Duke’s New All-Seeing Sensor Catches the Entire Rainbow in a Super-Fast Flash

The Flash of the Tech World: A Sensor That Blinks Faster Than a Superhero

A futuristic glimpse into the ultra-fast world of multispectral sensing.

Imagine you are trying to win a staring contest against a beam of light. Spoiler alert: you’re going to lose. But while most of us are stuck in the slow lane of biology, scientists at Duke University have been busy building a speed demon that would make even the fastest superhero jealous. They have cooked up a brand-new, ultrathin photodetector that doesn’t just see the world—it captures it at a pace that is frankly hard to wrap our human brains around. This little gadget is the fastest "pyroelectric" detector ever created, and it’s about to change how we see everything from our doctor’s office to the furthest reaches of the galaxy.

To understand how cool this is, we first have to talk about speed. Most of us think a "blink of an eye" is fast. In the world of high-tech sensors, a blink is basically an eternity. This new detector can generate a signal in just 125 picoseconds. How fast is a picosecond? Well, if you were to divide one second into a trillion pieces, a picosecond is just one of those tiny slices. It’s so fast that in the time it takes for this sensor to react, a beam of light has only traveled about an inch. It’s the Usain Bolt of the electronics world, but without the cool yellow jersey.

But wait, there’s more! Not only is it incredibly fast, but it’s also a master of disguise. Most sensors are picky eaters; they only want to "see" certain types of light, like visible light or infrared. This new Duke invention is more like a "see-it-all" buffet. It can sense light across the entire electromagnetic spectrum. We’re talking about everything from the heat radiating off your morning coffee to the ultraviolet rays that give you a sunburn. Because it is so versatile, it’s being called a multispectral powerhouse. It’s like having X-ray vision, heat-vision, and regular vision all packed into a tiny, ultrathin chip.

So, how did they do it? The secret sauce lies in something called a "pyroelectric" material. These materials are like magic sponges that turn heat from light into electricity. Usually, these materials are a bit slow and clunky, but the team at Duke figured out how to make them into a sort of "nano-sandwich." They used tiny cubes of gold to trap the light, squeezing it into a super-thin layer of material. This creates a massive amount of heat in a tiny space very, very quickly. Because the setup is so small—literally thinner than a fraction of a human hair—the heat doesn't have far to travel, allowing the sensor to reset and fire again in the blink of a... well, in 125 picoseconds.

Now, you might be wondering: "That’s great for the scientists, but what does it do for me?" The answer is: plenty! Let's start with the doctor’s office. Imagine a camera that can look at your skin and instantly tell the difference between a healthy mole and something more concerning by looking at light frequencies the human eye can't even dream of. Or, think about a surgeon who can see the exact edge of a tumor in real-time during an operation because their camera is so fast and sensitive it can distinguish between different types of tissue based on how they reflect heat. It’s like giving doctors a pair of super-powered goggles.

The fun doesn’t stop at medicine. Let’s talk about snacks! This technology could be a game-changer for agriculture. Farmers could use drones equipped with these "super-sensors" to fly over massive fields of corn or wheat. The cameras would be able to see exactly which plants are thirsty, which ones are getting sick, and which ones are perfectly happy, all by analyzing the subtle light signatures they give off. It’s like the plants are sending a text message directly to the farmer saying, "Hey, bring me some water over here!" This means more food for the world and less wasted water and fertilizer.

And for those who like to look up at the stars, the sky isn't even the limit. Space-based sensing is a huge deal. When we send satellites into orbit, they are usually weighed down by heavy, specialized cameras that can only see one thing. This ultrathin, lightweight sensor could replace those bulky tools. It could help us find water on distant planets, track weather patterns on Earth with pinpoint accuracy, or even spot asteroids that are trying to sneak up on us. Because it’s so thin and light, it saves room on the rocket for other important stuff—like extra fuel or more science experiments.

In the end, what the team at Duke University has created is more than just a piece of hardware; it’s a new way of interacting with the invisible world. We are surrounded by light that we can’t see and data that we can’t capture because our current technology is too slow or too limited. By breaking the speed record and opening up the entire spectrum, these researchers are handing us the keys to a whole new dimension of discovery. Whether it's saving lives in a hospital, saving crops on a farm, or exploring the cosmos, the future looks incredibly bright—and it’s arriving faster than ever before!

