Dual function LEDs will make mobile devices more interactive

The pace of development in mobile technologies (particularly smart phones and tablet computers) has made these devices possibly the most disruptive to our way of life for decades. Research from the University of Illinois at Urbana-Champaign has now developed LEDs that could be used in mobile device displays that are capable of both emitting and detecting light, which would allow such functionality as charging from ambient light, changing display intensity according to light conditions, and detecting gestures to control the device without touching the screen.

The LEDs are composed of nanorods some 5nm in diameter, made from three types of semiconductor material. One type of semiconductor emits and absorbs visible light, while the other two control how electrons flow through the first material. The LEDs can switch between emitting and absorbing light faster than the human eye can see – three times faster than the normal refresh rate for standard LED. The display therefore appears to be on all the time even though it is performing other functions.