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A large Stokes shift, sequential, colorimetric fluorescent probe for sensing Cu2+/S2- and its applications
摘要： Copper ions (Cu2+) and sulfide (S2?) are important markers in many physiologies and pathological processes. In this work, a new near-infrared fluorescent probe 1 for colorimetric and sequential detection of Cu2+/S2? was designed and developed. The probe showed a rapid (less than 1 min), highly selective and sensitive response toward copper ions. Notably, the probe could also be applied to detect S2? through reversible formation-separation of complex 1-Cu2+ and CuS with a large Stokes shift of 234 nm. The detection limit for Cu2+ and S2? was found to be 1.8 × 10-8 M and 1.5 × 10-8 M, respectively. Furthermore, the binding stoichiometry between 1 and Cu2+ was found to be 1:1, the binding mode was also demonstrated using density functional theory (DFT) calculations and contrastive compound research. In addition, the probe was successfully applied in real water samples assay for the detection of Cu2+, and the strip papers experiments also showed that probe 1 can be used to detect Cu2+ and S2?.
关键词： DFT calculations,Colorimetric,Near-infrared,Sulfide,Large Stokes shift,Copper ions
更新于2025-09-19 17:15:36
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A series of two-dimensional lanthanide coordination polymers: synthesis, structures, magnetism and selective luminescence detection for heavy metal ions and toxic solvents
摘要： A series of two-dimensional lanthanide coordination polymers: synthesis, structures, magnetism and selective luminescence detection for heavy metal ions and toxic solvents
关键词： lanthanide ions,coordination polymers,luminescence properties,crystal structure,magnetic properties
更新于2025-09-19 17:15:36
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Luminescence Properties of Dy3+ and Sm3+: Potassium Lithium Borate Glass
摘要： The present paper describes the spectral properties of Sm3+ (0.4 mol%) and Dy3+ (0.4 mol%) ions-doped 20Li2O–10K2O–70B2O3 glasses. X-ray diffraction method was use to confirm the amorphous phase of samples. The physical properties have been determined based on UV absorption spectra. The hypersensitive transition of Dy3+ and Sm3+ is found due to transition of (6F11/2,6H9/2) and (6F7/2), respectively. The emission bands of Dy3+: glass has shown around 572 nm, 612 nm and 646 nm; these emissions are attributed to the transitions of 4F9/2 →6H15/2 (yellow), 4F9/2 - 6H13/2 (red) and 4F9/2 -6H11/2 (red). With regard to Sm3+: glass has three emission bands those have been generated from 4G5/2 → 6H5/2 (616 nm), 4G5/2 → 6H 7/2 (660 nm) and 4G5/2 → 6H9/2 (719 nm) transitions. The current results promise several applications in optical fields such as UV-sensor, developing new color light sources and tunable visible lasers.
关键词： physical properties,rare-earth ions,luminescence,Glasses
更新于2025-09-19 17:15:36
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The fabrication and assembly of the beam source for the SPIDER experiment
摘要： The ITER Heating Neutral Beam injector (HNB) will be equipped with a beam source that will provide a negative beam of 40A (H or D). The R&D activities undertaken in Europe to pursue this challenging goal comprise three experiments: -ELISE – the half size ion source experiment operating in IPP Garching -SPIDER – the full size ion source experiment at Neutral Beam Test Facility (NBTF) site in Padua -MITICA - the full size full energy ITER injector prototype being also established at the NBTF The procurement of the beam source for SPIDER started in October 2012, when a contract between Fusion for Energy and Thales, Microwave & Imaging Sub-Systems (as group leader of a Consortium created with CECOM Srl, Galvano-T GmbH and Zanon SpA) was signed. The scope of the contract has been completed in October 2017 with the delivery of the SPIDER beam source at the NBTF site in Padova Italy. A review of the fabrication of the main parts and of the aspects of their assembly is reported in the paper, with a focus on some of the major issue encountered and the achievement of tight alignment tolerances of the accelerator.
