Photon management in two-dimensional disordered media

Given the ever-growing demand of green energy, many efforts of the industrialized societies are spent in the development of new technologies for renewable energy. In particular, the nanophotonic community has been producing a great deal of alternative strategies to improve the performance of various photovoltaic technologies. Thin-film solar cells are the current state-of-the-art in solar energy technologies, made out of different, sometimes very expensive, materials (e.g. CdTe, CIGS), for which nanophotonics is particularly suited for improving their performance. These so-called third-generation solar cells generally have high quantum efficiency, thereby yielding more electric current per absorbed photon. However, given the small thickness of the film (less than 1 μm), the probability for a photon to be absorbed is low, yielding a small net production of electric current, in spite of high quantum efficiencies. Nanophotonics aims to find reliable solutions to enhance the absorption of light in thin films. Engineering the absorbing material at the nanoscale indeed leads to interferences that can significantly increase light absorption [1,2].