Nanorods LED can make multifunctionals displays

Due to a new nanorods LED technology, soon cellphones and other devices could be controlled by touchless gestures and getting charged by ambient light.

The LED is made of very small nanorods on a thin film, they might enable new features like multitasking and new interactive functions. It was created by researchers at the University of Illinois.

“These LEDs are the beginning of enabling displays to do something completely different, moving well beyond just displaying information to be much more interactive devices,” said professor Moonsub Shim, author of the study. “That can become the basis for new and interesting designs for a lot of electronics.”

The infinitesimal nanorods are just 5 nanometers in size and consists of three different types. The first emits and absorbs light while the other two act as semiconductors controlling the flow through the material. This makes the LED to emit,sense and respond to the light.

These nanorods can switch so fast from emiting to detecting and back that the display appears continuously. They are also continuously emiting and detecting and they can be programmed to respond in many different ways.


“You can imagine sitting outside with your tablet, reading. Your tablet will detect the brightness and adjust it for individual pixels,” Shim said. “Where there’s a shadow falling across the screen it will be dimmer, and where it’s in the sun it will be brighter, so you can maintain steady contrast.”

The scientists showed that the pixels can adjust brightness, as well as pixels that respond to a approaching finger, which allows for interactive displays that can be used with touchless gestures.

The researchers also showed the LED responded to a laser stylus, which can allow writing  or drawing on whiteboards with just light emitted from them. It can also convert the light to electricity.

“The way it responds to light is like a solar cell. So not only can we enhance interaction between users and devices or displays, now we can actually use the displays to harvest light,” the author said. “So imagine your cellphone just sitting there collecting the ambient light and charging. That’s a possibility without having to integrate separate solar cells. We still have a lot of development to do before a display can be completely self-powered, but we think that we can boost the power-harvesting properties without compromising LED performance, so that a significant amount of the display’s power is coming from the array itself.”

The nanorod displays can also interact with each other like communication arrays. It will certainly be slower that current device-to- device tech like Bluetooth, but they are serial which means that they can send only one bit at a time. Two such LED displays can communicate with each other with as many  bits of pixels are on the screens.

“We primarily interface with our electronic devices through their displays, and a display’s appeal resides in the user’s experience of viewing and manipulating information,” said  co-author Peter Trefonas, . “The bidirectional capability of these new LED materials could enable devices to respond intelligently to external stimuli in new ways. The potential for touchless gesture control alone is intriguing, and we’re only scratching the surface of what could be possible.”

The professors did their demonstrations with only red LEDs, and they are now creating ones with blue, green and red pixels, along with improving the light-reaping nanorods by changing their composition.

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