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Effect of High Pressure in the Luminescence of Pr <sup>3+</sup> Doped Ge <sub/>2</sub> O- PbO Glass Containing Au Nanoparticles
摘要： In this paper it was investigated the combined effect of gold nanoparticles and high-pressure densification on the luminescence of Pr3+ doped heavy metal GeO2-PbO photonic glass. Localized states related to ion-trapped exciton defects, S1 and S2, were observed at 342 and 412 nm before densification. After densification under 7.7 GPa the structure of the glass host changed irreversibly, as indicated by the infrared spectrum, refractive index and density measurements. TEM analyses indicated that the high-pressure densification induced the formation of clusters of gold nanoparticles. The modifications observed in the absorption and luminescence spectra of Pr3+ ions in the VIS-NIR range were associated to the changes in the local field surrounding the Pr3+ ions in the host glass induced by high-pressure. For excitation at 445 nm (luminescence from 3P2) and 593 nm (luminescence from 1D2), the combined effect of densification and gold nanoparticles induced an increase in the emission band at 1050 cm-1. For excitation at 488 nm (luminescence from 3P0), the combined effect resulted in a strong decrease in the emission intensities in the VIS, revealing the emergence of non-radiative processes in resonance with 3P0 state. The observed behavior was probably due to energy transfer, ion trapped exciton defects and cross-relaxation processes among the Pr3+ ions and gold nanoparticles.
关键词： cross-relaxation processes,gold nanoparticles,Pr3+ doped,high-pressure densification,energy transfer,GeO2-PbO glass,luminescence
更新于2025-09-11 14:15:04
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An Investigation of Processes for Glass Micromachining
摘要： This paper presents processes for glass micromachining, including sandblast, wet etching, reactive ion etching (RIE), and glass reflow techniques. The advantages as well as disadvantages of each method are presented and discussed in light of the experiments. Sandblast and wet etching techniques are simple processes but face difficulties in small and high-aspect-ratio structures. A sandblasted 2 cm × 2 cm Tempax glass wafer with an etching depth of approximately 150 μm is demonstrated. The Tempax glass structure with an etching depth and sides of approximately 20 μm was observed via the wet etching process. The most important aspect of this work was to develop RIE and glass reflow techniques. The current challenges of these methods are addressed here. Deep Tempax glass pillars having a smooth surface, vertical shapes, and a high aspect ratio of 10 with 1-μm-diameter glass pillars, a 2-μm pitch, and a 10-μm etched depth were achieved via the RIE technique. Through-silicon wafer interconnects, embedded inside the Tempax glass, are successfully demonstrated via the glass reflow technique. Glass reflow into large cavities (larger than 100 μm), a micro-trench (0.8-μm wide trench), and a micro-capillary (1-μm diameter) are investigated. An additional optimization of process flow was performed for glass penetration into micro-scale patterns.
关键词： reactive ion etching,wet etching,sandblast,glass reflow process,glass micromachining
更新于2025-09-10 09:29:36
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Optimization of melting parameters and minimizing OH content in SiO <sub/>2</sub> -B <sub/>2</sub> O <sub/>3</sub> -Na <sub/>2</sub> O-BaO glass system in microwave heating
摘要： This study investigates the optimization of melting process for the glass comprising SiO2‐B2O3‐Na2O‐BaO under microwave (MW) heating. Batches were melted at different temperatures in the range of 900‐1250°C to optimize melting condition. X‐ray diffraction suggests amorphous nature of samples melted above 1150°C. Optimization of melting time was carried out by varying soaking time (8‐60 minutes) at 1250°C. UV‐Vis‐NIR spectra reveal ~90% transmission over 300‐2000 nm wavelength range for glass melted at 1250°C. Optical microscopic images suggest that the bubble‐free glass can be produced at 1250°C for 1 hour melting in MW heating. MW heating also helps in reducing OH content in glass. However, OH concentration is found to increase with melting time. OH content could be minimized to 68.56 ppm in glass employing oxygen atmosphere melting, which prevents OH diffusion from atmosphere into the melt. Residual stresses are estimated to be less in MW heating than conventional heating. Maximum MW power was observed to be 1 kW with a total electrical power consumption of around 5 kWh. Also, total time needed to prepare the glass is around 2 hours. Thus, MW heating could be an alternate efficient tool in producing low OH content glass.
