Study On Preparation And Performance Of Lead-free Perovskite Materials

Perovskite solar cells have attracted much attention in recent years,and the conversion efficiency has exceeded 23%.However,the toxicity of lead has seriously affected the commercialization of lead,so the research on lead-free alternatives has attracted much attention.Ge and Sn have been studied,but Sn2+and Ge2+are unstable and easily to be oxidized,so they are not suitable for perovskite solar cells.In this paper,we found a mixed double perovskite GA2CuBiI6(GA is guanidine ion)and calculated it by the first principle.The calculation shows that it has suitable band gap and good optical absorption,and can be used in perovskite solar cells.Then GA2CuxK1-xBiI6 double perovskite materials were synthesized by solution method.We studied the structure,morphology,stability and photoelectric properties of guanidine salt double perovskite membrane by XRD,SEM,UV-vis,PL and other methods.The results show that it is not only non-toxic and stable,but also has good photoelectric properties.Although we only get a very small conversion efficiency,it provides a feasible alternative for the study of lead-free perovskite cells.Because the copper is non-toxic and cheap,so in this paper,we also studied the Cu perovskite samples and optimized them by doping different proportion of iodoaniline and guanidine salt different concentration and PEG doping.When the ratio of iodoaniline to guanidine salt is 3:2 and the concentration of precursor is 1.5 mol/L,the perovskite thin film is the best and has a suitable band gap about 1.6 eV.Although the grain size of PEG doped perovskite film is larger,the morphology of the film is not good,so further study is needed.