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Growth and Characterization of Cu2Zn1a??xFexSnS4 Thin Films for Photovoltaic Applications
摘要： Photovoltaics is a promising technology to produce sustainable energy, thanks to the high amount of energy emitted by the sun. One way of having solar cells with low production costs is to apply thin-film technology and with earth-abundant raw materials. A keen interest is arising in kesterite compounds, which are chalcogenides composed of abundant and non-toxic elements. They have already achieved excellent performance at the laboratory level. Here, we report the synthesis and characterization of mixed chalcogenides based on copper, zinc, iron, and tin. Solutions have been studied with different zinc and iron ratios. The distortion of the elementary cell of kesterite increases with the addition of iron until a phase transition to stannite occurs. The process of synthesis and deposition proposed herein is cheap and straightforward, based on the sol-gel technique. These thin films are particularly attractive for use in cheap and easily processable solar cells. The synthesized layers have been characterized by X-ray diffraction, UV-Vis absorption, and Raman, X-ray photoelectron, and energy-dispersive X-ray spectroscopy measurements.
关键词： chalcogenide solar cells,iron chalcogenide,sustainable energy,kesterite,stannite
更新于2025-09-23 15:19:57
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Remarkable Oxygen-Evolution Activity of Ca2-xSrxFe2O6-δ
摘要： The unprecedented catalytic activity of an iron-based oxygen-deficient perovskite for oxygen-evolution reaction (OER) is reported, given the need for catalysts based on earth-abundant elements. In addition, systematic trends in oxygen-evolution activity as a function of composition, defect-order and electrical conductivity have been demonstrated, leading to a methodical increase in OER catalytic activity: Ca2Fe2O6-δ < CaSrFe2O6-δ < Sr2Fe2O6-δ. The latter material, which has the highest electrical conductivity and a unique type of defect-order, exhibits the best OER activity. In conventional experiments using glassy carbon electrode, this compound shows superior OER activity compared to the current state of the art catalysts, Ba0.5Sr0.5Co0.8Fe0.2O3?δ and RuO2. It also offers an additional advantage, namely high intrinsic electrical conductivity, which allows Sr2Fe2O6-δ to act as a catalyst without the need for glassy carbon electrode or carbon powder, that are frequently used for enhancing the charge transport in OER catalysts. Indeed, pure disks of this material exhibit an outstanding activity for OER, without any additives or need for electrode preparation.
关键词： oxygen-evolution reaction,perovskite phases,iron,defect-order,electrical conductivity
更新于2025-09-23 15:19:57
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Fe <sup>3+</sup> -SELECTIVE ENHANCED FLUORESCENCE PROBE BASED ON A RHODAMINE DERIVATIVE
摘要： A novel Fe3+-selective and turn-on fluorescent probe 1 incorporating a rhodamine fluorophore and quinoline subunit was synthesized. Probe 1 displayed high selectivity for Fe3+ in CH3CN–H2O (95:5 v/v) in the presence of other relevant metal cations. Interaction with Fe3+ in 1:1 stoichiometry could trigger a significant fluorescence enhancement due to the formation of the ring-open form. The fluorescent response images were investigated by a novel Euclidean distance method based on red, green, and blue values. A linear relationship was observed between fluorescence intensity changes and Fe3+ concentrations from 7.3 × 10?7 to 3.6 × 10?5 mol L?1.
