In Xiaolin Zheng's version of the future, installing solar panels could be as simple as applying a sticker. In China, the rooftops of many buildings are packed with solar energy devices," says Zheng. "One day my father mentioned how great it would be if a building's entire surface could be used for solar power, not just the roof, but also walls and windows." An invention from Zheng's research team at Stanford University might someday make that possible. They have created a type of solar cell that is thin, flexible, and adhesive-a solar sticker. "Our new technique lets us treat the solar cells like a pizza," explains Zheng. "When you bake pizza, you use a metal pan that can tolerate high temperatures. But when it's time to distribute the pizza economically, it's placed in a paper box." Working with her students, Zheng set out to fabricate solar cells on a silicone or glass surface as usual, but she inserted a metallic layer between the cell and the surface. After some trial and error, the team was finally able to peel away the metallic layer from the surface. The result was ... skinny, bendable cells [that] can produce the same amount of electricity as rigid ones. According to Zheng. "The silicon wafers come through the process clean and shiny. So just like a pizza pan, they can be used again and again, which translates to savings." And because the solar stickers are lighter than conventional panels, they will be easier and less expensive to install.