The future isn't just coming; it's already here, and it's traveling at 125 picoseconds per second!

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Zap! Laser beams flip the script on magnets for super smart circuits

The Ultimate Magnetic Makeover: Scientists Teach Magnets to Dance!

Imagine for a second that you have a tiny, stubborn compass. No matter how much you shake it or plead with it, that needle is determined to point North. It’s stuck in its ways, a total traditionalist. Now, imagine you could pull out a tiny laser pointer, give it a quick "zap," and suddenly the compass decides that South is the new North. It’s a total personality flip, a magnetic identity crisis, and it's all happening thanks to some incredibly clever "tech-wizards" in Switzerland.

In the world of physics, magnets have always been the reliable, slightly boring workhorses of our gadgets. They sit inside your hard drives, they hold your takeout menus to the fridge, and they generally stay exactly as they are. But the brilliant minds over at the University of Basel and ETH Zurich decided that magnets needed a bit more "pizzazz." They didn’t want magnets that just sat there; they wanted magnets that could change their minds at the speed of light. And guess what? They actually pulled it off!

So, how does this magic trick work? Usually, if you want to flip the polarity of a ferromagnet (that’s the fancy name for the strong magnets we know and love), you need to hit it with another magnetic field. It’s a bit like using a hammer to push a nail—it’s effective, but it’s a bit clunky and uses a fair amount of energy. It’s very "industrial revolution." The Swiss team decided to skip the hammer and go straight for the precision of a "light-saber."

By using a specific type of laser beam, they were able to tickle the atoms inside a special ferromagnet just the right way. Think of it like a choreographer directing a massive dance troupe. With one flash of light, all the tiny magnetic moments inside the material—which were all pointing one way—suddenly did a synchronized 180-degree turn. It’s the world’s fastest, smallest, and coolest U-turn. This isn't just a fun party trick; it’s a breakthrough that could rewrite the rulebook for how we build electronics.

Why should we care about magnets doing gymnastics? Well, think about the devices you use every day. Your smartphone, your laptop, and even your smartwatch are full of fixed circuits. Once they are built, their "brains" are pretty much set in stone. If we want them to do something different, we usually have to rely on complex software to work around the rigid hardware. But what if the hardware itself could shape-shift? That is where the real magic happens.

With this new laser-flipping technique, we are looking at a future where electronic circuits are as adaptable as a piece of clay. Because light can be used to switch magnetic states so quickly and precisely, we could create "reconfigurable" electronics. Imagine a computer chip that physically changes its internal pathways depending on whether you are playing a high-intensity video game or trying to calculate the trajectory of a rocket to Mars. It’s like having a house where the walls move to create a kitchen when you're hungry and a bedroom when you're tired.

This "light-driven" approach is also a massive win for the environment and your battery life. Traditional ways of switching magnetic states often generate a lot of heat. If you’ve ever felt your laptop getting hot enough to fry an egg on your lap, you know exactly what I mean. Using lasers is incredibly efficient. It’s a "cold" process, meaning we can flip those magnetic poles without wasting heaps of energy as heat. This could lead to gadgets that stay cool to the touch and batteries that last for days instead of hours. Who wouldn't want a phone that doesn't turn into a pocket-heater after ten minutes of scrolling?

But wait, there’s more! This technology also opens the door to ultra-fast data storage. Currently, we store information by flipping magnetic bits, but doing it with electricity has its speed limits. Light, on the other hand, is the fastest thing in the universe. By using lasers to write data into magnetic materials, we could potentially see storage speeds that make our current "high-speed" SSDs look like they are running through molasses. We are talking about moving entire libraries of information in the blink of an eye.

The researchers are currently working with a "special" kind of ferromagnet, so don't expect your fridge magnets to start responding to your laser pointer just yet. There is still a lot of fine-tuning to be done. They need to make sure the process is stable, repeatable, and ready for the big leagues of mass production. However, the "proof of concept" is a massive leap forward. It proves that light and magnetism are much better friends than we previously thought.

