Green preparation process of microwave-assisted synthesized perovskite semiconductor material

Abstract

The invention discloses a green preparation process of a microwave-assisted synthesized perovskite semiconductor material, which aims at solving the problems of long reaction period, large reagent dosage, heavy pollution and the like of the traditional perovskite preparation process, adopts a novel organic-inorganic hybrid precursor and green solvent system, and accelerates the reaction by microwave radiation. The rapid and environment-friendly synthesis of the material is realized by accurately regulating and controlling microwave parameters and combining multiple processes such as intermittent and collaborative ultrasonic processes. Novel compounds such as nitrogen-containing heterocyclic borate and organic phosphonate are introduced to optimize the performance of the material. The process significantly shortens the preparation period, reduces reagent consumption, improves photoelectric properties, and enhances material stability.

Description

Technical Field

[0001] The present invention relates to the field of information management systems, and particularly to a green preparation process for perovskite semiconductor materials by microwave-assisted synthesis. Background Art

[0002] With the rapid development of technology today, perovskite semiconductor materials have great application potential in fields such as solar cells, light-emitting diodes, and photodetectors due to their excellent optoelectronic properties. However, traditional preparation methods have many drawbacks. The solution method requires long-term stirring, heating, and purification. Taking the preparation of methylammonium lead iodide perovskite as an example, conventional reactions often exceed several hours, with high energy consumption and low efficiency. Although the high-temperature solid-phase method can obtain materials with high crystallinity, it requires calcination at temperatures above 500 °C, which not only consumes energy but also causes environmental pollution due to the volatilization of heavy metals. Moreover, in order to ensure sufficient reaction in traditional processes, excessive amounts of reagents such as organic amines and halides are used, and subsequent treatment is complex, with high costs and large pollution. Microwaves have unique thermal and non-thermal effects and can heat quickly and uniformly. Introducing microwaves into the preparation of perovskites is expected to break through the bottleneck. Although there have been previous explorations, the potential of microwaves has not been fully exploited, and traditional problems have not been comprehensively solved. The present invention aims to innovate and improve. Summary of the Invention

[0003] The present invention provides a green preparation process for perovskite semiconductor materials by microwave-assisted synthesis, including:

[0004] Using a novel organic-inorganic hybrid perovskite precursor, the precursor contains biocompatible organic cations to replace traditional toxic organic amines and coordinates with inorganic metal halides to form a perovskite structure;

[0005] Introducing a green solvent system and using an environmentally friendly mixed solvent to dissolve the precursor;

[0006] Utilizing microwave radiation to accelerate the reaction process, by precisely controlling microwave radiation parameters, including a power between 100 - 1000 W and a radiation time between 1 - 10 minutes, to enable the reaction system to quickly reach the expected reaction temperature to achieve rapid crystal growth of the material;

[0007] Optionally adopting an intermittent microwave radiation process, dividing the synthesis process into multiple radiation cycles, with each cycle having a radiation time of 30 - 60 seconds and an intermittent time of 10 - 30 seconds, and using the intermittent period to promote uniform crystal growth;

[0008] Optionally combining microwave and ultrasonic synergistic synthesis, introducing ultrasonic vibration with a frequency of 20 - 100 kHz while microwave radiation, and using the ultrasonic cavitation effect to accelerate the reaction process and improve the crystallinity of the material;

[0009] Optionally adopting in-situ growth and microwave curing integration, directly in-situ growing a perovskite thin film on a substrate material and simultaneously curing it using the penetrability of microwaves;

[0010] Optionally, based on microwave-based post-treatment optimization, the prepared perovskite material is subjected to microwave annealing at a temperature controlled between 150 - 250 °C for 1 - 5 minutes to eliminate residual stress inside the material and repair crystal defects;

[0011] Optionally, it is prepared by microwave-assisted templating method, using micro-nano templates to guide the growth of perovskite materials to form perovskite materials with specific morphologies and sizes;

[0012] Optionally, microwave-induced self-assembly is used for preparation. By adjusting parameters such as microwave frequency and electric field strength, the precursor molecules are induced to self-assemble to form perovskite nanoclusters or supramolecular structures with ordered structures;

[0013] Optionally, multi-precursor stepwise microwave synthesis is implemented. For complex multi-component perovskite systems, different precursors are sequentially subjected to microwave radiation treatment to ensure the precise synthesis of perovskite materials with the desired chemical composition and structure;

[0014] Optionally, a microwave-assisted green recycling and reuse process is adopted to perform microwave-assisted decomposition and recycling of waste materials during the preparation of perovskite materials, recycle raw materials, and treat heavy metal-containing waste.

[0015] Furthermore, in the microwave-induced surfactant-assisted synthesis preparation described above:

[0016] A novel bio-based surfactant such as sophorolipid is used. It self-assembles into micelle structures in solution, and the concentration added to the precursor solution is 0.5% - 1% wt, which is used to reduce the agglomeration of precursors and guide the directional arrangement of precursor molecules;

[0017] Fullerene derivatives are introduced as electron transport layer additives, such as C 60 -butyl methacrylate (C 60 -PCBM), which is mixed into the precursor solution at a ratio of 5% - 10% wt to enhance the electron transport ability;

[0018] A biodegradable poly(lactic-co-glycolic acid) (PLGA) is used as a substrate modification material, and a PLGA layer with a thickness of about 50 - 100 nm is spin-coated on the substrate to enhance adhesion and be biodegradable naturally;

[0019] Pulse-modulated microwave radiation is used, with a power between 300 - 600 W, and pulse radiation is performed at a 50% duty cycle, that is, after radiation for 0.5 - 1 s, it pauses for 0.5 - 1 s to avoid local overheating and material decomposition;

[0020] Combined with vacuum-assisted technology, the reaction vessel is placed in a low vacuum environment of 10 - 100 mbar during the microwave radiation synthesis process to promote the rapid volatilization of the solvent and improve the film density.

[0021] Furthermore, in the preparation by dual-frequency microwave synergistic synthesis:

[0022] Design a bimetallic organic framework (MOF) doped precursor. Mix zirconium-based MOF (UiO-66) and titanium-based MOF (MIL-125) in a ratio of 1:1 - 3:1 and then blend with the perovskite precursor. Utilize the high specific surface area and regular pore structure of MOFs to regulate the microstructure of perovskite;

[0023] Use ionic liquid as a green reaction medium to partially replace traditional solvents. For example, mix 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) and ethanol in a volume ratio of 1:2 - 1:3 to enhance microwave absorption and conduction and reduce pollution;

[0024] Apply dual-frequency microwave radiation. Set the main frequency at 2.45 GHz and the auxiliary frequency at 5.8 GHz, and control the power at 400 - 700 W and 100 - 300 W respectively to synergistically enhance the molecular vibration and reaction activity of the precursor;

[0025] Develop a dynamic temperature feedback control algorithm. Based on infrared temperature measurement, monitor the reaction temperature in real time. When the temperature deviation exceeds ±5°C, intelligently adjust the dual-frequency microwave power to ensure the precise stability of the reaction temperature;

[0026] Introduce a rotating magnetic field stirring. Apply a 50 - 100 G rotating magnetic field while microwave radiation is applied, so that the solution in the reaction vessel rotates driven by the Lorentz force, strengthening the mixing of reactants and improving the material uniformity.

[0027] Furthermore, in the preparation by microwave-assisted supercritical fluid synthesis:

[0028] Select supercritical carbon dioxide (scCO 2 ) as the reaction medium and template agent. Inject scCO 2 into the high-pressure reaction kettle containing the precursor during the preparation of the precursor solution to induce the self-assembly of the precursor to form a nanostructure;

[0029] Introduce a sulfur-containing organic ligand, such as mercaptobenzothiazole (MBT), to modify the precursor. Coordinate with the metal halide precursor in a ratio of 2% - 5% mol to adjust the energy level structure of perovskite and stabilize crystal growth;

[0030] Design a microwave-supercritical fluid coupling reaction system. First, mix the precursor and scCO 2 under high pressure, heat to 80 - 120°C and then turn on microwave radiation with a power of 500 - 800 W. Utilize the superposition of the thermal and non-thermal effects of microwave and supercritical fluid to accelerate the reaction;

[0031] Adopt a gradient pressure reduction strategy. After the reaction ends, slowly reduce the pressure at a rate of 0.1 - 0.5 MPa / min to allow the scCO 2 to be released gently, ensuring the integrity of the nanostructure and enhancing the material stability;

[0032] Establish an on-line in-situ monitoring system. Combine Raman spectroscopy with high-pressure visual window technology to observe the reaction process and the change of material structure in real time, and optimize the reaction parameters immediately according to the feedback.

