Phase separation strategy to facilely form fluorescent [Ag 2 ] 2+ /[Ag m ] n+ quantum clusters in boro-alumino-silicate multiphase glasses.

By adjusting the content of ZnF2 -SrF2 /ZnO-SrO, a series of SiO2 -Al2 O3 -B2 O3 -Na2 O-ZnO/ZnF2 -SrO/SrF2 -Ag multiphase glasses was designed and prepared via a melt-quenching method. Under a phase separation strategy, negatively charged tetrahedrons ([BO4 ]- , [ZnO4 ]2- , and [AlO4 ]- ) can be generated to stabilize different silver species (Ag+ ions; [Ag2 ]2+ pairs; [Agm ]n+ quantum clusters ([Agm ]n+ QCs)) in B2 O3 -rich and ZnO-Al2 O3 rich sub-phases. The B2 O3 -rich sub-phase has a high solubility for Ag+ ions and [Agm ]n+ QCs. The fluoride-rich phase shows a good ability to extract Na+ from the B2 O3 -rich sub-phase, significantly affects the solubility of Ag+ in the B2 O3 -rich sub-phase, and eventually determines the aggregation from Ag+ ions and Ag0 atom to [Agm ]n+ QCs. The ZnO-Al2 O3 -rich or ZnO-SiO2 -rich (i.e. SiO2 -rich in GZnOSrO) phase has a relatively high solubility for [Ag2 ]2+ pairs. The Ag+ /[Ag2 ]2+ /[Agm ]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 [Agm ]n+ QCs can be improved to 55.7%, and the combination of these three luminescent centers can achieve white light emission.