ANSTO has contributed to research led by the University of Sydney, involving doping transition metals in a polymorph of bismuth oxide in a search for more structural stability.
Cubic high-temperature polymorph of bismuth oxide, δ-Bi2O3, is the best known oxide ionic conductor but its narrow stability range (729—817 °C), which is close to its melting temperature of 817 °C precludes its practical use.
A large collaboration, led by Professor Chris Ling and Dr. Julia Wind (as part of her Ph.D.) from the University of Sydney involving researchers from ANSTO and two other universities, has achieved the design and understanding of the complex crystal structure and chemistry behind a commensurate structure within the fast-ion conducting stabilised bismuth oxide, co-doped with chromium and niobium, Bi23CrNb3O45.
The study was published in the Chemistry of Materials.
Materials scientists at Duke University computationally predicted the electrical and optical properties of semiconductors made from extended organic molecules sandwiched by inorganic structures.
These types of so-called layered “hybrid organic-inorganic perovskites"—or HOIPs—are popular targets for light-based devices such as solar cells and light-emitting diodes (LEDs). The ability to build accurate models of these materials atom-by-atom will allow researchers to explore new material designs for next-generation devices.
The results appeared online on October 4 in Physical Review Letters.
"Ideally we would like to be able to manipulate the organic and inorganic components of these types of materials independently and create semiconductors with new, predictable properties,” said David Mitzi, the Simon Family Professor of Mechanical Engineering and Materials Science at Duke. “This study shows that we are able to match and explain the experimental properties of these materials through complex supercomputer simulations, which is quite exciting.”
The miniaturization of spectroscopic measurement devices opens novel information channels in medical science and consumer electronics. Scientists of the University of Stuttgart, Germany, developed a 3-D-printed miniature spectrometer with a volume of 100 by 100 by 300 μm3 and a spectral resolution of up to 10 nm in the visible range. This spectrometer can be manufactured directly onto camera sensors, and a parallel arrangement allows for quick (“snapshot”) and low-profile, highly customizable hyperspectral cameras.
Femtosecond direct-laser writing as a 3-D printing technology has been one of the key building blocks for miniaturization in recent years. It has transformed the field of complex micro-optics since the early 2000s. Medical engineering and consumer electronics benefit from these developments. It is now possible to create robust, monolithic and nearly perfectly aligned freeform optical systems on almost arbitrary substrates such as image sensors or optical fibers.
Simultaneously, the miniaturization of spectroscopic measurement devices has been advanced with quantum dot and nanowire technology. These are based on computational approaches, which have the drawback of being calibration-sensitive and require complex reconstruction algorithms.
Scientists boost the accuracy of optical microscopes to image microdroplets in flight and apply the method to analyze the concentration of plastic nanoparticles.
Sneezes, rain clouds, and ink jet printers: They all produce or contain liquid droplets so tiny it would take several billion of them to fill a liter bottle.
Measuring the volume, motion and contents of microscopic droplets is important for studying how airborne viruses spread (including those that cause COVID-19), how clouds reflect sunlight to cool the Earth, how ink jet printers create finely detailed patterns, and even how a soda bottle fragments into nanoscale plastic particles that pollute the oceans.
By improving the calibration of a conventional optical microscope, researchers at the National Institute of Standards and Technology (NIST) have for the first time measured the volume of individual droplets smaller than 100 trillionths of a liter with an uncertainty of less than 1%. That is a tenfold improvement over previous measurements.
Since element 99—einsteinium—was discovered in 1952 at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) from the debris of the first hydrogen bomb, scientists have performed very few experiments with it because it is so hard to create and is exceptionally radioactive. A team of Berkeley Lab chemists has overcome these obstacles to report the first study characterizing some of its properties, opening the door to a better understanding of the remaining transuranic elements of the actinide series.
Published in the journal Nature, the study, “Structural and Spectroscopic Characterization of an Einsteinium Complex,” was co-led by Berkeley Lab scientist Rebecca Abergel and Los Alamos National Laboratory scientist Stosh Kozimor, and included scientists from the two laboratories, UC Berkeley, and Georgetown University, several of whom are graduate students and postdoctoral fellows. With less than 250 nanograms of the element, the team measured the first-ever einsteinium bond distance, a basic property of an element’s interactions with other atoms and molecules.
Researchers at The University of Queensland, New Zealand, and the University of Münster, Germany, have gained insight into the photosynthesis process at a molecular level through understanding the cyclic electron flow supercomplex, which is a critical part of the photosynthetic machinery in plants. The discovery could help guide the development of next-generation solar biotechnologies.
The team purified and characterised the cyclic electron flow supercomplex from micro-algae, and analysed its structure using electron microscopy. The analysis showed how complexes that harvest light become supercomplexes that allow the plant to adapt to varying light conditions and energy requirements.