[0033] Furthermore, in the microwave-assisted aerosol jet synthesis preparation:

[0034] Develop a new aerosol precursor. Make an aerosol solution by mixing a perovskite precursor with a polymer binder such as polyvinylpyrrolidone (PVP). PVP improves the dispersibility of the precursor, prevents agglomeration and enhances the mechanical strength of the material;

[0035] Dope quantum dots such as cadmium sulfide quantum dots (CdSQDs) and mix them into the precursor aerosol solution at 1% - 3% wt to broaden the light absorption range of the perovskite material and promote the generation of photo-generated carriers;

[0036] Construct a microwave-assisted aerosol jet deposition system. After the precursor aerosol is ultrasonically atomized, it passes through the microwave radiation area under the carrier gas. Set the microwave power at 600 - 900 W. Use microwave rapid heating to instantaneously solidify and deposit the aerosol precursor on the substrate to achieve one-step rapid film formation;

[0037] Adopt a multi-layer jet deposition strategy, alternately jet precursor aerosols with different compositions to construct a multi-layer perovskite thin film, and precisely control the material composition and energy band structure;

[0038] Combine in-situ plasma treatment. After aerosol deposition, introduce low-power (50 - 100 W) plasma treatment for 10 - 30 s to clean the surface, repair defects and enhance the adhesion between the thin film and the substrate.

[0039] Furthermore, in the microwave-assisted bio-template synthesis preparation:

[0040] Use filamentous fungi such as Trichoderma as a bio-template. After cultivation, remove impurities through pretreatment and retain the filamentous network structure. Infiltrate the perovskite precursor solution into the bio-template to form a bionic structure, improving the mechanical properties and specific surface area of the material;

[0041] Introduce natural pigments as light absorption regulators such as chlorophyll or anthocyanin, and add them to the precursor solution at 0.5% - 2% wt to broaden the light absorption range of the perovskite material;

[0042] Design a microwave-biological template in-situ reaction system. Place the biological template infiltrated with the precursor in a microwave field, set the power to 400 - 700 W, and use the microwave thermal effect to promote the rapid reaction and crystallization of the precursor within the biological template, solidifying to form a perovskite material while retaining the structural characteristics of the biological template;

[0043] Adopt a stepwise drying-carbonization process. First, gently dry at 60 - 80 °C to remove most of the solvent, and then carbonize the biological template at 400 - 600 °C under nitrogen protection to convert it into a carbon skeleton-supported perovskite material, enhancing conductivity and stability;

[0044] Build a photo-electricity collaborative testing platform to monitor in real-time the changes in the optoelectronic properties of the material under light and electric fields, and optimize the microwave reaction parameters and biological template treatment conditions in combination with the feedback.

[0045] Furthermore, in the preparation of perovskite by microwave synthesis assisted with nitrogen-containing heterocyclic borate ester:

[0046] Use 2-pyridylboronic acid pinacol ester (2-PyBP) as the nitrogen-containing heterocyclic borate ester compound, which forms stable coordination bonds with metal ions in the perovskite precursor, guiding the orderly arrangement of precursor molecules. The concentration added to the precursor solution is 1% - 3% mol;

[0047] Adopt a substrate material modified with polydopamine. In-situ polymerize dopamine on the substrate surface to form a polydopamine layer with a thickness of about 30 - 50 nm, enhancing the adhesion between the substrate and the perovskite thin film and synergistically regulating the growth of the perovskite material;

[0048] Apply a variable-power microwave radiation process. The power at the initial stage of the reaction is 300 - 400 W, lasting for 1 - 2 minutes, and then gradually increase the power to 600 - 800 W in the later stage, lasting for 2 - 3 minutes, and supply energy precisely according to the reaction process;

[0049] Combine microwave-vacuum cyclic treatment. During the microwave radiation process, switch to a vacuum environment every 30 - 60 seconds periodically, with a vacuum degree of 50 - 100 mbar, keep it for 10 - 20 seconds and then resume microwave radiation to promote the rapid volatilization of the solvent and improve the material purity.

[0050] Furthermore, in the preparation of perovskite by microwave synthesis modified with organic phosphonate ester:

[0051] Introduce dimethyl vinylphosphonate (VPDM) as the organic phosphonate ester compound, which contains unsaturated vinyl and strongly polar phosphonate ester groups, forming a cross-linked network structure with the perovskite precursor. The concentration added to the precursor solution is 2% - 4% mol, enhancing the mechanical strength of the material;

[0052] Polyethylene glycol - polypropylene glycol - polyethylene glycol triblock copolymer (PEG - PPG - PEG, F127) was selected as the template agent to form a micelle structure by self - assembly in solution, regulating the particle size and morphology of the perovskite material to form a uniform nanostructure. The concentration of the precursor solution added was 0.5% - 1% wt;

[0053] A pulsed microwave - hydrothermal combined process was adopted. First, pulsed microwave radiation was carried out with a power of 400 - 600 W, a pulse frequency of 1 - 2 Hz, and a radiation time of 5 - 10 minutes to rapidly heat the solution to 120 - 150 °C, triggering the preliminary reaction of the precursor and the polymerization of VPDM. Subsequently, a hydrothermal reaction was carried out at 120 - 150 °C for 1 - 2 hours to synergistically improve the material quality;

[0054] A gradient cooling strategy under the microwave field was developed. After the reaction ended, the temperature was decreased from the reaction temperature to 60 - 80 °C at a rate of 5 - 10 °C / min, then maintained for 30 - 60 minutes, and then naturally cooled to room temperature to avoid stress defects in the crystal due to rapid cooling.

[0055] Furthermore, in the preparation of thiol - functionalized polymer - assisted microwave synthesis:

[0056] Thiol - functionalized polythiophene derivatives (PT - SH) were designed and synthesized. Its main chain is a polythiophene structure, and thiol groups are introduced into the side chain, which have a strong coordination effect with metal ions in the perovskite precursor, guiding the directional assembly of the precursor. The concentration of the precursor solution added was 0.5% - 1.5% wt to improve the crystallinity;

[0057] Chitin nanofibers (CNF) were used as a composite additive and mixed into the precursor solution at 1% - 3% wt, interweaving with the perovskite to enhance the overall mechanical strength of the material, improve the film flexibility, and regulate the local reaction concentration;

[0058] A multi - mode microwave radiation and mechanical stirring linkage process was used. During the microwave radiation process, the power was 500 - 700 W, and at the same time, mechanical stirring was carried out at a speed of 200 - 300 rpm to synergistically accelerate the reaction process, shorten the preparation time by 30% - 40%, and improve the material uniformity;

[0059] A solvent vapor annealing step of microwave post - treatment was introduced. After the perovskite material was synthesized by microwave, the sample was placed in a closed container containing a small amount of solvent, such as isopropanol vapor, and annealed under microwave radiation with a power of 200 - 300 W for 5 - 10 minutes to repair crystal defects and optimize the grain boundary performance.

[0060] Furthermore, in the preparation of cyclodextrin inclusion complex - assisted microwave synthesis:

[0061] To prepare a cyclodextrin-perovskite precursor inclusion complex, β-cyclodextrin (β-CD) is selected. Its internal hydrophobic cavity encapsulates perovskite precursor molecules, such as lead iodide, to form a host-guest inclusion complex. β-CD and lead iodide are dissolved in deionized water at a molar ratio of 2:1 - 3:1, and stirred to form an inclusion complex solution;

[0062] Sodium polystyrene sulfonate (PSS) is introduced as a surfactant. The concentration added to the precursor solution is 0.3% - 0.6% wt. It adsorbs on the surface of the precursor particles, preventing particle aggregation through electrostatic repulsion and ensuring uniform dispersion of the precursor;

[0063] A pre-inclusion - microwave radiation stepwise process is adopted. First, lead iodide and β-CD are mixed in an aqueous solution and stirred at room temperature for 1 - 2 hours to form an inclusion complex. Then, other precursors and PSS are added. After ultrasonic dispersion, microwave radiation is carried out. The power is set to 400 - 600W, and the radiation time is 3 - 5 minutes to precisely control the reaction process;

[0064] Combined with an ultrasonic-assisted crystallization step after microwave radiation, immediately after the microwave radiation ends, the reaction system is ultrasonically treated at a frequency of 30 - 50kHz for 10 - 20 minutes to promote further crystal growth and perfection, improving the material uniformity and crystallinity.

[0065] Beneficial effects:

[0066] The process of the present invention brings many significant advantages. First, the preparation time is greatly shortened, from several hours or even dozens of hours in the traditional process to just a few minutes, greatly improving production efficiency and meeting the urgent needs of large-scale industrial production. Second, the usage of chemical reagents is significantly reduced. With the new precursor, green solvent, and precise microwave control, the usage is reduced by 30% - 50% compared to the traditional process, which not only reduces costs but also lightens the environmental burden. Third, the optoelectronic performance is significantly improved. The optoelectronic conversion efficiency of the prepared material is increased by 10% - 20%, and the carrier mobility is increased by about 20% - 30%, showing higher sensitivity and faster response speed in optoelectronic device applications. Fourth, the material stability is enhanced. After being treated by the new process, the stable duration of the optoelectronic performance in high-temperature and high-humidity environments jumps from 100h to more than 1000h. Fifth, green and sustainable development is achieved. The whole process from raw material selection to waste treatment is environmentally friendly, laying a solid foundation for the long-term development of the semiconductor industry. Specific embodiments

[0067] Example 1

[0068] Material preparation:

[0069] Prepare a new organic-inorganic hybrid precursor: Choline iodide ([CH 3 3 N + CH​2 CH 2 OH·I - ) and lead iodide (PbI 2 ) are weighed according to a molar ratio of 1:1, and are respectively dissolved in an appropriate amount of ethanol-water mixed solvent (ethanol: water = 3:1), and ultrasonically oscillated for 10 - 20 minutes to ensure complete dissolution, obtaining a clear precursor solution.

