Thermoelectric Characteristics of Self-Supporting WSe₂-Nanosheet/PEDOT-Nanowire Composite Films

Conducting polymer poly(3,4-ethylenedioxythiophene) nanowires (PEDOT NWs) were synthesized by a modified self-assembled micellar soft-template method, followed by fabrication by vacuum filtration of self-supporting exfoliated WSe₂-nanosheet (NS)/PEDOT-NW composite films. The results showed that as the mass fractions of WSe₂ NSs increased from 0 to 20 wt % in the composite films, the electrical conductivity of the samples decreased from ∼1700 to ∼400 S cm^-1, and the Seebeck coefficient increased from 12.3 to 23.1 μV K^-1 at 300 K. A room-temperature power factor of 44.5 μW m^-1 K^-2 was achieved at 300 K for the sample containing 5 wt % WSe₂ NSs, and a power factor of 67.3 μW m^-1 K^-2 was obtained at 380 K. The composite film containing 5 wt % WSe₂ NSs was mechanically flexible, as shown by its resistance change ratio of 7.1% after bending for 500 cycles at a bending radius of 4 mm. A flexible thermoelectric (TE) power generator containing four TE legs could generate an output power of 52.1 nW at a temperature difference of 28.5 K, corresponding to a power density of ∼0.33 W/m². This work demonstrates that the fabrication of inorganic nanosheet/organic nanowire TE composites is an approach to improve the TE properties of conducting polymers.