MRS TV speaks with Kwadwo Osseo-Asare, the recipient of the 2022 MRS Impact Award for sustained contributions to building a global materials science and engineering community that spans continents from Africa to the Americas.
Annamaria Petrozza of the Italian Institute of Technology discussed her talk presentation, “Defects Activity in Metal Halide Perovskites”. Petrozza was awarded the 2022 MRS Innovation in Materials Characterization Award For the development and innovative use of time-resolved carrier dynamics measurements, from sub-picoseconds to milliseconds, to fundamentally advance our understanding of the photo-physics of metal-halide perovskites, leading to materials and devices of improved stability.
MRS TV talks to Dr. Petrozza about the work that led to this award.
MRS TV speaks with the 2022 MRS Mid-Career Researcher Award winner, Molly Stevens of Imperial College London. Dr. Stevens receives this award for innovative biosensing nanomaterials technologies for point-of-care disease diagnostics.
Written by Rahul Rao
MRS honored this year’s award recipients for work ranging from ultrafast camera shots to disease-diagnosing nanoparticles to a web of intercontinental outreach. MRS Awards Committee Chair Suveen Mathaudhu of the Colorado School of Mines hosted the awards session. As in past years, each recipient proceeded to deliver a talk about their work. Afterwards, the awardees sat for a panel discussion with the audience.
Annamaria Petrozza of the Italian Institute of Technology received the Innovation in Materials Characterization Award. She talked about her group’s work with a class of materials known as metal halide perovskite semiconductors. Used in devices such as solar cells, these materials have some unusual properties. Even with defects in the materials’ structures, electrons carrying charge lasted surprisingly long: a property that is often a marker of more efficient devices.
Petrozza said her group’s work has focused on trying to understand what could cause those long-lived electrons. Theoretically, it was possible that the defects could trap electrons and temporarily store them. By setting up an ultrafast camera, Petrozza and her colleagues were able to provide evidence that the electrons were indeed being trapped. She said the group was now working on finding how metal halide perovskites could be more stable, and she said they hoped to gain more insight on their structure by probing them with ultraviolet light.
Molly Stevens of Imperial College London received the Mid-Career Researcher Award for her group’s work with applying nanomaterials to diagnosing diseases. Her group, she said, was an interdisciplinary collection of everyone from materials scientists to surgeons to physicists to mathematicians. Part of their work sought to design nanoparticles that could diagnose diseases, including HIV, Ebola, tuberculosis, and Covid-19, earlier than healthcare workers or technologies can do today.
One problem with trying to design nanoparticles, she said, is that there previously had been few techniques that could study one nanoparticle at a time. So, Stevens spoke about how her group had invented a new method: corralling a nanoparticle in an optical trap, allowing researchers to measure the particle’s individual chemistry. This method promised to ease the task of developing more sensitive nanoparticles, she said, and it would soon be available commercially.
Prineha Narang of Harvard University received the Outstanding Early Career Investigator Award. She talked about her group’s work with materials that display quantum properties. In particular, shining light – everything from microwaves to x-rays – can illuminate such quantum materials into new states of matter. That poses a challenge, Narang said, because traditional methods of examining a quantum material work best when the material is in equilibrium, and these new states of matter are often far from equilibrium.
Therefore, Narang talked about how her group was thinking about how to take existing approaches – ranging from condensed-matter techniques examining groups of atoms, to methods that look at individual atoms – and modifying them to look at states of matter that were not in equilibrium. By combining these various methods, she said, future researchers would be able to investigate these bright new phases of matter.
Kwadwo Osseo-Asare of The Pennsylvania State University received the MRS Impact Award for his contributions to building a global materials science community. He delivered a talk titled, in translation, “When a single tree encounters strong wind, it breaks,” a proverb from the Ga language in Ghana. To Osseo-Asare, this proverb signifies the value of the academic family. He said he first learned that value in his early years as a graduate student and as an early-career researcher studying applications of colloids, when his students helped him acquire a valuable grant.
Osseo-Asare then raised another Ghanaian proverb, this one from the Akan language: “It is through the tree that the vine sees the sky,” In this spirit, Osseo-Asare sees the academic family as crucial to his outreach work. He spoke of how he, his students, and their students in turn had all helped cultivate collaborations with institutions from Nigeria to Brazil and from Japan to Ghana. African proverbs like these, he said, can help teach people about materials, promoting understanding and creativity amongst teachers and students alike.
