Photon collection efficiency of fluorescent collectors is examined experimentally and by modelling, with a view to assess the potential of this attractive solar energy technology. The edge fluorescence of single dye collectors based on Rhodamine 6G and Coumarin 540A, manufactured by a simple fabrication technique, is investigated in detail. A novel technique for determination of the collection efficiency is presented based on the traditional model of fluorescent collectors but extended to allow spectral analysis. We show that these results agree well with direct solar cell measurements. General conclusions are presented about fundamental loss mechanisms and about the role of re-absorption of fluorescent light. It is shown that substantial improvements in collector efficiency can be made with the use of photonic fluorescence confinement rather than by total internal reflection.