In conclusion, the next time you see a laser pointer, don't just think about annoying your cat. Think about the fact that researchers are using those same principles to create a new generation of smart, adaptable, and lightning-fast technology. We are moving away from the era of "static" machines and into an era where our gadgets can think, move, and change their very nature with just a flash of light. The future is looking very bright—literally!

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Twist and Shout to Create Giant Magnetic Swirls at the Perfect Angle

The Great Atomic Twist: How Tiny Magnets Learned to Do the Moiré Tango

An artist's impression of giant magnetic swirls dancing across atomic layers.

Imagine, if you will, the world’s thinnest sandwich. We aren't talking about a deli sub or even a fancy tea sandwich. We are talking about layers of material so thin that if you tried to pick one up, you’d be grabbing a single layer of atoms. Specifically, we’re looking at Chromium Triiodide, a material that physicists treat like a magnetic superstar. Normally, these layers sit quietly, doing their magnetic chores, but scientists recently decided to give them a bit of a spin—literally. By stacking two of these atomic sheets and twisting them relative to one another, they’ve unlocked a secret disco of magnetic patterns that no one saw coming.

This "twist" creates something called a moiré pattern. You’ve probably seen this effect in real life without knowing its fancy name. Have you ever looked through two screen doors overlapping and seen those weird, shifting wavy lines? That’s moiré! At the atomic level, when you twist two crystalline grids, you create a brand-new "super-grid" that is much larger than the original atoms. It’s like taking two fine-mesh sieves and rotating them until a giant, beautiful kaleidoscope pattern emerges. In the world of physics, this usually means the electrons have a new playground to run around in, changing how the material conducts electricity or holds onto data.

But here’s where the story gets weird and wonderful. In most materials, the magnetic patterns are expected to stay inside the lines of that moiré grid. It’s like a coloring book where the magnets are the crayons, and they usually stay within the borders of the squares. However, in Chromium Triiodide, the magnets decided they didn't care much for the rules. Instead of tiny, predictable patterns, the researchers spotted giant magnetic "tornadoes" called skyrmions. These aren't your average, run-of-the-mill skyrmions; they are absolute behemoths, stretching across hundreds of nanometers. To an atom, that’s like a human seeing a storm the size of a continent!

The real "aha!" moment came when the scientists realized that bigger isn't always better, but there is definitely a "Goldilocks" zone for twisting. You might assume that the more you twist the layers, the bigger or smaller the patterns would get in a straight line. Nope! The universe loves a good plot twist. The size of these magnetic giants actually peaks at a very specific angle. It’s like tuning a radio: if you turn the knob too far left or too far right, you get static. But when you hit that magical sweet spot, the signal—or in this case, the giant magnetic texture—comes through loud and clear. This "angle-controlled magnetism" is a total game-changer for how we think about designing materials from the ground up.

Why should we care about giant magnetic swirls on a tiny piece of atomic paper? Because these skyrmions are "topological." That’s a fancy way of saying they are incredibly stable. Think of them like a knot in a string; you can’t just shake the string and expect the knot to disappear. You have to physically untie it. In the world of computers and gadgets, stability is the holy grail. If we can use these magnetic knots to store information, we could create devices that don't lose their memory if they get bumped or lose power. Even better, moving these textures around takes very little energy, which means your future smartphone might stay charged for weeks instead of hours.

We are entering an era of "geometric electronics," where we don't necessarily need to change the chemistry of a material to make it do something new. We just have to be really good at origami. By folding, stacking, and twisting these atomic sheets, we are essentially building tiny machines out of pure geometry. It’s like playing with the world’s most advanced set of Legos, where the bricks are atoms and the instructions are written in the laws of quantum physics. This playful manipulation of Chromium Triiodide is just the beginning of a journey toward ultra-efficient, low-power spintronics—devices that use the "spin" of electrons rather than just their charge.