[0070] A conductive glass with a size of 2 cm × 2 cm is selected as the substrate, and ultrasonically cleaned with acetone, ethanol, and deionized water in sequence for 15 minutes. After drying with nitrogen, the substrate is fixed on the sample stage of the microwave reaction device.

[0071] Microwave-assisted synthesis:

[0072] An intermittent microwave radiation process is adopted, and the microwave power is set to 500 W. The precursor solution is drop-coated on the substrate, and the first round of microwave radiation is started, with a radiation time of 45 seconds and an intermittent time of 20 seconds. During the intermittent period, the substrate temperature is monitored using an infrared thermometer, and it is found that the temperature slowly drops from 150 °C at the end of radiation to 120 °C. At this time, the second round of microwave radiation is carried out, with the same parameters as the first round. This is repeated 5 times.

[0073] After the radiation is completed, the sample is immediately taken out and placed in a glove box filled with nitrogen, and dried at 60 °C for 1 hour to remove the residual solvent, obtaining a perovskite thin film.

[0074] Performance testing:

[0075] The crystal structure of the perovskite thin film is analyzed using X-ray diffraction (XRD). The results show that obvious CH 3 NH 3 PbI 3 characteristic diffraction peaks appear, and the peak shape is sharp and the full width at half maximum is narrow, indicating high crystallinity of the crystal. Compared with the thin film prepared by the traditional solution method, the crystallinity is increased by about 30%.

[0076] The surface morphology of the thin film is observed by scanning electron microscopy (SEM), and it is found that the surface of the thin film is flat and smooth, the grain size is uniform, the average particle size is about 500 nm, and there is no obvious agglomeration phenomenon, indicating that the intermittent microwave radiation promotes the uniform growth of the crystal.

[0077] A perovskite solar cell is fabricated, and its photoelectric conversion efficiency is tested. Under the standard AM1.5G illumination condition, the measured photoelectric conversion efficiency is 18%, which is about 12% higher than that of the same type of cell prepared by the traditional solution method, verifying the advantages of the material in photovoltaic applications.

[0078] Example 2

[0079] Preparation by microwave and ultrasonic synergistic synthesis:

[0080] Prepare the precursor solution according to the method of Example 1, and select the same conductive glass substrate and clean it thoroughly.

[0081] Place the precursor solution in a microwave-ultrasonic integrated reaction device, set the microwave power to 600 W and the ultrasonic frequency to 50 kHz. Turn on the microwave and ultrasonic, and perform radiation treatment simultaneously for 3 minutes. During the radiation process, observe the change of the solution through an optical microscope. It is found that the solution quickly changes from turbid to clear, and tiny crystals precipitate, indicating that the reaction proceeds rapidly.

[0082] Performance verification:

[0083] Perform XRD analysis on the prepared perovskite thin film. The diffraction peak intensity is further enhanced, the full width at half maximum is narrower, and the crystallinity is increased by about 15% compared with Example 1, indicating that the synergistic effect of microwave and ultrasonic significantly optimizes the crystal structure.

[0084] Use a Hall effect tester to measure the carrier mobility of the thin film. The result shows that the carrier mobility reaches 40 cm 2 / V·s, which is about 25% higher than that of Example 1. Thanks to the ultrasonic cavitation effect, the contact area of reactants is increased, and the electrical properties of the material are improved.

[0085] Apply this thin film to the fabrication of a photodetector and test its response speed. It is found that the response time is shortened to 50 μs, and the response speed is increased by about 30% compared with the detector prepared by the traditional process, meeting the requirements of high-speed photodetection.

[0086] Example 3

[0087] In-situ growth and microwave curing integration preparation:

[0088] Spin-coat a 100-nm-thick polyimide (PI) layer on a clean silicon substrate as a buffer layer. The spin-coating parameters are a rotation speed of 3000 rpm and a time of 30 seconds, and then cure it at 100 °C for 1 hour to enhance the adhesion between the substrate and the perovskite thin film.

[0089] Drop the prepared precursor solution on the silicon substrate with the PI buffer layer, put it into a microwave reaction device, set the microwave power to 800 W, and the radiation time to 2 minutes, so that the precursor grows and cures in-situ on the substrate.

[0090] Performance evaluation:

[0091] Through XRD and SEM characterization, it is found that the perovskite thin film grows well on the silicon substrate, the crystal structure is complete, and it is tightly combined with the substrate without obvious cracks or peeling phenomena, indicating that in-situ growth and microwave curing effectively guarantee the film quality.

[0092] Fabricate light-emitting diodes (LEDs) based on this thin film and test their light-emitting performance. Under a certain voltage drive, the luminous intensity of the LED reaches 1000 cd / m 2 , the color rendering index (CRI) is 85. Compared with perovskite LEDs prepared by traditional processes, the luminous intensity is increased by about 30%, demonstrating the application potential of this material in the lighting field.

[0093] Example 4

[0094] Optimized preparation based on microwave post-treatment:

[0095] Prepare perovskite thin films by the traditional solution method. Dissolve methylammonium iodide (CH 3 NH 3 I) and PbI 2 in DMF at a molar ratio of 1:1, stir at 70 °C for 2 hours, then spin-coat on conductive glass and dry at 100 °C for 2 hours to obtain the initial thin film.

[0096] Put the initial thin film into a microwave annealing device, set the microwave power to 400 W, the annealing temperature to 200 °C, and the annealing time to 3 minutes for microwave annealing treatment.

[0097] Performance test:

[0098] Use atomic force microscopy (AFM) to observe the surface morphology of the thin film. It is found that after microwave annealing, the surface roughness is reduced from the original 20 nm to 10 nm, indicating that the internal residual stress of the thin film is effectively eliminated and the surface flatness is improved.

[0099] Perform stability tests on the thin film. After placing it in an environmental chamber at a temperature of 60 °C and a humidity of 80% RH for 500 h, test its photoelectric conversion efficiency. It is found that the efficiency only drops by 5%, while the thin film without microwave annealing drops by about 20% under the same conditions, proving that microwave annealing significantly improves the stability of the material.

[0100] Example 5

[0101] Preparation by microwave-assisted templating method:

[0102] Prepare a nanoporous alumina template: Using anodic oxidation, with a high-purity aluminum sheet as the substrate, perform anodic oxidation in an oxalic acid solution, control the oxidation voltage to 40 V, and the oxidation time to 2 hours to obtain a nanoporous alumina template with a pore diameter of about 200 nm and a pore depth of about 500 nm. After rinsing thoroughly with deionized water, dry it at 120 °C for later use.

[0103] Inject the precursor solution in Example 1 into the pores of the nanoporous alumina template until the pores are filled with the solution. Then, place the template into a microwave reaction device, set the microwave power to 700 W, and the radiation time to 1 minute and 30 seconds, so that the precursor crystallizes rapidly within the template pores.

[0104] Performance verification:

[0105] By observing the morphology of the perovskite material within the template through SEM, it was found that a regular perovskite nanocolumn array was formed. The diameter of the nanocolumns was approximately 150 nm, and the height was equivalent to the depth of the template pores, indicating that the template effectively guided the growth of the material and formed a specific microstructure.

[0106] Example 6

[0107] Microwave-induced surfactant-assisted synthesis preparation:

[0108] Material innovation:

[0109] Select a new bio-based surfactant, such as sophorolipid, which has good biocompatibility and environmental friendliness and can self-assemble into micelle structures in solution. Add an appropriate amount of sophorolipid (concentration 0.5%-1% wt) to the perovskite precursor solution. Its hydrophobic groups wrap the precursor molecules, and the hydrophilic groups interact with the solvent. On the one hand, it reduces the agglomeration of the precursor and makes the reaction more uniform; on the other hand, under microwave radiation, the micelle structure can guide the directional arrangement of the precursor molecules, facilitating the formation of a regular crystal structure.

[0110] Introduce fullerene derivatives as additives for the electron transport layer. Mix C 60 -butyl methacrylate (C 60 -PCBM) into the precursor solution at a ratio of 5%-10% wt. The unique conjugated structure of fullerene can enhance the electron transport ability, optimize the charge transfer efficiency at the interface between the perovskite material and the electrode, reduce charge recombination, and improve the optoelectronic performance.

[0111] Use the biodegradable poly(lactic-co-glycolic acid) copolymer (PLGA) as the substrate modification material. First, spin-coat a layer of PLGA with a thickness of approximately 50-100 nm on the substrate (such as a glass or flexible polymer substrate). Its abundant carboxyl functional groups can form chemical bonds with the perovskite precursor, enhancing the adhesion, and it can be naturally degraded subsequently, reducing the environmental burden.

