Hybrid Glasses Research Articles

Looking into the future of hybrid glasses.

Glasses are typically formed by melt-quenching, that is, cooling of a liquid on a timescale fast enough to avoid ordering to a crystalline state, and formerly thought to comprise three categories: inorganic (non-metallic), organic and metallic. Their impact is huge, providing safe containers, allowing comfortable and bright living spaces and even underlying the foundations of modern telecommunication. This impact is tempered by the inability to chemically design glasses with precise, well-defined and tunable structures: the literal quest for order in disorder. However, metal-organic or hybrid glasses are now considered to belong to a fourth category of glass chemistry. They have recently been demonstrated upon melt-quenching of coordination polymer, metal-organic framework and hybrid perovskite framework solids. In this Review, we discuss hybrid glasses through the lens of both crystalline metal-organic framework and glass chemistry, physics and engineering, to provide a vision for the future of this class of materials.

Synthesis of new synthetic hybrid glasses using metallic nano-particles and rare-earth: Effect of plasmonic diluents

Borophosphate-based glass materials have the potential to revolutionize optical technology because of their outstanding optical properties, long-lasting nature, and cost-effectiveness. The present research addresses the intricate functions of rare earth and metallic nanoparticles (NPs) in borophosphate glass, which have significant potential for optical photonic and medical applications by incorporating Dy3+ ions and Cu NPs. We developed novel hybrid glasses through the melt-quenching technique, which includes the creation of functional groups and the establishment of bonds between P2O5 and B2O3, as confirmed by FTIR and Raman spectroscopy. UV–visible absorption spectra were used to identify the presence of Cu⁺ and Cu (Saeed et al., 2021) [2]⁺ ions and Cu nanoparticles, with the absorption peaks indicating their respective states. Furthermore, the underlying mechanisms of energy transfer in a glass matrix that is co-doped with dysprosium ions (Dy3+) have been studied. The experimental findings of this research not only provide valuable information about the physical properties of borophosphate glass but also emphasize the collaborative relationship between the rare-earth ion and copper nano-powders. The Tauc plot analysis demonstrated a correlation between the concentration of Cu and Dy dopants and a decrease in the energy band gap of the glass. This suggests that these dopants influence the electronic structure of the glass. This study opens up possibilities for creating innovative photonic materials with customized optical attributes.

Micro-optical elements from optical-quality ZIF-62 hybrid glasses by hot imprinting

Hybrid glasses derived from meltable metal-organic frameworks (MOFs) promise to combine the intriguing properties of MOFs with the universal processing ability of glasses. However, the shaping of hybrid glasses in their liquid state – in analogy to conventional glass processing – has been elusive thus far. Here, we present optical-quality glasses derived from the zeolitic imidazole framework ZIF-62 in the form of cm-scale objects. These allow for in-depth studies of optical transparency and refraction across the ultraviolet to near-infrared spectral range. Fundamental viscosity data are reported using a ball penetration technique, and subsequently employed to demonstrate the fabrication of micro-optical devices by thermal imprinting. Using 3D-printed fused silica templates, we show that concave as well as convex lens structures can be obtained at high precision by remelting the glass without trading-off on material quality. This enables multifunctional micro-optical devices combining the gas uptake and permeation ability of MOFs with the optical functionality of glass. As an example, we demonstrate the reversible change of optical refraction upon the incorporation of volatile guest molecules.

Organic-Inorganic Hybrid Glasses of Atomically Precise Nanoclusters.

Organic-inorganic atomically precise nanoclusters provide indispensable building blocks for establishing structure-property links in hybrid condensed matter. However, robust glasses of ligand-protected nanocluster solids have yet to be demonstrated. Herein, we show [Cu4I4(PR3)4] cubane nanoclusters coordinated by phosphine ligands (PR3) form robust melt-quenched glasses in air with reversible crystal-liquid-glass transitions. Protective phosphine ligands critically influence the glass formation mechanism, modulating the glasses' physical properties. A hybrid glass utilizing ethyldiphenylphosphine-based nanoclusters, [Cu4I4(PPh2Et)4], exhibits superb optical properties, including >90% transmission in both visible and near-infrared wavelengths, negligible self-absorption, near-unity quantum yield, and high light yield. Experimental and theoretical analyses demonstrate the structural integrity of the [Cu4I4(PPh2Et)4] nanocluster, i.e., iodine-bridged tetranuclear cubane, has been fully preserved in the glass state. The strong internanocluster CH-π interactions found in the [Cu4I4(PPh2Et)4] glass and subsequently reduced structural vibration account for its enhanced luminescence properties. Moreover, this highly transparent glass enables performant X-ray imaging and low-loss waveguiding in fibers drawn above the glass transition. The discovery of "nanocluster glass" opens avenues for unraveling glass formation mechanisms and designing novel luminescent glasses of well-defined building blocks for advanced photonics.

