Ternary Inverse Opal System for Convenient and Reversible Photonic Bandgap Tuning

Abstract

A ternary system, consisting of air, an air-core/dense-silica-shell core-shell particle, and liquids has been used to fabricate an inverse opal structure with low fill factor, high refractive index contrast, and reversible tuning capabilities of the bandgap spectral position. The original close-packed opal structure is a ternary self-assembled photonic crystal from monodisperse and spherical polystyrene-core/silica-shell colloidal particles with air as the void material. Calcination removed the polystyrene and converted the core-shell particles to hollow spheres with a dense shell. In a final step, liquid is infiltrated only in the voids between the hollow spheres, but does not penetrate in the shell. This allows facile and reversible tuning of the bandgap properties in an inverse opal structure.

Synthesis of γ-Fe2O3/SiO2/Au magnetic composites for immobilization of bovine serum albumin

“…(Figure 1(a)) appeared quite different to the thiolated particles ( Figure 1(b)). The γ-Fe 2 O 3 /SiO 2 composite showed a clear core (γ-Fe 2 O 3 )-shell (SiO 2 ) structure with a smooth surface, spherical shape and uniform size, consistent with previous observations [18]. However, after the γ-Fe 2 O 3 /SiO 2 composite was functionalized with 3-mercaptopropyltriethoxysilane by condensation, the surface of the γ-Fe 2 O 3 /SiO 2 composite became rough, indicating that the surface of the particles has been modified with 3-mercaptopropyl groups.…”

Tunable Colors in Opals and Inverse Opal Photonic Crystals

“…[ 34 ] After colloidal assembly and sintering, the hollow silica spheres formed an opal with interstitial spaces…”

Direct generation of linearly polarized single photons with a deterministic axis in quantum dots

“…Silica nanospheres (d≈180 nm, fabricated in our laboratory [34]) were dispersed in ethanol and deposited onto the sample by drop casting. The nanospheres act as the etch mask for the nanopillars.…”