Silver fused conducting fiber formation of Au-Ag core-shell nanoparticles mediated by ascorbic acid

A. Murugadoss, Manoranjan Kar, Renu Pasricha, Arun Chattopadhyay

Research output: Contribution to journalArticle

Abstract

In this paper, we report the spontaneous formation of fibrous structures consisting of assemblies of Au-Ag core-shell nanoparticles (NPs) from a solution consisting of Au-Ag core-shell NPs and l-ascorbic acid (AA). AA acted both as the reducing agent for the generation of NPs and also as the mediator for the formation of fibers. The process of fiber formation involved three steps-reduction of HAuCl4 to Au NPs by AA, subsequent formation of Au-Ag core-shell NPs after addition of AgNO3, and spontaneous formation of fibers from the mixtures in water. It took typically about 30 days to form complete fibers that are of lengths of several hundred micrometers to millimeters, although nanofibers started forming from the first day of solution preparation. The width of each of these fibers was typically about 1-4 μm with length of each segment of fiber bundle, on the order of 40 μm. Formation of fibers was also observed in absence of AgNO3. These fibers consisted of Au NPs and polymer of AA degradation products and were not electrically conducting. Also, low concentrations of AgNO3 produced fibers with low electrical conductivity. However, it was observed that increase in the amount of AgNO3 leads to the formation of fibers that were electrically conducting with conductivity values in the range of metallic conductivity. Spectroscopic and electron microscopic investigations were carried out to establish the formation of fibers. The details of fiber formation mechanism under different conditions and electrical conductivities of the fibers are discussed in the article.

Original languageEnglish (US)
Pages (from-to)161-170
Number of pages10
JournalPlasmonics
Volume4
Issue number2
DOIs
StatePublished - Jun 2009

Keywords

  • Ascorbic acid
  • Core-shell
  • Fiber
  • Gold
  • Nanoparticles
  • Silver

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biochemistry

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