Fabrication of Cs2.5H0.5PW12O40 three-dimensional ordered film by colloidal crystal template

A three-dimensional ordered polyoxometalate periodic film was synthesized using dodecatungstophosphoric acid (H3PW12O40) and Cs2CO3 as precursors and colloidal crystals as templates by an inverse opal method. The samples were characterized by elemental analysis, XRD, IR spectra, UV–Vis diffuse reflectance spectra (DR–UV–Vis) and SEM techniques. This arrayed film constructed by pure cesium salt of dodecatungstophosphoric acid Cs2.5H0.5PW12O40 nanoparticles shows well-defined lamellar array with inverse opal structure, which exhibits a well-defined photonic band gap.