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Three‐stage kinetics of laser‐induced LiFePO <sub/>4</sub> decomposition
摘要： This paper reports about new insight into a problem of a laser–matter interaction during Raman probing of lithium iron phosphate (LiFePO4), discusses phase transformation kinetics in powder samples, and provides methodological recommendations. LiFePO4 is the second most popular positive electrode material in the global lithium battery industry, but the use of Raman spectroscopy for its structural characterization is hampered by the laser‐induced degradation. The statistical/big‐data approach to Raman spectra measurements is utilized to revise the problem and suggest a simple model of laser‐induced phase transformations in powder LiFePO4. The results are proposed to be used for better understanding of the physics and chemistry of other processes taking place in electrochemical cells, namely, lithiation/delithiation and thermal stability/safety studies. Simple recommendations for nondestructive LiFePO4 characterization by Raman spectroscopy are formulated.
关键词： lithium iron phosphate,nondamaging characterization,statistical Raman spectroscopy,lithium batteries,statistical Raman microscopy
更新于2025-09-12 10:27:22
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Carbon quantum dots (CQDs) modified ZnO/CdS nanoparticles based fluorescence sensor for highly selective and sensitive detection of Fe(III)
摘要： A simple and fast spectrofluorimetric method coupled with carbon quantum dots (CQDs) modified ZnO/CdS nanoparticles was developed for the detection of Ferric iron (Fe(III)). The fluorescence of CQDs/ZnO/CdS NPs was effectively quenched by Fe(III) due to the strong interaction between the CQDs/ZnO/CdS NPs and Fe(III). In addition, the detection limit of Fe(III) was about 1.72 × 10^-7 M. The effect of foreign ions on the fluorescence intensity of CQDs/ZnO/CdS NPs showed that the interference response in detecting of Fe(III) ions was low. Moreover, the quenching of Fe(III) and CQDs/ZnO/CdS NPs was discussed to be a static quenching procedure, which was proved by quenching constant KSV and fluorescence lifetime τ. The study of thermodynamics showed that the values of entropy change (?S) and enthalpy change (?H) were both positive, and the values of free energy (?G) was negative, which implied that the weak interaction of the molecular between CQDs/ZnO/CdS NPs and Fe(III) was hydrophobic force, and the quenching process was endothermic and spontaneous.
关键词： Static quenching,Ferric iron,CQDs/ZnO/CdS NPs,Fluorescence sensor
更新于2025-09-12 10:27:22
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Cadmium sulfide quantum dots impact Arabidopsis thaliana physiology and morphology
摘要： The differential mechanisms of CdS QDs (Quantum Dots) and Cd ion toxicity to Arabidopsis thaliana (L.) Heynh were investigated. Plants were exposed to 40 and 60 mg L-1 for CdS QDs and 76.9 and 115.2 mg L-1 CdSO4·7H2O and toxicity was evaluated at 5, 20, 35 (T5, T20, T35) days after exposure. Oxidative stress upon exposure was evaluated by biochemical essays targeting non-enzymatic oxidative stress physiological parameters, including respiration efficiency, total chlorophylls, carotenoids, ABTS and DPPH radicals reduction, total phenolics, GSH redox state, lipid peroxidation. Total Cd in plants was measured with AAS. Root and leaf morphology and element content were assessed in vivo utilizing low-vacuum Environmental Scanning Electron Microscopy (ESEM) with X-ray microanalysis (EDX). This integrated approach allowed identification of unique nanoscale CdS QDs toxicity to the plants that was distinct from CdSO4 exposure. The analyses highlighted that CdS QDs and Cd ions effects are modulated by the developmental stage of the plant, starting from T20 till T35 the plant development was modulated by the treatments, in particular CdS QDs induced early flowering. Both treatments induced Fe accumulation in roots, but at different intensities, while CdS QDs was associated with Mn increase into plant leaf. CdSO4 elicited higher levels of oxidative stress compared with QDs, especially the former treatment caused more intense respiration damages and reduction in chlorophyll and carotenoids than the latter. The two types of treatments impact differently on root and leaf morphology.
