Coupling of Nanoparticle Plasmons with Colloidal Photonic Crystals as a New Strategy to Efficiently Enhance Fluorescence

In this paper, we present a new strategy for efficiently enhancing fluorescence, based on the coupling of surface plasmons of metal particles with optical properties of colloidal photonic crystals. It is found that such coupling can effectively improve the near-field effect and induced plasmon effect of metal particles but also be favorable for the extraction of the emission, collectively leading to a further significant enhancement of metal-enhanced fluorescence. Finite-difference time-domain (FDTD) simulation proved the related enhancement mechanism for the designed hybrid system. As a proof of concept, an enhancement factor up to 260-fold has been experimentally achieved by using rhodamine B as test molecule, which greatly transcends those of two individual plasmonic and photonic components and is also much larger than the simple plus effects of the two components.