Abstract
Barium titanate (BaTiO3, BTO) and barium strontium titanate ((Ba,Sr)TiO3, BSTO) inverse opal photonic crystals were synthesized by a process of self-assembly of polystyrene opal template in combination with electrophoretic deposition of crystalline nanoparticles from BTO and BSTO suspension. In this process, stable monodispersed suspension of BTO and BSTO nanoparticles was prepared by dispersing BTO and BSTO gel into a mixed solvent of 2-methoxyethanol and acethylacetone. Then the BTO and BSTO nanoparticles were infiltrated into the interstices of the opal template formed by monodisperse polystyrene microspheres by electrophoretic deposition, and then Polystyrene template was removed by calcining the specimen at a final temperature of 500oC. SEM images show that the Lead-free ferroelectric inverse opals possess a face-centered cubic (fcc) structure with center to center distant of the air spheres between 250~330 nm. photonic bandgaps in the visible range (500~580nm)are observed from reflection spectra of the samples. Such Lead-free ferroelectric inverse opals as photonic crystals should be of importance in device applications.
