Tunable photonic crystals-enhanced fluorescence by an assembly approach of polyelectrolyte interlayer

For the first time, we presented the tunable photonic crystals (PCs)-enhanced fluorescence by changing distance between fluorescent dyes and matched PCs. An assembly approach was employed to form the polyelectrolyte multilayer films on the PCs to adjust the distance between the fluorescent dyes and PCs. It was found the PCs-enhanced fluorescence behaviors exhibited the distance dependence. The layer number of polyelectrolytes between fluorescent dyes and PC films will have a considerable effect on the fluorescence properties of fluorescent dyes. The monolayer polyelectrolyte deposited on the PC surface can absorb more oppositely charged fluorophore molecules by an electrostatic interaction, resulting in an outstanding fluorescence enhancement compared to that on the PC film. With increasing the interlayers of polyelectrolytes between PCs and fluorophore molecules, the PC-enhanced fluorescence factors will decrease. Therefore, the distance between the fluorophores and matched PCs can be easily modulated to realize the tunable PC-enhanced fluorescence. The tunable PC-enhanced fluorescent material will have a promising application in the responsive fluorescence devices and sensors.