Tailoring Spectroscopic Properties of Er3+ doped Zinc Sodium Tellurite Glass via Gold Nanoparticles

Tailoring the spectroscopic properties of rare earth (RE) doped inorganic glasses mediated via surface plasmon resonance (SPR) by embedding metallic nanoparticles (NPs) with controlled concentration is prerequisite for photonic applications. Erbium (Er3+) doped tellurite glasses containing gold (Au) NPs are prepared and systematic characterizations are made to inspect the impacts of Au NPs of spectral features for desired tailoring. X-ray diffraction pattern confirm the amorphous nature of the glass samples and EDX analysis detects elemental traces. The UV-Vis spectra exhibit six absorption bands centered at 488, 523, 655, 800, 973 and 1533 nm corresponding to 4f-4f transitions of Er3+ ions. Glass sample containing 0.4 mol% Au (without Er2O3) reveals Au plasmon band at around 629 nm. The EDX spectra display elemental traces of Te, Er, Zn, Na and Au. Glass sample containing 0.2 mol% Au demonstrates maximum enhancement in the emission band intensity by a factor of 20.23 (orange), 18.35 (strong green), 16.80 (moderate green) and 15.46 (blue). The enhancement is attributed to the Au NPs assisted SPR effect. The beneficial features of proposed glasses nominate them as potential candidate for photonic devices and solid state lasers

Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure

Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies

Up-conversion enhancement in Er 3 +-Ag co-doped zinc tellurite glass: Effect of heat treatment

The melt quenching method was used to synthesize the Ag 0 nanoparticles and Er 3 + ions co-doped zinc tellurite glass. The glasses were characterized by differential thermal analyzer, UV-VIS-IR absorption, photoluminescence spectroscopy and TEM imaging. Heat treatment at different annealing time intervals above the glass transition temperature was applied to reduce the Ag + ions to Ag 0 NPs. The influence of heat treatment on structural and optical properties is examined. Intense and broad up-conversion emissions of silver are recorded in the visible region. Up-conversion luminescence spectra revealed three major emission peaks at 520, 550 and 650 nm originating from 2H 11/2, 4S 3/2 and 4F 9/2 levels, respectively. An efficient enhancement in visible region is observed for samples containing silver NPs. The absorption plasmon peaks are evidenced around 560 and 594 nm. The effect of localized surface plasmon resonance and the energy transfer from the surface of silver NP to trivalent erbium ions are described as the sources of enhancement. © 2012 Elsevier B.V. All rights reserved

The preparation and structural studies in the (80 - x)TeO2-20ZnO-(x)Er2O3 glass system

Er3+-doped tellurite glasses of the (80 − x)TeO2–20ZnO–(x)Er2O3 system (0.5 mol% less-than-or-equals, slant x less-than-or-equals, slant 2.5 mol%) have successfully been made by melt-quenching technique and their structure has been investigated by means of DTA and Raman spectroscopy. The DTA results show the thermal parameters; such as the glass transition temperature (Tg) and crystallization temperature (Tc) were determined. It is found that this system provides a stable and wide glass formation range in which the glass stability around 99–140 °C may be obtained. The Raman spectroscopy used the structural studies in the glass system. Two Raman shift peaks were observed around 640–670 cm−1 and 720–740 cm−1, which correspond to the stretching vibration mode of TeO4 tbp and TeO3 tp, respectively. It is found that the spectral shift in Raman spectra is depending on the Er2O3 content. This evolution is an indication of the changes in the basic unit of the glass structure

