Stacked solar cells—which are exactly what they sound like—are some of the most efficient solar-sucking power generators on the market today. In general, they can turn just less than half of the sunlight they absorb into pure power. But stacked cell is only as strong as its weakest part; you have to connect the stacked cells in such a way that the energy doesn't get wasted in the connections. That gets especially hard under a lot of light.
Scientists at North Carolina State University recently discovered that a thin film of gallium arsenide in the solar cell junctions can stop virtually all voltage loss, and let the cells work efficiently under the power of 70,000 suns. Yeah, we only have one sun, but thanks to lenses we can beef that up to at least a few thousand in concentrated power.
Dr. Salah Bedair, a senior author of the study, described the accomplishment to PhysOrgthis way:[It] is more than sufficient for practical purposes, since concentrating lenses are unlikely to create more than 4,000 or 5,000 suns worth of energy. ...This should reduce overall costs for the energy industry because, rather than creating large, expensive solar cells, you can use much smaller cells that produce just as much electricity by absorbing intensified solar energy from concentrating lenses. More here.