Researchers at Northwestern University have found one way to stop a leak: get rid of the liquid. A new variation on the Grätzel solar cell replaces a short-lived organic dye with a solid alternative. The molecular dye the solid substance replaces was corrosive, at risk of leaking and only lasted about 18-months -- by replacing it, researchers plan to pave the way for a more affordable (and less toxic) alternative. Northwestern's new design flaunts a 10.2-percent conversion efficiency, the highest ever recorded i