Fabrication of Color-Tunable\nGold Nanoclusters and\nTheir Application for Information Encryption

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