Search

Cesium lead halide (CsPbX 3 , X = Br, I) perovskite nano-crystals (PNCs) with modified compositions were synthesized within boro-germanate glass ceramics to obtain an efficient red color converter for ultra-high definition (UHD) display application. The glass composition and heat treatment conditions were varied to achieve a high photo-luminescence quantum yield (PLQY) under a blue (450 nm) light emitting diode (LED) excitation. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the formation of CsPb(Br/I) 3 PNCs within the glass matrix. A high PLQY of up to 70.5 % was achieved under 450 nm blue LED excitation. The role of composition on the glass structure and PNC formation as well as PL-QY was investigated by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The stability of the CsPb(Br/I) 3 PNC embedded glass (PNEG) against temperature, water, and continuous LED irradiation was examined, and revealed significantly improved photo, chemical and thermal stability compared to colloidal PNCs. Practical feasibility for display applications was demonstrated by fabricating a white LED using the present red PNEG mixed with green CsPbBr 3 PNEG in a remote phosphor-in-silicone structure, showing a wide color gamut of 138.9 % of the NTSC. [ABSTRACT FROM AUTHOR]

In this investigation, a group of different concentrations of molybdenum trioxide-doped borate-germanate-telluride glasses have been synthesized. Four glasses with a composition formula of (35-x) B 2 O 3 -20TeO 2 -10GeO 2 -35MgO-xMoO 3 where x values vary between 5 and 20 mol % have been achieved using the melt-annealing process. X-ray diffraction for the current M1 sample was utilized to prove the glassy nature. FTIR has been measured to understand the glass structure. Many functional group and vibrational bonds were observed. The optical parameters for B 2 O 3 -TeO 2 -GeO 2 -MgO-MoO 3 glass samples were calculated based on absorption spectra recorded in the 200–1100 nm wavelength range. The optical electronegativity (χ) and optical basicity (Λ) were calculated as critical parameters that can be used to evaluate the glass structure. Physical parameters like density, molar volume (V m), packing density (V t), oxygen packing density (OPD), and oxygen molar volume (OMV) were measured and calculated. Hardness (H), Poisson ratio (σ), Fractal bond conductivity (d), and elastic moduli of M1, M2, M3, and M4 glass samples were calculated. Mass attenuation coefficients (MAC) for four synthesized glass samples were reported along with linear attenuation coefficient (LAC) as a function of photon energy. Based on the transmission factor TF %, it shows extremely low percentages at the lowest energy region, dropping to less than 1 % at 0.015 MeV up to 0.08 MeV in all samples. The radiation protection efficiency (RPE) was examined to measure the samples' capacity to attenuate ionizing radiation. [ABSTRACT FROM AUTHOR]

To study non-traditional glass materials, this investigation created four glass samples composed of (70-x)B 2 O 3 –20TeO 2 -10GeO 2 -xMgO, where x represents the percentage of MgO with values of 20, 25, 30, and 35 mol%. Glasses with high transparency were produced via the accepted melt quenching and annealing method. The samples underwent X-ray diffraction analysis to confirm their glassy structure. Fourier transform infrared spectroscopy was utilized to examine the glass network's various structural groups. The measuring methodology and theoretical calculations were used to calculate a range of physical and mechanical parameters. The cut-off wavelength, as well as the direct and indirect bandgap, and other optical characteristics of the S1–S4 samples were observed using optical absorption. The work utilized Phy-X to acquire the ionizing absorption parameters. The paper demonstrates various glasses' radiation shielding properties, including the effective atomic number, half- and tenth-value layers, linear attenuation coefficient, mass attenuation coefficient, and mean free path. [ABSTRACT FROM AUTHOR]

In this study, we successfully prepared quaternary germanate glasses (Ba x/3 Sr x/3 Ca x/3)Ge (1-x) O 3 (x = 0.1–0.5) using a containerless solidification method. The structure of the germanate amorphous materials was characterized using techniques such as XRD, SEM, TEM and Raman. We evaluated the thermodynamic properties of the amorphous materials using differential scanning calorimetry and investigated their crystallization activation energies. In terms of application performance, we measured electrical conductivity and impedance spectra for the electrical properties, while the optical properties were assessed through the refractive index and transmittance. The results revealed that the (Ba 0.2/3 Sr 0.2/3 Ca 0.2/3)Ge 0.8 O 3 system represented the germanium anomaly point. Due to the highest number of ternary rings and the most compact structure within this system, the values of density, glass transition temperature, refractive index, and bandgap all reached their maximum. As the content of alkaline earth oxides increased, the glass network structure gradually fractured, leading to an increase in non-bridging oxygens and corresponding changes in properties. [ABSTRACT FROM AUTHOR]

Er3+ doped high density germanate glasses with compositions of 50GeO 2 -10BaO–10Al 2 O 3 -15Lu 2 O 3 -(15-x) La 2 O 3 -xEr 2 O 3 (x = 0, 0.1, 0.5, 1.0, 1.5, and 2.0, in mol%) have been prepared by the melt-quenching method. The optical and physical properties of the samples were characterized by differential scanning calorimetry (DSC), density, transmittance spectra, photoluminescence (PL) spectra, and X-ray excited luminescence (XEL) spectra. The densities were in the range from 5.90 to 6.07 g/cm3. The strong green emissions around 552 nm of Er3+ were observed upon the excitations of 378 nm light and the X-ray, and the lifetimes of 552 nm emission were in the range of 20.88–96.47 μs. The results show that Er3+ doped high density germanate glasses could be used as potential scintillators for X-ray CT. [ABSTRACT FROM AUTHOR]

Broadband near-infrared (NIR) spectroscopy based on glass-converted light-emitting diodes (gc-LEDs) has been of great interest to multifunctional applications ranging from night vision to chemical industry, stimulating the demand for exploring broadband NIR gc-LEDs with sufficient efficiency stability and aging resistance. Herein, an all-inorganic broadband NIR LEDs based on Te cluster-doped germanate glass is developed. Via adjustment of melting atmosphere and network topology of the glass matrix, active NIR Te cluster centers can be generated and stabilized in germanate glass and show a broad emission at 770 nm with a full width at half maximum (FWHM) of 260 nm under blue light excitation. By combining the Te-doped glass with a commercial blue LED chip, a high-performance NIR gc-LEDs is fabricated with an NIR output power of 14.21 mW@10.1% under a driving current of 400 mA. Particularly, the fabricated NIR-LED device exhibits high efficient stability with a relatively low-efficiency drop of 0.0023 %mA−1, and excellent aging resistance while retaining an electroluminescence intensity up 90 % of their initial value after aging for 480 h under harsh conditions, which is comparable to the commercial phosphors. Finally, its multifunctional application of gc-LEDs is also demonstrated. [ABSTRACT FROM AUTHOR]

In this work, Tm3+ doped and Tm3+/Ho3+ co-doped germanate glasses with various TiO 2 concentrations have been examined using optical spectroscopy. The broad emission bands corresponding to 3F 4 →3H 6 (1.8 μm) and 5I 7 →5I 8 (2 μm) transitions of thulium and holmium ions were registered, respectively. It was observed that the intensity of near-infrared emission bands significantly changes with increasing titanium oxide content in the glass composition. Furthermore, the energy transfer process from Tm3+ to Ho3+ ions in studied glass systems was confirmed and discussed. The dependence of spectroscopic parameters like full width at half maximum (FWHM) and energy transfer efficiency (η ET) on increased TiO 2 concentration in glass host was established. [ABSTRACT FROM AUTHOR]