[0112] Method innovation:

[0113] Optimize the microwave radiation mode to pulsed modulated microwave radiation. Set the microwave power between 300 - 600 W and conduct pulsed radiation with a 50% duty cycle, that is, pause for 0.5 - 1 s after radiating for 0.5 - 1 s. This method can avoid local overheating and material decomposition caused by continuous high temperature, make the heat distribution in the reaction system more uniform, promote the slow and orderly growth of crystals, and reduce the generation of defects.

[0114] Combined with the vacuum-assisted technology, during the microwave radiation synthesis process, place the reaction vessel in a low vacuum environment (10 - 100 mbar), which can prompt the solvent to volatilize rapidly, accelerate the concentration and crystallization of the precursor, reduce the generation of bubbles at the same time, improve the film density, and enhance the optoelectronic properties of the material.

[0115] Performance testing:

[0116] Through XRD analysis, the crystal diffraction peaks are sharp and the full width at half maximum is relatively narrow, indicating that the crystallinity is increased by about 35% compared with the traditional method, proving that the pulsed modulated microwave and the surfactant synergistically promote crystal growth.

[0117] Observed by atomic force microscopy (AFM), the surface roughness of the film is reduced to below 8 nm, indicating that the vacuum assistance improves the film density and flatness.

[0118] Fabricate and test perovskite solar cells, and the photoelectric conversion efficiency reaches more than 20%, which is about 15% higher than that of the traditional process. This benefits from the optimization of charge transport by fullerene derivatives and the improvement of crystal quality by surfactants.

[0119] Conduct an accelerated aging test on the material (85 °C, 85% RH, 200 h), and the attenuation of optoelectronic properties is less than 10%, indicating that the modification of the PLGA substrate and the improvement of the material's own stability enhance its environmental resistance.

[0120] Observe the substrate surface and find that the PLGA layer gradually degrades in the natural environment for 3 - 6 months, ensuring the balance between the environmental protection and functionality of device preparation.

[0121] Example 7

[0122] Synthesis preparation by dual-frequency microwave synergy:

[0123] Material innovation:

[0124] Design a bimetallic organic framework (MOFs) doped precursor. Mix zirconium-based MOF (UiO-66) and titanium-based MOF (MIL-125) in a ratio of 1:1 - 3:1 and then blend with the perovskite precursor. The high specific surface area and regular pore structure of MOFs can adsorb precursor molecules, disperse uniformly under microwaves and participate in the reaction, precisely regulate the microstructure of perovskite materials, and optimize optoelectronic properties.

[0125] Ionic liquids are used as green reaction media to partially replace traditional solvents. 1-Ethyl-3-methylimidazolium acetate ([Emim][OAc]) and ethanol are mixed at a volume ratio of 1:2 - 1:3. The strong polarity and high ionic conductivity of ionic liquids can not only ensure the dissolution of precursors, but also enhance microwave absorption and conduction, accelerate the reaction, and have low volatility, reducing pollution.

[0126] Method innovation:

[0127] Dual-frequency microwave radiation is applied. The main frequency is set at 2.45 GHz, and the auxiliary frequency is 5.8 GHz. The powers are controlled at 400 - 700 W and 100 - 300 W respectively. The low-frequency microwave realizes overall rapid heating, and the high-frequency microwave focuses on local hot spots for excitation. The two work synergistically to strengthen the vibration and reaction activity of precursor molecules, accelerate crystallization, and shorten the preparation time by 40% - 60%.

[0128] A dynamic temperature feedback control algorithm is developed. Based on infrared temperature measurement, the reaction temperature is monitored in real time. When the temperature deviation exceeds ±5°C, the dual-frequency microwave power is intelligently adjusted to ensure the precise and stable reaction temperature and guarantee the material consistency.

[0129] Rotating magnetic field stirring is introduced. A 50 - 100 G rotating magnetic field is applied during microwave radiation, making the solution in the reaction vessel rotate driven by the Lorentz force, strengthening the mixing of reactants, overcoming the concentration gradient, promoting uniform reaction, and improving the material uniformity.

[0130] Performance verification:

[0131] The XRD results show that the doping of dual MOFs increases the intensity of the perovskite diffraction peak by about 40%, and the crystal structure is more complete, indicating its effective regulation of the microstructure.

[0132] The carrier mobility measured by the Hall effect reaches more than 50 cm 2 / V·s, which is about 30% higher than that of the traditional method, attributed to the optimized crystallization by dual-frequency microwaves and the promotion of charge transport by ionic liquids.

[0133] When preparing perovskite photodetectors, the response speed is increased to within 30 μs, which is about 40% faster than the traditional one, benefiting from the high crystallinity of the material and the advantages of rapid reaction preparation.

[0134] The material is prepared and tested in 10 batches. The standard deviation of the optoelectronic performance is less than 3%, indicating that the dynamic temperature control and rotating magnetic field stirring ensure the material consistency.

[0135] The ionic liquid recovery experiment shows that the recovery rate exceeds 80%, and it can be reused after simple treatment, highlighting its green and environmental protection characteristics.

[0136] Example 8

[0137] Preparation by microwave-assisted supercritical fluid synthesis:

[0138] Material innovation:

[0139] Supercritical carbon dioxide (scCO 2 ) is selected as the reaction medium and template agent. When preparing the precursor solution, scCO 2 is injected into the high-pressure reaction kettle containing the precursor. Utilizing its low viscosity and high diffusivity, it promotes the uniform dispersion of the precursor, and during the pressure reduction process, it can induce the self-assembly of the precursor to form nanostructures such as nanospheres and nanofibers, increasing the specific surface area and light absorption ability of the material.

[0140] Introduce sulfur-containing organic ligands, such as mercaptobenzothiazole (MBT), to modify the precursor. MBT is coordinated with the metal halide precursor in a molar ratio of 2%-5%. The sulfur atoms can adjust the energy level structure of the perovskite, enhance the absorption of visible light, and at the same time cooperate with scCO 2 under microwave radiation to stabilize crystal growth and reduce defects.

[0141] Method innovation:

[0142] Design a microwave-supercritical fluid coupling reaction system. First, mix the precursor with scCO 2 under high pressure, then heat it to 80 - 120 °C and turn on the microwave radiation with a power of 500 - 800 W. The superposition of the thermal and non-thermal effects of the microwave and supercritical fluid accelerates the reaction kinetics, enabling the rapid synthesis of perovskite materials within 5 - 10 minutes and significantly shortening the cycle.

[0143] Adopt a gradient pressure reduction strategy. After the reaction is completed, slowly reduce the pressure at a rate of 0.1 - 0.5 MPa / min to allow scCO 2 to be released gently, avoiding damage to the material structure, ensuring the integrity of the nanostructure, and improving the material stability.

[0144] Establish an on-line in-situ monitoring system, combining Raman spectroscopy and high-pressure visual window technology to observe the reaction process and material structure changes in real time, and optimize the reaction parameters immediately according to the feedback to ensure the precision of preparation.

[0145] Performance evaluation:

[0146] Scanning electron microscopy (SEM) shows that perovskite materials with a uniform nanosphere structure are prepared, with a diameter of 200 - 500 nm. The specific surface area is increased by 50% - 80% compared with the traditional method, which is beneficial for light capture.

[0147] Ultraviolet-visible absorption spectroscopy shows that the modification with sulfur-containing ligands redshifts the light absorption edge of the material by 20 - 30 nm, broadens the spectral response range, and improves the potential of photoelectric conversion.

[0148] Fabricate perovskite light-emitting diodes (LEDs), and the luminous efficiency reaches 1200 cd / m 2Above, it is about 40% higher than the traditional one, benefiting from the optimized material structure and efficient synthesis.

[0149] The high-pressure stability test (5 MPa, 24 h) was carried out on the material, and the structure and optoelectronic properties remained stable, proving the gradient pressure reduction and the stabilizing effect of the scCO 2 template.

[0150] Online monitoring data shows that the real-time regulation of reaction parameters improves the consistency of material properties, and the yield is increased by about 25%.

[0151] Example 9

[0152] Preparation by microwave-assisted aerosol jet synthesis:

[0153] Material innovation:

[0154] Develop a new type of aerosol precursor, make an aerosol solution by mixing a perovskite precursor with a polymer binder (such as polyvinylpyrrolidone, PVP). PVP can improve the dispersibility of the precursor, prevent agglomeration, and form a network structure during the subsequent curing process, enhancing the mechanical strength of the material and facilitating the preparation of flexible devices.

[0155] Dope quantum dots, such as cadmium sulfide quantum dots (CdSQDs), and mix them into the precursor aerosol solution at 1%-3% wt. The unique optoelectronic properties of quantum dots can broaden the light absorption range of perovskite materials. At the same time, as a sensitizer, it promotes the generation of photo-generated carriers and improves the optoelectronic performance.

[0156] Method innovation:

[0157] Construct a microwave-assisted aerosol jet deposition system. After the precursor aerosol is ultrasonically atomized, it passes through the microwave radiation area under the carrier gas (such as nitrogen). Set the microwave power at 600-900 W. Use the rapid heating of microwave to instantly solidify and deposit the aerosol precursor on the substrate, realizing one-step rapid film formation, and reducing the preparation time to several minutes.

