Nanostructuring has successfully enhanced thermoelectric performance for wide solid-state materials via embedding nano-scale particles, precipitates, or dislocations into the matrix to significantly lower the thermal conductivity. Herein, high-density dislocations are successfully introduced through engineering the off-stoichiometry ratio of cation atoms in Pb1-xSe. As examined by electron microscopy characterizations and phonon transport modeling studies, the existence of dense nano-scale dislocations in conjunction with grain boundaries and point defects lead to the strong wide-frequency phonon scatterings. Consequently, lattice thermal conductivity is significantly decreased in Pb1-xSe. Through doping In into the Pb0.96Se with an ultralow lattice thermal conductivity, the carrier concentration is tuned to reach the optimal level, which is confirmed by our modeling investigations. The synergistically obtained high-density of dislocations and the optimized carrier concentration lead to an extraordinary figure-of-merit of 1.6 in n-type Pb0.96-yInySe. This study demonstrates a natural way to induce high-density nano-scale dislocations by self-vacancy engineering, which extends the strategy of nanostructuring to broader materials for developing high-performance thermoelectric candidates.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)
- Electrical and Electronic Engineering