Germanate-tellurite Glass Research Articles

Excellent Color Purity and Luminescence Thermometry Performance in Germanate Tellurite Glass Doped with Eu3+ and Tb3+

Germanate tellurite glasses doped with Eu3+ and Tb3+ were synthesized by the conventional melt-quenching method. There is no indication of the energy transfer between dopant ions in this host, but the co-dopants exhibit excellent color purity of 100% for Eu3+ and 80% for Tb3+. The co-doped glass exhibits yellow luminescence. The quantum yield of the Eu3+ emission is equal to 23% under 395 nm excitation. The thermal quenching of Eu3+ and Tb3+ luminescence occurs at different temperature ranges, which enables the thermal sensing properties of the material. The relative fluorescence intensity ratio (FIR) sensitivity of 0.16% K−1 was recorded in the wide range of temperatures spanning from −193 °C up to 0 °C. The temperature dependence of the decay times was also studied. The lifetime-based temperature sensitivity was determined to be 0.95% K−1 at 250 °C for Tb3+5D3 level emission and 0.3% K−1 at 225 °C for Eu3+5D1 level emission.

Efficient green upconversion emission in transparent Teo2-Geo2 glass-ceramic obtained by billet extrusion

Transparent Yb3+/Er3+glass-ceramic was successfully obtained by the extrusion method. The extrusion of oxyfluoride tellurite-germanate glass co-doped with Yb3+and Er3+ions at 520°C resulted in the formation of Ba0:75Er0:25F2:25 nanocrystals, leading to an increase in the upconversion (UC) emission intensity of 35 times in glass-ceramic with respect to the glass. The glass to glass-ceramic transition was confirmed by X-ray diffraction (XRD) and Transmission electron microscope (TEM). Also, the structural changes that occurred during crystallization were assessed using Fourier-transform infrared (FTIR) spectroscopy. Furthermore, the pump power and temperature UC emission dependence of glass and glass-ceramic under 976 nm laser excitation were investigated in detail. The assessments showed that i) two-phonons are involved in the UC process and ii) the temperature has a significant influence over it. The Yb3+/Er3+ codoped glass-ceramic shows relatively high Sa and Sr values in a wide temperature range from 300 to 573 K, presenting the maximal Sa value of 3:50 x 10–3 at 573 K and the maximal Sr value of 6:30 x 10–3at 364 K. These results suggest that the glass-ceramic is a good candidate for optical applications such as luminescent thermometry.

Structural, luminescence, and temperature sensing properties of the Er3+-doped germanate-tellurite glass by excitation at different wavelengths

Er3+-doped germanate-tellurite glasses were prepared by high-temperature melting method, in which structure, luminescent and, temperature-sensing properties were studied. The Raman spectrum indicates that the maximum phonon energy is low, which is 860 cm−1. The transmission spectrum indicates that the infrared transmissive range of glass is wide, visible, and infrared transmittance is high. Parameters of spectral line intensity Ωλ and radiation parameters were calculated based on Judd-Ofelt theory, which showed that the glass has large values of Ω2 and Ω6, and values of Ω2 and Ω6 decrease with increasing concentration of Er3+ ions. Strong up-conversion luminescence was obtained at 808, 980 and 1550 nmLD with wavelengths at 534, 553 and 668 nm, respectively, and strong down-conversion luminescence of 1.53 and 2.7 μm also were obtained. The up-conversion emission intensity under three-wavelength simultaneous excitation is significantly enhanced compared to monochromatic excitation. The emission intensity corresponding to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transition of Er3+ ions varied with temperature, and the fluorescence intensity ratio FIR of 556 nm and 524 nm increased with increasing temperature. In the temperature range from 330 to 610 K, the maximum sensitivity of glasses was 15.63 × 10−3 K−1 and 19.74 × 10−3 K−1 at T = 570 K, respectively under 808 and 980 nm LD excitation.