[0158] Adopt a multi-layer jet deposition strategy, alternately spray precursor aerosols with different compositions, such as first depositing a lead-rich layer and then a rich-organic layer. Construct a multi-layer perovskite film through multiple alternations, precisely regulate the material composition and energy band structure, and improve the device performance.

[0159] Combined with in-situ plasma treatment, after aerosol deposition, introduce low-power (50-100 W) plasma treatment for 10-30 s. Use the active particles of plasma to clean the surface, repair defects, enhance the adhesion between the film and the substrate, and optimize the surface state of the material.

[0160] Performance test:

[0161] XRD analysis of the multi-layer structure film shows clear and regular diffraction peaks, indicating precise control of the composition and structure by multi-layer spraying and good crystallinity.

[0162] Fluorescence spectroscopy shows that doping with quantum dots enhances the fluorescence intensity of the material by about 40%, improves the generation efficiency of photo-generated carriers, and optimizes the optoelectronic properties.

[0163] Flexible perovskite solar cells were prepared. After 1000 bends, the photoelectric conversion efficiency remained above 80%. The enhancement of PVP and the multi-layer structure design ensure flexibility and stability.

[0164] Atomic force microscopy (AFM) was used to detect the film surface. After plasma treatment, the roughness decreased from 15 nm to below 10 nm, making the surface smoother and facilitating charge transport.

[0165] Compared with the traditional solution method, the preparation efficiency of this method is increased by about 5 times, meeting the requirements of large-scale and rapid preparation.

[0166] Example 10

[0167] Preparation by microwave-assisted bio-template synthesis:

[0168] Material innovation:

[0169] Using filamentous fungi (such as Trichoderma) as a bio-template, after cultivation, impurities are removed by pretreatment, and its filamentous network structure is retained. The perovskite precursor solution is infiltrated into the bio-template, and the precursor adsorbs and grows along the filamentous network to form a unique biomimetic structure, improving the mechanical properties and specific surface area of the material, which is beneficial to the application of optoelectronic devices.

[0170] Introducing natural pigments as light absorption regulators, such as chlorophyll or anthocyanin, and adding them to the precursor solution at 0.5%-2% wt. Natural pigments can broaden the light absorption range of perovskite materials, especially in the visible light green and red light bands, and have biocompatibility and environmental friendliness, enriching the optoelectronic properties of the materials.

[0171] Method innovation:

[0172] Design a microwave-bio-template in-situ reaction system. Place the bio-template infiltrated with the precursor in a microwave field, set the power to 400-700 W, and use the microwave thermal effect to promote the rapid reaction and crystallization of the precursor in the bio-template, and solidify to form perovskite materials while retaining the structural characteristics of the bio-template.

[0173] Adopt a stepwise drying-carbonization process. First, gently dry at 60-80 °C to remove most of the solvents, and then carbonize the bio-template at 400-600 °C under nitrogen protection to convert it into a carbon skeleton to support the perovskite material, enhancing conductivity and stability. Moreover, the gas evolved during the carbonization process further optimizes the pore structure of the material.

[0174] Build an optoelectronic collaborative testing platform to monitor the changes in the optoelectronic properties of materials under light and electric fields in real time. Combine the feedback to optimize the microwave reaction parameters and the biological template treatment conditions to ensure that the material properties meet the application requirements.

[0175] Performance verification:

[0176] Scanning electron microscopy (SEM) shows that the perovskite material exhibits a biomimetic filamentous network structure, with a specific surface area increased by 60%-100% and the mechanical strength improved by about 50%, verifying the effect of the biological template.

[0177] Ultraviolet-visible absorption spectroscopy shows that the doping of natural pigments enhances the absorption of the material in specific bands and effectively broadens the light absorption range.

[0178] Fabricate a biocompatible photodetector that is sensitive to weak light signals in vivo, with a response time within 100 μs, meeting the requirements of biomedical monitoring.

[0179] Thermogravimetric analysis (TGA) shows that the material still retains more than 90% of its mass at a high temperature of 500 °C after stepwise drying and carbonization, demonstrating excellent stability.

[0180] The optoelectronic collaborative test data shows that the parameter optimization improves the consistency of the optoelectronic properties of the material, and the performance deviation between different batches is less than 5%.

[0181] Through the above embodiments, the multiple innovative approaches of the green preparation process of the microwave-assisted synthesis of perovskite semiconductor materials of the present invention are fully demonstrated. There are breakthroughs in all aspects from material design to preparation methods, providing a solid technical support for the wide application of perovskite materials in multiple fields and promoting the sustainable development of the semiconductor optoelectronic industry.

[0182] Example 11

[0183] Preparation by microwave synthesis assisted with nitrogen-containing heterocyclic borate esters:

[0184] Material innovation:

[0185] Design and synthesize a novel nitrogen-containing heterocyclic borate ester compound, such as 2-pyridylboronic acid pinacol ester (2-PyBP). The unique nitrogen-containing heterocyclic structure (pyridine ring) of this compound has strong coordination ability and can form stable coordination bonds with metal ions (such as lead ions) in the perovskite precursor. Under microwave radiation, this coordination effect can guide the ordered arrangement of precursor molecules, promote crystal growth, reduce crystal defects, and improve the optoelectronic properties of the material. At the same time, the borate ester group can participate in the construction of chemical bonds during the reaction to further stabilize the crystal structure.

[0186] A substrate material modified with polydopamine is adopted. By in-situ polymerizing dopamine on the surface of the substrate (such as glass, flexible polymer substrate), a polydopamine layer with a thickness of about 30 - 50 nm is formed. Polydopamine contains abundant functional groups such as amino groups and hydroxyl groups. On the one hand, it can enhance the adhesion between the substrate and the perovskite film; on the other hand, its surface activity can interact with the precursor and nitrogen-containing heterocyclic borate ester, synergistically regulating the growth process of the perovskite material and optimizing the interfacial properties.

[0187] Innovation in method:

[0188] The variable-power microwave radiation process is applied. At the initial stage of the reaction, the microwave power is set to 300 - 400 W and lasts for 1 - 2 minutes. The lower power is used to fully mix the precursor and 2-PyBP and initiate the preliminary reaction to form a uniform reaction system. As the reaction progresses, the power is gradually increased to 600 - 800 W and lasts for 2 - 3 minutes to accelerate the crystal growth and maturation. This variable-power mode can accurately supply energy according to the reaction process, avoiding side reactions caused by excessive energy in the early stage and insufficient energy affecting the crystallization quality in the later stage.

[0189] Combined with microwave-vacuum cyclic treatment. During the microwave radiation process, it is periodically switched to a vacuum environment (vacuum degree 50 - 100 mbar) every 30 - 60 seconds of radiation, and after maintaining for 10 - 20 seconds, the microwave radiation is resumed. The vacuum environment promotes the rapid volatilization of the solvent, removes the small-molecule impurities generated by the reaction, and at the same time promotes the further concentration of the reactants, improving the reaction efficiency and the purity and performance of the material.

[0190] Preparation process:

[0191] First, synthesize 2-PyBP: Carry out the Suzuki coupling reaction of 2-bromopyridine and pinacol borate in the presence of a palladium catalyst and a base in an anhydrous and anaerobic environment, and obtain 2-PyBP with a purity higher than 98% through column chromatography purification. Its structure is accurately characterized by means such as nuclear magnetic resonance (NMR) and mass spectrometry (MS).

[0192] Prepare the precursor solution: Weigh lead iodide (PbI 2 ), methylammonium iodide (CH 3 NH 3 I) according to the stoichiometric ratio, dissolve them in a mixed solvent of an appropriate amount of γ-butyrolactone (GBL) and dimethyl sulfoxide (DMSO) (volume ratio 3:1), add 2-PyBP to make its concentration reach 1% - 3% mol, and ultrasonically oscillate for 15 - 20 minutes to ensure complete dissolution.

[0193] Substrate treatment: The substrate material is successively ultrasonically cleaned with acetone, ethanol, and deionized water for 10 - 15 minutes. After drying with nitrogen, it is placed in a dopamine hydrochloride solution (concentration 2 - 3 mg / mL) and soaked for 6 - 8 hours at room temperature under alkaline conditions (pH 8 - 9) to enable in-situ polymerization of dopamine to form a polydopamine layer. After taking it out, it is rinsed thoroughly with deionized water and dried with nitrogen for standby.

[0194] Microwave synthesis: The treated substrate is placed into a microwave reaction device, and the precursor solution is dropped. The reaction is carried out according to the variable-power microwave radiation and microwave-vacuum cycle treatment process. After completion, it is annealed at 80 - 100 °C for 10 - 20 minutes under a nitrogen atmosphere to obtain a perovskite thin film.

[0195] Performance testing:

[0196] Through XRD analysis, the diffraction peak intensity of the perovskite thin film is high and the full width at half maximum is narrow, indicating that the crystallinity is increased by about 40% compared with the traditional process, proving that 2-PyBP and variable-power microwave synergistically promote crystal growth.

[0197] Atomic force microscope (AFM) detection shows that the surface roughness of the thin film is 6 - 8 nm, which is reduced by about 30% compared with the traditional method, benefiting from the improvement of the film density by the microwave-vacuum cycle.

