As electronic devices get smaller, the materials needed to create them get smaller as well. Nanoscience is the study of extremely small materials that find uses in energy storage, electronics, health and safety applications and more.
Now a team led by the U.S. Department of Energy’s (DOE) Lawrence Berkeley National Laboratory has developed a new self-assembly method to fabricate multilayered 2D nanosheets. A nanosheet is an extremely small, lasagna-like material made of ultrathin layers of polymers and nanoparticles.
These nanosheets have significantly reduced the number of defects compared with previous methods, which will extend the shelf life of some consumer electronics. Because the nanosheets synthesized by this new method are recyclable, this method could also enable a sustainable manufacturing approach that reduces the number of parts on an electronic device that need to be dumped into landfills.
“Our work overcomes a longstanding hurdle in nanoscience — scaling up nanomaterial synthesis into useful materials for manufacturing and commercial applications. It’s really exciting because this has been decades in the making.” — Ting Xu, Lawrence Berkeley National Laboratory
The team is the first to successfully develop a multipurpose, high-performance barrier material from self-assembling nanosheets. Researchers made use of the Advanced Photon Source (APS), a DOE Office of Science user facility at DOE’s Argonne National Laboratory. The breakthrough was reported in the journal Nature.
“Our work overcomes a longstanding hurdle in nanoscience — scaling up nanomaterial synthesis into useful materials for manufacturing and commercial applications,” said Berkeley Lab senior scientist Ting Xu, the principal investigator who led the study. “It’s really exciting because this has been decades in the making.”
One challenge in leveraging nanoscience to create functional materials is that many small pieces need to come together. This is so that the nanomaterial can grow large enough to be useful. While stacking nanosheets is one of the simplest ways to grow nanomaterials into a product, “stacking defects” — gaps between the nanosheets — are unavoidable when working with existing nanosheets.
“If you visualize building a 3D structure from thin, flat tiles, you’ll have layers up the height of the structure. But you’ll also have gaps throughout each layer wherever two tiles meet,” said first author Emma Vargo, a former graduate student researcher and now a postdoctoral scholar at Berkeley Lab. “It’s tempting to reduce the number of gaps by making the tiles bigger, but they become harder to work with,” Vargo said.
The new nanosheet material overcomes the problem of stacking defects by skipping the serial stacked sheet approach altogether. Instead, the team mixed blends of materials that are known to self-assemble into small particles. They used alternating layers of the component materials, suspended in a solvent.
Experiments at the Spallation Neutron Source, a DOE Office of Science user facility at DOE’s Oak Ridge National Laboratory, helped the researchers understand the early, coarse stages of the blends’ self-assembly. As the solvent evaporates, the small particles coalesce and spontaneously organize, coarsely templating layers. They then solidify into dense nanosheets. In this way, the ordered layers form simultaneously rather than being stacked one by one in a serial process. The small pieces only need to move short distances to get organized and close gaps. This avoids the problems of moving larger “tiles” and the inevitable gaps between them.
The researchers predicted that the complex blend used for the current study would have two ideal properties. They also expected that the new nanosheet system would be minimally affected by different surface chemistries. This, they reasoned, would allow the same blend to form a protective barrier on a variety of surfaces, such as the glass screen of an electronic device, or a polyester mask.
To test the performance of the material as a barrier coating in several different applications, the researchers enlisted the help of some of the nation’s best research facilities.
During experiments at the APS, the researchers studied how a mixture of polymers, organic small molecules and nanoparticles forms a film on the inner wall of a quartz capillary tube, when the solvent slowly evaporates in dry air.
“Thanks to the brilliant X-rays produced by the APS and the sophisticated X-ray detector stationed at Beamline 8-ID-I, we were able to map out how each component comes together across a wide range of length scales,” said Argonne scientist Qingteng Zhang, a co-author on the paper.
Now that they’ve successfully demonstrated how to easily synthesize a versatile functional material for various industrial applications from a single nanomaterial, the researchers plan to finetune the material’s recyclability. They’ll also add color tunability (it currently comes in blue) to its repertoire.
The APS is undergoing a comprehensive upgrade. When complete, the upgraded APS will enable probing of the self-assembly of the nanoparticles from nanoscopic to device scale, starting at the very beginning of the self-assembly process.
A version of this release was originally posted by Berkeley Lab.
About the Advanced Photon Source
The U. S. Department of Energy Office of Science’s Advanced Photon Source (APS) at Argonne National Laboratory is one of the world’s most productive X-ray light source facilities. The APS provides high-brightness X-ray beams to a diverse community of researchers in materials science, chemistry, condensed matter physics, the life and environmental sciences, and applied research. These X-rays are ideally suited for explorations of materials and biological structures; elemental distribution; chemical, magnetic, electronic states; and a wide range of technologically important engineering systems from batteries to fuel injector sprays, all of which are the foundations of our nation’s economic, technological, and physical well-being. Each year, more than 5,000 researchers use the APS to produce over 2,000 publications detailing impactful discoveries, and solve more vital biological protein structures than users of any other X-ray light source research facility. APS scientists and engineers innovate technology that is at the heart of advancing accelerator and light-source operations. This includes the insertion devices that produce extreme-brightness X-rays prized by researchers, lenses that focus the X-rays down to a few nanometers, instrumentation that maximizes the way the X-rays interact with samples being studied, and software that gathers and manages the massive quantity of data resulting from discovery research at the APS.
This research used resources of the Advanced Photon Source, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science.
The U.S. Department of Energy’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.