One of the most common methods of improving the corrosion resistance of steel is coating it with other metals such as aluminum (Al). But the use of Al in marine applications is limited owing to its tendency to react with chloride ions in sea water, leading to corrosion. The addition of other elements, such as magnesium (Mg) and silicon (Si), to form an alloyed coating is a promising way around this problem. But Mg cannot be easily deposited as a coating using the conventional method of dipping the steel into a hot bath of metal salts.
In a recent study published in Corrosion Science, scientists have developed a new protocol for Al-Mg-Si coating of steel. “When I served in the navy, I was constantly looking at rusting machinery. Since then, I have become fully engaged in research on how to produce better anti-corrosive steels,” says Professor Myeong-Hoon Lee of the Korea National Maritime and Ocean University, who guided the study. This study was made available online on September 9, 2021 and was published in Volume 192 of the journal in November 2021.
From textbooks to artwork to newspapers, printed items are a part of our everyday life. But the ink used in today’s printers are limited in colors and resolution. Now in a new study in ACS’ journal Nano Letters, scientists have found a way to expand the printable color spectrum with a novel nanostructure system.
The current color range for computers and printers is based on the sRGB (standard Red Green Blue) color space, which was developed in 1996 by Microsoft and Hewlett-Packard. But the hues in the sRGB system only encompass a subset of colors that the human eye can see. Researchers have been trying to develop a better system to surpass sRGB that would broaden the printable color spectrum while maintaining high resolution.
For example, they have used metallic nanostructures for color printing, but this has resulted in either high-resolution images with less-rich colors, or images with vivid colors but lower resolution. Also, the use of metals like silver and gold would likely be too expensive for wide adoption. So researchers have turned to silicon because it has unique properties that might be optimal for expanding computer and printing colors at a lower price. But so far, silicon color systems have shown poor color saturation and range. So Joel Yang and colleagues wanted to design a novel silicon nanostructure that could potentially overcome these limitations and compete with the sRGB system.
The remarkable properties of 2-D materials—made up of a single layer of atoms—have made them among the most intensely studied materials of our time. They have the potential to usher in a new generation of improved electronics, batteries and sensory devices, among other applications.
One obstacle to realizing applications of these materials is the cost and time needed for experimental studies. However, computer simulations are helping researchers overcome this challenge in order to accurately characterize material structures and functions at an accelerated pace.
At the U.S. Department of Energy’s (DOE) Argonne National Laboratory, researchers have simulated the growth of silicene, a 2-D material with attractive electronic properties. Their work, published in Nanoscale, delivers new and useful insights on the material’s properties and behavior and offers a predictive model for other researchers studying 2-D materials.
Going forward, this model can accelerate researchers’ understanding of 2-D materials, and bring us closer to realizing their applications within a wide range of industries.
Scientists reveal a new nanostructure that could revolutionize technology in batteries and beyond.
New research has identified a nanostructure that improves the anode in lithium-ion batteries
Instead of using graphite for the anode, the researchers turned to silicon: a material that stores more charge but is susceptible to fracturing
The team made the silicon anode by depositing silicon atoms on top of metallic nanoparticles
The resulting nanostructure formed arches, increasing the strength and structural integrity of the anode
Electrochemical tests showed the lithium-ion batteries with the improved silicon anodes had a higher charge capacity and longer lifespan
New research conducted by the Okinawa Institute of Science and Technology Graduate University (OIST) has identified a specific building block that improves the anode in lithium-ion batteries. The unique properties of the structure, which was built using nanoparticle technology, are revealed and explained today (February 5, 2021) in Communications Materials.
Current silicon-based computing technology is energy-inefficient. Information and communications technology is projected to use over 20% of global electricity production by 2030. So finding ways to decarbonise technology is an obvious target for energy savings. Professor Paolo Radaelli from Oxford’s Department of Physics, working with Diamond Light Source, the U.K.“s national synchrotron, has been leading research into more efficient alternatives to silicon. His group’s surprising findings are published in Nature in an article titled "Antiferromagnetic half-skyrmions and bimerons at room temperature.” Some of the antiferromagnetic textures they have found could emerge as prime candidates for low-energy antiferromagnetic spintronics at room temperature.
