A low concentration approach to spectral splitting optics for bifacial 4-T modules

The present work introduces the conceptual design of the optics for a spectral-splitting and light-guiding photovoltaic (PV) four-terminal (4T) module with appealing features for bifacial operation. The geometry here described performs low-gain 2D concentration in the visible (VIS) spectrum and can couple a Si solar cell to a wide-bandgap (WG) one. We analyze and discuss the conditions of applicability of the solution from the optical viewpoint. The performance analysis has been performed using commercial ray-tracing software (ZEMAX OpticStudio), by admitting direct and isotropically diffused solar irradiation at standard AM1.5G spectrum.