Effect of Annealing on Virgin and Recycled Carbon Fibre Electrochemically-Deposited with N-type Bismuth Telluride

Abstract

N-type thermoelectric bismuth telluride (Bi2Te3) was deposited on virgin carbon fibre (VCF) and recycled carbon fibre (RCF) substrates by electro-deposition. The effects of annealing on the surface morphology and the Seebeck coefficient of the Bi2Te3 films were investigated. A nearly stoichiometric N-type Bi2Te3 was obtained from an electrolyte of 8 mM of Bi(NO3)3.5H2O and 10mM of TeO2, which exhibited the highest Seebeck coefficient of -20.1 µV/K and -13.0 µV/K for VCF and RCF individually. The effect of varying annealing temperature (548.15 K and 623.15 K) and annealing time (2 and 3 h) was carried out only on nearly stoichiometric N-type Bi2Te3 that revealed improvement in Seebeck coefficient up to 1.51 times and 1.24 times for VCF and RCF at 623.15 K for 2 h.