Phase regulation of Cs4PbBr6/CsPbBr3 in tellurate germanate glasses induced by P2O5

All inorganic perovskite quantum dots (QDs) have broad applications due to its unique photoelectric properties. At present, a large number of QDs embed glasses of three-dimensional (3-D) CsPbBr3 cubic phase or zero dimensional (0-D) Cs4PbBr6 hexagonal phase have been reported, but the phase regulation between 0-D and 3-D has not been deeply studied only by the adjustment of the glass network topology. In this paper, Cs4PbBr6/CsPbBr3 QDs were successfully synthesized in tellurite germanate glass by high-temperature melt-quenching combined with in-situ crystallization, and their luminescence properties, structures, and phase regulation fundamentals in glasses were investigated in depth. The introduction of P2O5 increases the ratio of [TeO4]/[TeO3] units in the tellurite germanate glasses, resulting in a more compact glass network and changing the growth environment of QDs. When the content of the nucleating agent P2O5 was increased to 3% (mass fraction), the crystalline phase of QDs realized the regulate from 0-D hexagonal phase to 3-D cubic phase. The regulation from Cs4PbBr6 to CsPbBr3 is accompanied by a blue-shifted emission peak from 519 to 482 nm, and the synthesized QDs glasses all have good long-term stability. The QDs glasses obtained in the experiment has great potential in the application of white light emitting diodes.

Towards obtaining the optimum physical, optical and nuclear radiation attenuation behaviours of tellurite–germanate glasses through Eu2O3 reinforcement: Glass synthesis, experimental and theoretical characterisation study

We report the physical, optical and nuclear radiation attenuation behaviours of tellurite–germanate (TeO2–GeO2–PbO) glasses reinforced with varying amounts of Eu2O3. The samples were synthesised using the conventional melt-quenching method and had the following composition (in wt.%): 33.34TeO2 - 33.33GeO2 - 33.33PbO (TGP). Different concentrations of Eu2O3 (in wt.%) were added to the glass composition, labelled TGP1, TGP2 and TGP3. The physical, optical and nuclear radiation attenuation properties were measured using both experimental and theoretical methods. At room temperature, the visible to near-infrared optical absorption spectrum ranged from 400 to 900 nm. The TGP1 sample with 1 wt% The Eu2O3 additive exhibited the lowest absorbance and the highest transparency. The TGP1 sample also exhibited the highest nuclear radiation absorption properties. The gamma-ray absorption capabilities of TGP1 were demonstrably superior to those of various types of glass shields and other old- and new-generation concrete-shielding materials. Thus, adding 1 wt% Eu2O3 to tellurite–germanate glasses would ‘improve nuclear radiation absorption and optical properties. It can also be concluded that expanded scientific community investigations in this area would be a significant step toward gaining a deeper understanding of these glass structures and determining what other optimisation tasks the addition of 1 wt% Eu2O3 can accomplish.

Design of the YAG:Ce3+ phosphor in tellurite-germanate glass with high luminous efficiency for laser lighting

The main focus of laser lighting research has been on perfectly combining fluorescent conversion materials with laser light sources to improve luminous efficiency (LE). In this paper, the high refractive index, high transmittance and low sintering temperature of tellurite glass is combined with the thermal stability and mechanical strength of germanate glass，which is innovatively used as a matrix for phosphor-in-glass (PiG). The use of high valent ions as modifiers reduces the diffusion and mobility of ions to reduce the erosion of phosphors and protect the luminescent performance of phosphors. By changing Ge/Te ratio, the glass maintains 80% transmittance, and the refractive index decreases from 1.97 to 1.83 matching that of the YAG phosphor. The increase in GeO2 improves the thermal stability and mechanical strength of the glass, thereby improving the fluorescence intensity (approximately 1.6%) at 473 K and the luminous flux by up to 12.8%. The best PiG sample had a LE of 230 lm/W and excellent internal quantum efficiency (IQE) of 85.3%, achieving high levels of luminescence. Adding different phosphor contents can achieve the role of adjusting the correlated color temperature (4500–6000 K), and the color coordinates (0.322, 0.330) are close to the ideal white light. These results show that tellurite-germanate glass can be used as a good carrier for fluorescence conversion materials, which brings a new direction for the exploration of glass matrix.

