Inorganic Glasses Research Articles

Multifunctional optical materials based on transparent inorganic glasses embedded with PbS QDs

Quantum dot (QD)-embedded glass, which is a high-performance multifunctional optical material, has the combined advantages of excellent optical properties of QDs and easy processing of glass. In this study, an inorganic PbS QD embedded multicomponent glass, which produces variable emission at different ultraviolet (UV) excitation wavelengths, is synthesized. The samples are fabricated via a facile melt-quenching method and their structural, optical, photoluminescent, and morphological properties are discussed. The QD glass exhibits broad-band UV excitation in the range of 250–400 nm, and the full width at half maximum of the emission peaks of the QD glasses reaches 177.8 and 158.5 nm at room temperature under an excitation of 365 and 310 nm, respectively. Notably, white light emission with a high color rendering index is obtained under UV excitation at 350 and 365 nm by doping blue light emitting rare earth (RE) Tm3+ ions into the system. The doped samples exhibit excellent color stability and their CIE coordinates shift along the Planck blackbody locus with increasing temperature. Further, based on the differences in the luminescence mechanisms of the PbS QDs and Tm3+ ions, the application potential of the RE-doped PbS QD-embedded glasses in optical thermometry is discussed. The results demonstrate the application potential of these optically multifunctional inorganic QD glasses in the fields of optical conversion, anti-counterfeiting, white light illumination, and non-contact optical temperature measurement.

A Melt‐Quenched Luminescent Glass of an Organic–Inorganic Manganese Halide as a Large‐Area Scintillator for Radiation Detection

AbstractGlass is a group of materials with appealing qualities, including simplicity in fabrication, durability, and high transparency, and they play a crucial role in the optics field. In this paper, a new organic–inorganic metal halide luminescent glass exhibiting >78 % transmittance at 506–800 nm range together with a high photoluminescence quantum yield (PLQY) of 28.5 % is reported through a low‐temperature melt‐quenching approach of pre‐synthesized (HTPP)2MnBr4 (HTPP=hexyltriphenylphosphonium) single crystal. Temperature‐dependent X‐ray diffraction, polarizing microscopy, and molecular dynamics simulations were combined to investigate the glass‐crystal interconversion process, revealing the disordered nature of the glassy state. Benefiting from the transparent nature, (HTPP)2MnBr4 glass yields an outstanding spatial resolution of 10 lp mm−1 for X‐ray imaging. The superb optical properties and facility of large‐scale fabrication distinguish the organic–inorganic metal halide glass as a highly promising class of materials for optical devices.

Properties, Macro- and Microstructure of a Layered Structural Element Based on Inorganic Glass and a Steel — Glass-and-Metal Composite Rod

Properties, Macro- and Microstructure of a Layered Structural Element Based on Inorganic Glass and a Steel — Glass-and-Metal Composite Rod

Metal-organic framework glass composites.

The melting phenomenon in metal-organic frameworks (MOFs) has been recognised as one of the fourth generation MOF paradigm behaviours. Molten MOFs have high processibility for producing mechanically robust glassy MOF macrostructures, and they also offer highly tunable interfacial characteristics when combined with other types of functional materials, such as crystalline MOFs, inorganic glass and metal halide perovskites. As a result, MOF glass composites have emerged as a family of functional materials with dynamic properties and hierarchical structural control. These nanocomposites allow for sophisticated materials science studies as well as the fabrication of next-generation separation, catalysis, optical, and biomedical devices. Here, we review the approaches for designing, fabricating, and characterising MOF glass composites. We determine the key application opportunities enabled by these composites and explore the remaining hurdles, such as improving thermal and chemical compatibility, regulating interfacial properties, and scalability.

Research progress on surface modifications for phosphors used in light-emitting diodes (LEDs).

Stable and efficient phosphors are highly important for light-emitting diodes (LEDs) with respect to their application in solid-state lighting, instead of conventional lamps for general lighting. However, some problems, like low stability, low photoluminescence (PL) efficiency, and serious thermal degradation, are commonly encountered in phosphors, limiting their applications in LEDs. Surface modifications for some phosphors commonly used in LED lighting, including fluoride, sulphide, silicate, oxide, nitride, and oxynitride phosphors, are presented in this review. By forming a protective surface layer, the stabilities against moisture and high temperature of fluoride- and sulphide-based phosphors were strengthened; by coating inorganic and organic materials around the particle surface, the PL efficiencies of silicate- and oxide-based phosphors were improved; by passivation treatment upon the phosphor surface, the thermal degradation of nitride- and oxynitride-based phosphors was reduced. Various technologies for surface modification are described in detail; moreover, the mechanisms of stability strengthening, PL efficiency improvement, and thermal degradation reduction are explained. In addition, embedding of phosphors in inorganic glass matrix, especially for quantum dots, is also introduced as an effective method to improve phosphor stability for LED applications. Finally, future developments of surface modification of phosphors are proposed.

