High-mobility PbSe crystals with trace Sb doping for wide-temperature thermoelectric applications

Abstract

We challenge the conventional design paradigm by demonstrating that light doping in single crystals can more effectively enhance the average ZT. A large-sized PbSe single crystal lightly doped with Sb was successfully grown via physical vapor deposition. By eliminating grain-boundary and point-defect scattering, the PbSb_0.001Se crystal achieves a high electron mobility of 1,050 cm² V⁻¹ s⁻¹ and a moderate carrier concentration of 1 × 10¹⁹ cm⁻³ at room temperature. This significantly improves thermoelectric performance over a wide temperature range. The optimized sample was fabricated into a 7-pair cooling device, achieving a temperature difference of 49 K at room temperature. Additionally, a single-leg device demonstrated a power generation efficiency of 8%. These results highlight how lightly doped single crystals provide a promising pathway to achieving high average ZT, making PbSe a competitive Te-free candidate for efficient thermoelectric cooling and power generation.