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Title: Spontaneous decoration of Au nanoparticles on micro-patterned reduced graphene oxide shaped by focused laser beam

We report a facile, two-step method for the micro-landscaping of Au nanoparticles(NPs) on reduced graphene oxide (rGO) film en route to micro-patterned Au(NPs)-rGO hybrid functional materials. This method employs a focused laser beam to first locally convert GO to rGO before immersing the micro-patterned GO-rGO film into HAuCl{sub 4} solution. The rGO micro-pattern, shaped by the focused laser beam, serves as nucleation sites for the reduction of Au ions. The reduction mechanism that governs the decoration of Au NPs on rGO films is akin to electroless deposition process. In this instance, surface charges that are formed during laser reduction of GO to rGO provide active nucleation sites for Au{sup 3+} ions to form Au NPs when HAuCl{sub 4} solution is introduced. The number density, the size, and size distribution of the Au NPs can thus be directly tuned and preferentially anchored onto the rGO micro-pattern by varying the incident laser power, the scanning speed of the laser, or the concentration of HAuCl{sub 4}. The resulting hybrid materials can be used as a substrate for Surface Enhanced Raman Spectroscopy (SERS). Using Rhodamine 6G as the test subject, we found an improvement of SERS enhancement over bare rGO of up to fourmore » times, depending on the size of the Au NPs.« less
Authors:
;  [1] ;  [2] ;  [1] ;  [3]
  1. Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)
  2. Graduate School of Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456 (Singapore)
  3. (Singapore)
Publication Date:
OSTI Identifier:
22413051
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CARBON OXIDES; CONCENTRATION RATIO; DEPOSITION; FILMS; GOLD; GOLD IONS; GRAPHENE; MATHEMATICAL SOLUTIONS; NANOPARTICLES; NUCLEATION; RAMAN SPECTROSCOPY; SUBSTRATES; SURFACES