Solar Energy Materials & Solar Cells 90 (2006) 3531–3546 Photovoltaic activity of a PolyProDOT derivative in a bulk heterojunction solar cell Luis M. Campos a,Ã , Attila J. Mozer b , Serap Gu¨nes b , Christoph Winder b , Helmut Neugebauer b , N. Serdar Sariciftci b , Barry C. Thompson c , Benjamin D. Reeves c , Christophe R.G. Grenier c , John R. Reynolds c a Department of Chemistry & Biochemistry and Exotic Materials Institute, University of California, Los Angeles, CA 90095-1569, USA b Linz Institute for Organic Solar Cells (LIOS) Physical Chemistry, Johannes Kepler University Linz, Altenbergerstrasse 69, A-4040 Linz, Austria c The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry and Center for Macromolecular Science and Engineering, University of Florida, Gainesville, FL 32611-7200, USA Received 18 March 2006; received in revised form 13 June 2006; accepted 14 June 2006 Available online 17 August 2006 Abstract We report the photophysical behavior and photovoltaic performance of a poly(3,4-propylene- dioxythiophene) (PProDOT) derivative, namely poly-[3,3-dihexyl-3,4-dihydro-2H-thieno(3,4- b)(1,4)dioxepine] (PProDOT(Hx) 2 ), as an electron donor in bulk heterojunction solar cells blended with the acceptor 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methanofullerene (PCBM). Devices composed of a 1:4 (w:w) ratio of PProDOT(Hx) 2 /PCBM and spin coated from chlorobenzene were characterized by measuring current–voltage characteristics under simulated Air Mass 1.5 (AM1.5) conditions as well as the spectrally resolved photocurrent (IPCE). The influence of different preparation parameters like various blend ratios, spin coating from different solvents, and changing the metal contacts was studied. It was found that the photoluminescence of the polymer is quenched by a factor greater than 100 using blends consisting of PProDOT(Hx) 2 and PCBM (3:2, w:w). Additionally, the photoactive blends were characterized by photoinduced absorption spectroscopy and the results suggest that charge transfer is occurring from PProDOT(Hx) 2 to PCBM. Results ARTICLE IN PRESS www.elsevier.com/locate/solmat 0927-0248/$ - see front matter r 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.solmat.2006.06.051 Ã Corresponding author. E-mail address: lcampos@chem.ucla.edu (L.M. Campos).