chemistry – Lightsources.org

Researchers identify new material for creating electronic devices

2023/03/272023/03/28

A multidisciplinary research team is developing more efficient and environmentally friendly processes to build light-emitting diodes with the help of the Canadian Light Source (CLS) at the University of Saskatchewan.

Dr. Simon Trudel, professor in chemistry at the University of Calgary and director of the university’s Nanoscience Program, said his team has been studying ways to use amorphous materials to build better “optoelectronic devices” such as organic photovoltaic cells or organic light-emitting diodes (OLEDs), which make possible digital display TV screens, computer monitors and smartphones.

By using a technique called X-ray Absorption Spectroscopy (XAS) at the CLS, Trudel’s team was able to precisely examine the structure of the materials they were experimenting with to create more efficient electronic cells.

Trudel’s team focused on one of the interior layers of the diode called the hole-transport layer, which regulates the movement of electrons — and electrical energy — in a device. They identified an amorphous vanadium oxide compound that could be used for the hole-transfer layer but did not require the standard-but-intense heat treatments to crystallize the material.

Read more on the Canadian Light Source website

Image: Digital displays

#SynchroLightAt75 – Rod MacKinnon’s Nobel Prize in chemistry

2022/06/092022/06/09

Rod MacKinnon – Nobel Prize in chemistry 2003 for work on the structure of ion channels

The structural work of MacKinnon was carried out primarily at the Cornell High Energy Synchrotron Source (CHESS) and the National Synchrotron Light Source (NSLS) at Brookhaven. At the time, CHESS was a first-generation SR source. The award for MacKinnon’s work was the second recognition of SR work by the Nobel Committee. MacKinnon acknowledges the crucial role that the two synchrotron facilities, Cornell Synchrotron (CHESS/MacCHESS) and NSLS, have played in his research on the protein crystallography of membrane channels.

He said, `Without exaggeration that most of what is known about the chemistry and structure of ion channels has come from experiments carried out at these SR centres’.
Rod MacKinnon

Read more on the Nobel Prize website

Image: View showing the location of CHESS, which is underground at Cornell

Credit: Jon Reis

ESRF appoints two new Directors of Research

2022/01/022022/01/04

Gema Martínez-Criado and Annalisa Pastore have been appointed new ESRF directors of research. Martínez-Criado will cover Condensed Matter and Physical and Material Sciences and Pastore Life Sciences, Chemistry and Soft Matter Science.

In its statement, the ESRF Council « unanimously approved the appointments, for a five-year period starting on 01 January 2022, of Dr Gema Martínez Criado, from the Spanish Research Council’s Materials Science Institute of Madrid, as Director of Research for Condensed Matter and Physical and Material Sciences, and of Professor Annalisa Pastore, from King’s College London University, as Director of Research for Life Sciences, Chemistry and Soft Matter Science. » The ESRF Council also « acknowledged the fact that both of these positions were being filled by female candidates of high calibre and expressed the full trust of the Council to continue to lead, in the coming year, the efforts required to fully capitalise on the world leading performances of the EBS storage ring and suite of beamlines.”

Unusual reversibility of molecular break-up of PAHs

2021/02/082021/02/25

By combining the high-resolution x-ray photoelectron spectroscopy at the SuperESCA beamline of Elettra with density functional theory a group of scientists from Italy, UK, Denmark and Germany has shown that the process of hydrogen removal from pentacene molecules adsorbed on Ir(111) follows a reversible chemical route, which allows hydrogen re-attachment to the carbon nanoribbon formed after the thermally induced C–H bond break-up. The thermal dissociation taking place upon controlled annealing can be reversed by cooling the system at room temperature and in a hydrogen atmosphere.

Besides the novelty of the chemical process, this phenomenon could have interesting implications for molecular electronics and for the manipulation of graphene nanoribbons which are known to present higher electron/hole mobilities and better thermal transport when dehydrogenated.

Read more on the Elettra website

Producing less costly, greener hydrogen peroxide

2020/10/212020/10/22

Australian researchers led by the University of New South Wales have used the Australian Synchrotron to understand how the chemical structure of an advanced catalytic material contributes to its stability and efficiency. The approach has the potential to produce hydrogen peroxide (H₂O₂) in a process that is cost-effective with less harm to the environment.

Hydrogen peroxide is an important chemical that used widely in a range of applications, including wastewater treatment, disinfection, paper/pulp bleaching, semi-conductor cleaning, mining and metal processing, fuel cells and in chemical synthesis.

According to an international market research group, IMARC, the global hydrogen peroxide market size was valued at US$4.0 billion in 2017 and is increasing.