[0198] Fabricating a perovskite solar cell, the photoelectric conversion efficiency reaches more than 22%, which is increased by about 18% compared with the traditional one, attributed to the optimization of the crystal structure by the nitrogen-containing heterocyclic borate ester and the improvement of the interface by polydopamine modification.

[0199] The material is subjected to a damp heat aging test (60 °C, 90% RH, 300 h), and the photoelectric performance attenuation is less than 8%, indicating that the enhanced structural stability of the material and the interfacial adhesion improve its environmental resistance.

[0200] Using X-ray photoelectron spectroscopy (XPS) to analyze the interfacial element distribution, it is found that a chemical bond is formed between polydopamine and perovskite, the element distribution is uniform, and the interface bonding is good, ensuring charge transport.

[0201] Example 12

[0202] Preparation by organophosphonate-modified microwave synthesis:

[0203] Material innovation:

[0204] A new type of organophosphonate compound is introduced, such as dimethyl vinylphosphonate (VPDM). It contains unsaturated vinyl and strongly polar phosphonate groups. In a microwave field, the vinyl can participate in free radical polymerization reactions to form a cross-linked network structure with the perovskite precursor, enhancing the mechanical strength of the material, especially suitable for the preparation of flexible devices. The phosphonate group can have a strong interaction with the metal halide precursor, regulating the hydrolysis and condensation rates of the precursor. Under rapid microwave heating, it can precisely control the crystal growth rate, reduce defect generation, and improve the optoelectronic performance.

[0205] Polyethylene glycol - polypropylene glycol - polyethylene glycol triblock copolymer (PEG - PPG - PEG, F127) is selected as the template agent. F127 can self - assemble into micelle structures in solution, encapsulating the precursor molecules. During microwave radiation, the micelles act as "microreactors", enabling the reaction to occur in a confined space, regulating the particle size and morphology of the perovskite material, forming a uniform nanostructure, increasing the specific surface area, and improving the light absorption and charge separation efficiency.

[0206] Method innovation:

[0207] A pulsed microwave - hydrothermal combined process is adopted. First, the precursor solution (containing VPDM and F127) is placed in a sealed reaction kettle for pulsed microwave radiation. Set the microwave power at 400 - 600 W, the pulse frequency at 1 - 2 Hz, and the radiation time at 5 - 10 minutes to rapidly heat the solution to 120 - 150 °C, initiating the preliminary reaction of the precursor and the polymerization of VPDM. Subsequently, a hydrothermal reaction is carried out at 120 - 150 °C for 1 - 2 hours. Utilizing the long - term constant temperature characteristic of the hydrothermal environment, it further promotes crystal growth and improves crystallinity. Combining with the rapid activation in the early stage of pulsed microwave, it synergistically enhances the material quality.

[0208] A gradient cooling strategy under a microwave field is developed. After the reaction ends, simultaneously with the cessation of microwave radiation, the gradient cooling program is initiated, cooling from the reaction temperature to 60 - 80 °C at a rate of 5 - 10 °C / min, then maintaining for 30 - 60 minutes, and then naturally cooling to room temperature. Gradient cooling can avoid stress defects in the crystal caused by rapid cooling, making the crystal structure slowly stable and optimizing the material performance.

[0209] Preparation process:

[0210] Synthesize VPDM: Esterification reaction of vinylphosphonic acid with methanol is carried out under the catalysis of concentrated sulfuric acid, and it is purified through steps such as distillation and rectification to obtain VPDM with a purity of over 97%. Its structure is confirmed by means such as NMR and FTIR.

[0211] Prepare the precursor solution: Lead iodide (PbI 2 ), methylammonium lead bromide (CH 3 NH 3 PbBr 3)Dissolve it in N-methylpyrrolidone (NMP) at a certain ratio, add VPDM (concentration 2%-4% mol) and F127 (concentration 0.5%-1% wt), and stir and ultrasonically mix evenly.

[0212] Microwave-hydrothermal reaction: Transfer the precursor solution to a high-pressure reaction kettle lined with polytetrafluoroethylene, and operate according to the pulsed microwave-hydrothermal combined process. After the reaction is completed, take out the sample, wash it with ethanol and deionized water, and dry it with nitrogen.

[0213] Gradient cooling: Place the sample in a microwave cooling device, execute the gradient cooling strategy, and obtain the perovskite material after completion.

[0214] Performance verification:

[0215] SEM observation shows that a uniform nanocubic perovskite structure is prepared, with a particle size of 200-300 nm, and the specific surface area is increased by 40%-60% compared with the traditional method, proving the effect of F127 template and process regulation.

[0216] Tensile test shows that the tensile strength of the perovskite film containing VPDM is increased by about 60%, meeting the mechanical requirements of flexible devices, which is attributed to the enhancement of the cross-linked network structure.

[0217] Fabricate a perovskite photodetector, and the response time is shortened to 20-30 μs, which is about 50% faster than the traditional one, thanks to the high crystallinity of the material and the optimized charge transport of the nanostructure.

[0218] Perform 10 repeated bending tests (bending radius 5-10 mm) on the material, and the photoelectric performance retention rate is above 90%, showing good flexible stability.

[0219] Thermogravimetric analysis (TGA) shows that the material decomposes slowly at high temperatures of 400-450 °C, and the thermal stability is improved. Gradient cooling helps to stabilize the crystal structure and reduce the tendency of thermal decomposition.

[0220] Example 13

[0221] Preparation by thiol-functionalized polymer-assisted microwave synthesis:

[0222] Material innovation:

[0223] Design and synthesize a thiol-functionalized polythiophene derivative (PT-SH), whose main chain is a polythiophene structure with good conductivity, and a thiol group is introduced into the side chain. Under microwave radiation, the thiol group can have a strong coordination effect with metal ions in the perovskite precursor, guide the directional assembly of the precursor, promote crystal nucleation and growth, and improve crystallinity. At the same time, the conjugated structure of the polythiophene main chain is beneficial to charge transport, improves the electrical properties of the material, and forms a synergistic photoelectric effect with the perovskite.

[0224] Chitin nanofibers (CNF) are used as a composite additive. CNF has excellent mechanical properties, biocompatibility, and a high specific surface area. It is mixed into the precursor solution at 1%-3% wt. Under microwave action, CNF interweaves with perovskite. On the one hand, it enhances the overall mechanical strength of the material and improves the film flexibility; on the other hand, functional groups such as hydroxyl groups on its surface can adsorb the precursor, regulate the local reaction concentration, promote uniform reaction, and optimize the microstructure of the material.

[0225] Method innovation:

[0226] The multi-mode microwave radiation and mechanical stirring linkage process is applied. During microwave radiation (power 500 - 700W), mechanical stirring is carried out at a speed of 200 - 300 rpm simultaneously. The multi-mode microwave makes the reaction system heat more uniformly, and mechanical stirring overcomes the reactant concentration gradient. The two work together to accelerate the reaction process, shorten the preparation time by 30% - 40%, and improve the material uniformity.

[0227] The solvent vapor annealing step of microwave post-treatment is introduced. After microwave synthesis of perovskite materials, the sample is placed in a sealed container containing a small amount of solvent (such as isopropanol) vapor and annealed for 5 - 10 minutes under microwave radiation (power 200 - 300W). The solvent vapor can penetrate into the material interior. With the assistance of the microwave thermal effect, crystal defects are repaired, grain boundary properties are optimized, and the optoelectronic properties are further improved.

[0228] Preparation process:

[0229] Synthesize PT-SH: Through the copolymerization reaction of thiophene monomers and monomers containing mercapto functional groups, PT-SH with a moderate molecular weight and a purity higher than 96% is obtained through purification. NMR, GPC, etc. are used to characterize the structure and molecular weight.

[0230] Prepare the precursor solution: Dissolve lead iodide (PbI 2 ), methylammonium lead iodide (CH 3 NH 3 PbI 3 ) in a mixed solvent of DMF and DMSO (volume ratio 2:1), add PT-SH (concentration 0.5% - 1.5% wt) and CNF, and mix evenly by ultrasonic and stirring.

[0231] Microwave synthesis: Place the precursor solution in a multi-mode microwave reaction device, equipped with mechanical stirring, and react according to the set process parameters. After completion, take out the sample and let it cool naturally.

[0232] Solvent vapor annealing: Put the cooled sample into a container containing isopropanol vapor and carry out the solvent vapor annealing of microwave post-treatment. After completion, the perovskite film is obtained.

[0233] Performance testing:

[0234] XRD analysis shows that the crystal diffraction peaks are sharp, and the crystallinity is increased by about 35% compared with the traditional method, proving that the PT-SH coordination and microwave-stirring synergistically promote crystallization.

[0235] The four-point probe method is used to measure the film resistance, and the resistance value is reduced by about 40%. Thanks to the improvement of charge transport by the polythiophene backbone, it shows that the electrical properties are optimized.

[0236] A flexible perovskite solar cell is fabricated. After 500 bends, the photoelectric conversion efficiency remains above 85%. The CNF and PT-SH synergistically ensure flexibility and stability.

[0237] The micro-photoluminescence spectrum shows that the luminescence intensity of the material is increased by about 30% after solvent vapor annealing, indicating that the grain boundaries are optimized, non-radiative recombination is reduced, and the optoelectronic properties are improved.

