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The luminescent properties of GdAlO<SUB align="right">3:Tb<SUP align="right">3+</SUP> phosphors based on molten salts addition
摘要： The (Gd1–xTbx)AlO3 (x = 0–0.12) were obtained through ammonium bicarbonate co-precipitation technology. The pure-phase (Gd1–xTbx)AlO3 with good dispersion could be obtained at relatively lower temperature of 1,000°C. Under optimum UV excitation into 275 nm, the photoluminescence (PL) spectra display a series of 5D4–7FJ transitions of Tb3+ in (Gd1–xTbx)AlO3 system with the strongest green emission at ~546 nm. The overlapping between 8S7/2–6IJ intra f-f transition of Gd3+ and 4f8–4f75d1 transition of Tb3+ at 275 nm suggesting the Gd3+ → Tb3+ energy transfer, and the quenching contents of Tb3+ was found to be ~10 at%. The luminescent property of GdAlO3:Tb3+ phosphor could be further improved with molten salt incorporation. The optimal composition of molten salts was determined to be the mixture of NaCl/Na2SO4 (5 wt% NaCl), and the mass ratio of mixture molten salts to precursor was 2:1. The relationship between the luminescent property and molten salts composition were studied in detail.
关键词： energy transfer,GdAlO3:Tb3+ phosphor,molten salts,luminescent property
更新于2025-09-23 15:22:29
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AgCl/Ag/LaFeO3 heterojunction with a prolonged charge lifetime and enhanced visible light catalytic property
摘要： In this study, uniform mesoporous three–dimensional LaFeO3 with diameter of 2–3 μm was prepared by a hydrothermal process and monodispersed AgCl was then decorated on the surface of the LaFeO3 to form AgCl/Ag/LaFeO3 heterojunction via a facile precipitation–deposition process. The e?ects of the proportions employed in the preparation of the heterojunction on the structural, crystallinity, surface areas, and optical properties of AgCl/Ag/LaFeO3 were systematically studied, which showed that the AgCl/Ag/LaFeO3 heterojunction had a strong hybrid–junction structure, suitable absorption edge, and many exposed surface sites. The AgCl/Ag/LaFeO3 heterojunction had a strong catalytic activity during the degradation of methylene blue and phenol under visible light. The results demonstrated that the AgCl/Ag/LaFeO3 heterojunction had a more intense photocurrent response and smaller surface resistance than both AgCl and LaFeO3. The enhanced photocatalytic ability was attributed to the formation of heterojunctions between AgCl and LaFeO3, which suppressed the recombination of photogenerated electron–hole pairs. Our results may facilitate the rational design of highly e?cient heterogeneous heterojunctions for the removal of organic pollution.
关键词： AgCl/Ag/LaFeO3,Hybrid–junction structure,Charge transfer property,Visible light
更新于2025-09-23 15:22:29
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Five new coordination polymers of s- and d-block metals: Structural diversities, magnetic properties and luminescence
摘要： In order to explore the metal ions-controlled syntheses of coordination polymers (CPs), the temperature and solvent ratio were fixed in the reaction processes. By selecting a series of s- and d-block metal ions, five new CPs, [ZnL0.5(H2O)2]n (1), [CoL0.5(H2O)2]n (2), [Mn(H2L)(H2O)2]n (3), [Ca(H2L)(H2O)2]n (4) and [Ba(H2L)(H2O)2]n (5), have been synthesized by employing a less-investigated oxalamide N,N′-bis(4-phthalic acid) (H4L) ligand. H4L shows very versatile coordination modes and leads to various frameworks, including isomorphous 2D grid-like layer based on M2O2 cores for 1 and 2, isomorphous 4-connected 3D PtS frameworks based on 1D [M(CO2)2]n chains for 3 and 4, and a 2D wave-like layer based on [BaO3]n chains for 5.2 and 3 reveal the antiferromagnetic and ferromagnetic properties, respectively, while 1, 4 and 5 possesses strong solid state luminescence.
