Contrasting role of antimony and bismuth dopants on the thermoelectric performance of lead selenide

摘要

Increasing the conversion efficiency of thermoelectric materials is a key scientific driver behind a worldwide effort to enable heat to electricity power generation at competitive cost. Here we report an increased performance for antimony-doped lead selenide with a thermoelectric figure of merit of ~1.5 at 800?K. This is in sharp contrast to bismuth doped lead selenide , which reaches a figure of merit of ?1?K?2 at temperatures above 400?K. The addition of small amounts (~0.25?mol%) of antimony generates extensive nanoscale precipitates, whereas comparable amounts of bismuth results in very few or no precipitates. The antimony-rich precipitates are endotaxial in lead selenide , and appear remarkably effective in reducing the lattice thermal conductivity. The corresponding bismuth-containing samples exhibit smaller reduction in lattice thermal conductivity.