Preparation And Performance Optimization Of Perovskite Solar Cells Based On Low-toxic Anti-solvent Treatment

In recent years,perovskite materials have shown easy-to-adjust light absorption capacity,excellent crystallinity,bipolar charge transport properties,long carrier diffusion distance and life,solution processability,and low cost.It has huge potential in the field of photovoltaics and energy,which has attracted widespread attention from the academic community,and is considered to be the important green energy material.The photoelectric conversion efficiency of solar cell devices based on organic-inorganic hybrid perovskite materials has rapidly increased from the initial 3.8%to 25.5%,demonstrating extremely high commercial value and application prospects.However,organic-inorganic hybrid perovskite cells also face problems such as complex preparation processes and high toxicity,which also limit the application of such materials.This thesis focuses on the low-toxicity preparation process of positive or trans-perovskite cells by adjusting the components of the light-absorbing layer of perovskite solar cells and Antisolvent treatment.The main tasks are as follows:1.We use the less toxic anhydrous lead acetate as the lead source and ethyl acetate as the anti-solvent to prepare organic-inorganic hybrid perovskite cells.Then dissolve it in N,N-dimethylformamide（DMF）at the ratio of the amount of methylammonium iodide and lead acetate at a ratio of 3:1,use ethyl acetate as the green anti-solvent,and add it by adjusting the anti-solvent The MAPbI₃perovskite solar cell with higher film quality was prepared by the one-step spin-coating method for the time and rotation speed of the spin coating.Experimental results show that ethyl acetate as an anti-solvent can effectively increase the grain size,crystallinity and carrier lifetime of the perovskite film,and reduce the internal defect state density of the perovskite film.In addition,the solar cell prepared with this light-absorbing layer has an open circuit voltage of 1.05 V,a short-circuit current density of20.5 mA cm^-2,a fill factor of 76.8%,and a photoelectric conversion efficiency of 16.6%.2.Through component engineering,the organic-inorganic hybrid perovskite cell is prepared by using the low-toxic lead acetate and lead iodide mixed solution as the precursor.By changing the ratio of lead acetate to lead iodide in the precursor solution,a series of perovskite films with different crystal exposed surfaces were synthesized to study the effect of lead source ratio on the properties of MAPbI₃films.Experiments show that when the amount ratio of lead acetate and lead iodide is 94:6,the synthesized thin-film perovskite cell has the best performance,with a photoelectric conversion efficiency of 15.3%,an open circuit voltage of 1.05 V,a short-circuit current density of 19.7 mA/cm²,and which the fill factor is 74.1%.The introduction of a small amount of PbI₂improves the grain size,crystallinity and carrier lifetime of the perovskite film.When the introduced PbI₂is excessive,the crystal structure will be deformed,the exposed surface of the crystal will change,and the crystallinity and optical properties of the film will decrease.3.We prepared a CsPbBr₃all-inorganic perovskite cell by adjusting the material of the hole transport layer and using a two-step method with low-toxic isopropanol as an anti-solvent.The anti-solvent treatment of isopropanol makes the PbBr₂film no longer need to be annealed,which simplifies the preparation steps and effectively improves the quality of the CsPbBr₃perovskite film.This greatly reduces the tiny holes and defects on the film,and increases the size of the crystal grains.The solar cell prepared by using this as a light-absorbing layer has a photoelectric efficiency of 4.53%.And then introduced between perovskite layer and carbon electrode has many levels gradient hole transport layer material,the multi-stage level of implementation charge transfer,reduce the level of charge transfer process step,so as to improve the transmission performance of cell charge,improve the photoelectric conversion efficiency of batteries,reduce the energy level difference,effectively promoted the photoproduction charge separation.The prepared all-inorganic perovskite solar cell device has a photoelectric conversion rate of 6.49%,an open circuit voltage of 1.234 V,a short circuit current density of 7.07 mA·cm^-2,and a filling rate of 74%.