Electronic and Optical Properties of Cl-doped CH₃NH₃SnI₃ Perovskite: A DFT Study

¹ Laboratory of Engineering in Chemistry and Physics of Matter (LICPM), Faculty of Sciences and Technics, Sultan Moulay Slimane University, BP 523, 23000 Beni Mellal, Morocco
² Research Laboratory in Physics and Sciences for Engineers (LRPSI), Poly-disciplinary Faculty, Sultan Moulay Slimane University, BP 592, 23000 Beni Mellal, Morocco
³ UNESCO UNISA Africa Chair in Nanosciences & Nanotechnology (U2ACN2), College of Graduate Studies, University of South Africa (UNISA), Pretoria, South Africa
⁴ PSES, ERC, Ecole Normale Supérieure, Mohammed V University in Rabat P. O. Box: BP5118 Takkadoum Rabat - 10000, Morocco

^* Abdelmounaim Laassouli: abdelmounaim.laassouli@gmail.com

Abstract

Organic-inorganic hybrid perovskites have emerged as promising materials for photovoltaic applications. This study investigates the impact of chlorine (Cl) doping on the electronic and optical properties of the perovskite CH₃NH₃SnI₃ (MA-SnI₃) using density functional theory (DFT) calculations. We explore Cl doping concentrations of 8.33%, 16.66%, and 25%, analyzing the resulting changes in bandgap, density of states, and absorption coefficient. DFT calculations reveal a significant reduction in the bandgap with increasing Cl concentration, shifting from 1.055 eV for the methylammonium tin iodide structure to 0.727 eV, 0.731 eV, and 0.792 eV for the doped structures, respectively. Analysis of the density of states highlights the influence of Cl on the electronic structure. Furthermore, the absorption coefficient increases within the visible range, suggesting enhanced light absorption capabilities. Our results are consistent with experimental observations, validating the accuracy of DFT as a tool for studying Cl-doped MA-SnI₃ perovskites and providing insights into their potential for solar cell applications.