Post-Electric Current Treatment Approaching High-Performance Flexible n-Type Bi₂Te₃ Thin Films

Inorganic n-type Bi2Te3 flexible thin film, as a promising near-room temperature thermoelectric material, has attracted extensive research interest and application potentials. In this work, to further improve the thermoelectric performance of flexible Bi2Te3 thin films, a post-electric current treatment is employed. It is found that increasing the electric current leads to increased carrier concentration and electric conductivity from 1874 S cm−1 to 2240 S cm−1. Consequently, a high power factor of ~10.70 μW cm−1 K−2 at room temperature can be achieved in the Bi2Te3 flexible thin films treated by the electric current of 0.5 A, which is competitive among flexible n-type Bi2Te3 thin films. Besides, the small change of relative resistance <10% before and after bending test demonstrates excellent bending resistance of as-prepared flexible Bi2Te3 films. A flexible device composed of 4 n-type legs generates an open circuit voltage of ~7.96 mV and an output power of 24.78 nW at a temperature difference of ~35 K. Our study indicates that post-electric current treatment is an effective method in boosting the electrical performance of flexible Bi2Te3 thin films.