Aditya Sood of the SLAC National Accelerator Laboratory received the MRS Postdoctoral Award. Sood talked about how he and his colleagues wanted to watch the processes at work inside computing devices as they switched from one state to another. To do this, they designed an ultrafast camera that shot electrons through a material and captured the resulting diffraction pattern. That camera was sensitive down to 100-femtosecond-long “frames.”
Sood compared their camerawork to filming a horse in motion to see if the animal could lift all four hooves off the ground at once. Sood and his colleagues’ horse was vanadium dioxide, a semiconductor, as it switched between two states. Thanks to their camera’s speed, Sood’s group was able to see, in detail, a brief intermediate state between the two. Sood said that stabilizing that intermediate state may help create more energy-efficient electronic switches.
The second recipient of the MRS Postdoctoral Award was Mattia Biesuz of the University of Trento, who was unfortunately unable to appear in person. Biesuz earned the award for “flash sintering phenomena and processes in ceramics.”
The Innovation in Materials Characterization Award has been endowed by Dr. Gwo-Ching Wang and Dr. Toh-Ming Lu. The Mid-Career Researcher Award is made possible through an endowment established by MilliporeSigma (Sigma-Aldrich Materials Science).
Sossina Haile, Northwestern University
Vignettes in Solid State Electrochemistry for Sustainable Energy Technologies
Written by Don Monroe
Warming and precipitation changes will hit equatorial regions the hardest, said Sossina Haile of Northwestern University, and developed countries have the responsibility and resources to explore technologies to deal with the changes they are largely responsible for. Her group looks for overlaps between energy technologies, fundamental materials properties, and fabrication of precise structures to get meaningful measurements. Haile presented four examples of solid-state phenomena at successively higher temperatures, which draw on understanding of materials chemistry, thermochemistry, and electrochemistry.
Her first vignette concerned the use of superprotonic conductors at “warm” temperatures. Specifically, the electrical conductivity of cesium dihydrogen phosphate jumps up by three or four orders of magnitude when heated above about 250°C, reflecting rapid reorientation of proton-bearing phosphate groups and the transfer of the proton between neighboring phosphates. One challenge with these materials is that they are water soluble, so they need to be stabilized using a high-humidity environment.
Haile’s research team exploited the proton conduction of this solid acid as the central layer of fuel cells that generate electricity directly from the reaction of hydrogen with oxygen. In this device every electron brings a hydrogen atom, she said, meaning a 100% faradaic efficiency. Adding a reforming catalyst at the anode side creates a cell that uses alcohols as the starting source for hydrogen. There may even be ways to use liquid ammonia as a hydrogen source. “Superprotonic conductors are pure proton conductors,” she said, and “have lots of intriguing technological possibilities.”
Haile’s second, “hot” vignette involved protonic ceramic electrolytes, such as doped barium zirconate, a perovskite. She described a reversible cell, which can act either as a fuel cell or for electrolysis, similar to a storage battery. The conductivity of this material is good at temperatures around 500°C.
The proton conducting material avoids many of the downsides seen in oxygen-conducting systems, she said, including degradation of materials and dilution of the fuel source. However, current materials are hampered by some electronic conduction.
In her third example, Haile described studies of ceria-zirconia materials, which are commonly used in catalysis at “hotter” temperatures. Although the oxidation state of zirconium is largely fixed, that of cerium can be 3+ or 4+. The researchers used glancing-angle x-ray absorption near-edge structure (XANES) to find that the 3+ state of cerium is much more prominent at the surface. Somewhat surprisingly, this result was largely independent of the zirconium concentration and of the surface orientation. “The relationship between the Ce3+ on the surface and catalytic activity remains a mystery,” she said.
The final example involves not electrochemistry but thermochemistry, thermally cycling non-stoichiometric perovskites to produce hydrogen. At “fiery” temperatures as high as 1500°C, entropy drives thermal reduction and oxygen release from the materials. Upon quenching to a lower temperature, perhaps 800°C, the material reacts with steam and CO2 to form H2 and CO.
The second process is driven primarily by enthalpy. This driver led Haile and her team to explore materials such as “STM55,” SrTi0.5Mn0.5O3. To achieving the right balance between reduction and oxidation to improve the production rate per cycle, she said, “It’s really important to recognize that the thermodynamics govern the fuel production rate. The whole thing is about thermodynamics.”
Still, “[we’re] waiting for the mechanical engineers to design the reactors so we can design the materials, and the mechanical engineers are saying ‘What can your material do for us, so we can design the reactor,’” she said. “It’s all a bit of a Catch-22.”
The Kavli Foundation is dedicated to advancing science for the benefit of humanity, promoting public understanding of scientific research and supporting scientists and their work.
