DFT based computational investigations of the physical properties of chalcogenide perovskites CsXS3 (X=P, Ta) for optoelectronic and photovoltaic applications
Md Zillur Rahman, Sayed Sahriar Hasan, Nazifa Absar, Mist Shamima Akter, Md. Akib Hasan, Md. Zahid Hasan, M.A.K. Zilani, Md Ariful Islam
Abstract
In this study, we employed density functional theory (DFT) calculations to systematically characterize the structural, mechanical, electronic, thermal, and optical properties of CsXS₃ (X = P, Ta), one of the most promising members of the chalcogenide perovskite (CP) family. Our theoretical findings align strongly with reported syntheses of other CP's, highlighting CsXS₃ (X = P, Ta) as most stable compounds. These materials satisfy the Born stability criteria, indicating robust mechanical stability, exhibit anisotropy, and demonstrate acceptable resistance to deformation under external stress. CsPS₃ and CsTaS₃ feature direct bandgaps of 1.91 eV and 0.51 eV, with small photocarrier effective masses, high absorption coefficients (1.6 × 10⁶ and 2.1 × 10⁶ cm⁻ 1 ), low reflectivity (15 % and 20 %), reduced loss function (0.6 and 0.4) and low refractive index (2.5 and 3.1), respectively. These properties underscore the potential of CsXS₃ (X = P, Ta)-based CP's for developing more efficient and stable optoelectronic devices and indoor photovoltaics . Notably, CsPS₃ is a strong contender for thermoelectric applications due to its lower Debye temperature compared to other CP's. Overall, our results demonstrate the great promise of CsXS₃ (X = P, Ta) chalcogenide perovskites in advancing the field of renewable energy and optoelectronics .