Organic solar cells were fabricated by spray deposition of highly conductive PEDOT:PSS. Both PEDOT:PSS (Clevios PH750) and an active layer were spray deposited by the substrate heating method. In order to improve the conductivity of spray-deposited PEDOT:PSS, DMF or DMSO was added to it. As a result, surface morphology of PEDOT:PSS with DMSO-(/DMF) changed and its conductivity improved by about 10,000 times that of pure PEDOT:PSS. Solar cells fabricated using spray-deposited DMSO-added PEDOT:PSS as a transport layer showed a power conversion efficiency (PCE) of similar to 3%, an open voltage of 0.62 V. and a short circuit current of 14.02 mA/cm(2). Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.