Gizmorama - November 23, 2015

Good Morning,

Most people think lasers are cool. Well, now they literally are cool. Researchers have created the technology to create laser that emits a refrigeration effect. That's right, Mr. Freeze, it's a freeze ray of sorts. That's really cool!

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,
Erin

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*-- Scientists build cheaper, better LED --*
TALLAHASSEE, Fla. - Florida State researchers have developed a cheaper, more efficient LED, or light-emitting diode, the technology that illuminates the modern, energy-efficient home and delivers the picture on most flat screen TVs.

The key to the light's cheaper, brighter glow is a newly developed class of materials called organometal halide perovskites.

"Early work suggested perovskites could be a promising material to build LEDs," physicist Hanwei Gao said in a press release. "But, the performance was not up to their potential. We believed there was significant room for improvement."

Gao and his colleague, chemical engineer Biwu Ma, spent months using synthetic chemistry to fine-tune the materials in the lab, tweaking the molecular architecture.

An diode is a material that has been atomically manipulated to allow electricity to only flow in one direction, like a one-way street current. When two one-way streets are forced onto each other, the electric energy escapes in the form of photons.

The power, color and efficiency of a diode's light-emitting properties is largely determined by the material its made with.

Gao and Ma designed a perovskite material capable of emitting 10,000 candelas per square meter when powered by 12 volts. The diodes in most computer screens put out just 400 candelas per square meter.

"Such exceptional brightness is, to a large extent, owing to the inherent high luminescent efficiency of this surface-treated, highly crystalline nanomaterial," Gao explained.

The organic-inorganic hybrid material is easily and quickly made, which the researchers hope will translate to cheap, scalable production. LEDs are much more efficient than other lighting sources, but adoption in the home has been slow-going due to their relative expense.

"If you can get a low cost, high performing LED, everyone will go for it," Ma said. "For industry, our approach has a big advantage in that earth abundant materials can be processed in an economic way to make the products."

The new diode material was recently described in the journal Advanced Materials.


*-- Scientists create refrigeration effect with a laser, a first --*
SEATTLE - Whether they're mounted on sharks or emanating from the Death Star, lasers can deliver destructive levels of heat. But scientists at the University of Washington have managed to cool water using a laser, the first time researchers have used the technology to create a refrigeration effect.

Researchers created the laser beam by fixing an infrared laser light on a microscopic crystal suspended in liquid by a laser-powered tractor beam. The glow emanated by the laser-saturated crystal contained only slightly more energy than the amount of light absorbed by the crystal, extracting energy from the crystal and water.

The crystal was designed to change color as it cooled, allowing scientists to monitor whether or not their experiment was working in real time.

"The real challenge of the project was building an instrument and devising a method capable of determining the temperature of these nanocrystals using signatures of the same light that was used to trap them," researcher Paden Roder explained in a press release.

Roder is the lead author of a new paper on the discovery, published this week in the journal PNAS.

Currently, the process is rather energy intensive. But Roder and his colleagues hope to improve the technology so that it is scalable.

"Few people have thought about how they could use this technology to solve problems because using lasers to refrigerate liquids hasn't been possible before," Roder said. "We are interested in the ideas other scientists or businesses might have for how this might impact their basic research or bottom line."

One possibility would be to use the laser technology to slow down or silence biological processes. Slowing down the areas of the cell responsible for division and replication could allow scientists time to see and study these little-understand processes in real time.

Similarly, a single neuron could be frozen into silence using the laser's temperature-dropping glow. Researchers could then study how surrounding neurons and neural pathways adapt to its momentary absence.

"There's a lot of interest in how cells divide and how molecules and enzymes function, and it's never been possible before to refrigerate them to study their properties," said senior study author Peter Pauzauskie, an assistant professor of materials science and engineering at Washington.

"Using laser cooling, it may be possible to prepare slow-motion movies of life in action," Pauzauskie added. "And the advantage is that you don't have to cool the entire cell, which could kill it or change its behavior."

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