关键词： fluorescence,Euclidean distance,iron probe
更新于2025-09-23 15:19:57
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The Catalytic Activity Enhancement of Commercial TiO2 and Nb2O5 Catalysts by Iron for Elemental Sulfur Production from H2S
摘要： Commercial TiO2 and Nb2O5 catalysts were used to determine catalytic activities for selective oxidation of H2S to elemental sulfur. Fe@TiO2 and Fe@Nb2O5 catalysts (containing 10% iron by weight) were also prepared by wet impregnation method to enhance the catalytic activity. TiO2 anatase phase and Nb2O5 were mainly observed in the crystalline structure of TiO2 and Nb2O5 based catalysts, respectively. Catalytic activity tests were performed in a fixed-bed flow reactor at 250 °C using stoichiometric feed ratio. 30% and 28% H2S conversions were obtained with commercial TiO2 and Nb2O5 catalysts. Complete conversion of H2S was reached with Fe@TiO2 and Fe@Nb2O5 catalysts at the same reaction conditions for 400 min. of reaction time. 100% of H2S conversion was obtained with iron-containing catalysts in the reaction tests carried out at 200 °C and 300 °C of reaction temperatures. Fe@TiO2 and Fe@Nb2O5 catalysts showed high sulfur selectivity (≥ 95%) under all reaction conditions. Iron addition enhanced the Lewis acidity and redox property of the commercial catalysts and this may be the reason for increase in catalytic activity.
关键词： H2S,Elemental sulfur,Commercial catalyst,Iron
更新于2025-09-23 15:19:57
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Fluorescence resonance energy transfer links membrane ferroportin, hephaestin but not ferroportin, amyloid precursor protein complex with iron efflux
摘要： Iron efflux from mammalian cells is supported by the synergistic actions of the ferrous iron efflux transporter, ferroportin (Fpn) and a multicopper ferroxidase, that is, hephaestin (Heph), ceruloplasmin (Cp) or both. The two proteins stabilize Fpn in the plasma membrane and catalyze extracellular Fe3+ release. The membrane stabilization of Fpn is also stimulated by its interaction with a 22-amino acid synthetic peptide based on a short sequence in the extracellular E2 domain of the amyloid precursor protein (APP). However, whether APP family members interact with Fpn in vivo is unclear. Here, using cyan fluorescent protein (CFP)-tagged Fpn in conjunction with yellow fluorescent protein (YFP)-fusions of Heph and the APP family members APP, APLP1, and APLP2 in HEK293T cells we used fluorescence and surface biotinylation to quantify Fpn membrane occupancy and also measured 59Fe efflux. We demonstrate that Fpn and Heph co-localize, and FRET analysis indicated that the two proteins form an iron-efflux complex. In contrast, none of the full-length, cellular APP proteins exhibited Fpn co-localization or FRET. Moreover, iron supplementation increased surface expression of the iron-efflux complex, and copper depletion knocked down Heph activity and decreased Fpn membrane localization. Whereas cellular APP species had no effects on Fpn and Heph localization, addition of soluble E2 elements derived from APP and APLP2, but not APLP1, increased Fpn membrane occupancy. We conclude that a ferroportin-targeting sequence, K/REWEE, present in APP and APLP2, but not APLP1, helps modulate Fpn-dependent iron efflux in the presence of an active multicopper ferroxidase.
关键词： cell surface protein,hephaestin,iron metabolism,membrane transport,metal transport,Ferroportin,multicopper ferroxidase,APP-like proteins,iron efflux,amyloid precursor protein
更新于2025-09-19 17:15:36
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Imaging Interstitial Iron Concentrations in Gallium-Doped Silicon Wafers
摘要： In this work, the established method of iron imaging is transferred from B-doped silicon to Ga-doped material. For this purpose, the pairing and splitting conditions are investigated and a preparation procedure suggested that ensures a sufficient fraction of iron–gallium pairing and splitting, respectively. Furthermore the defect parameters available in literature are compared and evaluated for a suitable description of the injection dependent carrier lifetime measurements. A parameter set that enables a coherent and adequate iron evaluation is suggested. Thus, a robust method for spatially resolved determination of the interstitial iron concentration in Ga-doped silicon wafers is presented.
