Innovative Navy-funded drone is master of the air and water: Rutgers University

A propeller-driven drone that can fly both in the air and underwater is in development at Rutgers University— a unique vehicle that caught the eye of the U.S. Navy and could be used in search-and-rescue operations and underwater inspections.

The amphibious drone can emerge from the water and then fly through the air, and vice versa, meaning that operators could dispatch it from dry land, send it into water to take a look around, and then bring it back.

F. Javier Diaz, a Rutgers University professor in the department of mechanical and aerospace engineering, explained that the breakthrough in the project’s development came when they decided to give the drone two sets of propellers, one above the other. That helps with the tricky transition from the water to air and back again. While one set of propellers struggles at the air-surface interface, the other set, either all the way in the air or water, works more effectively.

“I think what really impresses people, is how easily it gets out of the water,” Diaz told FoxNews.com. “That’s really where the magic occurs.”

The concept behind the drone is that it could, for example, be launched from shore to inspect underwater portions of a bridge, an oil platform, or a car sunk in a lake or river. This concept promises to be faster that the traditional method of sending a diver out to do an inspection, Diaz said.

The device garnered the interest of the Office of Naval Research, which grantedthe project over half a million dollars last year. “I came to them, showed them the video,” Diaz recounted. “And they were like, ‘We’ve only seen this in movies. We want it.’”

Currently, the drone needs a communications tether, because of the difficulties of talking with the drone underwater— an especially difficult task in a pool, where the walls cause signals to bounce.

KAUST: Using Graphene Quantum Dots to Get More Energy from the Solar Spectrum

Graphene quantum dots can improve the efficiency of silicon solar cells.

 

A graphene quantum dot (white) on top of a solar cell formed by silicon (Si) insulating (ITO) and metal (Au) layers. 
Reproduced with permission from ref 1. © 2016 American Chemical Society

Small flakes of graphene could1 expand the usable spectral region of light in silicon solar cells to boost their efficiency, new research from KAUST shows1.

Solar cell materials have become significantly cheaper to produce in recent years, yet further cost savings are needed to make solar technologies commercially attractive. The prevalence of silicon in solar cells makes them a good target for efficiency enhancement.

“By improving the efficiency of silicon solar cells, we can provide a more cost-effective way for energy production,” said Jr-Hau He, KAUST associate professor of electrical engineering, who also led the research team.

Graphene quantum dots are small flakes of graphene that are useful because of their interaction with light. One of these interactions is optical downconversion, which is a process that transforms light of high energies into lower energy (for example, from the ultraviolet to the visible).

Downconversion can be used to boost solar cells. Silicon absorbs light very efficiently in the visible part of the spectrum, and therefore appears black. However, the absorption strength of silicon for ultraviolet light is much smaller, meaning that less of this light is absorbed, reducing the efficiency of solar cells in that part of the spectrum.
One way to circumvent this problem is the downconversion of ultraviolet light to energies where silicon is a more efficient absorber.

Graphene quantum dots are ideal candidates for this purpose. They are easy to manufacture using readily-available materials such as sugar and by then heating them with microwave radiation. While the dots are almost transparent to visible light, which is important to pass that light through to the solar cell, they are efficient in converting UV light to lower energies.

The researchers integrated the quantum dots on a silicon solar cell device. The efficiency of the solar cells increased in comparison to control samples. For a mature technology to show a clear improvement in efficiency is promising, because it can be produced using an easy manufacturing process.

The test sample solar cells measured so far have not yet been optimized to be closer to the record-breaking performances seen in silicon. The researchers therefore plan to combine some other enhancement technologies previously achieved in similar devices.
He noted. “We have been successfully utilized surface engineering treatments, including fabricating nanostructures and passivation layers, to improve the light harvesting and the electrical properties of solar cells. By integrating these techniques all together, we hope that in the next few years the world record can be broken at KAUST,” he said.

