2023 Von Hippel Award

Reshef Tenne, Weizmann Institute of Science

Inorganic Nanotubes: From WS₂ to "Misfit" Layered Compounds

Written by Rahul Rao

On Tuesday evening, MRS bestowed its Von Hippel Award upon Reshef Tenne of the Weizmann Institute of Science. The Von Hippel Award rewards transcending the boundaries of conventional disciplines. Tenne spoke about some of the research that earned him the award: nanotubes grown with an ever-increasing variety of 2D materials.

In the early 1990s, not long after scientists first fashioned 2D carbon into nanotubes, Tenne and colleagues did the same with tungsten disulfide (WS₂) and molybdenum disulfide (MoS₂), whose structures contain one metal atom layer sandwiched between two layers of sulfur atoms. This configuration leaves dangling bonds at the edge that, when the compound is folded, are ripe for zipping up into nanotubes. These nanotubes are metastable and easy to make; three decades later, Tenne’s laboratory can spin out tungsten sulfide nanotubes that are as long as 500 µm.

Further research revealed that these nanotubes have some curious properties. For one, WS₂ nanotubes are very flexible and strong, capable of straining 10-12% without snapping. For another, although WS₂ and MoS₂ are indirect-bandgap materials, folding them into nanotubes shrinks the gap’s width and makes it direct.

 

 

Tenne discussed a few applications: WS₂ nanotubes are useful for reinforcing polymers; strong MoS₂ nanoparticles have already been commercialized as a heavy-duty lubricant. More recently, some of Tenne’s collaborators at the Beijing Institute of Technology have harnessed WS₂’s electro-optical properties to create a rudimentary artificial vision system: By applying different biases to WS₂ nanotubes, researchers created a 4 × 4 pixel grid that can capture a picture and store it in memory.

MoS₂ and WS₂ are hardly the only inorganic compounds that can form nanotubes. Tenne’s work also focuses on so-called “misfit” layered compounds, which contain alternating layers of a transition metal dichalcogenide (such as tantalum disulfide) and a rock salt (such as lead sulfide or lanthanum sulfide). The titular “misfit” comes from the fact that the dichalcogenide’s atomic structure does not align with the rock salt’s. As a result, one type of layer tends to expand while the other type contracts, encouraging the material to fold.

Tenne and his colleagues have, in the past decade, been able to create all kinds of misfit-compound nanotubes. They are now focusing on these nanotubes’ properties, like their chemical selectivity, stability, and electrical conductivity. For instance, nanotubes created from tantalum disulfide and samarium sulfide show superperiodicity between zigzag and armchair lattices in their layers; they also elegantly transition into superconductors at low temperatures.

Tenne received the Von Hippel Award for “spearheading modern research on nano-2D materials through the discovery of nanotube- and fullerene-like inorganic layered compounds.”

The Von Hippel Award, the Materials Research Society's highest honor, recognizes those qualities most prized by materials scientists and engineers—brilliance and originality of intellect, combined with vision that transcends the boundaries of conventional scientific disciplines.

2023 David Turnbull Lectureship

Mark Asta, University of California, Berkeley, and Lawrence Berkeley National Laboratory

Concentrated Alloys: Order, Disorder, and the Vast Space in Between

Written by Elizabeth Wilson

Concentrated alloys – materials that contain several or more different atoms in similar proportions – were only a curiosity when they were hypothesized decades ago. Scientists began synthesizing them less than 20 years ago.

In the past decade, interest in these concentrated alloys has exploded. Mark Asta has been developing theories that illuminate and predict these materials' behaviors.

“What made field take off is that we started to learn as a community that these materials had very special properties not seen in simpler materials,” Asta said at the MRS meeting in Boston, where he received the David Turnbull Lectureship Award.

They have potential use as ceramics, catalysts, and in extreme environments. For example, CrCoNi at low temperatures has among highest fracture toughness ever observed. “It's just shocking this happens because it's such a simple material,” said Asta.

His research focuses on the crucial phenomenon of short-range order (SRO) that arises randomly in atomic clusters. Though these small spots of order in the disordered bulk material are on the scale of nanometers, their effects can be far reaching.

 

 

For example, in semiconductor alloys, changes in short range order can change bonds and have big effects on band structure and electronic properties of a material.

These effects are not always desirable. They can, for instance, interfere with processes that reduce alloy corrosion. If a substance begins to corrode an alloy, atoms can percolate through the alloy and form a protective film. But in these concentrated alloys, ordered groups of atoms can spring up, blocking the percolation and inhibiting the film formation.

Asta described molecular dynamics simulations of CrCoNi, which explained how the energies of atoms involved in SRO enhanced the strength of the alloy.

