Three hyperbranched phenylene vinylenes (HPVs)-H-mn, H-es, and H-py-were used in fabricating polymer photovoltaic cells (PVCs). PVCs with photoactive layers composed of pure HPV, a blend of HPV and C-60, and a blend of HPV, poly(2-methoxyl-5,2'-ethylhexyoxyl-1,4-phenylene vinylene) (MEH-PPV), and C-60, were fabricated, and their current-voltage characteristics were measured and investigated. The PVC with photoactive layers composed of H-es and C-60 showed promising photovoltaic characteristics, with an energy-conversion efficiency of 0.035%, when illuminated under 85 mW/cm(2) white light. The short-circuit current and energy-conversion efficiency of the PVCs based on H-mn/C-60 and H-py/C-60 were greatly improved when they were blended with a small amount of MEH-PPV. The incident photon-to-collected-electron efficiency of the HPV/MEH-PPV/C-60 PVCs indicated that both HPVs and MEH-PPV contributed to the photocurrent. (C) 2004 Wiley Periodicals, Inc.