CsMBi₃Te₆ and CsM₂Bi₃Te₇ (M = Pb, Sn): New Thermoelectric Compounds with Low-Dimensional Structures

The new materials CsPbBi3Te6 nad CsPb2Bi3Te7 were discovered through reactions of CsBi4Te6 with PbTe, whereas the isostructural materials CsSnBi3Te6 and CsSn2Bi3Te7 were discovered through corresponding reactions with SnTe. The compounds can also be prepared from stoichiometric mixtures of Cs2Te, Pb (Sn), Bi, and Te. The crystal structures show a layered architecture of NaCl-type slabs alternating with layers of Cs atoms. This group of compounds offers a new quaternary system, Cs−M−Bi−Te (M = Pb and Sn), available for thermoelectric investigations, including fine-tuning of compositions and doping.