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In Situ Generation of AgI Quantum Dots by the Confinement of A?Supramolecular Polymer Network: A Novel Approach for Ultrasensitive Response
摘要： Currently, it is difficult to realize environmentally friendly synthesis of zeolites due to the use of the solvent. Therefore, it is of great importance to realize zeolite synthesis from iron ore tailings (IOTs) by a solvent-free method. In this work, in situ formed zeolite crystals are self-assembled and IOTs are converted into hierarchically porous ZSM-5. After that, the products prepared are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and nitrogen adsorption. The results demonstrate that the samples show well-defined crystallinity and have micro-/mesoporous structures. The BET surface area is estimated to be 319.809 m2 g?1 and the external surface area is 92.693 m2 g?1, which indicate the as-synthesized ZSM-5 is a good hierarchically porous material. This work provides a reference for green synthesis of hierarchically porous ZSM-5 from IOT.
关键词： Hierarchical structure,Iron ore tailings,Solvent-free method,ZSM-5
更新于2025-11-14 15:15:56
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Fabrication of highly efficient and stable hole‐transport material free perovskite solar cells through morphology and interface engineering: full ambient process
摘要： Carbon based hole-transport material (HTM) free perovskite solar cells (PVSCs) with low cost and high stability have attracted research interests. Here, we report a facile way to improve the performance of HTM free PVSCs by employing two strategies: firstly, adding a small amount of tetrahydrofuran (THF) in lead iodide (PbI2)/N,N-dimethylformamide (DMF) solution to improve the quality of perovskite film; secondly, introducing an ultra-thin Al2O3 film at the interface of TiO2/perovskite to reduce charge recombination. THF is found to facilitate the formation of homogenous perovskite films with better coverage, while the ultra-thin Al2O3 layer will avoid the direct contact of TiO2 with CH3NH3PbI3. The Al2O3 layer can effectively block holes and prevents charge recombination, thus lead to a dramatic improvement of open circuit voltage and fill factor in PVSCs. Moreover, our PVSCs show excellent long term stability with no degradation for 1000 hours under ambient conditions. We provide a facile way for the future commercialization of efficient low-cost HTM-free PVSCs.
关键词： hole conductor free,interface engineering,perovskite solar cells,high stability
更新于2025-10-22 19:40:53
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Eumelanin for Nature‐Inspired UV‐Absorption Enhancement of Plastics
摘要： In the human body, the black-brown biopigment eumelanin blocks the harmful ultraviolet (UV) radiation. In the plastics industry, additives are often added to polymers to increase their UV-absorption properties. We herein report an assessment of the biopigment eumelanin as a nature-inspired additive for plastics to enhance their UV-absorption. Since eumelanin is produced by natural sources and is non-toxic, it is an interesting candidate in the field of sustainable plastic additives. In this work, eumelanin-including films of commercial ethylene-vinyl acetate copolymer (EVA), a plastic used for packaging applications, were obtained by melt-compounding and compression molding. The biopigment dispersion in the films was improved by means of the Melanin Free Acid treatment (MFA). It was observed that eumelanin amounts as low as 0.8% wt. cause an increase of the UV absorption, up to one order of magnitude in the UVA range. We also evaluated the effect of eumelanin on the thermal and photostability of the films: the biopigment proved to be double-edged, working both as UV-absorption enhancer and photo-prooxidant, as thermogravimetric analysis (TGA) and infrared (IR) spectroscopy revealed.
关键词： Eumelanin,Packaging,Melanin Free Acid,UV-absorbers,Ethylene-vinyl acetate copolymer,UV-aging
更新于2025-10-22 19:40:53
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Microfluidics Integrated Lithography-Free Nanophotonic Biosensor for the Detection of Small Molecules
摘要： Currently, labeling techniques are mostly used to study the binding kinetics of small molecules and their detection (molecular weights <500 Daltons) at low analyte concentrations. However, the fluorescent tags used in this method for conjugation may modify or prevent the functionality of the targeted molecules. Although label-free techniques provide more accurate quantitative and kinetic measurements by monitoring the binding of analytes in their usual forms, the monitoring of small molecule binding at lower concentrations is still impossible using conventional refractometric sensing devices. Here, a label-free and cost-effective technique is demonstrated for the detection of ultralow molecular weight biomolecules such as biotin (244 Daltons) at very low concentrations. This extreme sensitivity is realized by utilizing the phase singularity feature of lithography-free nanophotonic cavities. The proposed four-layered metal-dielectric-dielectric-metal asymmetric Fabry–Perot cavity exhibits point-of-darkness and phase singularity at the Brewster angle. Since the singular phase behavior depends on the topology of the cavity surface, it is very challenging to realize singular phase in reflection mode for a microfluidics integrated nanophotonic cavity. To overcome this issue, a specially designed polymethylmethacrylate microfluidic channel is integrated with the cavity.
