A small hydrogen cell recharged by a miniature super efficient solar cell could soon replace the rechargeable batteries used in mobile phones. Developed by Fraunhofer Institute, in Germany, the technology is being adopted by many cell phone manufacturers who are busy building prototype devices using the new power cells. The phone will be able to run on solar power even under low lighting levels. Researchers have reduced the total number of process steps by 80 percent, making the solar cells commercially viable. They will soon demonstrate a high-performance solar module integrated in the lid of a Casio handheld telephone.