Study On The Photoelectric Properties And Stability Of Perovskite Solar Cells Prepared By Wet Method

In recent years,perovskite solar cells have become a research hotspot at home and abroad because of their high photoelectric conversion efficiency and low cost solution method.However,the application of perovskite solar cell is restricted by the instability of devices due to the tendency of perovskite material to decompose in the air and the overall cost of using the noble metal electrode in the structure of the perovskite solar cells.In this paper,in order to reduce the preparation cost,optimize the structure and improve the stability of the perovskite solar cell,a carbon electrode prepared by low temperature carbon paste was used in the hole-transport layer free of perovskite solar cells.Firstly,the compact layer and the perovskite layer were prepared by different processes and their effects on the photoelectric properties of the solar cells were investigated.The compact layer was prepared by one spin-coating and twice spin-coating,respectively.The results showed that FTO substrate can completely covered by the compact layer with twice spin-coating,and the thickness has reached around 70 nm.And the prepared solar cells had better performance and obtained 4.94%photoelectric conversion efficiency.The perovskite layers were prepared by the traditional two-step method and the new two-step method,respectively.In the traditional two-step method,when the spin-coating speed was 4000rpm,the morphology of perovskite was the best and the solar cell efficiency received 4.99%.In the new two-step method,after three times of spin-coating of methyl ammonium iodide,a PbI2-free,smooth and dense perovskite film was prepared,and the performance of the perovskite solar cells had been improved,finally obtained a photoelectric conversion efficiency of 6,08%.Secondly,the stability of the perovskite solar cells in the air and the ultraviolet light stability in the air were studied.The unpackaged perovskite solar cells were placed in the air to study the stability.The results show that the perovskite solar cells after being placed in the air for more than 21 days,the efficiency can still be maintained at an initial efficiency of 89.5%or more.Using Al2O3 instead of TiO2 as a mesoporous layer,after 48h of UV light irradiation,the efficiency of the perovskite solar cells can still maintain the original efficiency of more than 90%.Therefore,the replacement of TiO2 with Al2O3 as the scaffold layer of perovskite layer helps to improve the UV light irradiation stability of perovskite solar cells in the air.