We spend a fair bit of energy creating stray electromagnetic fields in order to make sure our cellular and WiFi devices are constantly fed with data. Every now and again, someone suggests that there must be a way to harvest these fields in order to charge our devices wirelessly. Now, a team of researchers (a Swiss-Chinese-Swedish collaboration) has suggested a simpler option: use the light that we’re constantly flooding our rooms with instead.

The researchers have developed a new version of a technology—dye-sensitized solar cells—that so far hasn’t lived up to its promises. They found that, in the dim light typical of the indoors, their solar cells outperformed the extremely efficient versions we normally reserve for trips to space.

So sensitive

In most solar cells, electrons are generated in a semiconductor and pulled out by wires. Useful current is generated by a second set of wires that sends electrons back in to the other side of the device. Efficiency is limited by the photovoltaic material itself, as well as the ability to pull electrons out of it before they simply hop back to where they originated.