Stable spectral dip formation and multicolour changes of plasmonic gold nanoparticles on TiO2

Spectral dip formation at arbitrary wavelengths and the corresponding multicolour changes were achieved by using plasmonic Au nanoparticles on TiO2, based on plasmon-induced charge separation and a coordination effect of iodide ions. The dips were stable in air under white light, in marked contrast to the case of conventional Ag nanoparticles.