Precursor Glass Research Articles

Preparation and improved luminescent properties of Tb3+/Yb3+ co-doped Na2O–CaO–SiO2–Al2O3–ZnO–CaF2 transparent glass-ceramics

Transparent glass-ceramics containing CaF2 single-phase or CaF2/Ca5(PO4)3F two-phase were obtained by heat-treating the precursor glass. Compared with the precursor glass, the glass-ceramics containing CaF2 crystal with low phonon energy greatly enhance the emission intensity. Further research was conducted on the influence of various crystallization procedures on the luminescent properties of the glass-ceramic, and the procedure crystallized at 660 °C for 4 h was determined to be the optimal heat treatment. The SEM results indicate that the crystal size of the glass-ceramics is in the nanometer scale, which guarantees the possibility of its optical application. The three-photon absorption process of the Tb3+/Yb3+ co-doped glass-ceramics containing CaF2 single-phase was confirmed based on the up-conversion emission spectra excited at different power of 980 nm laser. The chromaticity coordinates of the Tb3+/Yb3+ co-doped glass-ceramic are located in the green region, indicating its potential applications in green lighting and other optical display devices.

Synthesis and up-conversion luminescence properties of Ho3+-Yb3+ co-doped glass ceramics with perovskite structure

By using melt solidification crystallization method, Ho3+-Yb3+ co-doped transparent glass ceramics (GCs) containing LaTiO3 microcrystal were successfully prepared. The structure of the GCs was characterized by X-ray diffraction (XRD), which proved that LaTiO3 microcrystal was precipitated in the precursor glass (PG). The structures of PG and GCs were studied by infrared spectrum, which showed that a new absorption peak appeared in the GCs, which was attributed to the stretching vibration of the Ti-O bond in the [TiO6] octahedral group, and it further demonstrated the precipitation of the LaTiO3 microcrystal. By studying the up-conversion luminescence (UCL) properties, it is found that there were three emission peaks at 546, 652 and 484 nm, which are attributed to the 5F4/5S2 → 5I8, 5F5 → 5I8 and 5F3 → 5I8 transitions of Ho3+, respectively, and the optimal doping concentrations of Ho3+ and Yb3+ were determined. The chrominance coordinate of Ho3+-Yb3+ co-doped glass ceramic (GC) is situated in the green light area and the color purity is as high as 98.03 %. The researches above show that Ho3+-Yb3+ co-doped GCs with LaTiO3 microcrystal have a wide application prospect in green luminescence.

Glass-ceramics prepared from desulfurized electrolytic manganese residue and the nucleation promotion effect of calcium fluoride in glass phase transition

Electrolytic manganese residue (EMR) is toxic industrial solid waste. Electrolytic manganese enterprises have established a desulfurization and sulfuric acid production process to address its storage risks leaving desulfurized EMR (DEMR). In this study, DEMR was used as a raw material to prepare glass-ceramics. A method of melting and one-stage heat treatment was used to realize controlled crystallization of diopside, with calcium fluoride sludge (FS) as a nucleating agent. The impact of CaF2 on the glass network structure, as well as on the microstructure and performance of the glass-ceramics, are discussed. CaF2 can greatly improve the nucleation ability of glass precursors. When the addition of FS is small, the phase transition of glass is dominated by the diffusion of atoms and growth of diopside, forming dendritic crystals. When introducing more FS, the glass-ceramics form smaller island-shaped crystals due to many nucleation sites. The prepared glass-ceramics show excellent mechanical properties and chemical stability. Its hardness exceeds 6.5 GPa, with bending strength over 110 MPa. The acid resistance of glass-ceramics is higher than 99.5%, and the toxic metals in the raw materials are stable solidified. This study perfects the technology of EMR desulfurization pretreatment, which provides an effective graded recycling approach for EMR.

