Ann Steffora Mutschler, Senior Editor -- Electronic Business, 10/4/2007, taken from EDN

To help solar cells catch more of the sun's rays, researchers guided by the National Science Foundation have created an anti-reflective coating that allows light to travel through it, but lets almost none bounce off its surface.

The coating material is made of silica nanorods and is at least 10 times more effective than the coating on sunglasses or computer monitors, and may be used to channel light into solar cells or allow more photons to surge through the surface of a light-emitting diode (LED), the researchers said.

Jong Kyu Kim and a team from Rensselaer Polytechnic Institute in Troy, New York crafted the coating, which reflects almost as little light as do molecules of air, guided by National Science Foundation-supported electrical engineer Fred Schubert.

The researchers developed a process based on an already common method for depositing layers of silica, the building block of quartz, onto computer chips and other surfaces, which grows ranks of nanoscale rods that lie at the same angle. The degree of the angle is determined by temperature. Under a microscope, the films look like tiny slices of shag carpet.

By laying down multiple layers, each at a different angle, the researchers noted that they created thin films that are uniquely capable of controlling light, and with the right layers in the right configuration, they believe they can even create a film that will reflect no light at all.

The key application for this material is in the development of next-generation solar cells.

By preventing reflections, the coating would allow more light, and more wavelengths of light, to transmit through the protective finish on a solar cell surface and into the cell itself so that engineers could use the technique to boost the amount of energy a cell can collect, bypassing current efficiency limits.