Reduction of non-radiative decay rates in boro-tellurite glass via silver nanoparticles assisted surface plasmon impingement: Judd Ofelt analysis

We report an enhancement in the absorption and emission cross-section of erbium ions (Er3+) inside zinc-boro-tellurite glass due to the impingement of silver (Ag) nanoparticles (NPs) into the host matrix. The impacts of varying Ag NPs concentration on the spectroscopic, structural, and thermal properties of such glass samples are evaluated. Synthesized glass samples are characterized using imaging and spectroscopic tools. XRD spectra confirmed the amorphous nature of glass samples and EDX spectra detected appropriate elements present in the glass including Ag. TEM micrographs revealed the distribution of Ag NPs with average size ~8.4 nm. FTIR spectra exhibited the fundamental stretching vibrations modes of glass network. Two surface plasmon resonance (SPR) peaks of Ag are divulged at 550 and 580 nm. Bonding parameters displayed the ionic nature of the Er−O metal-ligand linkages. Judd-Ofelt analysis is performed to calculate the radiative transition probability, stimulated emission cross-section, radiative lifetime and branching ratio for the excited levels of Er3+ ions in the prepared glass system. Intensity parameters and quality factors are calculated. Silver NPs impingement is found to augment the luminescence intensity by a factor as much as 3.32 times than the glass without NPs. The decay curves for the 4S3/2 level of Er3+ ion are recorded under 476 nm excitations, where the emission at 550 nm is registered. The lifetime is elongated from 6.36 μs to 9.07 μs with increasing silver NPs concentration from 0.0 to 0.9 mol%. Present glass compositions are established to be promising for the development of photonic devices

Impact of annealing time on silver nanoparticles growth assisted spectral features of erbium-zinc-boro-tellurite glass

Modifying the optical response of rare earth doped inorganic glasses by embedding nanoparticles is a never-ending quest. Accurate size and shape control of metal NPs inside the glass matrix through precise heat treatment (annealing) is challenging. We report for the first time, the effects of annealing time on the optical properties of the Er3+-doped zinc-boro-tellurite glasses containing silver NPs. Glasses are prepared using melt-quenching method where the growth of NPs is tuned by varying heat treatment duration. Modifications in physical, optical, and structural parameters are ascribed to the alteration of non-bridging oxygen due to HT. Shrinkage of NPs sizes from 12.8 to 6.6 nm for annealing time beyond 6 hr at 410 °C is ascribed to their diffusion limited growth. Surface plasmon resonance bands at 550 and 580 nm revealed red shift. The intensity parameters related to the radiative transitions within 4fn configuration of Er3+ ion are determined and analyzed using Judd-Ofelt theory. The room temperature emission spectra under 476 nm excitation exhibited three peaks centered at 536, 550 and 630 nm corresponding to the transitions from 2H11/2, 4S3/2 and 4F9/2 excited states to 4I15/2 ground state. Luminescence intensity enhancement (by a factor as much as 4.52) is majorly attributed to the local field effect of Ag NPs and quenching is due to the energy transfer from NPs to Er3+. Present glass compositions are demonstrated to be promising for the development of photonic devices

Tuning surface plasmon in erbium-boro-tellurite nanoglass via thermal annealing

The demand for tunable surface plasmon (SP) of embedded metal nanoparticles (NPs) in rare earth doped inorganic lasing glasses is ever-growing. Following melt quenching method Er3+ doped zinc-boro-tellurite glasses containing silver (Ag) NPs are prepared. Glasses are heat treated (thermally annealed) at varying temperatures and time duration to alter the NPs morphology which generates SP. The annealing assisted SP resonance mediated modification in spectral features is discerned. Samples heat treatment at 410°C for 6 hrs duration ensures the reduction of Ag+ ions to Ag° NPs. Thermally annealed glasses are characterized via XRD, UV–Vis-IR absorption, photoluminescence spectroscopy, and TEM imaging. XRD spectra confirm the amorphous nature of the glass and TEM image reveals the existence of homogeneously distributed spherically shaped silver NPs of average diameter ~4.5 nm. NPs are found to grow with the increase of both annealing time and temperature. The UV–Vis spectra exhibit seven absorption bands corresponding to 4f–4f transitions of Er3+ ions in the wavelength range of 500-650 nm. The localized SPR band is evidenced at 550 and 580 nm. Heat treatment causes a red shift of the plasmon peaks ascribed to the alteration in glass refractive index. Furthermore, the glass sample annealed for 6 hrs displays maximum enhancement in the emission intensity corresponding to the peaks centered at 536 (2H11/2→4I15/2), 550 (4S3/2→4I15/2) and 632 nm (4F9/2→4I15/2). This enhancement is primarily attributed to the local field effect of the silver NPs. Admirable features of the results suggest that our systematic method for heat treatment in tuning NPs size assisted SPR may contribute towards the development of functional glass

Spectroscopic properties of Sm3+ doped sodium-tellurite glasses: Judd-Ofelt analysis