So, the next time you see a pattern shifting on a screen or a set of curtains, think of the tiny magnetic dancers in Chromium Triiodide. They are performing a complex, twisted ballet that could one day power the world. Who knew that just a little bit of a twist could lead to a giant leap in technology? The future of magnetism isn't just about sticking things to your fridge; it's about the beautiful, swirling, oversized patterns created when we let the atoms dance to their own rhythm.

As researchers continue to poke and prod at these two-dimensional wonderlands, we can expect more surprises. Each degree of rotation opens up a new world of possibilities, proving that sometimes, looking at things from a slightly different angle is all it takes to see something magnificent. The giant skyrmions of the atomic world are ready for their close-up, and they’re bringing a whole new meaning to the phrase "putting a spin on things."

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Disco Ball Science: Making Tiny Particles Dance Into Crystals With a Magic Glow!

The Ultimate Micro-Disco: How Light is Playing Architect with the Tiny Universe!

Imagine a world where light creates life-like structures out of thin air!

Imagine for a second that you are the world’s tiniest DJ. Your dance floor isn’t a nightclub in Ibiza; it’s a microscopic drop of liquid. Your dancers? Billions of teeny-tiny particles that are usually just bumping into each other like clumsy toddlers. Normally, these particles have no rhythm and no plan. But then, you turn on the strobe lights, and suddenly, they snap into a perfectly synchronized line dance, forming beautiful, shimmering crystals. This isn't just a fever dream from a sci-fi movie; it’s a groundbreaking new reality where light has become the ultimate remote control for the building blocks of matter!

Researchers have recently discovered a way to play "Simon Says" with microscopic particles by using nothing more than a beam of light. For a long time, scientists have struggled to get these microscopic bits to stay organized. Usually, these particles are like a room full of energetic puppies—impossible to keep in one spot. But by introducing some very special "social directors" into the mix—specifically, light-sensitive molecules—the game has completely changed. These molecules act like a microscopic "mood ring" for the liquid, changing their behavior the moment they are hit by a photon.

The Secret Sauce: Molecular Mood Swings

So, how does this magic trick actually work? It all comes down to chemistry with a serious attitude. These researchers added light-sensitive molecules to a liquid filled with floating particles. Think of these molecules as tiny, invisible hands. When the lights are low, these hands are tucked away, and the particles just drift past each other, oblivious. But the moment you crank up the intensity of the light, those molecules "wake up" and change shape. This transformation acts like a microscopic signal, telling the particles whether they should give each other a giant hug or stay as far away as possible.

By simply turning a dial or changing the pattern of the light, scientists can adjust the "attraction factor." If they want the particles to huddle together and form a solid crystal, they shine a specific pattern of light. If they want that crystal to vanish into thin air, they just flip the switch, and the particles go back to their solo dancing. It’s like having a LEGO set where the bricks only stick together when you point a flashlight at them. This gives us a level of control over matter that we’ve never had before, turning the lab into a high-tech playground of light and shadow.

Real-Time Shape-Shifting

One of the coolest parts of this discovery is that it all happens in real time. We’re not talking about a slow, agonizing process that takes days in a dusty furnace. This is instant gratification science! If the researchers decide they don't like the shape of a crystal, they can simply "draw" a new shape using light patterns, and the particles will scramble to follow the new instructions. They can make crystals grow, shrink, dissolve, or even migrate across the liquid like a tiny, sparkling caravan.

This "light-sculpting" technique is essentially the world’s most advanced etch-a-sketch. Instead of shaking a plastic box to clear the screen, you just change the illumination. This ability to reshape matter on the fly opens up a whole galaxy of possibilities. Imagine being able to "print" a microscopic machine using light, and then, once the job is done, turning the light off and letting the machine melt back into the liquid, ready to be reshaped into something else entirely the next day.

Why Does This Matter for Our Big World?

You might be wondering, "Why should I care about what some invisible dust is doing in a drop of water?" Well, the implications are actually massive! This kind of control could revolutionize how we make everything from medicine to computer screens. Imagine smart materials that can repair themselves when they sense light, or drug-delivery systems that only release their cargo when they are hit by a specific laser beam inside the body. We are looking at a future where we don't just "build" things; we "enlighten" them into existence.

