Rutile TiO2 inverse opal with photonic bandgap in the UV-visible range

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 TiO2 opaline nanocomposites which exhibited very interesting optical properties with a photonic bandgap (PBG) in the infrared range. The TiO2 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 TiO2 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 degrees C) are discussed. (C) 2010 Elsevier Inc. All rights reserved.