First-Principles Study of Dopant-Induced Structural, Electronic and Thermoelectric Properties of RbSnX3 Perovskites

Abstract

This work reports a comprehensive first-principles investigation of the structural, electronic, and thermoelectric properties of RbSnX₃ (X = Cl, Br, I) halide perovskites. Structural stability is confirmed through formation energy and elastic criteria, satisfying mechanical stability conditions. Electronic structure calculations reveal direct bandgap semiconducting behavior, with bandgaps decreasing systematically from Cl to I due to enhanced orbital interactions. Thermoelectric properties are evaluated within the Boltzmann transport framework. The results indicate high Seebeck coefficients, moderate electrical conductivity, and low lattice thermal conductivity, which collectively enhance thermoelectric efficiency. The dimensionless figure of merit (ZT) exhibits significant improvement with increasing temperature, reaching optimal values at elevated conditions. Among the studied compounds, RbSnI₃ demonstrates superior performance due to its favorable carrier transport properties. These findings suggest that RbSnX₃ perovskites are promising lead-free candidates for thermoelectric energy conversion applications.