Waste light captured from a mobile could charge its battery

A team from Cambridge University hopes to capture energy from organic light-emitting diodes (OLEDs) inside a phone by using thin-film photovoltaic (PV) cells built into the screen.

Prof Arokia Nathan, project leader and fellow of the Institute of Electrical and Electronic Engineers (IEEE), told The Engineer that only 30–40 per cent of light generated by OLEDs is projected out of the front of the average mobile phone screen, with much of it being lost through the edges of the OLED.

Nathan and his collaborators at Canadian company IGNIS Innovation have created a proof-of-concept device that can harness this wasted light using PV cells around the edges of the display.

‘Once we have captured the light in the solar cell, that generates an output. It’s not very high but it’s something useful nevertheless,’ said Nathan.

The team, which was first based at the London Centre for Nanotechnology at University College London, believes that the captured photons could be used to help charge the phone and, because the technology can capture ambient light as well, it could one day lead to a phone that never has to be plugged in.