Organo metal halide perovskites synthesis characterization and use in solar cells

Abstract

This thesis has concentrated on a young generation of solar cells called perovskite solar cell (PSC). It was introduced as a sensitizer in a dye-sensitized solid-state solar cell by Kojima et al. in 2009. It was used as an active layer and become known as PSC in 2012. During this short duration i.e. 7 years it has achieved very high power conversion efficiency (PCE) and obtained so many researchers attention. Unfortunately, it has not entered the industry due to some of the demerits such as presence of toxic element lead (Pb), low stability against air ambient and moisture and hysteresis, etc. In this thesis, the attention was on methylammonium lead iodide (MAPbI3) perovskite as the absorber layer of PSC. First, the MAPbI3 was synthesized and studied and then four different elements were introduced to be replaced by lead. In addition, fundamental investigations were done on stability characteristics of each sample. The selected elements used instead of PbI2 in MAPbI3 were zinc iodide (ZnI2), zinc chloride (ZnCl2), potassium iodide (KI) and ruthenium iodide (RuI3). The reason behind selection of Zn, K and Ru were their nontoxic nature, high conductivity, similar ionic radius to Pb and the Schmidt tolerance factor close to 1. The results showed that all the selected materials enhanced the transport properties and PCE of PSC considerably. But, this enhancement was possible when elements partially were replaced with Pb. The good part is that promising results were obtained by introducing Zn to solve the stability issue of MAPbI3. newline