Tiny quantum dots hold promise for future source of lighting

Jan 12, 2012

(PhysOrg.com) -- UT Dallas researchers are making strides in understanding the workings of quantum dots – nanosized particles that have immense potential in several industry applications.

Quantum dots could be used in a variety of ways ranging from illuminating the human body in high-tech medical imaging to increasing the efficiency of energy sources.

These tiny, semiconducting have a dark side though—they blink unpredictably. The effect is similar to switching a on and off, substantially diminishing the effectiveness of light emission.

“Quantum dots are regarded as the next generation of efficient light sources because of their efficiency in both emitting and absorbing light,” said Dr. Anton Malko, assistant professor at UT Dallas. “Keeping them from blinking is key to facilitating their widespread use.”

The findings are detailed in a recent issue of the journal Nano Letters.

Malko and fellow researchers from Los Alamos National Laboratory reported that by increasing the size of the exterior shell of the particles, blinking could be suppressed.

Researchers altered these quantum particles, which are mere billionths of a meter in size, by increasing them from around 4 nanometers to 15 nanometers.

“We observed that the same process that causes the dots to blink didn’t have the same effect when we scaled up the size,” Malko said. “We found that this process, the so-called “Auger” recombination, is strongly dependent on the thickness of the quantum dot’s shell and allows complete blinking suppression for large shell particles.

“Gaining a better understanding of all of the forces at work in this phenomenon will lead, hopefully, to a way of reducing these unpredictable behaviors in quantum dots,” Malko said.  Making with uninterrupted light output will certainly help in their employment in a variety of applications ranging from biomedical imaging to quantum information processing.

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thuber
not rated yet Jan 12, 2012
QDots also have application to civilian lighting, but the materials still have the problem that they degrade over time due to friction with the electrons resulting in diminished light. Once this problem is solved, QDot lighting panels will hit the consumer markets as a dramatically cheaper, much more efficient alternative to lightbulbs.