Search Results (556)

In recent years, sustainable recycling approaches for chicken eggshell waste have increased significantly worldwide due to environmental and circular economy benefits. This work aimed to synthesize and characterize a new calcium aluminate powder using chicken eggshell waste as an alternative source of calcium carbonate through mechanical activation and subsequent calcination. The starting formulation consisting of the eggshell waste (CaCO₃):Al₂O₃ (1:1) ratio was subjected to a high-energy milling process for 0 h, 15 h and 30 h and subsequent calcination at 1200 °C for 4 h. The resulting calcium aluminate powders have been investigated using X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscopy (SEM), and photoluminescence techniques. After calcination, a calcium aluminate-based composite powder with an average crystallite size between 46.45 nm and 52.27 nm and a predominance of the CaAl₂O₄ phase was found. The calcium aluminate powders produced (milled for 15 h and 30 h and calcined at 1200 °C) showed a luminescent behavior, emitting characteristic violet light with a wavelength between 380 and 418 nm. Our findings may provide a novel technical pathway for recycling chicken eggshell waste into calcium aluminate powder with luminescent properties. Full article

In this study, radiation damage in BaFBr and BaF₂ crystals irradiated with 147 MeV ⁸⁴Kr ions up to fluences of (10¹⁰–10¹⁴) ions/cm² was investigated using X-ray excited optical luminescence (XEOL) and pulsed cathodoluminescence (PCL). The effect of oxygen impurities present in the studied crystals was also considered. XEOL spectra revealed bands associated with oxygen impurities occupying halide sites, as well as luminescence bands with maxima at approximately 2.81 eV, 3.7–4 eV, and 2.3 eV. The luminescence at 2.81 eV can be attributed to the recombination of electrons released during X-ray irradiation with holes trapped at specific sites (Type I, PL). The observed highly energetic luminescence is most likely due to perturbed exciton. Such a perturbed exciton can be formed in the configuration F + V_k (${\mathrm{Br}}_2^{-}$) in the presence of the neighboring impurity ion $O^{2-}$. Oxygen impurities play an important role in the formation mechanisms of these centers. High radiation doses lead to crystal degradation. Excitation by a high-power electron pulse induces excitonic luminescence near the oxygen impurity at 4.2 eV. A distinctive feature of the 4.2 eV emission band is its strong intensity at high temperatures. In the decay kinetics of the PCL spectra, a fast component in the nanosecond range dominates, which remains independent of fluence in BaFBr and BaF₂ crystals irradiated with krypton ions. Full article

Zero-dimensional (0D) rare-earth-based metal halides show great potential in photonic and optoelectronic applications owing to their high stability, strong exciton confinement, and tunable energy levels. However, the weak absorption and narrow 4f-4f transitions of rare-earth ions limit their performance. To address this, a series of Sb³⁺-doped Cs₃LnCl₆ (Ln: Yb, La, Eu, Ho, Ce, Er, Tb, Sm, Y) nanocrystals were synthesized via a hot-injection method to study the role of Sb³⁺ doping. Sb³⁺ incorporation induces strong broadband self-trapped exciton (STE) emission from Jahn–Teller-distorted [SbCl₆]³⁻ units and enables efficient energy transfer from STEs to rare-earth ions. As a result, the photoluminescence intensity and spectral tunability are improved, accompanied by bandgap narrowing and enhanced light absorption. Different lanthanide hosts exhibit distinct luminescence behaviors: La-based materials show dominant STE emission, while Tb-, Er-, Yb-, Ho-, and Sm-based systems display STE-mediated energy transfer and enhanced f-f emission. In Eu- and Ce-based hosts, unique mechanisms involving Eu²⁺/Eu³⁺ conversion and Ce³⁺ → STE energy transfer are observed. Moreover, composition-dependent emissions in Sb³⁺-doped Cs₃Tb/EuCl₆ enable a dual-mode color and spectral encoding strategy for optical anti-counterfeiting. This study highlights the versatile role of Sb³⁺ in tuning electronic structures and energy transfer, offering new insights for designing high-performance rare-earth halide materials for advanced optoelectronic applications. Full article