[0238] The material is tested for cytotoxicity, and the cell survival rate is above 90%, showing good biocompatibility and meeting the potential for biomedical applications.

[0239] Example 14

[0240] Preparation by cyclodextrin inclusion complex assisted microwave synthesis:

[0241] Material innovation:

[0242] Prepare a cyclodextrin-perovskite precursor inclusion complex. β-cyclodextrin (β-CD) is selected, which has a unique cyclic structure. Its internal hydrophobic cavity can include perovskite precursor molecules (such as lead iodide) to form a host-guest inclusion complex. During microwave radiation, the inclusion complex can control the release rate of the precursor, make the reaction proceed smoothly, avoid agglomeration or non-uniform reaction caused by too high instantaneous concentration of the precursor, and is beneficial to the formation of high-quality crystals. At the same time, the hydroxyl groups outside β-CD can interact with solvent molecules, improve the fluidity of the solution, promote the diffusion of reactants, and enhance the reaction efficiency.

[0243] Sodium polystyrene sulfonate (PSS) is introduced as a surfactant. PSS has negatively charged sulfonic acid groups, which can be adsorbed on the surface of precursor particles in solution and prevent particle agglomeration through electrostatic repulsion, ensuring uniform dispersion of the precursor. Under microwave action, PSS and β-CD act synergistically to further optimize the stability of the reaction system and improve the uniformity and optoelectronic properties of the perovskite material.

[0244] Method innovation:

[0245] Adopt a pre-inclusion - microwave radiation step-by-step process. First, mix lead iodide with β-CD in an aqueous solution and stir at room temperature for 1 - 2 hours to form an inclusion complex. Then, add other precursors (such as methylammonium iodide) and PSS, and after ultrasonic dispersion, perform microwave radiation. Set the microwave power to 400 - 600 W and the radiation time to 3 - 5 minutes. Utilize the rapid heating of microwave to release and react the precursors in the inclusion complex, precisely control the reaction process, and reduce the generation of defects.

[0246] Combine with an ultrasonic-assisted crystallization step after microwave radiation. Immediately after the microwave radiation ends, perform ultrasonic treatment on the reaction system with a frequency of 30 - 50 kHz and a time of 10 - 20 minutes. The ultrasonic vibration promotes the further growth and perfection of the crystals, and at the same time breaks the possible small aggregates formed, improving the uniformity and crystallinity of the material, and synergistically optimizing the material properties with microwave radiation.

[0247] Preparation process:

[0248] Prepare β-CD - lead iodide inclusion complex: Dissolve β-CD and lead iodide in deionized water according to a molar ratio of 2:1 - 3:1, stir to form an inclusion complex solution, and characterize the inclusion situation by means of XRD, NMR, etc.

[0249] Prepare the precursor solution: Add methylammonium iodide and PSS (concentration 0.3% - 0.6% wt) to the inclusion complex solution, and ultrasonically vibrate for 10 - 15 minutes to ensure uniform mixing.

[0250] Microwave synthesis: Transfer the precursor solution to a microwave reaction device, and carry out the reaction according to the pre-inclusion - microwave radiation step-by-step process. After completion, take out the sample.

[0251] Ultrasonic-assisted crystallization: Place the sample in an ultrasonic device, perform the ultrasonic-assisted crystallization step, and obtain a perovskite thin film after completion.

[0252] Performance verification:

[0253] SEM observation shows that the perovskite thin film has uniform grains, an average particle size of about 400 nm, and no obvious aggregation, proving that the inclusion of β-CD and PSS synergistically ensures uniformity.

[0254] Transmittance spectrum analysis shows that the transmittance of the material in the visible light band increases by about 20%, which is beneficial to the light absorption and transmission of optoelectronic devices, due to the uniform crystal structure.

[0255] Fabricate a perovskite light-emitting diode (LED) with a luminous efficiency of 1300 cd / m 2 The above is about 45% higher than the traditional one, attributed to the reduction of internal defects in high-quality crystals and the improvement of luminous performance.

[0256] The material was prepared and tested 5 times repeatedly, and the deviation of optoelectronic performance was less than 4%, showing process stability and ensuring material consistency.

[0257] The thermal properties of the material were tested by thermal analysis (DSC). The thermal decomposition temperature increased by about 10 °C, indicating that β-CD and ultrasonic assistance stabilized the crystal structure and enhanced the thermal stability.

Claims

1. A green preparation process for perovskite semiconductor materials by microwave-assisted synthesis, characterized in that: include: A novel organic-inorganic hybrid perovskite precursor is used, wherein the precursor comprises a biocompatible organic cation replacing a traditional toxic organic amine and coordinated with an inorganic metal halide to form a perovskite structure; Introducing a green solvent system, using environmentally friendly mixed solvents to dissolve precursors; Use microwave radiation to accelerate the reaction process. By precisely controlling the microwave radiation parameters, including power between 100-1000W and radiation time between 1-10 minutes, the reaction system can quickly reach the expected reaction temperature to achieve rapid crystal growth of the material. Optionally, an intermittent microwave radiation process is used to divide the synthesis process into multiple radiation cycles, each cycle has a radiation time of 30-60 seconds and an intermittent time of 10-30 seconds, and the intermittent period is used to promote uniform growth of crystals; The microwave and ultrasound can be selectively combined for synergistic synthesis, and ultrasonic vibration with a frequency of 20-100kHz is introduced simultaneously with microwave radiation, and the ultrasonic cavitation effect is used to accelerate the reaction process and improve the crystallinity of the material; Optionally, the in-situ growth and microwave curing can be integrated to directly grow the perovskite film in-situ on the substrate material and simultaneously cure it by utilizing the microwave penetration; Optionally, microwave-based post-processing optimization can be used to perform microwave annealing on the prepared perovskite material, with the temperature controlled at 150-250° C. for 1-5 minutes to eliminate residual stress inside the material and repair crystal defects; Alternatively, a microwave-assisted template method can be used to guide the growth of perovskite materials using micro-nano templates to form perovskite materials with specific morphology and size; Microwave-induced self-assembly can be used to prepare the product. By adjusting microwave frequency, electric field intensity and other parameters, the precursor molecules are induced to self-assemble to form perovskite nanoclusters or supramolecular structures with an ordered structure. Optionally implement step-by-step microwave synthesis of multiple precursors. For complex multi-perovskite systems, microwave radiation treatment is performed on different precursors in sequence to ensure accurate synthesis of perovskite materials with ideal chemical composition and structure. A microwave-assisted green recycling and reuse process can be optionally used to perform microwave-assisted decomposition and recovery of waste materials in the process of preparing perovskite materials, recycle raw materials and treat waste materials containing heavy metals.

2. The preparation process according to claim 1, characterized in that: In the microwave-induced surfactant-assisted synthesis preparation: Using new bio-based surfactants, such as sophorolipids, which self-assemble in solution to form micellar structures, added to the precursor solution at a concentration of 0.5%-1%wt to reduce precursor agglomeration and guide the directional arrangement of precursor molecules; Introducing fullerene derivatives as electron transport layer additives, such as C 60 -Methyl butyrate (C 60 -PCBM), mixed into the precursor solution at a ratio of 5%-10%wt to enhance the electron transport capacity; Using degradable polylactic acid-glycolic acid copolymer (PLGA) as the substrate modification material, a PLGA layer with a thickness of about 50-100nm is spin-coated on the substrate to enhance adhesion and be naturally degradable; Use pulse modulated microwave radiation with a power between 300-600W and a 50% duty cycle, i.e. 0.5-1s of radiation followed by a 0.5-1s pause to avoid local overheating and material decomposition; Combined with vacuum-assisted technology, the reaction vessel is placed in a low vacuum environment of 10-100 mbar during the microwave radiation synthesis process, which promotes rapid evaporation of the solvent and improves the density of the film.

3. The preparation process according to claim 1, characterized in that: In the dual-frequency microwave collaborative synthesis preparation: Design a dual metal organic framework (MOFs) doped precursor, mix zirconium-based MOF (UiO-66) and titanium-based MOF (MIL-125) in a ratio of 1:1-3:1 and blend with the perovskite precursor, and use the high specific surface area and regular pore structure of MOFs to regulate the perovskite microstructure; The ionic liquid 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) is mixed with ethanol in a volume ratio of 1:2-1:3 to enhance microwave absorption and conduction and reduce pollution; Using dual-frequency microwave radiation, the main frequency is set at 2.45GHz, the auxiliary frequency is 5.8GHz, and the power is controlled at 400-700W and 100-300W respectively, to synergistically enhance the molecular vibration and reaction activity of the precursor; Develop a dynamic temperature feedback control algorithm to monitor the reaction temperature in real time based on infrared temperature measurement. When the temperature deviation exceeds ±5°C, the dual-frequency microwave power is intelligently adjusted to ensure accurate and stable reaction temperature. Introduce rotating magnetic field stirring, apply 50-100G rotating magnetic field simultaneously with microwave radiation, so that the solution in the reaction container is driven to rotate by Lorentz force, strengthen the mixing of reactants and improve the uniformity of materials.

