Study On SnO₂ Electron Transport Layer, Additives And Interface Modification Of Perovskite Solar Cells

The electron transport layer of perovskite solar cell should have good energy level matching,large electron mobility,high transmittance,good stability,easily processing,and low cost.However,the traditional TiO₂ electron transport layer has low electron mobility and high catalytic activity,which is not conducive to the stability of perovskite solar cell.Thus,it is necessary to explore new electron transport layer materials and preparation methods.The thermal stability of MAPbI₃ solar cells are poor.It can be improved by using formamidine(FA_0.85MA_0.15PbI₃)and all inorganic CsPbI₃ perovskite materials,formamidine(FA_0.85MA_0.15PbI₃)perovskite material can also broaden the absorption range of the solar cells.In this dissertation,SnO₂ electron transport layer with high quality were prepared by magnetron sputtering and high-temperature oxidation.Besides,high-quality perovskite films of FA_0.85MA_0.15PbI₃ and CsPbI₃ were prepared by spin coating.Interface modification of FA_0.85MA_0.15PbI₃ cell by SbCl₃ and adding CsPbI₃ with Sb³⁺ were studied respectively.The study results are as follows:1.For the first time,SnO₂ electron transport layer was prepared by magnetron sputtering and high temperature oxidation.The quality of SnO₂ film was improved by adjusting the thickness and oxidation temperature of SnO₂ film.UV-Vis,PL/TRPL and EIS characterization showed that,the oxidation degree and the light transmittance of the film increased with the increase of oxidation temperature;with the decrease of SnO₂ film thickness,the light transmittance increases,the photoluminescence intensity and the carrier lifetime of MAPbI₃ film decreases first and then increases,and the transfer resistance decreases.The results show that the light transmittance,charge extraction and transfer performance of the SnO₂ electron transport layer are improved.When the thickness is 10 nm and the oxidation temperature is 460?,the SnO₂ electronic transport layer and corresponding solar cell have the best performance.The PCE of the cell is 16.39%,and the PCE drops less than 10%after the cell is placed in 30%humidity in air for 1000 hours.2.The effects of SbCl₃ interface modification layer on the performance of FA_0.85MA_0.15PbI₃ perovskite solar cell were studied.The best preparation conditions were obtained by adjusting the concentration of SbCl₃ solution and spin coating speed.The test of electron mobility shown that the SbCl₃ modification of TiO₂ improved the electron mobility of TiO₂ electron transport layer,which was helpful to improve the electron separation and extraction efficiency,reduce the recombination of carriers,and improve the Jsc and FF of the device.The best solar cell efficiency of 19.61%was gained when the solution concentration and spin coating speed are 5mg/ml and 4000rpm,respectively,and the device performance decay in ambient air with 30%relative humidity is less than 5%for 7 days.3.The effect of Sb³⁺ additive on the performance of CsPbI₃ perovskite solar cell was studied.CsPbI₃ perovskite solar cells with PCE of 15.12%were prepared by spin coating.The structure and stability of CsPbI₃ perovskite films were improved by adjusting the concentration of Sb³⁺ additive in precursor solution.The measurement results from XRD,UV-Vis,SEM and EDX showed that Sb³⁺ can enter the interstitial position of CsPbI₃ lattice and improve the stability of CsPbI₃.