Electrodeposition of Bi₂Te₃ thin films for thermoelectric applications: effect of electrolyte pH

Modern materials like Bi2Te3 nanostructures are one of the most promising thermoelectric materials since they show a high value of the thermoelectric figure of merit. This paper reports the effect of electrolyte pH (in a low pH range starting from 0.25 to 1.50) on the structural, electrochemical, and thermoelectric properties of the electrodeposited Bi2Te3 films. Two of the samples showed significantly high values of Seebeck coefficient (49.28 mu V/T and 45.26 mu V/T, respectively), which are comparable to the Si (42 mu V/T), SiC nanowires (40 mu V/T), and Ge (47 mu V/T) thermoelectric materials. Also, the observed crystallinity and electrochemical behavior are in agreement with the thermoelectric results for electrodeposited Bi2Te3 films. In nutshell, a lower range of pH of electrolytes has been found to be a significant control parameter in the present study. Such Plausible tailoring of properties would be helpful for the systematic study of complex and multi-composite materials for various applications.