University of Washington Unveils 3-Atom-Thick LED

March 12, 2014 By Leon Walker

UWUniversity of Washington scientists have built the thinnest-known LED that can be used as a source of light energy in electronics.

The LED, which is only three atoms thick yet mechanically strong, is based off of two-dimensional, flexible semiconductors, making it possible to stack or use in much smaller and more diverse applications than current technology allows. The graphical representation shows the layers of the 2-D LED and how it emits light.

Most consumer electronics use three-dimensional LEDs, but these are 10 to 20 times thicker than the LEDs being developed by the UW.

The UW LED is 10,000 times smaller than the thickness of a human hair, yet the light it emits can be seen by standard measurement equipment, according to UW. University researchers described the technology as a huge leap forward in the miniaturization of technology. Because it’s a semiconductor, you can do almost everything with it that is possible with existing, three-dimensional silicon technologies, researchers said.

The UW’s LED is made from flat sheets of the molecular semiconductor known as tungsten diselenide, a member of a group of two-dimensional materials that have been recently identified as the thinnest-known semiconductors. Researchers use regular adhesive tape to extract a single sheet of this material from thick, layered pieces in a method inspired by the 2010 Nobel Prize in Physics awarded to the University of Manchester for isolating one-atom-thick flakes of carbon, called graphene, from a piece of graphite.

The research team is working on more efficient ways to create these thin LEDs and looking at what happens when two-dimensional materials are stacked in different ways. Additionally, these materials have been shown to react with polarized light in new ways that no other materials can, and researchers also will continue to pursue those applications.

In August, a Michigan scientist and his team announced they had developed an inexpensive three-dimensional graphene honeycomb that they say can replace the very expensive platinum used in solar cells. Dye-sensitized solar cells are thin and flexible and easy to make, says Michigan Tech News, but a critical component that goes into making them is platinum. The cells require very little platinum, but even for miniscule amounts, the metal is prohibitively expensive at $1,500 per ounce. Michigan Technological University’s Yun Hang Hu, a material science and engineering professor, and his team have developed a 3D version of graphene that is shaped like a honeycomb.

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