Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Researchers use graphene quantum dots to detect humidity and pressure

Vikas Berry, William H. Honstead professor of chemical engineering, and his research team are using graphene quantum dots to improve electron tunneling-based sensing devices.
Vikas Berry, William H. Honstead professor of chemical engineering, and his research team are using graphene quantum dots to improve electron tunneling-based sensing devices.

Abstract:
The latest research from a Kansas State University chemical engineer may help improve humidity and pressure sensors, particularly those used in outer space.

Researchers use graphene quantum dots to detect humidity and pressure

Manhattan, KS | Posted on May 8th, 2013



Vikas Berry, William H. Honstead professor of chemical engineering, and his research team are using graphene quantum dots to improve sensing devices in a twofold project. The first part involves producing the graphene quantum dots, which are ultrasmall pieces of graphene. Graphene is a single-atom thick sheet of carbon atoms and has superior electrical, mechanical and optical properties. The second part of the project involves incorporating these quantum dots into electron-tunneling based sensing devices.

To create the graphene quantum dots, the researchers used nanoscale cutting of graphite to produce graphene nanoribbons. T.S. Sreeprasad, a postdoctoral researcher in Berry's group, chemically cleaved these ribbons into 100 nanometers lateral dimensions.

The scientists assembled the quantum dots into a network on a hydroscopic microfiber that was attached to electrodes on its two sides. They placed the assembled quantum dots less than a nanometer apart so they were not completely connected. The assembling of dots is similar to a corn on the cob structure -- the corn kernels are nanoscale quantum dots and the cob is the microfiber.

Several researchers -- including four 2012 alumni in chemical engineering: Augustus Graham, Alfredo A. Rodriguez, Jonathan Colston and Evgeniy Shishkin -- applied a potential across the fiber and controlled the distance between the quantum dots by adjusting the local humidity, which changes the current flowing through the dots.

"If you reduce the humidity around this device, the water held by this fiber is lost," Berry said. "As a result, the fiber shrinks and the graphenic components residing atop come close to one another in nanometer scale. This increases the electron transport from one dot to the next. Just by reading the currents one can tell the humidity in the environment."

Decreasing the distance between the graphene quantum dots by 0.35 nanometers increased the device's conductivity by 43-fold, Berry said. Furthermore, because air contains water, reducing air pressure decreased its water content and caused the graphene quantum dots to get closer together, which increased conductivity. Quantum mechanics suggests that electrons have a finite probability to tunnel from an electrode to a nonconnected electrode, Berry said. This probability is inversely and exponentially proportional to the tunneling distance, or the gap between the electrodes.

The research has numerous applications, particularly in improving sensors for humidity, pressure or temperature.

"These devices are unique because, unlike most humidity sensors, these are more responsive in vacuum," Berry said. "For example, these devices can be incorporated into space shuttles, where low humidity measurements are required. These sensors might also be able to detect trace amounts of water on Mars, which has 1/100th of the earth's atmospheric pressure. This is because the device measures humidity at a much higher resolution in vacuum."

While the heart of the device is the modulation of electron tunneling, the response of the device is through the polymer microfiber, Berry said. His team also is looking at changing the polymer to find other applications for this research.

"If you replace this polymer with a polymer that is responsive to other stimuli, you can make a different kind of sensor," Berry said. "I envision this project to have a broad impact on sensing."

The research is supported by Berry's five-year, $400,000 National Science Foundation CAREER award. The research results appear in a recent issue of the journal Nano Letters in an article titled "Electron-tunneling modulation in percolating-network of graphene quantum dots: fabrication, phenomenological understanding, and humidity/pressure sensing applications."

The research is dedicated to Vasanta Pallem, a postdoctoral researcher who was involved in the work and died in a recent apartment fire.

Berry's research team also is studying molecular machines interfaced with graphene. In this work, the researchers are able to mechanically actuate the molecules, which undergo a change in the electric field around them and influence the carrier density of the interfaced graphene. This work will appear in an upcoming issue of the journal Small in an article titled "Covalent functionalization of dipole-modulating molecules on trilayer graphene: an avenue for graphene-interfaced molecular machines."

The researchers have found that graphene responds sensitively to molecular motion. Phong Nguyen, a doctoral student in chemical engineering and lead author of the work, tethered actuating molecules on graphene and measured the device's response.

"The next phase of science beyond nanotechnology will be molecular technology," Berry said. "We are working on developing routes to incorporate molecular machines into devices."