Reference
Tsai, M.-L., Tu, W.-C., Tang, L., Wei, T.-C., Wei, W.-R., Lau, S.P., Chen, L.-J. & He, J.-H. Efficiency enhancement of silicon heterojunction solar cells via photon management using graphene quantum dot as downconverters. Nano Letters 16, 309−313 (2016).| article

Why Scientists Are So Worried about Brexit – Should They Be?

Funding for British research and innovation is only one reason.

Passions are running high ahead of this Thursday’s vote on Britain’s continued membership in the European Union, with the “Brexit” campaign issuing overwrought warnings of five million Turks poised to invade, while the “Bremain” camp—including the government—warns of economic disaster if the country leaves.

It’s just the kind of mudslinging battle that calm, rational scientists normally avoid.
But the British research community sees Brexit as a serious threat to funding and innovation, so it hasn’t stood silently on the sidelines. Polls say 83 percent of British scientists oppose Brexit. 

Many have spoken out: in March all 159 Fellows of the Royal Society at the University of Cambridge called the move “a disaster for British science,” mainly because it would stop young scientists from migrating freely within Europe. A report by the House of Lords reported in April that “the overwhelming balance of opinion from the UK science community” opposed Brexit.

Why? Partly because the EU funds a lot of science and technology research for its member countries, with 74.8 billion euros budgeted from 2014 to 2020. Brexiters say British taxpayers should simply keep their contribution and spend it at home.

They’d take a serious loss if they did. Britain punches above its weight in research, generating 16 percent of top-impact papers worldwide, so its grant applications are well received in Brussels. Between 2007 and 2013, it paid 5.4 billion euros into the EU research budget but got 8.8 billion euros back in grants.

Illustration by Simon Landrein

British labs depend on that for a quarter of public research funds, a share that has increased in recent years. A cut in that funding after Brexit could drag down every field in which British research is prominent—which is most of them.

“It’s not just funding,” says Mike Galsworthy, a health-care researcher at University College London who launched the social-media campaign Scientists for EU. 

“EU support catalyzes international collaboration.” The EU funds research partly to boost European integration: for most programs you need collaborators in other EU countries to get a grant. This isn’t a bad thing, as collaborative work tends to mean more and higher-impact publications.

Brexiters argue that Britain can continue to participate in EU research from outside, under an “association agreement.” Several non-EU countries, like Norway and Tunisia, do that. Would it work for a major research nation?
Ask the Swiss. They are not in the EU, but in 2004 they allowed free movement of people to and from the EU, partly to qualify for EU research programs. In 2014, under the same anti-immigration pressure that pushed Britain to the Brexit vote, 50.3 percent of Swiss voted to repeal that. At the time, no one mentioned how this might affect science.

But Swiss students were summarily dropped from the EU’s Erasmus University exchange program, which is much used by young scientists. Swiss labs are major participants in EU science—one leads its flagship Human Brain Project—and the research ministry stepped in to rescue work stranded as EU funding was abruptly withdrawn. Brussels agreed to give the Swiss temporary “partial association,” with access to some programs mainly for basic research.

That will end in February, however, and the EU insists that for full association, Switzerland, like Norway, must agree to the free movement of people—putting the Swiss back where they started. Without full association, it will have to pay its own way to participate in EU research projects.

“There is no reason to think the U.K. would do any better,” says Athene Donald of Cambridge’s Cavendish Laboratory and the European Research Council. To get an association agreement and EU research funds, Britain would have to agree to free movement of people from the EU, the very thing most Brexiters object to most.

And then the EU-funded science would cost more. Association countries pay into the EU research budget and then compete for joint projects. This takes more admin than simply competing as a dues-paying member, and the country must pay extra for that, making the science some 20 percent more expensive, researchers estimate. Britain would also lose its right, as an EU member, to help decide how the money is spent.

The economic impact of losing access to EU-funded science has not been lost on the Swiss. Polls in May found that now only 21 percent think free movement is a bad thing. Campaigners are organizing another referendum.
Karlheinz Meier, of the University of Heidelberg in Germany, runs the neuromorphic-computing platform for the Human Brain Project, based in Heidelberg—and in Manchester, England. 

If Brexit happens, he expects Britain to find some way to keep participating. “They won’t destroy their research collaboration with Europe,” he says. “It would be crazy.”

But Britain may not have much choice. British chancellor George Osborne said last week that he would have to slash public spending to pay for the costs of Brexit, estimated to total $100 billion by 2020. That, he says, would include hitherto untouchable budgets for health care. Science seems likely to be even more vulnerable to cuts.

High-tech British companies, including Rolls-Royce and BT, have come out against Brexit, as has Coadec, a confederation of small digital startups. All need the single market and common regulations to cut costs, plus free movement—especially for programmers.

Other R&D players made their views clear at hearings in the House of Lords. The EU runs the world’s most advanced magnetic-containment fusion experiments. The JET reactor, in England, has given British physicists and engineers a unique edge in the technology, the U.K. Atomic Energy Agency told the Lords. If the next phase in this program, the ITER reactor in France, ever delivers fusion power, it will take longer without the Brits. We would all lose.

The EU’s 3.3-billion-euro Innovative Medicines Initiative is not now open to the Swiss. The pharmaceutical industry, the largest business investor in British R&D, told the Lords it fears Brexit will mean British labs will follow. Britain is a major player in pharmaceutical research; that means slower progress towards badly needed new drugs.

MIT TECHNOLOGY REVIEW – Guest Contributor Debora MacKenzie June 20, 2016

Flower power—photovoltaic cells replicate rose petals

 With a surface resembling that of plants, solar cells improve light-harvesting and thus generate more power. Scientists of KIT (Karlsruhe Institute of Technology) reproduced the epidermal cells of rose petals that have particularly good antireflection properties and integrated the transparent replicas into an organic solar cell. This resulted in a relative efficiency gain of twelve percent. An article on this subject has been published recently in the Advanced Optical Materials journal.

Photovoltaics works in a similar way as the photosynthesis of plants. Light energy is absorbed and converted into a different form of energy. 

In this process, it is important to use a possibly large portion of the sun’s light spectrum and to trap the light from various incidence angles as the angle changes with the sun’s position. Plants have this capability as a result of a long evolution process – reason enough for photovoltaics researchers to look closely at nature when developing solar cells with a broad absorption spectrum and a high incidence angle tolerance.

Scientists at the KIT and the ZSW (Center for Solar Energy and Hydrogen Research Baden-Württemberg) now suggest in their article published in the Advanced Optical Materials journal to replicate the outermost tissue of the petals of higher plants, the so-called epidermis, in a transparent layer and integrate that layer into the front of solar cells in order to increase their efficiency.

First, the researchers at the Light Technology Institute (LTI), the Institute of Microstructure Technology (IMT), the Institute of Applied Physics (APH), and the Zoological Institute (ZOO) of KIT as well as their colleagues from the ZSW investigated the optical properties, and above all, the antireflection effect of the epidermal cells of different plant species.

 These properties are particularly pronounced in rose petals where they provide stronger color contrasts and thus increase the chance of pollination. As the scientists found out under the electron microscope, the epidermis of rose petals consists of a disorganized arrangement of densely packed microstructures, with additional ribs formed by randomly positioned nanostructures.

In order to exactly replicate the structure of these epidermal cells over a larger area, the scientists transferred it to a mold made of polydimethylsiloxane, a silicon-based polymer, pressed the resulting negative structure into optical glue which was finally left to cure under UV light. “This easy and cost-effective method creates microstructures of a depth and density that are hardly achievable with artificial techniques,” says Dr. Guillaume Gomard, Group Leader “Nanopothonics” at KIT’s LTI.

