“Quantum dot” technology may help light the future

via Oregon State University

via Oregon State University

Advances at Oregon State University in manufacturing technology for “quantum dots” may soon lead to a new generation of LED lighting that produces a more user-friendly white light, while using less toxic materials and low-cost manufacturing processes that take advantage of simple microwave heating.

The cost, environmental, and performance improvements could finally produce solid state lighting systems that consumers really like and help the nation cut its lighting bill almost in half, researchers say, compared to the cost of incandescent and fluorescent lighting.

The same technology may also be widely incorporated into improved lighting displays, computer screens, smart phones, televisions and other systems.

A key to the advances, which have been published in the Journal of Nanoparticle Research, is use of both a “continuous flow” chemical reactor, and microwave heating technology that’s conceptually similar to the ovens that are part of almost every modern kitchen.

The continuous flow system is fast, cheap, energy efficient and will cut manufacturing costs. And the microwave heating technology will address a problem that so far has held back wider use of these systems, which is precise control of heat needed during the process. The microwave approach will translate into development of nanoparticles that are exactly the right size, shape and composition.

“There are a variety of products and technologies that quantum dots can be applied to, but for mass consumer use, possibly the most important is improved LED lighting,” said Greg Herman, an associate professor and chemical engineer in the OSU College of Engineering.

“We may finally be able to produce low cost, energy efficient LED lighting with the soft quality of white light that people really want,” Herman said. “At the same time, this technology will use nontoxic materials and dramatically reduce the waste of the materials that are used, which translates to lower cost and environmental protection.”

Some of the best existing LED lighting now being produced at industrial levels, Herman said, uses cadmium, which is highly toxic. The system currently being tested and developed at OSU is based on copper indium diselenide, a much more benign material with high energy conversion efficiency.

Quantum dots are nanoparticles that can be used to emit light, and by precisely controlling the size of the particle, the color of the light can be controlled. They’ve been used for some time but can be expensive and lack optimal color control. The manufacturing techniques being developed at OSU, which should be able to scale up to large volumes for low-cost commercial applications, will provide new ways to offer the precision needed for better color control.

By comparison, some past systems to create these nanoparticles for uses in optics, electronics or even biomedicine have been slow, expensive, sometimes toxic and often wasteful.

Oher applications of these systems are also possible. Cell phones and portable electronic devices might use less power and last much longer on a charge. “Taggants,” or compounds with specific infrared or visible light emissions, could be used for precise and instant identification, including control of counterfeit bills or products.

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Smart light lets you control your environment

LiSense senses a user's movements by utilizing shadow maps on the floor to reconstruct their 3D posture (Credit: Dartmouth College)

LiSense senses a user’s movements by utilizing shadow maps on the floor to reconstruct their 3D posture (Credit: Dartmouth College)

What if the light in the room could sense you waving your hand as you enter? And what if it responded by introducing minute light changes that instructed your smart coffee machine to switch on?

Researchers at Dartmouth College have developed a sensing system called LiSense that aims to make the light around us “smart.” Not only does it use light to sense people’s movements, but it also allows them to control devices in their environment with simple gestures, using light to transmit information.

The goal is to use light to gesture and interact with objects in a room, just like how you’d use a Wii or Kinect to interact with a TV. Xia Zhou, lead author of a paper on the research, wants to use smart light to turn every indoor space into a cognitive space.

“Using purely visible light, we can not only stay connected to the internet, but also have the environment know and respond to what we do, how we behave, and how we feel,” Zhou tells Gizmag. “Smart light can bring intelligence to all the devices immersed in the light and allow them to act based on our behaviours.”

To get LiSense to track a person’s movements only through light, the researchers built a light-sensing testbed, with LED lights in the ceiling and light sensors on the floor. The system uses the shadows cast by a person standing on the testbed to reconstruct their 3D human skeletal posture in real time. LiSense, the team states, essentially works on the same principle as a shadow puppet, where a hand held before a light blocks certain light rays and not others.

“Consider a person standing under several lights,” Zhou explains. “If we can recover the shadow cast by each light in a different direction, we can aggregate the shadow information and collect the blockage information of a large number of light rays. We then use the information to search for a 3D skeleton posture that best matches the blockage information revealed by these shadows.”

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New LED Lights Are Stopping Insects Before They Bite Us And Give Us Diseases

Insects are attracted to light, but not to all types of light equally.

Insects are attracted to light, but not to all types of light equally.

Less blue light may mean fewer mosquitoes—and fewer infections.

Insects are attracted to light, but not to all types of light equally. It happens that when you put out different parts of the light spectrum, the little critters are less interested in invading your home and causing menace.