Other Kansas State University researchers involved include: Sreeprasad; Kabeer Jasuja, 2011 doctoral graduate in chemical engineering; Nihar Mohanty, 2011 doctoral graduate in chemical engineering; Myles Ikenberry, doctoral student in chemical engineering, Manhattan; and Keith Hohn, professor of chemical engineering. Other researchers include Junwen Li, graduate student at the University of Pennsylvania, and Vivek B. Shenoy professor of materials science and engineering at the University of Pennsylvania.

####

For more information, please click here

Contacts:
Vikas Berry

785-532-5519

Written by
Jennifer Tidball
785-532-0847

Copyright © Kansas State University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Vikas Berry's latest publication in Nano Letters can be viewed here:

Related News Press

News and information

Study reveals how herpes virus tricks the immune system February 5th, 2016

Hepatitis virus-like particles as potential cancer treatment February 5th, 2016

Organic crystals allow creating flexible electronic devices: The researchers from the Faculty of Physics of the Moscow State University have grown organic crystals that allow creating flexible electronic devices February 5th, 2016

Researchers discover new phase of boron nitride and a new way to create pure c-BN February 5th, 2016

Graphene/ Graphite

Nature Materials: Smallest lattice structure worldwide: 3-D lattice with glassy carbon struts and braces of less than 200 nm in diameter has higher specific strength than most solids February 3rd, 2016

Nanosheet growth technique could revolutionize nanomaterial production February 1st, 2016

Graphene shown to safely interact with neurons in the brain January 31st, 2016

Putting silicon 'sawdust' in a graphene cage boosts battery performance: Approach could remove major obstacles to increasing the capacity of lithium-ion batteries January 30th, 2016

Sensors

Scientists have put a high precision blood assay into a simple test strip: Researchers have developed a new biosensor test system based on magnetic nanoparticles February 3rd, 2016

Nanosheet growth technique could revolutionize nanomaterial production February 1st, 2016

New record in nanoelectronics at ultralow temperatures January 28th, 2016

NBC LEARN DEBUTS SIX-PART VIDEO SERIES, “NANOTECHNOLOGY: SUPER SMALL SCIENCE” Produced by NBC Learn in partnership with the National Science Foundation, and narrated by NBC News/MSNBC’s Kate Snow, series highlights leading research in nanotechnology January 25th, 2016

Discoveries

Study reveals how herpes virus tricks the immune system February 5th, 2016

Hepatitis virus-like particles as potential cancer treatment February 5th, 2016

Researchers discover new phase of boron nitride and a new way to create pure c-BN February 5th, 2016

Joint Efforts by Iranian, Malaysian Scientists Produce Antibacterial Coatings for Isolated Areas February 4th, 2016

Announcements

Study reveals how herpes virus tricks the immune system February 5th, 2016

Hepatitis virus-like particles as potential cancer treatment February 5th, 2016

Organic crystals allow creating flexible electronic devices: The researchers from the Faculty of Physics of the Moscow State University have grown organic crystals that allow creating flexible electronic devices February 5th, 2016

Researchers discover new phase of boron nitride and a new way to create pure c-BN February 5th, 2016

Aerospace/Space

Researchers develop completely new kind of polymer: Hybrid polymers could lead to new concepts in self-repairing materials, drug delivery and artificial muscles January 30th, 2016

Scientists build a neural network using plastic memristors: A group of Russian and Italian scientists have created a neural network based on polymeric memristors -- devices that can potentially be used to build fundamentally new computers January 28th, 2016

Deep Space Industries teams with UTIAS Space Flight Laboratory to demonstrate autonomous spacecraft maneuvering: SFL and DSI demonstrate enabling technology for low-cost asteroid missions and constellations January 25th, 2016

Graphene composite may keep wings ice-free: Rice University develops conductive material to heat surfaces, simplify ice removal January 25th, 2016

Quantum Dots/Rods

QD Vision Named to the 2015 Global Cleantech 100 Under the Radar List: Quantum Dot Leader Recognized for Clean Technology Innovation January 26th, 2016

Light-activated nanoparticles prove effective against antibiotic-resistant 'superbugs' January 19th, 2016

Nanoprobe development will enable scientists to uncover more DNA secrets January 17th, 2016

Researchers gauge quantum properties of nanotubes, essential for next-gen electronics: Imaging method allowed researchers to measure the nanotube quantum capacitance-a very unique property of an object from the nano-world January 8th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic