Phones of today, with their acre-sized touchscreens and constantly-syncing cloud services have pretty pitiful battery lives. So anything that can be done to preserve or extend this is a bonus in our books.

In a nutshell, this prototype OLED screen uses solar cells to absorb the scattered and wasted light, ducting it back into the screen.

According to Cambridge researcher Arman Ahnood, 36 per cent on average of the light generated by an OLED-type display projects straight out of the screen. The rest is lost to scatter and light bleeding from the edges of the screen.

So when you told your mates that your phone was bleeding edge, you meant it literally - albeit perhaps unknowingly.

Displaying some good old fashioned lateral thinking, the Cambridge University research team of which Ahnood is a member, installed photovoltaic cells on the back back and sides of OLED screens to capture this lost light.

Instead of routing the energy back into the battery though, the team worked with the energy group at Cambridge's Centre for Advanced Photonics and Electronics, adding a thin-film supercapacitor underneath the screen.

This system averaged an efficiency of 11 percent and peak efficiency of 18 percent, thereby resulting in less strain on the battery.

The amounts saved mean that phones could never be truly self sustaining using this, but being able to save a fraction of power, meaning we don’t have to charge as frequently, could make all the difference. The difference between getting that important email and not getting it. Or, more likely, the difference between finishing that Angry Birds level and not finishing it...

Source: IEEE Spectrum, via Extreme Tech, Engadget