High-Performance MoS2/SWCNT Composite Films for a Flexible Thermoelectric Power Generator.

Abstract

Single-walled carbon nanotube (SWCNT)-based thermoelectric materials have been extensively studied in the field of flexible wearable devices due to their high flexibility and excellent electrical conductivity (σ). However, poor Seebeck coefficient (S) and high thermal conductivity limit their thermoelectric application. In this work, free-standing MoS2/SWCNT composite films with improved thermoelectric performance were fabricated by doping SWCNTs with MoS2 nanosheets. The results demonstrated that the energy filtering effect at the MoS2/SWCNT interface increased the S of composites. In addition, the σ of composites was also improved due to the reason that S-π interaction between MoS2 and SWCNTs made good contact between MoS2 and SWCNTs and improved carrier transport. Finally, the obtained MoS2/SWCNT showed a maximum power factor of 131.9 ± 4.5 μW m-1 K-2 at room temperature with a σ of 680 ± 6.7 S cm-1 and an S of 44.0 ± 1.7 μV K-1 at a MoS2/SWCNT mass ratio of 15:100. As a demonstration, a thermoelectric device composed of three pairs of p-n junctions was prepared, which exhibited a maximum output power of 0.43 μW at a temperature gradient of 50 K. Therefore, this work offers a simple method of enhancing the thermoelectric properties of SWCNT-based materials.