Exploring the physical properties of Rb 2 TlSbM 6 (M = Cl, Br) inorganic halide perovskites for solar cell applications: A DFT study

We studied Rb 2 TlSbM 6 (M = Cl, Br) halides using density functional theory calculations to determine their potential thermoelectric and optoelectronic properties. The stability of cubic phase halides was analyzed through Goldsmith ' s tolerance factor and enthalpy of formation calculations. By analyzing the electronic characteristics, the bandgap of Rb 2 TlSbCl 6 (E g = 1 .713 eV ) and Rb 2 TlSbBr 6 (E g = 1 .713 eV ) were calculated with GGA-PBE potentials for improved accuracy and comparison with reported values. The high absorption coefficient of Rb 2 TlSbM 6 (M = Cl, Br) perovskite halides in the ultraviolet spectrum and low reflectivity in the order of 20 % make them promising for optoelectronics and photovoltaic applications. The Poisson and Pugh ratio calculations suggested the ductile nature of these materials. The Boltz-TraP code was employed to investigate the thermoelectric properties of Rb 2 TlSbM 6 (M = Cl, Br) perovskites within the temperature range of (200 - 850 K). The findings demonstrate that Rb 2 TlSbM 6 (M = Cl, Br) is a promising candidate for thermoelectric applications based on its exceptional thermoelectric properties. The SLME analysis performed on Rb 2 TlSbCl 6 and Rb 2 TlSbBr 6 at 293 K indicates an SLME of 31.04 % and 27.53 %, respectively. This finding suggests that these materials have great potential for utilization in solar cells.