Thermal stability of mesoporous silica-coated gold nanorods with different aspect ratios

Eszter Gergely-Fülöp, Dániel Zámbó, András Deák

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The effect of different temperatures (up to 900 °C) on the morphology of mesoporous silica-coated gold nanorods was systematically investigated. Gold nanorods with different aspect ratios (AR ranging from 2.5 to 4.3) were coated with a 15 nm thick mesoporous silica shell. Silicon supported monolayers of the particles were annealed in the temperature range of 300e900 °C. The resulting changes in particle morphology were investigated using scanning electron microscopy and visible wavelength extinction spectroscopy. The silica coating generally improved the stability of the nanorods from ca. 250 °C by several hundreds degree Celsius. For nanorods with AR < 3 the shape and the aspect ratio change is only moderate up to 700 °C. At 900 °C these nanorods became spherical. For nanorods with AR>3, lower stability was found as the aspect ratio decrease was more significant and they transformed into spherical particles already at 700 °C. It was confirmed by investigating empty silica shells that the observed conformal change of the shell material when annealing core/shell particles is dictated by the deformation of the core particle. This also implies that a significant mechanical stress is exerted on the shell upon core deformation. In accordance with this, for the highest aspect ratio (AR ∼ 4) nanorod the shell breaks up at 900 °C and the gold cores were partially released and coalesced into large spherical particles.

Original languageEnglish
Pages (from-to)909-913
Number of pages5
JournalMaterials Chemistry and Physics
Volume148
Issue number3
DOIs
Publication statusPublished - 2014

Keywords

  • Annealing
  • Deformation
  • Optical materials
  • Optical properties

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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