关键词： oxidative stress,morphology,Arabidopsis thaliana,Iron,ESEM/EDX,CdS QDs
更新于2025-09-12 10:27:22
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There Is a Future for N-Heterocyclic Carbene Iron(II) Dyes in Dye-Sensitized Solar Cells: Improving Performance through Changes in the Electrolyte
摘要： By systematic tuning of the components of the electrolyte, the performances of dye-sensitized solar cells (DSCs) with an N-heterocyclic carbene iron(II) dye have been significantly improved. The beneficial effects of an increased Li+ ion concentration in the electrolyte lead to photoconversion efficiencies (PCEs) up to 0.66% for fully masked cells (representing 11.8% relative to 100% set for N719) and an external quantum efficiency maximum (EQEmax) up to approximately 25% due to an increased short-circuit current density (JSC). A study of the effects of varying the length of the alkyl chain in 1-alkyl-3-methylimidazolium iodide ionic liquids (ILs) shows that a longer chain results in an increase in JSC with an overall efficiency up to 0.61% (10.9% relative to N719 set at 100%) on going from n-methyl to n-butyl chain, although an n-hexyl chain leads to no further gain in PCE. The results of electrochemical impedance spectroscopy (EIS) support the trends in JSC and open-circuit voltage (VOC) parameters. A change in the counterion from I? to [BF4]? for 1-propyl-3-methylimidazolium iodide ionic liquid leads to DSCs with a remarkably high JSC value for an N-heterocyclic carbene iron(II) dye of 4.90 mA cm?2, but a low VOC of 244 mV. Our investigations have shown that an increased concentration of Li+ in combination with an optimized alkyl chain length in the 1-alkyl-3-methylimidazolium iodide IL in the electrolyte leads to iron(II)-sensitized DSC performances comparable with those of containing some copper(I)-based dyes.
关键词： N-heterocyclic carbene,iron,dye-sensitized solar cell,ionic liquid,lithium ion,electrolyte
更新于2025-09-12 10:27:22
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Simultaneous positive and negative optical patterning with dye-sensitized CdSe quantum dots
摘要： CdSe quantum dots are functionalized with the organic dye iron β-tetraaminophthalocyanine to reward a solution-processable hybrid material with two individually addressable optical resonances. We exploit this dual functionality during optical write/optical read patterning experiments and show that it is possible to simultaneously write complex optical patterns with positive and negative fluorescence contrast. This is enabled by a fluorescence enhancement under near-resonant excitation of the quantum dots in combination with a fluorescence bleaching during excitation of the singlet transition of the phthalocyanine. The presence of the organic dye not only enables negative optical patterning but also enhances the contrast during positive patterning. Furthermore, the patterning result is strongly dependent on the excitation wavelength during readout. Our results highlight the new possibilities that arise from combining inorganic quantum dots and organic π-systems into hybrid nanocomposites.
关键词： fluorescence contrast,optical patterning,iron β-tetraaminophthalocyanine,CdSe quantum dots,hybrid nanocomposites
更新于2025-09-12 10:27:22
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Use of Lasers for Iron-Induced Accidental Tattoos
摘要： BACKGROUND Awareness of accidental tattoos after iron injections with paravenous leakage is low. No larger patient cohorts have been analyzed. The lesions are a burden to the patients. The only known treatment is laser therapy. OBJECTIVE To characterize the clinical appearance and development of iron-induced tattoos and to demonstrate safe and efficient removal with quality-switched (QS) and picosecond lasers. MATERIALS AND METHODS The authors conducted a retrospective systematic analysis on patients who presented at the Dermatology Department of the University Hospital of Zurich between Year 2008 and 2017 with accidental hyperpigmentations after iron injections. From 29 collected patients, 13 received laser treatment and were analyzed with reference to the lasers used, including wavelength, fluence, spot size, intervals, number of sessions, and overall success. The authors defined the latter as a complete removal or as patients’ satisfaction. RESULTS The authors treated 13 patients and completed the treatment in 8 patients, with an average of 5.6 sessions. No complications occurred. CONCLUSION Spontaneous regression of iron-induced tattoos is possible within 1 to 2 years, but not guaranteed. Removal with QS ruby, Nd:YAG, and picosecond lasers can be achieved within a mean number of 5.6 sessions. Assuring a valid indication before intravenous iron administration is important.
关键词： picosecond lasers,iron-induced tattoos,hyperpigmentation,quality-switched lasers,laser therapy
更新于2025-09-12 10:27:22
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Physical properties of cerium doped-yttrium iron garnet ultrathin films for photovoltaic application
摘要： In this study, cerium incorporated yttrium iron garnet ultrathin films (CexY3-xFe5O12) (where x = 0, 0.1, 0.3, and 0.5) were prepared by the sol-gel method, spin coating technique, and heat treatment on quartz substrates. The effect of Ce on structural properties, morphology of thin films surface, and optical properties was explored by X-ray diffraction (XRD), field emission microscopy (FESEM), and atomic force microscopy (AFM). According to the XRD results, the films were crystalline with the cubic phase, while the FESEM indicated the YIG nanoparticles with approximately spherical shapes. The growth process of crystallite in YIG nanoparticles was investigated by X-ray peak broadening. The Williamson-Hall (W–H) analysis was utilized to maintain the contributions of crystallite size on the peak broadening of Ce:YIG nanoparticles. The structural features of thin films such as strain and stress for all of the peaks of XRD were accurately determined from the uniform deformation model (UDM) according to the YIG cubic phase. According to the AFM pictures, it seemed that thin films had a continuous and smooth surface. The absorption and transmission were measured in the visible and infrared region from 400 to 1200 nm.
关键词： Structural features,Cerium yttrium iron garnet thin films,Photovoltaic application,Optical properties,Sol-gel
更新于2025-09-12 10:27:22
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Fabrication of high photosensitivity nanostructured n-Fe<sub>2</sub>O<sub>3</sub>/p-Si heterojunction photodetector by rapid thermal oxidation of chemically sprayed FeS<sub>2</sub> film
摘要： In this study, we have reported a novel route for the preparation of α-Fe2O3 by rapid thermal oxidation RTO of chemical sprayed FeS2 film at 550°C/20s condition under oxygen ambient. FeS2 to Fe2O3 film after RTO process. Raman shift data of Fe2O3 shows the presence of five Raman active vibration modes indexed to A1g and E1g modes. The dark and illuminated current-voltage properties of n-Fe2O3/p-Si heterojunctions have been investigated in the absence of the buffer layer and the ideality factor of n-Fe2O3/p-Si was 2.7.The responsivity of Fe2O3/Si photodetector was 0.51A/W at 500nm and 0.37A/W at 850nm. The specific detectivity of the photodetector was measured and it was around 60ns.The energy band line-up of n-Fe2O3/p-Si heterojunction was demonstrated under illumination condition.
关键词： Rapid thermal oxidation,Heterojunction,Energy band –line-up,Iron oxide,Iron sulfide
更新于2025-09-11 14:15:04
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Green and simple preparation of carbon-coated iron pyrite thin films for solar cells application
摘要： Carbon-coated iron pyrite (FeS2@C) was prepared by a green and simple method. The utilization of an amorphous carbon-shell layer formed from a glucose source coated on the surface of core-pyrite nanoparticles. The FeS2@C thin film was formed by coating synthesized iron pyrite nanoparticles with a carbon layer and depositing the carbon-coated iron pyrite on a fluorine-doped tin oxide (FTO) substrate by spin-coating. The morphological, structural, and chemical composition properties of FeS2@C film was measured and characterized. Devices with the structure of FTO/TiO2/redox electrolyte/counter electrodes (FeS2@C, pristine FeS2, and Pt)/FTO were fabricated. The power conversion efficiency (PCE) of the FeS2@C-device (PCE ~ 6.94%), the pristine FeS2-device (PCE ~ 5.69%), the Pt-device (PCE ~ 6.48%). The improving of the device performance indicated that the FeS2@C thin film can be a good counter electrode (CE) for the performance of dye-sensitized solar cells (DSSCs).
关键词： Dye-sensitized solar cells,Carbon-coated iron pyrite,FeS2@C,Counter electrode,Power conversion efficiency
更新于2025-09-11 14:15:04
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Application of Laser-Induced Breakdown Spectroscopy to Real-Time Elemental Monitoring of Iron and Steel Making Processes
摘要： Steel industry is the irreplaceable foundation in heavy industries, which have been developed and improved. The advanced monitoring methods including detection and control technology contribute to its development of iron and steel manufacturing processes. With the development of the measurement techniques, laser-induced breakdown spectroscopy (LIBS) has been developed and applied for many industrial fields of elemental monitoring due to the non-contact, fast response, high sensitivity, real-time and multi-dimensional features. The elemental measurement methods in steel industry were summarized and compared in this paper. LIBS measurements of raw material, smelting processes, products, slag, etc. have been reviewed in detail. Challenges for the future of LIBS application in iron and steel making processes have also been discussed. LIBS has a high potential to improve the detection ability of elemental analyses and to promote the on-line monitoring characteristics in iron and steel making plants.
关键词： real-time,elemental monitoring,iron and steel making processes,laser-induced breakdown spectroscopy
更新于2025-09-11 14:15:04