The full-spectrum phosphors are key components for improving the light quality of phosphor-converted white light-emitting diodes (pc-WLEDs). In this work, a novel germanate glass-ceramic (GC) doped with Mn2+ was developed to achieve full-spectrum white light emission deriving from the defective Zn 2 GeO 4 crystalline phase and Mn2+ with multisite occupancy. The defective Zn 2 GeO 4 is crystallized in situ from the well-designed precursor germanate glass by a controllable heat treatment. The energy states of intrinsic defects, including oxygen and zinc vacancies and interstitial zinc and oxygen of Zn 2 GeO 4 in GC, have been studied by first-principles calculations. The luminescence property and the energy transfer mechanism between the defect states and Mn2+ ions in the GC material was proposed. Under the UV excitation, the luminescence property can be tuned by adjusting the distribution of Mn2+ ions in between the glassy and crystalline phases. The correlated color temperature (CCT) and color rendering index (CRI) of the UV-excited full-spectrum white light emission can be tuned over a wide range. This combinatorial strategy of intrinsic defects and multisite ion doping for full-spectrum white light emission in GC, which overcomes the limitation of conventional discontinuous white light emitting materials that emit singly from doping ions, has shown good potential for application in pc-WLEDs. [ABSTRACT FROM AUTHOR]

We prepared novel barium germanium (BaO–GeO 2) glass samples with varying BaO concentrations and investigated their physical and optical properties. We analyzed the refractive indices, glass transition temperatures (T g s), molar volumes, and optical band gaps of the samples, which were measured and plotted against their BaO concentrations. The results showed that refractive indices, T g s, molar volumes, and coefficients of thermal expansion increased with BaO concentration. Raman spectra showed structural network modifications and typical Germanium glass bands. The band at ∼ 529 cm−1 was assigned to vibration bonds of Ge(4)-O-Ge(4), and that at ∼ 823 cm−1 was attributed to stretching vibration of non-bridging oxygen (NBO) atoms. [ABSTRACT FROM AUTHOR]

Germanate-based oxyfluoride transparent glass-ceramic functionalized by Tm3+:Ca 2 YbF 7 nanocrystals was newly developed. The tremendously enhanced upconversion emission of 3F 2,3 energy levels by in situ crystallization was extremely beneficial for constructing optical thermometry involving the indirect thermally coupled energy levels (1G 4 and 3F 2,3) of Tm3+ ions. Utilizing the fluorescence intensity ratio technique, the thermometry potentials of PG and GC8 were systematically evaluated based on the emissions from 3F 2,3 and 1G 4 energy levels. The relative and absolute sensitivities, thermometry resolutions, and repeatabilities were superior to many reported materials. This work provides an avenue for precipitating ternary fluoride nanocrystals containing rare earths in germanate-based oxyfluoride glass, and proposes a promising way to achieve high performance optical thermometry based on the emissions from widely spaced energy levels. [ABSTRACT FROM AUTHOR]

Pr3+ doped high density germanate glasses were prepared by the melt-quenching method. The physical and luminescent properties were investigated. The glass containing BaF 2 represented maximum phonon energy of 810 cm−1, and the glass density was greater than 6 g/cm3. The glass exhibited good radiation resistance under 2 h of X-ray irradiation. Intense blue, green emissions and weak red emissions were observed when the glass was excited by X-ray, and the blue fluorescence lifetimes were in the range of 9.15–12.59 μs The results show that Pr3+ doped germanate glass could be a potential scintillating material in the field of X-ray detection for fast events. [ABSTRACT FROM AUTHOR]

• Germanium-based glass materials were prepared by employing a high-temperature melting method, and then graphene-glass composite anode materials were prepared by ball-milling technique. • The prepared composite glass anode has a stable structure and shows high capacity performance, the discharge/charge specific capacity reached 1108.2/1098.6 mAh g-1 after 450 cycles at a current density of 500 mA g-1. • The results show that the introduction of graphene provides a good layer structure to provide a buffer space for dealing with the internal stresses generated by the embedded lithium ions in the alloying reaction, as well as reducing the volume expansion of the germanium-based glass anode during cycling. The performance of a lithium-ion battery (LIB) is largely contingent upon its anode material. At present, germanium-based anode materials are of interest due to their high theoretical capacity, but there are fewer studies on germanium-based glass anode materials. In this work, graphene mixed germanium-based glass composite material was fabricated utilizing the ball-milling technique. The addition of graphene greatly reduces the charge transfer resistance of the germanium-based glass anode during cycling. Meanwhile, the composite anode exhibited a high specific capacity of 1101.5 mAh g-1 during the first discharge cycle, and the discharge/charge specific capacity was still as high as 1108.2/1098.6 mAh g-1 after 450 cycles at a current density of 500 mA g-1. Moreover, at a high current of 2 A g-1, the composite anode still maintains a high discharge specific capacity of 437.2 mAh g-1, and there is no obvious swelling on the surface, showing excellent stability. It is hoped that the current research endeavor may offer a fresh direction for future studies aimed at optimizing germanium-based glass anode materials. [ABSTRACT FROM AUTHOR]

Glasses in the system BaO – La 2 O 3 – Ga 2 O 3 – GeO 2 and Langasite crystalline phases with the same stoichiometry have been studied considering the possible use of these glasses for laser-induced space-selective growth of crystalline architectures in the glass compositions. For better understanding of mechanisms involved in such controlled crystallization process, crystalline and glass compounds with same stoichiometry and different La/Ba ratios have been synthesized to compare their local structure. Solid-state Nuclear Magnetic Resonance evidence 4- and 5-coordinated gallium units in the glass matrix, denying unambiguously the formation of 6-coordinated gallium sites observed in crystalline phases. Moreover vibrational spectroscopies suggest a link between a 3D network formed by 4- and 5-coordinated gallium, connected to each other and to 4- coordinated Q4 and Q3 germanium units in the glass and their congruent crystallization. The transition from 4- and 5-coordinated gallium to 6-coordinated gallium sites observed in Langasite crystalline phases remains not still elucidated. [ABSTRACT FROM AUTHOR]

Red-emitting perovskite quantum dots (QDs) have significant potential for application in optoelectronic devices. However, their application is hindered by preparation challenges and low photoluminescence quantum yield (PLQY). In this study, CsPbBrI 2 red-emitting QDs with a PLQY of up to 58.73 % were synthesized in germanium borate glass. The experimental results indicated that the addition of Nb5+ can not only partially replace the Pb2+ sites but also passivate halogen defects in QDs, enhance radiative transitions, and significantly improve the lattice ordering of CsPbBrI 2 QDs glass. Additionally, the incorporation of Nb 2 O 5 supplies free oxygen, facilitating the conversion of [BO 4 ] to [BO 3 ] in the glass network, which results in a looser structure conducive to crystallization. Moreover, the Nb5+-doped CsPbBrI 2 QDs glass demonstrated excellent hydrothermal stability. The QDs glass exhibiting the highest luminescent performance was subsequently combined with an InGaN blue chip to create a WLED with a color rendering index (CRI) of 82.7. This study offers an innovative methodology for synthesizing perovskite QDs glass materials with enhanced red emission efficiency through transition metal doping, highlighting their significant potential for practical applications in WLEDs. • Nb5+ modified red-emitting CsPbBrI 2 quantum dots glass with PLQY up to 58.73 %. • Nb5+ can partially replace Pb2+ sites and passivate halogen defects in QDs. • Nb 2 O 5 converts [BO 4 ] to [BO 3 ], optimize the crystallization behavior of QDs. • The obtained glasses exhibit excellent water and thermal stability. • A WLED with a CRI of 82.7, CCT of 6495 K and LE of 72.82 lm/W is constructed. [ABSTRACT FROM AUTHOR]

