High thermoelectric performance in ZnSb-SnTe pseudo-binary materials

Abstract We examine the insulation–metal transition (IMT) behavior that occurs during dynamic phase-change processes in ZnSb-SnTe materials. This behavior can contribute to abnormally high thermoelectric performance, originating from IMT characteristics that regulate electrical transport. The 27.3 at% SnTe-doping reduces the phase transition temperature to approximately 214°C and realizes IMT in (ZnSb)72.7(SnTe)27.3 films. When a phase transition occurs, Sn atoms diffuse into ZnSb to form SnSb nano-crystallites within an amorphous matrix. This phase exhibits a typical IMT with dynamic critical characteristics accompanied by large fluctuations in chemical composition, nucleation modes, and phase boundaries. Hence, the nanoprecipitates formation and crystallization transition occurs in the nanocomposite structure. These features strongly influence carrier density and markedly improve electrical conductivity to retain the Seebeck coefficient, thereby leading to a high power factor of 3383 μWm–1K–2 at 300°C. Thus, (ZnSb)72.7(SnTe)27.3 is a robust thermoelectric candidate for energy conversion applications in low and moderate temperature ranges.