Encapsulating Gold Nanoclusters into Melamine–Formaldehyde\nPolymer Nanoparticles for Confinement Induced Enhanced Emission toward\nRatiometric Sensing and Light-Emitting Diode Fabrication

Low photoluminescence quantum yield\n(PLQY) has long been one of\nthe key issues that impedes the versatile applications of gold nanoclusters\n(AuNCs). In this work, melamine–formaldehyde polymer nanoparticles\nwere employed as carriers to encapsulate AuNCs (AuNCs-MF PNPs), which\ncan trigger the confinement induced enhanced emission (CIEE) effect,\nremarkably enhancing the PLQY more than 25 times from 1.46% (AuNCs)\nto 36.90% (AuNCs-MF PNPs) and improving the stability toward pH. By\nsimultaneously incorporating AuNCs-MF PNPs and CDs as sensing probes,\nratiometric fluorescence detection of H<sub>2</sub>S with improved\nsensitivity was achieved. To realize the on-site detection of H<sub>2</sub>S, a portable sensing platform based on a smartphone was constructed.\nConsidering the high PLQY of AuNCs-MF PNPs, a light-emitting device\n(LED) was fabricated based on AuNCs-MF PNPs with favorable characteristics.\nThis work not only provides a novel strategy for preparing AuNCs with\nhigh PLQY but also highlights their potential in fluorescence sensing\nand the field of intelligent luminescence.