method for continuously synthesizing ion-doped perovskite nanocrystals based on an acoustic micromixer, comprising the following steps:
[0077] S1. Prepare a perovskite precursor solution and a doped ion precursor solution;
[0078] S1.1. Dissolve CsBr (0.8 mmol), PbBr2 (0.8 mmol), oleylamine (1 mL) and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a perovskite precursor solution.
[0079] S1.2. Dissolve LaBr3 (0.8 mmol), oleylamine (1 mL), and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a doped ion precursor solution.
[0080] S2. Inject the perovskite precursor solution, the antisolvent isopropanol, and the doped ion precursor solution into the acoustic micromixer through three independent inlets of the acoustic micromixer respectively. Adjust the flow rates of the perovskite precursor solution and the isopropanol inlet to 150 μL / min and 1500 μL / min respectively, and adjust the flow rate of the doped ion precursor solution inlet to 45 μL / min. The volume ratio of the perovskite precursor solution, the antisolvent, and the doped ion precursor solution in the acoustic micromixer is 1:10:m, where m = 0.3.
[0081] S3. Control the mixing of the perovskite precursor solution, the antisolvent, and the doped ion precursor solution in the microchannel. The mixing time is 1 ms ≤ t ≤ 5 ms, and the mixing temperature is 25 °C.
[0082] S4. Collect the product at the outlet of the acoustic micromixer into a sample bottle to obtain La 3+ doped CsPb x La 1-x Br3 (0.5 < x < 1.0) nanocrystal colloidal solution. Let it stand for 1 hour to remove extremely large nanoparticles. Discard the precipitate at the bottom of the sample bottle, wash it three times with ethyl acetate to remove any unreacted ligands, and centrifuge at 7000 rpm for five minutes. Obtain La 3+ doped CsPb x La 1-x Br3 nanocrystals.
[0083] Example 5
[0084] A method for continuously synthesizing ion-doped perovskite nanocrystals based on an acoustic micromixer, comprising the following steps:
[0085] S1. Prepare a perovskite precursor solution and a doped ion precursor solution;
[0086] S1.1. Dissolve CsBr (0.8 mmol), PbBr2 (0.8 mmol), oleylamine (1 mL), and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a perovskite precursor solution.
[0087] S1.2. Dissolve LaBr3 (0.8 mmol), oleylamine (1 mL), and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a doped ion precursor solution.
[0088] S2. Inject the perovskite precursor solution, the antisolvent isopropanol, and the doped ion precursor solution into the acoustic micromixer through three independent inlets of the acoustic micromixer respectively. Adjust the flow rates of the perovskite precursor solution and the isopropanol inlets to 150 μL / min and 1500 μL / min respectively, and adjust the flow rate of the doped ion precursor solution inlet to 15 μL / min. The volume ratio of the perovskite precursor solution, the antisolvent, and the doped ion precursor solution in the acoustic micromixer is 1:10:m, where m = 0.1.
[0089] S3. Control the mixing of the perovskite precursor solution, the antisolvent, and the doped ion precursor solution in the microchannel. The mixing time is 1 ms ≤ t ≤ 5 ms, and the mixing temperature is 20 °C.
[0090] S4. Collect the product at the outlet of the acoustic micromixer into a sample bottle to obtain La 3+ doped CsPb x La 1-x Br3 (0.5 < x < 1.0) nanocrystal colloidal solution. Let it stand for 1 hour to remove extremely large nanoparticles. Discard the precipitate at the bottom of the sample bottle. Wash it three times with ethyl acetate to remove any unreacted ligands, and centrifuge it at 7000 rpm for five minutes. Obtain La 3+ doped CsPb x La 1-x Br3 nanocrystals.
[0091] Example 6
[0092] A method for continuously synthesizing ion-doped perovskite nanocrystals based on an acoustic micromixer, comprising the following steps:
[0093] S1. Prepare a perovskite precursor solution and a doped ion precursor solution;
[0094] S1.1. Dissolve CsBr (0.8 mmol), PbBr2 (0.8 mmol), oleylamine (1 mL), and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a perovskite precursor solution.
[0095] S1.2. Dissolve LaBr3 (0.8 mmol), oleylamine (1 mL), and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a doped ion precursor solution.
[0096] S2. Inject the perovskite precursor solution, the antisolvent isopropanol, and the doped ion precursor solution into the acoustic micromixer through three independent inlets of the acoustic micromixer respectively. Adjust the flow rates of the perovskite precursor solution and the isopropanol inlet to 150 μL / min and 1500 μL / min respectively, and adjust the flow rate of the doped ion precursor solution inlet to 75 μL / min. The volume ratio of the perovskite precursor solution, the antisolvent, and the doped ion precursor solution in the acoustic micromixer is 1:10:m, where m = 0.5.