The current investigation studied one of the high-density heavy metal oxides (Bi 2 O 3) having density = 8.9 g/cm³, which was utilized to improve structural and optical features of the B 2 O 3 –TeO 2 -GeO 2 -MgO glass system. Three high transparent glasses with a chemical formula of 35B 2 O 3 –20TeO 2 -10GeO 2 -35MgO-xBi 2 O 3 (x = 5, 10, and 15 mol %) were fabricated by melting at 1100 °C for 20 min and annealing at 400 °C for 5 h. X-ray diffraction measurements for the Bi5 sample, containing 5 mol % Bi 2 O 3 , were obtained at the range of 10°–80° to inspect the structural characteristics of the made glasses. Optical absorption was employed and recorded for Bi5, Bi10, and Bi15 samples at wavelength range 300–1000 nm to examine the optical properties, including optical band gap. Using Makishima and Mackenzie methods, the mechanical features of the glass samples were assessed. Nuclear library ENDF/B-VI.8 is coupled to the MCNP-5 code and is used to study and simulate the prepared Bi glass sample shielding parameters. The ionizing absorption properties for the prepared Bi5, Bi10, and Bi15 samples were found to be changed because of many circumstances like the photon energy (Eγ, MeV), and chemical compositions (Bi 2 O 3 content (mol. %). The increased layer thickness of glass between 25 and 200 mm enhances the RPE values at 0.6 MeV over the range of 16.31–50.93 % (Bi5 glass sample), 18.68–56.26 % (Bi10 glass sample), and 20.80–60.66 % (Bi15 glass sample). • Four glasses with composition of 35B 2 O 3 –20TeO 2 -10GeO 2 -35MgO-xBi 2 O 3 , (x = 5, 10, and 15 mol%) have been synthesized. • The melt-quenching-annealing process was employed in the synthesis of the glass system. • X-ray diffractometer confirms the amorphous structure of the glasses. • The RPE for all prepared glass samples reaches 100 % at 0.06 MeV. [ABSTRACT FROM AUTHOR]

In the present work, a group of four glass samples that have chemical composition of [(35-x) B 2 O 3 -20TeO 2 -10GeO 2 -35MgO-xLa 2 O 3 ] were x values varies from 2.5 to 10 all in mol percentage, which fabricated using ordinary melting then quenching technique. Many physical and mechanical have been measured and calculated like: density, packing density, internuclear distance (r i), oxygen packing density (OPD), oxygen molar volume (OMV), dissociation energy (G t), packing density (V t), Poisson ratio (σ), fractal bond connectivity (d), elastic modulus. The behavior of the La10 was examined using XRD in the range of 10–80°. The UV–visible spectrum of absorption of the La2.5, La5, La7.5, and La10 glasses were measured. Several optical parameters have been calculated and extracted including the cutoff wavelength, Urbach's energy (E U), dielectric constant (ε), refractive index (n), molar refraction (R M), reflection loss (R L), molar electron polarizability (α M), Optical transmission (T), Optical basicity (Λ), and Metallization criteria (M). Various noticeable bands vibration of boron units structural besides the modes of vibration of that effected by adding metal cations were studied using FTIR to analyze different structure groups like: BO 3 triangles, BO 4 pyramids, tetragonal TeO 4 pyramids, and trigonal TeO 3 pyramids. Using Monte Carlo simulation, the MAC of glass materials was evaluated in the current work. Various radiation shielding parameters were investigated at low and high energies. [ABSTRACT FROM AUTHOR]

In this paper, we designed the glass composition and optimized the Tm3+ doping concentration to obtain a tellurite-germanate laser glass material with favorable luminescence in the ∼2 μm wavelength band. The optical features of the glass samples and the energy transfer behavior between rare-earth ions (Tm3+) were investigated comprehensively. Information on the internal structural units and various physical properties of the glass samples were determined. Combining the measured and calculated data of the experimental samples, it is clear that when doped with 1.25 mol% Tm 2 O 3 , the TGFT4 glass sample not only achieves a lower OH− content, but also has a good advantage in emission cross section, gain coefficient, spectroscopic figure of merit (FOM) and energy transfer rate. Furthermore, the tellurite-germanate glasses exhibit good thermodynamic properties. All the results suggest that Tm3+ doped tellurite-germanate glass materials are potentially competitive and applicable in the field of optical communication and laser design. [ABSTRACT FROM AUTHOR]

To achieve a tunable and high-color-rendering white light emission in full visible spectral range, the Ag-aggregates/Sm3+ co-doped germanate glass fluorophors were prepared by a melt-quenching method. Under the excitation of different wavelengths, the intense broadband emissions covering full visible spectral range from blue to red were gained in the germanate glasses only containing Ag-aggregates. From the optical spectral analyses, it was found that with increasing the excitation wavelengths, the emission peak position exhibits red-shift. However, the red component in the emission spectra is still of relative lack for realizing high quality white light, therefore Sm3+ was introduced as co-dopant to supply the red spectral component. In this way, a series of chroma-tunable and full-color-emitting white lights with color coordinates from (0.26, 0.25) to (0.30, 0.32) were successfully realized based on adjusting the excitation wavelengths and Sm3+ concentration. Particularly, the color rendering index (CRI) up to 97.6 was achieved. Furthermore, the luminescence thermal stability of Ag-aggregates/Sm3+ co-doped germanate glass fluorophors was investigated based on the Arrhenius model, and the corresponding Δ E values for Ag aggregates and Sm3+ emissions were confirmed to be 0.25 and 0.19 eV, respectively. In addition, a temperature sensing model was established based on the luminescence intensity ratio of Ag-aggregates to Sm3+, and the thermochromatic property of Ag-aggregates/Sm3+ co-doped germanate glasses was also evaluated. It was found that the luminescence color coordinates of Ag-aggregates/Sm3+ co-doped glass fluorophors always lie in the white light region when the sample temperature increases from 301 to 693 K, thus indicating that Ag-aggregates/Sm3+ co-doped glass fluorophors have potential application in solid-state lighting sources as a single-component white lighting material. [ABSTRACT FROM AUTHOR]

· Study of lead germanate glasses by neutron diffraction, RMC, DSC and Raman analysis. · Density increases while Tg and atomic number density decrease with an increase in PbO mol%. · Ge-O co-ordination essentially tetrahedral and in the range: 3.9 to 4.2(1). · Small amount of GeO 3 and GeO 5 but no GeO 6 units in glass structure. · Pb-O co-ordination decreases from 4.0 to 3.1(1) with increase in PbO mol%. The effects of PbO concentration on the density, thermal and structural properties of xPbO–(100-x)GeO 2 (x = 20 to 55 mol%) glasses were studied. Density of glasses increases linearly from 5.043 to 6.981(5) g·cm−3, while the glass transition temperature decreases drastically from 467 °C to 359 °C on increasing PbO concentration from 20 to 55 mol%. Neutron diffraction studies found that Ge-O co-ordination is in the range: 3.9–4.2(1), and there is a very weak germanate co-ordination anomaly at PbO concentration of 40 and 50 mol%. GeO 4 are the dominant structural units with a small quantity of GeO 3 and GeO 5 but very little GeO 6 in the glass network. Pb-O and O O co-ordination decreases with an increase in PbO mol% and are in the range of: 4.0–3.1(1) and 6.3–5.4(1) respectively. Raman studies indicate a decrease in Pb-O co-ordination with increase in PbO mol%, in good agreement with the neutron diffraction findings. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fabrication of novel GeSbNaB:Eu3+ lasing material by melt-quenching Technique. • Structural disorder of the glasses is detected with the incorporation of Eu3+ ions. • The trend Ω 2 > Ω 4 > Ω 6 confirmed the covalent nature the as developed glasses. • PL, quantum efficiency and fluorescence intensity ratio (R) are highest for1.0 Eu glass. • GeSbNaB:Eu3+stands out as a solid state active laser medium for intense red emission. Glasses activated with europium show promising potential for use in applications relating to photonics, in particular solid-state laser generation. In the current work, Eu 2 O 3 incorporated gemanium borate glasses were developed and explored their potentiality towards lasing active medium by probing physical, structural, optical and lasing properties in detail. The physical and structural features of each glass indicated the presence of non-bridging oxygens (NBOs) and an enhancement in network stability on account of the inclusion of europium ions into the GeO 2 glass network. Optical energy band gaps, E d , E o , n o , S o , and λ o values were obtained by absorption spectra and found to be increased with europium content. The sequence of Judd-Ofelt (JO) intensity parameters (Ω 2 , Ω 4 , and Ω 6) exhibited the trend Ω 2 > Ω 4 > Ω 6 , and it confirmed the covalent nature of the as-developed glasses. 1 mol% Eu 2 O 3 doped glasses exhibited the highest photoluminescence, quantum efficiency and fluorescence intensity ratio (R). The decay profiles showed single exponential nature for 5D 0 state of Eu3+ ions and their lifetime values were calculated. The results amply demonstrated the viability of the manufactured glasses as a potential solid-state active laser medium, with the CIE diagram confirming the intense red color emission as seen from the PL spectra. [ABSTRACT FROM AUTHOR]

