Tags Posts tagged with "Center for Functional Nanomaterials"

Center for Functional Nanomaterials

Members of the quantum materials team, from left, Gregory Doerk, Jerzy Sadowski, Kevin Yager, Young Jae Shin and Aaron Stein. Photo from BNL

By Daniel Dunaief

Henry Ford revolutionized the way people manufactured cars through automation, speeding up the process, reducing waste and cutting costs.

Similarly, at Brookhaven National Laboratory, researchers like the newly hired Young Jae Shin, who is a staff scientist at the Center for Functional Nanomaterials, hopes to improve the process of automating the handling of thin flakes of material used in a next generation technology called quantum information science, or QIS.

Working with scientists at Harvard University and the Massachusetts Institute of Technology, Shin is looking for ways to handle these flakes, which are one atom thick, of two-dimensional layers from different materials. Stacked together, these flakes can help create structures with specific electronic, magnetic or optical properties that can be used as sensors, in communication, or encryption.

Young Jae Shin at Harvard University, where he was a post doctoral researcher. Photo from Y. Shin

“Researchers are building these kinds of customized structures manually now,” explained Kevin Yager, leader of the CFN Electronic Nanomaterials Group, in an email. “QPress [Quantum Material Press] will allow us to automate this.” At this point, QPress is just starting, but, if it works, it will “absolutely allow us to accelerate the study of these materials, allowing researchers to find optimal materials quickly,” Yager continued.

Theoretically, quantum computers overcome the limitations of other systems, Shin explained.

The flakes come from the exfoliation of thin structures taken from a bulk material. This is akin to a collection of leaves that fall around trees. According to Yager, the structures scientists hope to make would be akin to a collection of leaves from different trees, put together to make a new structure or material with specific properties. “The idea is for the robot to sift through the flakes, and identify the ‘best’ ones and to stack these together into the right structure. The ‘stacking’ will involve combining flakes of different materials,” he said.

The less desirable flakes typically are the wrong size, have tears, ripples or other defects and have contaminants. Groups of scientists are predicting the kinds of layered designs that will have desired properties.

Shin suggested that the CFN supports the needs of the end user community, as CFN is a “user-based facility.”

Physicists at Harvard and MIT plan to use the QPress to study unusual forms of superconductivity. By tapping into materials that conduct electricity without losing energy at lower temperatures, researchers may make progress in quantum computing, which could exceed the ability of the current state-of-the-art supercomputers.

Stacking the flakes can create new materials whose properties not only depend on the individual layers, but also on the angle between the stacks. Scientists can change one of these new structures from having metallic to having insulating properties, just by altering the relative angle of the atoms. The challenge, however, is that putting these fine layers together by hand takes time and generates errors which, BNL hopes, an automated approach can help reduce.

“Ultimately, we would like to develop a robot that delivers a stacked structure based on the 2-D flake sequences and crystal orientations that scientists select through a web interface” to a machine, Charles Black, the head of the Center for Functional Nanomaterials at BNL, explained in a recent BNL feature. “If successful, the QPress would enable scientists to spend their time and energy studying materials, rather than making them.”

Barring unforeseen delays, scientists anticipate that they will be able to build a machine that creates these flakes, catalogs them, stacks them and characterizes their properties within three years. These functions will be available online in stages, to allow the use of the QPress prior to its completion.

Each stage in the QPress process uses computer software to reduce the effort involved in generating and interpreting usable structures.

Minh Hoai Nguyen, an assistant professor in the Department of Computer Science at Stony Brook University and doctoral student Boyu Wang from the Computer Vision Lab at SBU are creating a flake cataloger, which will use image analysis software to scan and record the location of flakes and their properties.

“The flakes that scientists are interested in are thin and thus faint, so manual and visual inspection is a laborious and error-prone process,” Nguyen said in the BNL feature.

At BNL, Shin is one of three scientists the Upton-based facility is hiring as a part of this effort. They are also seeking robot or imaging process experts. Shin has “been in the CFN just a short while, but is already having an impact- — for instance, allowing us to handle classes of two-dimensional materials that we were not working with before,” Yager said.

The field of quantum information science is extremely competitive, with researchers from all over the world seeking ways to benefit from the properties of materials on such a small scale. The United States has been investing in this field to develop leadership science in this area.

The University of Tokyo has developed an automation system, but Shin explained that it is still not perfect.

