A modified drop-casting technique for efficient lead-free, environment-friendly thin film CsBi3I10 perovskite solar cells

Abstract

The efficiency of lead-based perovskite solar cell deteriorates due to their instability and toxicity which inhibits their commercial application. Both of these issues are resolved by substituting Bismuth in place of lead. In order to create environmentally friendly perovskite solar cells (PSCs), bismuth-based halide perovskite (CsBi3I10) is a promising absorber material. Bismuth-based CsBi3I10 perovskite films were fabricated using a modified drop-casting process at room temperature. With this technique, you can get a film with desirable characteristics including a smooth, uniform surface and no pinholes. A comprehensive analysis is carried out in this research article as a result of the fact that thermal annealing is the first step in the process of transforming the deposited solution into the perovskite material. Band gap tuning is achieved with the use of this heat treatment. As film that has been post-annealed at the low temperature of 60 °C is not only tuned in terms of conductivity with a low band gap of 1.78 eV, but it also has improved absorption. In contrast, hexagonal particles with a low absorbance and a greater band gap of 2.08 eV develop at higher post-annealing temperatures. Band gap is greater (2.21 eV) and nonhomogeneous layered structure is formed in the film that does not undergo any post annealing treatment. The effects of post-annealing temperature on morphological, structural, and optical properties are explored and connected with photovoltaic application requirements. Finally, the photovoltaic performance of PSCs based on CsBi3I10 without hole transport layer (HTL) is investigated quantitatively in this study.