Anti-reflection coatings of zero-index metamaterial for solar cells

Anti-reflection coatings of zero index metamaterials (ZIMs) are proposed for maximum absorption of light in solar cells. A thin layer of a ZIM is shown to help trap light inside a solar cell. The outer surface of a ZIM layer is planar, and the inner surface has periodic corrugations in order for the incident light to pass through but block the re-transmission of the light back into free space. Using rigorous calculations for light absorption efficiency integrated over the AM1.5 solar spectrum, the basic design of the anti-reflection coating using a ZIM is studied by comparing the results with a common anti-reflection coating and a ZIM layer planar on both sides.