Tailoring halide perovskite materials CsTmX ₃ (X=F, Cl, Br, I) for enhanced optoelectronic and thermoelectric characteristics through first-principles investigations

Perovskite materials have exquisite characteristics and applications in the field of optoelectronics and thermoelectricity. We have studied here exhaustively the structural, electronic, optical and thermoelectric properties of CsTmX 3 ([Formula: see text], Cl, Br, I) halide perovskite for the first time through a DFT-based study. The structures of all compounds are well optimized. In this work, the optoelectronic behavior is assessed by the following two potential functionals, PBE and TB-mBJ, and also TB-mBJ accompanied by Spin Orbit Coupling (SOC). The compounds CsTmF 3 and CsTmBr 3 exhibit metallic behavior within the PBE framework, whereas TB-mBJ and TB-[Formula: see text] predict semiconducting behavior for all compounds. Similarly, in the band formation, the roles of d-states of Cs and Tm, while f and p-states of Tm and X site atoms, respectively, are ostensible. From the optical studies, these materials are confirmed to be applicable for optoelectronic shielding purposes in the high-energy regime. Furthermore, the thermoelectric aspect of the aforesaid compounds in the form of Seebeck coefficient, electrical conductivity, thermal conductivity and thermoelectric figure of merit is measured. Due to their bonzer thermoelectric character and optimized carriers’ concentrations, these materials are considered to be good contenders for thermoelectric applications.