The overall objective of the project is to develop new Nanomaterials with New Production Technologies and to fabricate silicon quantum dot tandem solar cells to achieve increased efficiencies. The understanding of electrical transport and recombination mechanisms in these newly developed nanomaterials will enable us to design new tandem solar cell structures - based on Si thin-film or wafer solar cells - that help to overcome the efficiency limits of these conventional concepts. In order to reach our goals, considerable R+D work has to be performed on semiconductor bulk materials, thin layers and hetero-structures for such solar cells. These topics have not yet or only in parts been investigated and are also of high scientific interest for novel photonic and charge storage devices incorporating Si nanocrystals embedded in Si alloys. The consortium of this project, also including two companies, merges the scientific and technological competences that are necessary to find answers to these questions. Another objective is the compatibility of the newly developed technologies with high-throughput processing to ensure further cost-reduction. The expected significant jump in the solar cell and processing evolution will lead to higher efficiencies for solar cells and to ongoing cost-reduction also with a long-term perspective and will help to strengthening the European leadership in PV technologies. Thus it will also have a positive impact on the acceptance of photovoltaics by the public and by politics. Moreover, since “energy efficiency” is a big subject in the public discussion, photovoltaics will be an example of one of the highest electricity production efficiencies that have been achieved of all power generators. To sum up, we believe that this project will have a direct and positive impact on the European PV industry and its status in material science and it will contribute to the very ambitious goals of the EU commission in CO2 reduction in general.