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Eu-doped layered yttrium hydroxides sensitized by series of benzenedicarboxylate and sulphobenzoate anions
摘要： A number of Eu-doped layered yttrium hydroxides intercalated with various benzenedicarboxylate (phthalate, isophthalate and terephthalate) and sulphobenzoate (2-, 3- and 4-sulphobenzoate) anions was obtained using hydrothermal microwave (HTMW) treatment. For the first time, phthalate, isophthalate and sulphobenzoate anions were intercalated into layered rare-earth hydroxides (LRHs). Two approaches to the synthesis of intercalated layered yttrium hydroxides were used: ion exchange reactions and homogeneous hydrolysis of rare-earth cations in the presence of the intercalated anion. Ion-exchange reactions between layered rare-earth hydroxides and a series of benzenedicarboxylic and sulphobenzoic acid salts were performed under conditions of HTMW treatment, which significantly increased the rate of intercalation. The structure of the first representative of layered rare-earth hydroxides intercalated with sulphobenzoate-type anions, namely layered yttrium hydroxide intercalated with 4-sulphobenzoate of composition Y3(OH)7(C7H4O5S)·H2O, was solved. Intercalation of benzenedicarboxylate and sulphobenzoate anions into Eu-doped layered yttrium hydroxides led to a substantial sensitization of Eu3+ luminescence. The local symmetry of Eu3+ was greatly decreased by intercalation of benzenedicarboxylate and sulphobenzoate anions.
关键词： Layered rare-earth hydroxides,anion exchange,LRH,hydrothermal microwave treatment,luminescence,hybrid materials
更新于2025-11-21 11:20:42
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In situ anion exchange strategy to construct flower-like BiOCl/BiOCOOH p-n heterojunctions for efficiently photocatalytic removal of aqueous toxic pollutants under solar irradiation
摘要： The poor charge separation of single-component semiconductor photocatalysts greatly restrains their practical application. Herein, we report an in situ anion-exchange strategy to controllably fabricate sunlight-driven p-n heterostructure photocatalyst BiOCl/BiOCOOH. In this synthetic process, the BiOCOOH microspheres not only act as the support to form heterostructures but also as Bi3+ supplier to generate BiOCl. Such an in situ anion-exchange route thus brought about the homogeneous distribution of BiOCl on the surface of BiOCOOH with tight interfacial contact. Under simulated solar illumination, the obtained BiOCl/BiOCOOH catalysts with p-n heterostructures show exceedingly superior photocatalytic activity against toxic pollutant (MO dye and TC antibiotic) to BiOCOOH and BiOCl. The optimal BiOCl/BiOCOOH, S3 sample has the highest photocatalytic activity with MO degradation rate constant of 0.0599 min?1, 2.9 or 9.7 folds higher than that of BiOCOOH or BiOCl. The alleviated charge separation and transfer as well as the flower-like structure mainly account for the enhanced performance. Radical scavenging experiments indicate that holes, ?OH and ?O2? collaboratively contribute to the degradation of pollutants. This work provides a novel sunlight-driven p-n heterojunction photocatalyst of BiOCl/BiOCOOH for wastewater treatment.
关键词： Anion exchange,Sunlight,BiOCl/BiOCOOH,Photocatalysis,p-n heterojunction
更新于2025-09-23 15:23:52
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Formation of zirconia precursor nanoplates mediated by ionic liquid and transformation to monoclinic ZrO <sub/>2</sub> nanostructures
摘要： The [Zr(OH)5]– imidazolium complex was used to synthesize a zirconia precursor with plate-like nanostructure hydrolyzed under strong acid conditions, which was characterized by means of powder X-ray diffraction, thermogravimetric-differential scanning calorimetry, Fourier transform infrared spectroscopy, Raman spectroscopy, elemental analysis, inductively coupled plasma and electronic differential system. The zirconia precursor can be transformed to monoclinic ZrO2 by annealing at a temperature above 400 °C. With the increasing of the curing temperature, it tended to give rise to porous ZrO2 nanostructures.
