Investigating structural and electronic features, band gap modulation, and optical absorption in ASnCl₃ (A = Na, K) perovskites for optoelectronic applications

Abstract

This study uses density functional theory (DFT) within the WIEN2k computational framework to explore the structural, elastic, and optoelectronic properties of cubic perovskite compounds ASnCl₃ (A = Na, K). The findings align well with earlier theoretical and experimental studies, confirming the cubic symmetry and structural stability of both materials. Elastic constants were calculated to verify their mechanical stability, revealing that both compounds are ductile and suitable for practical applications. The electronic band structure analysis shows direct band gaps of 1.462 eV for NaSnCl₃ and 0.825 eV for KSnCl₃, suggesting their potential as efficient semiconductors. These properties make them promising candidates for use in electronic and optoelectronic devices. Additionally, the optical properties were analyzed by calculating the absorption spectra over a photon energy range of 0–10 eV. The results indicate excellent absorption and reflectance characteristics, particularly in the visible and ultraviolet regions. This makes ASnCl₃ (A = Na, K) highly suitable for next-generation solar cells and advanced optoelectronic technologies.