Optimal Design Of Bulk Phase And Interface In Perovskite Solar Cells

As we gradually realized that resources such as coal,oil,and natural gas could no longer meet the energy needs of human beings in the future,more and more countries and regions in the world are turning their attention to the use of solar energy resources.With decades of development,the photovoltaic industry has settled on the top spot in the field of solar energy utilization.Since it was invented in 1954,the conversion efficiency of silicon solar cell has increased from 6%at the beginning to more than 26%,and is getting closer to its 29%limit efficiency.Although scientists from various countries are still working hard to further improve the efficiency of silicon batteries,under the constraints of physical laws,every point of improvement in the process of approaching the 29%limit efficiency will require munch more efforts.Many new solar cells were invented after the silicon cell,mainly the second-generation thin-film solar cells.Due to various problems,the second-generation solar cells did not shake the throne of crystalline silicon cells.However,the new subversive has emerged and ready to replace silicon solar cells,this is the perovskite solar cell.In 2009,the efficiency of the perovskite solar cell was only 3.8%when it was first invented,after 11 years development,the highest efficiency of a single-cell perovskite battery has exceeded 25%.Previous studies have shown that the theoretical upper limit of perovskite batteries is as high as 33%.In order to approach the limit of efficiency,the academic community has made many efforts.There are still many problems to be solved,such as lack of efficiency,poor stability,and toxicity of lead ions.An important way to solve these problems is to continuously improve and optimize the problems of the bulk phase and interface in perovskite solar cells.A lot of work has been done by researchers on both bulk phase and interface optimization.Such as bulk doping,post-treatment,solvent engineering,interface modification and so on.This article aims to improve the performance and stability of the cell by modify the bulk phase and interface in perovskite solar cells.The specific researches are as follows:(1)Improve the quality of perovskite thin films by ameliorate the two-step sequential deposition method.The main efforts are to solve the problems of poor morphology and low crystallinity of the perovskite films prepared by this method.The iodine element is added to the lead iodide precursor required in the two-step process to create pores,which affects the process of reaction to form perovskite and affects the quality of final perovskite film.As a result,a higher quality perovskite film is obtained.(2)The aim is to synergic optimization of electron transport layer(ETL)and the ETL/perovskite interface by modifying the ETL.Based on the flat-structured perovskite battery using SnO2 layer as the ETL,the improving of the properties of the ETL and the interface was achieved by adding NH4Cl to the SnO2 precursor,and the device performance was improved.(3)In addition to the bulk phase and the interface between layers,attempts have been made to effectively passivate defects at the grain boundaries of the perovskite film.Through literature research and multiple attempts,it was found that the perovskite grain boundaries can be effectively passivated by post-treatment method using 2-aminoterephthalic acid,the overall performance of the device was improved.