Chalcopyrite compounds/fullerene solar cells based on copper-indium-disulphide and C60 were produced. Two-types of devices with heterojunction and bulk heterojunction structures were examined and characterized. The bulk heterojunction structure provided better efficiency compared to that of the heterojunction structure. Nanostructures of the solar cells were confirmed as mixed nanocrystals by transmission electron microscopy. A photovoltaic mechanism of the present solar cells was discussed on the basis of the experimental results.