Compartmentalization of gold nanoparticle clusters in hollow silica spheres and their assembly induced by an external electric field

Kanako Watanabe, Tom A.J. Welling, Sina Sadighikia, Haruyuki Ishii, Arnout Imhof, Marijn A. van Huis, Alfons van Blaaderen, Daisuke Nagao

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Assembly of plasmonic nanoparticle clusters having hotspots in a specific space is an effective way to efficiently utilize their plasmonic properties. In the assembly, however, bulk-like aggregates of the nanoparticles are readily formed by strong van der Waals forces, inducing a decrease of the properties. The present work proposes an advanced method to avoid aggregation of the clusters by encapsulating into a confined space of hollow silica interior. Hollow spheres incorporating gold nanoparticle clusters were synthesized by a surface-protected etching process. The observation of inner nanoparticles with liquid cell transmission electron microscopy experimentally proved that the nanoparticles moved as a cluster instead of as dispersed nanoparticles within the water-filled hollow compartment. The hollow spheres incorporating the nanoparticle clusters were assembled in the vicinity of electrodes by application of an external AC electric field, resulting in the enhancement of Raman intensities of probe molecules. The nanoparticle-cluster-containing hollow spheres were redispersed when the electric field was turned off, showing that the hollow silica spheres can act as a physical barrier to avoid the cluster aggregation. The Raman intensities were reversibly changed by switching the electric field on and off to control the assembled or dispersed states of the hollow spheres.

Original languageEnglish
Pages (from-to)202-210
Number of pages9
JournalJournal of Colloid And Interface Science
Publication statusPublished - 2020 Apr 15


  • Hollow particles
  • Nanoparticle clusters
  • Particle assembly
  • Plasmonic nanoparticles
  • Plasmonic properties
  • surface-enhanced Raman scattering

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry


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