Nanostructures take the color out of thin-film interference between inner interfaces

May 16, 2013
Raleigh, NC--Inspired (as are many photonics researchers) by the structure of moth eyes, researchers at North Carolina State University (NC State) have developed nanostructures that limit reflection at the interfaces where two thin films meet, suppressing the thin-film interference.

Raleigh, NC--Inspired (as are many photonics researchers) by the structure of moth eyes, researchers at North Carolina State University (NC State) have developed nanostructures that limit reflection at the interfaces where two thin films meet, suppressing the thin-film interference.1 This can potentially improve the efficiency of thin-film solar cells and other optoelectronic devices.

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The NC State nanostructures are built into a thin film that is intended to have a second thin film placed on top of it. The nanostructures are an extension of the thin film beneath them, and resemble a tightly-packed forest of thin cones. These nanostructures are “interfacial,” penetrating into whatever thin film is layered on top of them, limiting the amount of light reflected at the interface between the two films by creating an effective gradient refractive index.

Chih-Hao Chang, an assistant professor of mechanical and aerospace engineering at NC State, and his team found that the interface featuring the interfacial nanostructures reflects 100 times less light than an interface between thin films without the nanostructures.

“Our next steps are to design a solar device that takes advantage of this concept and to determine how we can scale it up for commercial applications,” Chang says.

REFERENCE:

1. Qiaoyin Yang et al., Nanotechnology, May 16, 2013; DOI: 10.1088/0957-4484/24/23/235202.

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

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