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 (X = F, Cl, Br, I) halide perovskite for the first time through DFT based study. The structures of all compounds are well optimized. In this work, the optoelectronic behavior is assessed by 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-mBJ+SOC 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 in the 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 contender for thermoelectric applications.