Thermoelectric properties of cation-substituted solid solutions based on layered tetradymite-like compounds

Abstract

It is shown that isovalent cation substitutions in the Ge(Bi 1 - xSbx)4Te7 (0 < x < 1) and Pb1 - xSnxBi4Te7 (0 < x < 1) solid-solution systems ensure a markedly reduced lattice thermal conductivity in comparison with the constituent ternary chalcogenides. In the Ge(Bi 1 - xSbx)4Te7 system, increasing the Sb content leads to a conversion from n- top-type. Cu-doped PbBi 4 - xCdxTe7 solid solutions (heterovalent substitution) are n-type and surpass PbBi4Te7 in the thermoelectric figure of merit.