Electrical properties of polymer photovoltaic cells using pentacene-doped PEDOT: PSS as a hole conducting layer

The performance characteristics of polymer photovoltaic cells, in which the pentacene-doped PEDOT:PSS thin films are used as a hole conducting layer, have been investigated and characterized by employing AFM, SEM, UV-visible, work function and current density-voltage analysis. Pentacene-doped PEDOT:PSS was prepared by blending pentacene with 1-methy1-2-pyrrolidinone (NMP) and PEDOT:PSS in solution. By using NMP as a solvent, pentacene as a dopant was introduced into PEDOT:PSS films. The surface roughness of PEDOT:PSS films was increased, and aggregate boundaries were clearly distinguished. Pentacene might form aggregations with PEDOT:PSS during the film forming process. UV-visible transmission intensity also increased as doping percent of pentacene increased. The work function of pentacene-doped PEDOT:PSS film decreased by approximately 0.3 eV, and this may contribute to moving holes easily toward ITO substrate. Consequently, pentacene-doped PEDOT:PSS film as a hole conducting layer leads to improving the performance characteristics of photovoltaic cells. Copyright (C) 2012 John Wiley & Sons, Ltd.