Negative curvature dependent plasmonic coupling and local field enhancement of crescent silver nanostructure

In this contribution, novel luminescent gold nanoclusters were synthesized by utilizing bovine serum albumin as templates with a simple, rapid, and one-pot procedure. The as-prepared gold nanoclusters were highly dispersed in aqueous solution and emitted an intense red fluorescence under UV light (365?nm). They exhibited strong fluorescence and the maximum excitation and emission wavelengths were 480 and 613.5?nm. In addition, the bovine serum albumin-stabilized gold nanoclusters were successfully utilized as novel fluorescent probes for the detection of quercetin for the first time. It was found that the addition of quercetin induced the strong fluorescence intensity of the gold nanoclusters to decrease. The decrease in fluorescence intensity of the gold nanoclusters caused by quercetin allowed the sensitive detection of quercetin in the range of 8.9?×?10^?8?C1.8?×?10^?4?mol?L^?1. The detection limit for quercetin is 1.8?×?10^?8?mol?L^?1 at a signal-to-noise ratio of 3. The present sensor for quercetin detection possessed a low detection limit and wide linear range. In addition, the real samples were analyzed with satisfactory results.