Cluster-assembled devices for solar energy conversion

The efficiency of solar cells can and needs to be improved, in which nanostructures play an important role. Nanostructures in solar cells are used both for the active layers and for light management techniques. Particularly thin-film solar cells will benefit strongly from such nanoscale approaches as the light absorption needs to be improved. Light management studies that use nanostructures are often created by lithographic methods, which are too expensive for industrial realization. Nanoparticles produced by wet chemical techniques, sometimes in the form of quantum dots, to fabricate thin-film solar cells for research purposes have a limited performance. Nevertheless, there are great opportunities for using nanoparticles as a bottom-up approach for both the active layer and light management nanostructures with the appropriate technique. Since both the wet chemical method and lithographic techniques have considerable limitations, the use of gas aggregation cluster sources is a promising method to advance the use of bottom-up nanoparticles for solar cells. In this chapter Mie scattering and plasmonics are discussed with examples demonstrating the potential of using nanoparticles from a cluster source for solar cells. The increase of solar cell efficiency by using ultraclean and crystalline nanoparticles which are produced with a vacuum-compatible technique at low temperatures should be very interesting for science and technology, ultimately leading to industrial products.