The trade-off anionic modulation in metal-organic glasses showing color-tunable persistent luminescence.

Ultralong room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) materials provide exciting opportunities for the rational design of persistent luminescence owing to their long-lived excitons. However, conventional rare-earth-based all-inorganic emitters involve high cost and harsh synthesis conditions, and purely organic systems may require complicated synthesis routes and tedious purification. Therefore, it is highly desirable to develop a cost-effective and easily manufacturable method for achieving color-tunable RTP-TADF with a long afterglow. Herein, we demonstrate a rational strategy to introduce different anions (Cl-, Br- and OAc- ions) into a Zn-based metal-organic scaffold, which can improve the crystal rigidity and achieve a well-balanced RTP-TADF. Both theoretical and experimental studies have demonstrated that the adjustment of different anions can effectively modulate the spin-orbit coupling (SOC) and the energy gap of singlet-triplet states (ΔEST) and then tailor the afterglow lifetime. Moreover, we prepared dye-doped metal-organic hybrid glasses with remarkable potential for the color-tunable afterglow. Therefore, this work not only provides a new horizon for modulating crystal and glass states with color/lifetime-tunable persistent luminescence, but also contributes to optical information storage and anti-counterfeiting technology.

Interfacial alloying between lead halide perovskite crystals and hybrid glasses

The stellar optoelectronic properties of metal halide perovskites provide enormous promise for next-generation optical devices with excellent conversion efficiencies and lower manufacturing costs. However, there is a long-standing ambiguity as to whether the perovskite surface/interface (e.g. structure, charge transfer or source of off-target recombination) or bulk properties are the more determining factor in device performance. Here we fabricate an array of CsPbI3 crystal and hybrid glass composites by sintering and globally visualise the property-performance landscape. Our findings reveal that the interface is the primary determinant of the crystal phases, optoelectronic quality, and stability of CsPbI3. In particular, the presence of a diffusion “alloying” layer is discovered to be critical for passivating surface traps, and beneficially altering the energy landscape of crystal phases. However, high-temperature sintering results in the promotion of a non-stoichiometric perovskite and excess traps at the interface, despite the short-range structure of halide is retained within the alloying layer. By shedding light on functional hetero-interfaces, our research offers the key factors for engineering high-performance perovskite devices.

Siloxene Nanosheets and Their Hybrid Gel Glasses for Broad-Band Optical Limiting.

With the development of laser technology, the research of novel laser protection materials is of great significance. In this work, dispersible siloxene nanosheets (SiNSs) with a thickness of about 1.5 nm are prepared by the top-down topological reaction method. Based on the Z-scan and optical limiting testing under the visible-near IR ranges nanosecond laser, the broad-band nonlinear optical properties of the SiNSs and their hybrid gel glasses are investigated. The results show that the SiNSs have outstanding nonlinear optical properties. Meanwhile, the SiNSs hybrid gel glasses also exhibit high transmittance and excellent optical limiting capabilities. It demonstrates that SiNSs are promising materials for broad-band nonlinear optical limiting and even have potential applications in optoelectronics.

Nonlinear Optical Glass-Ceramic From a New Polar Phase-Transition Organic-Inorganic Hybrid Crystal.

Melt-quenched glasses of organic-inorganic hybrid crystals, i.e., hybrid glasses, have attracted increasing attention as an emerging class of hybrid materials with beneficial processability and formability in the past years. Herein, we present a new hybrid crystal, (Ph3 PEt)3 [Ni(NCS)5 ] (1, Ph3 PEt+ =ethyl(triphenyl)phosphonium), crystallizing in a polar space group P1 and exhibiting thermal-induced reversible crystal-liquid-glass-crystal transitions with relatively low melting temperature of 132 °C, glass-transition temperature of 40 °C, and recrystallization on-set temperature of 78 °C, respectively. Taking advantage of such mild conditions, we fabricated an unprecedented hybrid glass-ceramic thin film, i.e., a thin glass uniformly embedding inner polar micro-crystals, which exhibits a much enhanced intrinsic second-order nonlinear optical effect, being ca. 25.6 and 3.1 times those of poly-crystalline 1 and KH2 PO4 , respectively, without any poling treatments.

