Incorporation of Stokes shifting dyes into a Si-based photovoltaic thermal system

In this article, a novel photovoltaic/thermal (PV/T) geometry is introduced that allows for passive microlensing, IR collection, and photovoltaic deployment, as in previous implementations, together with spectral splitting. Stokes shifting dyes of the Coumarin family were dispersed in a thermal fluid in front of a single-junction amorphous silicon PV using a tubular focusing geometry. This architecture effectively shifts the high-energy UV flux into near bandgap photons for the Si, while capturing the released energy of the Stokes transition as heat. By combining this with the thermal fluid’s IR absorption and the PV, the system converts a surprising amount of the solar flux into collectable power, with a 71.05% thermal conversion efficiency and 2.07% electrical efficiency, leading to a total system efficiency of conversion of 73.1 percent. Temperatures and heat flow were then simulated to connect optical characteristics to thermal transport characteristics and allow for optimization under various circumstances. Impact statement The large entry cost of solar makes it unattainable for large segments of the world’s population. In this article, we present a photovoltaic/thermal (PV/T) system, made of low-cost, easily accessible materials that are simple to manufacture. Together, the components of the system harvest energy from nearly the entire solar spectrum using a photovoltaic, infrared absorbing thermal fluid and a Stokes shifting dye. The geometry of the PV/T acts as a passive microlens system while providing the additional benefit of keeping the PV cool. The modeling presented allows for optimization in specific applications. Graphical abstract