Electrical engineers of the University of Princeton are working on a cheap solar-powered charging system that can be printed on plastic and that transfers the produced electricity wirelessly. The solar cells are made from amorphous silicon (a-Si), a non-crystalline form of silicon. Crystalline silicon (c-Si) is much more efficient when it comes to converting sunlight into electricity but a-Si has the advantage that it can be processed at much lower temperatures (75 °C against 300 °C for c-Si), allowing it to be printed on plastic sheets.
The electric circuit is made out of the same material as the solar cells. And although a-Si has a lower electrical performance than c-Si, when it comes to producing cheap electricity-generating plastic sheet which can be put up anywhere, a-Si is best. By making the charging system available at a large scale, the Princeton engineers aim to have wireless electricity everywhere.