A charged view

摘要

With so much glass in buildings, cars and the screens of mobile devices, it is understandable why researchers would like to come up with transparent solar cells which could generate electricity and top up batteries. Solar cells work by absorbing the photons in sunlight and converting them into electrons, which are gathered by electrodes to flow into a circuit. Most solar cells are opaque to absorb all the light they can to maximise their efficiency. So, to look out of a window or use the screen of a smartphone, a layer of solar cells has to let some light through. Yet the more transparent the cells, the less energy they pro-duce-or at least that is how it works with traditional solar technology based on semiconducting materials such as silicon.