Optical properties of AIE organic chromophores embedded erbium-doped glass composites fabricated by spark plasma sintering

Encapsulation strategies can isolate the organic chromophores and prevent chemical or photochemical degradation. Inorganic transparent glass matrix has excellent utility as encapsulation matrices. Although the sol-gel method can make this encapsulation, the unclear sol-gel synthetic mechanism limits the synthesis of multi-component glass whose properties can be modified. A novel technique to encapsulate organic chromophores within multi-component glasses is required. In this letter, an organic chromophore was successfully encapsulated within a multi-component glass matrix by spark plasma sintering (SPS). The glass composite has great chemical and photochemical stability. Besides, a non-radiative energy transfer process between rare earth ions and organic chromophores was observed in the glass composites. These results indicate that the glass composite has great potential for optical application, and SPS can be a novel technique for encapsulating organic chromophores.

Opportunities and challenges in CsPbX3@Glasses@Film with High Quality for LCD by Process Optimization towards commercialization

Although backlight display screens based on CdSe quantum dots (QDs) have basically solved the remaining problem of small display gamut, its high preparation cost limits its commercial development. In contrast, perovskite nanocrystals (NCs) with narrow band emission, simple preparation and low cost have made leaps and bounds in next-generation backlit displays luminescent material. However, the instabilities are the main issues to solve before we can apply these materials in modern displays. Researchers have precipitated perovskite NCs in inorganic glass substrates and compounded them with PDMS films for backlighting, but the important factors for commercialization have been ignored: Long-term stability under strong blue light irradiation and preparation cost. In this work, a unique melt-water quenching method combined with composition control was applied to prepare a series of glass powder. The optimal photoluminescence (PL) emission and color coordinates in the color coordinates of glasses powder were elaborately regulated by heat treatment temperature control and the introduction of rare earth Tb. Moreover, the passivation of the glass powder surface through special water treatment greatly improves its stability under long time blue light exposure. After irradiation under 20000 cd/m2 blue light (460 nm) for 500 h, the PL intensity retention rate reaches 85% of commercial CdSe film. The red and green-emitting NCs glasses powder with high photoluminescence quantum yield (PLQY) and stability were combined with PET, PS and PDMS to form a composite film, afterwards, combined with Liquid crystal display (LCD)module shows a fuller color image. Finally, after comparison, PS film was demonstrated to be the most suitable choice for commercialization backlighting.

Facile and cost-effective technique to control europium oxidation states in glassy fluorophosphate matrices with tunable photoluminescence

Inorganic fluorophosphate glasses doped with Eu^{2+}/Eu^{3+} are potential candidates for phosphors for commercial white LEDs. This report presents a fast, inexpensive and effective method of controlling the relative concentrations of Eu^{2+}/Eu^{3+} photoluminescent centers in these glasses. The technique consists of a fast quenching of the melt of initial reagents under appropriate conditions. Eu^{2+}/Eu^{3+} ratio was controlled by carrying out the melting under a reducing atmosphere at a temperature between 1000 and 1200 ^circC for periods of 5 to 15 minutes. The reducing atmosphere was provided by a ’double crucible’ technique and did not require special gas lines during the synthesis. The samples were studied by several complementary experimental methods (X-ray diffractometry—XRD, X-ray photoelectron spectroscopy—XPS, photoluminescence—PL—and photoluminescence excitation—PLE—spectroscopies as well as optical transmission spectroscopy). It was shown that the syntheses resulted in amorphous materials with different relative Eu^{2+}/Eu^{3+} concentration ratios, strongly dependent on the preparation conditions: the temperature and the time of melting in a reducing atmosphere. Moreover, changes in these ratios strongly affected the materials’ PL and PLE spectra. Demonstration of reproducible smooth transition from amaranth to blue luminescence color, with white in between, was the most spectacular result of this work.