Furthermore, this paves the way for advanced optical technologies. Since these particles can be organized into very specific patterns, they can interact with light in unique ways. We could potentially create lenses that change focus instantly, or displays that are more vivid and energy-efficient than anything we have today. The microscopic disco isn't just a fun party; it's the foundation for the next generation of smart technology that could fit inside the palm of your hand—or even the tip of a needle!

In the end, this research reminds us that science is often about finding new ways to look at the simplest things. Who knew that a little bit of light could be the secret ingredient to taming the chaos of the microscopic world? So, the next time you turn on a lamp, just think: in a lab somewhere, that same light might be telling a billion tiny particles to get in line and build a crystal castle. The future isn't just bright; it's perfectly organized, one photon at a time!

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Disco Ball Science: Making Tiny Particles Dance Into Crystals With a Magic Glow!

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Tiny Magic Seeds Help Solar Panels Sprout Into Efficient Power Superstars!

The Solar Layer Cake: How Tiny Seeds Saved the Sun

Imagine for a second that you’re baking the world’s most important cake. This isn't just any chocolate sponge; this cake has the power to power your house, charge your car, and maybe even save the planet. This is the Perovskite Solar Cell—the "rockstar" of the renewable energy world. It’s thin, it’s flexible, and it’s potentially way cheaper than those old-school silicon panels you see on roofs today. But there’s been a tiny, microscopic problem lurking in the kitchen. Every time scientists tried to bake a big batch, the bottom layer of the cake turned out a bit... crumbly.

In the world of solar tech, we call this the "inverted" structure. It’s like building a house from the roof down. While this design is fantastic for keeping the cell stable and durable, it has a "buried interface"—a secret basement where the materials meet. In the past, this basement was a bit of a mess. The crystals didn’t grow quite right, leaving gaps and rough patches that acted like tiny speed bumps for electricity. If you want to catch sunlight and turn it into power, you don't want speed bumps; you want a high-speed glass highway!

A vision of the future: Pure, glowing energy captured in crystal.

Enter our heroes: the Nanoseeds. But these aren't the kind of seeds you’d plant in your garden to grow prize-winning pumpkins. These are "crystal-solvate nanoseeds." Think of them as tiny, highly-organized coaches for the solar material. When the scientists "bake" the solar film, these nanoseeds act like a GPS, guiding the crystals on exactly where to go and how to grow. They ensure everything stays orderly, dense, and—most importantly—smooth as butter.

The magic happens during the heating process. Usually, when you heat these materials, the liquid solvent escapes too quickly, like steam rushing out of a kettle. This creates chaos and leaves behind a jagged, uneven surface. But these clever nanoseeds hold onto the solvent and release it in a slow, controlled "spa treatment" style. This gives the crystals plenty of time to relax into their perfect positions, creating a film that is much higher quality than anything we've seen before at this hidden layer.

So, what does this actually mean for the rest of us? Well, when the material is smoother and denser, the electrons (the tiny workers that carry electricity) can zip through the cell without getting lost or stuck. This boosted the efficiency of a large "mini-module" to a staggering 23.15%. In the world of solar research, that is a massive "high-five" moment! It proves that we can make these cells bigger without losing their power-generating punch.

For a long time, perovskite cells were great in small, laboratory-sized samples but struggled when they had to grow up and join the real world. This new "seed" method solves the scaling problem. It means we can manufacture larger panels that maintain their efficiency, bringing us one step closer to solar power that is not only cheap and lightweight but also incredibly reliable. We’re moving away from fragile experiments and toward sturdy, high-performance energy tech that can handle the heat.

The durability factor is the cherry on top. Because the crystals are grown so perfectly, they don’t break down as easily when exposed to the elements. These panels are built to last, standing up to the rigors of the outdoors while continuing to pump out clean energy. It’s a win-win-win: higher efficiency, easier manufacturing, and a longer life for the device.

In the end, it turns out that the secret to capturing the massive power of a star 93 million miles away was hidden in a tiny, microscopic seed. By paying attention to the "buried" details and giving our crystals a little bit of guidance, we’ve unlocked a whole new level of solar potential. The future isn’t just bright; it’s smooth, dense, and 23.15% more awesome than it was yesterday!

