In Situ “Doping” Inverse Silica Opals
with Size-Controllable Gold Nanoparticles for Refractive Index Sensing
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Abstract
We report the fabrication of inverse
SiO<sub>2</sub> opals “doped”
with gold (i-Au-SiO<sub>2</sub>-o) nanoparticles (NPs) via a co-self-assembly
method combined with subsequent removal of polystyrene colloidal spheres
by calcination. The resulting i-Au-SiO<sub>2</sub>-o films demonstrate
long-range ordering with uniform distribution of ligand-free Au NPs.
The size of Au NPs can be tuned from 6 to 30 nm by varying the calcination
temperature. The as-prepared i-Au-SiO<sub>2</sub>-o films preserve
both localized surface plasmon resonance (LSPR) and Bragg diffraction
peaks simultaneously. Both LSPR and Bragg diffraction peaks are sensitive
to the refractive index changes of the surrounding mediuman
important feature for sensing applications. The method provides a
facile and versatile way to fabricate high-quality Au NP “doped”
photonic crystals for applications in sensing and others