Realizing Superior Luminescence in Oxyfluoride Glass‐Ceramics by Enhancing Nano‐Micro Phase Separation

AbstractIn this work, a novel series of oxyfluoride glasses‐ceramics (GCs) is developed by enhancing the phase separation through the substitution of LaF3 for La2O3. The thus‐derived GCs exhibit a remarkable 2700‐fold increase in up‐conversion (UC) luminescence of Er3+ ions compared to the precursor glass. From the 19F Nuclear Magnetic Resonance analysis, this enhancement is attributed to the structural disorder‐to‐order transition in the fluoride‐rich phase. Upon isothermal heat treatment, the translucent GCs transform into transparent ones, making UC luminescence even stronger. The enhanced UC luminescence leads to strong temperature‐sensing ability of the studied glasses. The nano‐micro phase separation is clarified by atomistic simulations and scanning electron microscopy. This study implies that phase separation engineering is a powerful way to achieve superior photonic performances.

Antifouling performance of TiO2-based SiO2–Na2O–K2O glass-ceramic coatings in marine environments

Biofouling refers to the accumulation of organisms on artificial surfaces. This phenomenon poses significant challenges in industrial processes, including reduced energy efficiency and increased fuel consumption. Antifouling coating systems are designed to prevent biofouling on artificial surfaces. Currently, there is a growing focus on developing eco-friendly solutions to mitigate the environmental impact of these antifouling coatings. In this study, the antifouling (AF) performance of a TiO2-based borosilicate glass-ceramic coating (Ti-GCC) system was evaluated in terms of barnacle settlement on the coating surface. To create anatase crystals in a coating, a special precursor glass (Ti-PG) formulation, Na2O–K2O–TiO2–B2O3–Al2O3–SiO2–P2O5–F, with <10 % of Na2O and 20 % TiO2 along with other components was used. The Ti-PG was characterised through X-ray fluorescence (XRF) spectroscopy to determine the chemical composition. The milled Ti-PG with additives was applied on a steel substrate using a spray gun and devitrified at 550 °C and 860 °C for 6 min. The phase determination, surface evaluation, thermal behaviour analysis, and AF evaluation of the Ti-GCC were conducted through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), non-contact optical profilometry (NCOP), and thermogravimetric-differential thermal analysis (TG-DTA). The anatase crystal was determined to exist in the Ti-GCC structure. Although the AF evaluation results revealed that the Ti-GCC system had barnacle settlement (73.9 barnacles/cm2), the surface could be easily cleaned. Additionally, the EDS results confirmed that no biofilm was formed on the Ti-GCC's surface. The roughness of the surface before the AF evaluation and after the cleaning procedure was measured using NCOP, and the difference in surface roughness was examined. The small difference in the roughness of the surfaces suggested that the Ti-GCC system exhibited resistance to microbially induced corrosion (MIC). Furthermore, EDS mapping did not provide any evidence of barnacle diffusion into the coated layer. Furthermore, the thickness measurements of the cross-sectional area of the Ti-GCC before and after AF evaluation through SEM proved that coating depletion did not occur.

Crystallization of Na2SrGe6O14:Cr3+,Yb3+ Glass Ceramics Enabling a Watt‐Level Output Power NIR‐I/NIR‐II Lighting Source

AbstractNear‐infrared (NIR) phosphor‐converted light‐emitting diodes (pc‐LEDs) lighting sources are applied in non‐destructive examination and illumination supplements for night monitoring. As a critical component of NIR pc‐LED, NIR phosphors are required to possess a high external quantum efficiency (EQE), super thermal stability, and broadband emission to meet applications. Here, Na2SrGe6O14:Cr3+ (NSGO:Cr) glass ceramics (GC) bulk via highly crystallization from glass precursor is fabricated and demonstrates an ultrabroad emission band centered at 815 nm with a full width at half‐maximum (FWHM) of 214 nm and a high EQE of 49.2%. Moreover, Yb3+ co‐doping significantly enhances Cr3+ → Yb3+ energy transfer (ET) due to the stronger Yb3+: 2F7/2‐2F5/2 absorption. Benefiting from the ET process, the Cr/Yb co‐doped GC exhibits NIR‐I/II emission with improved thermal stability from 30.1% to 65.0%. Furthermore, an encapsulant‐free NIR GC‐converted LED (GCc‐LED) is prepared and exhibits 52.2 mW NIR output power with a high photoelectric conversion efficiency (PCE) of 19.4%. Under a large current of 600 mA, the NIR device exhibits a watt‐level output power of 922.4 mW with a PCE of 9.1%. Compared to conventional NIR powder phosphors, NSGO:Cr/Yb GC with high performance can open up an avenue for the fabrication of high power NIR lighting sources.

