Fabrication of Color-Tunable Gold Nanoclusters and Their Application for Information Encryption

The unique luminescence properties of gold nanoclusters (AuNCs) have attracted intense research interest in multiple areas. However, most AuNCs exhibit only a single-color emission. Achieving color-tunable emission through single AuNCs is attractive but still challenging. Herein, a switchable fluorescence strategy was introduced by integrating an aggregation-caused quenching (ACQ)-type ligand into an aggregation-induced emission (AIE)-type nanocluster system. In the AIE/ACQ strategy, 4,6-diamino-2-pyrimidinethiol (DPT)-AuNCs with color-tunable emission were developed: in the dimethylformamide (DMF)/water system, the DPT-AuNCs were dissociated and blue fluorescence was obtained, whereas in the MeOH/water system, DPT-AuNCs aggregated and strong orange phosphorescence was obtained. The emission color from orange to blue could also be switched by adjusting the solvent composition. Based on this strategy, the color-tunable AuNCs system was further employed for dynamic information encryption.