Machine learning and databases generated from high-throughput experiments will play roles in expanding scientists’ understanding of these new exciting materials, Asta said. “If we want to progress, we need more theory.”

Asta was awarded the David Turnbull Lectureship for “seminal contributions to theory, computational modeling, and education on the structural, thermodynamic, and kinetic properties of phases, surfaces, and interfaces of materials.” Read more about Asta’s research in a recent issue of MRS Bulletin.

The David Turnbull Lectureship recognizes the career contribution of a scientist to fundamental understanding of the science of materials through experimental and/or theoretical research. In the spirit of the life work of David Turnbull, writing and lecturing also can be factors in the selection process.

2023 Innovation in Materials Characterization Award

Franz Giessibl, University of Regensburg, Germany
Atomic Force Microscopy 3.0

Written by Sophia Chen

Franz Giessibl is the 2023 recipient of the Innovation in Materials Characterization Award. Over more than three decades, the physicist at University of Regensberg in Germany has worked to develop and popularize the technology known as the atomic force microscope (AFM), which has allowed materials scientists to characterize subatomic such as the shape of electron clouds. “As far as I know, it [has] the best spatial resolution of any microscopy,” Giessibl says.

But it took just about Giessibl’s entire career so far for the field to achieve subatomic resolution. He delivered a virtual presentation tracing the evolution of the technology. Giessibl began working on AFM as a graduate student at ETH Zürich under Nobel laureate Gerd Binnig, who won the prize for co-inventing the scanning tunneling microscope. (Giessibl chose atomic force microscopy over Binnig’s other two suggested research topics, gravitational waves or sequencing DNA using the scanning tunneling microscope. “What project would you have chosen?” he asked the audience.)

Binnig had co-invented the AFM in 1986, just prior to Giessibl joining his team. The microscope images a material by scanning the surface with an extremely fine tip on the end of a cantilever. Early models of the microscope used silicon as a cantilever material and could not achieve atomic resolution, Giessibl said. It also used a piezoresistive material that required significant electric current, and thus produced heat, to sense motion in the tip. This presented a technical challenge, as researchers were interested in studying materials in a cryogenic setting.

The field grew in the 1990s, with Seizo Morita of University of Osaka starting the International Conference on Non-contact Atomic Force Microscopy, which is still held today. Still, Giessibl noted that atomic force microscopes didn’t sell, with only about 80 sold worldwide at the time. During that time, he pivoted to management consulting at McKinsey in Germany to try to understand the business aspects.

During his time at McKinsey, Giessibl began to develop what is now the QPlus sensor, a new type of force sensor for the AFM. Instead of a silicon cantilever, the QPlus uses a quartz one. Instead of piezoresistive material, they use piezoelectric material, which doesn’t heat up as prior models. In addition, the QPlus sensor converts the surface of the material into a vibration.

In the early 2000s, more groups began to develop this new type of microscope with a stiffer probe. Giessibl noted that it was easier to convince scientists from the scanning electron microscopy field than from atomic force microscopy. In 2008, Giessibl and his colleagues measured the force it took to push a single atom. In 2009, Leo Gross of IBM and his team discovered that adding a carbon monoxide molecule of the tip improved the resolution.

At the end of the talk, Giessibl showed the progression in the AFM’s imaging capability with a series of photos from 1995 to 2015. There are now more than 400 atomic force microscopes with QPlus sensors worldwide, he said. He noted that the field has finally demonstrated subatomic imaging in 2015 and 2019, and that he is now working on achieving ultrafast time resolution with atomic force microscopy.

The Innovation in Materials Characterization Award has been endowed by Gwo-Ching Wang and Toh-Ming Lu.

Congratulations to the 2023 MRS Spring Meeting & Exhibit Best Poster Award Winners!

The following posters were selected by the Meeting Chairs on the basis of the poster’s technical content, appearance, graphic excellence, and presentation quality (not necessarily equally weighted).

Tuesday Poster winners are Sungjun Choi (EL03.04.07), Rand Kingsford (EL17.03.01), Laud Anim Adofo (EN04.03.01), Arit Patra (QM04.04.04), Tanvi Kaku (SB05.04.24), and Simok Lee (SF04.03.12).

 

Wednesday Poster winners are Sreya Paladugu (CH03.05.02), Yong-Jin Park (EL08.08.10), MinWoo Jeong (EL18.09.45), Jiwoo Kim (EL19.07.13), Jingxuan Ding (EN06.05.07), and Young Hyun Noh (SB06.07.02).

