Ultrabroadband and Wide-Angle Hybrid Antireflection Coatings With Nanostructures

Ultrabroadband and wide-angle antireflection coatings (ARCs) are essential to realizing efficiency gains for state-of-the-art multijunction photovoltaic devices. In this study, we examine a novel design that integrates a nanostructured antireflection 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 reflectance is measured to show the benefit of this hybrid approach.