Novel ultra-wideband fluorescence material: Defect state control based on nickel-doped semiconductor QDs embedded in inorganic glasses

In recent years, the development of an environmentally friendly quantum dots (QDs) embedded luminous solid by a simple method has attracted considerable attention. In this study, semiconductor ZnS QDs were successfully prepared in an inorganic matrix of amorphous glass, which yielded beneficial broad-band emission in the long-wavelength region of the visible range. The strong red emission belonged to the defect state energy level of the ZnS QDs, which could be enhanced by incorporation of nickel ions into the fixed matrix to regulate the defects state. The novel material had a small self-absorption, wide excitation and emission ranges, and thus potential applications in light-conversion devices, luminescent solar concentrators, and solar cell cover glasses.

Understanding the compositional control on electrical, mechanical, optical, and physical properties of inorganic glasses with interpretable machine learning

Despite the use of inorganic glasses for more than 4500 years, the composition–property relationships in these materials remain poorly understood. Here, exploiting largescale experimental data and machine learning, we develop composition–property models for twenty five properties, which are interpreted using game-theoretic concepts. Specifically, we use a dataset consisting of ∼275,000 glass compositions comprising of 221 different components and 25 properties. This is by far the largest model developed in the literature. The analysis reveals that the glass components, such as network formers, modifiers, and intermediates, play distinct roles in governing the optical, physical, electrical, and mechanical properties of glasses. Interestingly, these components exhibit interdependence, the magnitude of which is different for different properties. While the physical origins of some of these interdependencies could be explained using known phenomena, the majority of the remaining ones remain to be explored. Thus, our work paves the way for decoding the “glass genome”, which can provide the recipe for discovering novel glasses while also shedding light on the fundamental factors governing the composition–structure–property relationships.

Novel PBAT‐Based Biocomposites Reinforced with Bioresorbable Phosphate Glass Microparticles

AbstractBiocomposites based on poly(butylene adipate terephthalate) (PBAT) and reinforced with micro‐particles of inorganic biodegradable phosphate glass (PG) at 2, 10, and 40 wt% are prepared and characterized from a mechanical and morphological point of view. Scanning electron microscope (SEM) images show a good dispersion of the PG micro‐grains, even at high concentrations, in the PBAT matrix, resulting in homogeneous composites. Tensile and dynamic‐mechanical tests, respectively, indicate that Young's and storage moduli increase with PG concentration. The reinforcement of PBAT aims at modifying and tailoring the mechanical and viscoelastic properties of the material to expand its application field especially in the food and agricultural packaging sector, thanks to the similarity of PBAT performance with polyethylene.

Photophysical properties of methylene blue in aqueous solution sprayed onto biological surfaces

The paper presents a set of experiments revealing photophysical processes associated with methylene blue assisted photodynamic inactivation of pathogens on different surfaces, both inorganic (glass) and organic (superficial fascial flaps of chicken and fish and mushroom cap peel). The experiments were performed in normoxic and hyperoxic conditions. The characteristic times of singlet oxygen generation and degradation on the surfaces were evaluated from the analysis of time-resolved signals of singlet oxygen phosphorescence. The photobleaching kinetics of methylene blue on the surfaces were found to be significantly different and dependant on solution oxygenation. The characteristic decay times varied from dozens of seconds for glass to dozens of minutes for fascial flaps and mushroom peel. The interpretation of the experimental results obtained was done on the basis of a set of master equations describing photosensitizer-assisted singlet oxygen generation and photosensitizer photobleaching. The results obtained on methylene blue photodynamics and conclusions made were compared with results of similar experiments performed earlier with Radachlorin photosensitizer.

Interfacial mechanical properties of tetrahydrofuran hydrate-solid surfaces: Implications for hydrate management

Understanding the interfacial mechanical properties between hydrate and solids is vital to designing and fabricating surfaces for hydrate management. Herein, the role of the surface wettability, the type of solid substrate and temperature on the interfacial adhesion properties of tetrahydrofuran (THF) hydrate and ice were examined by force analysis based shearing measurements and molecular dynamics (MD) simulations. The results showed that the adhesion strength of THF hydrate and ice on silica varies with the compositions of coating, and the adhesion strength of ice is larger than that of THF hydrate for all investigated solid substrates. Particularly, in contrast to a linear relationship between 1 + cosθr and hydrate adhesion on organic silanes/thiols/polymer surfaces, the hydrate adhesion on the coated inorganic glass surfaces is enhanced as a function of 1 + cosθr, in which θr is the receding contact angle. MD simulations uncovered that the adhesion strength of ice on solid substrates is dominated by the quasi-liquid water layer, however, that of hydrate is governed not only by the quasi-liquid layer but also newly formed unconventional clathrate cages. This study provides new insights and perspectives into the hydrate adhesion on solid surfaces, which is of help to develop hydrate-phobic coatings for advanced hydrate management.