A non-rare-earth-doped self-activated blue fluorescent material of transparent glass-ceramics containing single-phase NaY(MoO4)2: The controllable synthesis, crystallization behavior and luminescent properties

The glass with components of 50SiO2-20B2O3-20Na2O-6ZnO-3MoO3-1Y2O3 (mol%) was synthesized by the melt-quenching method, and the corresponding glass-ceramics were obtained after heat treatment. The crystallization behavior of the glass was characterized by the DSC test. By carefully examining the structure and grain size of the NaY(MoO4)2 crystals with scheelite structure using XRD and SEM, it can be confirmed that the crystal size steadily increases after increasing the crystallization temperature or extending the crystallization time, which is in the range of 27–45 nm. The transmittance of glass-ceramics somewhat declines compared to the precursor glass, although it remains high (>80 %). Under the excitation of 365 nm, the glass-ceramic shows a broad emission band, which is related to the charge transfer of Mo6+→O2- in the [MoO4]2- unit. The glass-ceramic is heat-treated at 590 °C for 3 h as the optimal heat treatment schedule, and its CIE chromaticity coordinate is located in the blue-light region, indicating the potential application of the non-rare-earth-doped self-activated light-emitting glass-ceramics containing single-phase NaY(MoO4)2 in the blue light-emitting field.

Broadband near-infrared emission covering S+C+L in Er3+-doped nanocrystal modified PbO-PbF2-Bi2O3-Ga2O3 glasses

This paper reports a broadband near-infrared emission ranging from 1400 to 1660 nm in Er3+-doped nanocrystal-modified PbO-PbF2-Bi2O3-Ga2O3 glasses. After heat treatment, X-ray diffraction measurements were performed and confirmed that PbBiO2F nanocrystals were precipitated in the precursor glasses. As nanocrystals alter the local environment around Er3+ ions, the emission spectrum of the transition 4I13/2→4I15/2 is broadened and enhanced, resulting in a broadband emission and an FWHM wavelength range of 143.4 nm from 1470.1 to 1613.5 nm, which overlaps the S+C+L optical communications windows. In addition, the emission intensity of the 4I11/2→4I13/2 transition is also found to be increased after heat treatment, thus enhancing the λ∼2750 nm emission intensity. Our results indicate that an Er3+-doped nanocrystal-modified PbO-PbF2-Bi2O3-Ga2O3 glass could be a competitive candidate material that can offer improved bandwidths for S+C+L broadband amplifiers used in very high-capacity optical communications systems.

Up-conversion color tunable and red luminescence of Ho3+/Yb3+ co-doped glass ceramics containing NaLaSiO4 crystals

By using the melt-annealing method, silicate precursor glasses were prepared. Optimal heat treatment conditions for glass ceramics at 610 °C for 90 min were established through a series of tests. Glass ceramics containing NaLaSiO4 crystals with β-K2SO4 structure were successfully synthesized after heat treatment. XRD patterns of glass ceramics were successfully fitted using Rietveld refinement, with rare earth ions entering the lattice by replacing sites of La resulting in a reduction in cell volume. A tunable emission from green light to red light was achieved by varying the Yb3+ doping concentration. By varying the concentration of Ho3+, the intensity of the up-conversion emission was significantly increased while maintaining high color purity in red light. The optimal concentration of Ho3+ was 0.4%, when the red light color purity was 98.9%. These results indicate that glass ceramics containing NaLaSiO4 crystals co-doped with Ho3+-Yb3+ could be used for up-conversion color-tunable emission and red luminescence.

