Morphology and fluorescence quenching in photovoltaic samples containing fullerene and poly (p-phenylene-vinylene) derivatives

We have studied the morphology of different heterogeneous samples containing poly [2-methoxy,5-(3',7'-dimethyl-octyloxy)]-p-phenylene-vinylene (MDMO-PPV) and either fullerene (C(60)) or 6,6-phenyl C(61)-butyric acid methyl ester (PCBM) using atomic force microscopy in the shear force detection mode or pulsed-force mode and near-field scanning optical microscopy. These investigations confirm the large influence of preparation conditions on the morphology. Systematic variation of the layer thicknesses in two-layer samples indicate that fluoresecence quenching is restricted to ail interface layer with a thickness of about 40 nm. (C) 2003 Published by Elsevier B.V