Highly Conductive Poly(3,4-Ethylenedioxythiophene): Poly (Styr Enesulfonate) (Pedot: PSS) Films and Their Application in Polymer Photovoltaic Devices

Abstract

New transparent conductive materials are urgently needed to replace indium tin oxide (ITO) as the transparent electrode of optoelectronic devices. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a quite promising candidate as the next-generation transparent electrode in optoelectronic devices. However, as-prepared PEDOT:PSS from its aqueous solution suffers a problem of low conductivity of <1 S/cm. It is important to significant enhance the conductivity of PEDOT:PSS. In this thesis, four novel methods have been developed to significantly enhance the conductivity of PEDOT:PSS film: (1) salt treatment; (2) zwitterion treatment; (3) acid treatment; and (4) cosolvent treatment. Conductivity enhancement by a factor of about 1000 was observed. The mechanism for the conductivity enhancement was attributed to the departure of PSSH from the PEDOT:PSS films and the conformational change of the PEDOT chains during the treatment. The application of these highly conductive PEDOT:PSS films as the transparent electrode of polymer photovoltaic cells (PVs) have been demonstrated.