Vikas Berry is a K-State assistant professor of chemical engineering who works with graphene, a carbon material only a single atom thick and discovered just five years ago. To functionalize graphene with gold -- thus controlling its electronics properties -- Berry and Kabeer Jasuja, a K-State doctoral student in chemical engineering, embedded gold on graphene.
To do this, the engineers placed the graphene oxide sheets in a gold ion solution that had a growth catalyst. Here, the atomically thick sheets swim and bathe in a pool of chemicals.
"Graphene-derivatives act like swimming molecular carpets when in solution and exhibit fascinating physiochemical behavior," Berry said. "If we change the surface functionality or the concentration, we can control their properties."
They found that rather than distributing itself evenly over graphene, the gold formed islands on the sheets' surfaces. They named these islands snowflake-shaped gold nanostars, or SFGNs.
"So we started exploring how these gold nanostars are formed," Berry said. "We found out that nanostars with no surface functionality are rather challenging to produce by other chemical processes. We can control the size of these nanostars and have characterized the mechanism of nucleation and growth of these nanostructures. It's similar to the mechanism that forms real snowflakes."
Berry said the presence of graphene is critical for the formation of the gold nanostars. "If graphene is absent, the gold would clump together and settle down as big chunks," he said. "But the graphene helps in stabilizing the gold. This makes the nanostars more useful for electronic applications."
In July, Jasuja and Berry published their work in the journal ACS-Nano.
The discovery of these gold "snowflakes" on graphene shows promise for biological devices as well as electronics. Berry is attaching DNA to these gold islands to make DNA sensors. He is joined by Nihar Mohanty, a doctoral student in chemical engineering, and undergraduate researcher Ashvin Nagaraja, a senior in electrical engineering. Nagaraja is a 2004 Manhattan High School graduate.
Berry said graphene-gold based DNA sensors will have enhanced sensitivity. Chemically reducing graphene oxide to obtain graphene requires harsh chemicals that destroy the DNA.
"Now we can use the harsh chemicals on graphene oxide imbedded with gold to obtain graphene with gold islands. Then we can use these gold islands to functionalize DNA."
Berry also is using graphene in conjunction with microwaves. He and Jasuja are "cooking" the graphene sheets as another way to produce particles on the material's surface.
Some of Berry's other graphene research involves using the modified graphene sheets to compartmentalize a coagulating solution, thus stabilizing it. His group has recently used hydrides to reduce graphene oxide to produce reduced graphene oxide in the matter of a few seconds. The graphene produced in this way can remain stable in the solution for several days. Further results will shortly appear in the journal Small.
Discovered only five years ago, graphene has captured the attention of a large number of researchers who are studying its exceptional electrical, mechanical and optical properties, Berry said. His research group is among the few studying the material's interfacial properties and biological applications.
"We're entering a new era," Berry said. "From the zero-dimensional or one-dimensional molecular or polymer solutions, we are now venturing into the two-dimensional graphene solutions, which have fascinating new properties."
Vikas Berry, 785-532-5519, firstname.lastname@example.org
Vikas Berry | Newswise Science News
Further reports about: > 24-Carat > 24-Carat Gold > DNA > Graphene Research > Graphene-derivatives > Magnetic Properties > Ornament > chemical engineering > chemical process > electrical properties > electronics applications > gold nanostars > golden discovery > graphene > graphene sheets > molecular carpets > snowflakes
Ultrathin device harvests electricity from human motion
24.07.2017 | Vanderbilt University
Stanford researchers develop a new type of soft, growing robot
21.07.2017 | Stanford University
Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers
Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...
Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.
At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
25.07.2017 | Physics and Astronomy
25.07.2017 | Earth Sciences
25.07.2017 | Life Sciences