关键词： Zirconia precursor,Zirconium oxide,Anion exchange reaction,Nanoplate,Ionic liquid
更新于2025-09-23 15:22:29
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Bright Blue Light Emission of Ni2+ ions doped CsPbClxBr3-x Perovskite Quantum Dots Enabling Efficient Light-Emitting Devices
摘要： In recent years, significant advances have been achieved in the red and green perovskite quantum dots（PQDs）based light-emitting diodes (LEDs). However, the performances of the blue perovskite LEDs are still seriously lagging behind that of the green and red counterparts. Herein, we successfully developed Ni2+ ions doped CsPbClxBr3-x PQDs through the room-temperature supersaturated recrystallization synthetic approach. We simultaneously realized the doping of various concentrations of Ni2+ cations, and modulated the Cl/Br element ratios through introducing different amount of NiCl2 solution in the reaction medium. By the synthetic method, not only the emission wavelength from 508 to 432 nm of Ni2+ ions doped CsPbClxBr3-x QDs was facially adjusted, but also the photoluminescence quantum yield (PLQY) of PQDs was greatly improved due to efficiently removing the defects of the PQDs. Thus, the blue emission at 470 nm with PLQY of 89% was achieved in 2.5% Ni2+ ions doped CsPbCl0.99Br2.01 QDs, which increased nearly three times over that of undoped CsPbClBr2 QDs, and was the highest for the CsPbX3 PQDs with blue emission that fulfilling the NTSC standards. Benefiting from the high luminous Ni2+ ions doped PQDs, the blue emitting LED at 470 nm was obtained, exhibiting an external quantum efficiency (EQE) of 2.4% and a maximum luminance of 612 cd/m2, which surpassed the best performance reported previously for the corresponding blue-emitting PQDs based LED.
关键词： perovskite QD-LEDs,Ni2+ ion doping,blue emission,anion exchange,perovskite quantum dots
更新于2025-09-23 15:21:01
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Laser-Assisted Fabrication for Metal Halide Perovskite-2D Nanoconjugates: Control on the Nanocrystal Density and Morphology
摘要： We report on a facile and rapid photo-induced process to conjugate graphene-based materials with metal-halide perovskite nanocrystals. We show that a small number of laser pulses is sufficient to decorate the 2-dimensional (2D) flakes with metal-halide nanocrystals without affecting their primary morphology. At the same time, the density of anchored nanocrystals could be finely tuned by the number of irradiation pulses. This facile and rapid room temperature method provides unique opportunities for the design and development of perovskite-2D nanoconjugates, exhibiting synergetic functionality by combining nanocrystals of different morphologies and chemical phases with various 2D materials.
关键词： graphene oxide,2D materials,photo-induced processes,laser-induced synthesis,nanoparticles,anion exchange,synergistic effects
更新于2025-09-23 15:19:57
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Anion Exchange and the Quantum-Cutting Energy Threshold in Ytterbium-Doped CsPb(Cl1-xBrx)3 Perovskite Nanocrystals
摘要： Colloidal halide perovskite nanocrystals of CsPbCl3 doped with Yb3+ have demonstrated remarkably high sensitized photoluminescence quantum yields (PLQYs), approaching 200%, attributed to a picosecond quantum-cutting process in which one photon absorbed by the nanocrystal generates two photons emitted by the Yb3+ dopants. This quantum-cutting process is thought to involve a charge-neutral defect cluster within the nanocrystal's internal volume. Here, we demonstrate that Yb3+-doped CsPbCl3 nanocrystals can be converted post-synthetically to Yb3+-doped CsPb(Cl1-xBrx)3 nanocrystals without compromising the desired high PLQYs. Nanocrystal energy gaps can be tuned continuously from Eg ~ 3.06 eV (405 nm) in CsPbCl3 down to Eg ~ 2.53 eV (~490 nm) in CsPb(Cl0.25Br0.75)3 while retaining a constant PLQY above 100%. Reducing Eg further causes a rapid drop in PLQY, interpreted as reflecting an energy threshold for quantum cutting at approximately twice the energy of the Yb3+ 2F7/2 → 2F5/2 absorption threshold. These data demonstrate that very high quantum-cutting energy efficiencies can be achieved in Yb3+-doped CsPb(Cl1-xBrx)3 nanocrystals, offering the possibility to circumvent thermalization losses in conventional solar technologies. The presence of water during anion exchange is found to have a deleterious effect on the Yb3+ PLQYs but does not affect the nanocrystal shapes, morphologies, or even reduce the excitonic PLQYs of analogous undoped CsPb(Cl1-xBrx)3 nanocrystals. These results provide valuable information relevant to development and application of these unique materials for spectral-shifting solar energy conversion technologies.
关键词： ytterbium doping,quantum cutting,anion exchange,Perovskite nanocrystals
更新于2025-09-19 17:15:36
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Fabrication and optimization of nanocube mixed halide perovskite films for solar cell application
摘要： In this article, we report the tailoring of nanostructured mixed halide perovskite MAPb(I1-xBrx)3 films with tunable band gap fabricated by anion exchange reaction. In this process, we used PbBr2 and methyl ammonium iodide (MAI) in order to fabricate mixed halide perovskite films. We have observed an uncommon shape transformation from nanocube-hollow tetraoids-nanocubes/plate. The underlying mechanism of shape transformation was discussed based on experimental results. The driving force for such shape transformation is combined effect of anion exchange reaction between I? and Br? at the solid/liquid interface of PbBr2 and MAI, and mechanical driving force exerted by the spin coating process. The shape transformation is highly reproducible, verified by two step process, dipping as well as spinning process. The best performing device using the nanostructured perovskite films in a device architecture FTO/TiO2/MAPb(I1-xBrx)3/Spiri-OMeTAD/Au shows a current density (Jsc,) of 23.58 mA/cm2, open circuit voltage (Voc) of 0.891 V and fill factor (FF) of 0.608, with a power conversion efficiency (η) of 12.79% in forward sweep. In reverse sweep, the device shows the Jsc (mA/cm2), Voc (V), FF, and η (%) are 23.852, 0.891, 0.716 and 15.237, respectively.
