Stacking of Ceramic Inverse Opals with Different Lattice Constants

Abstract

The feasibility of stacking of thin ceramic inverse opals with incommensurable periodicity constants was investigated. Inverse opals with photonic stopgaps in the infrared range were prepared by the vertical convective self‐assembly from aqueous suspensions of monodisperse polystyrene (PS) particles with the sizes of 476, 608, and 756 nm. The opal templates were infiltrated with TiO2 by a low‐temperature atomic layer deposition process using titanium isopropoxide and water as precursors. The second PS template could be deposited on top of the infiltrated opal layer after exposing the latter to the UV‐light, which rendered its surface hydrophilic. Finally, the sacrificial PS templates were removed by calcination at 500°C. It is shown that smoothness of the surface of the inverse opals is crucial for the photonic performance of the heterostructures. Two well‐defined stopgaps could be observed in the spectra of reflectance of the stacked inverse opals with improved surface morphology.