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Saponification Precipitation Method of CsPbBr3 Nanocrystals with Blue-Green Tunable Emission
摘要： We report on a new synthesis process for halide perovskite nanoplatelets and nanoplates that switches the production process of the cesium precursor from a fatty acid/cesium salt reaction to a cesium base/fatty acid ester reaction, thus enabling the reaction to occur in ambient conditions in minutes instead of hours. The saponification precipitation process reported here, as a result, does not require a vacuum oven or inert reaction environment in obtaining the cesium precursor, or any part of the reaction. Furthermore, the process creates a hygroscopic byproduct that results in a self-drying synthesis. The obtained perovskite nanocrystals exhibit a blue-green tunable emission that occurs via quantum confinement effect, phase, and morphology change. The consequence of these physical processes is that the band gap is highly tunable with temperature and the resulting nanocrystals show remarkable optical properties, while greatly simplifying the production of halide perovskite nanoplatelets and nanoplates.
关键词： Blue-Green Tunable Emission,Saponification Precipitation Method,Hybrid Materials,Magnetic,CsPbBr3 Nanocrystals,Plasmonics,Optical
更新于2025-11-19 16:46:39
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Precipitation behavior of selective laser melted FeCoCrNiC0.05 high entropy alloy
摘要： Interstitial elements are e?ective to strengthen high entropy alloys (HEAs). In this work, FeCoCrNiC0.05 was prepared by selective laser melting (SLM) followed by annealing. The e?ects of annealing on the microstructures and mechanical properties of the SLMed FeCoCrNiC0.05 were investigated. Results show that, nano-scale Cr23C6-type carbides can precipitate under annealing conditions, leading to higher yielding strength. The SLMed FeCoCrNiC0.05 annealed at 1073 K for 0.5 h has a yielding strength of 787 MPa and an elongation of 10.3%. Precipitation kinetics in SLMed FeCoCrNiC0.05 has been established according to Avrami formula. The high strength can be attributed to solid solution hardening, precipitation hardening and cell-like structures.
关键词： Precipitation kinetics,Hardening mechanism,Selective laser melting,Mechanical properties,High entropy alloy
更新于2025-11-14 17:04:02
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Improving Photovoltaic and Enzymatic-Sensing Performance by Coupling Core-Shell Au Nanorod@TiO2 Heterostructure with Bioinspired L-DOPA Polymer
摘要： The photoelectrochemistry (PEC) performance of TiO2 is somewhat limited by its wide band gap and low quantum efficiency, and the innovation of its composite materials provides a promising solution for an improved performance. Herein, a composite of an Au nanorod@TiO2 core-shell nanostructure (AuNR@TiO2) and a melanin-like L-DOPA polymer (PD) is designed and prepared, where the outer-layer PD tethered by the TiO2-hydroxyl complexation and the AuNR core can intensify the long-wavelength light harvesting, and the AuNR@TiO2 core-shell structure can strengthen the hot-electron transfer to TiO2. The photocurrent of the PD/AuNR@TiO2 is 8.4-fold improved versus that of commercial TiO2, and the maximum incident photon-to-electron conversion efficiency reaches 65% in the UV-visible-near-infrared region. In addition, the novel PD/AuNR@TiO2 photocatalyst possesses the advantages of good biocompatibility and stability, which can act as a versatile PEC biosensing platform for providing biocompatible environment and improving detection sensitivity. Herein, a PEC enzymatic biosensor of glucose is developed on the basis of the immobilization of dual enzyme (glucose oxidase (GOx) and horseradish peroxidase (HRP)) in PD and the signalling strategy of biocatalytic precipitation. In phosphate buffer containing glucose and 4-chloro-1-naphthol, the HRP-catalyzed oxidation of 4-chloro-1-naphthol by GOx-generated H2O2 can form a precipitate on the electrode, by which the decrement of photocurrent intensity is proportional to the common logarithm of glucose concentration. The linear detection range is from 0.05 μM to 10.0 mM glucose, with a limit of detection of 0.01 μM (S/N=3). Glucose in some human serum samples is analyzed with satisfactory results.