Stimulus-responsive afterglow materials refer to a class of substances whose afterglow characteristics alter under external stimuli, showing considerable potential for advanced applications in anti-counterfeiting, optoelectronic displays, chemical sensing, and bioimaging. Carbon dots (CDs), as an emerging category of afterglow materials, have garnered significant attention due to their stable photophysical and chemical properties, low toxicity, and tunable luminescent energy bands. In recent years, significant progress has been made in the development of stimulus-responsive afterglow CDs, underscoring the need for a systematic summary of this rapidly advancing field. This review summarizes recent advances in CD-based afterglow, encompassing luminescence mechanisms and synthesis strategies. A particular focus is placed on the types of stimulus-responsive afterglow behaviors in CDs, their influence on afterglow performance, and the underlying response mechanisms. The potential applications of these stimulus-responsive afterglow CDs in sensing and information encryption are also discussed in detail. Finally, current challenges and future prospects are outlined, aiming to guide the rational design and development of next-generation stimulus-responsive afterglow CDs. Full article

Long persistent phosphors are widely used in many fields, such as LED, bioimaging, urgent lighting, temperature sensors, etc. Although green and blue long persistent phosphors are well developed, efficient orange-yellow long persistent phosphors are still relatively rare. In this work, a novel orange-yellow long-persistent phosphors Ca₂LuScGa₂Ge₂O₁₂:xPr³⁺ (CLSGGO:xPr³⁺, x = 0.003, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05) are prepared and systematically investigated through its crystal structural information, photoluminescence, and persistent luminescence properties. Under ultraviolet light excitation, these phosphors exhibit orange-yellow emission stemming from the ³P₀ and ¹D₂ multiple electron transitions in the 4f level of Pr³⁺ ion. In addition, the material exhibits bright persistent luminescence. The complex garnet matrix structure of Ca₂LuScGa₂Ge₂O₁₂ provides excellent conditions for the formation of traps. Through the testing of thermoluminescence curve and function fitting, the density and depth of traps are studied; also, the storage and release process of carriers in the material are calculated in detail. A reasonable persistent luminescence mechanism is proposed for CLSGGO:0.01Pr³⁺. This work enriches the research content of photoluminescence and long persistent luminescence of Pr³⁺-doped garnet-based phosphors and paves the way for the future research of long persistent luminescent materials doped with rare earth ions. Full article

Metallogels, three-dimensional supramolecular networks formed through metal–ligand coordination, have emerged as a new generation of adaptive soft materials with promising biomedical potential. By integrating the structural stability and tuneable functionality of metal centres with the dynamic self-assembly of organic gelators, these systems exhibit exceptional mechanical strength, responsiveness, and multifunctionality. Recent studies demonstrate their diverse applications in drug delivery, anticancer therapy, antimicrobial and wound healing treatments, biosensing, bioimaging, and tissue engineering. Interestingly, the coordination of metal ions such as Ru(II), Zn(II), Fe(III), and lanthanides enables the creation of self-healing, thixotropic, and stimuli-responsive gels capable of controlled release and therapeutic action. Moreover, the incorporation of luminescent or redox-active metals adds optical and electronic properties suitable for diagnostic and monitoring purposes. This collection summarizes the most recent advances in the field, highlighting how rational molecular design and coordination chemistry contribute to the development of multifunctional, biocompatible, and responsive metallogels that bridge the gap between materials science and medicine. Full article

