Image via Michael Geminder

Scientists have developed energy efficient, ultra-thin light-emitting diodes (LEDs) for next-generation communication technologies.

Light sources that reliably convert electrical to optical signals are of fundamental importance to information processing technologies. Energy-efficient and high-speed LEDs that can be integrated onto a microchip and transmit information are one of the key elements in enabling high volume data communication.

Two-dimensional (2D) semiconductors, graphene-like, atomically thin materials, have recently attracted significant interest due to their size (just a few atoms thick), well-defined light emission properties, and their prospects for on-chip integration. While, in recent years, researchers have succeeded in fabricating LEDs based on these materials, realizing efficient light emission has remained a challenge.

An efficient LED device converts most of its electrical power input into light emission (i.e., with minimal losses due to conversion into other forms of energy such as heat). Previous studies on LEDs based on 2D semiconductors reported that a large amount of electrical current is needed to trigger light emission. This means that a substantial fraction of the input electrical power is dissipated as heat instead of generating light.

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Chemical engineers have generated ultra-pure green light for the first time.

The new light-emitting diode paves the way for visibly improved color quality in a new generation of ultra-high definition displays for TVs and smartphones.

Electronic devices must first be able to produce ultra-pure red, blue, and green light in order to enable the next generation of displays to show images that are clearer, sharper, richer in detail, and with a more refined range of colors. For the most part, this is already possible for red and blue light; green light, however, has been at the limits of technology.

This is due mainly to human perception, since the eye is able to distinguish between more intermediary green hues than red or blue ones. “This makes the technical production of ultra-pure green very complex, which creates challenges for us when it comes to developing technology and materials,” says Sudhir Kumar of ETH Zurich, co-lead author of the study.

Ultra-pure green plays a key role in extending the color range, or gamut. Ultimately, new hues arise from the technical mixture of three base colors: red, blue, and green. The purer the base colors, the broader the range of hues a screen can display. The new LED is in line with 97 to 99 percent of the international standard for Ultra HD, Rec.2020. By comparison, the purest color TV displays currently available on the market cover on average only 73.11 to 77.72 percent; none exceeds 80 percent.

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Image: CC0 Public Domain

Tired of slow internet connections and download speeds? Well, you may be in luck. According to an article from Popular Science, some researchers are looking toward LED technology to replace Wi-Fi.

Wi-Fi is essentially a series of waves traveling along a narrow, electromagnetic spectrum. The more users, the more crowded and congested the spectrum gets, and the more crowded, the slower connection speeds become. The problem, however, is that researchers cannot create more spectrum to allow the waves to pass faster.

Because of this, some are looking to another solution: LEDs.

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Smartphones are amazing little bundles of electrochemistry. From the sensors that pick up your touch and analyze your voice to the battery that is small and powerful enough to provide enough power to run applications on demand – the innovative science behind smartphones has changed the lives of people around the world.

But sometimes those changes are not completely positive. With increased dependence on smartphones, many people now roam the sidewalk with their nose buried in their phones. According to The Wall Street Journal, the number of distracted pedestrians using cellphones is up 124 percent from 2010. Some researchers are even blaming portable electronic gadgets for 10 percent of pedestrian injuries and a half-dozen deaths each year.

In Germany, these distracted pedestrians have been deemed “sombies,” or “smartphone zombies.” And the German government isn’t just looking to throw out a new buzzword, they’re also seeking to solve this issue.

According to reports from The Local, the city of Augsburg recently installed rows of LED lights into the sidewalk that can sense when distracted pedestrians are approaching and give off a bright flash of red to warn them to not mindlessly wander into the street.

“We realized that the normal traffic light isn’t in the line of sight of many pedestrians these days,” said Tobias Harms of the Augsburg city administration in an interview with The Augsburger Allgemeine. “So we decided to have an additional set of lights – the more we have, the more people are likely to notice them.”

Using this National Geographic image, Dr. Chanda is able to demonstrate the color-changing abilities of the nanostructured reflective display.
Image: University of Central Florida

The development to the first colorful, flexible, skin-like display is taking wearable electronics to a whole new level.

Researchers from the University of Central Florida’s NanoScience Technology Centre have created a digital “skin” that can cloak wearers in realistic images. This new technology could be applied to concepts as simple as outfit changes, or more serious matters like replacing camouflage for members of the military.

