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

作者:Eftekhari Ehsan; Li Xiang; Kim Tak H; Gan Zongsong; Cole Ivan S; Zhao Dongyuan; Kielpinski Dave; Gu Min; Li Qin*
来源:Scientific Reports, 2015, 5(1): 14439.
DOI:10.1038/srep14439

摘要

Augmenting fluorescence intensity is of vital importance to the development of chemical and biochemical sensing, imaging and miniature light sources. Here we report an unprecedented fluorescence enhancement with a novel architecture of multilayer three-dimensional colloidal photonic crystals self-assembled from polystyrene spheres. The new technique uses a double heterostructure, which comprises a top and a bottom layer with a periodicity overlapping the excitation wavelength (E) of the emitters, and a middle layer with a periodicity matching the fluorescence wavelength (F) and a thickness that supports constructive interference for the excitation wavelength. This E-F-E double heterostructure displays direction-dependent light trapping for both excitation 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 FL amplification 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 multifunctionality of the E-F-E double heterostructure CPhCs in Hg (II) sensing.