Modifying the optical response of rare earth doped inorganic glasses for diverse optical applications is the current challenge in materials science and technology. We report the enhancement of the visible emissions of the Sm3+ ions doped sodium-tellurite (TNS) glasses. The impacts of varying Sm3+ ions concentration on the spectroscopic properties of such glass samples are evaluated. Synthesized glass samples are characterized via emission and absorption measurements. The UV–Vis–NIR absorption spectra revealed nine absorption peaks which are assigned to the transitions from the ground level (6H5/2) to 6P3/2, 4I11/2, 6F11/2, 6F9/2, 6F7/2, 6F5/2, 6F3/2, 6H15/2 and 6F1/2 excited energy levels of Sm3+ ions. Emission spectra of the prepared glass under 404 nm excitation wavelength consisted of four bands centered at 561 nm, 598 nm, 643 nm and 704 nm which are originated from 4G5/2→6HJ (J = 5/2, 7/2, 9/2 and 11/2) transitions. The experimental oscillator strengths, fexp are calculated from the area under absorption bands. Using Judd-Ofelt theory and fit process of least square, the phenomenological intensity parameters Ωλ (λ = 2, 4, 6) are obtained. In order to evaluate potential applications of Sm3+ ions in telluride glasses, the spectroscopic parameters: radiative transition probability AR, branching ratio BR, radiative life time τr and stimulated emission cross section σλ for each band are calculated. These glass compositions could be a potential candidate for lasers

Spectroscopic investigations of near-infrared emission from Nd3+-doped zinc-phosphate glasses: Judd-Ofelt evaluation

Zinc-phosphate glasses doped with different concentrations of Nd 3+ ions have been prepared by the melt quenching technique and characterized the spectroscopic properties. The physical properties by means of density and molar volume are determined. The amorphous nature of the glasses has been confirmed by X–ray diffraction analysis. FTIR spectra exhibited the fundamental stretching vibrations modes of glass network. In order to study the spectroscopic properties of fabricated glasses, absorption and emission spectroscopy has been performed. Additionally, the spectroscopic properties of Nd 3+ ions were analyzed using J–O theory. UV–Vis–NIR absorption spectra of glass samples divulged twelve significant peaks. Considerable enhancement of Ω 2 values with increasing neodymium content indicated an improvement in the covalency and asymmetry of Nd 3+ ions environment. Under the excitation of 808 nm laser diode, two near-infrared emission bands at around 890 and 1060 nm from 4 F 3/2 → 4 I 9/2 and 4 I 11/2 radiative transitions respectively were observed in the Nd 3+ single doped glasses. The major intensity is observed for 1060 nm for such glass samples. Nd 3+ ions dopant is found to augment the luminescence intensity by a factor as much as 2.23 times as the concentration of Nd 3+ ions increase up to 1.5 mol%. The lifetimes of this level has been experimentally determined through decay profile studies. The developed glass possesses high fluorescence quantum efficiency (η = 96%). The results indicate that the prepared glass system could be a suitable candidate for using it as laser gain media around 1060 nm, solid-state lasers and fiber amplifiers

Physical, structural, and Raman spectroscopic traits of neodymium-doped lead Oxyfluoride zinc phosphate glass

Nd3+ with composition of (60 - x) P2O5 - 10ZnO - 30PbF2 - (x) Nd2O3 where (0.0 ≤ x ≤ 2.0 mol %) was prepared using a melt-quenching approach to the development of transparent glasses. These glasses have been confirmed to be an amorphous structure through XRD analysis. The glass density, molar volume and ionic packing density were obtained in the range of 3.978- 4.157 g cm-3, 41.949 - 41.073 cm3 mol-1 and 0.614-0.624, respectively. Using Fourier Transform Infrared (FTIR) and Raman Spectroscopy, the chemical functional groups and biomolecules of samples were characterised. The FTIR spectra revealed six main bands assigned to P-O, P-O-P, P=O, (PO3)2- and hydroxyl groups (O-H), while Raman shift detected five symmetric and asymmetric bands attributed to P-O-P bonds in Q1 units, (PO4)3- bonds in Q0 units, (PO3)2- bonds in Q1 units, (PO2)- bonds in Q2 units and P=O bonds in Q3 units. It is believed that the proposed oxyfluoride glasses may be useful and suitable applicant to lasing materials and sensors sensitivity

Structural, chemical and magnetic features of gold nanoshapes integrated-Er2O3-doped tellurite glass system prepared by a conventional melt-quenching technique

Rare earth ions-doped oxide glasses with improved traits are needed for sundry applications. Based on this fact, physiochemical and magnetic characteristics of Er3+ -doped lead–tellurite glasses embedded with gold nanoshapes (Au-NSPs) were customized via preparation and characterization. Glasses of composition 78.95TeO2–15PbO–5PbCl2–1Er2O3–0.05AuCl3 were made using conventional melt-quenching techniques at varying (1, 6, 16, and 24 h) heat treatment durations (HTDs) to optimize their morphology, structure, chemical, and magnetic properties. Structure analysis verified the amorphous nature of the as-quenched samples and the homogeneous distribution of Au-NSPs within a network matrix with an average diameter ranged from 1.32 to 7.12 nm. Significant chemical functional groups of the glasses were detected at 360 and 598 cm‒1, attributed to the number of non-bridging oxygen (NBO) in glass and the conversion of TeO4 tbp into TeO3 polyhedra through TeO3+1. The magnetic behavior of the glasses was due to the diffusion-limited growth of Au-NSPs as evidenced from the ESR and VSM results. Saturation magnetization and magnetic coercivity were in the range of 4.61 × 10–2 to 10.614 × 102 emu/g) and 1441.60 to 1992.20 Oe, respectively. The variations of g-factor, resonant magnetic field, and peak-to-peak line-width of the glasses were established to be promising for various functional applications especially for biomedical devices as antiviral screen protectors