3D solar cells capture more sunlight, boost solar panel efficiency

Tuesday, July 24, 2007 by: David Gutierrez, staff writer
Tags: solar panels, solar technology, health news

(NewsTarget) Scientists at the Georgia Tech Research Institute (GTRI) have developed a prototype of a three-dimensional solar panel that is able to capture sunlight from nearly every angle and transform it into electricity, according to a report in the journal JOM, which is published by the Minerals, Metals and Materials Society. According to researchers, the new cell should be vastly more efficient than current photovoltaic panels.

Current photovoltaic cells are made in the shape of flat panels. This means that sunlight must strike the panels directly, and that light falling at the wrong angle is not collected. In addition, flat panels reflect a significant portion of the light that hits them, making it unavailable for electricity generation.

The new panels make use of nanotechnology, and are shaped much like a city skyscape -- a collection of tower-like structures with small spaces between them. To the naked eye or even a regular microscope, the panels still appear flat; the "towers" are on the scale of microns, or millionths of a meter. This unique shape allows the towers to collect light from nearly any angle.

The towers are squares about 40 microns on a side, 100 microns tall and 10 microns apart.

This unique shape increases the panels' efficiency for yet another reason. All solar panels have a coating that is designed to trap photons (light particles) rather than reflect them. The thicker the coating, the more photons trapped. However, thicker coatings also reduce the speed at which current-carrying electrons exit the panel, thus reducing its efficiency. Because the new panels capture more light, the coating can be made thinner and thus a single panel can generate more current.

"Our goal is to harvest every last photon that is available to our cells," said Jud Ready, a senior research engineer at GTRI's Electro-Optical Systems Laboratory.

The research was sponsored by the Air Force Office of Scientific Research, the Air Force Research Laboratory, NewCyte Inc., and Intellectual Property Partners, LLC. The next step for researchers is to see if the two-inch prototype can be adapted for mass-production.