How does a solar cell work?

How does solar conversion work now and how do we want it to work in the future? Paul Altivisatos, interim director for Lawrence Berkeley National Laboratory at UC Berkeley, explains how a solar cell works and how the solar energy of the future, via a solar fuel generator that converts energy the same way plants do, can become more efficient. He says that rather than looking for what's next, he looks to the end result--an ideal usage for materials.