Optical Properties of Eu³⁺-Doped Aluminophosphate Glass with a High Concentration of Silver and Tin

The optical properties of Eu³⁺-doped aluminophosphate glass containing a high concentration of Ag₂O and SnO co-dopants (8 mol% of each) are reported. Glass preparation is carried out by melt-quenching, and a subsequent in situ monitored heat treatment (HT) is carried out for the reduction of ionic silver to Ag nanoparticles (NPs) via reducing agent tin(II). An enhanced ultraviolet broadband excitation range for Eu³⁺ ions is realized for the melt-quenched glass, likely due to the creation of molecule-like silver species such as Ag⁺–Ag⁺ dimers. The real-time optical monitoring of the glass during isothermal HT shows the steady development of the surface plasmon resonance peak of Ag NPs near 420 nm. Concurrently exciting Eu³⁺ ions in situ at 420 nm unveils the plasmonic diluent effect manifested through the quenching of Eu³⁺ luminescence. The decay times of the ⁵D₀ emitting state in Eu³⁺ ions in the melt-quenched and NP-doped glasses are measured and discussed.