Carbon-Promoted <i>in Situ</i> Evolution of Cu Nanoclusters Influencing Eu<sup>3+</sup> Photoluminescence in Glass: Bidirectional Energy Transfer

J Inorg Organomet Polym

2016

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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.

Section: Inluence Of Thermal Processing On Glass Optical Absorption Acontrasting

confidence: 74%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Inluence Of Thermal Processing On Glass Optical Absorption Amentioning

confidence: 99%

See 2 more Smart Citations

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

J Inorg Organomet Polym

2016

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“…In the context of plasmonic materials, the addition of carbon as part of batch materials was recently demonstrated effective by the author for the controlled production of Cu nanocomposite glasses by melting and heat‐treatment (HT) processes . Similarly, the use of silicon powder was proposed for doping the glasses with Cu nanoparticles (NPs) .…”

Section: Introductionmentioning

confidence: 99%

Ag and Si Codoped Phosphate Glasses: Plasmonic Nanocomposites with Enhanced UV Transparency

2016

J. Am. Ceram. Soc.

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The use of silicon powder to produce plasmonic Ag nanocomposite phosphate glasses which also exhibit improved transparency in the ultraviolet (UV) is proposed. Ag2O/Si codoped glasses were prepared in a barium‐phosphate matrix by a simple melt‐quench method in ambient atmosphere. The as‐prepared glasses exhibit enhanced UV transparency, whereby the surface plasmon resonance of Ag nanoparticles (NPs) is manifested for the glasses with higher Ag2O contents. 31P nuclear magnetic resonance spectroscopy is consistent with the formation of P–O–Si bonds, thus suggesting their possible role on the improved UV light transmission. Consequently, a model was presented accounting for the influence of silicon on the polymerization of the phosphate network concomitant with the creation of highly reactive oxygen species. Further exploiting the proposed reactive species, a real‐time spectroscopic study of the plasmonic response of Ag NPs in Ag/Si codoped glass samples was carried out during an in situ thermal processing. The temperature dependence of the Ag particle precipitation was studied in the 400°C–430°C range, from which an Arrhenius‐type plot allowed for estimating the activation energy of the process at 3.42 (±0.38) eV. Ultimately, the vanishing of the luminescence ascribed to Ag+ ions was observed in a heat‐treated sample, consistent with the high reactivity acquired by the glass matrix. Silicon thus appears promising for producing UV transparent glasses for high‐performance optics and for the reduction of Ag+ ions to produce Ag nanocomposites valuable for photonic (nanoplasmonic) applications.

Temperature Dependent Spectroscopic Properties of Cu⁺ and Dy³⁺ Co‐Doped Phosphate Glass: Band Gap Analysis and Cu Nanocluster‐Enhanced Dy³⁺ Luminescence

2018

ChemPhysChem

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This paper reports on the effects of temperature on light absorption and emission in Cu + and Dy 3 + co-doped phosphate glass, which is of interest for photonic applications. First, the temperature dependence of the absorption edge of the glass in connection with Cu + ions absorption was assessed. A thermally-induced red shift attributed to Cu + ion-lattice interactions was observed and analyzed through optical band gap determinations in the context of indirect-allowed transitions. Application of the Varshni model for the dependence of the energy gaps with temperature allowed to estimate the 0 K energy gap at 2.87 (� 0.01) eV. Furthermore, Dy 3 + photoluminescence (PL) along with Cu nanoparticles (NPs) absorption was monitored in real-time during an isothermal treatment by the in situ concurrent PL and absorption microspectroscopy technique. Periods of enhancement and quenching of Dy 3 + emission linked to bidirectional energy transfer processes involving nonplasmonic Cu clusters and plasmonic Cu NPs were revealed. The formation of Cu NPs was promoted by tin(II) used as reductant. It is the first time to the author's knowledge that the 0 K energy gap is estimated for a highly Cu + -doped glass and that the enhancement of Dy 3 + PL by Cu clusters is exposed.[a] Dr.