Designing and prototyping the polyhedral specular reflector, a spectrum-splitting module with projected >50% efficiency

Abstract

We investigate a spectrum-splitting design, the polyhedral specular reflector, for an ultra-high efficiency module (>50%). The design employs a series of multilayer dielectric stack filters to divide the incident spectrum onto seven independently connected subcells. We optimized the geometry and components of the design through coupled wave-optics, device physics, electrical circuit, and ray tracing models. We show a wide design space where >50% module efficiencies are possible and have chosen a design with a projected 50.8% module efficiency to prototype. Initial efforts show excellent matching of the fabricated optical splitting prism (90.1% splitting efficiency) to the theoretical design (93% splitting efficiency). Additionally, integrating fabricated concentrators yields an optical structure consistent with a 30% efficiency module.