Anomalous Fluorescence Enhancement from Double Heterostructure 3D Colloidal Photonic Crystals-A Multifunctional Fluorescence-Based Sensor Platform

摘要

Augmenting fluorescence intensity is of vital importance to the development of chemical andbiochemical sensing, imaging and miniature light sources. Here we report an unprecedentedfluorescence enhancement with a novel architecture of multilayer three-dimensional colloidalphotonic crystals self-assembled from polystyrene spheres. The new technique uses a doubleheterostructure, which comprises a top and a bottom layer with a periodicity overlapping theexcitation wavelength (E) of the emitters, and a middle layer with a periodicity matching thefluorescence wavelength (F) and a thickness that supports constructive interference for the excitationwavelength. This E-F-E double heterostructure displays direction-dependent light trapping for bothexcitation and fluorescence, coupling the modes of photonic crystal with multiple-beam interference.The E-F-E double heterostructure renders an additional 5-fold enhancement to the extraordinary FLamplification of Rhodamine B in monolithic E CPhCs, and 4.3-fold acceleration of emission dynamics.Such a self-assembled double heterostructue CPhCs may find significant applications in illumination,laser, chemical/biochemical sensing, and solar energy harvesting. We further demonstrate the multifunctionalityof the E-F-E double heterostructure CPhCs in Hg (II) sensing.