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Preparation of Nb2O5-decorated hierarchical porous ZnO microspheres with enhanced photocatalytic degradation of palm oil mill effluent
摘要： In the present work, Nb2O5-decorated hierarchical porous ZnO microspheres (ZnO/Nb2O5) were successfully prepared through a facile surfactant-free method. The as-prepared samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV–Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy and Brunauer–Emmett–Teller surface area analyses. Under UV light irradiation, the ZnO/Nb2O5 composites degraded palm oil mill effluent (POME) efficiently and demonstrated much higher photocatalytic activity compared to those of pure ZnO and Nb2O5. The enhanced photocatalytic degradation performance of ZnO/Nb2O5 composites was attributed to the high charge separation efficiency and hydroxyl radical generation ability as verified by the photoluminescence spectra. Phytotoxicity test upon the POME degradation over ZnO/Nb2O5 photocatalysis considerably decreased through the measurement of radicle lengths of Vigna radiata. Moreover, the ZnO/Nb2O5 composites were reused several times without appreciable loss of activity. This work revealed that the as-prepared ZnO/Nb2O5 composites have great potential for practical applications in the field of wastewater treatment.
关键词： Nb2O5-decorated hierarchical porous ZnO microspheres,Photocatalytic degradation,Charge separation efficiency,Palm oil mill effluent,Hydroxyl radical generation
更新于2025-09-10 09:29:36
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Self-assembly of colloidal Poly(St-MMA-AA) core/shell photonic crystals with tunable structural colors of the full visible spectrum
摘要： This study used the copolymer emulsion method to synthesize colloidal monodisperse core/shell microspheres composed of the poly(styrene-co-methyl methacrylate-co-acrylic acid) [Poly(St-MMA-AA)]. Colloidal photonic crystal (CPhC) films have prepared by using polymer composite microspheres and successfully fabricated via natural sedimentation. The synthesized results of polymer composite microsphere exhibited uniform and good morphology. The resultant of CPhC color films demonstrated vividly structural colors due to 3D CPhC nanostructures. The structural colors over full visible spectra could be tuned by controlling the filling factor of crystals and diameter of microspheres according to the Bragg law. Additionally, the structural color of Poly(St-MMA-AA) CPhC films has measured under the standard colorimetric system. This study demonstrated a approach to fabricate tunable structural color for numerous applications.
关键词： Photonic crystals,Polymer microspheres,Structural colors,Colloidal crystals,Self-assembly
更新于2025-09-10 09:29:36
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Synthesis of Urchin-like and Yolk-shell TiO <sub/>2</sub> microspheres with enhanced photocatalytic properties
摘要： The novel urchin-like and yolk-shell titania microspheres (henceforth called UYTMs) with nanowires/microspheres hierarchical structures were successfully synthesized by a synthetic sol-gel and hydrothermal method without using any template. Uniform TiO2 microspheres were firstly prepared by the sol-gel method, and the great monodispersed properties was delicately regulated by using the surfactant of KCl, aniline and a proper amount of water. The urchin-like yolk-shell morphology was further achieved by a NaOH-assisted hydrothermal process, and the diameter and shell thickness of the UYTMs were highly controlled by the concentration of NaOH. The detailed morphology, chemical composition and crystallinity of the UYTMs were systematically characterized by several techniques, and the underlying formation mechanisms was attentively discussed as well. The photodegradation of methylthionine chloride experiments indicated the UYTMs showed much better photocatalytic activity than that of commercial P25. This is mainly because the UYTMs exhibited much more reactive sites, higher adsorption ability and tuned optical absorption behavior owing to their large specific surface area, hierarchical structures and the special hollow yolk-shell structure.
关键词： Titania,NaOH-assisted hydrothermal synthesis,Photocatalytic activity,Yolk-shell,Urchin-like microspheres
更新于2025-09-10 09:29:36
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Vapor-Phase Growth of CsPbBr <sub/>3</sub> Microstructures for Highly Efficient Pure Green Light Emission
摘要： All-inorganic lead halide perovskites have been extensively studied in the past several years due to their superior stability against moisture, oxygen, light, and heat compared with their organic–inorganic counterparts. CsPbBr3 with suitable band gap and ultrahigh photoluminescence quantum yield is a promising candidate for pure green emitter in the backlighting display to fill the so-called “green gap.” Here, vapor-phase growth of CsPbBr3 microspheres is reported for highly efficient pure green light emission. The as-synthesized microspheres exhibit a stronger photoluminescence (PL) intensity with a photoluminescence quantum yield of 75% resulting from the lower energy of longitudinal optical phonons revealed by temperature dependent PL studies. Importantly, with the diameter increasing from 2 to 50 μm the PL peak positions of the microspheres can be readily tuned from 527 to 539 nm, well filling the so-called “green gap.” The red-shift with increasing diameter can be ascribed to the reabsorption process during the photon propagation inside the microspheres. The studies provide a route to improve the photoluminescence quantum yield in all-inorganic lead halide perovskites, but also suggest an alternative approach to achieve the pure green emission for the backlighting display.
关键词： LO phonon,CsPbBr3,microspheres,reabsorption,pure green emission
更新于2025-09-10 09:29:36
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Selective Recognition of Fe(III) in Aqueous Environment over Covalently-Bonded Tb-Complex-Containing Fluorescent Porous Copolymer Microspheres
摘要： An environment-friendly synthesis of a covalently bonded terbium(Tb)-complex-containing monodispersed fluorescent porous copolymer microspheres, and their highly selective detection of Fe3+ are described. The as-made copolymer microspheres exhibit intense green fluorescence originating from Tb ions and high photostability in water. Encouragingly, the fluorescence of the copolymer microspheres can be selectively quenched by trace Fe3+ due to the interaction between Fe3+ and the ligands, which disturbs the coordination structure of Tb-complexes and inhibits the energy transfer from ligands to Tb ions. The intense fluorescence intensity, high fluorescence stability, together with the nanoscale and porous nature of the copolymer microsphere endows them with wide detection range (0–1500 μm) and low detection limit (2.1 μm) for selective recognition of Fe3+ in aqueous environment. This study paves a new pathway for the function of porous copolymer microspheres being used as targeting for biological detection and environmental issues.
关键词： Tb-complex,fluorescence sensors,iron ions,luminescence,polymer microspheres
更新于2025-09-10 09:29:36
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The preparation and photocatalytic performance research of CdSe and wool ball-like GO/CdSe microspheres
摘要： Different morphologies of CdSe and GO (graphene oxide)/CdSe microspheres like wool ball and walnut shape have been made through hydrothermal method using CTAB as surfactant. X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), X-ray energy dispersive spectrometer (EDS), scanning electron microscope (SEM), Raman spectra, and UVevis absorption spectrum, were used to intensively investigate the structures, morphologies, chemical compositions and optical properties of CdSe and GO/CdSe microspheres. The results of XRD revealed that GO/CdSe microspheres have lead-zinc mineral structure. The results of XRD, EDS, XPS and Raman spectra showed that GO/CdSe microspheres were grown on GO sheets. Also UVevis absorption spectrum indicated that GO/CdSe microspheres enhanced absorbance in UV light region and visible light region. Through comparative experiments, the results showed that pH ? 4 is the optimal pH value for degrading Rhodamine B (RhB) solution. To study the photocatalytic performance of GO/CdSe microspheres, we catalyzed the degradation of RhB aqueous solution irradiated by visible light. The photocatalytic results showed that the wool ball-like GO/CdSe microspheres exhibited better photocatalytic activity than rough CdSe.
关键词： GO/CdSe microspheres,Hydrothermal method,Morphologies,GO,Photocatalytic activity
更新于2025-09-10 09:29:36
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Enhanced fluorescent intensity of magnetic-fluorescent bifunctional PLGA microspheres based on Janus electrospraying for bioapplication
摘要： Microspheres with magnetic-fluorescent functions have received attention due to fluorescent tracking and target positioning. To improve the accuracy of optical imaging and the fluorescent tracking of drug release, it is essential to enhance the fluorescent intensity of microparticles. Magnetic-fluorescent bifunctional poly lactic-co-glycolic acid (PLGA) Janus microspheres [PLGA/TbLa3(Bim)12]//[PLGA/Fe3O4] with double chambers were fabricated with the double-needle electrospraying method. The fluorescent drug TbLa3(Bim)12 with dual rare earth ions was encapsulated in one chamber, while Fe3O4 magnetic nanoparticles (Fe3O4 MNPs) were simultaneously encapsulated in another chamber. In comparison, magnetic-fluorescent PLGA composite microspheres PLGA/TbLa3(Bim)12/Fe3O4 were also prepared, which encapsulated fluorescent drugs TbLa3(Bim)12 with dual rare earth (RE) ions and Fe3O4 MNPs in one chamber. The fluorescent intensity at 542 nm of Janus microspheres was about three times higher than that of composite microspheres due to a decrease in contact between fluorescent-labeling RE drug and MNPs. The fluorescent intensities of Janus microspheres with different contents of Fe3O4 MNPs and TbLa3(Bim)12 were investigated. Furthermore, the magnetic properties, thermostability, cell toxicity and hemolytic properties of Janus microspheres were also assayed to conduct a tentative exploration of their bioapplication. The Janus microspheres provide many opportunities for application in biofields such as drug delivery.
