Nokia's finished its research project to see if it's worth jamming solar panels onto cellphones. A customized C1-02 (with a panel for a back cover) was tested in the Arctic circle, Sweden, Kenya and on the Baltic Sea. Due to the small size of the average device, however, the prototypes couldn't collect enough energy to properly recharge the battery in most scenarios. In conclusion? Unless you fancy buying a solar-phone the size of a barn door, it's probably not worth the effort -- at least for now.