Ionic Liquids as Post-Treatment Agents for Simultaneous Improvement of Seebeck Coefficient and Electrical Conductivity in PEDOT:PSS Films.

Ionic liquid (IL) post-treatment for thin films of poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is employed for the simultaneous enhancement of Seebeck coefficients and electrical conductivities. Through systematic variation of the ILs, by changing the anions while keeping the cation unchanged, changes in thermoelectric, spectroscopic, and morphological properties are investigated by means of UV-vis spectroscopy and grazing-incidence wide-angle X-ray scattering (GIWAXS) as a function of the IL concentration. The simultaneous enhancement in the two important thermoelectric properties is ascribed to the binary nature of the ILs, which complements that of PEDOT:PSS.