SNAPSUN, a 3-year project funded by the EU's Seventh Framework Programme (FP7), aims at developping an innovative nanocomposite material for solar cell applications.

Nanotechnologies show broad opportunities to reduce the cost and increase the efficiency of solar cells. Indeed, at the nanoscale level, the energy band gap depends on the nanomaterial architecture (nanoparticle size, bulk dispersion, interfaces with embedding matrix). Thus silicon nanoparticles allow the design of highly efficient photovoltaic devices, like multijunction solar cells or low-cost, optimised, thin-film solar cells.

However, the usual elaboration technique of silicon nanoparticles is based on the deposition of multilayers in which excess silicon is aggregated into nanoparticles through high temperature annealing. With this conventional technique, control of nanoparticle size and bulk dispersion is difficult. Moreover, only limited host matrix materials can be considered. This prevents any knowledge-based tuning of the nanomaterial properties.

The main objective of the SNAPSUN project is to develop a novel nanomaterial with reliable and tailored characteristics, by achieving accurate control over silicon nanoparticle and host matrix properties.

To overcome the limitations of the conventional technique for elaboration of silicon nanoparticles, control of material structure will arise from the development of very promising processes allowing the separation of silicon nanoparticle generation and host matrix codeposition. Fully tailored silicon nanoparticles will be optimised, in terms of size and size dispersion. These silicon nanoparticles will be incorporated into a wide band gap host matrix, such as silicon carbide or transparent conductive oxides. This new architecture will allow band gap engineering through accurate structure control, together with exceptional electrical characteristics (resistivity, carrier lifetime, etc.) in order to produce high photovoltaic efficiencies above 25%.

With the support of the EU's Seventh Framework Programme (FP7)    EU