Electrodeposition of Bi ₂ Te ₃ and Bi ₂ Te ₃ /reduced GO thin film thermoelectric materials in dimethyl sulphoxide

In this paper, the redox behaviour of Bi(III) unitary, Te(IV) unitary, Bi(III)-Te(IV) (Bi-Te) binary and Bi(III)-Te(IV)-graphene oxide (Bi-Te-GO) ternary solution using dimethyl sulphoxide as solvent was analysed by cyclic voltammetry and linear sweep voltammetry. On this basis, Bi2Te3 and Bi2Te3/reduced graphene oxide(Bi2Te3/rGO) thermoelectric thin films were prepared by potentiostatic electrodeposition. The phase structure, microstructure, elemental composition and thermoelectric properties of the composites were characterised by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer and Seebeck coefficient tests. The results show that the redox processes of Bi(III) unitary, Te(IV) unitary, Bi-Te binary and Bi-Te-GO ternary solution in DMSO are all irreversible. The reduction of Bi(III) ions is more difficult than that of Te(IV) ions, but at a certain potential, co-reduction of Bi(III) ions, Te(IV) ions and GO can occur. The surface roughness of the prepared thin film thermoelectric material increases with the negative shift of the deposition potential. The Bi2Te3 and Bi2Te3/rGO film materials prepared at different potentials all exhibit P-type characteristics, with the highest Seebeck coefficient of about 29.7 μV K−1.