That is the conclusion of a new paper looking at the effect of new LED fixtures on insects. When researchers tuned lights away from traditional blue and ultraviolet wavelengths, insects were much less likely to come inside. The work is important because, of course, insects do a lot of damage: Millions of people still die from insect-borne diseases, like malaria and dengue. Potentially, distributing new types lightbulb could curb how these diseases spread.

“The research provides proof in concept that LED lamps can be customized to avoid specific areas of the spectrum that could have adverse environmental consequences, while still providing light for indoor use,” says lead author Travis Longcore, a professor at the University of Southern California. “For places in the world where glass windows and screens are uncommon, reducing insect attraction to indoor lights is a big deal.”

Longcore teamed up with André Barroso, a scientist with the Philips lighting group in Holland, which makes LED lights. They compared bulbs customizable to different wavelengths with standard LED bulbs (which still produce blue light), compact fluorescent (“energy efficient”) bulbs, and a control with no bulb at all. The special bulbs attracted 20% fewer insects than the others, despite emitting a more intense light.

Read more: New LED Lights Are Stopping Insects Before They Bite Us And Give Us Diseases


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Controlling genes with your thoughts

Thoughts control a near-infrared LED, which starts the production of a molecule in a reaction chamber. (Photo: Martin Fussenegger / ETH Zurich)

Thoughts control a near-infrared LED, which starts the production of a molecule in a reaction chamber. (Photo: Martin Fussenegger / ETH Zurich)

ETH researchers led by Professor Martin Fussenegger have developed the first gene network to be operated via brainwaves.

Depending on the user’s thoughts, it can produce various amounts of a desired molecule. The inspiration behind the project was a game that picks up brainwaves in order to guide a ball through an obstacle course.

It sounds like something from the scene in Star Wars where Master Yoda instructs the young Luke Skywalker to use the force to release his stricken X-Wing from the swamp: Marc Folcher and other researchers from the group led by Martin Fussenegger, Professor of Biotechnology and Bioengineering at the Department of Biosystems (D-BSSE) in Basel, have developed a novel gene regulation method that enables thought-specific brainwaves to control the conversion of genes into proteins – called gene expression in technical terms.

“For the first time, we have been able to tap into human brainwaves, transfer them wirelessly to a gene network and regulate the expression of a gene depending on the type of thought. Being able to control gene expression via the power of thought is a dream that we’ve been chasing for over a decade,” says Fussenegger.

A source of inspiration for the new thought-controlled gene regulation system was the game Mindflex, where the player wears a special headset with a sensor on the forehead that records brainwaves. The registered electroencephalogram (EEG) is then transferred into the playing environment. The EEG controls a fan that enables a small ball to be thought-guided through an obstacle course.

Wireless transmission to implant

The system, which the Basel-based bioengineers recently presented in the journal Nature Communications, also makes use of an EEG headset. The recorded brainwaves are analysed and wirelessly transmitted via Bluetooth to a controller, which in turn controls a field generator that generates an electromagnetic field; this supplies an implant with an induction current.

A light then literally goes on in the implant: an integrated LED lamp that emits light in the near-infrared range turns on and illuminates a culture chamber containing genetically modified cells. When the near-infrared light illuminates the cells, they start to produce the desired protein.

Read more . . . 


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Li-fi protocol allows use of the internet at the speed of light

Hands of business woman with a computer keyboard.

Sisoft Company in Mexico has developed a technology that can illuminate a large work space, an auditorium or an office, while providing full mobile internet to every device that comes into the range of the light spectrum.

The Mexican group managed to transmit audio, video and Internet across the spectrum of light emitted by LED lamps. This new technology, called Li-Fi or light fidelity, is presented as an alternative to Wi-Fi because it will maximize the original provided speed of the internet to offer safer data transfer and a transfer rate of up to 10 gigabytes per second.

The Li-Fi device circulates data via LEDs that emit an intermittent flicker at a speed imperceptible to the human eye. “As Wi-Fi uses cables to spread our connections, wireless transmission Li-Fi uses LED lamps that emit high brightness light”, said Arturo Campos Fentanes, CEO of Sisoft in Mexico.

Another advantage in comparison to Wi-Fi is that there is no way to hack the signal since the internet is transmitted by light, there is no way to “steal it”. Furthermore, it can be installed in hospitals areas that use radiation apparatus and generally block or distort internet signal, Campos Fentanes said.

With this new technology expansion through the market is seeked, with lower costs and a service increased by five thousand percent internet speed. Currently in Mexico the highest transfer rate is 200 megabytes per second. Just to get an idea, with Li-Fi you could quickly download an entire HD movie in just 45 seconds.

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