Plastic solar cells roll into unlit villages

By day, the electronic devices that Frederik Krebs rolls off his printing presses could be mistaken for old plastic overhead-projector transparencies. Nightfall reveals their ingenious purpose: Snap the metal fasteners at the corners together and the sheets glow with reading-quality light. Krebs¿s sheets may prove to be much more than a curiosity, for the senior scientist at Denmark¿s Riso National Laboratory for Sustainable Energy has found a cheap way to integrate LEDs, photovoltaic (PV) cells, and ultrathin lithium batteries into a potentially life-saving lamp. He hopes to see them on sale next year, providing an affordable alternative to kerosene lighting for the more than 1.5 billion people in developing countries who lack access to electricity.