Al₂O₃/TiO₂ inverse opals from electrosprayed self-assembled templates

The fabrication of high optical quality inverse opals is challenging, requiring large size, three-dimensional ordered layers of high dielectric constant ratio. In this article, alumina/TiO₂–air inverse opals with a 98.2% reflectivity peak at 798 nm having an area of 2 cm² and a thickness of 17 µm are achieved using a sacrificial self-assembled structure of large thickness, which was produced with minimum fabrication errors by means of an electrospray technique. Using alumina as the first supporting layer enables the deposition of TiO₂ at a higher temperature, therefore providing better optical quality.