Optical quality mesoporous alumina thin films

A robust method for the preparation of optical-quality mesoporous alumina thin films is presented, using evaporation induced self assembly of triblock copolymer surfactants. The use of lowly reactive aluminium chloride as a precursor and a tertiary alcohol as a novel chloride scavenger results in highly homogeneous and smooth films with consistent controllable thickness between 30 and 100nm. The films show very low refractive index and high transparency from UV to NIR regions, providing a new building block for solution processing of devices requiring low-κ materials.