Hybrid TiO2:polymer photovoltaic cells were made from mixtures of titanium(IV) isopropoxide and poly [2-methoxy-5-(3',7'-dimethyloetyl)-p-phenylene vinylene] (MDMO-PPV) or poly(3-octyl thiophene) (P3OT) via hydrolysis in air. Cells were made with varying titanium(IV) isopropoxide: polymer ratios. Current-voltage measurements (at 0.7-0.8 sun equivalent) of a TiO2:P3OT (10 vol.% TiO2) photovoltaic cell show a short-circuit current of 0.7 mA/cm(2), an open-circuit voltage of 450 mV and a fill factor of 0.41, resulting in a calculated AM L5 (100 mW/cm(2)) power conversion efficiency of 0.17%. Devices based on MDMO-PPV and TiO2 (20 vol.% TiO2) show an open-circuit voltage of 600 mV and a short-circuit current of 0.6 mA/cm(2) (at 0.7 sun equivalent), resulting in a calculated AM1.5 power conversion efficiency of 0.22%. (C) 2003 Elsevier B.V. All rights reserved.