LiPbSb3S6: A semiconducting sulfosalt with very low thermal conductivity

Abstract

The new semiconductor LiPbSb3S6 crystallizes in the space group P21/c. The structure is a member of the lillianite homologous series and is composed of layers of PbS archetype Sb/Li-S separated by trigonal-prismatic-coordinated Pb/Li. Electronic band structure calculations indicate an indirect band gap, with direct gaps lying very close in energy. LiPbSb3S6 has one of the lowest thermal conductivities seen in a crystalline material, ∼0.24 W m-1 K-1 at room temperature, and a high resistivity, ∼4 × 109 Ωcm, and exhibits strong light absorption with a nearly direct band gap of 1.6 eV. © 2014 American Chemical Society.