Institute for Nanoscience and Engineering

Anderson, United States

Institute for Nanoscience and Engineering

Anderson, United States
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News Article | April 13, 2017
Site: www.rdmag.com

University of Arkansas researchers have discovered a simple and scalable method for turning graphene oxide into a non-flammable and paper-like graphene membrane that can be used in large-scale production. “Due to their mechanical strength and excellent charge and heat conductivities, graphene-based materials have generated enormous excitement,” said Ryan Tian, associate professor of inorganic chemistry in the J. William Fulbright College of Arts and Sciences. “But high flammability jeopardizes the material’s promise for large-scale manufacturing and wide applications.” This characteristic of graphene has been an obstacle to further development and commercialization. However, this new discovery  makes it possible to safely mass-produce graphene and graphene membranes to improve a host of products, from fuel cells to solar cells to supercapacitors and sensors. Tian has a provisional patent for this new discovery. Using metal ions with three or more positive charges, researchers in Tian’s laboratory bonded graphene-oxide flakes into a transparent membrane. This new form of carbon-polymer sheet is flexible, nontoxic and mechanically strong, in addition to being non-flammable. Further testing of the material suggested that crosslinking, or bonding, using transition metals and rare-earth metals, caused the graphene oxide to possess new semiconducting, magnetic and optical properties. For the past decade, scientists have focused on graphene, a two-dimensional material that is a single atom in thickness, because it is one of the strongest, lightest and most conductive materials known. For these reasons, graphene and similar two-dimensional materials hold great potential to substitute for traditional semiconductors. Graphene oxide is a common intermediate for graphene and graphene-derived materials made from graphite, which is a crystalline form of carbon. The research was conducted by Hulusi Turgut, doctoral student in the U of A microelectronics-photonics program and the Institute for Nanoscience and Engineering. Part of the material’s characterization was done by Fengjiao Yu and Wuzong Zhou at the University of St. Andrews in the United Kingdom. The researchers’ findings were published in The Journal of Physical Chemistry. This intellectual property is patented by the University of Arkansas.


News Article | April 13, 2017
Site: www.rdmag.com

University of Arkansas researchers have discovered a simple and scalable method for turning graphene oxide into a non-flammable and paper-like graphene membrane that can be used in large-scale production. “Due to their mechanical strength and excellent charge and heat conductivities, graphene-based materials have generated enormous excitement,” said Ryan Tian, associate professor of inorganic chemistry in the J. William Fulbright College of Arts and Sciences. “But high flammability jeopardizes the material’s promise for large-scale manufacturing and wide applications.” This characteristic of graphene has been an obstacle to further development and commercialization. However, this new discovery  makes it possible to safely mass-produce graphene and graphene membranes to improve a host of products, from fuel cells to solar cells to supercapacitors and sensors. Tian has a provisional patent for this new discovery. Using metal ions with three or more positive charges, researchers in Tian’s laboratory bonded graphene-oxide flakes into a transparent membrane. This new form of carbon-polymer sheet is flexible, nontoxic and mechanically strong, in addition to being non-flammable. Further testing of the material suggested that crosslinking, or bonding, using transition metals and rare-earth metals, caused the graphene oxide to possess new semiconducting, magnetic and optical properties. For the past decade, scientists have focused on graphene, a two-dimensional material that is a single atom in thickness, because it is one of the strongest, lightest and most conductive materials known. For these reasons, graphene and similar two-dimensional materials hold great potential to substitute for traditional semiconductors. Graphene oxide is a common intermediate for graphene and graphene-derived materials made from graphite, which is a crystalline form of carbon. The research was conducted by Hulusi Turgut, doctoral student in the U of A microelectronics-photonics program and the Institute for Nanoscience and Engineering. Part of the material’s characterization was done by Fengjiao Yu and Wuzong Zhou at the University of St. Andrews in the United Kingdom. The researchers’ findings were published in The Journal of Physical Chemistry. This intellectual property is patented by the University of Arkansas.