The scientists then integrated the transparent replica of the rose petal epidermis into an organic solar cell. This resulted in power conversion efficiency gains of twelve percent for vertically incident light. At very shallow incidence angles, the efficiency gain was even higher. The scientists attribute this gain primarily to the excellent omnidirectional antireflection properties of the replicated epidermis that is able to reduce surface reflection to a value below five percent, even for a light incidence angle of nearly 80 degrees.

 In addition, as examinations using a confocal laser microscope showed, every single replicated epidermal cell works as a microlense. The microlense effect extends the optical path within the solar cell, enhances the light-matter-interaction, and increases the probability that the photons will be absorbed.

“Our method is applicable to both other plant species and other PV technologies,” Guillaume Gomard explains. “Since the surfaces of plants have multifunctional properties, it might be possible in the future to apply multiple of these properties in a single step.” The results of this research lead to another basic question: What is the role of disorganization in complex photonic structures? Further studies are now examining this issue with the perspective that the next generation of solar cells might benefit from their results.

 Explore further: Light propagation in solar cells made visible

More information: Ruben Hünig et al. Flower Power: Exploiting Plants’ Epidermal Structures for Enhanced Light Harvesting in Thin-Film Solar Cells, Advanced Optical Materials (2016). DOI: 10.1002/adom.201600046 

You might not have heard of them, but these new materials will change the world

** Contributed by Tim Harper: Entrepreneurial Technology Company Director and Consultant

New materials can change the world. There is a reason we talk about the Bronze Age and the Iron Age. Concrete, stainless steel, and silicon made the modern era possible. Now a new class of materials, each consisting of a single layer of atoms, are emerging, with far-reaching potential. Known as two-dimensional materials, this class has grown within the past few years to include lattice-like layers of carbon (graphene), boron (borophene) and hexagonal boron nitride (aka white graphene), germanium (germanene), silicon (silicene), phosphorous (phosphorene) and tin (stanene). More 2-D materials have been shown theoretically possible but not yet synthesized, such asgraphyne from carbon. Each has exciting properties, and the various 2-D substances can be combined like Lego bricks to build still more new materials.

This revolution in monolayers started in 2004 when two scientists famously created 2-D graphene using Scotch tape—probably the first time that Nobel-prize-winning science has been done using a tool found in kindergarten classrooms. Graphene is stronger than steel, harder than diamond, lighter than almost anything, transparent, flexible, and an ultrafast electrical conductor. It is also impervious to most substances except water vapor, which flows freely through its molecular mesh.

What Is Graphene

 

 

Initially more costly than gold, graphene has tumbled in price thanks to improved production technologies. Hexagonal boron nitride is now also commercially available and set to follow a similar trajectory. Graphene has become cheap enough to incorporate it in water filters, which could make desalination and waste-water treatment far more affordable. As the cost continues to fall, graphene could be added to road paving mixtures or concrete to clean up urban air—on top of its other strengths, the stuff absorbs carbon monoxide and nitrogen oxides from the atmosphere.

 

Other 2-D materials will probably follow the trajectory that graphene has, simultaneously finding use in high-volume applications as the cost falls, and in high-value products like electronics as technologists work out ways to exploit their unique properties. Graphene, for example, has been used to make flexible sensors that can been sewn into garments — or now actually 3-D printed directly into fabrics using new additive manufacturing techniques. When added to polymers, graphene can yield stronger yet lighter airplane wings and bicycle tires.

 

Hexagonal boron nitride has been combined with graphene and boron nitride to improve lithium-ion batteries and supercapacitors. By packing more energy into smaller volumes, the materials can reduce charging times, extend battery life, and lower weight and waste for everything from smart phones to electric vehicles.

Whenever new materials enter the environment, toxicity is always a concern. It’s smart to be cautious and to keep an eye out for problems. Ten years of research into the toxicology of graphene has, so far, yielded nothing that raises any concerns over its effects on health or the environment. But studies continue.

