Experimental demonstration of a dispersive spectral splitting concentrator for high efficiency photovoltaics

We report the experimental demonstration of a low-cost paradigm for photovoltaic power generation that utilizes a prismatic Fresnel-like lens to simultaneously concentrate and separate sunlight into laterally spaced spectral bands. The optical element is designed using geometric optics and optical dispersion and its performance is simulated with a ray-tracing software. The device, fabricated by injection molding, suitable for large-scale mass production, is experimentally characterized. We report an average optical transmittance above 85% over the VIS-IR range and spectral separation in excellent agreement with our simulations. Finally, the system is tested with a pair of copper indium gallium selenide based solar cells. We demonstrate an increase in peak electrical power output of 160% under outdoor sunlight illumination, corresponding to an increase in power conversion efficiency of 15% relative to single-junction full-spectrum one-sun illumination. Given the ease of manufacturability and the potential of the proposed solution, we project that our design can provide a cost-effective alternative to multi-junction solar cells ready for mass production.