关键词： flat-optics,small biomolecules,Fabry–Perot cavities,lithography-free,label-free optical biosensors,biosensors
更新于2025-09-23 15:23:52
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Fast-curing halogen-free flame-retardant epoxy resins and their application in glass fiber-reinforced composites
摘要： A series of novel fast-curing halogen-free flame-retardant epoxy resins were formulated and used to prepare glass fiber-reinforced composites. Dynamic mechanical analysis showed that the optimized epoxy system could be completely cured in 0.5 h at 150°C and had a glass transition temperature (Tg) of above 130°C. The optimized epoxy system was also used as matrix resin to make glass fiber prepregs and composite panels. The flame-retardant properties of the glass fiber-reinforced composites were investigated, including the limiting oxygen index (LOI) and flaming, smoke and toxicity properties. The glass fiber-reinforced composite had good flame retardancy with a UL-94 V-1 rating and high LOI of ≥36%. More significantly, the composite based on the flame-retardant epoxy resin showed lower smoke density compared with those based on phenolic resins. Finally, the glass fiber prepregs were used to fabricate honeycomb sandwich composites. The peel strength of the epoxy-based composites was almost twice that of the composites based on phenolic resin.
关键词： prepregs,fast cure,glass fiber-reinforced composites,halogen-free flame retardancy,epoxy resins
更新于2025-09-23 15:23:52
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Sub-5 nm Ultra-Fine FeP Nanodots as Efficient Co-Catalysts Modified Porous g-C <sub/>3</sub> N <sub/>4</sub> for Precious-Metal-Free Photocatalytic Hydrogen Evolution under Visible Light
摘要： Sub-5 nm ultra-fine iron phosphide (FeP) nano-dots-modified porous graphitic carbon nitride (g-C3N4) heterojunction nanostructures are successfully prepared through the gas-phase phosphorization of Fe3O4/g-C3N4 nanocomposites. The incorporation of zero-dimensional (0D) ultra-small FeP nanodots co-catalysts not only effectively facilitate charge separation but also serve as reaction active sites for hydrogen (H2) evolution. Herein, the strongly coupled FeP/g-C3N4 hybrid systems are employed as precious-metal-free photocatalysts for H2 production under visible-light irradiation. The optimized FeP/g-C3N4 sample displays a maximum H2 evolution rate of 177.9 μmol h?1 g?1 with the apparent quantum yield of 1.57% at 420 nm. Furthermore, the mechanism of photocatalytic H2 evolution using 0D/2D FeP/g-C3N4 heterojunction interfaces is systematically corroborated by steady-state photoluminescence (PL), time-resolved PL spectroscopy, and photoelectrochemical results. Additionally, an increased donor density in FeP/g-C3N4 is evidenced from the Mott-Schottky analysis in comparison with that of parent g-C3N4, signifying the enhancement of electrical conductivity and charge transport owing to the emerging role of FeP. The density functional theory calculations reveal that the FeP/g-C3N4 hybrids could act as a promising catalyst for the H2 evolution reaction. Overall, this work not only paves a new path in the engineering of monodispersed FeP-decorated g-C3N4 0D/2D robust nanoarchitectures but also elucidates potential insights for the utilization of noble-metal-free FeP nanodots as remarkable co-catalysts for superior photocatalytic H2 evolution.
