Light trapping in silicon-film (TM) solar cells with rear pigmented dielectric reflectors

This paper presents the novel method of using pigmented dielectric reflecto rs to provide light trapping in thin-film silicon solar cells. This type of reflecting material offers many potential advantages over specular metalli c reflectors, including low cost, compatibility with high temperatures comm on to solar cell processing, and high, broadband and diffuse reflectance, A s this is the first time this concept is described, the basic theory of the optical behavior of pigmented materials is presented by connecting the bas ic material properties of pigment and medium to their light trapping benefi t in thin silicon solar cells. Several general principles Lading to maximum light-trapping benefit are identified and experimental evidence is present ed corroborating these general principles. Light trapping is demonstrated i n thin silicon solar cells with pigmented dielectric reflectors by measurem ent and analysis of external quantum efficiency curves. Copyright (C) 1999 John Wiley & Sons, Ltd.