The invention of 2-D materials has created a new box of powerful tools for technologists. Scientists and engineers are excitedly mixing and matching these ultrathin compounds — each with unique optical, mechanical and electrical properties — to produce tailored materials optimized for a wide range of functions. Steel and silicon, the foundations of 20th-century industrialization, look clumsy and crude by comparison.

 

This is part of a series on the top 10 emerging technologies of 2016, developed in collaboration with Scientific American.

Read Genesis Nanotech Online: Latest “Nano-News” and Updates: The “Power of the ‘Nano-Gene Chip’

 

Northwestern University: The Power of the “Gene Chip” Coming to Nanotechnology: Ability to Rapidly Test Millions/ Billions of Nanoparticles at ONE Time

 

Nanotheranostics – The power of nanomedicine

 

 

 

Toronto’s QD (Quantum Dot) Solar Sole Canadian among five winners of solar technology challenge

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Northwestern University: The Power of the “Gene Chip” Coming to Nanotechnology: Ability to Rapidly Test Millions/ Billions of Nanoparticles at ONE Time

A combinatorial library of polyelemental nanoparticles was developed using Dip-Pen Nanolithography. This novel nanoparticle library opens up a new field of nanocombinatorics for rapid screening of nanomaterials for a multitude of properties. (Image: Peng-Cheng Chen/James Hedrick) The discovery power of the “gene chip” is coming to nanotechnology. A Northwestern University research team is developing a tool to rapidly test millions and perhaps even billions or more different nanoparticles at one time to zero in on the best particle for a specific use.

When materials are miniaturized, their properties — optical, structural, electrical, mechanical and chemical — change, offering new possibilities. But determining what nanoparticle size and composition are best for a given application, such as catalysts, biodiagnostic labels, pharmaceuticals and electronic devices, is a daunting task.

“As scientists, we’ve only just begun to investigate what materials can be made on the nanoscale,” said Northwestern’s Chad A. Mirkin, a world leader in nanotechnology research and its application, who led the study. “Screening a million potentially useful nanoparticles, for example, could take several lifetimes. Once optimized, our tool will enable researchers to pick the winner much faster than conventional methods. We have the ultimate discovery tool.”

Using a Northwestern technique that deposits materials on a surface, Mirkin and his team figured out how to make combinatorial libraries of nanoparticles in a very controlled way. (A combinatorial library is a collection of systematically varied structures encoded at specific sites on a surface.) Their study will be published June 24 by the journal Science.

The nanoparticle libraries are much like a gene chip, Mirkin says, where thousands of different spots of DNA are used to identify the presence of a disease or toxin. Thousands of reactions can be done simultaneously, providing results in just a few hours.   Similarly, Mirkin and his team’s libraries will enable scientists to rapidly make and screen millions to billions of nanoparticles of different compositions and sizes for desirable physical and chemical properties.

“The ability to make libraries of nanoparticles will open a new field of nanocombinatorics, where size — on a scale that matters — and composition become tunable parameters,” Mirkin said. “This is a powerful approach to discovery science.”

Mirkin is the George B. Rathmann Professor of Chemistry in the Weinberg College of Arts and Sciences and founding director of Northwestern’s International Institute for Nanotechnology.

“I liken our combinatorial nanopatterning approach to providing a broad palette of bold colors to an artist who previously had been working with a handful of dull and pale black, white and grey pastels,” said co-author Vinayak P. Dravid, the Abraham Harris Professor of Materials Science and Engineering in the McCormick School of Engineering.

Using five metallic elements — gold, silver, cobalt, copper and nickel — Mirkin and his team developed an array of unique structures by varying every elemental combination. In previous work, the researchers had shown that particle diameter also can be varied deliberately on the 1- to 100-nanometer length scale.

Some of the compositions can be found in nature, but more than half of them have never existed before on Earth. And when pictured using high-powered imaging techniques, the nanoparticles appear like an array of colorful Easter eggs, each compositional element contributing to the palette.