Andreas Lendlein, Helmholtz-Zentrum Hereon
Bio-inspired and computer-supported design of modulated shape changes in polymer materials
Written by Alison Hatt
In the MRS Communications lecture on Monday, Andreas Lendlein of the University of Potsdam, Germany, delivered a fast-paced overview of his research on shape-memory polymer materials, with a special focus on his recent work on a system inspired by the Venus flytrap plant. Shape memory polymers are polymers that, having been deformed, can be returned to their original shape through application of an external stimulus, such as a change in temperature.
Lendlein started with his work in biomedical applications, where he looked for ways to support the surgeons who do minimally invasive surgeries using micro-instruments. Among the many challenges of doing procedures like colon surgery with micro-instruments is the need to precisely tie sutures inside the body. To that end, Lendlein and colleagues developed sutures made of shape-memory polymers that would tighten themselves into pre-programmed knot shapes in response to the temperature of the body. The resulting knots exert pressures five times higher than those tied by hand.
Moving on to the realm of automotive applications, Lendlein shared his work developing a triple-shape polymer that can change from one shape to another, both fixed by physical crosslinking, and then to a third shape defined by covalent crosslinking. Such a material, which could be incorporated into the body of a vehicle, can be deformed and then restored to the desired shape using something as simple as a heat gun. Lendlein also discussed the development of shape-memory polymers for self-healing coatings for cars, in which scratches could essentially iron themselves out with a little heat.
Lendlein presented several other examples from his work with shape-memory polymers inspired by and developed for various applications: photo-sensitive shape memory polymers were developed to close tiny lamella in front of a window to selectively block light on bright, sunny days for active light control; fibers coated in a shape memory polymer enabled an origami hand robot in which the fingers can bend and stretch in multiple directions; and non-continuous actuators with fine control were created by combining shape memory polymers responsive to different temperatures in a device.
For the final section of the talk, Lendlein turned to his work on bio-inspired materials, where he uses the plant kingdom as inspiration. He discussed the Venus flytrap plant, which can snap shut in 300 milliseconds when triggered by an insect brushing against fine hairs inside the trap and displacing water on its surface, switching the lobes from a mono-stable to a bi-stable state. Using that biological system as a starting point, he and colleagues tried to mimic it in a technical system, modeling and then fabricating three-dimensional films of shape-memory polymer in the form of truncated tetrahedra. Informed by their models, the researchers determined that when the slope of the tetrahedra was 30 degrees, the film was mono-stable, but it was bi-stable when the slope was 45 degrees. They were then able to program the 30-degree film to take a 45-degree form at a lower temperature, allowing them to switch between mono- and bi-stable states by changing the temperature.
In closing, Lendlein encouraged researchers to approach with open eyes the rich Hawaiian environment outside the conference center, receptive to the hundreds of thousands of possible ideas to be found there in nature.
The MRS Graduate Student Awards are intended to honor and encourage graduate students whose academic achievements and current materials research display a high level of excellence and distinction. In addition to the MRS Graduate Student Gold and Silver Awards, the Arthur Nowick Graduate Student Award, which honors the late Dr. Arthur Nowick and his lifelong commitment to teaching and mentoring students in materials science, will be presented to a GSA finalist who shows particular promise as a future teacher and mentor.
Massachusetts Institute of Technology
Harvard University
Massachusetts Institute of Technology
Harvard University
The University of Texas at Austin
Massachusetts Institute of Technology
Nowick Award
Massachusetts Institute of Technology
California Institute of Technology
University of California, Berkeley
University at Buffalo
Seoul National University
The University of Texas at Austin
University of Virginia
Massachusetts Institute of Technology
University of Pennsylvania
University of California, Berkeley
Written by Sophia Chen
At each conference, MRS invites award recipients to deliver a short talk about their research. This year’s speakers presented topics ranging from quantum theoretical simulation to more environmentally sustainable cement. The panel was moderated by MRS Awards Committee chair Suveen Mathaudhu of the University of California, Riverside.
Emily Carter of the University of California, Los Angeles, presented about theoretical research for predicting materials properties, particularly for carbon mitigation purposes. She uses theoretical methods to identify catalysts for recycling carbon dioxide into chemical feedstocks or to devise carbon sequestration methods.
These applications involve electron transfer and electronic excited states, both of which are not well described by density functional theory, the primary theoretical framework for modeling quantum processes, says Carter. Instead, she studies embedded correlated wavefunction (ECW) theory. In one study, she found that ECW described carbon dioxide reduction on a copper electrode more accurately than density functional theory.
