All-black front surfaces for building-integrated photovoltaics

Abstract

Widespread implementation of building integrating photovoltaics requires aesthetically pleasant panels. Black surfaces are often visually appealing and, if based on a black photoabsorber, may lead to increased panel efficiency. Here, we demonstrate a combination of black silicon and black ribbons (or bus-bars), both fabricated with methods that are compatible with production lines of screen-printed, front contacted solar panels. Maskless, non-cryogenic reactive ion etch of silicon and subsequent coating with aluminum oxide for passivation purposes results in average reflectance of less than 1% in the UV–vis part of the solar spectrum, and in minority carrier lifetimes similar to those obtained on polished reference samples thanks to minimized surface damage, as confirmed by transmission electron microscopy. Inorganic blackening of bus-bars by a combination of electroplating and chemical etching results in reflectance values lower than 3.5% in the UV–vis, with no modifications to standard stringing equipment required.