Glass compounds have gained attention as scintillating materials owing to their large production possibility, easy shaping and flexible glass composition, and various glasses such as silicate, germanate and borate glasses have been considered for scintillator applications. Herein, Eu 2 O 3 -doped bismuth gallate glasses having a composition of 5K 2 O–70Bi 2 O 3 –25Ga 2 O 3 were synthesized for the development of new glass scintillators by the melt-quenching method. After the fabrication of the undoped and Eu 2 O 3 -doped bismuth gallate glasses, their optical and scintillation characteristics were evaluated. The Eu 2 O 3 -doped bismuth gallate glasses showed photoluminescence (PL) and scintillation with sharp peaks centered at approximately 596 and 612 nm due to the electronic 4f → 4f transitions of Eu3+. The PL and scintillation spectra revealed that the concentration dependence of the PL quantum efficiency for the Eu 2 O 3 -doped bismuth gallate glasses was well correlated with that of the scintillation intensity. The decay time constants of the 0.5% and 1.0% Eu 2 O 3 -doped bismuth gallate glasses under visible light and X-ray irradiation were approximately 0.55 ms and 0.15 ms, respectively. In addition, the undoped and Eu 2 O 3 -doped bismuth gallate glasses exhibited afterglow levels of 330–660 ppm, and their moderate levels were found to be almost comparable to the afterglow level of Tl-doped CsI. [ABSTRACT FROM AUTHOR]

Gamma radiation, neutrons, protons, and alphas particles shielding competences for gallium germanate-tellurite (GeO 2.TeO 2.Ga 2 O 3) glasses doped with Pr 6 O 11 were tested. The investigated glasses were named as GTGPr1, GTGPr2, GTGPr3, and GTGPr4. Mass attenuation coefficients (MAC) for the proposed glasses were calculated utilizing Phy-X/PSD program and simulated by MCNP5 simulation codes in the photon energy range of 0.015–15 MeV. With the help of MAC values, the linear attenuation coefficient (LAC), half value layer (HVL), mean free path (MFP), and effective atomic number (Z eff) were calculated. Moreover, the absorbed dose received from 137Cs with activity 10 μCi was calculated in presence of the studied glasses. Buildup factors (BUFs) include exposure buildup factor (EBF), and energy absorption buildup factor (EABF) for all investigated glasses were also calculated. Results reflected that the GTGPr4 glass has the highest MAC, LAC values and lowest HVL among other selected germanate glasses. The values of Z eff were around 0.04 MeV varied between 43.07 and 48.19, while at 1.5 MeV were between 18.70 and 21.25. The GTGPr1 possesses the highest values of BUFs around the studied range of energy, while GTGPr4 glasses possesses the lowest values. Moreover, the fast neutron removal cross section was (Σ R = 0.02151 and 0.01942 cm2 g−1) for GTGPr1 and GTGPr4, respectively. The investigated glasses can be useful to construct superior radiation shielding materials to use in nuclear medicine applications. [ABSTRACT FROM AUTHOR]

In this study, mechanical and nuclear radiation shielding behaviors of highly efficient alkaline phosphate glasses with various GeO 2 concentrations were evaluated for their nuclear radiation shielding applications. Moreover, the glass rigidity parameters of alkaline phosphate glasses were calculated for determination mechanical properties. The μ m values were calculated using XCOM program and MCNPX simulation code. The nuclear radiation shielding properties (gamma and neutron) such as μ m , HVL, TVL, MFP, Z eff , EBF, EABF, and Σ R were calculated for all alkaline phosphate glasses with various GeO 2 concentrations. The results showed that μ m , Z eff , and Σ R increased as the Bi 2 O 3 concentration increased. The G14 glass sample had the minimum HVL, TVL, MFP, EBF and EABF. The G14 sample had the largest μ m , Z eff , and the number of network bonds, and can be considered as an excellent attenuator for gamma and neutron shielding. The outcomes of recent investigation can be useful to understand the nature of GeO 2 additive into alkaline phosphate glasses, which can be considered as a candidate shield type in medical and industrial radiation facilities. [ABSTRACT FROM AUTHOR]

Oxyfluoride silicate glasses co-doped with Cr3+ and Yb3+ ions were fabricated in this work. High △T (178–214 °C) value demonstrated that the thermal stability of the prepared glasses were better than tellurite and germanate glasses. X-ray diffraction (XRD) curves proved the amorphous nature of the glasses, the energy dispersive spectroscopy (EDS) analysis and Fourier Transform infrared spectroscopy (FT-IR) curves explored the network structure of glasses. The photoluminescence excitation (PLE) and photoluminescence emission (PL) spectra show that the glasses absorption peaks located at 430 nm (Cr3+:4A 2g - 4T 1g (P)) and 627 nm (Cr3+:4A 2g - 4T 2g), while the emission peak close to 1010 nm (Yb3+:2F 5/2 -2F 7/2), which meets the condition of energy down-conversion. Besides, the energy transfer efficiency (η CET = 33.5%) and the quantum cutting efficiency (η QE = 133.5%) were calculated from the measured decay curves. These values were higher than Cr3+/Yb3+ co-doped fluorosilicate glass with incorporating of CaF 2 (21.5% and 123.5%) and Tb3+/Yb3+ oxyfluoride glass (13.5% and 113.5%), indicating the prepared samples are conducive to the energy transfer from Cr3+ to Yb3+ ions. The experimental results reveal that the oxyfluoride silicate glasses have potential application prospects in crystalline silicon (c-Si) solar cells. [ABSTRACT FROM AUTHOR]

A kind of bismuth-doped silica glasses have been produced successfully by spark plasma sintering at 1070 °C using bismuth-doped SBA-15 powders. The samples were detected by X-ray diffraction, UV–vis–NIR, photoluminescence, fluorescent decay curve and X-ray photoelectron spectroscopy. The results showed that the samples possess favorable near-infrared fluorescence and the 0.9 mol% sample is the best one among these glasses. The emission peaks at ~1180, ~1150 and ~1250 nm can be observed when excited by 500, 700 and 800 nm. The average lifetimes of 0.9 mol% under 500, 700 and 800 nm excitation are 189.87, 311.46 and 132.16 μs. Furthermore, the value of the important optical parameter σ em τ is 5.79 × 10−24 cm2s at 800 nm excitations, which is 36.8% and 9.2% larger than bismuth-doped germanate glasses and phosphate glasses that have been reported. These emission peaks could be decomposed into three bands at ~1150, ~1240 and ~1440 nm via Gaussian decomposition. Based on the results of this work, it is concluded that the NIR emission peaks at ~1150, ~1240 and ~1440 nm correspond to Bi0, Bi+ and (Bi 2)2-, respectively. This glass with excellent luminescence properties could offer a practical material to improve the performance of broadband fiber amplifiers and tunable lasers. [ABSTRACT FROM AUTHOR]

CsPbX 3 (X = Cl, Br, I) perovskite quantum dots (QDs) have attracted extensive attention due to their great application prospects in the photoelectronic field. However, the poor long-term stability still limits their practical use. In this work, a whole series of CsPbX 3 QDs were precipitated in a germanate glass matrix by a melt quenching method. The emission wavelength can be tunable in the entire visible spectral region by adjusting of the halide ions and the thermal treatment process. The photoluminescence quantum yield of CsPbBr x I 3-x QDs glass can reach up to 38.24%. The exciton binding energies of CsPbBr x Cl 3-x , CsPbBr 3 and CsPbI 3 QDs glass are about 67 meV, 160 meV and 290 meV, respectively. Additionally, the influence of the thermal treatment temperature on photoluminescence properties of CsPbBr x I 3-x QDs glass was investigated in detail. These results will be of benefitting to their practical applications, such as display devices and WLEDs. • A whole series of CsPbX 3 (X = Cl, Br, I) QDs were precipitated in germanate glass matrix. • Emission wavelength can be tunable in the whole visible spectral region by adjusting the halide ions. • Exciton binding energy of CsPbX 3 QDs glass increases as the halide ions change from Cl to I. • The obtained QDs glass can be potential applications in WLEDs, display devices, etc. [ABSTRACT FROM AUTHOR]

