Theoretical limits for visibly transparent photovoltaics

Transparent photovoltaics (PVs) provide a potentially facile route to building-integrated PVs and seamless energy-harvesting within non-window surfaces such as electronic displays, autonomously powered electronic-glazings, and mobile-electronic accessories. Such devices have been enabled by manipulation of excitons in organic and molecular semiconductors that allow for selective ultraviolet and near-infrared solar conversion. Here, the theoretical efficiency limits of transparent photovoltaics are determined as a function of transparency. Power-production from ultraviolet and near-infrared photons alone leads to a theoretical single-junction efficiency of 21% in transparent structures, compared to 33% for opaque-junctions. Reducing thermal losses via transparent multi-junction stacking these limits increase to 37%. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4738896]