Improvement in Out-of-plane Conductivity of PEDOT: PSS Thin Films due to Electric Field Treatment at Elevated Temperature

PEDOT: PSS (Poly (3, 4-ethylenedioxythiophene)): (Polystyrene sulfonate) is being widely explored as a buffer layer or charge collecting electrode in many optoelectronic devices. Good out-of-plane electrical conductivity of PEDOT: PSS is prime importance for application in optoelectronic devices such as organic solar cells and light emitting diodes. Enhanced out-of-plane electrical conductivity results in improved device performance. In this article we show an order of magnitude enhancement in out-of-plane electrical conductivity of PEDOT: PSS achieved through electric field treatment of PEDOT: PSS thin films kept at elevated temperature. This change in electrical behavior is due to conformational changes caused by interaction of applied electric field with electrical dipoles associated with the PEDOT: PSS chains. Upon adding DMSO in the PEDOT: PSS solution films show different behavior than when it was not added. Raman and absorption studies confirm the morphological variations induced due to applied electric field.