[0097] S3. Control the mixing of the perovskite precursor solution, the antisolvent, and the doped ion precursor solution in the microchannel. The mixing time is 1 ms ≤ t ≤ 5 ms, and the mixing temperature is 30 °C.
[0098] S4. Collect the product at the outlet of the acoustic micromixer into a sample bottle to obtain La 3+ doped CsPb x La 1-x Br3(0.5 < x < 1.0) nanocrystal colloidal solution. Let it stand for 1 hour to remove extremely large nanoparticles. Discard the precipitate at the bottom of the sample bottle, wash it three times with ethyl acetate to remove any unreacted ligands, and centrifuge it at 7000 rpm for five minutes. Obtain La 3+ doped CsPb x La 1-x Br3 nanocrystals.
[0099] Comparative Example 1
[0100] A method for continuously synthesizing perovskite nanocrystals based on an acoustic micromixer, comprising the following steps:
[0101] S1. Prepare a perovskite precursor solution;
[0102] Dissolve CsBr (0.8 mmol), PbBr2 (0.8 mmol), oleylamine (1 mL), and oleic acid (2 mL) in dry dimethylformamide (20 mL) to prepare a perovskite precursor solution.
[0103] S2. Inject the perovskite precursor solution and the antisolvent isopropanol into the acoustic micromixer through two independent inlets of the acoustic micromixer respectively. Adjust the flow rates of the perovskite precursor solution and the isopropanol inlet to 150 μL / min and 1500 μL / min respectively. The volume ratio of the perovskite precursor solution and the antisolvent in the acoustic micromixer is 1:10.
[0104] S3. Control the mixing of the perovskite precursor solution and the antisolvent in the microchannel. The mixing time is 1 ms ≤ t ≤ 5 ms, and the mixing temperature is 25 °C.
[0105] S4. Collect the product from the acoustic micromixer outlet into a sample vial to obtain a CsPbBr3 nanoparticle colloidal solution. Let it stand for 1 hour to remove extremely large nanoparticles. Discard the precipitate at the bottom of the sample vial. Wash with three times the amount of ethyl acetate to remove any unreacted ligands, and centrifuge at 7000 rpm for five minutes to obtain CsPbBr3 nanocrystals.
[0106] Performance testing
[0107] The surface morphology of the perovskite nanocrystals prepared in Examples 4, 5 and Comparative Example 1 was characterized by transmission electron microscopy (TEM).
[0108] like Figure 3 As shown, Comparative Example 1 is undoped La. 3+ The perovskite nanocrystals have a size of 42.7 ± 22.9 nm, a relatively large particle size, a wide distribution range, and high dispersion. Example 5: La 3+ When the doping concentration is 10%, the nanocrystal size is 22.4 ± 9.98 nm, which is significantly smaller than that of the undoped sample, and remains within a relatively uniform range. Example 4 La 3+ When the doping amount is 30%, the size of the nanocrystals is 19.9±6.44nm, which is significantly reduced in size, more concentrated in distribution, and has low dispersion.
[0109] It can be seen that the incorporation of lanthanum ions can effectively reduce the size of CsPbBr3 nanocrystals and improve their size distribution uniformity. Among them, the 30% doping amount is slightly better in terms of size reduction and dispersion reduction, but the 10% doping amount still maintains good size uniformity, which is better than the undoped sample.
[0110] The perovskite nanocrystals prepared in Examples 4-6 and Comparative Example 1 were characterized by X-ray diffraction (XRD, Rigaku).
[0111] like Figure 4 As shown, CsPb x La 1-x XRD diffraction peaks appeared at 15.3°, 23.6°, 30.7°, 34.7°, and 37.8°. The relative intensities and positions of these peaks were largely consistent with those of the CsPbBr3 nanocrystal standard card, and almost no other impurity peaks were observed. La-doped... 3+ The diffraction peak intensities of the perovskite nanocrystals were all higher than those of pure CsPbBr3 nanocrystals, indicating that CsPb x La 1-x The crystallinity and crystal quality of Br3 nanocrystals were improved. A magnified view of the XRD peaks shows a shift towards the 2θ value, indicating lattice contraction, which enhances the stability of the crystal structure and thus improves the thermal and chemical stability of the perovskite nanocrystals.
[0112] The PL emission spectra of the perovskite nanocrystals prepared in Examples 4-6 and Comparative Example 1 were determined by fluorescence spectrophotometer.
[0113] like Figure 5 As shown, with La 3+ With increasing doping concentration, the fluorescence emission intensity initially increases and then decreases in La. 3+ The doping concentration reaches a peak at approximately 30%, which is due to the lattice structure change caused by doping. La 3+ The doping leads to local lattice compression and a decrease in the lattice constant, which alleviates the internal stress in the original crystal and reduces the defect states caused by lattice distortion.
[0114] The UV-Vis absorption spectra of the perovskite nanocrystals prepared in Examples 4-6 and Comparative Example 1 were measured using a UV-Vis spectrophotometer.
