Lunar regolith, or rock structure, can be refined to produce enough silicon, aluminum and other useful metals to create solar cells, said Charles Horton, a researcher at the University of Houston's Texas Center for Superconductors and Advanced Materials. Raw soil could be turned into the base for such cells, he told a session at the NanoSpace 2002 conference.
"At about 1,500 degrees Centigrade, the regolith flows very smoothly," Horton said. "The surface is smooth enough to deposit a solar cell on, and (any nanometer-scale irregularities) might help scatter sunlight and generate more electrons."
Solar cells made on Earth use practically impurity-free silicon, but such quality would not be available initially from lunar silicon, Horton said. The team's nanoscale, or molecular-level, studies of a solar cell's makeup might overcome the quality gap, he said.
Solar cells use light energy to free up enough electrons for a practical current, but impurities block the electron flow, Horton explained. Studying solar cell films only a few hundred nanometers thick, the team discovered thinner films can counteract some impurities, although at a much lower efficiency than pristine films.
Lunar-soil cells should be able to generate about one volt apiece, Horton said. While that level is unusable on Earth, the Moon's wide-open surface and unfiltered sunshine mean much larger solar arrays could eventually generate about 150 kilowatts, enough electricity for a small, long-term settlement, he said.
Creating solar cells is itself a power-intensive process, but non-electrical methods, such as concentrating sunlight to melt lunar soil, could "boot-strap" whatever power source lunar explorers bring along, Horton said.
The conference, sponsored by the Institute for Advanced Multidisciplinary Research, the National Aeronautics and Space Administration and several universities, was set up to help NASA and the research community work out joint goals for nanotechnology.