Novel 'crumpling' of hybrid nanostructures increases SERS sensitivity

November 04, 2015

By "crumpling" to increase the surface area of graphene-gold nanostructures, researchers from the University of Illinois at Urbana-Champaign have improved the sensitivity of these materials, opening the door to novel opportunities in electronics and optical sensing applications.

"I believe that this work will benefit researchers in the area of surface plasmonics by providing a new strategy/design for enhancing the surface enhanced Raman spectroscopy (SERS) detection limit," explained SungWoo Nam, an assistant professor of mechanical science and engineering at Illinois. "This mechanical self-assembly strategy will enable a new class of 3D crumpled graphene?gold (Au) nanostructures. The enhanced limit of detection will allow biomedical and environment monitoring of important molecules at high sensitivity by SERS."

SERS substrates are used to analyze the composition of a mixture at the nanoscale for environmental analysis, pharmaceuticals, material sciences, art and archeological research, forensic science, drug detection, food quality analysis, and single cell detection. Using a combination of gold and silver nanoparticles and Raman-active dyes, SERS substrates also can target specific DNA and RNA sequences.

"This work demonstrates the unique capability of micro-to-nanoscale topographies of the crumpled graphene-Au nanoparticles--higher density, three-dimensional optically active materials--that are further enhanced by the formation of hot spots, bringing the nanoparticles closer," explained Juyoung Leem, a graduate student and first author of the study, "Mechanically Self-Assembled, Three-Dimensional Graphene?Gold Hybrid Nanostructures for Advanced Nanoplasmonic Sensors," published in Nano Letters. "We achieve a 3D crumpled graphene?Au hybrid structure by the delamination and buckling of graphene on a thermally activated, shrinking polymer substrate. This process enables precise control and optimization of the size and spacing of integrated Au nanoparticles on crumpled graphene for higher SERS enhancement."

According to Nam, the 3D crumpled graphene?Au nanostructure exhibits at least one order of magnitude higher SERS detection sensitivity than that of conventional, flat graphene?Au nanoparticles. The hybrid structure is further adapted to arbitrary curvilinear structures for advanced, in situ, nonconventional, nanoplasmonic sensing applications.

"One of the key advantages of our platform is its ability to shrink and adapt to complex 3D surfaces, a function that has not been previously demonstrated," Nam stated. An earlier study by Nam's research group was the first to demonstrate graphene integration onto a variety of different microstructured geometries, including pyramids, pillars, domes, inverted pyramids, and the 3D integration of gold nanoparticle/graphene hybrid structures.
-end-
In addition to Leem and Nam, the study's co-authors include post-doctoral researcher Pilgyu Kang and graduate student Michael Cai Wang in the Department of Mechanical Sciences and Engineering. Experiments were carried out in part in the Frederick Seitz Materials Research Laboratory, the Micro and Nano Technology Laboratory, and the Beckman Institute Imaging Technology Group at Illinois.

University of Illinois College of Engineering

Related Graphene Articles from Brightsurf:

How to stack graphene up to four layers
IBS research team reports a novel method to grow multi-layered, single-crystalline graphene with a selected stacking order in a wafer scale.

Graphene-Adsorbate van der Waals bonding memory inspires 'smart' graphene sensors
Electric field modulation of the graphene-adsorbate interaction induces unique van der Waals (vdW) bonding which were previously assumed to be randomized by thermal energy after the electric field is turned off.

Graphene: It is all about the toppings
The way graphene interacts with other materials depends on how these materials are brought into contact with the graphene.

Discovery of graphene switch
Researchers at Japan Advanced Institute of Science and Technology (JAIST) successfully developed the special in-situ transmission electron microscope technique to measure the current-voltage curve of graphene nanoribbon (GNR) with observing the edge structure and found that the electrical conductance of narrow GNRs with a zigzag edge structure abruptly increased above the critical bias voltage, indicating that which they are expected to be applied to switching devices, which are the smallest in the world.

New 'brick' for nanotechnology: Graphene Nanomesh
Researchers at Japan advanced institute of science and technology (JAIST) successfully fabricated suspended graphene nanomesh (GNM) by using the focused helium ion beam technology.

Flatter graphene, faster electrons
Scientists from the Swiss Nanoscience Institute and the Department of Physics at the University of Basel developed a technique to flatten corrugations in graphene layers.

Graphene Flagship publishes handbook of graphene manufacturing
The EU-funded research project Graphene Flagship has published a comprehensive guide explaining how to produce and process graphene and related materials (GRMs).

How to induce magnetism in graphene
Graphene, a two-dimensional structure made of carbon, is a material with excellent mechani-cal, electronic and optical properties.

Graphene: The more you bend it, the softer it gets
New research by engineers at the University of Illinois combines atomic-scale experimentation with computer modeling to determine how much energy it takes to bend multilayer graphene -- a question that has eluded scientists since graphene was first isolated.

How do you know it's perfect graphene?
Scientists at the US Department of Energy's Ames Laboratory have discovered an indicator that reliably demonstrates a sample's high quality, and it was one that was hiding in plain sight for decades.

Read More: Graphene News and Graphene Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.