Ultrabroadband and Wide-Angle Hybrid Antireflection Coatings With Nanostructures

Abstract—Ultrabroadband and wide-angle antireflection coat-ings (ARCs) are essential to realizing efficiency gains for state-of-the-art multijunction photovoltaic devices. In this study, we ex-amine a novel design that integrates a nanostructured antireflec-tion layer with a multilayer ARC. Using optical models, we find that this hybrid approach can reduce reflected AM1.5D power by 10–50 W/m2 over a wide angular range compared to conventional thin-film ARCs. A detailed balance model correlates this to an improvement in absolute cell efficiency of 1–2%. Three different ARC designs are fabricated on indium gallium phosphide, and re-flectance is measured to show the benefit of this hybrid approach. Index Terms—Biomimetics, optical films, photovoltaic cells, III–V semiconductor materials. I