Label-free detection of Pb2+ based on aggregation-induced emission enhancement of Au-nanoclusters

Abstract

Interestingly, the glutathione capped Au-nanoclusters presented here showed a unique optical performance compared with their homological AuNPs with larger size. The luminescence intensity of the AuNCs could be enhanced due to the formation of aggregates. The AuNCs were then employed as a visual probe for the detection of Pb²⁺ based on the aggregation-induced emission enhancement (AIEE) property of the AuNCs. When the luminous glutathione capped AuNCs probes encountered Pb²⁺ ions, they rapidly formed aggregates through GSH–Pb²⁺ interaction in 1 minute, resulting in an enhanced luminescence intensity. The enhanced luminescence intensities showed a linear dependence on the concentrations of Pb²⁺ with satisfactory selectivity towards 12 kinds of divalent metal ions. More importantly, the probe can also be used for on-site testing to inspect Pb²⁺ contamination by using a portable UV flashlight.