Studying the Effect of Chlorine Introduction in Perovskites through Various Routes and Fabrication of Perovskite Solar Cells

Abstract

In the recent years, the perovskite solar cells (PSCs) have evolved exponentially in terms of its efficiency since 2009 and since then there has been an enormous research in this field to pull up the efficiency. These accomplishments in the performance are by virtue of its superior optoelectronic properties that includes micrometre range diffusion lengths due to high crystallinity, strong light absorption potential with feasibility of band gap tuning, and ambipolar charge transfer capabilities. This project focused on two areas firstly on device fabrication along with its optimization and secondly to studying the effect of chlorine introduction in perovskite through various routes. In the first half of the thesis, fabrication of the perovskite solar cells (MAPbI3 and FACsPb(I0.83Br0.17)3 based) were done along with the optimization in terms of temperature, RPM, spin coating time, annealing time and temperature followed by some characterisations. The other half was to studying the effect of chlorine introduction in perovskite through various routes. Different salts with significant stoichiometry were used to maintain the perovskite structure (ABX3). The chloride introduction was taken through organic salts as well as inorganic ones namely methyl ammonium chloride (MACl), formamidine hydrochloride (FACl), lead chloride (PbCl2) and hydrochloric acid (HCl). It was observed that the precursor which used Chloride through lead has a better optical properties in terms of defect states and charge transportation. Further the device fabrication were done by using these different perovskite precursor solution. Finally, it was found that the device in which chlorine is introduced from lead in the perovskite precursor has the highest efficiency among all.