Read more on the ANSTO website

Image: The optimized geometry structures of bare CoN₄ moiety and CoN₄ moieties with different coverages of epoxy oxygen. The gray, blue, orange and red balls represent C, N, Co and O atoms, respectively [Reprinted with permission by Creative Commons License: Attribution 4.0 International (CC BY 4.0)]

Milling towards Green Chemistry

2020/08/122020/08/19

Real-time X-ray investigations reveal strong influence of milling equipment on mechanochemical reactions

The result of mechanochemical synthesis can be altered simply by selecting different milling jars and balls. Using the bright X-ray light from PETRA III (shown in green), the team was able to follow the formation of different polymorphs live. (Credit: McGill University, Luzia Germann)

The physical properties of milling jars and balls used in mechanically driven chemical reactions have a considerable influence on the reaction mechanism and outcome. Achieved at PETRA III, this is the result of a time-resolved X-ray study of mechanochemical syntheses. It shows that the material of milling jars, as well as the size and material of the milling balls can be specifically used to control the results of mechanochemical co-crystallisations, as Luzia S. Germann from McGill University (Canada) and co-workers report in the Royal Society of Chemistry’s journal Chemical Science.

Mechanochemistry has recently gained a lot of attention as a cornerstone of green and environmentally-friendly solvent-free synthetic methods. The results of the synchrotron X-ray powder diffraction experiments will contribute to a better understanding of mechanochemical processes and how they can be used in the future to explore the synthesis of new materials.

Read more on the DESY website

Image: The result of mechanochemical synthesis can be altered simply by selecting different milling jars and balls. Using the bright X-ray light from PETRA III (shown in green), the team was able to follow the formation of different polymorphs live. (Credit: McGill University, Luzia Germann)

First direct look at how light excites electrons to kick off a chemical reaction

2020/05/012020/05/14

Light-driven reactions are at the heart of human vision, photosynthesis and solar power generation. Seeing the very first step opens the door to observing chemical bonds forming and breaking.

The first step in many light-driven chemical reactions, like the ones that power photosynthesis and human vision, is a shift in the arrangement of a molecule’s electrons as they absorb the light’s energy. This subtle rearrangement paves the way for everything that follows and determines how the reaction proceeds.
Now scientists have seen this first step directly for the first time, observing how the molecule’s electron cloud balloons out before any of the atomic nuclei in the molecule respond.

While this response has been predicted theoretically and detected indirectly, this is the first time it’s been directly imaged with X-rays in a process known as molecular movie-making, whose ultimate goal is to observe how both electrons and nuclei act in real time when chemical bonds form or break.

>Read more on the LCLS at SLAC website

Image: extract, full image here

Researchers use CHESS to map protein motion

2020/03/092020/04/02

Cornell structural biologists took a new approach to using a classic method of X-ray analysis to capture something the conventional method had never accounted for: the collective motion of proteins.

And they did so by creating software to painstakingly stitch together the scraps of data that are usually disregarded in the process.
Cornell structural biologists took a new approach to using a classic method of X-ray analysis to capture something the conventional method had never accounted for: the collective motion of proteins. And they did so by creating software to painstakingly stitch together the scraps of data that are usually disregarded in the process.
Their paper, “Diffuse X-ray Scattering from Correlated Motions in a Protein Crystal,”published March 9 in Nature Communications.
As a structural biologist, Nozomi Ando, M.S. ’04, Ph.D. ’08, assistant professor of chemistry and chemical biology, is interested in charting the motion of proteins, and their internal parts, to better understand protein function. This type of movement is well known but has been difficult to document because the standard technique for imaging proteins is X-ray crystallography, which produces essentially static snapshots.

Image: This slice through the three-dimensional diffuse map shows intense peaks resulting from lattice vibration, as well as cloudy features caused by internal protein motions.

Shaping attosecond waveforms

2020/02/182020/03/05

Scientists show how to control attosecond light pulses at a free-electron laser.

Chemical reactions and complex phenomena in liquids and solids are determined by the movement and rearrangement of electrons. These movements, however, occur on an extremely short timescale, typically only a few hundred attoseconds (1 attosecond =10^-18 s or one quintillionth of a second). Only light pulses of a comparable duration can be used to take snapshots of the dynamics of electrons. An international team of researchers led by Guiseppe Sansone from the University of Freiburg and including scientists from European XFEL have now, for the first time, been able to reliably generate, control and characterize such attosecond light pulses from a free-electron laser.

“These pulses enable us to study the first moment of the electronic response in a molecule or crystal,” explains Sansone. “With the ability to shape the electric field enables us to control electronic movements – with the long-term goal of optimising basic processes such as photosynthesis or charge separation in materials.”

>Read more on the European XFEL website

Image: Scientists have been able to shape the electric field of an attosecond light pulse.
Credit: Jürgen Oschwald and Carlo Callegari

Inventing a way to see attosecond electron motions with an X-ray laser

2019/12/022019/12/04

Called XLEAP, the new method will provide sharp views of electrons in chemical processes that take place in billionths of a billionth of a second and drive crucial aspects of life.

