Abstract
Colloidal crystals of polyelectrolyte multilayer (PEM)‐coated polystyrene spheres are used as templates for the preparation of lithium niobate inverse opal films (see Figure). The PEM coating facilitated the formation of the inverse opals and by controlling the layer thickness via layer‐by‐layer assembly, inverse opals with tailored structural properties (pore size, wall thickness, and channel diameter) are prepared.