Integrated hydrothermal-green approach to synthesize Fe, Ag doped copper sulfide nanopowders and investigations of their thermoelectric properties

Abstract

Copper sulfide and Fe, Ag doped copper sulfide nanopowders were synthesized by integrated hydrothermal-green approach, using Urtica dioica leaf extract as a solvent. With Fe and Ag doping, covellite as the major phase was sustained but reduction in crystallite size and change in morphology was observed. Decrease in electrical conductivity from ∼186.24 Scm−1 for undoped copper sulfide to ∼34.97 Scm−1 and ∼23.26 Scm−1 on doping Fe and Ag, respectively, at 300 K, was witnessed due to formation of different phases of copper sulfide and incorporation/segregation of Ag/Fe into copper sulfide lattice. Conversely, Seebeck coefficient showed enhanced values on doping Fe and Ag. The maximum power factor of ∼22.22 μW/mK2 was found for undoped copper sulfide. Thus, the incorporation/segregation of Fe/Ag ions in copper sulfide lattice and grain boundaries was found to alter the thermoelectric performance of copper sulfide.