Nonlinear Optical Glass‐Ceramic From a New Polar Phase‐Transition Organic‐Inorganic Hybrid Crystal

AbstractMelt‐quenched glasses of organic–inorganic hybrid crystals, i.e., hybrid glasses, have attracted increasing attention as an emerging class of hybrid materials with beneficial processability and formability in the past years. Herein, we present a new hybrid crystal, (Ph3PEt)3[Ni(NCS)5] (1, Ph3PEt+=ethyl(triphenyl)phosphonium), crystallizing in a polar space groupP1 and exhibiting thermal‐induced reversible crystal‐liquid‐glass‐crystal transitions with relatively low melting temperature of 132 °C, glass‐transition temperature of 40 °C, and recrystallization on‐set temperature of 78 °C, respectively. Taking advantage of such mild conditions, we fabricated an unprecedented hybrid glass‐ceramic thin film, i.e., a thin glass uniformly embedding inner polar micro‐crystals, which exhibits a much enhanced intrinsic second‐order nonlinear optical effect, beingca. 25.6 and 3.1 times those of poly‐crystalline1and KH2PO4, respectively, without any poling treatments.

Reversible structural transformation of supramolecular inorganic–organic hybrid glasses and zeolitic-imidazolate frameworks

Molecular metal inorganic–organic hybrid glasses and fibers have been fabricated, which showed highly polarized light after doping the network with organic dyes.

Synthesis–dependent morphological, structural and photophysical properties of semicrystalline KNbO3:SiO2 hybrid silicates

Polycrystalline ceramics of KNbO3 (KNO) were prepared via sol–gel (by acrylamide polymerization), hydrothermal, and solid–state chemistry reactions. Pure orthorhombic perovskite phases crystallized in the Cm2m (38) space group were attained in all cases. Average crystallite sizes ranging 33–44 ​nm and grain structures varying from 350 to 580 ​nm were obtained depending on the implemented synthetic route. Prepared KNO compounds were embedded in porous a–SiO2 sonogel networks at different dopant rates to conform semicrystalline KNbO3:SiO2 hybrid silicates. Results evidence a clear dependence of the structural and optoelectronic properties of the composite glasses on the employed synthesis methodology. The massive porosity of the sonogel matrix and related defective bonding environment promoted strong intermolecular host–guest interactions influencing the electronic states, structural phase transitions, and Raman and luminescent features of the hybrid glasses via surface–assisted mechanisms and chemical charge–transfers. NLO/SHG activity was observed in all hybrid sonogels (HSG) due to the ferroelectric nature of KNO and the average macroscopic crystallite alignment attained along the polycondensation stage of the solid–solutions; where bulk NLO susceptibilities up to 9.10×10−11 ​esu and molecular hyperpolarizabilities in the 10−23 ​esu range, were estimated. Depending on the synthetic method and hybridized in–gap levels, bandgap energy narrowing was observed for the KNO/HSG systems, showing Eg values ranging 2.45–3.30 eV. A synergistic study comprising morphological, structural, spectroscopic, and quadratic NLO/SHG characterizations was performed to explore these novel composites’ structural and photophysical properties for Pb–free ferroelectric/optoelectronic composite applications.

(Invited) Computational Insights to Dielectric Hybrid Glasses Under Nanoscale Confinement for Next Generation Devices

Low and Ultra-k dielectric organosilicate glasses (OSG) are widely used in device interconnect applications such as shallow trench isolation as insulating units. However, the process of gap filling between conducting units has been challenging. One of the challenges is related to the undesired formation of nanovoids in the low-k dielectric material confined inside the trench geometry. Importantly, the effects of such nanoscale device constraints on the structure and mechanical reliability of low-k dielectric hybrid materials are not very well understood. To close this lack of understanding and guide the related experimental efforts we performed molecular dynamics simulations where we explore the role of the molecular structure and connectivity of different low-k dielectric OSG precursors under nanoscale confinement, and predict the resulting elastic and fracture properties. We demonstrated that hyperconnected OSG precursors with aromatic rings, such as the 1,3,5-benzene molecule, pack more homogenously under confinement leading to smaller nanovoids and better mechanical reliability compared to conventionally bridged OSG precursors, such as the ethylene bridged Et-OCS molecule.

