PUB-2016-EHT

Enhanced high temperature thermoelectric response of sulphuric acid treated conducting polymer thin films

S. R. Sarath Kumar, Narendra Kurra and H. N. Alshareef, "Enhanced high temperature thermoelectric response of sulphuric acid treated conducting polymer thin films"
​J. Mater. Chem. C, 2016, 4, 215--221
S. R. Sarath Kumar, Narendra Kurra and H. N. Alshareef
high temperature; thermoelectric
2016
We report the high temperature thermoelectric properties of solution processed untreated and sulphuric acid treated poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (or PEDOT:PSS) films. The acid treatment is shown to simultaneously enhance the electrical conductivity and the Seebeck coefficient of the metal-like films, resulting in a five-fold increase in the thermoelectric power factor (from 0.01 to 0.052 W m−1 K−1) at 460 K, compared to the untreated film. By using atomic force micrographs, Raman and impedance spectra and using a series heterogeneous model for electrical conductivity, we demonstrate that acid treatment results in the removal of PSS from the films, leading to the quenching of accumulated charge-induced energy barriers, facilitating metal-like conduction. The continuous removal of PSS and changes in morphology of the PEDOT grains upon acid treatment may alter the local band structure of PEDOT:PSS, in such a way as to simultaneously enhance the Seebeck coefficient.