Enhanced Seebeck Coefficient of Cu-Bi-S Heterogeneous Composite Synthesized via Solvothermal Method

Abstract

We report on a heterogeneous composite Cu-Bi-S system for thermoelectric applications. This composite was synthesized by an efficient solvothermal method. The dominant phase of Cu3BiS3 showed a weak polymorphic nature at room temperature. The low polymorphic to first-order phase transition was obtained at 391.5 K where the carriers dominated the transport properties. The structure changed from P212121 to modulated intermediate polymorphic continues up to 463 K followed by changes to high polymorph. The ionic conduction switched in the intermediate modulate structure above 408 K. The phase boundary scattering mechanism was attributed to the enhancement of the Seebeck coefficient. The maximum power factor of 2.76 μWm−1K−2 at 443 K persisted in this heterogeneous composite where Cu3BiS3 phase existed as an intermediate polymorph.