关键词： bioapplication,PLGA microspheres,Janus electrospraying,magnetic-fluorescent bifunctional
更新于2025-09-10 09:29:36
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High Optical Energy Storage and Two-Photon Luminescence from Solution-Processed Perovskite-Polystyrene Composite Microresonators
摘要： Optical green emitting microresonators with high values of nonlinearity are desired for high optical up-conversion energy storage and lasing applications. Here we report on the synthesis of benzylammonium lead iodide (BALI) perovskite microcrystals made via anti-solvent diffusion method. The use of polystyrene (PS) matrix helps the growth of environmentally stable BALI nanocrystals as a result of polymer capping. Optimization of the ratio of BALI-PS during the self-assembly process leads to the formation of defect-free composite microspheres. Further, these BALI crystals act as an active material within the microsphere resonators that display whispering gallery modes (WGM). These WGMs are responsible for high optical storage energy of resonators evidenced by their Q-factor as high as ~1180. Two-dimensional finite difference time-domain calculation shows the concentration of the electric field near the microspheres boundary within a small mode volume of 1.83 μm3. Remarkably, BALI-PS composite microresonators and their neat crystals exhibit brilliant two-photon luminescence upon excitation by the infrared fundamental radiation. This simplistic microresonators fabrication technique provides a route towards low-cost non-linear optical microlasers and other optical energy devices useful for various applications.
关键词： non-linear optical properties,perovskite,optical microresonators,polymer microspheres,two-photon emission
更新于2025-09-10 09:29:36
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Microsphere-Assisted Microscopy: From 2D to 3D Super-Resolution Imaging
摘要： Here we present a new unlabelled far field optical imaging technique using microspheres to enhance the lateral resolution in optical microscopy. Both 2D and 3D super-resolution imaging using microspheres are considered, providing results of 2D and 3D imaging of surfaces with vastly improved lateral resolution and nanometric axial resolution for the 3D mode. Results are shown on narrow etched gratings in Si, nanotextured stainless steel surfaces and Ag nanodots. The main results demonstrate improvements of up to 3 times in lateral resolution, showing details of 300 nm for a microscope that would normally have a limit of 850 nm. Microsphere-assisted microscopy is a major new type of far field optical microscopy with great potential for high resolution imaging, characterisation and nanometrology in materials science and the biological sciences.
关键词： simulations,microspheres,super-resolution,unlabelled microscopy,gratings
更新于2025-09-09 09:28:46
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Synthesis of Silica Microspheres—Inspired by the Formation of Ice Crystals—With High Homogeneous Particle Sizes and Their Applications in Photonic Crystals
摘要： Silica microspheres (SMs) must possess the performances of desirable monodispersity, narrow particle size distribution, and high sphericity for preparing photonic crystals (PCs) and other materials such as microspheres reference material, etc. We have adopted the techniques of increasing reactant concentration and raising the temperature to improve the synthesis rate of SMs, gaining inspiration from the formation mechanism of ice crystals. SMs with uniform particle sizes (polydispersity index less than 0.05) and good spherical features were fabricated through homogeneous nucleation. The mathematical relationship between particle sizes of SMs and reactant concentrations is further fitted. High accuracy of the regression equation is verified by an F-test and verification experiment. Highly ordered PCs (the stacking fault is about 1.5%, and the point defect is about 10?3) with dense stacked opal structures have been obtained by self-assembly of SMs. In addition, highly ordered PCs (the stacking fault is about 3%, and the point defect is about 10?3) with non-dense packed opal structure and inverse opal structure were successfully prepared. PCs of inverse opal structure were used to examine their response characteristics to identify ethanol, exhibiting good performance. Our research may provide significant inspiration for the development of other sorts of microspheres.
关键词： photonic crystals,silica microspheres,homogeneous nucleation,self-assembly
更新于2025-09-09 09:28:46