Key to manufacturing more efficient solar cells

Theorists long ago demonstrated that the maximum efficiency silicon solar cells might ever reach -- the percentage of energy in sunlight that might be converted to electricity we can use -- is roughly 33 percent. It takes hundreds of nanoseconds for energized electrons to move from the part of a solar cell that infuses them with the sun's energy, to the part of the cell that harvests the energy and converts it into electricity that can ultimately be fed into a power grid.