Study of detached back reflector designs for thin-film silicon solar cells

Abstract

We present a precise and flexible method to investigate the impact of diverse detached reflector designs on the optical response of p-i-n thin-film silicon solar cells. In this study, the term detached reflectors refers to back reflectors that are separated from the silicon layers by an intermediate rear dielectric of several micrometers. Based on the utilization of a highly conductive n-doped layer and a local electrical contact scheme, the method allows the use of non-conductive rear dielectrics such as air or transparent liquids. With this approach, diverse combinations of back reflector and rear dielectric can be placed behind the same solar cell, providing a direct evaluation of their impact on the device performance. We demonstrate the positive effect of a rear dielectric of low refractive index on the light trapping and compare the performance of solar cells with an air/Ag and a standard ZnO/Ag back reflector design. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.