"Bulk heterojunctions" from polymers and inorganic molecules or nanoparticles offer simple internal structures for organic photovoltaic cells. Systems proposed so far need quite expensive or instable materials, often with limited availability: open-circuit voltages are well below I V. In this work, a system prepared from poly-3-hexyl-thiophene in contact with ZnS nanoparticles is described. Its almost perfect match of the electronic levels leads to a very high open-circuit voltage, not available until now in similar systems. (C) 2009 Elsevier B.V. All rights reserved.