Your solar powered mobile phone love a Sun Bath.

Mobile devices are becoming more and more intelligent - allowing users to watch movies on a mobile phone or laptop, or navigate with a PDA - but at the same time they require increasing amounts of power. To prevent the PC screen from suddenly going black, or the music from being interrupted, Fraunhofer researchers are working on micro power engineering solutions to provide the mobile power needed by modern communications devices.

Under the leadership of the Fraunhofer Institute for Solar Energy Systems ISE, scientists from various institutes are working on technologies that will make it possible to achieve greater power densities and, when combined with batteries in hybrid energy systems, extend operating times.

The concept of energy harvesting refers to using light, heat or motion to generate energy. For example, the Fraunhofer Institute for Physical Measurement Techniques IPM employs thermoelectrics: energy is generated by a heat flow source such as the user's wrist. Prominent clock makers use this technology to power watches. Micro-integrated thermo-electric converters can also be used to cool electronic components.

via redferret  / textually

Mitsubishi also did the same thing on their Music Porter phone

http://www.slashphone.com/111/2229.html