Prominent spectral features of Sm3+ ion in disordered zinc tellurite glass

Trivalent rare earth doped glasses with modified spectroscopic features are essential for solid state lasers and diverse photonic applications. Glass composition optimisation may fulfil such demand. Stimulating the spectral properties of samarium (Sm3+) ions in tellurite glass host with desired enhancement is the key issue. Glasses with composition (80 − x)TeO2–20ZnO–(x)Sm2O3, where 0 ⩽ x ⩽ 1.5 mol% are prepared using melt quenching method. The role of varying Sm3+ contents to improving the absorption and emission properties of the prepared glasses are determined. XRD pattern verifies amorphous nature of synthesised glasses. FTIR spectroscopy has been used to observe the structural modification of (TeO4) trigonal bipyramid structural units. DTA traces display prominent transition peaks for glass transition, crystallisation and melting temperature. Samples are discerned to be stable with desired Hruby parameter and superior glass forming ability. The UV–Vis–NIR absorption spectra reveals nine peaks centred at 470, 548, 947, 1085, 1238, 1385, 1492, 1550 and 1589 nm. These bands arise due to 6H5/2 → 4I11/2, 4G5/2, 6F11/2, 6F9/2, 6F7/2, 6F5/2, 6F3/2, 6H15/2 and 6F1/2 transitions, respectively. The direct, indirect band gap and Urbach energy calculated from the absorption edge of UV–Vis–NIR spectra are found to appear within (2.75–3.18) eV, (3.22–3.40) eV, and (0.20–0.31) eV, respectively. The observed increase in refractive index from 2.45 to 2.47 is ascribed to the generation of non-bridging oxygen atoms via the conversion of TeO4 into TeO3 units. Conversely the decrease in refractive index to 2.39 is attributed to the lower ionic radii (1.079 Å) of Sm3+. PL spectra under the excitation of 452 nm display four emission bands centred at 563, 600, 644 and 705 nm corresponding to 4G5/2 → 6H5/2, 6H7/2, 6H9/2 and 6H11/2 transitions of samarium ions. Excellent features of the results nominate these compositions towards prospective applications. Keywords: Tellurite glass, Samarium oxide, FTIR spectroscopy, Absorption, Emissio

Luminescence studies of erbium doped sodium magnesium boro-tellurite glass

The optical behaviour of Er3+ (1.0 - 2.0 mol %) doped B2O3-TeO2- Na2O-MgO glasses synthesized by conventional melt-quenching technique was studied through luminescence measurements. The X-ray diffraction (XRD) pattern confirms the amorphous nature of the glasses without the existence of any sharp peak. The emission spectra at 378 nm excitation displayed three emission peaks corresponding to 2H11/2-4I15/2, 4S3/2-4I15/2 and 4I9/2-4I15/2 transitions. Hence, a schematic energy level diagram was proposed. The luminescence properties of the prepared glasses was found to be strongly affected by varying the concentration of Er3+ ions

Effect of Nd3+ on the properties of lithium niobium borate crystal and glass

1 mol% of neodymium-doped lithium niobium borate (NdLNB) glass and crystal have been produced by using melt-quenching and Czochralski technique, respectively. The synthesis, growth and characterizations of the samples were reported. X-ray diffraction (XRD), Differential thermal analyzer (DTA), Ultraviolet-Visible-Near-Infrared (UV-Vis-NIR) and Photoluminescence (PL) spectroscopic characterizations were made to examine the influence of Nd3+ on the physical, structural and optical properties of the samples. Various physical properties such as density, molar volume, ion concentration, polaron radius, inter-nuclear distance and field strength were calculated. The as-quenched glass was amorphous whereas crystal was crystalline as established via XRD studies. UV-Vis-NIR spectra exhibited eight prominent bands centered at 353, 475, 524, 583, 681, 745, 803, 875 nm corresponding to the transitions from the ground state to 4D3/2, 2G9/2, 4G7/2, 4G5/2, 4F9/2, 4F7/2, 4F5/2, 4F3/2 excited states, respectively. Moreover, the emission spectra at 355 nm excitation displayed several peaks that contributed to the transition of (4F3/2→4I9/2) and (4F3/2→4I11/2), respectively. Fluorescence lifetime was recorded at 53.69 µs for the glass whereas the crystal was recorded at 43.62 µs. It was found that Nd3+ ions affected the physical, structural and optical properties of the glass and crystal samples. *, ,