Advancing the Mechanical Performance of Glasses: Perspectives and Challenges.

Glasses are materials that lack a crystalline microstructure and long-range atomic order. Instead, they feature heterogeneity and disorder on superstructural scales, which have profound consequences for their elastic response, material strength, fracture toughness, and the characteristics of dynamic fracture. These structure-property relations present a rich field of study in fundamental glass physics and are also becoming increasingly important in the design of modern materials with improved mechanical performance. A first step in this direction involves glass-like materials that retain optical transparency and the haptics of classical glass products, while overcoming the limitations of brittleness. Among these, novel types of oxide glasses, hybrid glasses, phase-separated glasses, and bioinspired glass-polymer composites hold significant promise. Such materials are designed from the bottom-up, building on structure-property relations, modeling of stresses and strains at relevant length scales, and machine learning predictions. Their fabrication requires a more scientifically driven approach to materials design and processing, building on the physics of structural disorder and its consequences for structural rearrangements, defect initiation, and dynamic fracture in response to mechanical load. In this article, a perspective is provided on this highly interdisciplinary field of research in terms of its most recent challenges and opportunities.

Sharp luminescent violet- and blue-emitting stable (Eu3+ → Eu2+: PPA):SiO2 sonogel hybrid glasses: Synthesis, structural and overall photophysical characterizations

Nanostructured Eu2O3:Polyphenylacetylene (Eu2O3:PPA) complexes prepared at different lanthanide content were synthesized as active ligand–to–metal charge–transfer (LMCT) systems. These phosphors were embedded into mesoporous a–SiO2 sonogel hosting networks at different dopant ratios to obtain luminescent (Eu2O3:PPA):SiO2 monolith glasses. The electroactive sonochemical medium of the colloidal sol–phase activates massive Eu3+→Eu2+ self–reduction processes along the polycondensation reaction of the doped emulsions, giving rise to sharp violet (407 nm) and blue (470 nm) PL–emission bands (FWHM ≤18 nm). The unusual violet–lines arise from the 4f65d1→4f7 transitions of Eu2+ ions to produce intense 6P7/2 → 8S7/2 emissions, while the blue–lines are ascribed to overlapping 5D2→7Fj (j = 0, 1) transitions of remanent Eu3+ ions assisted by LMCT and interionic energy transfers. The CIE coordinates of these composites lay within the light violet/blue region and the bandgap energy was reduced up to 2.16 eV for increasing Eu2O3 concentration. Our experimental approach shows that the Eu3+→Eu2+ process occurs at room temperature material processing, without the use of reducing atmospheres, stimulated UV photoreduction, or post–doping functionalization. Results suggest that guest–host redox interactions and Eu/SiO2 surface–assisted mechanisms are responsible for accomplishing a homogeneous self–reduction and the structuring of steady Eu2+–silicates. Extensive morphological, structural, linear and NLO spectroscopic characterizations, CIE–chromaticity, and energy bandgap evaluations, were performed to explore these novel nanostructured composites' physicochemical and photophysical properties, pointing out potential applications in tunable phosphor devices.

Disorder classification of the vibrational spectra of modern glasses

Using the coherent-potential approximation in heterogeneous-elasticity theory with a log-normal distribution of elastic constants for the description of the Raman spectrum and the temperature dependence of the specific heat, we are able to reconstruct the vibrational density of states and characteristic descriptors of the elastic heterogeneity of a wide range of glassy materials. These descriptors are the nonaffine contribution to the shear modulus, the mean-square fluctuation of the local elasticity, and its correlation length. They enable a physical classification scheme for disorder in modern, industrially relevant glass materials. We apply our procedure to a broad range of real-world glass compositions, including metallic, oxide, chalcogenide, hybrid, and polymer glasses. Universal relationships between the descriptors on the one side, and the height and frequency position of the boson peak, the Poisson ratio and the liquid fragility index on the other side are established.

Ionic liquid facilitated melting of the metal-organic framework ZIF-8

Hybrid glasses from melt-quenched metal-organic frameworks (MOFs) have been emerging as a new class of materials, which combine the functional properties of crystalline MOFs with the processability of glasses. However, only a handful of the crystalline MOFs are meltable. Porosity and metal-linker interaction strength have both been identified as crucial parameters in the trade-off between thermal decomposition of the organic linker and, more desirably, melting. For example, the inability of the prototypical zeolitic imidazolate framework (ZIF) ZIF-8 to melt, is ascribed to the instability of the organic linker upon dissociation from the metal center. Here, we demonstrate that the incorporation of an ionic liquid (IL) into the porous interior of ZIF-8 provides a means to reduce its melting temperature to below its thermal decomposition temperature. Our structural studies show that the prevention of decomposition, and successful melting, is due to the IL interactions stabilizing the rapidly dissociating ZIF-8 linkers upon heating. This understanding may act as a general guide for extending the range of meltable MOF materials and, hence, the chemical and structural variety of MOF-derived glasses.

