Mechanical Stability and Energy Gap Evolution in Cs-Based Ag, Bi Halide Double Perovskites under High Pressure: A Theoretical DFT Approach.

Autor: Parrey ID; Science Faculty, Department of Physics, Pamukkale University, Denizli 20160, Türkiye., Bilican F; Science Faculty, Department of Physics, Pamukkale University, Denizli 20160, Türkiye., Kursun C; Department of Physics, Faculty of Sciences, Kahramanmaras Sutcu Imam University, Kahramanmaras 46040, Turkey., Kart HH; Science Faculty, Department of Physics, Aydın Adnan Menderes University, Aydın 09010, Türkiye., Parrey KA; Department of Physics, Faculty of Sciences, Kahramanmaras Sutcu Imam University, Kahramanmaras 46040, Turkey.; Faculty of Natural Science, Department of Physics, Jamia Millia Islamia, New Delhi 110025, India.
Jazyk: angličtina
Zdroj: ACS omega [ACS Omega] 2023 Jul 12; Vol. 8 (29), pp. 26577-26589. Date of Electronic Publication: 2023 Jul 12 (Print Publication: 2023).
DOI: 10.1021/acsomega.3c03469
Abstrakt: Due to their intrinsic stability and reduced toxicity, lead-free halide double perovskite semiconductors have become potential alternatives to lead-based perovskites. In the present study, we used density functional theory simulations to investigate the mechanical stability and band gap evolution of double perovskites Cs 2 AgBiX 6 (X = Cl and Br) under an applied pressure. To investigate the pressure-dependent properties, the hydrostatic pressure induced was in the range of 0-100 GPa. The mechanical behaviors indicated that the materials under study are both ductile and mechanically stable and that the induced pressure enhances the ductility. As a result of the induced pressure, the covalent bonds transformed into metallic bonds with a reduction in bond lengths. Electronic properties, energy bands, and electronic density of states were obtained with the hybrid HSE06 functional, including spin-orbit coupling (HSE06 + SOC) calculations. The electronic structure study revealed that Cs 2 AgBiX 6 samples behave as X-Γ indirect gap semiconductors, and the gap reduces with the applied pressure. The pressure-driven samples ultimately transform from the semiconductor to a metallic phase at the given pressure range. Also, the calculations demonstrated that the applied pressure and spin-orbit coupling of the states pushed VBM and CBM toward the Fermi level which caused the evolution of the band gap. The relationship between the structure and band gap demonstrates the potential for designing lead-free inorganic perovskites for optoelectronic applications, including solar cells as well as X-ray detectors.
Competing Interests: The authors declare no competing financial interest.
(© 2023 The Authors. Published by American Chemical Society.)
Databáze: MEDLINE
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