Optimization Of The Active Layer Of Tin-based Perovskite Solar Cells

As the third generation of new solar cells,perovskite solar cells have achieved the highest efficiency of 25.2%.However,due to the great harm of lead to the environment and human body,tin with its low toxicity has become an ideal substitute.At present,the performance of tin-based perovskite solar cells is far less than that of lead-based solar cells.The purpose of this paper is to improve the performance of tin-based cell.There are altogether 34 figures,6 tables and 66 references,which are mainly divided into the following two parts:?1?Diethylamide iodide?DAI?was added to the precursor solution to improve the morphology of formamidinium tin iodide?FASn I₃?films.The morphology characterization shows that the addition of DAI significantly promotes the quality of FASn I₃ films.The effect of film improvement is verified through device characterization.The photoelectric conversion efficiency of the device with addition of DAI increases from 3.98%to 4.80%,achieving an increase of about 20%.?2?In order to reduce the defects tracing to tetravalent tin(Sn⁴⁺),hydrazine monohydrobromide?N₂H₅Br?was used to doped FASn I₃ perovskite as strong reducing hydrazine.The fitting data of X-ray photoelectron spectroscopy quantitatively verified that N₂H₅Br effectively inhibited the formation of Sn⁴⁺.The results of ideal factor test and transient open circuit voltage delay test qualitatively prove that N₂H₅Br doping reduces internal defects of FASn I₃.At the same time,N₂H₅Br doping can increase the bandgap of tin-based materials.Attributing to N₂H₅Br addition,the efficiency of FASn I₃-based perovskite solar cell achieved 7.81%.