Layer-by-layer self-assembly of dye–polyoxometalate multilayer composite films and their fluorescent properties

Abstract The layer-by-layer (LbL) self-assembly technique was successfully applied to the fabrication of dye–polyoxometalate multilayer composite films consisting of two dye molecules Rhodamine B (RB) and Rhodamine 6G (R6G) and a Keggin-type polyoxometalate [α-SiW 12 O 40 ] 4− (α-SiW 12 ). The composite films were characterized by UV-vis spectroscopy, scanning electron microscopy (SEM), and fluorescence spectroscopy. UV-vis spectra show that the characteristic absorbance values of the multilayer films increase almost linearly with the number of dye/α-SiW 12 bilayers, suggesting that the deposition process is regular and highly reproducible from layer to layer. SEM micrographs indicate that the film surface is a little rough with some individual granular domains. In addition, the fluorescent properties of these composite films were also investigated by fluorescence spectroscopy.