关键词： Nanostructured perovskite films,Anion exchange reaction,Shape transformation,Mixed halide perovskite films,Perovskite solar cell
更新于2025-09-19 17:13:59
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Pink all-inorganic halide perovskite nanocrystals with adjustable characteristics: Fully reversible cation exchange, improving the stability of dopant emission and light-emitting diode application
摘要： In this work, we proposed a straightforward and effective strategy for preparing pink all-inorganic halide perovskite nanocrystal (NC) phosphors for light-emitting diode (LED) application. The pink perovskite NCs with varying Mn contents could be easily and steadily obtained via postsynthetic ion exchange at room temperature. The dependence of the size and optical properties of pink NCs on dopant content was systematically investigated. The reversible anion exchange processes of pink perovskite NCs were conducted with halide salts containing or excluding Pb. The contrasting results suggested that the irreversibility of Mn-emission was mainly affected by the fully reversible cation exchange between Pb2+ and Mn2+. The pink NCs with better stability of dopant emission and high monodispersity were successfully developed by compounding with silica. A pink LED was further made by using the pink NCs/silica composites as pink phosphors on a 395 nm InGaN LED chip. This work provides a feasible strategy for the fabrication of pink LEDs, which may have great application prospects in the field of special lighting, like neon lights and plant growth lights.
关键词： light-emitting diodes,anion exchange,perovskite nanocrystals,stability,cation exchange
更新于2025-09-12 10:27:22
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An anion exchange membrane electrode assembled photoelectrochemical cell with a visible light responsive photoanode for simultaneously treating wastewater and generating electricity
摘要： In this work, an anion exchange membrane electrode assembled photoelectrochemical cell is designed for simultaneously degrading organics and generating electricity. The proposed photoelectrochemical cell is formed by assembling a visible light responsive photoanode and an air-breathing cathode with an anion exchange membrane. Benefited from the intrinsic property of the anion exchange membrane, the hydroxyl transport can be enhanced and the organics crossover can be reduced to improve the performance of the proposed photoelectrochemical cell. Experimental results show that increasing the electrolyte concentration and light intensity yields higher performance because of the more efficient capture and generation of photo-excited holes. Besides, the cell performance can also be enhanced with increasing ethanol concentration in the testing range, demonstrating the lowered ethanol crossover through the anion exchange membrane and mixed potential at the cathode. The obtained results are useful for not only the optimization of the photoelectrochemical cell design but also the promotion of its practical application.
关键词： Membrane electrode assembly,Air-breathing cathode,Photoelectrochemical cell,Visible light response,Anion exchange membrane
更新于2025-09-12 10:27:22
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Anion exchange polymeric sorbent coupled to high‐performance liquid chromatography with <scp>UV</scp> diode array detection for the determination of ten <i>N</i> ‐nitrosamines in meat products: a validated approach
摘要： Among mechanisms and molecules presumably involved in the carcinogenicity induced by meat consumption, the N-nitrosamines (N-NAs) are a class of compounds characteristic of processed meats. In this work, an analytical method for the determination of 10 N-Nitrosamines (N-Nitrosomorpholine, N-Nitriosomethyethylamine, N-Nitrosopyrrolidine, N-Nitrosodiethylamine, N-Nitrosopiperidine, N-Nitrosodipropylamine, N-Nitrosomethylaniline, N-Nitrosodibutylamine, N-Nitrosodiphenylamine, N-Nitrosodibenzylamine) in fresh meats and meat products was developed, optimized and validated. The method is based on optimized sample purification by solid phase extraction (anion exchange polymeric sorbent) and separation/detection by high performance liquid chromatography coupled to UV diode array detection. The validation procedure allowed to ascertaining good analytical performances in terms of sensitivity, selectivity towards interfering compounds, accuracy and robustness. The values obtained for precision (range: 4.3% - 14.4%) and recovery percentages (range: 80.8% - 95.1%) were compared to reference values indicated in the Decision No. 657/2002/EC, resulting as compliant. The measurement uncertainty (lower than 14.6%) was satisfactory for each N-NA as well.
关键词： meat,food safety,solid phase extraction,validation,diode array detection,Nitrosamines,processed meats,HPLC,carcinogenic compounds,anion exchange sorbent
更新于2025-09-11 14:15:04