Yager said that numerous unknown applications are “waiting to be discovered. Researchers are working hard on real quantum computers. Prototypes already exist but creating viable large-scale quantum computers is a major challenge.”

A resident of on-site housing at BNL, Shin was born in the United States and grew up in Korea. He is married to Hyo Jung Kim, who is studying violin at Boston University. 

As for the work Shin and others are doing, Yager suggested that the effort has generated considerable interest at the CFN.

“There is huge excitement at BNL about quantum research broadly and QPress in particular,” said Yager. Shin is “a big part of this — bringing new technical knowledge and new enthusiasm to this ambitious project.”

Eric Stach, group leader of Electron Microscopy at BNL and Special Assistant for Operando Experimentation for the Energy Sciences Directorate. Photo from BNL

In a carpool, one child might be the slowest to get ready, hunting for his second sneaker, putting the finishing touches on the previous night’s homework, or taming a gravity-defying patch of hair. For that group, the slowest child is the rate-limiting step, dictating when everyone arrives at school.

Similarly, chemical reactions have a rate-limiting step, in which the slower speed of one or more reactions dictates the speed and energy needed for a reaction. Scientists use catalysts to speed up those slower steps.

In the world of energy conversion, where experts turn biomass into alcohol, knowing exactly what happens with these catalysts at the atomic level, can be critical to improving the efficiency of the process. A better and more efficient catalyst can make a reaction more efficient and profitable.

That’s where Brookhaven National Laboratory’s Eric Stach enters the picture. The group leader of Electron Microscopy, Stach said there are several steps that are rate-limiting in converting biomass to ethanol.

By using the electron microscope at Center for Functional Nanomaterials, Stach can get a better structural understanding of how the catalysts work and find ways to make them even more efficient.

“If you could lower the energy cost” of some of the higher-energy steps, “the overall system becomes more efficient,” Stach said.

Studying catalysts as they are reacting, rather than in a static way, provides “tremendous progress that puts BNL and the Center for Functional Nanomaterials at the center” of an important emerging ability, said Emilio Mendez, the director of CFN. Looking at individual atoms that might provide insight into ways to improve reactions in energy conversion and energy storage is an example of a real impact Stach has had, Mendez said.

Stach works in a variety of areas, including Earth-abundant solar materials, and battery electrodes, all in an effort to see the structure of materials at an atomic scale.

“I literally take pictures of other people’s materials,” Stach said, although the pictures are of electrons rather than of light.

Stach, who has been working with electron microscopes for 23 years, gathers information from the 10-foot tall microscope, which has 25 primary lenses and numerous smaller lenses that help align the material under exploration.

His work enables him to see how electrons, which are tiny, negatively charged particles, bounce or scatter as they interact with atoms. These interactions reveal the structure of the test materials. When these electrons collide with a gold atom, they bounce strongly, but when they run into a lighter hydrogen or oxygen atom, the effect is smaller.

Since Stach arrived at BNL in 2010, he and his staff have enabled the number of users of the electron microscope facility to triple, estimated Mendez.

“The program has grown because of his leadership,” Mendez said. “He was instrumental in putting the group together and in enlarging the group. Thanks to him, directly or indirectly, the program has thrived.”

Lately, working with experts at the newly-opened National Synchrotron Light Source II, Stach, among other researchers, is looking in real time at changes in the atomic structure of materials like batteries.

In February, Stach was named Special Assistant for Operando Experimentation for the Energy Sciences Directorate.

“The idea is to look at materials while they are performing,” he said. Colleagues at the NSLS-II will shoot a beam of x-rays through the battery to “see where the failure points are,” he said. At the same time, Stach and his team will confirm and explore the atomic-scale structure of materials at Electron Microscopy.

Working with batteries, solar cells, and other materials suits Stach, who said he “likes to learn new things frequently.”

Residents of Setauket, Stach and his wife Dana Adamson, who works at North Shore Montessori School, have an 11-year old daughter, Gwyneth, and a nine year-old son, Augustus. The family routinely perambulates around Melville Park with their black lab, Lola.

In his work, Stach said he often has an idea of the structure of a material when he learns about its properties or composition, even before he uses the electron microscope. “The more interesting [moments] are when you get it wrong,” he said. “That’s what indicates something fundamentally new is going on, and that’s what’s exciting.”