Fullerene-based supramolecular nanoclusters with poly[2-methoxy-5-(2'- ethylhexyioxy)-p-phenylenevinylene] for light energy conversion

Organized composite molecular nanoassemblies of fullerene and poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) prepared in acetonitrile/toluene mixed solvent absorb light over the entire spectrum of visible light. The highly colored composite clusters can be assembled as a three-dimensional array onto nanostructured SnO₂ films by electrophoretic deposition approach. The composite cluster films exhibit an incident photon-to-photocurrent efficiency (IPCE) as high as 18%, which is significantly higher than that of a molecular assembly composed of 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)-21H,23H-porphyrin (H₂P) and C₆₀ prepared in the same manner (4%). The maximum IPCE value increases to 25% at an applied bias potential of 0.2V vs saturated calomel reference electrode (SCE). The power conversion efficiency of a MEH-PPV and C₆₀ assembly-modified electrode is determined to be 0.24%. The photocurrent generation properties observed with MEH-PPV and C₆₀ clusters demonstrate the synergy of these systems towards yielding efficient photoinduced charge separation within these composite nanoclusters.