Ran across this article today over at Engadget about a French startup called Wysips that has developed a transparent photovoltaic film, basically generating power from light, which could theoretically turn your smartphone’s touchscreen into a self-sufficient, solar charger. The film would be applied directly to the screen, below the capacitive layer, so no effect on touch performance. There are some issues with clarity but the developers are said to be working through it. May not generate enough power to keep a smartphone perpetually charged but it could easily extend the capacity of your battery without adding any weight or bulk.
The firm is in the process of locking up deals with suppliers, manufacturers and carriers, which sounds like a very good thing. The first commercial devices are expected to hit in 2012. Good stuff. You can read the whole article here.