Oxyfluoride germanatetellurite glasses doped with dysprosium—Spectroscopic characteristic and luminescence thermometry qualities

Germanatetellurite glasses doped with different concentrations of dysprosium were manufactured and studied utilizing various optical spectroscopy techniques. Radiative transition rates, branching ratio of luminescence and radiative 4F9/2 lifetime were estimated for material under study. The impact of the glass host and the incorporation of luminescent ions on the temperature-dependent absorption and luminescence characteristics were investigated in a temperature range of 300–675K. Detailed analysis of the absorption spectra showed that efficiency of the UV Dy3+ excitation can be significantly reduced especially at higher temperatures. Fluorescence intensity ratio (FIR) between thermally-coupled 4I15/2/4F9/2 multiplets gradually increased with temperature rinsing and eventually, absolute and relative sensitivities were estimated. The effective Dy-Dy interactions take place in the studied germanatetellurite glasses and critical radius R0 was found to be 5.8Å. It was revealed that near infrared femtosecond pulses can be converted on blue and yellow dysprosium luminescence as result of up-conversion phenomena in the examined oxyfluoride glass.

TeO2-GeO2-BaF2-Tm2O3 glass for ∼2 μm laser materials: Analysis of luminescence features and energy transfer behavior

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% Tm2O3, 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.

Mechanical property evaluation of tellurite–germanate glasses and comparison of their radiation-shielding characteristics using EPICS2017 to other glass systems

Abstract In this study, four tellurite–germanate glasses containing zinc, lithium, and bismuth with varied Bi2O3 and TeO2 amounts were investigated. The mechanical qualities of sample glasses were investigated and associated with their structural properties. Furthermore, the radiation-shielding capabilities of N1–N4 glasses were evaluated at 0.662 MeV using EPICS2017. The radiation-shielding characteristics were compared with the radiation-shielding parameters published in the literature for various glass systems. When TeO2 was replaced with Bi2O3, Young’s and bulk moduli of the material decreased. The L values of glasses were higher than their S values (14–13 GPa), indicating that they can tolerate longitudinal stress better than shear stress and can be bent rather than elongated readily. The MACs calculated were comparable to those obtained using WinXcom. The tenth-value layer (TVL) of all of the sample glasses was higher than that of the bismuth aluminosilicate glasses. All of the borate glass systems containing bismuth, sodium, and antimony had lower TVLs than N1–N3 glasses. The half-value layer was more in the N4 glass with the greatest Bi2O3 content than those in 50 and 60 mol% PbO-containing strontium borate glasses.

Color Tunable Emission of Y3Al5O12:Ce3+ and Sm3+‐Doped Zinc–Germanate–Tellurite Glass Nanocomposite Powders and Coatings for Light‐Emitting Diodes Applications

A series of nanocomposite (NC) powders and coatings of ZnO–GeO2–TeO2:xSm3+ glass and Y3Al5O12:Ce3+ nanoparticles (YAG:Ce) are fabricated. Samarium ions concentration of the glass phosphor is varied with x values of 0.3, 1.0, 3.0, and 5.0 mol%. The powder batches are prepared with a 95/5 mass ratio of glass/YAG:Ce and uniaxially pressed to obtain powder pellets that are heat‐treated at 350 °C. Morphology and structural characterization are conducted through X‐ray diffraction analysis, scanning electron microscopy, and Raman spectroscopy. The photoluminescence properties of NCs are investigated under different wavelengths of 340, 403, and 460 nm, showing a global emission tonality in the reddish‐orange and yellowish‐green region according to the estimated CIE 1931 chromaticity coordinates. Also, NC coatings soda–lime glass slides are fabricated, and their photoluminescence is characterized using an UV light‐emitting chip (≈365 nm) and a blue light‐emitting chip (≈460 nm). The global emission under UV and blue light from the light‐emitting diode (LED) chips of the NC coatings shows a color tunability in the warm white light and yellowish‐green region.

