Investigation of the photovoltaic properties of BaHf1-xZrxS3 ([formula omitted]) chalcogenide perovskites using first principles calculations

Abstract

Electronic, optical, and photovoltaic properties of BaHf1-xZrxS3 (x = 0.00, 0.25, 0.50, 0.75, and 1.00) alloys were evaluated using first principles calculations via the density functional theory. The exchange-correlation potential is treated with generalized gradient approximation. Additionally, the Tran–Blaha modified Becke–Johnson exchange potential is employed, because it gives very accurate results of the band gap in solids. The band structure calculations reveal that these compounds exhibit a semiconductor behavior with a small band gap (Eg < 2 eV). To investigate the optical transitions in these compounds, the real and imaginary parts of the dielectric function are examined. The coefficient absorption (α) is calculated and discussed as well. We found a remarkable α exceeding 105 cm−1 near Eg, which is suitable for the absorption of visible light. To exploit the high photo-absorptivity and evaluate the photovoltaic performance of these alloys, the power conversion efficiency is computed using the spectroscopic limited maximum efficiency method. Our predicted alloys have the characteristics required for photovoltaic applications with a maximum photovoltaic efficiency (η) between 22.22% and 30.09% for thickness L = 500 nm. Particularly, BaHf0.75Zr0·25S3 reveals a performance comparable to that of the best-known photovoltaic materials such as CH3NH3PbI3.