The sun is shining, the seeds are planted, and the energy revolution is growing faster than ever!

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Tiny Magic Seeds Help Solar Panels Sprout Into Efficient Power Superstars!

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Joseph DeSimone receives $250,000 Kabiller Prize in Nanoscience and Nanomedicine

Northwestern University's International Institute for Nanotechnology (IIN) announced that chemist Joseph M. DeSimone of the University of North Carolina at Chapel Hill is the recipient of the inaugural $250,000 Kabiller Prize in Nanoscience and Nanomedicine. The Kabiller Prize and the $10,000 Kabiller Young Investigator Award in Nanoscience and Nanomedicine were established by the IIN earlier this year through a generous donation from Northwestern trustee and alumnus David G. Kabiller. Recipients are selected by an international committee of experts in the field. Kabiller Prize recipients Joseph DeSimone (third from left) and Warren Chan (far right) were honored by Northwestern's International Institute for Nanotechnology (IIN) at a private dinner Sept. 29. Also pictured are Northwestern trustee and alumnus David G. Kabiller (far left), whose gift established the prizes; Dr. Eric Neilson (second from left), vice president for medical affairs and Lewis Landsberg Dean at Northwestern University Feinberg School of Medicine; and Chad Mirkin (second from right), IIN director and the George B. Rathmann Professor of Chemistry. "These awards were established not only to recognize the people who are designing the technologies that will drive innovation in nanomedicine, but also to educate and shine a light on the great promises of nanomedicine," said Kabiller, co-founder of AQR Capital Management, a global investment management firm in Greenwich, Connecticut. The Kabiller Prize is among the largest monetary awards in the U.S. for outstanding achievement in the field of nanotechnology and its application to medicine and biology. "The world needs more people like David Kabiller," said Chad A. Mirkin, IIN director and the George B. Rathmann Professor of Chemistry in Northwestern's Weinberg College of Arts and Sciences. "He is dedicated to making a difference and to improving the world through advances in science." DeSimone's innovative research applying nanotechnology to medicine captures the vision of the Kabiller Prize. "Joe is a Renaissance scientist, who has made some of the most important advances in the field of nanomedicine," Mirkin said. One of those advances is PRINT (Particle Replication in Non-wetting Templates) technology, invented by DeSimone in 2005. The technology enables the fabrication of precisely defined, shape-specific nanoparticles for advances in disease treatment and prevention. Nanoparticles made with PRINT technology are being used to develop new cancer treatments, inhalable therapeutics for treating pulmonary diseases, such as cystic fibrosis and asthma, and next-generation vaccines for malaria, pneumonia and dengue. "I'm thrilled and humbled to be recognized with the inaugural Kabiller Prize by such a world-class institution as Northwestern's International Institute for Nanotechnology," DeSimone said. "The PRINT technology invented in my laboratory continues to be developed for many different applications to improve human health, and my students are leading that charge. This recognition is really a testament to their brilliant efforts." DeSimone is the Chancellor's Eminent Professor of Chemistry at the University of North Carolina at Chapel Hill (UNC-Chapel Hill). He also is the William R. Kenan Jr. Distinguished Professor of Chemical Engineering at North Carolina State University and of chemistry at UNC-Chapel Hill. DeSimone founded a startup company based on PRINT called Liquidia Technologies that is building on the promise of vaccine clinical trial results. The company already has spun out two more companies to use PRINT to improve human health, one in ophthalmology and one in oral health. "The invention of PRINT technology and its application toward improvements in human health will shape the field of nanomedicine for decades to come and improve the quality of life for many," said Dr. Eric Neilson, vice president for medical affairs and Lewis Landsberg Dean at Northwestern University Feinberg School of Medicine. The International Institute for Nanotechnology also announced that Warren Chan, a professor at the Institute of Biomaterials and Biomedical Engineering at the University of Toronto, is the recipient of the inaugural Kabiller Young Investigator Award. The award recognizes young researchers who have made a recent groundbreaking discovery with the potential to make a lasting impact in the same arena. Chan and his research group have developed an infectious disease diagnostic device for point-of-care use that can differentiate symptoms. A diagnosis occurs when a patient pricks his or her finger, the sample is amplified, and a disease is detected using a smartphone app. (More than one disease can be detected.) Results for patients infected with HIV and hepatitis B are available in less than one hour at 90 percent accuracy, and the diagnostic device costs less than $100. The device currently is being commercialized and could change the way diseases are diagnosed and tracked globally. "I am very honored to receive the Kabiller Young Investigator Award in Nanoscience and Nanomedicine, and I hope this recognition helps to inspire other young people in the field of nanotechnology," Chan said. DeSimone and Chan were celebrated at a private dinner last night in Chicago. The two will be publicly recognized and present their research Oct. 1 at the 2015 IIN Symposium, which will include talks from other prestigious speakers, including 2014 Nobel Prize in Chemistry winner William E. Moerner.