关键词： multicrystalline silicon,defect parameters,photoluminescence,iron imaging,Ga-doped silicon
更新于2025-09-19 17:15:36
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Understanding the Citric Acid-Urea Co-Directed Microwave Assisted Synthesis and Ferric Ion Modulation of Fluorescent Nitrogen Doped Carbon Dots: A Turn On Assay for Ascorbic Acid
摘要： Herein, nitrogen doped carbon dots (NCDs) were synthesised from citric acid and urea via a previously reported microwave assisted route. The NCDs shows emission maximum at 500 nm on excitation at 400 nm. The fluorescence of NCDs decreases slightly with increase in basicity of solution up to pH 7.5 and then increases again after pH 8.5, along with a blue-shift in tested alkaline pH. This pH dependent blue-shift indicates the presence of both carboxyl?carboxylate and phenol?phenolate prototropic equilibrium in NCDs. Due to the special interaction of these phenolates and carboxylates on NCDs surface with di- or tri- valent heavy transition metal ions; it is demonstrated that ferric ion (Fe3 + ion) can quench the fluorescence of NCDs. This Fe3 + induced static quenching of NCDs is a collaborative effect of inner filter effect, aggregation and ferromagnetism. However, Ascorbic acid (AA) can recover the fluorescence of Fe3 + quenched NCD with detection limit as low as 96 μM. This detection strategy has good selectivity towards AA over other antioxidants, saccharides, proteins and neurotransmitters. Furthermore, (spiked) human serum and (spiked) human urine were analysed and found good recovery percentage.
关键词： Fluorescence,Ascorbic Acid,Biosensor,Inner Filter Effect,Iron(III),Carbon Dots
更新于2025-09-19 17:15:36
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Preparation of pyrido[1,2-c][1,2,4]triazole-based π-conjugated triazene as a Fe3+ ion fluorescent sensor
摘要： A highly efficient coupling reaction of N-heterocyclic carbene precursors with sulfonyl azides has been developed, affording a variety of pyrido[1,2-c][1,2,4]triazole-based π-conjugated triazenes. The present reaction proceeds under very mild conditions with good functional group tolerance. The resulting triazenes exhibit selective and sensitive fluorescent response toward Fe3+ ion.
关键词： Fluorescence,Triazene,Sulfonyl azide,Iron ion,Sensor
更新于2025-09-19 17:15:36
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A paper-based colorimetric microfluidic sensor fabricated by a novel spray painting prototyping process for iron analysis
摘要： A novel, simple and low-cost spray painting technique has been developed for the fabrication of microfluidic paper-based devices. The devices that we developed utilize aerosol spray paint to build hydrophobic barriers and employ a hole puncher to obtain paper-based patterned layers and paper dots without using any specialized instruments (e.g., without a laser cutter). The entire manufacturing process is extremely simple, inexpensive and rapid, which can be applied broadly. Furthermore, the application of the device to iron detection was demonstrated. A linear relationship between the color value and the iron concentration was observed from 0 to 0.02 g/L. The developed microfluidic paper-based device for iron detection exhibited a low detection limit (0.00090 g/L), good selectivity and acceptable recovery.
关键词： Spray painting,Colorimetry,Microfluidic paper-based device,Iron
更新于2025-09-19 17:15:36
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Structures of silicate glasses with varying sodium and fixed iron contents
摘要： Silicate glasses have been synthesised with a fixed 8 mol% of Fe3O4 and sodium oxide varying from 12 mol% to 20 mol%. The environment of the Fe ion was examined by Extended X-ray Absorption Fine structure and M?ssbauer spectroscopy which have shown tetrahedral coordination of oxygen around Fe regardless of the oxidation state of iron. M?ssbauer data indicate increasing; distortion of these tetrahedral units and Fe3+ to Fe2+ ratios, with increasing sodium concentration. Raman spectroscopic studies have shown the presence of Qn linkages for n = 0 to n = 4. For the sodium silicate glass without iron, the single most common linkage is Q3 (~ 50%) suggesting the role of the alkali to be disruptive to the continuity of the silica random network. For the iron containing glasses, the main linkage is Q2 (~ 65%). However, in the latter glasses the fraction of Q3 linkages although considerably less (~10% to ~20%) than Q2 is shown to increase with alkali content due to the concomitant rise of Fe3+ ions which are known to be network formers.
关键词： Structure,Silicate,Iron,Glass,Sodium
更新于2025-09-19 17:15:36