Solvent treatment of wet-spinning PEDOT:PSS fiber towards wearable thermoelectric energy harvesting

Abstract Wearable energy supply nowadays gains great interest due to a sharp increase in demand for highly flexible, stretchable and embedded electronics, where fiber-based thermoelectric (TE) energy harvesting is a competitive counterpart compared with other energy supply systems. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) fiber has been prepared with wet-spinning method. However, the conductivity of the pristine PEDOT:PSS fiber is poor. Herein, PEDOT:PSS fibers were treated with different solvents to remove the insulative PSS chains and improve the conductivity of the fibers. In particular, the fiber sequential treated with EG and H2SO4 (EG-H2SO4) displayed an improved conductivity of 676.59 S cm−1. Therefore, the optimized PEDOT:PSS fibers achieved a power factor of 9.42 μWm−1 K−2 with a slightly reduced Seebeck coefficient. Finally, a simple fiber TE device was assembled based on the optimized PEDOT:PSS fiber with an output voltage of 1.7 mV. This work can supply an effective technique for preparing and regulating chemical composition for wearable energy harvesting.