Rice University theorists show flat boron form would depend on metal substrates
Rice University scientists have theoretically determined that the properties of atom-thick sheets of boron depend on where those atoms land.
Calculation of the atom-by-atom energies involved in creating a sheet of boron revealed that the metal substrate - the surface upon which two-dimensional materials are grown in a chemical vapor deposition (CVD) furnace - would make all the difference.
Theoretical physicist Boris Yakobson and his Rice colleagues found in previous work that CVD is probably the best way to make highly conductive 2-D boron and that gold or silver might be the best substrates.
But their new calculations show it may be possible to guide the formation of 2-D boron by tailoring boron-metal interactions. They discovered that copper, a common substrate in graphene growth, might be best to obtain flat boron, while other metals would guide the resulting material in their unique ways.
The Rice team's results appear today in the journal Angewandte Chemie.
"If you make 2-D boron on copper, you get something different than if you made it on gold or silver or nickel," said Zhuhua Zhang, a Rice postdoctoral researcher and lead author of the paper. "In fact, you'd get a different material with each of those substrates."
In chemical vapor deposition, heated gases deposit atoms on the substrate, where they ideally form a desired lattice. In graphene and boron nitride, atoms settle into flat hexagonal arrays regardless of the substrate. But boron, the researchers found, is the first known 2-D material that would vary its structure based on interactions with the substrate.
Perfectly flat boron would be a grid of triangles with occasional hexagons where atoms are missing. The researchers ran calculations on more than 300 boron-metal combinations. They found the pattern of atoms in a copper surface match up nicely with 2-D boron and the strength of their interactions would help keep the boron flat. A nickel substrate would work nearly as well, they found.
On gold and silver, they determined weak atomic interactions would allow the boron to buckle. In an extension, they theorized that naturally forming, 12-atom icosahedrons of boron would assemble into interconnected sheets on copper and nickel, if the boron supply were high enough.
One remaining downside to 2-D boron is that, unlike graphene, it will remain difficult to separate from its substrate, which is necessary for use in applications.
But that strong adhesion may have a side benefit. Further calculations suggested boron on gold or nickel may rival platinum as a catalyst for hydrogen evolution reactions in applications like fuel cells.
"In 2007 we predicted the possibility of pure boron fullerenes," Yakobson said. "Seven years later, the first one was observed in a laboratory. This time, with the enormous attention researchers are giving to 2-D materials, I'd hope some lab around the world will make 2-D boron much sooner."
Co-authors of the paper are graduate student Yang Yang and Rice postdoctoral researcher Guoying Gao. Yakobson is Rice's Karl F. Hasselmann Professor of Materials Science and NanoEngineering and a professor of chemistry.
The Department of Energy Office of Basic Energy Sciences supported the research.
Read the abstract at http://onlinelibrary.
This news release can be found online at http://news.
Follow Rice News and Media Relations via Twitter @RiceUNews
Yakobson Research Group: http://biygroup.
Rice Department of Materials Science and NanoEngineering: https:/
George R. Brown School of Engineering: http://engr.
Wiess School of Natural Sciences: http://naturalsciences.
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,888 undergraduates and 2,610 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for best quality of life and for lots of race/class interaction by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance.
David Ruth | EurekAlert!
New biomaterial could replace plastic laminates, greatly reduce pollution
21.09.2017 | Penn State
Stopping problem ice -- by cracking it
21.09.2017 | Norwegian University of Science and Technology
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy