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X-ray scintillator Gd2O2S:Tb3+ materials obtained by a rapid and cost-effective microwave-assisted solid-state synthesis
摘要： In this work, the microwave-assisted solid-state (MASS) synthesis is reported as a rapid, cost-effective and environmental-friendly way to prepare Gd2O2S:Tb3+ X-ray scintillation standards. The preparation procedure employs active charcoal as the microwave susceptor, using a domestic microwave oven without a setup for special gases. The MASS method drastically reduced the synthesis time and energy consumption (up to 97% in nominal power) over previous reports using conventional solid-state methods. A single-step synthesis of 10 min is enough to yield highly crystalline powders starting from Gd2O3 and Tb4O7 precursors and elemental sulfur. In order to obtain 100% pure materials with superior scintillation efficiency, two microwave treatments of 25 min each are required. Due to the reducing CO atmosphere generated in situ by the active charcoal during the microwave synthesis, no Tb4+ impurity was found according to Synchrotron Radiation X-ray Absorption (SR-XAS) experiments. Spectroscopic studies were carried out using SR Vacuum-Ultraviolet (VUV) photoluminescence and SR X-ray Excited Optical Luminescence (XEOL). The material prepared by two-step synthesis exhibited a better scintillation performance owing to higher crystal purity and emission intensity, presenting versatility for technological applications such as X-ray imaging and scintillation bio-probing.
关键词： Synchrotron Radiation,Gd2O2S:Tb3+,Microwave-assisted solid-state synthesis,X-ray scintillation
更新于2025-09-23 15:21:01
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Solar Cells with High Short Circuit Currents Based on CsPbBr <sub/>3</sub> Perovskite-Modified ZnO Nanorod Composites
摘要： 3-D all-inorganic perovskite solar cells have been built using vertically aligned conductive zinc oxide nanorods as the electron transport layer and optical waveguide. Yttrium doping improved the conductivity and hence the electron transportation of the ZnO achieving a threefold improvement of the solar cell efficiency. The vertically aligned nanorods act as optical waveguides and a scaffold, which improved photoabsorption of the perovskite semiconductor by increasing layer thickness. Our device structure was completed with an exfoliated multilayer graphite back contact for effective hole-extraction. The ZnO was most significantly modified by nanometre scale coatings of TiO2 in order to passivate the surface and reduce charge recombination, as measured by photoluminescence spectroscopy. This led to greatly improved charge transfer. This strategy led to an overall nine times enhancement in the solar cell efficiency, yielding a competitive top value of 5.83%. More importantly, the all-inorganic solar cells demonstrated excellent stability, showing no decline in initial performance after 1000 hour storage in ambient conditions. This work presents yttrium doped ZnO nanorods as a suitable replacement for mesoporous TiO2, achieving a high short circuit current of 10.5 mA cm-2 for CsPbBr3 perovskite devices.
关键词： Graphite,ambient synthesis,Inorganic perovskite,TiO2 coating,ZnO nanorods
更新于2025-09-23 15:21:01
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A three-dimensional steerable optical tweezer system for ultracold atoms
摘要： We present a three-dimensional steerable optical tweezer system based on two pairs of acousto-optic deflectors. Radio frequency signals used to steer the optical tweezers are generated by direct digital synthesis, and multiple time averaged cross beam dipole traps can be produced through rapid frequency toggling. We produce arrays of ultracold atomic clouds in both horizontal and vertical planes and use this to demonstrate the three-dimensional nature of this optical tweezer system.
关键词： ultracold atoms,direct digital synthesis,optical tweezer,acousto-optic deflectors,cross beam dipole traps
更新于2025-09-23 15:21:01
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[Springer Series on Polymer and Composite Materials] Polymer/POSS Nanocomposites and Hybrid Materials (Preparation, Properties, Applications) || Synthesis Routes of POSS
摘要： The study of the chemistry of materials containing Si–O bonds was in the past mainly applied to both inorganic silica and minerals or to organic silicones ?eld in which the R2SiO unit dominates. However, in the last decade, the ?eld of silsesquioxane chemistry with general composition RSiO3/2 has grown dramatically and many structures have been proposed in the literature. The idea of this chapter is to make an overview of the main synthetic approaches used to prepare completely and partially polyhedral oligomeric silsesquioxanes (POSS), highlighting the advantages and the weakness of each procedure. A brief description of the characterization techniques used to analyze the physicochemical properties of POSS was also carried out.
关键词： Hydrosilylation,Functionalization,Close-cage POSS,POSS synthesis,Open-cage POSS,Polyhedral oligomeric silsesquioxanes,Corner capping,Cleavage
更新于2025-09-23 15:21:01
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Citrus limetta Organic Waste Recycled Carbon Nanolights: Photo-electro catalytic, Sensing and Biomedical Applications
摘要： The present work reports green route-waste recycled carbon nanolights i.e. carbon dots (GCDs) synthesized via a facile one-step pyrolysis method from Citrus limetta waste pulp. The size of these obtained pristine GCDs is ~4-7 nm (HR-TEM), with high optical and structural quality as revealed by FT-IR and Raman spectroscopic analysis. They exhibit the highest quantum yield of 63.3 % over other similar green synthesized GCDs, favourable for many applications. Further, we demonstrate the multifunctional aspects of these synthesized GCDs for photo-electrochemical water splitting, photocatalytic methylene blue degradation, Fe(III) ions sensing, bactericidal activity (against E. coli and S. aureus), and bioimaging with excellent performance. The visible light active characteristic of GCDs is observed to achieve an efficient current density of ~6 mA/cm2 towards water splitting. This study demonstrates the waste to wealth potential of recycled waste derived GCDs in wide range of application domains.
关键词： GCDs,Biomedical,Green Synthesis,Waste Recycle,Dye Degradation,Water Splitting
更新于2025-09-23 15:21:01
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Synthesis of Phenylpyridine Iridium(III) Complexes with N-Heterocyclic Carbene as Ancillary Ligands
摘要： In this study, [Ir(2,4-F2ppy)2(2-(1,2,4-triazol-1-yl)pyridine)]PF6 (C1), [Ir(2,4-F2ppy)2(2-(2-(4-dimethylbenzyl)-1,2,4-triazol-1-yl)pyridine)]PF6 (C2) and [Ir(2,4-F2ppy)2(2(2-hexyl-1,2,4-triazol-1-yl)pyridine)]PF6 (C3) complexes were successfully synthesised by refluxing the mixture of dichloro-bridged iridium(III) dimer, [Ir(2,4-F2ppy)2(μ-Cl)]2 and corresponding triazolium salt containing N-heterocyclic carbene (NHC) as ancillary ligands. 1H NMR of all complexes display well-resolved signals between 10.00-5.00 ppm assign to proton at the aromatic region for penylpyridine and pyridyltriazole. Spectra of C2 and C3 also display signals at aliphatic region (singlets) between 0.80-1.50 ppm that proved the presence of methylbenzyl and hexyl substituent on the pyridyltriazole ring. In addition, IR analysis reported the presence of C=C and C=N stretching of pyridine at range 1570-1470cm-1 and C-H stretching of aromatic pyridine at 2990-3080cm-1. Besides, UV-Vis absorption data showed that the low-energy metal-to-ligand charge-transfer (MLCT) band in C2 (364 nm) is significantly blue-shifted compared to C1 (375 nm) and C3 (381 nm). Overall, this study reported the synthesis and spectroscopic study of phenylpyridine Ir(III) complexes with various types of pyridyltriazole (NHC ancillary ligands).
关键词： Phenylpyridine Iridium(III) Complexes,Spectroscopic Study,N-Heterocyclic Carbene,Ancillary Ligands,Synthesis
更新于2025-09-23 15:21:01
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Enhanced photocatalytic activity based on TiO <sub/>2</sub> hollow hierarchical microspheres/reduced graphene hybrid
摘要： A novel TiO2 hollow hierarchical microspheres/reduced graphene oxide (TiO2 HHMs/rGO) hybrid was prepared by a facile and efficient two-step solvothermal synthesis method. The TiO2 HHMs with the size ～500 nm were uniformly distributed on the surface of rGO nanosheets. The as-prepared TiO2 HHMs/rGO hybrid is stable and exhibits a significantly higher photocatalytic activity (97.8%) for 40 ml of 10 mg/Rhodamine B (RhB) solution than that of the pure TiO2 microspheres (75.2%) and Degussa P25 (53.6%). The rGO nanosheet acts as a microelectrode for rapid accepting and separating the photogenerated electron on surface, which effectively slow the recombination rate of electrons and holes, and then effectively enhance the photocatalytic activity of the hybrid. The as-prepared novel TiO2 HHMs/rGO hybrid shows great promising for practical photocatalytic applications.
关键词： TiO2 hollow hierarchical microspheres/reduced graphene oxide (TiO2 HHMs/rGO) hybrid,enhancement,photocatalytic activity,two-step solvothermal synthesis
更新于2025-09-23 15:21:01
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{0 0 1}-Facet-Exposed Ag <sub/>4</sub> V <sub/>2</sub> O <sub/>7</sub> Nanoplates: Additive-Free Hydrothermal Synthesis and Enhanced Photocatalytic Activity
摘要： The synthesis of silver pyrovanadate, Ag4V2O7, nanoplates with exposed {0 0 1}-facets by a facile, additive-free hydrothermal method was described in this paper. The photocatalytic activity of rhodamine B over Ag4V2O7 samples under solar light irradiation was also evaluated. By using an equimolar mixture of NH4VO3 and AgNO3 with the presence of a suitable amount of ammonia, Ag4V2O7 nanoplates were obtained readily and purely at temperatures from 100 to 140°C for 4 h. The c-axis orientation growth of Ag4V2O7 nanoplates occurred and increased monotonously with temperatures in the range of over 100 up to 140°C. Further increase in hydrothermal temperature up to 220°C, the Ag4V2O7 phase no longer existed and the β-AgVO3 phase was formed instead. The photocatalytic activity of the optimized Ag4V2O7 sample comprising {0 0 1}-facet-exposed nanoplates with the highest degree of orientation was significantly higher than that of the random-oriented sample. The effects of using ammonia as a complexing agent on the structure, microstructure, texture, exposed facet, and photocatalytic activity of Ag4V2O7 samples were also investigated for the first time.
关键词： photocatalytic activity,hydrothermal synthesis,Ag4V2O7,rhodamine B,nanoplates,solar light irradiation
更新于2025-09-23 15:21:01
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Insights into the Synthesis Mechanism of Ag <sub/>29</sub> Nanoclusters
摘要： The current understanding of the synthesis mechanisms of noble metal clusters is limited, in particular for Ag clusters. Here, we present a detailed investigation into the synthesis process of atomically monodisperse Ag29 clusters, prepared via reduction of AgNO3 in the presence of dithiolate ligands. Using optical spectroscopy, mass spectrometry and X-ray spectroscopy, it was determined that the synthesis involves a rapid nucleation and growth to species with up to a few hundred Ag atoms. From these larger species, Ag29 clusters are formed and their concentration increases steadily over time. Oxygen plays an important role in the etching of large particles to Ag29. No other stable Ag cluster species are observed at any point during the synthesis.
关键词： synthesis mechanism,Ag29 nanoclusters,optical spectroscopy,X-ray spectroscopy,mass spectrometry
更新于2025-09-23 15:21:01
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Combustion synthesis and photoelectrochemical characterization of gallium zinc oxynitrides
摘要： We report a rapid combustion synthesis method for producing band gap tunable gallium zinc oxynitrides, a material of interest for water splitting applications. By varying the ratio of zinc and gallium, we can tune the band gap from 2.22 to 2.8 eV. Furthermore, nitrogen can be incorporated up to nearly 50% via replacement of oxygen without the need for high temperatures or an additional ammonolysis step. X-ray photoelectron spectroscopy (XPS) and EDX analysis suggests a preferential segregation of Zn to the surface of the as-synthesized particles, though the surface Ga/Zn molar ratio in the as-synthesized particles is correlated with the Ga/Zn molar ratio of the precursor materials. Photoelectrochemical measurements show that the oxynitride powders are photoactive under both AM1.5 and visible-only (k . 435 nm) irradiation. Hydrogen and oxygen were both evolved in half-reaction experiments under simulated AM1.5 irradiation without externally applied bias, although addition of an OER catalyst did not enhance the rate of oxygen formation, suggesting that intra- and interparticle recombination are signi?cant.
关键词： water splitting,photoelectrochemical,gallium zinc oxynitrides,band gap tuning,combustion synthesis
更新于2025-09-23 15:21:01