Science / Medicine : New Solar Battery Developed

Photovoltaic cells that convert 31% of the energy in sunlight into electricity have been developed by researchers at the Sandia National Laboratories in Albuquerque, N.M. The rate is the highest ever recorded for solar cells and is about 50% higher than the efficiency of commercial solar cells, which are 18% to 20% efficient.

The cells were produced by combining gallium arsenide cells produced by Varian Associates Inc. of Palo Alto, and crystalline silicon cells produced at Stanford University. The cells were stacked, with the Stanford cell on the bottom, to achieve the high efficiency. The peak rate was achieved using sunlight magnified to an intensity of nearly 500 times normal by optical devices.

The next step, the researchers said, will be to combine individual cells into a module suitable for use in practical applications.