关键词： boro silicate glass,dehydration method,OH reduction process,microwave heating,optimization of glass melting process
更新于2025-09-10 09:29:36
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Direct CVD Growth of Graphene on Traditional Glass: Methods and Mechanisms
摘要： Chemical vapor deposition (CVD) on catalytic metal surfaces is considered to be the most effective way to obtain large-area, high-quality graphene films. For practical applications, a transfer process from metal catalysts to target substrates (e.g., poly(ethylene terephthalate) (PET), glass, and SiO2/Si) is unavoidable and severely degrades the quality of graphene. In particular, the direct growth of graphene on glass can avoid the tedious transfer process and endow traditional glass with prominent electrical and thermal conductivities. Such a combination of graphene and glass creates a new type of glass, the so-called “super graphene glass,” which has attracted great interest from the viewpoints of both fundamental research and daily-life applications. In the last few years, great progress has been achieved in pursuit of this goal. Here, these growth methods as well as the specific growth mechanisms of graphene on glass surfaces are summarized. The typical techniques developed include direct thermal CVD growth, molten-bed CVD growth, metal-catalyst-assisted growth, and plasma-enhanced growth. Emphasis is placed on the strategy of growth corresponding to the different natures of glass substrates. A comprehensive understanding of graphene growth on nonmetal glass substrates and the latest status of “super graphene glass” production are provided.
关键词： super graphene glass,chemical vapor deposition,glass,graphene
更新于2025-09-10 09:29:36
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[Methods in Molecular Biology] Microfluidic Electrophoresis Volume 1906 (Methods and Protocols) || Fabrication of Glass Microfluidic Devices
摘要： This chapter provides step-by-step procedures for the fabrication of glass-based micro?uidic devices. These procedures include device design, photomask generation, photolithography, channel etching, and high-temperature bonding.
关键词： Glass bonding,Micro?uidics,Photolithography,Etching,Channel manifold
更新于2025-09-10 09:29:36
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Effects of TeO2 and CaCl2 network modifiers on the Er3+:4I11/2→4I13/2 transition in fluoroaluminate multi-component glasses
摘要： We investigated thermal and fluorescence properties of Er3+ doped fluoroaluminate multi-component glasses modified by TeO2 and CaCl2. A better thermal stability with a higher ΔT (98 °C) was obtained for the TeO2 modified sample, which had a high radiative transition probability (Arad) of the Er3+: 4I11/2→4I13/2 transition. In addition, under 980 or 808 nm excitation, the Er3+ 2.7 μm emission intensity of the TeO2 modified sample decreased owing to its increased hydroxyl content induced by TeO2 modifiers. Excellent mid-infrared fluorescence along with a longer lifetime (3.48 ms) were observed in the glass tuned by CaCl2. The CaCl2 modified sample exhibited higher stimulated absorption and emission cross sections, obtained using the Füchtbauer-Ladenburg and McCumber formulas. Moreover, the strong effect of hydroxyl on the mid-infrared fluorescence properties was systematically analyzed. The oxygen network modifiers in the fluoroaluminate multi-component glass provide improved thermal properties, while the AlF3-based glasses with chlorine network modifiers have larger potentials for applications in the mid-infrared region.
关键词： Er3+,CaCl2,fluoroaluminate glass,mid-infrared fluorescence,TeO2,thermal stability
更新于2025-09-10 09:29:36
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Investigation of luminescence mechanism of Nd3+-doped calcium aluminate glasses: Effect of glass-formers
摘要： The relationship between the luminescence properties and the glass structure of Nd3+-doped CaO-Al2O3-(B2O3, SiO2, or Ga2O3) glasses are investigated. The luminescence properties of CaO-Al2O3-B2O3 system are twice as much as that of the CaO-Al2O3-(SiO2 or Ga2O3) system. The glass structure and the coordination environment of the Nd3+ ions were investigated using nuclear magnetic resonance, Raman and electron paramagnetic resonance spectroscopy. All Al, Ga, and Si atoms are four coordinated. The B atoms have three- and four-coordinated boron units, however, most of them are three coordinated. The hyper?ne sublevel correlation spectra reveal that the Al and B nuclei are in the coordination sphere of Nd3+ ions for aluminoborate glasses; however, only 27Al signals could be observed for aluminosilicate and aluminogallate glasses. Owing to the increased number of AlO4-BO3 connections and 11B nuclei around the Nd3+ ions, B has a signi?cant e?ect on the luminescence properties of the Nd3+ ions. The increase in GaO4 or SiO4 does not change the three dimensional-tetrahedral network, and the coordination environment of Nd3+ ions varies slightly. Thus, the e?ect of Ga2O3 and SiO2 on the luminescence properties of the Nd3+ ions is not as great as that of B2O3.