‘The cyclic electron flow supercomplex is an excellent example of an evolutionarily highly conserved structure,’ says Professor Hippler, the University of Münster. ‘By the year 2050, we will need 50% more fuel, 70% more food, and 50% more clean water. Technologies based on photosynthetic microalgae have the potential to play an important role in meeting these needs’, says Professor Ben Hankamer of the University of Queensland.
The discovery will help guide the design of next generation solar capture technologies based on micro-algae and a wide range of solar driven biotechnologies. This can help produce food, fuel and clean water.
One of the most enduring “Holy Grail” experiments in science has been attempts to directly observe atomic motions during structural changes. This prospect underpins the entire field of chemistry because a chemical process occurs during a transition state—the point of no return separating the reactant configuration from the product configuration.
What does that transition state look like and, given the enormous number of different possible nuclear configurations, how does a system even find a way to make it happen?
Now in the journal Applied Physics Letters, researchers at the Max Planck Institute for the Structure and Dynamics of Matter are reporting “ultrabright” electron sources with sufficient brightness to literally light up atomic motions in real time—at a time scale of 100 femtoseconds, making these sources particularly relevant to chemistry because atomic motions occur in that window of time.
After seeing the first atomic movies of phase transitions in bulk thin films using high-energy (100 kilovolt) electron bunches, the researchers wondered if they could achieve atomic resolution of surface reactions—occurring within the first few monolayers of materials—to gain a better understanding of surface catalysis.
Recipes for three-dimensional (3D) printing, or additive manufacturing, of parts have required as much guesswork as science. Until now.
Resins and other materials that react under light to form polymers, or long chains of molecules, are attractive for 3D printing of parts ranging from architectural models to functioning human organs. But it’s been a mystery what happens to the materials’ mechanical and flow properties during the curing process at the scale of a single voxel. A voxel is a 3D unit of volume, the equivalent of a pixel in a photo.
Now, researchers at the National Institute of Standards and Technology (NIST) have demonstrated a novel light-based atomic force microscopy (AFM) technique – sample-coupled-resonance photorheology (SCRPR) – that measures how and where a material’s properties change in real time at the smallest scales during the curing process.
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.”
Insect infestation is becoming an increasingly costly problem to the forestry industry, especially in areas experiencing increased droughts and hot spells related to climate change. A new terahertz imaging technique could help slow the spread of these infestations by detecting insect damage inside wood before it becomes visible on the outside.
“Our approach could be used to detect early-stage insect infestation on the trunks of trees, in imported wood or on wood products in an early infestation stage,” said research team member Kirsti Krügener, from HAWK University of Applied Science and Arts in Germany. “This could help keep out damaging insects from other countries and stop infestation before it spreads throughout a forest.”
In the Optical Society journal Applied Optics, the researchers report how they used terahertz time-of-flight tomography to noninvasively identify wood samples with otherwise invisible damage from the typographer beetle, which infects spruce and other coniferous trees in Europe. They were also able to reconstruct the internal structure of wood samples.
“Detecting the boreholes of wood-destroying insects is typically done by manually inspecting the wood, and the infected area of the forest to be removed is then estimated,” said Krügener. “To our knowledge, this is the first time a technical method has been used to detect insect boreholes.”
For physicist Percy Zahl, optimizing and preparing a noncontact atomic force microscope (nc-AFM) to directly visualize the chemical structure of a single molecule is a bit like playing a virtual reality video game. The process requires navigating and manipulating the tip of the instrument over the world of atoms and molecules, eventually picking some up at the right location and in the right way. If these challenges are completed successfully, you advance to the highest level, obtaining images that precisely show where individual atoms are located and how they are chemically bonded to other atoms. But take one wrong move, and it is game over. Time to start again.
“The nc-AFM has a very sensitive single-molecule tip that scans over a carefully prepared clean single-crystal surface at a constant height and "feels” the forces between the tip molecule and single atomsand bonds of molecules placed on this clean surface,“ explained Zahl, who is part of the Interface Science and Catalysis Group at the Center for Functional Nanomaterials (CFN), a U.S. Department of Energy (DOE) Office of Science User Facility at Brookhaven National Laboratory. "It can take an hour or days to get this sensor working properly. You can’t simply press a button; fine tuning is required. But all of this effort is definitely worthwhile once you see the images appearing like molecules in a chemistry textbook.”
Compact mass spectrometer more conducive to applications for space exploration, homeland security, and more
Brigham Young University researchers have created a miniaturized, portable version of a tool now capable of analyzing Mars’ atmosphere – and that’s just one of its myriad possible uses.
For decades mass spectrometers have offered a relatively fast and highly sensitive way to analyze and detect chemical compounds. But their bulky size has been a hindrance, limiting their in-field potential.