Researchers have been working for a long time on alternative technologies to silicon. Oxides of common metals such as iron and copper are natural targets because they are already a technology staple, present in silicon-based computers, meaning there is a high chance of compatibility between the two technologies. Although oxides are great for storing information, they are not good at moving information around—a necessity for computation. However, one property of oxides that has emerged is that many are magnetic, which means it might be possible to move magnetic bits around, both in oxides and in other magnets, with very little energy required.
A new publication from Opto-Electronic Advances reviews laser additive manufacturing of Si/ZrO2 tunable crystalline phase 3D nanostructures.
A route for laser nano-printing of 3D crystalline structures was developed employing ultrafast laser lithography, used as additive manufacturing tool for producing true 3D nanostructures, and combined with high temperature thermal post-treatment, converting the printed material into fully inorganic substance.
The inter-disciplinary experimental work revealed the potential of tuning the resulting ceramic structure into distinct crystalline phases, such as cristobalite, SiO2, ZrSiO4, m-ZrO2, t-ZrO2. The proposed approach achieved below 60 nm for individual feature dimensions without any beam shaping or complex exposure techniques, thus making it reproducible with other established standard or custom-made laser direct writing setups. The principle is compatible with commercially available platforms (for instance: Nanoscribe, MultiPhoton Optics, Femtika, Workshop of Photonics, UpNano, MicroLight, and others). Figure 1 graphically summarizes the approach, involved procedure steps, and resulting outcome.
1. The American Edward Goodrich Acheson heated a mixture of clay – aluminium silicate, and powdered coke (carbon) in an iron bowl with a carbon arc, and found shiny hexagonal crystals attached to the carbon electrode. Acheson eventually patented this method for producing powdered silicon carbide (SiC), a compound of silicon and carbon in 1893.
2. The mineral form of silicon carbide is called moissanite and gets its name from Dr Ferdinand Henry Moissan, who first discovered it in the Canyon Diablo Crater in Arizona in 1904.
3. Silicon carbide crystals can be strongly birefringent, meaning the crystals exhibit different refractive indices down different axes.
4. SiC powder production involves the Acheson resistance furnace, produced by the Lely Process. This method creates large single crystals by sublimating silicon carbide powder to form a high-temperature species called silicon dicarbide (SiC2) and disilicon carbide (Si2C).
5. Semiconducting silicon carbide first found application as a detector in early radios at the beginning of the 20thCentury.
To find out more about the history of silicon carbide, read Anna Ploszajski’s Material of the Month feature in our January issue.
A novel technique that nudges single atoms to switch places within an atomically thin material could bring scientists another step closer to realizing theoretical physicist Richard Feynman’s vision of building tiny machines from the atom up.
A significant push to develop materials that harness the quantum nature of atoms is driving the need for methods to build atomically precise electronics and sensors. Fabricating nanoscale devices atom by atom requires delicacy and precision, which has been demonstrated by a microscopy team at the Department of Energy’s Oak Ridge National Laboratory.
They used a scanning transmission electron microscope, or STEM, at the lab’s Center for Nanophase Materials Sciences to introduce silicon atoms into a single-atom-thick sheet of graphene. As the electron beam scans across the material, its energy slightly disrupts the graphene’s molecular structure and creates room for a nearby silicon atom to swap places with a carbon atom.
“We observed an electron beam-assisted chemical reaction induced at a single atom and chemical bond level, and each step has been captured by the microscope, which is rare,” said ORNL’s Ondrej Dyck, co-author of a study published in the journal Small that details the STEM demonstration.
Studies have shown that hybrid powder materials based on natural layered silicates developed by the chemists of the Far Eastern Federal University (FEFU) and the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) decrease the friction ratio in metals sevenfold. These new materials offer new prospects for the development of more efficient anti-friction additives, increasing the durability of spare parts for equipment and vehicles.
The work was carried out by research associates of the School of Natural Sciences and Engineering School of FEFU, as well as the Institute of Chemistry of FEB RAS. The research running led by Nikolay Shapkin, professor of the Department of General, Inorganic, and Organoelement chemistry at FEFU. The results were published in Inorganic Materials.