Ce3+ activated high-density lanthanum lutetium germanate glass was fabricated by melt quenching method. Their densities, fluorescence decay curves, transmittance spectra, and luminescence excited by UV light and X-ray were measured and investigated. The densities of the glasses are between 5.90 g/cm3 and 5.97 g/cm3. The glasses present blue emission upon 379 nm light and X-ray. The blue emission lifetimes of the glasses are between 11.26 ns and 18.83 ns. The results shows that Ce3+ activated high-density lanthanum lutetium germanate glass would be a potential fast-event X-ray detection scintillating material. • Ce3+ doped germanate glasses with density around 6 g/cm3 were prepared. • The glass showed blue emissions upon UV light and X-ray. • The blue emission lifetimes were in the range of 11.26–18.83 ns. [ABSTRACT FROM AUTHOR]

This study aimed to examine the radiation shielding capabilities of four distinct germanate glass systems with compositions of TeO 2 -GeO 2 -ZnO, B 2 O 3 -GeO 2 -Eu 2 O 3 -R 2 O 3 (where R Y, La and Gd), Li 2 O–Sb 2 O 3 - GeO 2 -XO (where X = Pb, Zn, Ba, Sr and Ca) and Li 2 O-GeO 2 -PbO-Nd 2 O 3 at different photon energies ranging from 0.015 to 10 MeV respectively. The present study involved the determination of mass attenuation coefficients (MAC), effective atomic number (Z eff), and half value layer for four distinct germanate glass systems. The influence of chemical composition, sample density, and photon energy on these parameters was also discussed. The findings indicate that the substitution of TeO 2 with ZnO leads to a reduction in the values of both the mass attenuation coefficient (MAC) and the effective atomic number (Z eff) in the glasses composed of TeO 2 -GeO 2 -ZnO. Furthermore, it has been discovered that within the B 2 O 3 -GeO 2 -Eu 2 O 3 -R 2 O 3 glass system, the highest values of MAC are observed in the glass containing Gd 2 O 3. The sample that contained PbO exhibited the highest MAC and Z eff values among the Li 2 O–Sb 2 O 3 -GeO 2 -XO glass systems. Furthermore, the findings of this study indicate that the glass specimen containing CaO exhibits the least values of MAC and Z eff within the given system. The findings indicate that the values of MAC in the Li 2 O-GeO 2 -PbO-Nd 2 O 3 glass system exhibit an upward trend with the rise in Nd 2 O 3 concentration from 0 to 2 mol%. • Radiation shielding characteristics of various GeO 2 glasses have been studied. • XCOM program were studied at several photon energies between 0.015 and 10 MeV. • Gamma photons absorption capacity increases when density of the sample increases. • High density glasses promising effective radiation shielding. [ABSTRACT FROM AUTHOR]

In recent years, perovskite quantum dots (QDs) have emerged as a star of the materials world based on their extraordinary optical properties. Nevertheless, the photoluminescence performance (PL) and stability of QDs need to be further improved. In this work, CsPbBr 3 QDs glass with high photoluminescence quantum yield (PLQY) and excellent hydro-stability was manufactured utilizing a high temperature fusion process and followed heat treatment. By adjusting the concentration of CaO, the PLQY of CsPbBr 3 QDs glass increased from 7.78% to 64.52%. The consequence confirmed that CaO addition loosened the glass structure together with accelerated atomic migration and reorganization at lower polymerization states, thereby promoting the precipitation and growth of QDs. Significantly, after 33 days of immersion testing, the glass sample maintained excellent luminescence, which was attributed to the protection of the PbBr(OH) hydration layer. Furthermore, CsPbBr 3 QDs glass maintained 71% of original PL intensity after three heating and cooling cycles, indicating that the prepared sample had good thermal stability. This work provided new insights into the relationship between network structure and CsPbBr 3 QDs crystallization, and had certain reference value for improving the PL performance and water stability of CsPbBr 3 QDs. • CaO-modified CsPbBr 3 quantum dots glass is obtained by high temperature melting method. • The sample PLQY increases from 7.78% to 64.52% with increase CaO concentration. • After 33 days of immersion testing, the samples maintain excellent luminescence. • The samples retain 71% of original luminescence after three heating/cooling cycles. [ABSTRACT FROM AUTHOR]

In this work structural and luminescence properties of gallo-germanate glasses were investigated. The mentioned glass system was modified with barium and antimony oxides and doped with Eu3+ ions. The starting glass consisted of barium oxide as a modifier which was then gradually replaced by antimony oxide to form six glass samples. The gallo-germanate glass as a low-phonon host for RE (Rare Earths) ions is a promising material for optoelectronics. However, luminescence properties closely depend on material composition. For this reason, structural changes in studied materials were induced by changing its chemical composition and the luminescence properties were tested. The FT-IR (Fourier-Transform Infrared Spectroscopy) and the Raman spectra of studied glasses illustrate the tendency to increasing quantity of bridging oxygen connecting germanium ions and decreasing quantity of non-bridging oxygen along with antimony oxide addition. Simultaneously the BP (Boson Peak) measurements and emission spectra of Eu3+ ions show an increasing tendency to the examined glass structure ordering along with modifier oxide addition. [ABSTRACT FROM AUTHOR]

We present the synthesis and nuclear radiation shielding characterization of glasses based on germanium and bismuth oxide prepared with the melt-quenching technique. The glasses were produced using six different compositions as follows (in wt%): 40.0GeO 2 -60.0PbO, 38.0GeO 2 -62.0Bi 2 O 3 , 31.344GeO 2 -41.900Bi 2 O 3 -26.756PbO, 33.334GeO 2 -33.333TeO 2 -33.333PbO, 20.6GeO 2 -41.9TeO 2 -17.4Nb 2 O 5 -20.1BaO, 41.98Bi 2 O 3 -48.26PbO-8.10Ga 2 O 3 -1.66BaO. Monte Carlo method (MCNPX code, v-2.6.0) has been utilized for the determination of mass attenuation coefficients (μ/ρ) of the synthesised six different glasses. The acquired mass attenuation coefficients (μ/ρ) have been used to determine the vital parameters for gamma-ray shielding namely half value layer (HVL), mean free path (MFP), tenth value layer (TVL), effective atomic number (Zeff), exposure buildup factor (EBF), energy absorption buildup factor (EABF), transmission factors (TF), respectively. Simultaneously, effective removal cross section (∑R) values for fast neutrons and Proton mass stopping power & proton projected range have been also calculated. The results showed that among all the investigated glasses, 41.98Bi 2 O 3 -48.26PbO-8.10Ga 2 O 3 -1.66BaO glass sample has the extra capability to reduce nuclear radiation as a shielding material. [ABSTRACT FROM AUTHOR]

