Toward a theoretical limit of solar cell efficiency with light trapping and sub-structure

Abstract

The performances of Si − n + − p solar cells are calculated using the cell width as a parameter and taking into account light trapping effect and infrared light excitation due to the inclusion of a defect layer near the n − p junction. A model is developed to describe light confinement and optimized cell structures are considered. The low absorption of long wavelength photons in thin solar cells is shown to be compensated by the light confinement. Higher values of the maximum output power are obtained and the effect is particularly significant for thin base cells ( H < 60 μm) with a 3.5 mW cm −2 maximal increase of the maximum output power.