关键词： Glass structure,Local environments of rare-earth ions,EPR,Luminescence properties,NMR
更新于2025-09-10 09:29:36
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UV-Vis spectroscopy
摘要： UV-Vis reflectance spectroscopy has been widely used as a non-invasive method for the study of cultural heritage materials for several decades. In particular, FORS, introduced in the 1980s, allows to acquire hundreds of reflectance spectra in situ in a short time, contributing to the identification of artist’s materials. More recently, microspectrofluorimetry has also been proposed as a powerful non-invasive method for the identification of dyes and lake pigments that provides high sensitivity and selectivity. In this chapter, the concepts behind these spectroscopic methodologies will be discussed, as well as the instrumentation and measurement modes used. Case studies related with different cultural heritage materials (paintings and manuscripts, textiles, carpets and tapestries, glass, metals, and minerals), which show the usefulness of UV-Vis reflectance spectroscopy and microspectrofluorimetry applied to the study of artworks, will also be presented.
关键词： glass,reflectance,microspectrofluorimetry,textiles,FORS,carpets and tapestries,paintings and manuscripts,minerals,non-invasive,metals,UV-Vis spectroscopy
更新于2025-09-10 09:29:36
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Crystallization kinetics and the dielectric properties of SrO-BaO-Nb2O5-B2O3 glass-ceramics
摘要： Glass-ceramics materials of SrO-BaO-Nb2O5-B2O3 system have been prepared by conventional melt-casting followed by controlled crystallization. The crystallization kinetics, phase evolution, microstructure, breakdown strength and dielectric properties have been explored by differential scanning calorimetry (DSC), X-ray diffractometer (XRD), scanning electron microscope (SEM), and multifunction LCR meter. The results reveal that crystallization mechanism of this glass is believed to be three-dimensional interfacial growth. It was observed that predominant crystalline phase is Ba0.39Sr0.61Nb2O6 in these glass-ceramics crystallized at 750 °C, and the grain size increases with increase in crystallization time. The uniform microstructure can be seen clearly in glass-ceramics crystallized at 750 °C for 3 h, and the obtained glass-ceramics was found to possess optimal properties. Moreover, glass-ceramic with a dielectric constant of 58, the dielectric loss of 0.007 and breakdown strength of 1010 kV/cm could be achieved. In addition, energy storage density of glass-ceramics reached a maximal value of 2.62 J/cm3. To our knowledge, studies on SrO-BaO-Nb2O5-B2O3 glass-ceramics without SiO2 as a glass network former are few, and the melting temperature of the B2O3-based glass is lower than that of SiO2-based glass, which is conducive to the purpose of energy saving. These findings indicate that this glass may be a candidate for high energy-storage capacitors.
关键词： Energy storage density,Glass-ceramics,Crystallization,Dielectric properties
更新于2025-09-10 09:29:36
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Yb3+/Tb3+/Ho3+: phosphate nanophase embedded glass ceramics: enhanced upconversion emission and temperature sensing behavior
摘要： Yb3+/Tb3+/Ho3+ tri-doped transparent phosphate glass–ceramics (GCs) were successfully synthetized by a conventional melt-quenching technique with subsequent glass crystallization. The formation of phosphate nanocrystals (NCs) with leucite structure was confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected-area electron diffraction (SAED). The variation of the decay curves confirms the accumulation of active centers into the NCs lattice. Hence, the UC emission intensity of Yb3+/Tb3+/Ho3+ doped GC610 sample is greatly enhanced relative to that in precursor glass (PG). And the UC energy transfers processes were systematically analysis. The result shows that the energy transfer of Ho3+→Tb3+ exists while Yb3+ as a sensitizer ion. Furthermore, the temperature-dependent UC luminescence and temperature sensing behaviors of the prepared materials based on the thermally coupled levels of Tb3+: 5D4 and Ho3+: 5F5 in the temperature range of 298–648 K were systematically investigated, to explore its possible application as optical thermometric medium, by utilizing the fluorescence intensity ratio (FIR) technique. The relative sensitivity (Sr) of 7.5 × 10?3 K?1 and absolute sensitivity (Sa) of 22 × 10?3 K?1 are achieved in the Yb3+/Tb3+/Ho3+ tri-doped GC. This GC materials is a very promising candidate for optical temperature sensors.
关键词： Yb3+/Tb3+/Ho3+ tri-doped,phosphate glass–ceramics,upconversion emission,temperature sensing,optical thermometry
更新于2025-09-10 09:29:36