An enhanced power factor via multilayer growth of Ag-doped skutterudite CoSb3 thin films

Abstract

Skutterudite CoSb₃ has emerged as one of the most studied candidate materials for thermoelectric applications. In this work, the multilayer inter-diffusion method for depositing Ag-doped CoSb₃ thin films was used to improve its thermoelectric property. A microstructure study demonstrates that Ag enters into the lattice. By using first-principles calculations, it can be concluded that the Ag atoms will preferentially occupy the lattice voids, rather than substitute Sb or Co rings, leading to better thermoelectric performance. As expected, the increase of both Seebeck coefficient and electric conductivity is obtained after Ag doping through the multilayer diffusion method, indicating that this approach can resolve the conflict between these often-contractive thermoelectric factors. Due to this efficient combined action, the power factor has substantially been enhanced and the maximum value reaches 0.11 mW m⁻¹ K⁻² at 573 K, which is five times higher than that of the un-doped sample.