Energy level diagram and kinetics of luminescence of Ag nanoclusters dispersed in a glass host

Abstract

A site-selective spectroscopy study of Ag nanoclusters dispersed in oxyfluoride glass hosts has been carried out. The nano- to millisecond, essentially non-exponential, luminescence kinetics of Ag nanoclusters has been detected in the spectral range from 450 to 1000 nm, when excited at discrete wavelengths in the range 250 to 450 nm. Based on these experimental observations, the energy level configuration coordinate diagram for the involved ground and excited singlet/triplet states of the Ag nanoclusters has been proposed and confirmed by the density functional theory (DFT). The sites for the Ag nanoclusters are argued to be multiple. The structure/geometry of the involved Ag nanoclusters has been suggested to involve spin-paired dimers Ag²⁺, or tetramers Ag₄²⁺, with a varying elongation/distortion along the tetramer diagonals.

Enhanced broadband near-infrared luminescence in Bi-doped glasses by co-doping with Ag

“…19 Emission at around 740 nm may be due to ML-Ag, such as Ag 4 2þ . 18 Single Ag-doped glass shows luminescence at around 440 nm originating from Ag 2 þ when excited by 375 nm. 19 By contrary, the luminescence related to these Ag species in Ag and Bi co-doped glass is much weaker.…”

UV-driven efficient white light generation by Ag nanoclusters dispersed in glass host

“…1(a) and 2(a-d) and also from direct structural measurements by transmission electron microscopy [5]. The emitting Ag nanoclusters have been argued to be mostly Ag-tetramers with different degrees of elongation along the tetramer diagonal, based on quantum chemistry calculations [8].…”

“…The luminescent Ag nanoclusters are argued to consist of 2-4 silver atoms [3], in particular, the luminescent Ag nanoclusters dispersed in the bulk oxyfluoride glass host have been shown to be the Ag-tetramers with different degree of elongation along the tetramer diagonal [8]. A broad distribution of Ag nanoclusters sizes and their surroundings may results in large spectral width of the luminescence of Ag nanoclusters [8][9][10].…”

Silver doping of glasses

“…Luminescence properties were in general much studied [43][44][45][46][47][48], and exploited for example for application in solar technologies [49] and rare earth-silver glasses [50][51][52].…”