To build the combinatorial libraries, Mirkin and his team used Dip-Pen Nanolithography, a technique developed at Northwestern in 1999, to deposit onto a surface individual polymer “dots,” each loaded with different metal salts of interest. The researchers then heated the polymer dots, reducing the salts to metal atoms and forming a single nanoparticle. The size of the polymer dot can be varied to change the size of the final nanoparticle.

This control of both size and composition of nanoparticles is very important, Mirkin stressed. Having demonstrated control, the researchers used the tool to systematically generate a library of 31 nanostructures using the five different metals.

To help analyze the complex elemental compositions and size/shape of the nanoparticles down to the sub-nanometer scale, the team turned to Dravid, Mirkin’s longtime friend and collaborator. Dravid, founding director of Northwestern’s NUANCE Center, contributed his expertise and the advanced electron microscopes of NUANCE to spatially map the compositional trajectories of the combinatorial nanoparticles.

Now, scientists can begin to study these nanoparticles as well as build other useful combinatorial libraries consisting of billions of structures that subtly differ in size and composition. These structures may become the next materials that power fuel cells, efficiently harvest solar energy and convert it into useful fuels, and catalyze reactions that take low-value feedstocks from the petroleum industry and turn them into high-value products useful in the chemical and pharmaceutical industries.

Source: Northwestern University

 

Nanotheranostics – The power of nanomedicine

 

The future of medicine is now dawning upon us.

Nanomedicines demonstrate the capability to enhance drug properties by offering protection from degradation, enabling controlled release and biodistribution and increasing bioavailability. In fact, the term “nanotheranostics” has been proposed to describe a new class of nanomedicines which integrates the simultaneous detection and treatment of a disease. Many creative approaches have been proposed to co-deliver imaging and therapeutic agents too.

World Scientific’s latest book “Nanotheranostics for Personalized Medicine” provides principles of imaging techniques and concrete examples of advances and challenges in the development of nanotheranostics for personalized medicine.

The chapters discuss combining imaging and drug delivery for the treatment of severe diseases, how non-ionizing nanomedicine can be used as contrast agents to increase sensitivity for medical imaging, and how the practical clinical utility is advanced in personalized medicine along with the capabilities and lessons learned for pharmacology and pharmaceutics.

Readers of the book can also expect to read about the application of nanotheranostics in cardiovascular diseases and gene therapy. In addition, there will be a chapter on Plasmonic Nanoparticles-Coated Microbubbles for Theranostic Applications.

Edited by Simona Mura (University Paris Sud XI, France), Patrick Couvreur (University Paris Sud XI, France), Nanotheranostics for Personalized Medicine is on sale in major bookstores, including Amazon, and retails for US$154/ £111.

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How Nanotechnology is Poised to Change Medicine Forever

*** Re-Posted from “Big Think” Science fiction movies such as Ant-Man and Fantastic Voyage excite us about the possibility of shrinking ourselves down to the subatomic level. In the Disney version of The Sword in the Stone, Merlin defeats the sorceress Madam Mim in a shape shifting battle by turning into a microbe which makes […] Click the Link above to Read the Full Article …

Why India Needs Nanotechnology Regulation Before it is Too Late

“For us (India) to fully harness the advances made in nanotechnology and consolidate our leadership in the field, we must work towards building a regulatory framework encompassing public safety.” – Prateek Sibal

India ranks third in the number of research publications in nanotechnology, only after China and the US. This significant share in global nanotech research is a result of sharp focus by the Department of Science and Technology (DST) to research in the field in the country. The unprecedented funding of Rs 1,000 crore for the Nano Mission was clearly dictated by the fact that India had missed the bus on the micro-electronic revolution of the 1970s and its attendant economic benefits that countries like China, Taiwan and South Korea continue to enjoy to this day.

At the same time, the success of the Nano Mission is not limited to research but also involves training the required human resource for further advancement in the field. An ASSOCHAM and TechSci Research study reported in 2014: “From 2015 onwards, global nanotechnology industry would require about two million professionals and India is expected to contribute about 25% professionals in the coming years.”