News Article | March 21, 2016
Site: www.cemag.us

An international group of physicists has discovered a phenomenon of large magnitude in an unexpected class of materials that can lead to a variety of devices used in optical systems. That phenomenon — the elasto-optic effect — characterizes the formation of a periodic variance of light refraction when an acoustic wave propagates in optical materials, says Yurong Yang, a research assistant professor at the University of Arkansas who led the research. “We found a significantly large elasto-optic effect in thin films made of materials called ferroelectrics,” Yang says, “which are usually considered for their changes in mechanical energy into electrical energy and vice versa, as well in multiferroelectric thin films, which are commonly investigated because of the possible control of their magnetic response by electric input, as well as of their electric response by magnetic input.” The research group published its findings in a paper in Physical Review Letters, the journal of the American Physical Society. A second paper describing the research was published in Nature Communications, an online journal published by the journal Nature. “Those discoveries of a large elasto-optic effect in ferroelectrics and multiferroelectrics therefore broaden the potential of these materials since they can now be put in use to also control their optical responses by elastic property,” says Laurent Bellaiche, Distinguished Professor of physics at the U of A, “which suggests exciting device opportunities arising from this overlooked coupling in these classes of materials.” Yang and Bellaiche, who holds the Twenty-First Century Endowed Professorship in Nanotechnology and Science Education, both conduct research in the Institute for Nanoscience and Engineering and physics department at the U of A. The researchers performed calculations on supercomputers at the Arkansas High Performance Computing Center and a U.S. Department of Defense supercomputing resource. The results published in Physical Review Letters were obtained through a collaborative effort with Zhigang Gui, a U of A physics graduate who is now a postdoctoral research associate at the University of Delaware; Lan Chen and X.K. Meng at Nanjing University in China, and Daniel Sando and Manuel Bibes at University of Paris-Sud in France. The results published in Nature Communications were obtained through a collaborative effort with Daniel Sando and Manuel Bibes and Cecile Carretero, Vincent Garcia, Stephane Fusil, and Agnes Barthelemy at the University of Paris-Sud; Eric Bousquet and Philippe Ghosez at the University of Liege in Belgium; and Daniel Dolfi of Thales Research and Technology in France. Source: University of Arkansas


Grant P.C.,University of Arkansas | Fan D.,University of Arkansas | Mosleh A.,University of Arkansas | Yu S.-Q.,University of Arkansas | And 6 more authors.
Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics | Year: 2014

The effect of rapid thermal annealing on the optical and structural properties of GaAsBi/GaAs quantum wells (QWs) is investigated. The photoluminescence (PL) spectra of the samples are measured at 80K and room temperature before and after rapid thermal annealing, to ascertain any improvement in the optical quality of the material. The impact of annealing temperature on QW interface quality, layer composition, and thicknesses are studied with x-ray diffraction. For a 60second annealing time, the low temperature peak PL intensity increases to a maximum of 1.8 times the original intensity at an annealing temperature of 500°C. Validating this optimum annealing temperature, the room temperature PL peak intensity is seen to increase by 2.2 times. The peak position exhibits a minor blueshift of 15meV throughout the 450-700°C temperature range, while annealing at 750°C produces a blue-shift on the order of 100meV, indicating out-diffusion of bismuth from the QW. Degradation of the QW interfaces with annealing temperatures above 550°C is observed. The composition and thickness of the QWs remained constant up to 700°C. Significant out-diffusion of bismuth and QW thinning are observed at an annealing temperature of 750°C. © 2014 American Vacuum Society.


Jang G.G.,University of Arkansas | Hawkridge M.E.,Institute for Nanoscience and Engineering | Roper D.K.,University of Arkansas
Journal of Materials Chemistry | Year: 2012

Morphological and physicochemical disposition of silver (Ag) during redox-driven self-assembly of metal films on silica surfaces under equilibrium hydraulic conditions has been examined in real time in a novel electroless (EL) metal deposition cell by transmission UV-vis (T-UV) spectroscopy. Optical features due to localized surface plasmon resonance, surface plasmon polaritons, and photoluminescence from Ag and gold (Au) nanoarchitectures such as particles, clusters, and films were attributed by correlating T-UV with time-resolved scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Silver that deposited onto tin-sensitized surfaces in thin films nucleated nanoparticles when exposed to reductant or broadband light. Kinetic changes in plasmon features suggested four previously unrecognized time-dependent physicochemical regimes occur during consecutive EL deposition of Ag and Au onto tin-sensitized silica surfaces: self-limiting Ag activation; transitory Ag nanoparticle formation; transitional Au-Ag alloy formation during galvanic replacement of Ag by Au; and uniform metal deposition under controlled hydraulic conditions. Growth mechanisms at the surface, interior, and interface of the resulting thin metal films inferred from real time T-UV spectra were characterized by depth profile XPS analysis. © 2012 The Royal Society of Chemistry.


PubMed | Institute for Nanoscience and Engineering and University of Arkansas
Type: Journal Article | Journal: Food chemistry | Year: 2015

Eggs rich in trans, trans conjugated linoleic acid (CLA) are significantly more viscous, have more phospholipids containing linoleic acid (LA), and more saturated triacylglycerol species than control eggs. However, the fatty acid (FA) composition of yolk plasma and granule fractions are unreported. Furthermore, there are no reports of mayonnaise rheological properties or emulsion stability by using CLA-rich eggs. Therefore, the objectives were (1) compare the FA composition of CLA-rich yolk granules and plasma, relative to standard control and LA-rich control yolks, (2) compare the rheological properties of mayonnaise prepared with CLA-rich eggs to control eggs and (3) compare the emulsion stability of CLA-yolk mayonnaise. CLA-rich eggs and soy control eggs were produced by adding 10% CLA-rich soy oil or 10% of control unmodified soy oil to the hens diet. The eggs were used in subsequent mayonnaise preparation. CLA-yolk mayonnaise was more viscous, had greater storage modulus, resisted thinning, and was a more stable emulsion, relative to mayonnaise prepared with control yolks or soy control yolks.

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