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

Abstract

last decades in search of improvements in the luminescent properties of europium given its relevance for optical device applications [1][2][3][4][5][6][7][8][9][10][11][12][13]. Malta et al. [1] irst reported that an improved photoluminescence (PL) of Eu 3+ ions in glass containing Ag nanoparticles (NPs) occurred due to the surface plasmon resonance (SPR) of the silver particles.Other groups subsequently concluded similarly on the role of local-ield efects of plasmonic Ag particles amplifying Eu 3+ PL in glasses [2,3,5,10,11,13]. On the other hand, several other studies have added to the discussion with respect to the conditions and mechanisms by which Eu 3+ emission is enhanced by the presence of silver [4,[6][7][8][9]12]. Namely, ionic metal species have been argued to be at the origin of energy transfer processes leading to a sensitized Eu 3+ PL rather than the Ag NPs themselves. Moreover, the NPs have been reported to instead lead to an eicient PL quenching of the rare-earth ions [4, 6] through an energy transfer/deactivating efect recently referred to as the plasmonic diluent efect [14]. Hence, achieving the desired enhanced optical properties is not straightforward. Moreover, it requires signiicant research eforts towards understanding the fundamental interactions between europium ions and the diferent oxidation and aggregation states of silver.Silicate [1-3, 7, 9, 12], borate [8], tellurite [10,11], and germanate [5] glasses were often the object of investigation regarding the interaction between europium and silver species. However, phosphate-based glass hosts notable for their high metal solubility, low-melting character, relatively low glass transition temperature, and high thermal stability are promising materials in the ield of photonics [13,15]. In these, the addition of aluminium oxide as a less acid network former results in a strengthened glass network with improved chemical durability and thermo-mechanical stability [16][17][18]. In addition, co-doping with SnO is believed Abstract The optical properties of Eu 3+ -doped aluminophosphate glass containing a high concentration of Ag 2 O 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 Eu 3+ ions is realized for the meltquenched 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 Eu 3+ ions in situ at 420 nm unveils the plasmonic diluent efect manifested through the quenching of Eu 3+ luminescence. The decay times of the 5 D 0 emitting state in Eu 3+ ions in the melt-quenched and NP-doped glasses are measured and discussed.

Nanodiamond-induced modifications of Eu-doped phosphate glasses toward photonic applications: A synergistic physico-chemical approach

“…2) since 320 nm is resonant with exciting the 7 F 0 -5 H 4 transition in Eu 3+ . 17,25 Thus Eu 2+ /Eu 3+ co-doping facilitated by C ND introduction in the melt, yields tunable colored emission with color coordinates presented in the CIE diagram, Fig. 4 inset.…”

“…2(a) shows the optical transmission spectra obtained for the various glasses under consideration. The Eu glass exhibits the dip in the transmission spectrum around 393 nm due to 7 F 0 -5 L 6 transition of Eu 3+ ions, 16,17 while the host absorption edge characterizes the decreased transmission toward shorter wavelengths. 9 It is observed for the EuND1 glass that a decreased transmission developed around 320 nm while the glass appears to have the transmission edge shifted towards shorter wavelengths.…”

Broadband visible luminescence in tin fluorophosphate glasses with ultra-low glass transition temperature

“…It was reported that the two fold coordinated Sn in SiO 2 and borate glass shows two emission bands: a-band [singlet (S 1 )-singlet (S 0 )] and b-band [triplet (T 1 )-singlet (S 0 )] and the Sn in phosphate glass just shows an emission band [triplet (T 1 )-singlet (S 0 )]. [29][30][31] Based on the above facts, we put forward that the shorter wavelength emission band around 432 nm can be mainly attributed to the S 1 -S 0 transition and the longer wavelength emission band around 520 nm can be ascribed to the T 1 -S 0 transition. Compared with Sn 2+ -doped 60ZnO-40P 2 O 5 glass, 27,32 the broadband luminescence of the SSP0 glass is in the visible wavelength range, which could be a new light source.…”

Enhanced and tunable white light emission from Ag nanoclusters and Eu3+-co-doped CaBAl glasses

“…8,[24][25][26] The heat treated samples present an absorption band centered around 420 nm, which is attributed to the SPR associated with the metallic Ag NPs. 8,18,27,28 Top insets present the SPR absorption intensity at 420 nm as a function of HT time, which increases with longer HT times and a higher temperature for both glass compositions. Furthermore, the samples doped with higher europium concentrations exhibit a higher rate for the intensity increase in SPR absorption compared to samples with a lower europium content indicating a higher density of Ag NPs, which agrees with the behavior reported by Jiao et al 27 The results indicate the incorporation of Eu and Ag ions in the host as well as the HT process promotes the precipitation of metallic Ag NPs.…”

“…Other reports also ascribe the RE luminescence enhancement to the energy transfer process from intermediate Ag species (isolated Ag + or Ag NCs) to RE ions instead of SPR contribution. 8,[16][17][18][19] Thus, the actual interaction mechanism between Ag species and RE ions is a controversial and unclear question, which requires further signicant investigation.…”