Enhanced thermoelectric performance of reduced graphene oxide incorporated bismuth-antimony-telluride by lattice thermal conductivity reduction

We investigate the thermoelectric properties of reduced graphene oxide (RGO) incorporated Bi0.36Sb1.64Te3 composites. A melt spinning process enables RGO to be uniformly distributed with Bi0.36Sb1.64Te3 matrix and the incorporated RGO increases the carrier mobility of Bi0.36Sb1.64Te3 matrix with the enhancement of the power factor by 20%. The grain sizes of the Bi0.36Sb1.64Te3 materials decrease with the RGO amount, leading to the reduction in lattice thermal conductivity by enhancing grain boundary scattering. Owing to the above effects, the thermoelectric figure of merit (ZT) can be enhanced in the measured temperature range, where the optimum ZT value is reached to 1.16 at 393 K, ∼15% higher ZT value than pristine Bi0.36Sb1.64Te3. Consequently, this RGO incorporation method could be widely used to improve thermoelectric performances in other conventional thermoelectric materials. •The single step synthesis of reduced graphene oxide/Bi0.36Sb1.64Te3 composites is proposed.•The enhanced thermoelectric properties are obtained by incorporating reduced graphene oxide in Bi0.36Sb1.64Te3.•The reduced graphene oxide prevents the matrix diffusion during the sintering process in order to reduce BST grain size.•The reduced graphene oxide in Bi0.36Sb1.64Te3 provides an increment of charge carrier mobility.