The Wushan Loess, situated in the Yangtze Three Gorges region of China, represents the southernmost aeolian loess deposit in China and provides critical insights into Late Pleistocene paleoenvironmental conditions and East Asian monsoon dynamics. Despite its significance, the genesis and provenance of this unique loess deposit remain controversial. This study employs an integrated multi-proxy approach combining detrital zircon U-Pb geochronology, optically stimulated luminescence (OSL) dating, and detailed grain size analysis to systematically investigate the provenance and depositional mechanisms of the Wushan Loess. Three representative loess–paleosol profiles (Gaotang-GT, Badong-BD, and Zigui-ZG) were analyzed, yielding 17 OSL ages, 729 grain size measurements, and approximately 420 analyses per profile were conducted, yielding 1189 valid ages (GT 406, BD 391, ZG 402). OSL chronology constrains the deposition period to 18–103 ka (Marine Isotope Stages 2–5), coinciding with enhanced East Asian winter monsoon activity during the Last Glacial period. Grain size analysis reveals a dominant silt fraction (modal size: 20–25 μm) characteristic of aeolian transport, with coarse silt (20–63 μm) averaging 47.1% and fine silt (<20 μm) averaging 44.2% of the sediments. Detrital zircon U-Pb age spectra exhibit consistent major peaks at 200–220 Ma, 450–500 Ma, 720–780 Ma, and 1800–1850 Ma across all profiles. Kernel Density Estimation (KDE) and Multi-Dimensional Scaling (MDS) analyses indicate a mixed provenance model. Non-negative least squares (NNLS) unmixing confirms this quantitative source apportionment., dominated by proximal contributions from the upper Yangtze River basin (including the Three Gorges area and Sichuan Basin, ~65%–70%), supplemented by distal dust input from the Loess Plateau and northern Chinese deserts (~30%–35%). This study establishes for the first time a proximal-dominated provenance model for the Wushan Loess, providing new evidence for understanding southern Chinese loess formation mechanisms and Late Pleistocene East Asian monsoon evolution. Full article

Flexible upconversion (UC) devices, owing to their unique combination of high–efficiency optical energy conversion and mechanical flexibility, have attracted increasing attention in the fields of optoelectronics, wearable devices, flexible displays, and biomedical applications. However, significant challenges remain in balancing optical performance, mechanical adaptability, long–term stability, and scalable fabrication, which limit their practical deployment. This review systematically introduces five representative upconversion mechanisms—excited–state absorption (ESA), energy transfer upconversion (ETU), energy migration upconversion (EMU), triplet–triplet annihilation upconversion (TTA–UC), and photon avalanche (PA)—highlighting their energy conversion principles, performance characteristics, and applicable scenarios. The article further delves into the flexible transition of upconversion devices, detailing not only the evolution of the luminescent layer from bulk crystals and nanoparticles to polymer composites and hybrid systems, but also the optimization of electrodes from rigid metal films to metal grids, carbon–based materials, and stretchable polymers. These developments significantly enhance the stability and reliability of flexible upconversion devices under bending, stretching, and complex mechanical deformation. Finally, emerging research directions are outlined, including multi–mechanism synergistic design, precise nanostructure engineering, interface optimization, and the construction of high–performance composite systems, emphasizing the broad potential of flexible UC devices in flexible displays, wearable health monitoring, solar energy harvesting, flexible optical communications, and biomedical photonic applications. This work provides critical insights for the design and application of high–performance flexible optoelectronic devices. Full article

Organic–inorganic metal halides (OIMHs) have emerged as highly promising semiconductor materials owing to their outstanding optoelectronic properties. Incorporation of chiral organic molecules into the metal–halide framework enables the construction of chiral OIMHs, which exhibit unique chiroptical phenomena in addition to the intrinsic advantages of perovskite-based semiconductors. This review provides a systematic overview of recent progress in chiral OIMHs, covering synthetic approaches, crystal structures, mechanisms of chirality transfer, circularly polarized luminescence, and circularly polarized light detection. We further highlight the current challenges and outline future research directions, emphasizing the need for strategies that enhance chiroptical responses, stability, and device integration. By bridging fundamental insights with design principles, this work aims to guide the rational development of next-generation chiral functional materials for advanced optoelectronic and spintronic applications. Full article