Effects of Cr3+ content on the structure and fluorescence properties of SiO2–Na2O–Y2O3–P2O5 glasses and glass-ceramics with Na3YSi2O7 crystal phase

In this work, the Cr2O3-doped SiO2–Na2O–Y2O3–P2O5 precursor glasses were prepared by the melt-quenching method. A two-step heat treatment was used to obtain Cr2O3-doped glass ceramics with oxyapatite-silicate-type Na3YSi2O7 crystal phase. The optimum heat treatment schedule was determined to be heat-treated 660 °C/1 h + 760 °C/20 min by XRD and fluorescence spectra. Compared with precursor glasses, the luminescent properties of the Cr2O3-doped glass-ceramics containing Na3YSi2O7 crystals have been greatly improved. The optimum Cr2O3-doping amount was determined to be 0.4 mol%. Under the excitation of 490 nm, the glass-ceramics have a broad emission peak centered at 980 nm in the near-infrared region, which belongs to the 4T2→4A2 transition of Cr3+ ions. This work shows that the Cr2O3-doped glass-ceramic materials have the potential to be used as near-infrared luminescent materials in the fields of illumination display, bio-fluorescence imaging, solar cells, etc.

Mechanical crystallization induced Sm3+-doped CsPbBr3 quantum dots glass for high-sensitivity temperature sensing

The traditional preparation methods of quantum dots (QDs) for temperature sensing are limited to self-crystallization and secondary heat treatment processes, which requires precise control of the experimental equipment and conditions. In this paper, CsPbBr3 QDs are successfully obtained by friction crystallization in the prepared precursor glass. The results show that when the glass network structure is subjected to continuous mechanical impact, the thermal kinetic energy of the fracture surface increases. Therefore, the combination of relatively loose structure and local thermal energy supply more excellent space for the nucleation and growth of CsPbBr3 QDs. Furthermore, the PL enhancement is confirmed to be occur in Sm3+ ions doped CsPbBr3 QDs, which is due to the increase of density of exciton states near the edge of the band, thus facilitating radiative recombination. Significantly, this material has a favorable performance of temperature sensing and thermal stability, with the maximum relative sensitivity of 3.09 % K−1. This work provides an energy-saving and green way for the preparation of Sm3+ ions doped QDs, and the materials provide potential applications in the field of temperature sensing.

Photocurable 3D-Printed PMBG/TCP Scaffold Coordinated with PTH (1-34) Bidirectionally Regulates Bone Homeostasis to Accelerate Bone Regeneration.

Bone defect repair remains a major clinical challenge that requires the construction of scaffolds that can regulate bone homeostasis. In this study, a photo-cured mesoporous bioactive glass (PMBG) precursor is developed as a tricalcium phosphate (TCP) agglomerant to obtain a double-phase PMBG/TCP scaffold via 3D printing. The scaffold exhibits multi-scale porous structures and large surface areas, making it a suitable carrier for the loading of parathyroid hormone (PTH) (1-34), which is used for the treatment of osteoporosis. In vitro and in vivo results demonstrate that PMBG/TCP scaffolds coordinated with PTH (1-34) can regulate bone homeostasis in a bidirectional manner to facilitate bone formation and inhibit bone resorption. Furthermore, bidirectional regulation of bone homeostasis by PTH (1-34) is achieved by inhibiting fibrogenic activation protein (FAP). Thus, PMBG/TCP scaffolds coordinated with PTH (1-34) are viable materials with considerable potential for application in the field of bone regeneration and provide an excellent solution for the design and development of clinical materials.

