Rutile TiO 2 inverse opal with photonic bandgap in the UV–visible range

Abstract

Highly organized rutile Titania inverse opal-based photonic crystals that exhibit reflective properties in the UV–Visible range have been constructed. A self-assembly method was employed to infiltrate the interstitial space of a highly organized polymeric opal with a titania alkoxide precursor under well controlled conditions. Further hydrolysis and drying steps led to the formation of polystyrene spheres/amorphous TiO 2 opaline nanocomposites which exhibited very interesting optical properties with a photonic bandgap (PBG) in the infrared range. The TiO 2 inverted opal was subsequently obtained by the removal of the template either by chemical dissolution or calcination. The latter method was shown to yield samples of high quality and the influence of the calcination temperature on photonic crystal properties was studied by XRD, FESEM, EDX and Reflectance measurements. The highly organized, dense and thermally stable TiO 2 inverse opal obtained through calcination shows low defect density and a sharp reflection of incident UV–Vis–NIR light at around 380 nm and is then expected to possess a complete photonic bandgap due to the highly refringent dense rutile phase and the controlled and small lattice parameters of the crystal. The crystalline phase, the structural properties and the excellent thermal stability of the material (up to 1000 °C) are discussed.