The fabrication of nanodiamond doped tellurite germanate glass with robust structure and its luminescence

AbstractFluorescence of negative‐charged nitrogen‐vacancy centers in nanodiamond allows applications in quantum metrology, nanoscale sensor, and bioimaging, of utmost relevance to domains from nanotechnologies to biosensing. However, the low color center content and collection efficiency of photons are crucial issues. Although, several studies about coupling nanodiamond into optical waveguides have already been proposed, the search for the most appropriate substance and simplest, most effective method are of keys. In this study, we present a novel nontraditional way to incorporate nanodiamond with increased negative‐charged nitrogen‐vacancy content to 75.48% into tellurite germanate glass. The hybrid glass is stable in structure with predominant TeO4 trigonal bipyramid. Moreover, the fluorescence intensity is enhanced in composite. Such robust nanodiamond in tellurite germanate glass optical system has the potential to be used for nanoparticle sensing and quantum metrology.

Luminescence and study of channels for cross-relaxation dependent on the concentration of Sm3+ under simultaneous UV-IR excitation in tellurite-germanate glasses

A spectroscopic evaluation of Sm3+ doped TeO2-GeO2-ZnO glasses (0.5, 1.0, 3.0 and 5.0%) was carried with aim to determinate the dominant process in the cross-relaxation mechanism at high and low concentrations of Sm3. A new experimental spectroscopic technique is proposed, based on the analysis of the time evolution of the 600 m emission, corresponding to the 4G5/2 → 6H7/2 transition, obtained under spatial and temporal simultaneous excitation at 355 nm and into the infrared (950, 1085 1236, 1380 nm). It was possible to determine that at low Sm3+ content the dominant channel for cross relaxation is 4G5/2 + 6H5/2 → 6F5/2 + 6F11/2 and at high concentrations are: 4G5/2 + 6H5/2 → 6F7/2 + 6F9/2, 4G5/2 + 6H5/2 → 6F9/2 + 6F7/2, 4G5/2 + 6H5/2 → 6F11/2 + 6F5/2, and the least contributor one being 4G5/2 + 6H5/2 → 6F5/2 + 6F11/2. It is reported the optical absorption and Raman spectroscopies, photoluminescence spectra and decay time profiles as a function of Sm3+ concentration. Emission spectra measurements indicated that concentration quenching is active in the samples, being 1.0 mol% the optimum concentration for luminescence of Sm3+ ions. The decay time of 4G5/2 level upon 403 nm excitation, at 0.5% of Sm3+, presents a decay curve single exponential, however, when the concentration increases, the time decay reduces and becomes non-exponential. The Inokuti-Hirayama model was used to infer that an electric dipole-dipole mechanism is the dominant interaction in the energy transfer process between Sm3+-Sm3+ ions.

Physical, structural, optical and gamma radiation attenuation properties of germanate-tellurite glasses for shielding applications