关键词： Negative ions,Neutral beam,Beam source
更新于2025-09-19 17:15:36
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On-off-on fluorescent carbon dots from waste tea: Their properties, antioxidant and selective detection of CrO42?, Fe3+, ascorbic acid and L-cysteine in real samples
摘要： In this work, we reported an economical plant-based hydrothermal method for one-pot green synthesis of water-soluble carbon dots (Tea-CDs) by using waste tea extract as a carbon source. The synthesized Tea-CDs were characterized by UV-visible, fluorescence, FT-IR, TEM, XPS and XRD. The Tea-CDs were found to remove hydroxyl and superoxide anion radical in vitro. In addition, the Tea-CDs exhibited bright blue fluorescence under UV-light (λex=365 nm), and the fluorescence could be effectively quenched by CrO4 2- and Fe3+ ions. Meanwhile, the fluorescence of Tea-CDs-CrO4 2- and Tea-CDs-Fe3+ systems could be again easily recovered by ascorbic acid (AA) and L-cysteine (L-Cys). As an on-off-on fluorescent nano-sensor of the Tea-CDs, the sensitive detection of CrO4 2-, Fe3+, AA and L-Cys were all performed, showing that the good linear relationships between fluorescence intensity of Tea-CDs and concentration of all testing samples. Finally, the sensors successfully detected CrO4 2-, Fe3+, AA and L-Cys in commercially available real samples with satisfactory recovery ranges. The prepared sensors offer distinct advantages including low cost, simple handling, good sensitivity and high selectivity.
关键词： carbon dots,waste tea,L-cysteine,ascorbic acid,on-off-on fluorescent nano-sensor,metal ions
更新于2025-09-19 17:15:36
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Eu3+ as a luminescence probe in DNA studies: Structural and conformational implications
摘要： Lanthanide ions are widely used as luminescent probes for structural studies of various biomolecules, including DNA. Latest developments of circularly polarized luminescence (CPL) methodology further boosted interest to luminescence techniques. However, an effect of the lanthanide probes themselves on the DNA structure and conformation was investigated only partially and not for all lanthanides. In the present work, we performed a detailed spectroscopic study of Eu3+ complexes with native double-stranded DNA and compared them to the relevant complexes with single-stranded DNA. We employed infrared (IR), vibrational circular dichroism (VCD) and electronic circular dichroism (ECD) spectroscopic methods to investigate Eu3+ effect on DNA structure and conformational transitions. It was shown that Eu3+ ions can induce significant alteration of the native DNA structure at the concentrations often used in luminescence studies. While no DNA denaturation was observed at these metal ion concentrations, significant unstacking of the base pairs and disordering of the sugar-phosphate backbone, partial appearance of the A-form backbone geometry, and DNA transition into condensed ψ–type form took place. Eu3+ binding to single-stranded DNA was more pronounced than the binding to double-stranded DNA. We detected the main Eu3+ binding sites and determined the metal ion concentration range in which DNA geometry remains largely unaltered. The results obtained in the current study could be used for tuning the luminescence and CPL structural studies of DNA utilizing Eu3+ ions as probes.
关键词： infrared (IR),DNA condensation,lanthanide ions,DNA structure,luminescence probe,vibrational circular dichroism (VCD)
更新于2025-09-19 17:15:36
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Proton beams of laser-hydrogenated metal targets
摘要： In this paper, we report a study on proton beams produced via laser interaction from hydrogenated solid targets useful for the development of new sources devoted to medical applications, such as hadron therapy and isotope production. The hydrogenation of the targets was made before the laser-matter interaction. In this study, we used as solid targets, pure samples of Ti, Ta and Al which in a ?rst phase were treated by laser cleaning (via KrF excimer laser at the irradiance I = 3×107 W/cm2) and then they were exposed to laser irradiation (1500 pulses, I = 3×107 W/cm2) under a constant ?ow of H2 (HiQ Hydrogen 6.0, highly pure). After that, the targets were maintained under H2 ?ow for 5 minutes, in order to promote a further hydrogen adsorption. We report laser ablation measurements performed at ?uences of 1.3, 2.5 and 5.0 J/cm2. The results on hydrogenated targets showed an increase of proton yield of 25% (Ti), 64% (Al) and 550% (Ta), with respect to the corresponding untreated ones.
关键词： Plasma generation (laser-produced, RF, x ray-produced),Ion sources (positive ions, negative ions, electron cyclotron resonance (ECR), electron beam (EBIS)),Accelerator Applications
更新于2025-09-19 17:13:59
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Rare earth ions doped NiO hole transport layer for efficient and stable inverted perovskite solar cells
摘要： Hole transport layer plays a critical role in achieving high performance and stable inverted perovskite solar cells (PSCs). Doping has been proved to be an effective strategy to modify the electrical and optical properties of semiconductor oxides. Herein, rare earths (REs: Ce, Nd, Eu, Tb, and Yb) elements are systemically doped into the NiOx hole transport layer (HTL) via a simple solution-based method. The results demonstrate that the REs doping could considerably modify the compactness, conductivity, and band alignment of the NiOx HTL, leading to the highly improved permanence of the inverted PSCs. The PSCs using 3% Eu:NiOx HTL yielded the optimum power conversion efficiency of 15.06%, relatively improved 23.4% compared with the PSC using pristine NiOx HTL (12.20%). It also demonstrated much better long time stability. The improved photovoltaic properties of the device can be attributed to the more efficient charge extraction and suppressed interfacial recombination rate by the introduction of appropriate REs in the NiOx HTL. This work indicates that RE doping is a very effective and promising strategy to achieve adjustable hole extraction material for high and stable inverted PSCs.
关键词： Rare earth ions,Perovskite solar cells,Doped NiOx film,Inverted planar structure
更新于2025-09-19 17:13:59
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Pulsed laser deposition of a ZnO:Eu3+ thin film: study of the luminescence and surface state under electron beam irradiation
摘要： A highly c-axis orientated Eu3+ doped ZnO (ZnO:Eu3+) thin film was successfully deposited by pulsed laser deposition in an oxygen working atmosphere. The structure, morphology, chemical analysis and luminescence properties of the sample were investigated. The effect of electron beam irradiation on the surface state, chemical and luminescence properties of the sample were studied. Successful incorporation of Eu3+ ions in the ZnO matrix was confirmed by X-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) analysis. XPS measurements revealed traces of the divalent (Eu2+) on the film surface while the trivalent (Eu3+) oxidation state in the bulk of the film. XPS depth profile confirmed that the film contained excess oxygen throughout the film. The film exhibited exciton and defect emission of ZnO as well as 4f – 4f characteristic emission of Eu3+ ions superimposed on the defect emission when excited at 325 nm using a He-Cd laser. Whereas only 4f – 4f characteristic emission of Eu3+ ions was recorded when the film was excited at 464 nm and also when excited with the electron beam. XPS high resolution spectra of the O 1s peak confirmed the creation of new defects during electron beam irradiation. In general, ZnO:Eu3+ films show potential for applications as a source of red light in optoelectronic devices.
关键词： Degradation,PLD,ZnO thin film,Eu3+ ions,Cathodoluminescence,Red emission,Electron beam irradiation
更新于2025-09-19 17:13:59
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Facile Preparation of MnO <sub/>2</sub> Quantum Dots with Enhanced Fluorescence via the Micro-environment Engineering with the Assistance of Some Reductive Biomolecules
摘要： MnO2 nanomaterials have been aroused wide attention because of their nano-enzyme activity, redox property, good biocompatibility and therapy-related activities. However, not any report about self-luminescent MnO2 materials are concerned to date, which greatly hampered their further development in various fields. In this paper, luminescent MnO2 quantum dots (MnO2 QDs) has been firstly prepared via a facile one-step ultrasonic method. With the assistant of bovine serum albumin (BSA) or cysteine (Cys), the synthesized MnO2 QDs (BSA-MnO2 QDs or Cys-MnO2 QDs) display strongly enhanced fluorescence (FL). The prepared BSA-MnO2 QDs with the particles size of about 1-2 nm show the maximum excitation and emission peaks at 320 and 410 nm with excellent salt stability, anti-photo bleaching ability and time stability. It is confirmed that BSA play the dual function as the exfoliating agent to promote the exfoliation of bulk MnO2 nanosheets and as the capping agent to provide a friendly micro-environment for MnO2 QDs. Ag ions can destroy the micro-environment of BSA-MnO2 QDs owing to the in-situ formation of Ag nanoparticles (Ag NPs) mediated by the BSA on the surface of the QDs. Then these Ag NPs can quench the FL intensity of the QDs by fluorescence resonance energy transfer. However, the FL strength of BSA-MnO2 QDs is recovered after adding H2O2 and NaHS since they may react with Ag NPs to produce Ag+ and Ag2S, which further confirmed the role of BSA. This work not only opens a facile and universal avenue to synthesize luminescent MnO2 QDs with enhanced FL, but provide a possible sensing platform through tuning the micro-environment of MnO2 QDs. The MnO2 QDs with outstanding performance may show great potential as promising fluorescent probes in the fields of biological imaging, optical sensing, drug delivery and therapy.
关键词： micro-environment engineering,reductive biomolecules,MnO2 QDs,enhanced fluorescence,Ag ions
更新于2025-09-19 17:13:59