From left to right: Professor Karen Gleason, graduate students Miles Barr and Jill Rowehl, and Professor Vladimir Bulovic ́, working with others at MIT, have developed methods of depositing photovoltaic (PV) cells on sheets of ordinary paper and other inexpensive, lightweight, flexible materials. Inside the vacuum chambers shown behind them, they use a novel process to "vapor print" anodes that are integrally linked to the surface of the paper. In another lab, they use evaporative methods to deposit the remaining layers of the PV cells, producing solar arrays that can—even when folded—power small electronic devices. Photo: Stuart Darsch