[0115] like Figure 6 As shown, the absorption peak positions of perovskite nanocrystals with different doping ratios exhibit a certain regularity in the UV-Vis region, with slight shifts in the absorption peaks as the lanthanum ion doping ratio changes. The "absorption enhancement region" (absorption edge) of all curves is concentrated around 450-550 nm, indicating that the optical band gap of the material is basically stable (the band gap determines the absorption edge wavelength), and the variables do not significantly change the band structure of the material.
[0116] The fluorescence properties of the perovskite nanocrystals prepared in Example 4 and Comparative Example 1 were tested after being treated at different temperatures (30℃, 60℃ and 90℃) for 48 h.
[0117] like Figure 7 As shown, in Example 4, La was doped at 30°C, 60°C, and 90°C. 3+ The perovskite nanocrystals always maintain a ratio of 1 to undoped La 3+ The perovskite nanocrystals exhibit higher fluorescence intensity and better stability at different temperatures.
[0118] The X-ray photoelectron spectroscopy (XPS) of the perovskite nanocrystals prepared in Example 4 and Comparative Example 1 was tested.
[0119] like Figure 8 As shown, the peaks in the spectra of Cs3d, Pb4f, and Br3d shift towards higher binding energies, [PbBr6] 4- The chemical environment of the octahedron is changed. After La doping, the Pb–Br interaction is stronger, the lattice shrinks, the lattice constant decreases, the chemical bonds become shorter, the interaction is enhanced, and the thermodynamic stability is improved.
[0120] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer, characterized in that, Includes the following steps: S1. Preparation of perovskite precursor solution and doped ion precursor solution; S2. Inject the perovskite precursor solution, antisolvent, and doped ion precursor solution into the acoustic micromixer through three independent inlets, respectively, and adjust the flow rate of the three independent inlets to a range of 10-2500 μL / min. S3. The microchannel sidewalls of the acoustic micromixer are provided with periodically distributed sharp edge structures and bubble trapping grooves to control the mixing of perovskite precursor solution, antisolvent and doped ion precursor solution in the microchannel, with a mixing time of 1ms≤t≤5ms. S4. Collect the products at the outlet of the acoustic micromixer into a sample bottle to obtain La 3+ doped CsPb x La 1-x Br3 (0.5 < x < 1.0) nanocrystal colloidal solution. After standing, wash and centrifuge to obtain La 3+ doped CsPb x La 1-x Br3 nanocrystals.
2. The method for continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer according to claim 1, characterized in that: In S1, the perovskite precursor solution is prepared by dissolving CsBr, PbBr2, oleylamine and oleic acid in dry dimethylformamide to prepare a perovskite precursor solution with a concentration of 0.03-0.05 mmol / mL for each component.
3. The method for continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer according to claim 1, characterized in that: In S1, the preparation of the doped ion precursor solution involves dissolving LaBr3, oleylamine, and oleic acid in dry dimethylformamide to prepare a doped ion precursor solution with a concentration of 0.03-0.05 mmol / mL for each component.
4. The method for continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer according to claim 1, characterized in that: In S2, the antisolvent is isopropanol, and the volume ratio of the perovskite precursor solution, antisolvent, and doped ion precursor solution injected into the acoustic micromixer is 1:10:m,0. <m≤0.5。 5. The method for continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer according to claim 1, characterized in that: In S2, the acoustic micro-mixer includes a piezoelectric transducer and a microfluidic chip. The piezoelectric transducer is located at the bottom of the microfluidic chip, which includes a microchannel. One end of the microchannel is connected to several independent inlets, and each independent inlet is equipped with a flow control device. The other end of the microchannel is connected to an outlet.
6. The method for continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer according to claim 1, characterized in that: In S2, the flow rate ratio of the perovskite precursor solution to the doped ion precursor solution is 1:0.1-0.
5.
7. The method for continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer according to claim 1, characterized in that: In S3, sharp edge structures are alternately distributed on both sides of the microchannel. The bubble trapping groove is set on one of the side walls of the microchannel. The bubble trapping groove is alternately set with the sharp edge structures on the same side wall and corresponds to the position of the sharp edge structures on the opposite side wall.
8. The method for continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer according to claim 7, characterized in that: In S3, the depth of the microchannel is 100μm, and the width of the main channel of the microchannel is 600μm.
9. The method for continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer according to claim 7, characterized in that: In S3, the distance between the top of the sharp edge structure and the sidewall is 300 μm, the angle of the apex of the sharp edge structure is 15°, and the distance between the apex of two adjacent sharp edge structures on the same sidewall is 600 μm.
10. The method for continuous synthesis of ion-doped perovskite nanocrystals based on an acoustic micromixer according to claim 1, characterized in that: In S3, the mixing temperature is 25-30℃.