Eu3+-, Er3+-doped and Er3+/Yb3+-codoped niobium alkali germanate glasses, in the compositional host system GeO 2 -Nb 2 O 5 -K 2 O were synthesized by the conventional melt-quenching technique. Glass-ceramics were manufactured by controlled heat treatment of the precursor glasses. Homogeneous glasses and nanocrystalline glass-ceramics were investigated by DSC, XRD, TEM and spectroscopic analysis. K 2 Nb 14 O 36 crystals are formed in the prepared glass-ceramics. This crystalline phase has low phonon energy as compared to the precursor glass and a variety of chemical sites for rare-earth ions. In glass-ceramics, the rare-earth ions occupy higher symmetry sites of the K 2 Nb 14 O 36 nanocrystals resulting in inhomogeneous broadband emissions. Judd-Ofelt parameters were obtained for the Eu3+- and Er3+-doped samples. Glass-ceramics heat-treated for 20 h exhibited the highest photoluminescence quantum efficiency. The increased quantum efficiency is due to the decrease of nonradiative decay processes, that depopulate the excited levels, as well as the decrease in hydroxyl content and overall phonon energy. However, luminescence quenching is verified for samples with longer crystallization times, which emphasizes the importance of optimized heat treatment parameters. The gain coefficient and upconversion data were obtained and corroborate the potential application of these materials as photonic devices, such as visible and NIR laser and optical amplifiers. Image 1 [ABSTRACT FROM AUTHOR]

Crystallization processes of bismuth germanate glasses may be evidenced by the optical properties of Eu3+ ions, used as probes because these ions substitute the Bi3+ ions in the glass-ceramic samples. The gradual thermal annealing of these glasses induces rearranging of GeO 4 tetrahedra around Bi3+ ions and transforms the red colored glasses in transparent glass-ceramic samples. The red color comes from the light scattering on GeO 4 clusters and, after rearranging in Bi 4 Ge 3 O 12 nanoparticles, convert the glass-ceramic samples in transparent materials. One of the most essential information is given by the phonon side bands investigations which, coupled with the Raman spectra allows the identification of Bi 4 Ge 3 O 12 lattice vibration but also those of residual GeO 4 tetrahedra. The measurements of the luminance and CIE circle have shown a significant increase of the light emission for the glass-ceramic samples, while the Magnetic Circular Dichroism indicate lower symmetry coordination around the Eu3+ ions in the glass sample compared with the glass-ceramic and also a change in the coordination number to the higher values. Image 1 [ABSTRACT FROM AUTHOR]

In this work, a multicomponent GeO 2 –Sb 2 O 3 –BaO (BSG) glass is explored to assess its potential for 1.06 μm fiber lasers. The glass-forming region of BSG system is predicted and determined experimentally based on a thermodynamic method. Benefitting from the incorporation of Sb 2 O 3 , this system possesses an exceptionally large glass-forming region, as well as high density and refractive index, wide infrared transmission range and low phonon energy. Furthermore, an efficient near-infrared emission at 1064 nm from Nd3+ has been realized in this oxide glass with relatively long measured lifetime (200.58 ± 1.24 μs) and large emission cross-section (3.015 ± 0.090 × 10−20 cm2), indicating that Nd3+-doped BSG glass is a promising candidate for laser application in 1.06 μm region. • Nd3+-doped GeO 2 -Sb 2 O 3 -BaO antimony germanate glasses were synthesized. • The glass-forming region of the BSG system was predicted via a thermodynamic method. • The physical, structural and spectrographic properties of the BSG glasses were investigated. [ABSTRACT FROM AUTHOR]

Barium gallo-germanate glasses co-doped with Ce3+ and Dy3+ were synthesized and their luminescence properties were studied using optical spectroscopy. The characteristic luminescence bands originating to electronic transitions of Ce3+ and Dy3+ ions were observed under direct excitation of Ce3+. Furthermore, the influence of rare earth ions concentration on luminescence properties of glass systems was examined. Luminescence lifetimes for the upper 4F 9/2 excited state of Dy3+ ions were also evaluated and discussed in detail. The obtained experimental results indicate that energy transfer between these rare earth ions is possible. From the emission spectra, the Commission Internationale de I'Eclairage (CIE) chromaticity coordinates (x, y) are calculated in relation to potential application of germanate glass systems for white light emitting devices. It has been proved that our glass systems exhibit neutral/cool white emission originating from the simultaneous generation of several bands of Ce3+ and Dy3+ under the UV–visible light excitation. [ABSTRACT FROM AUTHOR]

Abstract Radiation shielding characteristics of different germanate glasses with compositions of Nd doped Bi 2 O 3 –SiO 2 /GeO 2 –Nd 2 O 3 , Sm3+ doped B 2 O 3 –GeO 2 –Gd 2 O 3 , Tb3 doped GeO 2 –B 2 O 3 –SiO 2 –Ga 2 O 3 , TeO 2 –GeO 2 –Li 2 O and Na 2 O–GeO 2 –P 2 O 5 glasses have been studied using XCOM program at several photon energies between 0.015 and 10 MeV. Dependencies of their photon attenuation properties with the photon energy and the composition have been investigated. The mass attenuation coefficient values and the effective atomic numbers for Nd doped Bi 2 O 3 –SiO 2 /GeO 2 –Nd 2 O 3 glasses are higher than those of the other samples. 69Bi 2 O 3 –30GeO 2 –1.0Nd 2 O 3 has the highest mass attenuation coefficients among the selected samples. The Z eff results revealed that to increase the photon attenuation ability for the germanate glasses, high Z -elements (such as Bi, Te and Tb) in a suitable concentration must be included. The HVL results for the present germanate glasses suggested that the attenuation capacity of the gamma photons increases as the density of the sample increases, hence, the glass sample with high density must be considered for high attenuation ability. Also, the significant influence of modifier contents on the HVL values namely the attenuation ability has been noticed for Tb3 doped GeO 2 –B 2 O 3 –SiO 2 –Ga 2 O 3 and TeO 2 –Li 2 O–GeO 2 glasses. Moreover, the values of the mean free path for the selected samples have been compared with those of different radiation shielding glasses and concrete samples. Highlights • Radiation shielding characteristics of different germanate glasses have been invistgated. • All glasses were studied using XCOM program at several photon energies between 0.015 and 10 MeV. • The HVL results for the present germanate glasses suggested that the gamma photons absorption capacity increases as the density of the sample increases. • The result of different parameters suggested that to enhance the photon absorption ability for the germanate glasses, high Z -elements (such as Bi, Te and Tb) in a suitable concentration must be considered. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we studied the gamma photon attenuation properties for different germanate glasses systems with composition Sb 2 O 3 –GeO 2 –SiO 2 –Al 2 O 3 , TeO 2 –WO 3 –GeO 2 , GeO 2 –TeO 2 /SiO 2 –PbO–CaO–Tm 2 O 3 and B 2 O 3 –GeO 2 –Gd 2 O 3 –Eu 2 O 3 –GdF 3 –BaF 2. The mass attenuation coefficients (μ/ρ) for the selected germanate glasses were calculated at different energies (between 0.015 MeV and 15 MeV) using the MCNPX code. The calculated MCNPX μ/ρ values then compared with the WinXCom data to check the accuracy in the results. The results showed that the Sb 2 O 3 replacement by SiO 2 causes a decrease in μ/ρ for Sb 2 O 3 –GeO 2 –SiO 2 –Al 2 O 3 glass system. Also, it is found that for TeO 2 –WO 3 –GeO 2 glass system, μ/ρ decreases as GeO2 content increases from 1 to 20 mol%. While for GeO 2 –TeO 2 /SiO 2 –PbO–CaO–Tm 2 O 3 glass system, the results revealed that the glass samples contain TeO 2 possess higher μ/ρ values than the samples contain SiO 2. For the B 2 O 3 –GeO 2 –Gd 2 O 3 –Eu 2 O 3 –GdF 3 –BaF 2 glasses, we found that the μ/ρ values decrease as BaF 2 is increased from 0 to 15 mol%. Moreover, it is found that 50Sb-0Ge for series 1, TWG0 for series 2, 2G4T for series 3 and X = 0 for series 4 glass samples among the studied glasses have the highest effective atomic number values. On the basis of the results achieved, 50Sb-0Ge, TWG0, 2G4T and X = 0 samples have the best radiation shielding characteristics among the selected glasses. Highlights • Radiation shielding characteristics of different germanate glasses have been investigated. • The μ/ρ for the selected germanate glasses was evaluated by MCNPX simulation code at different energies. • The HVL results for the present germanate glasses suggested that the gamma photons absorption capacity increases as the density of the sample increases. [ABSTRACT FROM AUTHOR]

