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December 2021

November 2021

Web-based interactive materials science simulations for broader impacts in educations

Glad to have a chance to talk to Georgios Varnavides about his effort in developing tools for interactive materials science simulations using just-in-time (jit) compiler and observable platform. It is so cool that you can literally drag the particles and watch their deformations under the Lennard-Jones potential! Faster computation drastically changes how we can conduct our research, but it can also have an impact on how our next generations learn about materials sciences in school!

A demo tutorial from George:


DS01.03.01 and DS01.03.02: How computation makes a difference in zeolite synthesis

Nice to attend the talk from Daniel Schwalbe-Koda and Omar A. Santiago-Reyes about their work at Rafael Gómez-Bombarelli Group at MIT DMSE about combining high-throughput computation and machine learning for guiding the zeolite synthesis by selecting the best organic structure-directing agents (OSDAs). They specifically find the shape of OSDA is of particular importance in terms of zeolite synthesis by comparing to mined literature (with Elsa Olivetti Group) and experimental validation (with Yuriy Román Group), which has a high correlation with the binding affinity to zeolites. Therefore, they developed density-based interpolation descriptors for recommending the OSDA template and found alternative synthesis routes that are much cheaper. Using these descriptors also enables control of both zeolite synthesis and structure composition. Given the relatively high cost of using a re-parameterized force field to compute the binding affinity of OSDAs, Omar builds machine learning models to directly predict the binding affinity, enabling the exploration of billions of OSDA-zeolite pairs. Look forward to seeing what they will be doing in the future to leverage computational tools to aid materials synthesis and design!

Plenary Session Featuring The Fred Kavli Distinguished Lectureship in Materials Science

Plenary_HeadshotSir J. Fraser Stoddart, Northwestern University

Artificial Molecular Machines Going from Solution to Surfaces

Written by Don Monroe

Fraser Stoddart has been a pioneer in molecular machines, as recognized by sharing the 2016 Nobel Prize for Chemistry. A useful feature for these structures is the “mechanical bond,” such as that which holds together interlocking molecules, such as a ring-shaped molecule surrounding a dumbbell-shaped one. Among chemistry advances, “a new chemical bond is extremely rare,” he noted.

In his Kavli lecture, Stoddart focused on artificial molecular pumps that exploit this feature and add extra elements to achieve unidirectional motion. But he stressed that these pumps “don’t operate like the mechanical ones” that humans have used for millennia. “It’s a world of difference.”

In the nanomolecular pumps, the free-energy terrain is changed, allowing the molecules to jump around between different accessible states. “It’s all about kinetics,” rather than thermodynamics, he said. The kinetics of association and dissociation can be modulated by changing the charge state of radicals, for example by changing oxidizing or reducing conditions chemically, or electrochemically with an applied voltage.

Plenary_Speaking_800 Wide

Many of the structures Stoddart described use a “pumping cassette” that loads a charged ring-shaped radical onto a “collecting chain” where it is mechanically bound. This process can be repeated to load additional rings, with little increase in the free-energy cost. His research team has loaded as many as 80 rings onto a star polyethylene glycol, incorporating 344 positive charges.

Attaching pumping cassettes to both ends of a chain can double the loading. Stoddart noted that this technique can create a symmetrical loading of molecules, which could in principle be used to make palindromic polymers of the rotaxane ring molecules.

Moving away from solution chemistry, Stoddart illustrated the tethering of molecular pumps to a metalorganic-framework membrane. The result is what he termed “mechanisorption” to the membrane. Unlike the well-known physisorption and chemisorption, driven by van der Waals or chemical bonding, respectively, this process is intrinsically far from equilibrium, and is made possible by mechanical bonding.

Plenary_Stoddart_800 Wide

Stoddart also mentioned the potential for molecular nanotopology (formerly called chemical topology) to form various interlocking ring-like structures, including knots, belts, and Möbius strips. (The linear molecules employed for his molecular pumps do not satisfy this description.) “There are eight million knots, so we can keep chemists and materials scientists occupied for centuries,” he said, since only about a dozen have been made so far.

Although Stoddart admitted that he is “not an applications scientist,” he expressed the hope that the tools and techniques his group has developed could be helpful for battery technology and hydrogen storage as well as capture of CO2 and methane. He also expects that there will be huge opportunities in medical science, in view of the profound importance of biological molecular pumps.

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.

Tutorial EN01: Materials For Sustainable Electronics

WeidenkaffAnke Weidenkaff, Technical University of Darmstadt

Designing for Ultimately Sustainable Electronics

Written by Prachi Patel

The digital transformation of society has many advantages, but the downside is that we are creating large amounts of new types of waste. “That requires new solutions,” said Anke Weidenkaff during her talk on designing sustainable electronics from the ground up.

