Phase separation strategy to facilely form fluorescent [Ag]/[Ag] quantum clusters in boro-alumino-silicate multiphase glasses

By adjusting the content of ZnF 2 -SrF 2 /ZnO-SrO, a series of SiO 2 -Al 2 O 3 -B 2 O 3 -Na 2 O-ZnO/ZnF 2 -SrO/SrF 2 -Ag multiphase glasses was designed and prepared via a melt-quenching method. Under a phase separation strategy, negatively charged tetrahedrons ([BO 4 ] − , [ZnO 4 ] 2− , and [AlO 4 ] − ) can be generated to stabilize different silver species (Ag + ions; [Ag 2 ] 2+ pairs; [Ag m ] n + quantum clusters ([Ag m ] n + QCs)) in B 2 O 3 -rich and ZnO-Al 2 O 3 rich sub-phases. The B 2 O 3 -rich sub-phase has a high solubility for Ag + ions and [Ag m ] n + QCs. The fluoride-rich phase shows a good ability to extract Na + from the B 2 O 3 -rich sub-phase, significantly affects the solubility of Ag + in the B 2 O 3 -rich sub-phase, and eventually determines the aggregation from Ag + ions and Ag 0 atom to [Ag m ] n + QCs. The ZnO-Al 2 O 3 -rich or ZnO-SiO 2 -rich ( i.e. SiO 2 -rich in GZnOSrO) phase has a relatively high solubility for [Ag 2 ] 2+ pairs. The Ag + /[Ag 2 ] 2+ /[Ag m ] n + QC fluorescent centers were identified by spectroscopic analysis, where the fluorescence bands are located in the ultraviolet, green-white and orange spectral regions, respectively. The fluorescent quantum yield (QY) of the [Ag m ] n + QCs can be improved to 55.7%, and the combination of these three luminescent centers can achieve white light emission. Ag + , [Ag 2 ] 2+ and [Ag m ] n + are well partitioned and stabilized in different sub-phases of the glasses to achieve high fluorescence QYs.