Effect of Cs partial substitution on crystal systems and bandgap values of MASnCl3

Abstract

The development of Pb-free solar cells is crucial research to reduce the adverse impact of Pb on the environment and people. In this study, we have synthesized MA 1- x Cs x SnCl 3 (MA = CH 3 NH 3 ; x = 0–0.4) via solid-state reaction method. The reduction in lattice parameters and structural phase transition from triclinic to monoclinic at room temperature due to Cs partial substitution was investigated by powder X-ray diffraction (XRD). The reduction in lattice parameters is due to the size difference between MA and Cs. The decrease in the structural phase transition temperature to the cubic phase was revealed by differential scanning calorimetry (DSC). Ultraviolet–visible absorption spectroscopy revealed that bandgap values decrease as the amount of Cs partial substitution increases.