Facile MWCNTs-SnSe/PEDOT:PSS ternary composite flexible thermoelectric films optimized by cold-pressing

Flexible composite films with high power factors are the candidate for wearable energy harvesters, MWCNTs-SnSe/PEDOT:PSS ternary composite films were fabricated by a vacuum filtration method. The effects of cold-pressing on morphology, Raman spectra, and thermoelectric (TE) properties of the composite films were studied. For cold-pressed MSPPD10 ternary composite film, its conductivity and Seebeck coefficient both increase with increasing temperature. The results show that the PF is enhanced to 166.5 μW m⁻¹ K⁻² for the cold-pressed MSPPD10 ternary composite film, which is 2.8 times the MSPPD10 (59.35 μW m⁻¹ K⁻²) composite film without cold-pressing treatment. Besides, the TE property of cold-pressed MSPPD10 ternary composite film is better than that of SnSe or MWCNTs combined with PEDOT:PSS. The cold-pressed MSPPD10 ternary composite film had excellent flexibility, and the resistance only increases 12% after 1000 bends on an iron rod with a radius of 4 mm. In addition, the TE generator consisting of 4-leg cold-pressed MSPPD10 ternary composite films has a maximum output power of 13.5 nW at a temperature gradient of 30 K, showing great potential for flexible TE applications.