Rapid Assembly of Cellulose Microfibers into Translucent and Flexible Microfluidic Paper-Based Analytical Devices via Wettability Patterning.

Microfluidic paper-based analytical devices (μPADs) are emerging as powerful analytical platforms in clinical diagnostics, food safety, and environmental protection because of their low cost and favorable substrate properties for biosensing. However, the existing top-down fabrication methods of paper-based chips suffer from low resolution (>200 μm). Additionally, papers have limitations in their physical properties (e.g., thickness, transmittance, and mechanical flexibility). Here, we demonstrate a bottom-up approach for the rapid fabrication of heterogeneously controlled paper-based chip arrays. We simply print a wax-patterned microchip with wettability contrasts, enabling automatic and selective assembly of cellulose microfibers to construct predefined paper-based microchip arrays with controllable thickness. This paper-based microchip printing technology is feasible for various substrate materials ranging from inorganic glass to organic polymers, providing a versatile platform for the full range of applications including transparent devices and flexible health monitoring. Our bottom-up printing technology using cellulose microfibers as the starting material provides a lateral resolution down to 42 ± 3 μm and achieves the narrowest channel barrier down to 33 ± 2 μm. As a proof-of-concept demonstration, a flexible paper-based glucose monitor is built for human health care, requiring only 0.3 μL of sample for testing.

Design of a Novel La3Si6N11:Ce3+ Phosphor-in-Glass Film for High Power Laser Lighting: Luminous Efficiency toward 200 lmW–1

Inorganic fluorescent glass films have been widely considered in the field of high power laser lighting because of their excellent comprehensive properties as fluorescent conversion materials. Herein, we adjust the optimum sintering temperature to prepare a series of La3Si6N11:Ce3+ phosphor-in-glass films (LSN PiFs) with excellent optical properties on a single sapphire structure. The prepared LSN PiF has ultrahigh internal quantum efficiency (IQE) (98%) and excellent thermal stability. The thermal conductivity at room temperature can reach 9.8 Wm–1 K–1. When the temperature is 100 °C, the fluorescence intensity can still be maintained. The LSN:Ce phosphor particles did not react with the glass matrix and retained the original luminescence properties. Moreover, by further adjusting the concentration and thickness of LSN PiF, the luminous flux and luminous efficiency of LSN PiF under optimal conditions can reach 1071.73 and 207.58 lmW–1 under the excitation of 460 nm, which is the optimal result reported so far. In addition, the color rendering index (CRI) and low color temperature (CCT) are 64.05 and 5612.6 K, respectively, and the color coordinates are all close to the white light region. All the results show that LSN PiF has great application prospects in the high quality and high brightness laser lighting field.

Emerging techniques for customized fabrication of glass

Inorganic glasses have been the one of the most important families of inorganic materials used by human society. The ability to fabricate glasses with customized shapes is of high significance for a diverse range of applications. We review the recent advances in the development of techniques for fabricating glass items with pre-designed geometries. Most of these methods are based on the high-temperature densification of the green parts, which are formed by the preshaping of the composites containing inorganic feedstock (e.g., SiO 2 ) by molding, nanoimprinting and 3D printing, with resolutions down to the sub-micron level. These methods have also enabled the fabrication of multicomponent glass systems and the incorporation of traces of metal ions or nanoparticles as dopants with optical functionalities. In this review, these low-temperature routes are compared with the direct 3D printing route for the fabrication of glass by selective laser melting and fused deposition molding, which rely on high-temperature melting/sintering of glass powers or filaments. Finally, the benefits of different methods for fabricating glass in a customizable manner are discussed and potential future directions are highlighted. • Customized fabrication methods for glasses are reviewed. • Pre-shaping of green parts by using the nanocomposites routes are reviewed. • Different 3D printing methods for glasses are discussed. • Potential future directions in glass fabrication are envisaged.

