A fluorescent solar collector (FSC) is a waveguide device that can concentrate both diffuse and direct sunlight on to a solar cell. The electrical output of the device depends strongly on the photon fluxes that are absorbed, emitted, and trapped inside the FSC plate. For this reason, it is important to study the photon transport losses inside the collector. One of the losses in FSC to be investigated is scattering, which increases the probability of the escape cone losses. We determine the scattering contributions in FSC by using angle dependence of light internally reflected in the FSC. The cause of scattering in spin-coated polymethylmethacrylate on top of the glass collector is identified as roughness from the top surface, rather than bulk losses. This loss can be suppressed to less than 2% using an index-matching planarization layer.
Fluorescent solar collectors represent an alternative to flat plate photovoltaic arrays. With the emphasis on minimizing
the use of silicon, the collector is usually composed of a mixture of fluorescent dyes embedded in a transparent medium.
The absorbed incoming sunlight is re-emitted at a longer wavelength. A large fraction of fluorescence is totally internally
reflected and transported to the edge of the collector, where the solar cell is placed. The key requirements for efficient
fluorescent collectors are a good photon transport and a broad absorption of sunlight. The fundamental parameter that
determines the efficiency of photon transport is the probability of reabsorption.
Based on experimental results and ray-tracing simulations carried out with "TracePro", this publication illustrates the use
of ray tracing to model reabsorption in collectors with different shapes as well as inhomogeneous structures, and to
assess the validity of the traditional analytical approach. We show that, contrary to expectations, some novel structures
(for example, "thin film" or "waveguide" collectors) do not represent an improvement over their corresponding
homogeneous collectors and that any variation of the film refractive index on a glass substrate leads to an efficiency