The scientists report two hybrid composite materials based on natural layered silicates and plant products. The first was obtained from nontronite silicate isolated from Popov Island in the vicinity of Vladivostok and modified with alkaline rice husk hydrolysate. Experiments have shown that applying this powder reduces the deterioration of friction-producing parts 2.5 to seven times. Another material based on vermiculite from Karelia and modified with regular cellulose reduced the friction ratio 1.6 times.
Advanced nuclear magnetic resonance (NMR) techniques at the U.S. Department of Energy’s Ames Laboratory have revealed surprising details about the structure of a key group of materials in nanotechology, mesoporous silica nanoparticles (MSNs), and the placement of their active chemical sites.
MSNs are honeycombed with tiny (about 2-15 nm wide) three-dimensionally ordered tunnels or pores, and serve as supports for organic functional groups tailored to a wide range of needs. With possible applications in catalysis, chemical separations, biosensing, and drug delivery, MSNs are the focus of intense scientific research.
“Since the development of MSNs, people have been trying to control the way they function,” said Takeshi Kobayashi, an NMR scientist with the Division of Chemical and Biological Sciences at Ames Laboratory. “Research has explored doing this through modifying particle size and shape, pore size, and by deploying various organic functional groups on their surfaces to accomplish the desired chemical tasks. However, understanding of the results of these synthetic efforts can be very challenging.”
Electrical engineering researchers have boosted the operating temperature of a promising new semiconductor laser on silicon substrate, moving it one step closer to possible commercial application.
The development of an “optically pumped” laser, made of germanium tin grown on silicon substrates, could lead to faster micro-processing speed of computer chips, sensors, cameras and other electronic devices—at much lower cost.
“In a relatively short time period—roughly two years—we’ve progressed from 110 Kelvin to a record temperature of 270K,” said Shui-Qing “Fisher” Yu, associate professor of electrical engineering. “We are now very close to room-temperature operation and moving quickly toward the application of a material that can significantly increase processing speed with much less power consumption.”
Yu leads a multi-institutional team of researchers on developing a laser injected with light, similar to an injection of electrical current. The improved laser covers a broader wavelength range, from 2 to 3 micrometers, and uses a lower lasing threshold, while capable of operating at 270 Kelvin, which is roughly 26 Farenheit.
Prof. Ye Jichun’s team at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS), collaborating with researchers at the University of Nottingham Ningbo China, has revealed the underlying dynamics of Silicon oxide (SiOx) tunneling junctions, including pinhole formation processes and charge-carrier transport mechanisms. The study was published in Cell Reports Physical Science.
As one of the most promising alternatives to reduce the cost and improve the efficiency of devices, tunnel oxide passivating contact (TOPCon) technology has attracted considerable attention in the photovoltaic (PV) community. However, the physical mechanism of the core structures of TOPCon, i.e., polycrystalline silicon (poly-Si)/ SiOx/ crystalline silicon (c-Si) junctions, has not been clarified, restricting the further improvement of device efficiency.
To address this problem, researchers at NIMTE conducted extensive experiments and simulations, unraveling the underlying charge carrier dynamics of the SiOx tunneling junctions.
Members of the D. V. Skobeltsyn Institute of Nuclear Physic and colleagues from the Faculty of Chemistry of the Lomonosov Moscow State University have developed a new silicon- and germanium-based material that could significantly increase specific characteristics of lithium-ion batteries. The research results have been published in the Journal of Materials Chemistry A.
Lithium-ion batteries are the most popular type of energy storage system for modern electronic devices. They are composed of two electrodes—the negative (anode) and positive (cathode) ones, which are placed into a hermetic enclosure. The space in between is filled with a porous separator, steeped in a lithium ion-conductive electrolyte solution. The separator prevents short circuits between the bipolar electrodes and provides electrolyte volume, necessary for ion transport. Electric current in an external circuit is generated when lithium ions extract from the anode material and move through the electrolyte with further insertion into cathode material. However, the specific capacity of a lithium-ion battery is largely defined by the number of lithium ions that can be accepted and transferred by active materials of the anode and cathode.
The scientists have developed and studied a new anode material that allows energy efficiency of Li-ion batteries to be significantly increased. The material is suitable for utilization in both bulk and thin film Li-ion batteries.