Next-gen approach to the combined micro/macro-scopic measurements of crystal growth in chalcogenide thin films: The case of Se90Te10

Crystal growth in 1 µm Se90Te10 thin films deposited on a variety of substrates was studied by means of a novel combination of direct microscopic and calorimetric measurements. Differential scanning calorimetry (DSC) was used to explore the macroscopic manifestation of the crystal growth in as-deposited Se90Te10 thin films, revealing the native-like crystal growth behavior (very close to that of the bulk glass) in the films deposited on the polymeric foil. The optical microscopy determined the following sequence for the crystal growth rates ur in the thin films deposited on different substrates: urwhite glass> urSiO2 glass> >urKapton. This finding is perfectly consistent with the calorimetric data, and can be explained by the combined influences of the Na+ ions migrating from the white glass substrate to the thin film/substrate interface, and by the compressive stresses arising from the large difference between the thermal expansion coefficients of Se90Te10 and the inorganic glasses. Conformation of the calorimetric and microscopic data was validated by the description of both datasets in terms of a single set of parametrized equations based on the combination of the temperature-resolved screw-dislocation growth model and the macroscopic nucleation-growth model. The novel approach to the crystal growth research in chalcogenide thin films was introduced, demonstrating its unprecedented accuracy, robustness and overall comprehension. All major aspects of this novel approach were discussed in detail, including the necessity to consider not only the substrate properties but also the associated process of structural relaxation that may significantly alter the crystal growth near glass transition.

Frontispiece: Materials Formed by Combining Inorganic Glasses and Metal‐Organic Frameworks

The formation of hybrid materials through the combination of the chemically versatile, functional metal-organic framework (MOF) family is proposed, with ubiquitous, low cost and durable inorganic glasses. The blends and composites hence created may serve to minimise, and eventually solve cost, durability and processability issues of MOFs, whilst retaining their valuable properties.

Single-Parameter Aging in the Weakly Nonlinear Limit

Physical aging deals with slow property changes over time caused by molecular rearrangements. This is relevant for non-crystalline materials such as polymers and inorganic glasses, both in production and during subsequent use. The Narayanaswamy theory from 1971 describes physical aging—an inherently nonlinear phenomenon—in terms of a linear convolution integral over the so-called material time ξ. The resulting “Tool–Narayanaswamy (TN) formalism” is generally recognized to provide an excellent description of physical aging for small, but still highly nonlinear, temperature variations. The simplest version of the TN formalism is single-parameter aging according to which the clock rate dξ/dt is an exponential function of the property monitored. For temperature jumps starting from thermal equilibrium, this leads to a first-order differential equation for property monitored, involving a system-specific function. The present paper shows analytically that the solution to this equation to first order in the temperature variation has a universal expression in terms of the zeroth-order solution, R0(t). Numerical data for a binary Lennard–Jones glass former probing the potential energy confirm that, in the weakly nonlinear limit, the theory predicts aging correctly from R0(t) (which by the fluctuation–dissipation theorem is the normalized equilibrium potential-energy time-autocorrelation function).

Fabrication of Biologically Inspired Electrospun Collagen/Silk fibroin/bioactive glass composited nanofibrous scaffold to accelerate the treatment efficiency of bone repair.

Bone disease and disorder treatment might be difficult because of its complicated nature. Millions of patients each year need bone substitutes that may help them recover quickly from a variety of illnesses. Synthetic bone replacements that mirror the structural, chemical, and biological features of bone matrix structure will be very helpful and in high demand. In this research, the inorganic bioactive glass nanoparticles matrixed with organic collagen and silk fibroin structure (COL/SF/CaO-SiO2) were used to create multifunctional bone-like fibers in this study, which we describe here. The fiber structure is organized in a layered fashion comparable to the sequence in which apatite and neo tissue are formed. The amino groups in COL and SF combined with CaO-SiO2 to stabilize the resulting composite nanofiber. Morphological and functional studies confirmed that crystalline CaO-SiO2 nanoparticles with average sizes of 20 ± 5 nm are anchored on a 115 ± 10 nm COL/SF nanofiber matrix. X-ray photoelectron spectroscopic (XPS) results confirmed the presence of C, N, O, Ca, and Si in the composite fiber with an atomic percentage of 59.46, 3.30, 20.25, 3.38 and 13.61%. respectively. The biocompatibility examination with osteoblast cells (Saos-2) revealed that the CAL/SF/CaO-SiO2 composite nanofiber had enhanced osteogenic activity. Finally, when the CAL/SF/CaO-SiO2 composite nanofiber scaffolds were used to treat an osteoporotic bone defect in a rat model, the composite nanofiber scaffolds significantly promoted bone regeneration and vascularization. This novel fibrous scaffold class represents a potential breakthrough in the design of advanced materials for complicated bone regeneration.