Chronic alcohol misuse is the leading cause of non-ischemic dilated cardiomyopathy, and the molecular mechanisms underlying the development of alcohol-associated cardiomyopathy (ACM), particularly regarding sex-specific susceptibility and mitochondrial contributions, are not fully known. In this study, we utilized a preclinical model of chronic + binge ethanol consumption to investigate sex differences in disease severity and mitochondrial function. Male and female C57BL/6J mice were fed ethanol or control liquid diets for 30 days, with 2 binge episodes on days 10 and 30. Cardiac morphology was assessed via echocardiography and cardiac function via left ventricular pressure–volume catheterization. Mitochondrial function was evaluated ex vivo using Seahorse XF analysis, ATP luminescence, and AmplexTM Red fluorescence in isolated ventricular mitochondria. Ethanol feeding induced significant cardiac dysfunction and increased transcriptional expression of inflammatory and fibrotic markers in males, while these effects were not seen in females. Despite these sex-specific cardiac effects, mitochondrial respiration, ATP production, collagen protein expression, and oxidative stress were not significantly altered following alcohol exposure in either sex. Further investigation is warranted to assess the potential role of ovarian hormones in this female cardioprotection against chronic + binge ethanol. Full article

One-pot hydrothermal synthesis of boron nitride quantum dots (BNQDs) offers a simple and widely accessible approach to produce nanoparticles with tailored properties for biomedical purposes, including bioimaging and drug delivery. However, growing evidence suggests that most reported BNQD syntheses yield products with insufficient purity and poorly defined structures, limiting their bioapplications where precise composition and controlled synthesis are paramount. In this study, we present a formation mechanism and demonstrate multiple BNQD synthesis pathways that can be precisely controlled by modulating the reaction equilibrium during hydrothermal synthesis under varying experimental conditions. We demonstrate that carbon-related defects shift BNQD photoluminescence (PL) from the UV to the 400–450 nm region, making them suitable for bioimaging, while BO₂⁻ enrichment introduces additional phosphorescence. Furthermore, we show that as-synthesized BNQD suspensions contain significant contamination by non-luminescent ammonium polyborate salts, which is overlooked in prior studies, and disclose the mechanism of their formation as well as effective purification method. Finally, we assess the biocompatibility of purified BNQDs with tuned PL properties and demonstrate their application in bioimaging using Vero cells. The elucidated nanoparticle formation mechanisms, combined with methods for precise control of optical properties, structural defects and sample purity, enable the reproducible production of reliable and effective BNQDs for bioimaging. Full article

Drug-resistant Mycobacterium tuberculosis (Mtb) remains a major global health challenge, prompting the need for new therapeutics targeting essential bacterial proteins. The caseinolytic protein C1 (ClpC1) is a promising drug target, and accurate measurement of its ATPase activity is critical for understanding drug mechanisms. We optimized a sensitive luminescence-based ATPase assay and evaluated ClpC1 constructs with various tag positions and truncations. N-terminal tagging significantly impaired enzymatic activity, whereas C-terminal tagging had no effect; truncated domains showed reduced activity compared to native full-length (FL) ClpC1. Using the native FL-ClpC1, we assessed ecumicin (ECU) and five analogs via ATPase activity and surface plasmon resonance (SPR), using rufomycin (RUF) and cyclomarin A (CYMA) as controls. RUF and CYMA bound tightly (K_D = 0.006–0.023 µM) and inhibited Mtb growth (MIC₉₀ = 0.02–0.094 µM) but modestly stimulated ATPase activity (≤2-fold). In contrast, ECU and its analogs strongly enhanced ATPase activity (4–9-fold) despite slightly weaker binding (K_D = 0.042–0.80 µM) and growth inhibition (MIC₉₀ = 0.19 µM). The partial correlation among AC₅₀, K_D, and MIC values highlights the complementary value of enzymatic, biophysical, and cellular assays. Our assay platform enables mechanistic characterization of ClpC1-targeting compounds and supports rational antitubercular drug development. Full article

