Effect of incorporation of ethylene glycol into PEDOT: PSS on electron phonon coupling and conductivity

The effect of incorporation of ethylene glycol (EG) into poly(3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS) on electron phonon coupling and conductivity is investigated. It is shown that the carrier density (N-C) increases significantly and the carrier mobility (mu) increases slightly at 300 K. The increased intensity of the Raman spectrum between 1400 and 1450 cm(-1), following EG treatment (that is, the quinoid-dominated structures of the PEDOT chain), leads to an increase in the number of polarons (bipolarons), which leads to an increase in NC. In addition, mu in PEDOT: PSS samples with or without EG addition exhibits a strong temperature dependence, which demonstrates the dominance of tunneling (hopping) at low (high) temperatures. The high conductivity of PEDOT: PSS samples with the addition of EG is attributed to the combined effect of the modification of the electron-phonon coupling and the increase in N-C (mu). (C) 2015 AIP Publishing LLC.