Germanate-tellurite glasses with a composition of (75-x) TeO2-xGeO2–12.5ZnO-12.5BaO, where x = 0, 5, 10, and 20 mol%, were synthesized. A traditional melt-quenching-annealing process was used to fabricate these glasses, at 1000 °C for melting and 300 °C for five hours for annealing. X-ray diffraction was used to investigate the structural features of each sample between 10 °C and 80 °C to prove the amorphous nature of these glasses. Moreover, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) was employed to explore the functional groups of Te, Ge, and other elements. To study the transparency, cut-off wavelength, and other optical properties of the glasses, such as indirect, direct, and Urbach energy band gaps, optical absorption was measured in the range of 200–800 nm. Additionally, the radiation shielding properties for the germanium based-tellurite glasses were calculated using Monte Carlo N particle transport code (MCNP-5). The simulated results were compared with XCOM software and the results between the two methods closely agreed. The maximum mass attenuation coefficient varied between 47.305 and 50.620 cm2.g − 1 for TG1 and TG4 glasses respectively at 0.015 MeV. The effective atomic number (Zeff) for the prepared germanium based-tellurite glasses was evaluated and the results revealed that the maximum Zeff values were found at 0.04 MeV, varying between 48.24 and 49.98 for TG4 and TG1.

Ionizing radiation attenuation competences of gallium germanate-tellurite glasses utilizing MCNP5 simulation code and Phy-X/PSD program

Gamma radiation, neutrons, protons, and alphas particles shielding competences for gallium germanate-tellurite (GeO2.TeO2.Ga2O3) glasses doped with Pr6O11 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 (Zeff) 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 Zeff 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 (ΣR = 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.

掺铥钬离子碲锗酸盐玻璃2 μm发光性能研究

掺铥钬离子碲锗酸盐玻璃2 μm发光性能研究

2.0-µm and 4.1-µm mid-infrared broadband emission enhancement in Ho3+/Yb3+ co-doped tellurite–germanate glasses

Ho3+/Yb3+ co-doped tellurite–germanate glasses with lower phonon energy (771 cm−1) were prepared by conventional melt-quenching method. The prepared samples were characterized by emission spectra, differential scanning calorimeter (DSC) curve, X-ray diffraction (XRD) pattern, and Raman spectra. The DSC curve shows that the sample has a good thermal stability, in which the ΔT is 202 °C. Compared to the recently reported tellurite glasses, the ΔT was increased by approximately 24%. Under the 980 nm laser excitation, it was found that the full width at half maximum (FWHM) of the sample at 2.0 µm was 190 nm. Compared with the reported glasses for this type, the value was effectively improved. Meanwhile, the FWHM of the sample at 4.1 µm was 285 nm, which has not been reported yet. This indicates that Ho3+/Yb3+ co-doped tellurite–germanate glass has a great application prospect in mid-infrared broadband fiber amplifiers.

Broadband mid-infrared 2.0 μm and 4.1 μm emission in Ho3+/Yb3+ co-doped tellurite-germanate glasses

Ho3+/Yb3+ co-doped tellurite-germanate glasses with lower phonon energy (779 cm−1) and higher thermal stability were prepared by conventional melt quenching. The mid-infrared fluorescence spectra of the prepared glasses were investigated by 980 nm laser pumping. The full width at half maximum (FWHM) and lifetime of the sample at 2.0 μm were 186 nm and 8.09 ms, respectively. Compared with the reported glasses for this type, these values were effectively improved. In particular, the FWHM and emission lifetime of the prepared glass at 4.1 μm reached 276 nm and 8.17 ms, respectively, which have not been reported yet. Meanwhile, compared to the recently reported tellurite glasses, the ΔT was increased by approximate 22.7%. Strong up-conversion visible emission peaks at 547, 662, and 756 nm and near-infrared emission at 1.20 μm were observed in Ho3+/Yb3+ co-doped glass. Meanwhile, photoluminescence measurements showed that the doping of the appropriate amount of Yb3+ ions significantly enhanced the emission intensity of the samples at 2.0 μm and 4.1 μm. Therefore, the Ho3+/Yb3+ co-doped tellurite-germanate glass is a promising candidate for mid-infrared fiber and laser materials applications.

