Design of broadband SOG fresnel lens for GaInP/GaInAs/Ge multi-junction concentrator solar cells

Abstract

In this paper, we designed a novel kind of broadband SOG Fresnel lens special for GaInP/GaInAs/Ge multijunction concentrator solar cells. In the broadband spectrum of 350-1800 nm, every subcell's spectral response characteristic and the dispersion relation of the material's refractive index with wavelengths were taken into consideration. Each saw-tooth's surface profile of Fresnel lens was optimized by finding its design main wavelength. In contrast to conventional Fresnel lens concentrators, this design improves the irradiance uniformity without the complicated theoretical approaches. Finally, the uniformity of illumination intensity and the optical efficiency more than 80% were achieved.