Silicon – the second most abundant element in the earth’s crust – shows great promise in Li-ion batteries, according to new research from the University of Eastern Finland. By replacing graphite anodes with silicon, it is possible to quadruple anode capacity.
In a climate-neutral society, renewable and emission-free sources of energy, such as wind and solar power, will become increasingly widespread. The supply of energy from these sources, however, is intermittent, and technological solutions are needed to safeguard the availability of energy also when it’s not sunny or windy. Furthermore, the transition to emission-free energy forms in transportation requires specific solutions for energy storage, and lithium-ion batteries are considered to have the best potential.
Researchers from the University of Eastern Finland introduced new technology to Li-ion batteries by replacing graphite used in anodes by silicon. The study analysed the suitability of electrochemically produced nanoporous silicon for Li-ion batteries. It is generally understood that in order for silicon to work in batteries, nanoparticles are required, and this brings its own challenges to the production, price and safety of the material. However, one of the main findings of the study was that particles sized between 10 and 20 micrometres and with the right porosity were in fact the most suitable ones to be used in batteries. The discovery is significant, as micrometre-sized particles are easier and safer to process than nanoparticles. This is also important from the viewpoint of battery material recyclability, among other things. The findings were published in Scientific Reports.
Engineers from the Jet Propulsion Laboratory and the California Institute of Technology have developed innovative flat, optical lenses that are capable of manipulating light in ways that are difficult or impossible to achieve with conventional optical devices.
The new lenses are not made of glass. Instead, silicon nanopillars are precisely arranged into a honeycomb pattern to create a “metasurface” that can control the paths and properties of passing light waves.
Applications of these devices include advanced microscopes, displays, sensors, and cameras that can be mass-produced using the same techniques used to manufacture computer microchips.
“These flat lenses will help us to make more compact and robust imaging assemblies,” said Mahmood Bagheri, a microdevices engineer at JPL and co-author of a new Nature Nanotechnology study describing the devices.
“Currently, optical systems are made one component at a time, and the components are often manually assembled,” said Andrei Faraon, an assistant professor of applied physics and materials science at Caltech, and the study’s principal investigator. “But this new technology is very similar to the one used to print semiconductor chips onto silicon wafers, so you could conceivably manufacture millions of systems such as microscopes or cameras at a time.”
Chemists are working to synthesize the next generation of super materials for high-performance electronics, solar cells, photodetectors and quantum computers. While they have made progress with compound materials, they have not yet succeeded in developing unaltered or “freestanding” materials for such devices, according to a review published in the journal Science and Technology of Advanced Materials.
Graphene is a carbon material derived from graphite, the same type of material found in pencils, but it is arranged in a one-atom-thin honeycomb lattice. Discovered in 2004, graphene’s two-dimensional arrangement gives it “extraordinary” properties, including extreme strength and “marvelously high” electron conductivity.
However, the tight lattice lacks a semiconducting bandgap, which is essential for electronic devices. Therefore, scientists have been hunting for alternative materials that have bandgaps, but still have a graphene-like structure.
Much focus has been placed on graphene quantum dots, which are small segments of graphene, about 10 to 100 nm carbon hexagons across and less than 30 atomic sheets thick. To make the dots behave more like 2-D graphene, research teams have added other molecules to change the structure and function of the material.
By encoding information in photons via their spin, “photonic” computers could be orders of magnitude faster and efficient than their current-day counterparts. Likewise, encoding information in the spin of electrons, rather than just their quantity, could make “spintronic” computers with similar a…
We found this video of the weird sound that aerogel makes if you drop it onto a hard surface*. It looks like it would be a squishy gel, but it’s actually hard like glass, and light as a feather. You can light a gas torch on one side and it won’t get hot enough to light a match sitting on the other side! Once you see this amazing substance for yourself, you’ll understand why some people call it “frozen smoke”.
*We don’t recommend dropping Aerogel. Its unique qualities make it fragile and prone to chip or break when roughly handled.
The difference between silicon aerogel an carbon aerogel is that carbon aerogel deforms plastically instead of shattering making it strong as steel and light as air ☼v☼