关键词： Au nanorod@TiO2 core-shell heterostructure,biocatalytic precipitation,bioinspired L-DOPA polymer,photoelectrochemistry,enzymatic sensing of glucose
更新于2025-11-14 17:04:02
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Interesting makeover of strontium hexaferrites for environment remediation from excellent photocatalysts to outstanding adsorbents via inclusion of Mn3+ into the lattice
摘要： Manganese incorporated strontium hexaferrites with composition SrMnxFe12-xO19 (x= 0.0, 0.4, 0.8, 1.2, 1.6, 2.0, 3.0, 4.0 and 5.0) were fabricated via chemical co-precipitation methodology. Various characterization techniques were employed to investigate the physical properties of the synthesized hexaferrites. Powder X-Ray Diffraction (XRD) patterns revealed the formation of hexagonal phase with P63/mmc space group. FE-SEM micrographs exhibited hexagonal morphology of the synthesized materials; particle size of 125-150 nm range was observed. EDX spectra unveiled the presence of desired elements. The lattice interplanar fringe width from HR-TEM images was observed to be 0.22 nm, 0.26 nm and 0.27 nm indexed to (114), (107) and (203) planes of the manganese doped strontium hexaferrite. Surface area of the synthesized hexaferrites was found to be in the range of ~7.8 to ~8.4 m2/g, scrutinized by Brunauer–Emmet–Teller (BET) plots. Saturation magnetisation values were found to decrease with increase in Mn content from 38.7 to 11.7 emu/g, albeit retaining sufficient magnetic strength to be recovered using an external magnet. Absorption edge for all the hexaferrites was found to lie in the visible region of the spectrum. The oxidation state of different elements present in synthesized hexaferrites was scrutinized using X- ray Photoelectron Spectroscopy (XPS). To explore the catalytic efficiency of the synthesized hexaferrites, photo-fenton degradation of methyl orange (MO), remazol deep red (RDR) and p-nitrophenol (PNP) was employed. All the synthesized hexaferrites were found to be highly proficient, degrading the pollutants upto ~98%. Interestingly, astonishing adsorption of ~92.7 % was showcased by SrMn5Fe7O19, prior to the addition of oxidizing agent indicating the symptomatic transformation from excellent photocatalyst to outstanding adsorbents via incorporation of Mn3+ into the lattice. The maximum adsorption capacity of 56.20 and 112.35 mg/g was observed for MO and RDR, respectively.
关键词： photo-fenton degradation,strontium hexaferrites,adsorption,chemical co-precipitation method,manganese substituted ferrites
更新于2025-11-14 17:03:37
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Detoxification of dye contaminated water by Mn $$^{2+}$$ 2 + -doped ZnS nanostructures
摘要： Chemical co-precipitation route was successfully employed to synthesize polyethylene glycol-coated pure and doped Zn1?x Mnx S (0 ≤ x ≤ 0.1) nanoparticles. The crystallographic and morphological analyses have been done by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The formation of cubic crystal structure and quasi-spherical morphology has been revealed by XRD and TEM, respectively. The optical analyses have been done by UV–Vis absorption spectroscopy and energy resolved photoluminescence spectroscopy. Energy dispersive X-ray spectroscopy study has been carried to analyse the elemental composition. The doping concentration dependent photo-catalytic activity was checked to analyse the photo-catalytic potential of Zn1?x Mnx S nanoparticles under UV irradiation.
关键词： photo-catalytic activity,Chemical co-precipitation,Zn1?x Mnx S nanoparticles
更新于2025-11-14 15:26:12
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Visible Light Assisted Enhanced Photocatalytic Performance of ZnO/NiO Nanocomposites Prepared by Chemical Co-Precipitation Method
摘要： A series of Ni1?xZnxO (x = 0.1 to 0.4) nanocomposites is synthesized by facile chemical co-precipitation method. The structural analysis is carried out using X-ray diffraction (XRD) graph which reveals both cubic (NiO) and hexagonal (ZnO) phases. Chemical bonding, morphology, elemental composition and optical properties of prepared nanocomposites are investigated by Fourier Transform Infrared (FTIR) Spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX), and UV-Vis spectroscopy respectively. FESEM micrographs show the formation of nanorods at higher concentration of zinc content. Introducing higher amount of Zn, optical band gap of composites is considerably reduced. Furthermore, solutions of Rose Bengal (RB) and Methylene Blue (MB) dyes are used to investigate the photocatalytic ability of synthesized samples in the presence of sunlight. It was found that the percentage degradation of dye concentration increases with irradiation time and also with the increase in concentration of zinc in prepared samples.
关键词： Photocatalysis,Co-Precipitation,FESEM
更新于2025-11-14 14:48:53
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Graphene oxide-based zirconium oxide nanocomposite for enhanced visible light-driven photocatalytic activity
摘要： In the present investigation, an efficient visible light-active, graphene oxide-based zirconium oxide nanocomposite (GO–ZrO2) has been synthesized by co-precipitation method. The synthesized photocatalyst was characterized by XRD, FTIR, FE-SEM, EDS, TEM, TGA, PL, UV-DRS and BET surface area analysis. The characterization results illustrate the homogeneous dispersion of ZrO2 nanoparticles in the GO–ZrO2 nanocomposite with excellent harmony between GO and ZrO2 nanoparticles. The photocatalytic efficiency of the synthesized GO–ZrO2 nanocomposite was evaluated by photodegradation of hazardous, water-soluble rhodamine B and methylene blue dyes under visible light irradiation. The 90% photocatalytic degradation of rhodamine B dye (with initial conc. 30 mg/L) was observed in 105 min of visible light irradiation, while 99.23% of methylene blue (with initial conc. 100 mg/L) dyes degradation was observed in just 60 min using 25 mg/100 ml dose of GO–ZrO2 nanocomposite as a photocatalyst. The mechanistic investigation using scavengers suggest that the superoxide (O2·?) is the most reactive species involved in the photodegradation of organic dyes. The synthesized photocatalyst GO–ZrO2 nanocomposite also exhibits excellent thermal stability and reusability.