Abstract Raman and infrared spectroscopy were used to determine the structure of glasses for compositions хK 2 O-(100-х)GeO 2 , where х = 0, 10, 20, 30 и 40 mol%. Curve-fitting was applied to both medium- and high-frequency regions of the Raman spectra, and the main structural species formed in the system were defined. It was shown that the maximum of Ge(IV) → Ge(VI) conversion occurs at a composition of about 20 mol% K 2 O. A further increase of modifier cation in glasses results in a decrease in the coordination number of Ge atoms. At the same time, there is a depolymerisation of the three-dimensional disordered network and formation of tetrahedra [GeO 4 ] with one and two non-bridging oxygen atoms. [ABSTRACT FROM AUTHOR]

Highlights • 2.0 μm emission is obtained in Tm3+/Ho3+ codoped silicate-germanate glass. • Energy transfer is analyzed when pumped by conventional 808 nm LD. • Present glass possesses good thermal stability and transition probability. • Tm3+/Ho3+ codoped silicate-germanate glass is a good candidate for broadband 2.0 μm laser. Abstract The Tm3+/Ho3+ co-doped silicate-germanate glasses with good thermal properties were synthesized by high temperature melting method. 2.0 μm emissions with broad effective half-width (231.5 nm) were successfully obtained in present Tm3+/Ho3+ co-doped glasses without obvious quenching upon excitation of a commercial 808 nm laser diode. To further understand 2 μm fluorescence behaviors of the prepared glasses, energy transfer mechanism, efficiency, rate and microparameters from different levels of Tm3+ to Ho3+ ions have been obtained and discussed. In short, the Tm3+/Ho3+ co-doped silicate-germanate glass with excellent spectroscopic properties might be an attractive host material for 2 μm broadband solid laser. [ABSTRACT FROM AUTHOR]

Abstract Er3+-doped oxyfluoride germanate glass containing LaF 3 nanocrystals have been prepared via heat treatment from the precursor glass. Dynamic and static spectroscopic characteristics of IR, MIR and upconversion fluorescence of Er3+ doped transparent oxyfluoride germanate glass ceramic were investigated. When heat treat temperature increased from 540 to 600 °C, NIR and MIR fluorescence intensity increase about 3 times, and companied with 2060 times 550 nm and 350 times 660 fluorescence enhancement. Increasing the heat treat time at 560 °C from 2 to 12 h, the NIR and MIR fluorescence intensity increased about 2.5 and 1.8 times. It was due to the part of Er3+ ions were incorporated into LaF 3 nanocrystals, resulting in the decrease of the multi-phonon relaxation of Er3+. According to the ratio between MIR fluorescence intensity of the heat treated glass sample to that of the untreated glass sample, the number of the Er3+ which was incorporated into the LaF 3 nanocrystals can be quantificationally estimated. It was estimated to be 0.98%–5.8% when the heat treat temperature increased from 540 to 600 °C, and 1.21%–1.63% with increasing heat treat time from 2 to 12 h. Highlights • High transparence Er3+ doped germanate glass containing LaF 3 nanocrystals were successfully fabricated by the one step heat treating. • About 2000 and 3 times enhancement for upconversion, NIR, MIR fluorescence were observed from germanate glass containing LaF 3 nanocrystals. • A method to quantificationally estimate the number of the Er3+ which was incorporated into the LaF 3 nanocrystals was proposed. [ABSTRACT FROM AUTHOR]

Abstract The interaction of Ge 9 As 9 Se 82 and Ge 16 As 24 Se 60 amorphous chalcogenide thin films with electron beam has been investigated. The kinetics of surface relief formation was determined for both film compositions. It was established that for identical electron beam irradiation parameters, the kinetics of relief formation can be correlated with charge accumulation rate, its final value inside films and charge diffusion away from the electron interaction region. Charge model has been used to explain various phenomena during electron beam interaction with studied systems and parameters of this model are determined. Application of studied systems in single stage electron beam lithography is also presented. Highlights • We studied kinetics of e-beam interaction with amorphous chalcogenide glass films. • We observe formation of various structures on the film surface. • Shape of the structure can be controlled by the dose. • We can tune sensitivity of thin film to e-beam by changing film conductivity. • Charge removal/accumulation plays role in relief formation during e-beam deposition. [ABSTRACT FROM AUTHOR]

Abstract The structural, thermal, and luminescent properties of germanate glass containing heavily Dy 2 O 3 content are systematically investigated by means of differential scanning calorimetry, X-ray diffraction, Raman spectra, absorption and emission spectra, and dynamic lifetime decay curves. To seek a suitable composition, the optimal glass forming region is first predicted through the thermodynamic calculation method and their basic physical properties are further forecasted according to the phase diagram model. The experiment results show that the density, refractive index, characteristic temperature, and phonon energy of the glass host all exhibit a close connection with the rare earth concentration. Strikingly, when the amount of Dy 2 O 3 is up to 10.5 mol%, the transition temperature of the glass reaches 747 °C, which is higher than any other known germanate glass and is much advantageous to achieve a higher laser damage threshold. Moreover, the high doping caused the refractive index to increase significantly, which also prompted the glass to obtain a larger emission section and quality factor, increasing the possibility of laser output. Besides, three visible luminescence peaks of Dy3+ at 480 nm (blue) and 575 nm (yellow), and 665 nm (red) are observed even at an extremely high Dy3+ concentration. All the results demonstrate that this kind of germanate glass containing significant amounts of RE could be of interest for implementation of high-gain fiber lasers. Highlights • Heavily Dy 2 O 3 content germanate glass were investigated. • Glass-forming regions of the glasses were predicted via the thermodynamic method. • The calculated and experimental glass-forming regions were studied. [ABSTRACT FROM AUTHOR]

Abstract Germanosilicate glasses are essential in the manufacture of optical amplifiers, waveguides, and solid-state lasers. ZnO, with a wide direct band gap of 3.37 eV, has a broad range of applications in UV-shielding materials. To the best of our knowledge, no previous research adding ZnO into germanosilicate glasses has been reported. In this study, thirteen samples centered around a molar composition of 20K 2 O-20ZnO-40GeO 2 -20SiO 2 were melted, and the composition-property relationships were investigated. The densities are in the range of 3.18–3.46 g/cm3 and the refractive index values (RI) are between 1.588 and 1.630, close to the RI of pure GeO 2 (1.603). Density and RI values increase with GeO 2 and SiO 2 concentrations. The UV cut-off edge is between 313 and 320 nm, significantly higher than the 157 nm value in typical soda lime glass. Fragility (m) and glass transition temperature (T g) were determined by fitting viscosity data with the MYEGA equation. The T g from the MYEGA equation is in good agreement with T g values from DSC. Thermal expansion coefficient of samples is in the range of 102.7 to 139.2 × 10−7/°C, mainly influenced by the amount of ZnO and K 2 O. We conclude that these samples have relatively high refractive index, high transparency, good glass forming ability, and good UV-shielding properties, making them suitable for lens applications. [ABSTRACT FROM AUTHOR]

Abstract Glasses of Ge 25- x Ga x Te 75- y I y system with gallium content of 5–15 at.% and iodine of 0–6 at.% have been prepared. The glass transition temperature, crystallization and melting temperature of the samples in the range 100–400 °C were determined by differential scanning calorimetry. In Ge 15 Ga 10 Te 75- y I y system, the crystallization stability of glasses is extremely dependent on composition, taking the maximum value for y = 2; for Ge 10 Ga 15 Te 75- y I y and Ge 25- x Ga x Te 69 I 6 systems, a monotonous increase in the resistance to crystallization with an increase in the content of iodine and gallium is characteristic. The density of the glasses, measured by the hydrostatic weighing method, decreases with increasing of y. In view of physicochemical and optical properties among the investigated samples, the glasses of Ge 15 Ga 10 Te 73 I 2 and Ge 10 Ga 15 Te 69 I 6 are the most suitable for drawing optical fiber. Optical fibers are manufactured from these glasses by crucible method. Highlights • In Ge 15 Ga 10 Te 75- y I y system, the crystallization stability of glasses is extremely dependent on composition, taking the maximum value for y = 2; • For Ge 10 Ga 15 Te 75- y I y system a monotonous increase in the resistance to crystallization with an increase in the content of I is characteristic. • The glasses of Ge 15 Ga 10 Te 73 I 2 and Ge 10 Ga 15 Te 69 I 6 are the most suitable for drawing optical fiber. [ABSTRACT FROM AUTHOR]