The research was led by Professor Debashis Chanda, who took inspiration for this development from nature.

“All manmade displays – LCD, LED, CRT – are rigid, brittle and bulky. But you look at an octopus, they can create color on the skin itself covering a complex body contour, and it’s stretchable and flexible,” Chanda said. “That was the motivation: Can we take some inspiration from biology and create a skin-like display?”

This from Wired:

The result is described as an ultra-thin nanostructure, which can change color when different voltage is applied. The method uses ambient light rather than its own light source, meaning no bulky backlighting is needed, and the structure is relatively simple; a thin liquid crystal layer above and metallic “egg carton” like nanomaterial that reflects wavelengths selectively.

Read the full article here.

In the end, the researchers developed something that is 25 times thinner than human hair for easy application to fabrics and plastics.

Head over to the Digital Library to read about some of the latest research and innovations in nanomaterials.

When it comes to light bulbs, we’ve seen a lot of transformation since Thomas Edison’s practical incandescent bulb. Since then we’ve delved into fluorescent lights, and more recently, LEDs. Now we’re moving on to the next big thing in light bulbs, and that just may be graphene.

The new bulb is projected to last longer and cut energy use by 10 percent.

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The headset, worn mounted on carrier frames just above or in front of the eyes, houses a high-definition camera, OLED screens, and multiple supporting technologies used to capture and display a real-time video-feed.

Visual impairments and blindness affect millions of people globally. According to the World Health Organization, 39 million people are blind and 246 million have low visions, globally. Now, a company by the name of eSight is stepping into the game to assist in restoring eyesight to the legally blind through a new feat of engineering.

According to the company, the glasses can adapt to any situation and maintain peripheral sight. While the company knew their goal, the engineering challenge was to electronically optimize the minimal useable vision that exists in people with low vision so they can more fully participate in everyday life.

This from Tech Times:

The devices use a prescription lens frame, holding a headset. A hand controller is used to adapt a live video stream, optimizing an LED display, placed directly in front of the eyes of a user. These controls permit the operator to adjust contrast, brightness, and color of the image, in order to provide better vision.

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Researchers from the University of Sydney have recently published their findings that quantum dots made of graphene can improve bio-imaging and LEDs.

The study was published in the journal Nanoscale, where the scientists detailed how activating graphene quantum dots produced a dot that would shine nearly five times bright than the conventional equivalent.

Essentially, the dots are nano-sized semiconductors, which are fluorescent due to their surface properties. However, this study introduces the utilization of graphene in the quantum dot, which produces an extra-bright dot that has the potential to help medicine.

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More and more households are using LED light bulbs due to improved efficiency, reliability, and now a more affordable cost over their incandescent cousins. With droves of scientists researching in the area of LED and producing new developments, these bulbs are beginning to become the new norm.

Let’s take a look at the journey the LED bulb has gone though thus far.

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Thermal management represents about 25-30 percent of total costs in a LED bulb, second only to the LEDs themselves.
Credit: Cree

LED maker Cree has introduced a new consumer bulb that costs less, lasts longer, and consumes less energy than the traditional bulb.

The company’s new bulb does not use the heats sinks that LED bulbs typically use. An LED bulb’s metal collar or other heat sink serves to draw away heat from the bulb to ensure a long life. Accordingly, this makes the bulb more expensive and give it a bulky look.

By eliminating the heat sink, Cree lowered the bulb cost from $9.97 for a “soft white” 40-watt to $7.97.

This from IEE Spectrum:

In its new design, heat is removed from the LEDs through convection, or a flow of air through the bulb. The LEDs are mounted on circuit boards, rather than the metal tower. As the diodes heat up, they draw air from outside the bulb through small vent-like openings at the base and on the top. Because hot air rises, air flows continually through the bulb to cool the LEDs. The airflow circulates whether the bulb is vertical, horizontal or upside down, Watson says.

Read the full article here.

The new generation bulb will last 25,000 hours and consume 85 percent less energy than an incandescent bulb.

Want to know what the future has in store for LEDs? Check out what our scientists have been researching to propel this technology. While you’re over there, sign up for our e-Alerts so you are up-to-date on what is happening in the world  of electrochemical and solid state science and technology.