Demonstration of a novel dispersive spectral splitting optical element for cost- effective photovoltaic conversion

Abstract: In this letter we report the preliminary validation of a low-cost paradigm for photovoltaic power generation that utilizes a prismatic Fresnel-like lens to simultaneously concentrate and separate sunlight into continuous laterally spaced spectral bands, which are then fed into spectrally matched single-junction photovoltaic cells. A prismatic lens was designed using geometric optics and the dispersive properties of the employed material, and its performance was simulated with a ray- tracing software. After device optimization, it was fabricated by injection molding, suitable for large-scale mass production. We report an average optical transmittance of ~ 90% over the VNIR range with spectral separation in excellent agreement with our simulations. Finally, two prototype systems were tested: one with GaAsP and c-Si photovoltaic devices and one with a pair of copper indium gallium selenide based solar cells. The systems demonstrated an increase in peak electrical power output of 51% and 64% respectively under white light illumination. Given the ease of manufacturability of the proposed device, the reported spectral splitting approach provides a cost- effective alternative to multi-junction solar cells for efficient light-to-electricity conversion ready for mass production.