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Brilliant colors from environmentally friendly quantum dots

Quantum dots have made it possible to substantially increase color quality in LCD displays. However, these cadmium-based nanocrystals have proven to be harmful to the environment. Fraunhofer researchers are working together with an industry partner to develop a promising alternative: quantum dots based on indium phosphide. Quantum dots make it possible to display any color in full brilliance. (Image: Fraunhofer IAP) The landscape is breathtaking. Because it is so real, you forget for a moment that the eagle circling the sky is not outside your window, but is instead on your television. Such deceptively realistic images are not only a result of the high resolution displays available on modern devices; the colors play a role as well, and they are becoming ever brighter and richer. This is possible thanks to tiny crystals known as quantum dots (QDs), which have a thickness of merely a few atoms. These nanoparticles located in the backlight units of QD LCD displays offer a cornucopia of colors, but also they possess another extraordinary characteristic. “One big advantage of quantum dots is that their optical properties can be selectively modified by changing their size,” explains Dr. Armin Wedel of the Fraunhofer Institute for Applied Polymer Research IAP in Potsdam, Germany. “This means you no longer have to manufacture three separate materials for the colors red, green and blue; now it is possible to do the job with just one.” This saves both time and money. Over the last several years, Fraunhofer IAP researchers in Potsdam have been developing quantum dots for customers in a wide range of industry sectors. They manufacture the nanoparticles using chemical synthesis and customize them for each application. This initially results in very small particles that radiate blue light. At sizes above approximately 2 nanometers, the color changes to green. The largest of the quantum particles, at 7 nanometers in size, emit within the red spectral range. Currently, Wedel and his team are developing quantum dots for display backlighting on behalf of Dutch company NDF Special Light Products B.V. These quantum dots will improve the color rendering and color realism of the displays. Here, the crystals are manufactured for the different emission colors and embedded in plastics. These plastics are subsequently processed into films and built into the display as a conversion film. Alternative materials based on indium phosphide With this task, researchers are facing a new challenge. The EU Commission is currently considering a ban on cadmium in consumer goods by 2017, because of its damaging effect on the environment. However, it is also considered to be the ideal material for manufacturing the crystals – cadmium-based quantum dots can achieve a narrowband spectrum sharpness of just 20 to 25 nanometers. Display manufacturers around the world are now looking for suitable replacement materials with similar characteristics. Against this backdrop, Fraunhofer IAP looks to be on a promising path. “We are testing quantum dots based on indium phosphide together with NDF Special Light Products,” says Wedel. His team has already managed to achieve a spectral sharpness of 40 nanometers. At first glance, that does not seem too far away from the quality achievable with cadmium-based quantum dots, but the differences in color fidelity are still present. “We see this as a good first milestone, but we are still striving for further improvement,” says Wedel. This effort is set to pay off, as television manufacturers are not the only ones who covet these little color wonders. There is also great market potential for special applications such as medical or aeronautical equipment displays. Furthermore, quantum dots can also increase the efficiency of solar cells, or can be employed in bioanalytics. For such special cases, the optical characteristics of the quantum dots must be precisely configured to the specific application requirements. “We’re in a good position thanks to our extensive experience in manufacturing quantum dots to meet specific customer requirements,” says Wedel.

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