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory have invented a way to observe the movements of electrons with powerful X-ray laser bursts just 280 attoseconds, or billionths of a billionth of a second, long.

The technology, called X-ray laser-enhanced attosecond pulse generation (XLEAP), is a big advance that scientists have been working toward for years, and it paves the way for breakthrough studies of how electrons speeding around molecules initiate crucial processes in biology, chemistry, materials science and more.
The team presented their method today in an article in Nature Photonics.

“Until now, we could precisely observe the motions of atomic nuclei, but the much faster electron motions that actually drive chemical reactions were blurred out,” said SLAC scientist James Cryan, one of the paper’s lead authors and an investigator with the Stanford PULSE Institute, a joint institute of SLAC and Stanford University. “With this advance, we’ll be able to use an X-ray laser to see how electrons move around and how that sets the stage for the chemistry that follows. It pushes the frontiers of ultrafast science.”

Image: A SLAC-led team has invented a method, called XLEAP, that generates powerful low-energy X-ray laser pulses that are only 280 attoseconds, or billionths of a billionth of a second, long and that can reveal for the first time the fastest motions of electrons that drive chemistry. This illustration shows how the scientists use a series of magnets to transform an electron bunch (blue shape at left) at SLAC’s Linac Coherent Light Source into a narrow current spike (blue shape at right), which then produces a very intense attosecond X-ray flash (yellow).
Credit: Greg Stewart/SLAC National Accelerator Laboratory

A new stable form of plutonium discovered

2019/10/182019/12/17

An international team of scientists, led by the Helmholtz Zentrum Dresden-Rossendorf (HZDR), have found a new compound of plutonium with an unexpected, pentavalent oxidation state.

This new phase of plutonium is solid and stable, and may be a transient phase in radioactive waste repositories. The results are published this week in Angewandte Chemie as a Very Important Paper (VIP). Countries across the globe are making efforts to improve the safety of the nuclear waste storage in order to prevent release of radioactive nuclides to the environment. Plutonium, has been shown to be transported by groundwaters from contaminated sites for kilometres in the form of colloids, which are formed by interaction with clay, iron oxides or natural organic matter.
A team of scientists lead by HZDR studies the chemistry of actinides under environmentally relevant conditions, by synthesizing such compounds, and then studying their electronic and structural behaviour both with advanced synchrotron X-ray methods experimentally as well as theoretically. The latest paper of the international team shows how an experiment seemingly gone wrong leads to a breakthrough: the discovery of a new stable form of plutonium.
It all started when Kristina Kvashnina, physicist from HZDR and based at the ROBL beamline at the ESRF, and her team were trying to create plutonium dioxide nanoparticles using different precursors to be studied at ROBL. When they used the Pu (VI) precursor, they realized that a strange reaction took place during the formation of the plutonium dioxide nanoparticles. “Every time we create nanoparticles from the other precursors Pu(III), (IV) or (V) the reaction is very quick, but here we observed a weird phenomenon half way”, explains Kvashnina. She figured that it must be Pu (V), pentavalent plutonium, a never-observed-before form of the element, after doing a high-energy resolution fluorescence detection (HERFD) experiment at the Pu L3 edge at ROBL.

Image: The team in front of the spectrometer of ROBL. Kristina Kvashnina is the second from the right.

Worldwide scientific collaboration develops catalysis breakthrough

2019/09/302019/10/03

A new article just published in Nature Catalysis shows the simple ways of controlling the structure of platinum nanoparticles and tuning their catalytic properties.

Research led by Cardiff Catalysis Institute (CCI) in collaboration with scientists from Lehigh University, Jazan University, Zhejiang University, Glasgow University, University of Bologna, Research Complex at Harwell (RCaH), and University College London have combined their unique skills to develop and understand using advanced characterisation methods (particularly TEM and B18 at Diamond Light Source), how it is possible to use a simple preparation method to control and manipulate the structures of metal nanoparticles. These metal nanoparticles are widely used by industry as innovative catalysts for the production of bulk chemicals like polymers, liquid fuels (e.g., diesel, petrol) and other speciality chemicals (pharmaceutical products).

Image: Andy Beale works at Diamond Light Source.

Analysis of fingermarks with synchrotron techniques provide new insights

2019/09/062019/09/06

A new study by researchers from Curtin University using the infrared (IR) and X-ray fluorescence microscopy (XFM) beamlines at the Australian Synchrotron has provided a better understanding of the chemical and elemental composition of latent fingermarks.