A missing element in India’s march towards becoming a nanotechnology powerhouse is the lack of focus on risk analysis and regulation. A survey of Indian practitioners working in the area of nano-science and nanotechnology research showed that 95% of the practitioners recognised ethical issues in nanotech research. Some of these concerns relate to the possibly adverse effects of nanotechnology on the environment and humans, their use as undetectable weapon in warfare, and the incorporation of nano-devices as performance enhancers in human beings.

One reason for lack of debate around ethical, and public-health and -safety, concerns around new technologies could be the exalted status that science and its practitioners enjoy in the country. A very successful space program and a largely indigenous nuclear program has ensured that policymakers spend much of their time feting achievements of Indian science than discussing the risks associated with new technologies or improving regulation.

It is not surprising then that products like silver-nano washing machines or insecticides with nanoparticles continue to be sold in the Indian market without any analysis of the risk associated with their use. This – despite the fact that the government itself has acknowledged that nanoparticles of sizes comparable to that of human cells can be deposited in lungs and “may cause damage by acting directly at the site of deposition by translocating to other organs or by being absorbed through the blood.”

A study by the Massachusetts Institute of Technology, Boston, on the toxicity of nano-materials found that carbon nanoparticles inhaled by rats “reached the olfactory bulb and also the cerebrum and cerebellum, suggesting that translocation to the brain occurred through the nasal mucosa along the olfactory nerve to the brain.” This ability to translocate opens up questions about the effect different types of nanoparticles could have on human health.

Many commonly used products have nanoparticles; for instance, titanium dioxide nanoparticles are widely used in sunscreens and cosmetics as sun-protection. In the US, the National Institute of Occupational Safety and Health has issued safe occupational exposure limit of 0.1 mg/m³ for nanoscale titanium dioxide. This was after reports of incidences of lung cancer in rats at doses of 10 mg/m³ and above surfaced. There is also a concern that nano-scale titanium dioxide particles have higher photo-reactivity than coarser particles, and may generate free radicals that can damage cells.

The challenge that remains in front of policymakers is that of regulating a field where vast areas of knowledge are still being investigated and are unknown. In this situation, over-regulation may end up stifling further development while under-regulation could expose the public to adverse health effects. Further, India’s lack of investment in risk studies only sustains the lull in the policy establishment when it comes to nanotech regulations.

The Energy and Resources Institute has extensively studied regulatory challenges posed by nanotechnology and advocates that an “incremental approach holds out some promise and offers a reconciliation between the two schools- one advocating no regulation at present given the uncertainty and the other propounding a stand-alone regulation for nanotechnology.”

Kesineni Srinivas, the Member of Parliament from Vijayawada, has taken cognisance of the need for incremental regulation in nanotechnology from the view point of public health and safety. (Disclosure: The author worked with the Vijayawada MP on drafting the legislation on nanotechnology regulation, introduced in the winter session of Parliament, 2015.)

In December 2015, Srinivas introduced the Insecticides (Amendment) Bill in the Lok Sabha to grant only a provisional registration to insecticides containing nanoparticles with a condition that “it shall be mandatory for the manufacturer or importer to report any adverse impact of the insecticide on humans and environment in a manner specified by the Registration Committee.” This is an improvement over the earlier process of granting permanent registration to insecticides. However, the fate of the bill remains uncertain as only 14 private member bills have been passed in Parliament since the first Lok Sabha in 1952.

More recently, the DST released the ‘Guidelines and best practices for safe handling of nano-materials in research laboratories and industries’. The guidelines which are precautionary in nature lay out methods for safe handling and disposal of nanoparticles by researchers and the industry. Though much delayed, it is a welcome step towards safer nanotechnology research in India.

For us to fully harness the advances made in nanotechnology and consolidate our leadership in the field, we must work towards building a regulatory framework encompassing public safety. Without such a provision, any mishap or catastrophe precipitated by the use of nanotechnology could leave a great opportunity out of our reach.

