Recent advances in SnTe-based thermoelectric materials: Synthesis, band engineering, and performance optimization

Abstract

Tin telluride (SnTe) has gained renewed attention as a sustainable alternative to lead-based thermoelectrics for mid-temperature waste-heat recovery. Its rock-salt structure, high carrier mobility, and suitable band structure make it an attractive candidate; however, the high intrinsic hole concentration and relatively high lattice thermal conductivity limit its figure of merit (ZT). In recent years, significant progress has been made through strategies such as aliovalent doping, alloying, band convergence, and microstructural engineering to improve its thermoelectric efficiency. This review summarizes key developments in the synthesis and optimization of SnTe-based materials prepared by melt growth, mechanical alloying, solution processing, and spark plasma sintering. Emphasis is placed on the correlation between synthesis conditions, resulting defect chemistry, and their influence on carrier concentration, Seebeck coefficient, and lattice thermal conductivity. Recent advances, including multi-doping, nanoscale precipitate formation, and defect-controlled phonon scattering, are critically examined to highlight their impact on transport properties. The review concludes with an outlook on scalable synthesis, long-term stability, and future opportunities for achieving high-performance, lead-free SnTe thermoelectrics suitable for practical energy-harvesting applications.