Organic–inorganic hybrid metal halides (OIMHs) have attracted widespread attention due to their unique chemical properties, excellent electronic performance, and low-cost fabrication processes. These hybrid materials impose fewer size constraints on the organic components, providing an exciting platform for the molecular-level design of new materials and functionalities. In this review, we discuss the latest progress in OIMHs. Specifically, we summarize recent advances in their structures, synthetic strategies, and luminescence mechanisms, and highlight their applications in light-emitting diodes (LEDs), information encryption and anti-counterfeiting, sensors, and X-ray imaging. Finally, we discuss the challenges related to structural design, mechanistic understanding, and stability, along with perspectives on future opportunities for OIMHs. Full article

Fine powders of erbium niobate-tantalates ErNb_xTa_1−xO₄ (x = 0; 0.1; 0.3; 0.5; 0.7; 0.9; 1) have been synthesized by the liquid-phase method in this study. Ceramic samples have been prepared using conventional sintering from these powders. Rietveld refinement of XRD patterns of polycrystals determined the phase composition and clarified the parameters of the phase structure of ErNb_xTa_1−xO₄ solid solutions depending on the Nb/Ta ratio. The morphological features of the microstructure of erbium niobate-tantalate ceramics have been studied. Their mechanical properties, strength characteristics (Young’s modulus, microhardness) and critical stress intensity factor of the first kind K_IC have been estimated. The photoluminescent properties of ceramic solid solutions of erbium niobate-tantalates depending on the composition have been studied. Dark and photoinduced toxicity of finely dispersed ErNbO₄ powders have been studied in relation to Gram-positive, Gram-negative and spore-forming microorganisms. The best indicators of antibacterial activity of ErNbO₄ have been demonstrated in relation to Gram-positive cells of Micrococcus sp. The discovered properties open up the possibility of not only traditional use as functional materials, but also the use of these materials for disinfection of surfaces, water and biological tissues. Full article

Understanding how solvents influence the luminescence behavior of Cu(I) complexes is crucial for designing advanced optical sensors. This study reports the synthesis, structures and photophysical investigation of an 8-hydroxyquinoline-functionalized 1H-imidazo[4,5-f][1,10]phenanthroline ligand, ipqH₂, and its four Cu(I) complexes with diphosphine co-ligands. Photoluminescence studies demonstrated distinct solvent-dependent excited-state mechanisms. In DMSO/alcohol mixtures, free ipqH₂ exhibited excited-state proton transfer (ESPT) and enol-keto tautomerization, producing dual emission at about 447 and 560 nm, while the complexes resisted ESPT due to hydrogen bond blocking by PF₆⁻ anions and Cu(I) coordination. In DMSO/H₂O, aggregation-caused quenching (ACQ) and high-energy O–H vibrational quenching dominated, but complexes 1 and 2 showed a significant red-shifted emission (569–574 nm) with high water content due to solvent-stabilized intra-ligand charge transfer and metal-to-ligand charge transfer ((IL+ML)CT) states. In DMSO/DMF, hydrogen bond competition and solvation-shell reorganization led to distinct responses: complexes 1 and 3, with flexible bis[(2-diphenylphosphino)phenyl]ether (POP) ligands, displayed peak splitting and (IL + ML)CT redshift emission (501 ⟶ 530 nm), whereas complexes 2 and 4, with rigid 9,9-dimethyl-4,5-bis(diphenylphosphino)-9H-xanthene (xantphos), showed weaker responses. The flexibility of the diphosphine ligand dictated DMF sensitivity, while the coordination, the hydrogen bonds between PF₆⁻ anions and ipqH₂, and water solubility governed the alcohol/water responses. This work elucidates the multifaceted solvent-responsive mechanisms in Cu(I) complexes, facilitating the design of solvent-discriminative luminescent sensors. Full article