The findings by lead researchers Prof Simon Lewis and Dr Mark Hackett may provide opportunities to optimise current fingermark detection methods or identify new detection strategies for forensic purposes.
Latent fingermarks are generally described as those requiring some process to make them readily visible to the eye. These fingermarks are typically made up of natural skin secretions, along with contaminants (such as food or cosmetics) picked up from various surfaces.
The detection of latent fingermarks is often crucial in forensic investigations, but this is not always a straightforward task. “We know that there are issues in detecting fingermarks as they get older, and also under certain environmental conditions”, said Lewis, whose main research focus is forensic exchange evidence.

“In order to improve our ability to detect fingermarks, we need to understand the nature of fingermark residue, and this includes both the organic and inorganic components. Many chemical components in fingermark residue are present at very low levels, and we don’t know how they are distributed within the fingermark. This is what took us to the Australian Synchrotron.”

Study reveals ‘radical’ wrinkle in forming complex carbon molecules in space

2019/09/032019/09/05

Unique experiments at Berkeley Lab’s Advanced Light Source shine a light on a new pathway for carbon chemistry to evolve in space.

A team of scientists has discovered a new possible pathway toward forming carbon structures in space using a specialized chemical exploration technique at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). The team’s research has now identified several avenues by which ringed molecules known as polycyclic aromatic hydrocarbons, or PAHs, can form in space. The latest study is a part of an ongoing effort to retrace the chemical steps leading to the formation of complex carbon-containing molecules in deep space. PAHs – which also occur on Earth in emissions and soot from the combustion of fossil fuels – could provide clues to the formation of life’s chemistry in space as precursors to interstellar nanoparticles. They are estimated to account for about 20 percent of all carbon in our galaxy, and they have the chemical building blocks needed to form 2D and 3D carbon structures.

Image: This composite image shows an illustration of a carbon-rich red giant star (middle) warming an exoplanet (bottom left) and an overlay of a newly found chemical pathway that could enable complex carbons to form near these stars.
Credits: ESO/L. Calçada; Berkeley Lab, Florida International University, and University of Hawaii at Manoa.

Brookhaven Lab and University of Delaware begin joint initiative

2019/08/122019/08/15

Through this partnership, scientists from both institutions will conduct collaborative research on rice soil chemistry and quantum materials.

The U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and the University of Delaware (UD) have begun a two-year joint initiative to promote collaborative research in new areas of complementary strength and strategic importance. Though Brookhaven Lab and UD already have a tradition of collaboration, especially in catalysis, this initiative encourages partnerships in strategic areas where that tradition does not yet exist. After considering several potential areas, a committee from Brookhaven and UD selected two projects—one on rice soil chemistry and the other on quantum materials—for the new initiative. For each project, one graduate student based at Brookhaven and one graduate student from UD will work with and be supervised by a principal investigator from each respective institution. The research, to start in October 2019, is funded separately by the two institutions. Brookhaven funding is provided through its Laboratory-Directed Research and Development program, which promotes highly innovative and exploratory research that supports the Lab’s mission and areas for growth.

Image: Principal investigators from Brookhaven Lab and the University of Delaware (UD) will collaborate on two different research projects through a new joint initiative. Brookhaven’s Peter Johnson (left) and UD’s Stephanie Law (second from left) will measure the energy level spectrum of a topological insulator, a new type of material that behaves as an insulator internally but as a conductor on the surface; Brookhaven’s Ryan Tappero (second from the right) and UD’s Angelia Seyfferth (right) will study how toxic and nutrient metals are distributed in rice grain.

Unravelling the growth mechanism of the coprecipitation of iron oxide nanoparticles

2019/06/122019/06/13

Applications involving iron oxide nanoparticles (IONPs) and nanomaterials in general, are expected to provide solutions to many problems in the fields of healthcare, energy and environment. Magnetic nanoparticles (such as IONPs) have been in the exploratory stage for cancer diagnostic (e.g.in the form of magnetic resonance imaging contrast agents) for more than three decades and treatment (e.g.via hypothermia) in the recent decade. However, success stories are rare, partly due to the limited performance of commercially available nanoparticles, related to the particle quality attributes such as size and shape, polydispersity, crystallinity and surface chemistry. Although today’s literature provides many reports on the synthesis of highly complex nanoparticles with superior properties respect the currently approved products, there seems to be a gap to the application of these materials to fully exploit their enhanced capabilities. This is due, at least partly, to obstacles such as low yield and, most importantly, the robustness and reproducibility of the synthesis method. Hence, detailed studies on nanoparticle formation mechanisms are essential to guarantee that successful syntheses are not a “one-off” but can be performed and reproduced at various research institutions at small to large scales. This work presents such a detailed study, unravelling the growth mechanism of the co-precipitation of IONPs in solution with the aid of synchrotron X-Ray diffraction.

>Read more on the Elettra website

Image: TEM images of the nanoparticles formed after 30 s, 1, 2, 3, 4, 5, 7 and 10 min of reaction.