DFT-Material Parameters and SCAPS-1D Simulation of Lead-Free CsSnCl₃ Perovskite Solar Cells

Abstract

We investigated the electronic structure behavior and optical response of CsSnCl3 inorganic perovskite with density functional theory (DFT). The goal was to check if it can work well in solar cells. The results show CsSnCl3 have a semiconductor behavior with direct band gap of about 1.93 eV. This value means the material absorbs visible light strongly. Optically, the compound has a high absorption coefficient, around 105cm-1. It also has a decent dielectric constant and refractive index. Because of this, it interacts well with light. From the DFT runs we pulled out the main parameters: The band gap (Eg), electron affinity (χ), dielectric constant (εr), effective densities of states in the conduction and valence bands (N_C, N_V), electron and hole mobilities (µ_e, µ_h), and absorption coefficient α(ω). All of them went into SCAPS-1D as inputs. The resulting model for a cell with CsSnCl3 as absorber gave good numbers. For an ITO/ETL(IGZO)/Absorber (CsSnCl3)/HTL(Cu2O)/Au architecture, the simulated cell achieved a Power Conversion Efficiency (PCE) was about 15.65%, With Short-Circuit Current Density, Jsc = 12.41mA/cm2, Open-Circuit Voltage, Voc = 1.51 V, and fill Factor, FF = 83.60%. In short, CsSnCl3 looks non-toxic and it could be a solid option for perovskite PV devices.