...uses magnifying lenses to greatly concentrate the amount of solar energy reaching a cell. The technique allows a centimetre-square photovoltaic cell to capture 230 watts of energy and generate 70 watts of "usable" electricity. According to...
http://www.itpro.co.uk/news/198243/ibm-makes-solar-energy-childs-play.html
...newspaper, is designed to connect to mobile phones and laptops. Researchers in Japan have produced a 16-centimetre-square prototype just one millimetre thick which weighs five grams. It incorporates 144 plastic "paddles" beneath a...
http://www.accessible-devices.com/portable.html