Collection Properties of Photovoltaic Fluorescent Systems - Simulations and Experiments

The limits of photovoltaic solar energy conversion by fluorescent collectors are examined theoretically and experimentally. The maximum efficiency of a fluorescent collector corresponds to the Shockley-Queisser limit for a non-concentrating solar cell with a single band gap energy. To achieve this efficiency, the collector requires a photonic structure at its surface that acts as an omnidirectional spectral band stop filter. We find also a high potential of such photonic structures for the improvement of less ideal collector systems involving non-radiative recombination. Analysis of a fluorescent collector system by spatially resolved light induced current measurements and by quantum efficiency analysis shows that the collection efficiency of a real fluorescent collector system increases by up to 30 % with the help of a Bragg stack on top of the collector acting as a band stop filter