Warm to neutral white light emissions from Dy3+–Eu3+ co-doped glass ceramics containing NaBSiO4 crystalline phase for W-LEDs applications

This paper reports on the structural, optical and luminescence studies of Dy3+–Eu3+ co-doped glass ceramics that are obtained via thermal treatment method. The initial confirmation on glass ceramics with the formation of NaBSiO4 crystalline phase was made through XRD study. The FTIR study showed the vibrations of network formers (B2O3, SiO2) and other functional groups. The quantity of non-bridging oxygens (NBOs) are increased in the glass ceramics with increase in annealing temperature. The absorption spectra (UV–visible-NIR) showed the possible transitions of Dy3+ and Eu3+ ions in the glass ceramics. A red-shift in the absorption band-edge and reduction in the optical band gap values were obtained for glass ceramics owing to their heating temperatures. Photoluminescence studies showed the excitations of Dy3+ and Eu3+ ions under 575 nm and 613 nm emission wavelengths. The obtained NaBSiO4 crystalline phase in the glass ceramics has enhanced the luminescence intensity, and lifetimes of Dy3+ and Eu3+ ions compared to unheated precursor glass when excited under 350 nm and 393 nm. Color chromaticity diagram and correlated color temperature (CCT) values showed a shift in the color of light from warm white of precursor glass to neutral white of glass ceramics. The overall results justify the possibility of considering the Dy3+-Eu3+ co-doped glass ceramics as efficient materials for solid-state lighting applications like W-LEDs.

Silicate glass-ceramic fibers with nonlinear optical crystals: Evaluation of propagation loss and comparison to optical materials

Optical glass fibers can propagate light signals, while their control depends on nonlinear optical crystals. In this study, we fabricated nonlinear optical glass-ceramic (GC) fibers in which the polar fresnoite phase was crystallized based on perfect surface crystallization (PSC) in the SrO–TiO2–SiO2 system. GC fibers free from voids were obtained from precursor glass fibers with a diameter of ∼100 μm by controlling PSC. The propagation loss of a GC fiber was evaluated to be ∼0.37 dB/cm, which is comparable to that of the LiNbO3 single-crystal optical waveguide.

A new photoelectric niobate glass ceramic material: Up-conversion optical thermometry and dielectric energy storage

To develop new inorganic multifunctional materials, a series of Yb3+/Er3+ doped precursor glasses (PGs) were fabricated through melt quenching technique, and a novel niobate transparent photoelectric glass ceramic (GC) was gained via controlled crystallization of PG. Compared with PG, the up-conversion (UC) luminescence performance is significantly increased in GC. Utilizing the temperature dependence of the emission intensity of Er3+ ions, the dual-mode optical temperature measurement is realized through fluorescence intensity ratio (FIR) methods. The ultimate absolute sensitivity (Sa-max) and relative sensitivity (Sr-max) based on the thermal/non-thermal coupling energy levels (TCELs/NTCELs) are 0.68 %K−1 and 0.85% K−1, respectively. Moreover, the single-layer capacitor made of GC can release energy density of 0.83 J/cm3 (@600 kV/cm) and power density of 210 MW/cm3. This work indicates that niobate transparent glass ceramics are expected to be applied in the optical thermometry and pulse energy storage field.

Yb3+ NIR emission enhancement in dichroic Cu-containing glass for solar spectral conversion

Ytterbium and copper co-doped phosphate glass containing plasmonic Cu particles showing dichroism was synthesized and the impact on Yb3+ near-infrared (NIR) emission evaluated. While the co-doped precursor glass exhibited ultraviolet to NIR luminescence down-shifting owing to copper(I), the dichroic glass displayed an enhanced NIR emission which is reported herein for the first time. It was found most favorable for Cu+ excitation around 360 nm. Scattering by Cu particles is suggested to produce the emission boost attractive for solar cell applications.

Research on Preparation and Luminescence Properties of Tm3+ -doped Glass Ceramics Containing NaLa(MoO4)2

In the world of light-emitting diodes, Tm3+-doped glass ceramics are a crucial fluorescent material. In this study, melt-crystallization was used to create glass ceramics that were Tm3+-doped and included crystalline NaLa(MoO4)2. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmittance, and photoluminescence spectroscopy were used to examine the structure, morphology, and luminescence characteristics of glass ceramics (PL). According to the findings, keeping the precursor glass at 660 °C for two hours produced microcrystals with an average size of 280 nm. Also covered is how the concentration of Tm2O3 doping affects the luminous characteristics of glass ceramics. The strongest blue light is produced at 454 nm (1D2→3F4) when Tm2O3 concentration is 0.8 mol%. The findings demonstrate that Tm3+-doped glass ceramics containing NaLa(MoO4)2 crystalline phase have promise for use in the area of color displays.

