Electrodeposition of antimony from chloride-free ethylene glycol solutions and fabrication of thermoelectric Bi2Te3/(Bi1−xSbx)2Te3 multilayers using pulsed potential electrodeposition

Abstract

The electrochemical behavior of antimony in chloride-free ethylene glycol and the electrodeposition of antimony-bismuth and antimony-tellurium binary alloys, and bismuth-antimony-tellurium ternary alloys from ethylene glycol solutions were investigated by means of cyclic voltammetry (CV), electrochemical quartz crystal microbalance (EQCM) and rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) experiments. It was found that antimony(III), tellurium(IV) and bismuth(III) have comparable diffusion coefficients in ethylene glycol. The electrodeposition potential of antimony was more negative than that of tellurium and the alloy deposition obeyed regular alloy deposition behavior. In the ternary alloy deposition experiments, only a bismuth-telluride alloy could be electrodeposited at low overpotentials and the antimony content in the alloy increased when more negative potentials were applied or when lower rotation speeds were used. Bi2Te3/(Bi1−xSbx)2Te3 multilayers were obtained by alternating the electrodeposition potentials using a rotating disk electrode. During the deposition of antimony by reduction of antimony(III) in ethylene glycol, “explosive” antimony was probably formed.