“In collaboration with Global Solar Energy of Tucson, Arizona, they have developed a cheap, practical and portable way to capture the sun’s rays by day and release them by night as useful light, wherever it is needed.The idea, called “portable light”, combines solar cells with light-emitting diodes attached to the surface of a fabric that can be made into bags, and thus carried around during daylight hours. In sunlight, the cells generate electricity that is stored in batteries stitched into the material. When it gets dark, the batteries power light-emitting diodes that are also sewn onto the cloth.
The solar cells themselves are made from a substance called copper indium gallium diselenide, Global Solar Energy’s speciality. This is not quite as good at capturing sunlight as silicon, the material from which solar cells are usually made, but it is less rigid and easier to work with. Crucially, a working cell can be made by spreading a thin layer of the stuff on another material, such as a sheet of plastic. The result is flexible and fairly robust”…. <More>