Efficient and Stable Perovskite Solar Cell with TiO2 Thin Insulator Layer as Electron Transport

Organic–inorganic metal halide perovskite solar cells (PSCs) have been attracted much attention due to their intense broad–band absorption, high charge carrier mobility, low–cost precursor materials and simple solution processing and the impressive upsurge in their solar to electric power conversion efficiency (PCE) over the last few years. An optimized layer structure of PSC with a very thin TiO2 as electron transport layer has been proposed. The optimized PSC shows the highest efficiency ever reported in this system. Insertion of a very thin TiO2 beneath the perovskite material enhances efficiency significantly. However, efficiency has been drastically declined while TiO2 is used on the perovskite material. The role of TiO2 has been studied and the mechanism has also been explained using established formalism. This study has implication to design further efficient and stable PSC to meet energy crisis.