Weidenkaff, who is head of the Fraunhofer Research Institution for Materials Recycling and Resource Strategies IWKS, addressed the need for recycling electronic waste, and efforts at Fraunhofer to develop next-generation technologies that could lead to a closed loop for electronics materials.

Of the 53.6 megatons of e-waste generated globally in 2019, around 9 Mt was recycled, with half of it turned into reusable raw materials. So around 80 percent of global waste is not recycled, and this waste contains hazardous materials. At the same time, she said, there is a shortage of critical materials needed for batteries, fuel cells, electronics, and cars, among other things.

Moving from a linear to a circular economy for electronics would address environmental and materials supply issues. But electronic waste is difficult to recycle because it is more than just valuable metals. Weidenkaff called for a holistic approach to electronics recycling and a need to take circularity into account when designing and manufacturing products.

Weidenkaff and her colleagues have developed a digital design process for new materials that includes performance as well as sustainability as criteria. She described how they have used this modeling method to evaluate alternative catalyst materials for water electrolysis to produce green hydrogen, which today uses expensive platinum-based catalysts.

“We need to digitalize in the first hour of new material design and innovation,” she said. Digitalizing the synthesis and development process of new materials is key

because it gives products a “digital passport” so that when they reach end of life, data necessary for raw material utilization is already available.

She also highlighted the pressing need to recycle permanent magnets made from neodymium–iron–boron alloys that are used in electronics, electric car motors, wind turbine generators, and robotics. Less than 1 percent of Nd is recycled today.

She detailed the processes that the Fraunhofer team has developed to reprocess magnet alloys to make recycled magnets. One technique involves melting and quenching very rapidly to get flakes that have the necessary complex microstructure of the rare earth alloys. Another method involves a hydrogen treatment to give particles. The flakes and particles can be processed into new magnets.

The team has demonstrated the recycling of large scrap magnets from wind turbines. They are also using the recycled alloy powders for additive manufacturing of permanent magnets. During The Virtual Experience, on December 6, Weidenkaff’s colleague Sebastian Klemenz will present his work on developing recycled printing materials for additive manufacturing of functional materials for high-tech applications.

Real-Life Challenges and Opportunities in Sustainable Product Design Seminar

Alan Rae of NYS Center of Excellence in Materials Informatics discusses the Sustainable Product Design Seminar, in which attendees will earn how to incorporate sustainability principles into their research in a more comprehensive way while considering the real-world application of these principles to product design and manufacturing.



Symposium EQ20—Beyond Graphene 2D Materials—Synthesis, Properties and Device Applications

Joao Marcelo Lopes, Paul-Drude-institut für Festkörperelektronik

Selective-Area van der Waals Epitaxy of h-BN/Graphene Heterostructures via Defect-Engineering Using Focused He Ion Beam

Written by Andrew M. Fitzgerald

Combining unique layers of two-dimensional (2D) materials has great potential for creating ultrathin devices that have tunable chemical and electrical properties. Assembling these atomically thin devices using van der Waals epitaxy is a much better alternative than mechanical assembly, but van der Waals epitaxy often leads to uncontrolled nucleation leading to non-uniform growth of individual layers of these devices has proved itself to be a difficult challenge to overcome. Lopes’ research focuses on overcoming this challenge by using the focused ion beam of a helium ion microscope to intentionally introduce desired defects into these materials that are able to provide a mask-less, selective area growth method when assembling the individual layers of these ultrathin devices. Lopes’ work provides a way to overcome the non-uniform growth of individual 2D layers and allows for the scalable fabrication of these devices.

Symposium EN05—Emerging Energy and Materials Sciences in Halide Perovskites

Tsz Hin Edmund Chan, University of Exeter

Exploration of Hybrid Perovskite Superlattice for Efficient and Structurally Stable Stand-Alone Hybrid Solar PV Material

Written by Andrew M. Fitzgerald

Chan’s work focuses on a theoretical investigation into the electronic and structural properties of the materials making up hybrid perovskite solar cells. In particular, a superlattice comprised of two different perovskite materials, CH3NH3PBI3 (MAPI) and CH(NH2)2PBr3 (FAPB), is studied. Using a model of the system developed using both density functional theory and temperature dependent vibrational entropy correction, Chan presents results which show that varying the ratio of MAPI to FAPB can tune the bandgap and effective masses of this hybrid perovskite. Specifically, Chan shows that skewing the ratio in favor of FAPB can significantly decrease the bandgap. This work will help to further the research currently being done on perovskite solar cells by allowing experimental researchers to target hybrid perovskite materials for experimental synthesis and characterization that have been identified as holding the higher potential for greater solar cell efficiency.