Yury Gogotsi of Drexel University presented research on a class of two-dimensional materials known as MXenes (pronounced “max-eens”) for energy storage. The basic unit of these materials is a transition metal bonded to a carbon or nitrogen. To tune the material’s properties, you can swap out the atoms exposed at the material’s surface.
Gogotsi says MXenes could be suitable for many different applications. It has already outperformed all other known materials for electromagnetic interference shielding, he said. In addition, MXenes can be used for antennas and communications. It can also be knitted into fabrics for wearable electronics.
Susan Bernal Lopez of the University of Leeds presented her research on more environmentally sustainable concrete. Concrete is the most widely used material in the world after water, and making it produces a significant amount of carbon dioxide. Bernal is studying how to reduce CO2 during production.
In one case, she is looking into a class of materials known as alkali-activated cement to replace Portland cement, the glue that keeps concrete together. Alkali-activated cement can be made by combining an aluminosilicate source, such as volcanic ash or byproducts from coal combustion, with an alkali source. Alkali-activated cement would produce half or less of the hundreds of kilograms of carbon dioxide that Portland cement produces.
Bernal’s group is working to characterize alkali-activated cement. She has studied how impurities affected the performance of the cement. She has also studied the evolution of pores within paste after mixing for identifying strategies to make concrete more durable.
Stafford Sheehan, chief technology officer of Air Company, presented his company’s efforts to convert carbon dioxide into alcohol-containing products. These products range from vodka and hand sanitizer to aviation fuel and fragrances. The company operates three facilities: a catalyst lab for optimizing catalysts in New Jersey, a pilot facility for testing reactions, and a production facility that operates 24 hours a day, seven days a week.
Air Company is working to scale up their production, said Sheehan. They have operated a system that can handle one tonne of carbon dioxide per day. Now, they are striving to scale up to 500 tons per day by 2024 and eventually 10,000 tons per day by 2027.
Dasha Nelidova, a postdoctoral researcher at the Institute Molecular Clinical Ophthalmology Basel, presented a sensor that attaches to a retina that could help restore visual function in vision-impaired humans.
The sensor makes cells sensitive to near-infrared light. The system achieves this by combining nanotechnology with optogenetics, a technique to control cell activity with light. Gold nanorods serve as antennas, converting near-infrared light into local heat. This heat then opens up an ion channel known as a TRP channel attached to the nanorods to drive photocurrents through the retina. When she tested the sensor in blind mice, the mice were able to perform simple behavioral tasks. She aims for her system to help those with age-related macular degeneration or retinitis pigmentosa, two leading causes of blindness worldwide.
Zhijie Chen, a postdoctoral researcher at Northwestern University, presented his work on a class of porous materials known as metal-organic frameworks (MOFs). These network-like structures can be made from a variety of tunable materials and are known for their large surface area.
Chen has developed several applications using MOFs. In one, he designed a highly porous MOF called NU-1500 for hydrogen storage. In another, he integrated a MOF onto fabric that breaks down deadly chemical weapons known as nerve agents. To do this, the MOF captures water from the air, and the water breaks down the nerve agents with the help of a zirconium catalyst in the MOF. The fabric is intended for military uniforms.
Carter received the Materials Theory Award for “advances in quantum mechanics theory with broad applications to materials and chemical sciences.” Endowed by Dr. Gwo-Ching Wang and Dr. Toh-Ming Lu.
Gogotsi received the MRS Medal for “contributions to advancing the understanding of processing, structure, and properties of two-dimensional carbides and nitrides (MXenes) for energy storage applications.” Endowed by Dr. Gwo-Ching Wang and Dr. Toh-Ming Lu.
Lopez (Kavli Foundation Early Career Lectureship in Materials Science) for significant novel contributions to materials science. The Kavli Foundation is dedicated to advancing science for the benefit of humanity, promoting public understanding of scientific research and supporting scientists and their work.
Sheehan (MRS Nelson “Buck” Robinson Science and Technology Award for Renewable Energy) for the development of novel sustainable solutions for the realization of renewable sources of energy. Endowed by Sophie Robinson in memory of her father, Nelson "Buck" Robinson.
Nelidova (MRS Postdoctoral Award) for “creating tunable nanogenetic near-infrared light sensors to restore vision.” Supported by the Jiang Family Foundation and MTI Corporation.
Chen (MRS Postdoctoral Award) for “his outstanding contributions to the fields of porous materials, nanochemistry, and supramolecular assembly.” Supported by the Jiang Family Foundation and MTI Corporation.
2021 MRS Postdoctoral Award winner Zhijie Chen of Northwestern University discusses his work in the fields of porous materials, nanochemistry and supramolecular assembly.