A Zn-doped Sb2Te3 flexible thin film with decoupled Seebeck coefficient and electrical conductivity via band engineering

Abstract

Sb₂Te₃-based flexible thin films can be utilized in the fabrication of self-powered wearable devices due to their huge potential in thermoelectric performance. Although doping can significantly enhance the power factor value, the process of identifying suitable dopants is typically accompanied by numerous repeating experiments. Herein, we introduce Zn doping into thermally diffused p-type Sb₂Te₃ flexible thin films with a candidate dopant validated using the first-principles calculations. Subsequent experiments further corroborated the successful introduction of a Zn dopant and the improvement of thermoelectric performance. Specifically, p-type doping and the increase in the calculated effective mass can significantly increase the Seebeck coefficient, achieving the decoupling of the Seebeck coefficient and electrical conductivity in Sb₂Te₃ flexible thin films. An outstanding power factor of ∼22.93 μW cm⁻¹ K⁻² at room temperature can be obtained in the 0.58% Zn doped Sb₂Te₃ sample with significant flexibility. The subsequent fabrication of a flexible thermoelectric generator provides the maximum output voltage and output power of ∼53.0 mV and ∼1100 nW with a temperature difference of 40 K, respectively, pointing out the huge potential of Zn-doped Sb₂Te₃ materials for thermoelectric applications in self-powered wearable devices.