关键词： Luminescence,Crystal structure,Crystal engineering,Coordination polymer,Magnetic property
更新于2025-09-23 15:22:29
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Nanoscopic Spotlight in a Spindle Semiconductor Nanowire
摘要： Theoretically, no matter how thin a nanowire is, it can transport light in the form of an evanescent field. However, in practice, the low propagation efficiency induced by complex dissipation makes light transport difficult to realize when the nanowire is distinctly thinner than ~λ/2. Accordingly, nanowire photonics research at such a scale is limited. Herein, light propagation was achieved in a very thin spindle nanowire (diameter below 70 nm), in which a nanoscopic spotlight formed. The nanowire output a maximum emission in the transverse dimension as small as ~53 nm. The finite-difference time-domain (FDTD) simulation implied that the increased dimension gradient near the tip induced a maximum leakage of the propagating light at a transverse feature, precisely determined by the intrinsic feature of the nanowire. Moreover, a spectrum splitter phenomenon was observed and demonstrated based on the wavelength-dependent light propagation behavior in such a nanowire. These results contribute to the rational design of nanoscopic near-field illuminant, optoelectric and photobiological probes with improved resolution largely superior to the so-called subwavelength level.
关键词： semiconductors,nanoscopic light,light waveguide,nanowires,photonic property
更新于2025-09-23 15:22:29
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Enhanced Photocatalytic Reduction of Cr(VI) by Combined Magnetic TiO2-Based NFs and Ammonium Oxalate Hole Scavengers
摘要： Heavy metal pollution of wastewater with coexisting organic contaminants has become a serious threat to human survival and development. In particular, hexavalent chromium, which is released into industrial wastewater, is both toxic and carcinogenic. TiO2 photocatalysts have attracted much attention due to their potential photodegradation and photoreduction abilities. Though TiO2 demonstrates high photocatalytic performance, it is a difficult material to recycle after the photocatalytic reaction. Considering the secondary pollution caused by the photocatalysts, in this study we prepared Ag/Fe3O4/TiO2 nanofibers (NFs) that could be magnetically separated using hydrothermal synthesis, which was considered a benign and effective resolution. For the photocatalytic test, the removal of Cr(VI) was carried out by Ag/Fe3O4/TiO2 nanofibers combined with ammonium oxalate (AO). AO acted as a hole scavenger to enhance the electron-hole separation ability, thereby dramatically enhancing the photoreduction efficiency of Cr(VI). The reaction rate constant for Ag/Fe3O4/TiO2 NFs in the binary system reached 0.260 min?1, 6.95 times of that of Ag/Fe3O4/TiO2 NFs in a single system (0.038 min?1). The optimized Ag/Fe3O4/TiO2 NFs exhibited high efficiency and maintained their photoreduction efficiency at 90% with a recyclability of 87% after five cycles. Hence, taking into account the high magnetic separation behavior, Ag/Fe3O4/TiO2 NFs with a high recycling capability are a potential photocatalyst for wastewater treatment.
关键词： magnetic property,reusable,photoreduction,photocatalyst,TiO2
更新于2025-09-23 15:22:29
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Spectroscopic Properties of Er3+-Doped Particles-Containing Phosphate Glasses Fabricated Using the Direct Doping Method
摘要： The effect of the incorporation of Er2O3-doped particles on the structural and luminescence properties of phosphate glasses was investigated. A series of different Er2O3-doped TiO2, ZnO, and ZrO2 microparticles was synthesized using soft chemistry and then added into various phosphate glasses after the melting at a lower temperature than the melting temperature. The compositional, morphological, and structural analyses of the particles-containing glasses were performed using elemental mapping by field emission-scanning electron microscopy (FE-SEM) with energy dispersive x-ray spectrometry (EDS) and x-ray diffraction (XRD). Additionally, the luminescence spectra and the lifetime values were measured to study the influence of the particles incorporation on the spectroscopic properties of the glasses. From the spectroscopic properties of the glasses with the composition 50P2O5-40SrO-10Na2O, a large amount of the Er2O3-doped particles is thought to dissolve during the glass melting. Conversely, the particles were found to survive in glasses with a composition 90NaPO3-(10 ? x)Na2O-xNaF (with x = 0 and 10 mol %) due to their lower processing temperature, thus clearly showing that the direct doping method is a promising technique for the development of new active glasses.
关键词： oxyfluoride phosphate glass,direct particle doping,Er2O3-doped particles,Er3+ luminescence property,phosphate glass
更新于2025-09-23 15:22:29
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Characterization of a novel silicon-containing hybrid polymer by thermal curing, pyrolysis behavior, and fluorescence analysis
摘要： A novel linear silicon-containing hybrid polymer with C C and Si H linkages, diphenyl-dihydroethynyl-silane (DPHES), had been conveniently synthesized and well characterized. The thermal curing, crosslinked structure and pyrolysis behavior were studied by DSC, Fourier transform infrared (FTIR), and Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The results suggest the crosslinked structures consist mainly of phenyl and aromatic fused rings, which are formed through cyclotrimerization, addition reaction, and hydrosilylation reaction. The thermal properties indicate that the crosslinked DPHES exhibits excellent thermal stability with the temperature at 5% weight loss are higher than 572 and 509 (cid:1)C under nitrogen and air atmosphere, respectively. The ?uorescence emission spectra show DPHES and its crosslinked product also have moderate ?uorescence properties, emitting purple light, and visible blue light, respectively, which further veri?ed the structure of DPHES. These results suggest that DPHES has the potential to be used as light-emitting materials with excellent thermal properties.
