Study of charge transfer mechanism and dielectric relaxation of all-inorganic perovskite CsSnCl3

Abstract

In the field of commercialization, lead-free metal halide perovskite materials are becoming more popular these days because of their prospective use in solar cells and also in other optoelectronic applications. In this paper, a non-toxic CsSnCl₃ metal halide is successfully synthesized via the slow evaporation solution growth technique. Such systematic characterizations as differential scanning calorimetry (DSC) measurements, dielectric measurements, and variable-temperature structural analyses indicate that CsSnCl₃ goes through a reversible phase transformation at T = 391/393 K from the monoclinic to the cubic system. Optical measurements of CsSnCl₃ reveal a direct band-gap value of about 3.04 eV. The study of the charge transfer mechanism of CsSnCl₃ is carried out based on Elliott's theory. The conduction mechanism in CsSnCl₃ is interpreted through the following two approaches: the non-overlapping small polaron tunneling (NSPT) model (monoclinic phase) and the overlapping large polaron tunneling (OLPT) model (cubic phase). Moreover, the high dielectric constant of CsSnCl₃ which is associated with a low dielectric loss makes it a possible candidate for energy harvesting devices.