Structure, luminescence and thermal stability of Dy2O3–Eu2O3 co-doped transparent glass-ceramics containing Y2Sn2O7 crystal

A new transparent glass-ceramic containing Y2Sn2O7 crystal was synthesized utilizing the melt crystallization method. By using XRD, SEM, and DSC curves to identify the phase structure of the samples and observe their microscopic morphology, the optimal heat treatment conditions for the samples were determined to be 710 °C/2 h. Using the fluorescence probe characteristics of Eu3+, the different microstructures of precursor glasses and glass-ceramics were explored. The emission spectra of Dy2O3–Eu2O3 co-doped glass-ceramic samples showed three distinct emission peaks at 482 nm (Dy3+: 4F9/2 → 6H15/2), 575 nm (Dy3+: 4F9/2 → 6H13/2) and 614 nm (Eu3+: 5D0→7F2), while the emission spectra demonstrated the existence of energy transfer of Dy3+→Eu3+. Warm white light with low color temperature may be obtained by Dy2O3–Eu2O3 co-doped glass-ceramic samples, depending on the chromaticity coordinates and color temperature. The emission spectra of 0.4%Dy2O3-0.7%Eu2O3 co-doped glass-ceramic samples in the temperature range of 298 K–473 K show that at 423 K, the emission intensity at 482 nm, 575 nm, and 614 nm can still reach 71.5%, 78.8%, and 80.0% of the room temperature. We calculated the activation energy as 0.293 eV, and the color shift at 423 K was 7.3 × 10−3. The findings demonstrate the exceptional thermal stability of transparent glass-ceramics containing Y2Sn2O7 crystal and their prospective use in the manufacture of W-LEDs.

Luminescence, optical and temperature sensitive characteristics of Tm3+ /Yb3+ doped fluoride phosphosilicate glass ceramics

Yb3+/Tm3+ doped fluoride phosphosilicate glass ceramics with Sr6Ca4(PO4)6F2 nanocrystals were prepared by the controlled crystallization method. The research results of up-conversion (UC) spectra showed that the optimal dopant concentration of Yb3+ and Tm3+ was 3.0 and 0.1 mol%, respectively. In the visible range, the transmissivity of the precursor glass (PG) was close to 90%, while that of glass ceramics was approximately 82%. And the luminescence intensity of glass ceramics was stronger than that of PG. The Rietveld XRD refinement results confirmed that Yb3+ and Tm3+ ions partially entered the Sr6Ca4(PO4)6F2 crystal to form the solid solution. The highest relative sensitivity (Sr-max) of glass ceramics based on thermally coupled energy levels (TCELs) was 2.77% K-1 (@298 K). In view of non-TCELs, the highest absolute sensitivity (Sa-max) of glass ceramics was 12.21% K-1 (@698 K). These findings demonstrate that the as-prepared glass ceramic can be expected to be suitable for optical temperature sensing applications.

Sintering YAG:Ce phosphor ceramic layers onto glass substrates by CO2 laser for WLED applications

Cerium-doped yttrium aluminum garnet (YAG:Ce) phosphor layers were sintered onto glass using CO2 laser. The layer adhesion was found to depend on the spin coating thickness. The x-ray diffraction indicated the formation of YAG phase, with minor impurities of Y2SiO5 and Y4Al2O9. When the coating thickness was 65 μm, the laser beam reacted thoroughly with glass and YAG precursors, and a liquid phase was formed, producing a thin amorphous layer (∼5 μm) on the surface grooves. However, when the thickness was increased to 170 μm, the laser beam could not penetrate to react entirely with YAG precursors, resulting in more raw residues and poor adhesion. The sintered YAG:Ce phosphor layers on glass were characterized via photoluminescence, presenting yellow emission with a thermal quench to 75% at 125 °C, which is comparable to that of the solid-state reacted YAG:Ce ceramics.