Thursday, April 12, 2007

3D Solar Cells Boost Efficiency, Reduce Size and Weight

A team of researchers at the Georgia Tech Research Institute has designed new three-dimensional solar cells that absorb almost all of the light that hits them and could boost the efficiency of photovoltaic (PV) systems while reducing their size, weight and mechanical complexity.

The GTRI photovoltaic cells trap light between their tower structures, which are about 100 microns tall, 40 microns by 40 microns square, 10 microns apart -- and built from arrays containing millions of vertically-aligned carbon nanotubes. Conventional flat solar cells reflect a significant portion of the light that strikes them, reducing the amount of energy they absorb.

Because the tower structures can trap and absorb light received from many different angles, the new cells remain efficient even when the sun is not directly overhead. That could allow them to be used on spacecraft without the mechanical aiming systems that maintain a constant orientation to the sun, reducing weight and complexity – and improving reliability.

The researchers caution that there is still some work to be done on improving the designs. However, at least two efforts to commercialize this technology are already in the works.

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