Impact of the Edges of a Backside Diffusive Reflector on the External Quantum Efficiency of Luminescent Solar Concentrators: Experimental and Computational Approach

Luminescent Solar Concentrators (LSCs) have been proposed in the 1970s as cheap planar concentrators for residential applications and nowadays represent a novel idea with excellent perspectives for building integration photovoltaics. The interest in LSCs has increased in the last years, due to improved stability of luminescent dyes, the introduction of quantum dots and nanorods and the overall reported increase in module efficiency. Computational methods have been suddenly applied as an important tool for the description of light dynamics in LSCs. With “raytracing methods” light is described as particle-like (photons) and each particle is tracked. It is precious tool for the description of absorption/reemission events, refraction and internal reflection in LSCs. It is also a very useful approach for the description of LSC edge effects, which may be well described by means of basic geometrical optics and are the subject of this work. The impact of scattering layers on the backside of LSCs is analysed in detail both experimentally and computationally. Results give evidence of the non-wavelength dependent impact of backside diffusers to the external quantum efficiency of LSCs and thus to their overall performance. A possible design of LSC as smart windows in photovoltaic facades is also suggested, where the benefits of the edge effects described are taken into account.