Concentrator bifacial Ag-free LGCells

Abstract

Results obtained for the bifacial low concentrator Ag free Cz silicon solar cells based on Indium–Tin–Oxide(ITO)/(p+nn+)Cz–Si/Indium–Fluorine–Oxide (IFO) structure (“n-type” cell) as well as on IFO/(n+pp+)Cz–Si/ITO structure (“p-type” cell) are presented in this work. The (p+nn+)Cz–Si and (n+pp+)Cz–Si structures were produced by diffusion of boron and phosphorus from deposited B- and P-containing glasses followed by an etch-back step. The n+ surface of the structures was textured, whereas the p+ surface remained planar. Transparent Conducting Oxide (TCO) films, which act as antireflection electrodes, were deposited by ultrasonic spray pyrolysis method on both sides. The contact pattern of copper wire was attached by the low-temperature (160°C) lamination method simultaneously to the front and rear TCO layers as well as to the interconnecting ribbons arranged outside the structure. The shadowing from the contacts is in the range of ∼4%. The resulting solar cells showed front/rear efficiencies of 18.6–19.0%/14.9–15.3% (“p-type” cell) and 17.3–17.7%/18.1–18.5% (“n-type” cell) respectively at 1–5 suns. At 20–50% albedo of 1-sun illumination, similar energy production corresponds to 21.6–26.8% (n-type cell) and 21.6–26.1% (“p-type” cell) efficiency of a monofacial cell.