Thermoelectric materials based on intermediate phases in the systems formed by chalcogenides of lead and bismuth

The crystal structure and the thermoelectric properties of intermediate phases in the quasibinary systems PbTe-Bi2Te3 and PbSe-Bi2Se3 are studied. The compositions of the compounds of the homologous series [PbTe] m [Bi2Te3] n and [(PbSe)5] m [(Bi2Se3)3] n are identified. The significant difference in quantity, composition, and structure of the intermediate phases in the above two systems is shown. The PbTe-Bi2Te3 system is found to contain a series of tetradymite-like compounds with a trigonal symmetry; the PbSe-Bi2Se3 system is characterized by the formation of compounds with monoclinic lattices of a canizzarite mineral type. A correlation between the behavior of the thermoelectric properties and the crystal structure of the ternary compounds is revealed. The thermoelectric properties of alloys of the solid solutions based on the binary components PbTe, PbSe, and Bi2Te3 are studied.