 

Thursday Poster winners are Junia Shelomi Solomon Shelomi Solomon Sathiaraj (EL04.09.07), Daesol Kong (EL08.12.06), Natpaphat Jarulertwathana (EL19.10.22), Kihyun Lee (MD02.07.02), Jinmin Kim (SB06.12.07), and Katerina Rose DeOlivares (SF05.10.11).

Virtual Poster winner is Seong-Yong Cho (EL17.10.06).

2023 MRS Spring Meeting & Exhibit: Science as Art Competition

Congratulations to our winners!

2023 MRS Spring Meeting & Exhibit - Graduate Student Awards

Congratulations to this year's students!

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, is presented to a GSA finalist who shows particular promise as a future teacher and mentor.

 

MRS Award Recipients – Lightning Talks and Panel Discussion

Written by Cullen Walsh

At this year’s MRS conference, five materials researchers who were named for prestigious MRS awards were invited to give flash talks about their research. This was followed by Q&A with the audience during a panel discussion.

George Malliaras, the Prince Philip Professor of Technology at the University of Cambridge, was awarded the MRS Mid-Career Researcher Award for his contributions to organic electronic materials. He discussed how his research group takes cells from a patient and reprograms them to treat diseases. Specifically, he highlighted his work on biohybrid implants that contain both electronics and tissue. Through this combination, he showed that we can both maintain the health of a system and sustainably interface with the local biology while also inducing and guiding tissue repair.

Anne Lynn Gillian-Daniel, the Director of Education and Outreach at the University of Wisconsin-Madison Materials Research Science and Engineering Center, received the MRS Impact Award. She discussed engaging public audiences with educational activities inspired by research being performed at her university. Gillian-Daniel’s goal is to create educational opportunities and content for people of all backgrounds and ages. She highlighted her current project, called Science Outreach at the Pantry, which involves engaging with people in the waiting area of a local food pantry and distributing science activity kits.

Luisa Whittaker-Brooks, an associate professor at the University of Utah, was awarded the Outstanding Early Career Investigator Award for her work on electronic transfer between organic-inorganic interfaces. In her flash talk, Whittaker-Brooks first discussed her work on improving the electrical properties of organic electronics. For instance, she showed that by bonding dopants to organic electronics we can prevent dopant aggregation. She also discussed her research into point defects in transition metal dichalcogenides and showed how we can tune the capacitance of these materials using the defect density.

Qi Qian, a postdoc at the University of California-Los Angeles, and Yeonsik Choi, a former postdoc at Northwestern University, both received the MRS Postdoctoral Award. Qian talked about her research into high-quality van der Waals heterojunctions and superlattices for use in quantum transport. Her research extends to systems beyond two-dimensional materials by exploring three-dimensional organic and inorganic systems that also experience van der Waals forces. She highlighted her work on creating high-quality van der Waals contacts for lead halide perovskites as well as her research into intercalating organic molecules between van der Waals layers to tune their electronic properties.

Choi talked about his research into transient electronics that can be integrated into the human body. Specifically, he discussed his research into temporary cardiac pacemakers. Current cardiac pacemakers require invasive connections between the device and the heart and risky removal surgery after use. In contrast, Choi wants to make pacemakers that are both wireless and transient, meaning they dissolve within the body after use. To achieve this, he designed a stimuli-responsive polymer-based device that can survive in a rat’s body for over a month then degrade without compromising the health of the patient. 

During the panel discussion, the researchers working on bioelectronics were asked what possible impact artificial intelligence could have on their technologies. Malliaras discussed how artificial intelligence could help them fine-tune the stimulation in their bioregenerative implants. The award recipients were also asked about the challenges they faced over the course of their careers. Whittaker-Brooks talked about her experience as a Fulbright scholar from Panama and how that shaped her career as a scientist, while Gillian-Daniel talked about her experience transitioning from being a PhD researcher to an education outreach specialist.

Suveen Mathaudhu of Colorado School of Mines, chair of the MRS Awards Committee, moderated the Lightning Talks.

2023 MRS Mid-Career Researcher Award Recipient, George Malliaras

 

MRS TV speaks with George Malliaras, recipient of the 2023 MRS Mid-Career Researcher Award, for outstanding contributions to the fundamentals and development of organic electronic materials and their application in biology and medicine.

2023 MRS Postdoctoral Award Recipient, Qi Quan

MRS TV speaks with Qi Qian, recipient of the 2023 MRS Postdoctoral Award, for pioneering research in developing and understanding van der Waals heterostructures and superlattices.

MRS 2023 Postdoctoral Award winner, Yeon Sik Choi of Northwestern University

MRS TV speaks with Yeon Sik Choi , recipient of the 2023 MRS Postdoctoral Award, for the development of transient biomedical implants designed to provide therapeutic function over a clinically relevant timeframe, reducing costs and risks associated with a surgical extraction.