Prateek Sibal will be joining Sciences Po (the Paris Institute of Political Sciences), Paris, as a Charpak Scholar in 2016.

Perovskite phosphor boosts visible light communication: Flashy nanocrystals help LEDs send data in the blink of an eye

A green-emitting perovskite nanocrystal phosphor mixed with a red-emitting nitride phosphor looks yellow under ambient light (left). When excited by blue laser light, the phosphor combination produces white light (right).

Credit: Osman Bakr

 

Light-emitting diodes (LEDs) are increasingly used to illuminate homes and offices; soon, the same lights could also transmit data to your computer or smartphone in photon pulses so fast the eye can’t see them. But this form of visible light communication faces two key challenges: The light must flicker fast enough to carry sizeable amounts of data; and at the same time it should provide the warm, balanced color tones needed for pleasant ambient lighting.

 

Nanocrystals of cesium lead bromide (CsPbBr₃) could help to solve both problems, according to a team led by Boon S. Ooi and Osman M. Bakr at King Abdullah University of Science & Technology (KAUST). They have found that LEDs coated with the material can reach high data transmission rates of 2 gigabits per second, comparable to the fastest Wi-Fi, while producing a quality of light that matches commercial white-light LEDs (ACS Photonics 2016, DOI: 10.1021/acsphotonics.6b00187).

 

Visible light communication, sometimes called Li-Fi, is already finding real-world applications. Last year, for example, Dutch company Phillips installed a smart LED system in a French supermarket that uses Li-Fi to transmit discount offers to shoppers’ cellphones, based on their location in the store. If data rates could be increased significantly, Li-Fi might add much-needed capacity to congested Wi-Fi networks that rely on radio waves.

 

And since the smart LEDs are doing double duty, by providing both lighting and communication, they offer an economical solution, says Bakr. Ooi adds that these systems do not even need a direct line of sight between LED and computer: “As long as your device can see light, you can detect a signal,” he says.

 

White-light LEDs typically contain a blue LED coated with phosphors that turn some of the light into green and red. But most phosphors take too long to recover between excitation and emission, pulsing no more than a few million times per second. Last year, other researchers showed that polymer semiconductors could reach more than 200 MHz (ACS Photonics2015, DOI: 10.1021/ph500451y).

 

The KAUST team instead turned to CsPbBr₃, part of a family of materials known as perovskites that have become the darling of the photovoltaic research community. Perovskite solar cells have seen remarkable efficiency gains over the past seven years, and the materials are cheap and relatively easy to prepare in solution.

 

The team created nanocrystals of the perovskite, roughly 8 nm across, and found that their green emission faded in just seven nanoseconds. This allowed them to pulse reliably at almost 500 MHz, setting what the researchers believe is a new record for LED phosphors. “It is an extremely impressive and important achievement,” says Ted Sargent of the University of Toronto, who works on optoelectronic materials and has collaborated with the KAUST group in the past.

 

The rapid response is partly due to the size of the crystals, Bakr explains. When blue light excites an electron in the material, it forms an electron-hole pair called an exciton. The confines of the tiny crystal change the exciton’s energy levels, making the electron more likely to recombine with its hole and emit a photon.

 

When the researchers teamed the perovskite phosphor with a commercial red-emitting phosphor and a blue gallium nitride LED, the device produced a warm white light with a color rendering index of 89, as good as white LEDs already on the market (natural sunlight itself is rated at 100). “This quality makes this material ideal for low-power indoor illumination,” Sargent says.

 

Jakoah Brgoch of the University of Houston, who develops novel phosphors for LED lighting, says that it is relatively easy to fine-tune the chemistry of perovskites by substituting different halides or metal ions. “That means there’s a lot of potential to improve these properties,” he says.

Chemical & Engineering News ISSN 0009-2347 Copyright © 2016 American Chemical Society