关键词： silicon-containing hybrid polymer,?uorescence property,pyrolysis behavior,thermal curing
更新于2025-09-23 15:22:29
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Synergetic utilization of photoabsorption and surface facet in crystalline/amorphous contacted BiOCl-Bi2S3 composite for photocatalytic degradation
摘要： Photoabsorption and surface property of semiconductor are two key factors to determine its photocatalytic performance. In this work, BiOCl-Bi2S3 composites composed of Bi2S3 nanoparticles bonded on BiOCl nanoplates enclosed with {001} and {110} crystal facets were synthesized through an in-situ ion exchange method at room temperature. The transformed Bi2S3 made BiOCl-Bi2S3 composites efficient visible light absorption, ensuring the quantity of photoinduced carriers as well as intimate crystalline-amorphous contact interface to benefit the separation of photoinduced carriers. Moreover, BiOCl nanoplates enclosed with {001} and {110} crystal facets can convenient transfer carriers to {001} crystal facets. The photocatalytic performance of BiOCl-Bi2S3 composites was evaluated by the methylene blue photodegradation under visible light irradiation and the results indicate that BiOCl-Bi2S3 composites have good photocatalytic ability due to enhanced light absorption, efficient separation and transfer of carriers. Based on the active species trapping experiments, transient photocurrents, electrochemical impedance spectroscopy and energy band structure, a possible photocatalytic mechanism of methylene blue over the BiOCl-Bi2S3 composites was proposed.
关键词： Surface property,Visible light,BiOCl-Bi2S3,Contact interface,Photocatalytic mechanism,Crystal facet
更新于2025-09-23 15:22:29
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Photocatalytic Self-Cleaning Cotton Fabrics Coated by Cu2(OH)PO4 under VIS/NIR Irradiation
摘要： In the present work, a mild strategy was employed to obtain cotton fabrics (CFs) coated with Cu2(OH)PO4 (CHP) nanoparticles to achieve self-cleaning property. The phytic acid (IP6) assisted method was employed to synthesize nanoparticles (CHP-IP6). The as-prepared coated cotton fabrics were characterized using the following techniques: Fourier-transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The CHP-IP6 coated cotton fabrics showed significant photocatalytic activity, excellent photocatalytic stability, and good discoloration of methylene blue (MB) stains when exposed to sunlight, which could have important applications as tablecloths, household apparels, and industrial workwear.
关键词： photocatalysis,self-cleaning property,Cu2(OH)PO4,cotton fabric
更新于2025-09-23 15:22:29
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Materials containing benzocyclobutene units with low dielectric constant and good thermostability prepared from star-shaped molecules
摘要： With the development of ultralarge-scale integrated circuits, polymers with low dielectric constant and high thermal stability have aroused great interest. We prepared two novel bridged siloxane-based benzocyclobutene (BCB) star-shaped monomers, tetrakis[dimethyl siloxy-4-(10,10-dimethyl-10-ethyl silicon)-benzocyclobutene] (TDSDES-BCB) and tetrakis(hexamethyl siloxane vinyl-benzocyclobutene) (THSV-BCB), and the corresponding resins were obtained by curing. The structures of TDSDES-BCB and THSV-BCB were confirmed by 1H-NMR, 13C-NMR, and 29Si-NMR spectra and time-of-flight mass spectrometry analysis. The curing behavior of these monomers was investigated by Fourier transform infrared spectroscopy and differential scanning calorimetry. The dielectric constant of cured TDSDES-BCB is only 2.43 at 10 MHz (that of THSV-BCB is 2.46). In addition, these resins display high thermal stability: the 5 wt % weight loss temperature of cured TDSDES-BCB is about 467 °C (454 °C for THSV-BCB resin). The excellent low dielectric property is attributable to the free volume created by the star-shaped structure and crosslinked network structure of BCB after curing.
关键词： thermosets,structure–property relationships,resins,dielectric properties,thermal properties
更新于2025-09-23 15:22:29