Angular selective backreflector for semitransparent photovoltaics

A nanoporous anodized aluminum oxide template is used as an incident-angle selective backreflector to lift the transparency vs. light absorption tradeoff in semi-transparent photovoltaics. Light incident at angles greater-than 45 degrees from the template normal is backscattered at greater-than 35% intensity to a semitransparent photovoltaic increasing absorption and photocurrent. Meanwhile, light incident orthogonal to the template is transmitted with minimum attenuation (>85% at 600 nm), limited only by a single-pass absorption within the active layer. Using a vertical semitransparent photovoltaic proposed here, efficient capture of direct sunlight is possible while maintaining transparency at viewing angles close to the substrate normal. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4742174]