MIT Researchers Improves Quantum Dot Creation Method

Wednesday, February 6, 2013

quantum dot technology

 Quantum Dots
MIT researchers have improved quantum-dot performance and creation with a new production method that could enable technological applications from more efficient computer displays to enhanced biomedical testing.
F ollowing on the heels of SONY and QD Vision, Inc.'s announcement recently that their new television technology uses quantum dots for the display, researchers at MIT have found a way to dramatically improve the creation and performance of the nanoscale fluorescent particles.

Quantum dots are tiny particles that emit light in a dazzling array of glowing colors. The particles have potential uses for many applications, but have faced a series of hurdles to improved performance.

Now an MIT team says that it has succeeded in overcoming all these obstacles at once, while earlier efforts have only been able to tackle them one or a few at a time.

The new process developed by the MIT team produces quantum dots with four important qualities: uniform sizes and shapes; bright emissions, producing close to 100 percent emission efficiency; a very narrow peak of emissions, with the colors emitted by the particles able to be precisely controlled; and an elimination of a tendency to blink on and off, which limited the usefulness of earlier quantum-dot applications.

The research study was published this week in the journal Nature Materials.

Quantum Dots

The new particles were made with a core of semiconductor material (cadmium selenide) and thin shells of a different semiconductor (cadmium sulfide). They demonstrated very high emission efficiency (97 percent) as well as small, uniform size and narrow emission peaks. Blinking was strongly suppressed, meaning the dots stay “on” 94 percent of the time.

A major factor in getting these particles to achieve all the desired characteristics was growing them in solution slowly, so their properties could be more precisely controlled, MIT chemistry postdoc Ou Chen explains. “A very important thing is synthesis speed,” he says, “to give enough time to allow every atom to go to the right place.”

The slow growth should make it easy to scale up to large production volumes, he says, because it makes it easier to use large containers without losing control over the ultimate sizes of the particles. Chen expects that the first useful applications of this technology could begin to appear within two years.


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