Summary:

Researchers published three papers today on an interesting semiconductor that can be used to create LEDs capable of producing any color.

Experimental setup of a 2D LED. Photo courtesy of MIT.
photo: MIT

Scientists have created super-thin LEDs that are strong, efficient and flexible enough to be easily integrated into clothing and super portable electronics. Three international research teams published papers in Nature Nanotechnology Monday describing the work.

“These are 10,000 times smaller than the thickness of a human hair, yet the light they emit can be seen by standard measurement equipment,” University of Washington materials science and engineering graduate student Jason Ross said in a release. “This is a huge leap of miniaturization of technology, and because it’s a semiconductor, you can do almost everything with it that is possible with existing, three-dimensional silicon technologies.”

The LEDs are made of tungsten diselenide, a semiconductor that belongs to a growing group of known two-dimensional materials that have impressive electrical properties. University of Washington researchers described isolating it by borrowing a graphene production technique called the Scotch tape method. It’s exactly what it sounds like: tape is applied to a hunk of material that contains tungsten diselenide and then repeatedly peeled away until a single 2D layer remains.

A 2D LED emits light. Photo courtesy of the University of Washington.

A 2D LED emits light. Photo courtesy of the University of Washington.

While graphene’s strength is to move electrons at super high speeds, tungsten diselenide’s skill is manipulating them in highly precise ways. MIT reported that it can be used to create LEDs that produce any color, which is very difficult to do with current LEDs.

Tungsten diselenide could also be applied to solar cells or displays for TVs and computers. Like LEDs, they could be integrated into clothes, windows and many other surfaces because of their thinness.

Getting to mass production is a challenge for any new 2D material. Tungsten diselenide will also have the challenge of overcoming the relative rareness of selenium, an element that makes up part of its chemical structure. But MIT postdoc Hugh Churchill noted in a release that it’s already known how to make it in large sheets. It also doesn’t need to be injected with atoms to be customized for different applications, unlike most semiconductors.

“The field of two dimensional materials is still at its infancy, and because of this, any potential devices with well-defined applications are highly desired,” Vanderbilt University assistant professor of physics and electrical engineering Kirill Bolotin told MIT. “Perhaps the most surprising aspect of this study is that all of these devices are efficient. … It is possible that devices of this kind can transform the way we think about applications where small optoelectronic elements are needed.”

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