While tracking electrons moving through exotic materials, researchers have discovered intriguing properties not found in conventional, silicon-based semiconductors.

Unlike current silicon-based electronics, which shed most of the energy they consume as waste heat, the future is all about low-power computing. Known as spintronics, this technology relies on a quantum physical property of electrons—up or down spin—to process and store information, rather than moving them around with electricity as conventional computing does.

On the quest to making spintronic devices a reality, scientists at the University of Arizona are studying an exotic crop of materials known as transition metal dichalcogenides, or TMDs. TMDs have exciting properties lending themselves to new ways of processing and storing information and could provide the basis of future transistors and photovoltaics—and potentially even offer an avenue toward quantum computing.

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New graphene printing technology can produce electronic circuits that are low-cost, flexible, highly conductive and water repellent, researchers report.

The nanotechnology “would lend enormous value to self-cleaning wearable/washable electronics that are resistant to stains, or ice and biofilm formation,” according to the new paper.

“We’re taking low-cost, inkjet-printed graphene and tuning it with a laser to make functional materials,” says Jonathan Claussen, an assistant professor of mechanical engineering at Iowa State University, an associate of the US Department of Energy’s Ames Laboratory, and the corresponding author of the paper in the journal Nanoscale.

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Researchers have found a way to get electrons to travel much farther than was previously thought possible in materials for organic solar cells. This advance could make these solar cells much more useful than inorganic alternatives.

“For years, people had treated the poor conductivity of organics as an unavoidable fact, and this shows that that’s not always the case,” says research leader Stephen Forrest, professor of engineering at University of Michigan.

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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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Incorporating organic electronic materials in the field of bioelectronics has indicated promising potential in interfacing with biological systems, including neuroscience applications. Researchers from Linköping University are taking a major step forward in that work with their development of the world’s first complementary electrochemical logic circuits that can function for long periods of time in water.

While the first printable organic electrochemical sensors appeared as early as 2002, significant advancements have developed in a few years. Organic components such as light-emitting diodes and electrochemical displays are already commercially available.

This from Linköping University:

The dominating material used until now has been PEDOT:PSS, which is a p-type material, in which the charge carriers are holes. In order to construct effective electron components, a complementary material, n-type, is required, in which the charge carriers are electrons.

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A new method to quickly produce fibers from carbon nanotubes is both handmade and high tech.

The method allows researchers to make short lengths of strong, conductive fibers from small samples of bulk nanotubes in about an hour.

In 2013, Rice University chemist Matteo Pasquali found a way to spin full spools of thread-like nanotube fibers for aerospace, automotive, medical, and smart-clothing applications. The fibers look like cotton thread but perform like metal wires and carbon fibers.

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Researchers have found an explanation for why a certain class of quantum dots shines with such incredibly bright colors.

The nanocrystals in question contain caesium lead halide compounds arranged in a perovskite lattice structure. Three years ago, Maksym Kovalenko, a professor at ETH Zurich and the Swiss Federal Laboratories for Materials Science and Technology (Empa), succeeded in creating nanocrystals from the same semiconductor material.

“These tiny crystals have proved to be extremely bright and fast emitting light sources, brighter and faster than any other type of quantum dot studied so far,” says Kovalenko.

By varying the composition of the chemical elements and the size of the nanoparticles, Kovalenko also  produced a variety of nanocrystals that light up with the colors of the entire visible spectrum. These quantum dots could be used as components for future light-emitting diodes (LEDs) and displays.

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Sensors on tape that attach to plants yield new kinds of data about water use for researchers and farmers.

“With a tool like this, we can begin to breed plants that are more efficient in using water,” says Patrick Schnable, plant scientist at Iowa State University. “That’s exciting. We couldn’t do this before. But, once we can measure something, we can begin to understand it.”

The tool making these water measurements possible is a tiny graphene sensor that can be taped to plants—researchers call it a “plant tattoo sensor.” Graphene is an atom-thick carbon honeycomb. It’s great at conducting electricity and heat, and is strong and stable. The graphene-on-tape technology in this study has also gone into wearable strain and pressure sensors, including sensors for a “smart glove” that measures hand movements.

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By: Jack Barkenbus, Vanderbilt University

Every day about 100 people die in car crashes on U.S. roads. That death toll is a major reason why both Congress and the Trump administration are backing automotive efforts to develop and deploy self-driving cars as quickly as possible.

However, officials’ eagerness far exceeds the degree to which the public views this as a serious concern, and overestimates the public’s willingness to see its driving patterns radically altered. As those of us involved in studies of technology and society have come to understand, foisting a technical fix on a skeptical public can lead to a backlash that sets back the cause indefinitely. The backlash over nuclear power and genetically modified organisms are exemplary of the problems that arise from rushing technology in the face of public fears. Public safety on the roads is too important to chance consumer backlash.

I recommend industry, government and consumers take a more measured and incremental approach to full autonomy. Initially emphasizing technologies that can assist human drivers – rather than the abilities of cars to drive themselves – will somewhat delay the day all those lives are saved on U.S. roads. But it will start saving some lives right away, and is more likely to avoid mass rejection of the new technology.

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A new chemical sensor prototype will be able to detect “single-fingerprint quantities” of chemicals and other substances at a distance of more than 100 feet—and its creators are working to make it the size of a shoebox.

The device could potentially identify traces of drugs and explosives, as well as speed up the analysis of certain medical samples. A portable infrared chemical sensor could be mounted on a drone or carried by users such as doctors, police, border officials, and soldiers.

The device’s sensor is made possible by a new optical-fiber-based laser that combines high power with a beam that covers a broad band of infrared frequencies—from 1.6 to 12 microns, which covers the so-called mid-wave and long-wave infrared.

“Most chemicals have fingerprint signatures between about 2 and 11 microns,” says researcher Mohammed Islam, who developed the laser. “Hence, this wavelength range is called the ‘spectral fingerprint region.’ So our device enables identification of solid, liquid, and gas targets based on their chemical signature.”

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