Synthesis and characterization of Ag/Au alloy and core(Ag)-shell(Au) nanoparticles

Edit Csapó, Albert Oszkó, Erika Varga, Ádám Juhász, Norbert Buzás, László Korösi, Andrea Majzik, Imre Dékány

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39 Citations (Scopus)

Abstract

Bimetallic silver-gold nanoparticles (NPs) with different structures were prepared. Namely, silver-gold alloy and core(Ag)-shell(Au) type nanoparticles were synthesized at various Ag/Au ratios using only sodium citrate as reductant without any stabilizers. The synthesized NPs were characterized by different structure analysis methods. The unique optical properties of these NPs were studied by UV-vis spectroscopy. For Ag/Au alloy NPs the λmax values are linearly tunable from ∼408nm to 525nm depending on the composition. The plasmon band of core-shell NPs can be shifted to higher wavelengths by depositing a gold shell with increasing thickness. The HRTEM images clearly confirm the two different structures of the NPs. We found that the size of alloy nanoparticles decrease from d ∼15nm to d ∼8nm with the increase in gold content. In contrast, core(Ag)-shell(Au) type NPs with progressively increasing size (d=13-16nm) along with separately formed smaller gold NPs were formed.

Original languageEnglish
Pages (from-to)281-287
Number of pages7
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume415
DOIs
Publication statusPublished - Jan 1 2012

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Keywords

  • Alloy
  • Core-shell
  • Silver-gold nanoparticles
  • Structural analysis

ASJC Scopus subject areas

  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

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