The authors thank the D.M. Rowe and Gao Min (University of Cardiff) for guidelines; Stefano Chiussi (University of Vigo, Spain) for XPS analysis, Dieter Platzek (Panco GmbH, Germany) for Seebeck image map and David Barber (University of Essex) for English amendments. We are also indebted to the Chemistry and Physics departments from University of Aveiro where the Raman scattering experiments were performed and Instituto Tecnológico e Nuclear for RBS/PIXE analysis. ; The optimization of the thermal co-evaporation deposition process for n-type bismuth telluride (Bi2Te3) thin films deposited onto polyimide substrates and intended for thermoelectric applications is reported. The influence of deposition parameters (evaporation rate and substrate temperature) on film composition and thermoelectric properties was studied for optimal thermoelectric performance. Energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy confirmed the formation of Bi2Te3 thin films. Seebeck coefficient (up to 250μV K−1), in-plane electrical resistivity (≈10μΩ m), carrier concentration (3×10^19–20×10^19cm−3) and Hall mobility (80–170 cm2V−1 s−1) were measured at room temperature for selected Bi2Te3 samples.