4. The preparation process according to claim 1, characterized in that: In the microwave-assisted supercritical fluid synthesis preparation: Supercritical carbon dioxide (scCO2) is used as a reaction medium and template. When the precursor solution is prepared, scCO2 is injected into a high-pressure reactor containing the precursor to induce the precursor to self-assemble into a nanostructure. Introducing sulfur-containing organic ligands, such as dithiobenzothiazole (MBT), to modify the precursor, coordinate with the metal halide precursor at a 2%-5% mol ratio to adjust the perovskite energy level structure and stabilize crystal growth; Design a microwave-supercritical fluid coupling reaction system, first mix the precursor and scCO2 under high pressure, heat it to 80-120℃ and then turn on microwave radiation with a power of 500-800W, and use the superposition of microwave and supercritical fluid thermal and non-thermal effects to accelerate the reaction; Adopting a gradient pressure reduction strategy, after the reaction is completed, the pressure is slowly reduced at a rate of 0.1-0.5MPa / min to allow scCO2 to be released smoothly, ensuring the integrity of the nanostructure and improving the stability of the material; An online in-situ monitoring system is established, combining Raman spectroscopy with high-voltage visual window technology to observe the reaction process and material structure changes in real time, and optimize the reaction parameters immediately based on feedback.

5. The preparation process according to claim 1, characterized in that: In the microwave-assisted aerosol jet synthesis preparation: Prepare aerosol precursors, and make aerosol solutions of perovskite precursors and polymer binder polyvinyl pyrrolidone (PVP). PVP improves the dispersion of the precursors, prevents agglomeration, and enhances the mechanical strength of the materials. Doping quantum dots, such as cadmium sulfide quantum dots (CdSQDs), is mixed into the precursor aerosol solution at 1%-3%wt to broaden the light absorption range of the perovskite material and promote the generation of photogenerated carriers; A microwave-assisted aerosol jet deposition system was constructed. After the precursor aerosol was ultrasonically atomized, it was carried by a carrier gas through a microwave radiation zone. The microwave power was set to 600-900W. The aerosol precursor was instantly solidified and deposited on the substrate by rapid microwave heating, achieving one-step rapid film formation. A multi-layer spray deposition strategy is used to alternately spray precursor aerosols of different compositions to construct multi-layer perovskite films and precisely control the material composition and energy band structure. Combined with in-situ plasma treatment, after aerosol deposition, low-power (50-100W) plasma treatment is introduced for 10-30s to clean the surface, repair defects, and enhance the adhesion between the film and the substrate.

6. The preparation process according to claim 1, characterized in that: In the microwave-assisted bio-template synthesis preparation: Using filamentous fungi, such as Trichoderma, as biological templates, pre-treating them after cultivation to remove impurities and retain the filamentous network structure, infiltrating the biological template with a perovskite precursor solution to form a bionic structure, thereby improving the mechanical properties and specific surface area of ​​the material; Introducing natural pigments such as chlorophyll or anthocyanin, adding 0.5%-2%wt to the precursor solution, broadens the light absorption range of the perovskite material; Design a microwave-biotemplate in-situ reaction system, place the biotemplate soaked with the precursor in a microwave field, set the power to 400-700W, and use the microwave thermal effect to cause the precursor to react and crystallize quickly in the biotemplate, solidify to form a perovskite material, while retaining the structural characteristics of the biotemplate; The step-by-step drying-carbonization process is used to first gently dry at 60-80°C to remove most of the solvent, and then carbonize the bio-template at 400-600°C under nitrogen protection to convert it into a carbon skeleton-supported perovskite material, enhancing conductivity and stability. Build an optoelectronic collaborative testing platform to monitor in real time the changes in the optoelectronic properties of materials under light and electric fields, and use feedback to optimize microwave reaction parameters and bio-template processing conditions.

7. The preparation process according to claim 1, characterized in that: In the nitrogen-containing heterocyclic borate ester assisted microwave synthesis preparation: 2-Pyridylboronic acid pinacol ester (2-PyBP) is used as a nitrogen-containing heterocyclic borate compound, which forms a stable coordination bond with the metal ions in the perovskite precursor to guide the precursor molecules to be arranged in an orderly manner. The concentration of 2-PyBP added to the precursor solution is 1%-3% mol; Using a polydopamine-modified substrate material, dopamine is in situ polymerized on the substrate surface to form a polydopamine layer with a thickness of about 30-50 nm, thereby enhancing the adhesion between the substrate and the perovskite film and synergistically regulating the growth of the perovskite material; Using variable power microwave radiation technology, the power is 300-400W in the initial stage of the reaction, which lasts for 1-2 minutes, and then gradually increases to 600-800W in the later stage, which lasts for 2-3 minutes, and accurately supplies energy according to the progress of the reaction; Combined with microwave-vacuum cycle treatment, during the microwave irradiation process, the environment is periodically switched to a vacuum environment every 30-60 seconds, with a vacuum degree of 50-100 mbar. The environment is maintained for 10-20 seconds before microwave irradiation is resumed, which promotes rapid evaporation of the solvent and improves the purity of the material.

8. The preparation process according to claim 1, characterized in that: In the organic phosphonate modified microwave synthesis preparation: Vinylphosphonic acid dimethyl ester (VPDM) is introduced as an organic phosphonate compound, which contains unsaturated vinyl groups and strongly polar phosphonate groups, and forms a cross-linked network structure with the perovskite precursor. The concentration of VPDM added to the precursor solution is 2%-4% mol, which enhances the mechanical strength of the material. Polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer (PEG-PPG-PEG, F127) was selected as a template agent to self-assemble in the solution to form a micellar structure, and the particle size and morphology of the perovskite material were regulated to form a uniform nanostructure. The concentration of the precursor solution added was 0.5%-1%wt; The pulse microwave-hydrothermal combined process is adopted. First, pulse microwave radiation is carried out with a power of 400-600W, a pulse frequency of 1-2Hz, and a radiation time of 5-10 minutes to quickly heat the solution to 120-150°C, initiating the initial reaction of the precursor and the polymerization of VPDM. Then, a hydrothermal reaction is carried out at 120-150°C for 1-2 hours to synergistically improve the quality of the material. A gradient cooling strategy was developed under the microwave field. After the reaction, the reaction temperature was reduced from 60-80°C at a rate of 5-10°C / min, then maintained for 30-60 minutes, and then naturally cooled to room temperature to avoid stress defects in the crystal due to sudden cooling.

9. The preparation process according to claim 1, characterized in that: In the thiol functionalized polymer assisted microwave synthesis preparation: The thiol-functionalized polythiophene derivative (PT-SH) was designed and synthesized. Its main chain is a polythiophene structure, and a thiol group is introduced into the side chain. It has a strong coordination effect with the metal ions in the perovskite precursor, guides the precursor to directional assembly, and is added to the precursor solution at a concentration of 0.5%-1.5%wt to improve crystallinity. Chitosan nanofibers (CNF) are used as composite additives, mixed into the precursor solution at 1%-3%wt, interweaving with perovskite to enhance the overall mechanical strength of the material, improve the flexibility of the film, and regulate the local reaction concentration; The multi-mode microwave radiation and mechanical stirring linkage process is used. During the microwave radiation process, the power is 500-700W, and the mechanical stirring is performed at a speed of 200-300rpm, which synergistically accelerates the reaction process, shortens the preparation time by 30%-40%, and improves the uniformity of the material. A solvent vapor annealing step is introduced into microwave post-treatment. After microwave synthesis of perovskite material, the sample is placed in a sealed container containing a small amount of solvent, such as isopropanol vapor, and annealed for 5-10 minutes under microwave radiation at a power of 200-300W to repair crystal defects and optimize grain boundary properties.

10. The preparation process according to claim 1, characterized in that: In the preparation of cyclodextrin inclusion complexes assisted by microwave synthesis: Prepare a cyclodextrin-perovskite precursor inclusion complex, select β-cyclodextrin (β-CD), the internal hydrophobic cavity of which includes a perovskite precursor molecule, such as lead iodide, to form a host-guest type inclusion complex, and dissolve β-CD and lead iodide in deionized water at a molar ratio of 2:1-3:1, and stir to form an inclusion complex solution; Sodium polystyrene sulfonate (PSS) is introduced as a surfactant and added to the precursor solution at a concentration of 0.3%-0.6%wt. It is adsorbed on the surface of the precursor particles and prevents the particles from agglomerating through electrostatic repulsion, ensuring uniform dispersion of the precursor. The pre-inclusion-microwave irradiation step-by-step process is adopted. First, lead iodide and β-CD are mixed in an aqueous solution and stirred at room temperature for 1-2 hours to form an inclusion complex. Then other precursors and PSS are added, and microwave irradiation is performed after ultrasonic dispersion. The power is set to 400-600W and the irradiation time is 3-5 minutes to accurately control the reaction process. Combined with the ultrasonic assisted crystallization step after microwave radiation, the reaction system is immediately subjected to ultrasonic treatment at a frequency of 30-50kHz for 10-20 minutes after the microwave radiation is completed, so as to promote further growth and improvement of the crystals and improve the uniformity and crystallinity of the material.