Bismuth telluride (Bi 2 Te 3 ) nanorods (NRs) of n-type thermoelectric materials were prepared using an electrogenerated precursor of tellurium electrode in the presence of Bi 3+ and mercapto protecting agent in aqueous solution under atmosphere condition. The optimal preparation conditions were obtained with ratio of Bi 3+ to mercapto group and Te coulomb by photoluminescence spectra. The mechanism for generation of Bi 2 Te 3 precursor was investigated via the cyclic voltammetry. The highly crystalline rhombohedral structure of as-prepared Bi 2 Te 3 NRs with the shell of Bi 2 S 3 was evaluated with high resolution transmission electron microscopy (HRTEM) and powder X-ray diffraction (XRD) spectroscopy. The near-infrared absorption of synthetic Bi 2 Te 3 NRs was characterized with spectrophotometer to obtain information of electron at interband transition. The thermoelectric performance of Bi 2 Te 3 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 Bi 2 Te 3 nanocrystals was improved by reducing thermal conductivity while maintaining the power factor.