Fluorescence enhancement for noble metal nanoclusters

Noble metal nanoclusters have attracted great attentions in the area of fluorescence related applications due to their special properties such as low toxicity, excellent photostability and bio-compatibility. However, they still describe disadvantages for low quantum yield compared to quantum dots and organic dyes though the brightness of the fluorescence play an important role for the efficiency of the applications. Attentions have been attracted for exploring strategies to enhance the fluorescence based on the optical fundamentals through various protocols. Some methods have already been successfully proposed for obtaining relative highly fluorescent nanoclusters, which will potentially describe advantages for the application. In this review, we summarize the approach for enhancement of the fluorescence of the nanoclusters based on the modification of the properties, improvement of the synthesis process and optimization of the environment. The limitation and directions for future development of the fabrication of highly fluorescent metal nanoclusters are demonstrated.