- Publisher Summary This chapter explores fullerene thin films as photovoltaic material. Carbon is a unique element existing in a wide variety of stable forms ranging from insulator/semiconducting diamond to metallic graphite. Crystals and thin films of pristine C60 are found to exhibit n-type semiconductor-like behavior in their optical and electronic properties while, at the same time, retaining their molecular character. The chapter reviews structure, properties, and prospects of fullerene thin films for photovoltaics and presents a comprehensive picture of the state-of-the-art and future directions of fullerene-based solar cell research. Special attention is paid to the excitonic mechanism of photogeneration in these devices that requires a sophisticated nanostructural engineering of fullerene-based photovoltaic materials and devices compromising the requirements of thin photo-active layers with an effective light absorption, photogeneration, and transport of free carriers. Examples of device architecture that may satisfy these challenging requirements include fullerene/amorphous carbon multiheterojunctions and quantum wells, fullerene/conjugated polymer bulk heterojunctions with controlled morphology, “double-cable” donor-acceptor systems, fullerene/phthalocyanine p–i–n single and multijunctions, carbon nanotube, and quantum dots based solar cells. Efficiencies of 5% have now been reported. Based on current trends efficiency up to 10% appears to be within reach in the near future.