Fabrication of conductive polymer/inorganic nanoparticles composite films: PEDOT:PSS with exfoliated tin selenide nanosheets for polymer-based thermoelectric devices

Organic polymer based thermoelectric films consisting of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with inorganic tin selenide (SnSe) nanosheets were fabricated. Two-dimensional SnSe nanosheets were prepared by Li intercalation and subsequent exfoliation process from the synthesized bulk ingot. Different amounts of SnSe nanosheets were evenly distributed in the PEDOT:PSS matrix, producing various SnSe/PEDOT:PSS composites. The thermal conductivity of the composites was found to be insensitive to the addition of SnSe nanosheets. The power factor of the composite film was greatly enhanced by the addition of an optimal content of SnSe nanosheets, which significantly increased the Seebeck coefficient, and the solvent treatment, which dramatically improved the electrical conductivity. The maximum power factor of 386 μW/m K2 was obtained for the 5 vol.% dimethyl sulfoxide (DMSO)-treated SnSe/PEDOT:PSS composite film with 20 wt.% of SnSe nanosheet content, which is ∼257 times higher than that of the pristine PEDOT:PSS film. The use of conductive PEDOT:PSS matrix mixed with inorganic SnSe nanosheets and the subsequent solvent treatment appear a promising strategy to achieve high-performance polymer-based thermoelectric devices.