Correlation of morphology and charge transport in poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT-PSS) films

A wide variation in the charge transport properties of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) films is attributed to the degree of phase-segregation of the excess insulating polyanion. The results indicate that the charge transport in PEDOT-PSS can vary from hopping to critical regime of the metal-insulator transition, depending on the subtle details of morphology. The extent of electrical-connectivity in films, directly obtained from a temperature dependent high-frequency transport study, indicates various limiting factors to the transport, which are correlated with the phase separation process. The low temperature magnetotransport further supports this morphology-dependent transport scenario.