Elucidating the Photoluminescence Origin of Silver Nanoclusters in Amorphous Matrices through Heavy-Atom Engineering

Silver (Ag) nanoclusters exhibit tunable dual emission integrating fluorescence and phosphorescence, yet in amorphous matrices blue fluorescence dominates, limiting phosphorescence and obscuring mechanisms of photoluminescence (PL). Here, halogen incorporation (Cl, Br, I) enhances heavy-atom effect, significantly increasing phosphorescence with a quantum yield of 27.54% through strengthened spin–orbit coupling and accelerated intersystem crossing. Iodide-modified glass achieves ultra-broadband emission (full width at half-maximum, fwhm = 223 nm), enabling its use as a single-component material for white-light-emitting diodes (WLEDs). The devices show stable chromaticity (CIE: 0.309, 0.352), high color rendering (Ra = 91.4), and correlated color temperature (CCT = 6552 K).