In the present work, we have studied photovoltaic devices fabricated from a blend of regioregular poly (3-hexlthiophene) (P3HT) and Buckminster fullerene. The solvent and composite ratio have been selected to obtain best morphology and minimum degradation. Buffer layers of poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate) (PEDOT:PSS) at the anode and of LiF at the cathode were used to improve the device performance. It was further found that post-annealing of the devices for an optimum duration and temperature improves the solar cells, and the power conversion efficiency of the devices increases to 2.1% at AM 1.5. Though the efficiency using [6,6]-phenyl C60 butyric acid methyl ester (PCBM) as the composite acceptor instead Of C60 can be higher, it was not used because of its very high cost as compared to C-60. (C) 2007 Elsevier B.V. All rights reserved.