Abstract The present investigation explores the adaptability of the lead-germanate network with the Ag 2 O content in the system with xAg 2 O·(100-x)[7GeO 2 ·3PbO 2 ] composition where x = 0–40mol% Ag 2 O. All obtained glasses have amorphous structure. The existence of crystallite particles with different morphologies in studied glasses was confirmed by the Scanning Electron Microscopic (SEM) and the Small Angle Neutron Scattering (SANS) investigations. Our IR and Raman data show that by increasing the Ag 2 O content of samples up to 15mol%, the [GeO 4 ] tetrahedral structural units were converted in [GeO 6 ] octahedral structural units and an increase in the polymerization visibly of the glass network was observed. In this manner the excess oxygen atoms added to the host matrix through modifier oxides are taken up by transforming of lead-germanate network to silver-lead-germanate glassy network. Some silver atoms will be implied in the compensation of the excess of negative electric charge and another are taken up by forming of Ag-O bonds. The analysis of quantum chemical calculations on the local structure of the 40Ag 2 O·60[7GeO 2 ·3PbO 2 ] network suggest the presence of deformed higher-fold coordinated polyhedrons of the lead and germanium atoms (n = 4 and 6) and the sites of the silver of ionic and covalent nature. Structural parameters determined from SANS data reveal that the size of the particles varies from 36 to 58 Å and nanoheterogeneities are essentially monodisperse. Highlights • The breaking of Ge-O-Ge linkages and bending of Pb-O-Pb linkages. • The decrease of gap energy. • Deformed higher-fold coordinated polyhedrons of the lead and germanium atoms. • The sites of the silver of ionic and covalent nature. [ABSTRACT FROM AUTHOR]

Abstract Er3+-doped and Er3+/Yb3+-codoped GeO 2 -Nb 2 O 5 -K 2 O glasses were prepared by conventional melt-quenching method. Thermal and spectroscopic analysis were performed. The niobium insertion into the glass structure has decreased the OH groups resulting in a slight increase in the luminescence efficiency as the niobium content. Glass network structure is modified depending on rare earth doping concentration and niobium content. The number of bridge oxygen bonds and nonbridge oxygen bonds is altered and consequently the crystallization composition. The spectroscopic features were discussed in terms of niobium concentration and its influence on the applications as optical devices. The addition of niobium broadens the emission band in the region of 1.5 µm covering C, S and L-telecommunication bands. The gain coefficient has calculated establishing high potentiality to use the niobium germanate glasses for optical amplification. The codoping by Er3+/Yb3+ intensifies the emission in the NIR and visible (upconversion) region in relation to the doped samples and may be interesting for application as visible and near-infrared emitters. In addition, the codoped samples with variable niobium contents have potential as visible tunable phosphors emitting either green or red light. Accordingly, the niobium germanate glasses are interesting matrices for rare earth ions doping and for the development of optical devices, such as visible and NIR laser and optical amplifiers. [ABSTRACT FROM AUTHOR]

Abstract Fully amorphous rare earth co-doped barium gallo-germanate glasses were synthesized using the traditional melt quenching-technique. The glass systems were doped with selected pairs of rare earths Dy3+/Ce3+ and Dy3+/Tm3+ ions. To study the spectroscopic properties of gallo-germanate glasses co-doped with Dy3+ and Ln3+ (Ln = Ce, Tm) ions, the luminescence spectra and luminescence decay curves were recorded. It was observed that luminescence bands corresponding to characteristic transitions of Ln3+ (Ln = Ce, Tm) and dysprosium ions are present in the emission spectra measured under direct excitation of Ln3+. The experimental results indicate that energy transfer between dysprosium and cerium/thulium ions is effective. From the emission spectra, the Commission Internationale de I'Eclairage (CIE) chromaticity coordinates (x, y) were calculated in relation to the potential application of gallo-germanate glasses for white LEDs. It has been proved that our glass systems exhibit white emission originating from the simultaneous generation of several bands of Dy3+, Ce3+/Tm3+ under the UV-visible light excitation. Highlights • The rare earth co-doped barium gallo-germanate glasses were synthesized. • The luminescence spectra and luminescence decay curves were registered. • The energy transfer between dysprosium and cerium/thulium ions was examined. • The glass systems exhibit white emission under the UV-visible light excitation. [ABSTRACT FROM AUTHOR]

Abstract A series of Sr 3 La 2- x Eu x (Ge 3 O 9) 2 (x = 0.1–1.8) cyclogermanates has been prepared by the citrate method. The powder XRD study has shown that the compounds crystallize in the monoclinic space group C 2/ c , Z = 4. An increase in the dopant content causes a morphotropic phase transition: at x = 0.1–0.7 the samples are isostructural to Sr 3 La 2 (Ge 3 O 9) 2 , while at x = 0.9–1.8 the germanates have a crystal structure of Sr 3 Eu 2 (Ge 3 O 9) 2. In all compounds, strontium and rare earth ions occupy three symmetry independent cation sites and form layers alternating along the [ 1 0 1 ¯ ] direction. The relationships between the crystal structure and the luminescence characteristics: the energy of the charge transfer transition, the values of 4 f –4 f /CTB and 5D 0 → 7F 2 /5D 0 → 7F 1 intensity ratios have been revealed. CIE chromaticity coordinates for Sr 3 La 1.4 Eu 0.6 (Ge 3 O 9) 2 and Sr 3 La 0.8 Eu 1.2 (Ge 3 O 9) 2 phosphors under 393 nm excitation have been measured. Graphical abstract The crystal structure and photoluminescence spectra of Sr 3 La 1.3 Eu 0.7 (Ge 3 O 9) 2. Image 1 Highlights • The novel red emitting phosphors based on Sr 3 La 2- x Eu x (Ge 3 O 9) 2 have been prepared • Effect of crystal structure on the luminescence properties of Sr 3 La 2- x Eu x (Ge 3 O 9) 2 phosphors has been studied • Optimal dopant concentration has been determined [ABSTRACT FROM AUTHOR]

• The properties and uses of several types of glass and microcrystalline glass as anodes were discussed, including tin oxide glass, vanadium oxide glass, and other germanium oxide glass and iron oxide glass. • The usage of glassy MOF materials to overcome MOF material volume change during charge and discharge, as well as the order and disorder transition of certain MOF materials during charge and discharge were introduced. • The use of vanadium-based glass as cathode material was discussed. • The application of glass, especially sulfide glass, as an all-solid-state battery electrolyte and the effect of mixed anion effect on improving the conductivity of solid electrolytes were introduced. Due to its distinct network structure, lack of a grain boundary, and isotropic qualities, glass has been the subject of extensive research. Lithium ion batteries can have their capacity and safety increased by using glassy electrode and electrolyte materials. We discuss the properties and uses of several types of glass and glass ceramic as anodes, including tin oxide glass, vanadium oxide glass, and so on. Metal-organic framework (MOF) materials are also investigated as a new generation of high-performance anode materials. We present the usage of glassy MOF materials to overcome MOF material volume change during charge and discharge, as well as the order and disorder transition of certain MOF materials during charge and discharge. The use of vanadium-based glass as a cathode material is also discussed. These materials have the potential to be employed as electrode materials in the next generation of lithium- ion batteries. In addition, the application of glass, especially sulfide glass, as an all-solid-state battery electrolyte and the effect of mixed anion effect on improving the conductivity of solid electrolyte were introduced. [ABSTRACT FROM AUTHOR]