Prediction of Ruddlesden–Popper Antiperovskites K<sub>4</sub>OBr<sub>2</sub> and K<sub>4</sub>OI<sub>2</sub> for Potential Thermoelectric Application
Yong‐Jie Hu, Shuai Zhao, Lin Chen
Abstract
The escalating global energy demands and environmental concerns have intensified the pursuit of efficient thermoelectric materials that convert waste heat into electrical energy. This study focuses on Ruddlesden–Popper potassium oxyhalide antiperovskites, K 4 OBr 2 and K 4 OI 2, as potential thermoelectric candidates. Through first-principles calculations, we comprehensively investigated their structural stability, electronic band structures, electronic transport properties, and thermal conductivity. These materials exhibit anisotropic carrier mobility and high Seebeck coefficients, which are attributed to their unique electronic band structures and effective mass distributions. The power factor, a key determinant of thermoelectric performance, shows a temperature-dependent trend with maxima achieved at specific carrier concentrations. Lattice thermal conductivity, a critical parameter for thermoelectric efficiency, is found to be significantly lower than that of other reported antiperovskites, due to the presence of avoided crossings in phonon dispersions, which enhance phonon scattering. Our calculations predict that figures of merit of these thermoelectric materials can be optimized to over 1.5 at high carrier concentrations and elevated temperatures, highlighting their potential for thermoelectric applications. These results can serve as a theoretical guide for exploring novel, lightweight, and low-cost thermoelectric materials.