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This paper reports the first spectroscopic demonstration of photoluminescence ͑PL͒ owing to plasmon resonance energy transfer ͑PRET͒ from silver nanoparticles ͑NPs͒ to luminescent species in glass. Optical absorption and PL spectroscopy experiments performed on the melt-quenched silver-doped glass indicate the presence of single Ag + ions, Ag + -Ag + and Ag + -Ag 0 pairs, and Ag NPs. After thermal processing of the material, nonradiative energy transfer from the Ag + -Ag 0 luminescent centers to Ag NPs is observed by uniform suppression of band emission and the vanishing of the excitation band associated. Furthermore, evidence for PRET is observed after glass heat treatment by the appearance of a new excitation band near the surface plasmon resonance peak of Ag NPs at about 420 nm, when emission of silver pairs is monitored around 550 nm. In fact, excitation at 420 nm leads to a band emission centered around 530 nm indicating that the excitation of luminescent silver species indeed takes place via PRET. The luminescence is interpreted as arising from a Ag NP→ Ag + -Ag 0 → Ag + -Ag + energy transfer scheme.

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An aluminophosphate glass system containing silver and tin was prepared by the melt-quenching technique in which spherical silver nanoparticles (NPs) of different sizes were embedded upon heat treatment. Optical absorption was used in the assessment of particle growth and for particle size estimation yielding mean radii in the 10-40 nm range. Measurements in the UV region revealed absorption features indicative of the occurrence of silver ions and twofold-coordinated tin centers. Photoluminescence spectroscopy excited at 355 nm showed a broadband emission around 420 nm for the non-heat-treated glass, which shows a thermal quenching effect in temperature dependence measurements. Heat-treated glass shows a dip in the emission spectrum ascribed to absorption by NPs. The luminescence is attributed to single Ag + ions. The nature of the silver emitting states is discussed.