关键词： transition-metal phosphides,g-C3N4,co-catalysts,precious-metal-free,photocatalytic H2 production
更新于2025-09-23 15:23:52
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Performance Limits of FSO Based SAC-OCDMA System Under Weather Conditions
摘要： In this paper, the Spectral Amplitude Coding Optical Code Division Multiple Access (SAC-OCDMA) is investigated in Free Space Optics (FSO) using Zero Cross Correlation (ZCC) codes to evaluate its performance limits in terms of link range. The system is analyzed under clear, haze, moderate fog and dense fog weather conditions. This system has been evaluated numerically and by simulation analysis by maintaining the transmitted power at 10 dBm, for safety reason, according to International Telecommunication Union (ITU) and minimum acceptable BER of 10–9. The simulation results shown that the present system can transmit 622 Mbps/1 Gbps up to maximum link range of 1450 m/1100 m and 61 m/54 m under clear and dense fog conditions, respectively.
关键词： fog,haze,free space optic (FSO),spectral amplitude coding optical code division multiple access (SAC-OCDMA),zero cross-correlation (ZCC)
更新于2025-09-23 15:23:52
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Two- and Three-Photon Partial Photoionization Cross Sections of Li+, Ne8+ and Ar16+ under XUV Radiation
摘要： In this work, we present the photon energy dependence of the two- and three-photon cross sections of the two-electron Li+, Ne8+ and Ar16+ ions, following photoionization from their ground state. The expressions for the cross sections are based on the lowest-order (non-vanishing) perturbation theory for the electric field, while the calculations are made with the use of an ab initio configuration interaction method. The ionization cross section is dominated by pronounced single photon resonances in addition to peaks associated with doubly excited resonances. In the case of two-photon ionization, and in the non-resonant part of the cross section, we find that the 1D ionization channel overwhelms the 1S one. We also observe that, as one moves from the lowest atomic number ion, namely Li+, to the highest atomic number ion, namely Ar16+, the cross sections generally decrease.
关键词： free-electron laser,X-ray radiation,cross sections,lowest-order perturbation theory,multiphoton ionization
更新于2025-09-23 15:23:52
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Continuous Photocatalysis Based on Layer-by-layer Assembly of Separation-free TiO?/Reduced Graphene Oxide Film Catalysts with Increased Charge Transfer and Active-site
摘要： Although photodegradation is the most widely studied method for the purification of water, the challenges for the post-separation of catalysts from water prevent the technique from practical applications. In this study, separation-free TiO2/reduced graphene oxide (rGO) multilayer films were first prepared through layer-by-layer (LbL) assembly of TiO2 and graphene oxide (GO) on quartz slides, followed by a reduction of the assembled GO to rGO. For a proof-of-concept demonstration of novel continuous photocatalysis with potential for scale-up production, these quartz slides with TiO2/rGO film catalysts were further assembled into slide arrays in a home-made rectangular quartz reactor and a model pollutant Rhodamine B (RhB) solution was circularly pumped over the slide surface under UV irradiation. It was found that the as-prepared TiO2/rGO film catalysts show excellent enhanced continuous photocatalytic activity, with a photodegradation rate constant of 2.6 × 10-2 min?1 exceeding the corresponding TiO2/GO and TiO2 (TiO2/PSS) samples by a factor of 11.3 and 13, respectively. The enhanced performance is attributed to the formation of Ti-O-C bonds in film catalysts bridging TiO2 and rGO to enable efficient charge separation and transfer, the Ti-O-C bond bridged electron transfer leading to increase in ·O2- active sites on the rGO surface, and the porous-like multilayer structure. The recycling experiments showed the film catalysts are stable and could be reused with the same efficiency for at least 8 cycles.
关键词： layer-by-layer,continuous photocatalysis,separation free,graphene,film
更新于2025-09-23 15:23:52
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Seed Free Growth of Aligned ZnO Nanowire Arrays on AZO Substrate
摘要： In the absence of commonly used seed layer, we can still successfully synthesized aligned ZnO nanowire arrays by the hydrothermal method. By using aluminum-doped zinc oxide (AZO) glass as a substrate, high-density and vertically aligned ZnO nanowires were synthesized directly on the substrate in the absence of the ZnO seed layer. The current-voltage curve indicated that the sample grown on AZO glass substrate in the absence of seed layer possesses better conductivity than that synthesized on FTO glass substrate with ZnO seed layer. Thus, a simplified, seed-free and low-cost experimental protocol was reported here for large-scale production of high quality ZnO nanowire arrays with promoted conductivity.
关键词： conductivity,ZnO nanowire arrays,seed layer free,AZO substrate
更新于2025-09-23 15:23:52