Au/titania composite nanoparticle arrays with controlled size and spacing by organic-inorganic nanohybridization in thin film block copolymer templates

A simple approach to prepare arrays of Au/TiO₂ composite nanoparticles by using Au-loaded block copolymers as templates combined with a sol-gel process is described. The organic-inorganic hybrid films with closely packed inorganic nanodomains in organic matrix are produced by spin coating the mixtures of polystyrene-block-poly(ethylene oxide) (PS-b-PEO)/HAuCl₄ solution and sol-gel precursor solution. After removal of the organic matrix with deep UV irradiation, arrays of Au/TiO₂ composite nanoparticles with different compositions or particle sizes can be easily produced. Different photoluminescence (PL) emission spectra from an organic-inorganic hybrid film and arrays of Au/TiO₂ composite nanoparticles indicate that TiO ₂ and Au components exist as separate state in the initial hybrid film and form composite nanoparticles after the removal of the block copolymer matrix.