Unveiling role of exchange-correlation functions in investigating physical properties of CsMnCl3 perovskite for optoelectronic applications

Metal halide perovskites have garnered significant attention for their transformative applications in photovoltaics , optoelectronics , and photocatalysis . This study pioneers an in-depth examination of the structural, electronic, elastic, mechanical, and optical properties of CsMnCl 3 perovskite using GGA-PBE and GGA + U calculations with diverse exchange-correlation functionals (PBE, RPBE, PW91, WC, and PBEsol) within the CASTEP code. The structural parameters of CsMnCl 3 perovskite are substantially affected by the exchange-correlation function, particularly the lattice constants , which exhibit functional-dependent variations. The material demonstrates metallic properties under GGA-PBE, while it manifests semiconductor behavior with an indirect energy bandgap energy (R→G) under other functionals GGA + U with PBE, RPBE, PW91, WC, and PBEsol. Notably, the calculated energy bandgaps exhibit functional-specific variations: 1.956 eV (GGA + U-PBE), 2.041 eV (GGA + U-RPBE), 1.994 eV (GGA + U-PW91), 1.890 eV (GGA + U-WC), and 1.895 eV (GGA + U-PBEsol). The compound shows low reflectivity , a large absorption coefficient value, and good optical conductivity in the visible region. Moreover, the Born stability criterion suggests that material is mechanically stable, and ductile according to Poisson scale/Pugh's ratio. It has an anisotropic nature according to the anisotropy index. These exceptional results advocate its suitability for flexible optoelectronic applications. • Exchange-correlation functionals impact the lattice parameters, stability, and electronic properties. • GGA-PBE underestimate the bandgap energy value of the CsMnCl 3 Perovskite. • Suitable optical properties : low reflectivity , high absorption coefficient, and good optical conductivity in the visible region suggest potential applications in optoelectronic devices. • The compound is mechanically stable, ductile, and anisotropic.