Melting of hybrid organic-inorganic perovskites.

Several organic-inorganic hybrid materials from the metal-organic framework (MOF) family have been shown to form stable liquids at high temperatures. Quenching then results in the formation of melt-quenched MOF glasses that retain the three-dimensional coordination bonding of the crystalline phase. These hybrid glasses have intriguing properties and could find practical applications, yet the melt-quench phenomenon has so far remained limited to a few MOF structures. Here we turn to hybrid organic-inorganic perovskites-which occupy a prominent position within materials chemistry owing to their functional properties such as ion transport, photoconductivity, ferroelectricity and multiferroicity-and show that a series of dicyanamide-based hybrid organic-inorganic perovskites undergo melting. Our combined experimental-computational approach demonstrates that, on quenching, they form glasses that largely retain their solid-state inorganic-organic connectivity. The resulting materials show very low thermal conductivities (~0.2 W m-1 K-1), moderate electrical conductivities (10-3-10-5 S m-1) and polymer-like thermomechanical properties.

Preparation and Structural Characterization of New Photopolymerizable Transparent Aluminum-Phosphate Hybrid Materials as Resins for 3D Printing

The use of a hybrid sol–gel route to prepare silicate hybrid materials and glasses through stereolithography and other photopolymerizable based additive manufacturing techniques has become a major ...

Embedding CoPt magnetic nanoparticles within a phosphate glass matrix

Glasses are materials with highly flexible compositions and high chemical and physical durability. These characteristics make them suitable materials for hosting nanoparticles for different purposes. Hybrid glasses containing magnetic nanoparticles have been highlighted due to their potential for application as ultra-sensitive magnetic sensors and magnetic devices. In this work, phosphate bulk glasses containing 0.5%, 1.0%, and 2.0% in mass of metallic CoPt alloy nanoparticles were prepared by melt-quenching technique. The CoPt nanoparticles were synthesized by reducing metal precursors in a high temperature organic solvent and, in the second step, they were covered with a silica layer in order to protect the nanoparticles for the subsequent melting. The nanoparticles were treated at different temperatures. Heat treatment at 900 °C showed the highest values of saturation magnetization and coercivity, and for that reason these nanoparticles were chosen for incorporation into glass. In the transmission electron microscopy images of the glass containing 2.0% in mass of nanoparticles, the interplanar distance of 0.21 nm was identified and indexed to the 111 plane of CoPt, confirming that the nanoparticles were successfully embedded into the matrix. The UV–Vis spectra presented Co2+ characteristic bands at 528, 578, and 626 nm, indicating that these ions are tetrahedrally coordinated in the matrix. Themagnetic measurements presented behavior close to ferromagnetic, showing that it is possible to prepare a magnetic glass containing bimetallic nanoparticles.

Gold nanoparticles in melting gels

Melting gels were prepared by the sol–gel process from methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES). Two compositions, 75 mol% MTES-25 mol% DMDES and 65 mol% MTES–35 mol% DMDES, were compared. Citrate-capped gold nanospheres were added to the melting gels during the synthesis process in five concentrations 8, 10, 12, 14, and 18 nM. The doped melting gels were studied both before and after their consolidation into hybrid glasses. Oscillatory rheometry and differential scanning calorimetry were employed to determine glass transition temperatures of the gels. According to oscillatory rheometry performed at constant frequency, the gels initially behave as viscous fluids and this continues as temperature is decreased, while recording the evolution of both storage G’(t,ω0) and loss G” (t,ω0) moduli with temperature. Glass transition temperature was determined as the moduli crossover point. Viscosity was dependent on temperature, but showed little variation with stress. As a general trend, viscosity decreased in the doped gels when compared to the undoped gel. UV–Vis spectra were collected to verify the presence of the gold nanospheres and to monitor their size. For the consolidated samples the position of the plasmon peak reflected the interaction between the gold nanospheres and the hybrid glass matrix.