Facile synthesis and thermoelectric studies of n-type bismuth telluride nanorods with cathodic stripping Te electrode

Bismuth telluride (Bi2Te3) nanorods (NRs) of n-type thermoelectric materials were prepared using an electrogenerated precursor of tellurium electrode in the presence of Bi3+ and mercapto protecting agent in aqueous solution under atmosphere condition. The optimal preparation conditions were obtained with ratio of Bi3+ to mercapto group and Te coulomb by photoluminescence spectra. The mechanism for generation of Bi2Te3 precursor was investigated via the cyclic voltammetry. The highly crystalline rhombohedral structure of as-prepared Bi2Te3 NRs with the shell of Bi2S3 was evaluated with high resolution transmission electron microscopy (HRTEM) and powder X-ray diffraction (XRD) spectroscopy. The near-infrared absorption of synthetic Bi2Te3 NRs was characterized with spectrophotometer to obtain information of electron at interband transition. The thermoelectric performance of Bi2Te3 NRs was assessed with the result of electrical resistivity, Seebeck coefficient, thermal conductivity, and the figure of merit ZT parameters, indicating that thermoelectric performance of as-prepared Bi2Te3 nanocrystals was improved by reducing thermal conductivity while maintaining the power factor.