Fabrication of Barium Strontium Titanate Inverse Opals by the Sol-Gel Process

Barium strontium titanate (BST) inverse opal photonic crystals (PCs) were fabricated by a process of self‐assembly of a polystyrene opal template in combination with infiltration of BST nanoparticles into the voids of a template. In this process, stable monodispersed BST nanoparticles were prepared by dispersing a BST gel into a mixed solvent of 2‐methoxyethanol and acetylacetone. Scanning electron microscopy images show that the inverse opals possess a face‐centered cubic lattice with a center‐to‐center distance of the air spheres of 270 nm. The X‐ray diffraction result reveals that a ferroelectric perovskite phase was obtained. A photonic bandgap in the visible range is observed from reflection spectra analysis and compared with the theoretical results.