But after spending 12 years exploring the problem, BYU chemistry professor Daniel Austin, joined by electrical engineering professor Aaron Hawkins and other colleagues, has developed a much smaller spectrometer that still has the capabilities of its larger counterparts.
“The goal was to take what would otherwise be a huge, benchtop instrument to something that’s small enough to carry with you,” said Austin, whose team’s findings were recently published in the Journal of the American Society for Mass Spectrometry.
Perovskite solar cells are an alternative to conventional silicon solar cells, poised to enter the market with their high power-conversion efficiencies (above 22% now) and lower capital expenditure and manufacturing costs.
One of the main methods for depositing perovskite films onto panel structures is a process known as sequential deposition reaction, which was developed in 2013 by Michael Grätzel and co-workers at EPFL. Many studies have attempted to control this process with additives, compositional changes, and temperature effects. However, none of these has provided a complete understanding of the entire sequential deposition reaction. This prevents adequate control over film quality, which determines the performance of the solar cell.
A study by Michael Grätzel and Amita Ummadisingu at EPFL now offers the most systematic and full study of the sequential deposition reaction to-date. The scientists began with X-ray diffraction analysis and scanning electron microscopy to study in depth the crystallization of lead iodide (PbI2), which is the first stage of the reaction. They then used, for the first time, SEM-cathodoluminescence imaging to study the nano-scale dynamics of perovskite film formation.
“We have combined two powerful tools to obtain compositional information about the surface of the film during perovskite formation,” says Amita Ummadisingu. “This technique enables us to achieve stunning nano-scale resolution meaning that we can see, for the first time, that mixed crystalline aggregates composed of perovskite and PbI2 are formed during the reaction.”
Images reveal battery materials’ chemical reactions in five dimensions – 3D space plus time and energy The chemical phase within the battery evolves as the charging time increases. The cut-away views reveal a change from anisotropic to isotropic phase boundary motion. Researchers at the U…
Australian researchers and their colleagues from Russia and China have shown that it is possible to study the magnetic properties of ultrathin materials directly, via a new microscopy technique that opens the door to the discovery of more two-dimensional (2D) magnetic materials, with all sorts of potential applications.
Published in the journal Advanced Materials, the findings are significant because current techniques used to characterise normal (three-dimensional) magnets don’t work on 2D materials such as graphene due to their extremely small size – a few atom thick.
“So far there has been no way to tell exactly how strongly magnetic a 2D material was,” said Dr Jean-Philippe Tetienne from the University of Melbourne School of Physics and Centre for Quantum Computation and Communication Technology.
“That is, if you were to place the 2D material on your fridge’s door like a regular fridge magnet, how strongly it gets stuck onto it. This is the most important property of a magnet.”
To address the problem, the team, led by Professor Lloyd Hollenberg, employed a widefield nitrogen-vacancy microscope, a tool they recently developed that has the necessary sensitivity and spatial resolution to measure the strength of 2D material.
From common soot to precious diamonds, carbon is familiar in many guises, but there have been little more than glimpses of carbon in the liquid form. Researchers at the FERMI Free Electron Laser (FEL) source have now not only generated a liquid carbon sample, but have characterized its structure, tracking the ultrafast rearrangements of electron bonding and atomic coordinates that take place as their carbon samples melt. “As far as I know, that is the fastest structural transition in condensed matter,” says Emiliano Principi, principal investigator on the project.
The work fills in some of the gaps in the element’s phase diagram—a plot of its phases at different temperatures and pressures. Despite the ubiquity of carbon and the interest it garners in so many facets of science—from sensorsandsolar cellstoquantum computingandspace rocket protection systems—knowledge of its phase diagram remains patchy. Typically, as soon as solid carbon can’t take the heat, it sublimates to gas. For other materials, researchers can enroll high-pressure cells to prevent the sample expanding straight into a gas at high temperatures, but these are usually diamond, precisely the element the conditions are designed to melt.
Wettability of a material is the ability of a liquid to maintain contact with a solid surface, and it is proportional to hydrophilicity and inversely proportional to hydrophobicity. It is one of the most important properties of a solid, and understanding the wettability of different substrates is essential for various industrial uses, such as desalination, coating agents, and water electrolytes.
So far, studies on the wettability of substrates have mainly been measured at the macroscopic level. The macroscopic measurement of wettability is typically determined by measuring the water contact angle (WCA), which is the angle a water droplet makes with respect to the surface of the substrate. However, it is currently very difficult to accurately measure what happens at the interface between a substrate and water at the molecular level.
Currently used microscopic measurement techniques, such as reflection-based infrared spectroscopy or Raman spectroscopy, are incapable of selectively observing the interfacial water molecules. Since the number of water molecules in the entire bulk of the liquid is much larger than the molecules that are making contact with the surface, the signal of interfacial water molecules is obscured by the signal of water molecules in the bulk liquid.
