Power factor enhancement via simultaneous improvement of electrical conductivity and Seebeck coefficient in tellurium nanowires/reduced graphene oxide flexible thermoelectric films

• Water-processable reduced graphene oxide (RGO)/Te nanowires thermoelectric films were prepared.
• The redox reaction between the RGO and Te nanowires were confirmed by XRD, SEM, TEM, Raman and XPS.
• The simultaneous improvement of electrical conductivity and Seebeck coefficient were realized in the hybrid films.
• Transport characteristics in RGO/Te hybrid films were discussed.

The simultaneous improvement of electrical conductivity (σ) and Seebeck coefficient (S) is essential to realize the thermoelectric materials with high power factor value. Here, we report the discovery that the redox reaction happened between the reduced graphene oxide (RGO) sheets and tellurium (Te) nanowires can lead to a simultaneous improvement of σ and S in the RGO/Te nanowires hybrid films. With optimization, the electrical conductivity and Seebeck coefficient can reach 633 S/m and 382 μV/K, respectively, pushing the power factor value up to 68.4 μW/(mK2), approximately 25 times larger than the reported pure Te nanowires film. Based on all of the characterizations, the redox reaction between the RGO sheets and Te nanowires have been confirmed and the transportation characteristics of the hybrid films are predicted. We demonstrate the new approach that via turning the redox reaction, the interfacial interaction can be optimized, enabling a novel flexible thermoelectric films with superior performance. To our knowledge, this is the first time that the TE properties of RGO/inorganic hybrid films are reported.