Synthesis and photonic band calculations of NCP face-centered cubic photonic crystals of TiO2 hollow spheres

With the help of self-assembly, thermal sintering, selective etching techniques and sol–gel process, the non-close packed (ncp) face-centered cubic (fcc) photonic crystals of titanium dioxide (TiO2) hollow spheres connected by TiO2 cylindrical tubes have been fabricated using silica template. The photonic bandgap calculations indicate that the ncp structure of TiO2 hollow spheres was easier to open the pseudogaps than close packed system at the lowest energy.

Graphical abstractDiagram showing the steps of fabrication the photonic crystals of TiO2 hollow spheres connected by cylindrical tubes. (a) SiO2 opal, (b) sintered (1010 °C), (c) after etching by HF acid solution, (d) coated with titania, (e) photonic crystals of TiO2 hollow spheres connected by cylindrical tubes.Figure optionsDownload full-size imageDownload as PowerPoint slide