Ezza Syuhada Sazali

Influence of europium ion on structural, mechanical and luminescence behavior of tellurite nanoglass

Understanding the mechanism of enhanced luminescence of rare earth doped glasses in the presence of nanocrystallites and growth kineics is fundamentally important for optical devices. Tellurite nanoglasses of composition (80-x) TeO2 − 5 Na2O − 15 MgO − (x) Eu2O3, over the concentration region of 0 to 2.5 mol% are prepared using conventional melt-quenching technique. The nanocrystalline particles are obtained by heating the as-cast glass at temperature 15−20°C above the glass crystallization temperature (Tc). The sizes of nanocrystallites are estimated from the X-Ray Diffraction (XRD) pattern using the Scherrer equation having average diameter ~68.7 nm. SEM studies revealed the nanocrystal glass morphology associated with the existence of crystalline phase. The glass density is determined by Precisa Densitometer and the hardness by the Vickers micro-hardness method. The density of tellurite nano-glass is found to be in the range of 5.2413 to 5.4933 g cm−3 while the Vickers microhardness varies from 2.77 to 2.93 GPa depending on the dopant concentration. The photoluminescence (PL) spectra exhibits five peaks around 568 nm, 600 nm, 628 nm, 664 nm and 712 nm assigned to 5D0 → 7F0, 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3 and 5D0 → 7F4 transitions respectively. Interestingly, the FWHM and the inverse quality factor of the heat-treated glass are found to decrease with increasing concentration of Eu3+ dopants. Our observation may contribute towards the development of solid state lasers.

Erbium concentration dependent absorbance in tellurite glass

Enhancing the optical absorption cross-section in topically important rare earth doped tellurite glasses is challenging for photonic devices. Controlled synthesis and detailed characterizations of the optical properties of these glasses are important for the optimization. The influence of varying concentration of Er3+ ions on the absorbance characteristics of lead tellurite glasses synthesized via melt-quenching technique are investigated. The UV-Vis absorption spectra exhibits six prominent peaks centered at 490, 526, 652, 800, 982 and 1520 nm ascribed to the transitions in erbium ion from the ground state to the excited states 4F7/2, 2H11/2, 4F9/2, 4I9/2, 2H11/2 and 4I13/2, respectively. The results are analyzed by means of optical band gap Eg and Urbach energy Eu. The values of the energy band gap are found decreased from 2.82 to 2.51 eV and the Urbach energy increased from 0.15 to 0.24 eV with the increase of the Er2O3 concentration from 0 to 1.5 mol%. The excellent absorbance of the prepared tellurit...

Effect of ZrF4 on the Physical and Absorption Properties of Magnesium Tellurite Glass

Tellurite glass containing zirconium fluoride (ZrF4) with composition of (90-x)TeO2-10MgO-(x)ZrF4,where 0.0 ≤ x ≤ 6.0 in mol% has successfully been prepared by melt quenching technique. X-Ray Diffraction (XRD) pattern verified the amorphous nature of the glass. In this study, the physical and optical properties were investigated in term of density and absorption properties by using Archimedes method and UV-Vis Spectroscopy. It was found that glass density decreases in the range of 4.842 – 4.995 g cm-3 with the increase of ZrF4 concentration. Meanwhile, the molar volume is increased in the range from 29.566 to 30.593 cm3/mol with increase of ZrF4. The absorption edge is found to shift toward a higher wavelength as the ZrF4 concentration is increased. On the other hand, the optical energy band gap shows the decrement from 2.573 to 2.212 eV for indirect transition and from 3.044 to 2.927 eV for direct transition with the addition of ZrF4 concentration while the Urbach energy, increases from 0.302 to 0.498 eV with the increase of ZrF4. All the results will be discussed with respect to the glass composition.

Gold Nanoparticles Embedded Erbium-Lead-Tellurite Glass: Bonding Parameters Evaluation

Au NPs contents dependent modifications in the absorption and bonding parameters are inspected. Glass systems with composition (79-y)TeO2 – 15PbO – 5PbCl2 – 1Er2O3 – (y)AuCl3 where 0.0 ≤ y ≤ 0.1 mol% are prepared and characterized using X-ray Diffraction (XRD). The absorption characteristics of the glass are observed using UV-Visible-NIR (UV-VIS-NIR) spectrophotometer. XRD spectra confirm the amorphous nature of all samples. UV-VIS-NIR spectra reveal seven absorption bands centered at about 490, 526, 551, 652, 800, 982 and 1520 nm originating from 4I15/2 to 4F7/2, 2H11/2, 4S3/2,4F9/2, 4I9/2, 4I11/2 and 4I13/2 transitions, respectively. The low value of indicated an increase in the covalency and the positive sign of for all glass systems indicates the bonding between the RE ions and the surrounding ligand is covalent in nature.

Absorption features and luminescence enhancement of tellurite glass embedded with metallic nanoparticles

This presentation provides a panoramic overview of the recent progress in nanoglass plasmonics, challenges, excitement, applied interests and the future promises. Enhanced optical properties of rare earth (RE) doped glasses for sundry applications are current challenges in materials science and technology. Nanoparticles (NPs) dispersed up-converted (UC) glasses seem to be the ideal candidates in terms of both efficiency and large area coverage provided the absorption cross-section be enhanced. The glasses containing gold NPs (AuNPs) and silver NPs (AgNPs) doped with optimum concentration of RE ions are of particular interest to us. We report the influence of embedded NPs on the luminescence and absorbance characteristics of RE ions doped tellurite glass prepared by melt-quenching method. The absorption and emission spectra displays several prominent peaks corresponding to the transitions from the ground state to the excited states of RE ion. The observed efficient enhancement of up-conversion emissions and absorbance in the entire visible region is attributed to strong localized electric field in vicinity of NPs. Improvements of radiative emissions suggests that the proposed glasses are potential for the development of solid state lasers, color displays and nanophotonic devices.

The Ligand Fields Characterizations within Erbium-Tellurite Glass Network via Gold Nanoparticles Concentration Variation

Glass samples of composition 79TeO2 – 15PbO – 5PbCl2 – 1Er2O3 – (x)AuCl3 with (0.0 ≤ x ≤ 0.1 mol%) were successfully synthesized by using melt-quenching technique. The impacts of gold nanoparticles (GNPs) concentration in stimulating the ligand field interaction inside the erbium-tellurite glass network were inspected. Amorphous nature of the sample was confirmed through XRD pattern. TEM images display the existence of GNPs with average diameter ~1.24 nm. Optical absorption spectra were recorded in the UV-Visible range. The absorption displays several prominent peaks corresponding to the transitions from the ground state to the excited states of Er3+ ion. The compositional dependence of the ligand parameters in terms of crystal field strength and Racah parameter were determined.

Study of Crystallization Kinetics of TeO2-Na2O-MgO Glass Using Ozawa Method: Influence of Europium

. The study of the crystallization kinetics of rare-earth doped glass stimulated much interest especially for crystallization process. In this work transparent Eu2O3 doped glasses with composition TeO2 - Na2O – MgO were prepared using conventional melt-quenching technique. The amorphous nature of glass was confirmed using X-ray diffraction method. The influence of Eu3+ content on the crystallization kinetics of the glass such as activation energy (Ea) was thoroughly evaluated under non-isothermal conditions using DTA. The crystallization kinetic at different heating rate from 5 °C min-1 to 25 °C min-1 at different crystallization temperature (Tp) were examined and verified using Ozawa method. The result showed that the activation energy (Ea) was decreased with the increasing of the dopant concentration from 319.8 eV to 93.5 eV.