An optimized bilayer solid state solar cell is fabricated from poly[ 1,4-12-methoxy-5(2'-ethylhexyloxy) 1, phenylenevinylene] (MEH-PPV) and TiO2 by spin coating. Optimal and reproducible device performance has been achieved by adjusting the polymer/TiO2 layer thickness, fabricating devices under an inert atmosphere and improving the polymer/ gold contact. These devices showed very small leakage currents in the dark and an open circuit voltage of 0.8 V was recorded. The effect of interfacial properties, incident light intensity and irradiation time on device performance are also discussed. (c) 2005 Elsevier B.V. All rights reserved.