Structural, optical, and shielding investigations of TeO2–GeO2–ZnO–Li2O–Bi2O3 glass system for radiation protection applications

Glass gained much attention to be utilized in various applications, for this reason different kinds of glass compositions was the subject of investigation. In this work, we successfully fabricated a series of tellurite–germanate glasses with a composition of (70-x)TeO2–10GeO2–10ZnO–10Li2O–xBi2O3, where x = 0, 5, 10 and 15 (all in mol%). Ordinary melt-quenching was used to synthesize the mentioned glass series with 975 °C as a melting temperature for 30 min and 300 °C for annealing to release the internal stress. To study the structural properties of these glasses, X-ray diffraction (XRD) was used to confirm the glassy structure of these glasses. Regarding that, XRD profiles were recorded in ranges between 10° and 80° for all samples. Moreover, FTIR was employed to study the functional groups of all elements, which were used in the composition with the range of 4000–400 cm−1. Optical absorption was used to investigate the cutoff wavelength and optical band gap. Optical absorption was measured at the range of 200–800 nm. The variation of the attenuation properties for the tested tellurite–germanate glasses has been investigated using WinXcom software for photon energy ranges between 0.015 and 15 MeV. The examined attenuation properties include linear and mass attenuation coefficients, half value layer and mean free path, and effective atomic number of the radiation shielding glass. The present results suggest the utilization of the new prepared glass samples in radiation shielding applications.

Investigation of Tm3+/Yb3+ co-doped germanate–tellurite glasses for efficient 2 µm mid-infrared laser materials

The Tm3+/Yb3+ co-doped germanate–tellurite glasses with good thermal properties were prepared. Based on the absorption spectra and the Judd–Ofelt theory, the J–O intensity parameters (Ω t ), radiative transition probability (276.78 s− 1), fluorescence lifetime (3.89 ms), absorption and emission cross sections ( $${\sigma _{\text{e}}}$$ = 1.35 × 10− 20 cm2) were calculated. The ~ 2 µm mid-infrared emission resulting from the 3F4→3H6 transition of Tm3+ sensitized by Yb3+ was observed pumped by 980 nm LD. Besides, the energy transfer mechanism between Yb3+ and Tm3+ was thoroughly discussed. The measured ~ 2 µm emission lifetime of Tm3+/Yb3+ co-doped glass can reach as high as 2.38 ms. The above results showed that Tm3+/Yb3+ co-doping glass could be expected to be a promising material to achieve high efficient ~ 2 µm lasing with a 980 nm LD pumping.

Yellow to orange-reddish glass phosphors: Sm3+, Tb3+ and Sm3+/Tb3+ in zinc tellurite-germanate glasses

An optical spectroscopy analysis of TeO-GeO2-ZnO glass co-activating Sm3+/Tb3+ ions was carried out through Raman, photoluminescence spectra and decay time profiles as a function of Sm3+ concentration. According to the estimated CIE1931 chromaticity coordinates, the color of the emission can be adjusted from the yellow light region (0.4883, 0.4774), towards the reddish light region (0.5194,0.4144) by increasing the Sm3+ content from 1, 3, 5% mol, co-doped with 1% mol Tb3+ under co-excitation of Sm3+ and Tb3+ at 378 nm. The color temperatures are in the range of 1379–2804 K. Such photoluminescence is generated by the 4G 5/2 → 4H 5/2, 4H 7/2, 4H9/2 emissions of Sm3+ in addition to the 5D4→7F6,5,4,3 emissions of Tb3+; the single doped Sm3+ glass displayed an intense orange light. Meanwhile, co-doped Sm3+/Tb3+ glasses excited at 378 nm showed a significant reduction in Tb3+ emission, with a simultaneous increment in the reddish-orange emission of Sm3+, due to a non-radiative resonant energy transfer from Tb3+ to Sm3+. Decay time profile analysis of the Tb3+ emission as function of Sm3+ ion content suggests that an electric dipole–dipole interaction into Tb3+–Sm3+ clusters might dominate in the energy transfer process, with an efficiency and probability of 0.22, 0.27, 0.38 and 122.8, 327.6, 522.7 s−1, respectively.