关键词： Methylene blue,Rhodamine B,Photocatalytic activity,Zirconium oxide,Graphene oxide,Visible light,Co-precipitation method
更新于2025-09-23 15:23:52
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Low-temperature dark anneal as pre-treatment for LeTID in multicrystalline silicon
摘要： Light and elevated temperature induced degradation (LeTID) is currently a severe issue in crystalline silicon photovoltaics, which has led to numerous efforts to both understand the mechanism and to mitigate it. Here we show that a low-temperature dark anneal performed as the last step in typical solar cell processing influences greatly LeTID characteristics, both the strength of the degradation and the degradation kinetics. While a relatively short anneal in the temperature range of 200–240 °C can be detrimental to LeTID by doubling the degradation intensity, an optimized anneal at 300 °C shows the opposite trend providing an efficient means to eliminate LeTID. Furthermore, we show that the simulated recombination activity of metal precipitation and dissolution during the dark anneal correlates with the experiments, suggesting a possible explanation for the LeTID mechanism.
关键词： PERC,Precipitation,Multicrystalline silicon,Minority-carrier lifetime,LeTID,Copper in silicon
更新于2025-09-23 15:23:52
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Photocatalytic treatment of palm oil mill effluent by visible light-active calcium ferrite: Effects of catalyst preparation technique
摘要： Palm oil mill effluent (POME) is a serious and expensive environmental problem in Malaysia. In this paper, CaFe2O4 is introduced as a novel photocatalyst for the degradation of POME under visible light irradiation. Two synthesis routes, auto-combustion and co-precipitation, and two calcination temperatures 550 °C and 700 °C were used to produce four CaFe2O4 catalysts AC550, AC700, CP550 and CP700. CP550 exhibited the greatest photocatalytic degradation at 56% chemical-oxygen-demand (COD) removal after 8 h of irradiation which dropped to 49% after three consecutive cycles indicating reasonable conversion and high recyclability. BET analysis indicated CP550 had the highest SBET (27.28 m2/g) and pore volume (0.077 cm3/g) which dropped precipitously for CP700 upon increasing the calcination temperature to an SBET of 9.73 m2/g and pore volume of 0.025 cm3/g due to annealing which created a smoother surface area as evidenced by the SEM images. UV–Vis DRS indicated CP550 had the highest band-gap (1.52 eV) which is likely due to the presence of a highly crystalline pure CaFe2O4 phase compared to the other products which existed as a mixture of Fe oxidation states evidenced by the XRD data. The PL spectra for all catalysts indicated significantly lower recombination rate for both CP550 and CP700. Introduction of IPA into the reaction mixture to eliminate hydroxyl radicals resulted in a diminishing of COD removal from 56% to 7% proving hydroxyl radicals to be the primary reactive species responsible for photodegradation of POME.
关键词： Co-precipitation,POME,Photocatalysis,Visible light,Calcium ferrite,Auto-combustion
更新于2025-09-23 15:23:52
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Studies on structural and optical properties of pure and transition metals (Ni, Fe and co-doped Ni–Fe) doped tin oxide (SnO2) nanoparticles for anti-microbial activity
摘要： In this present work, pure and transition metal ions (Ni, Fe and co-doped Ni–Fe) doped SnO2 nanoparticles (NPs) were synthesized using a simple chemical co-precipitation method. Transition metal ions (Ni, Fe and co-doped Ni–Fe) were doped in order to study the influence of structural and optical properties. The synthesized samples were analyzed by using powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, UV–Visible spectroscopy, FT-IR, and photoluminescence spectroscopic techniques. SnO2 crystallites were found to exhibit tetragonal rutile structure with space group P42/mnm (136) with average particle size in the range of 20–30 nm. Also confirmed that all the doped metal ions were incorporated to SnO2. The UV–Vis-NIR spectroscopy revealed a significant red shift in the absorbing band edge due to increase in the amount of Ni, Fe and co-doped Ni–Fe contents. The SEM image shows the morphology of pure and doped (Fe, Ni and Fe–Ni co-doped) SnO2 NPs with large spherical shapes. In FT-IR spectra, the strong peaks are attributed to the antisymmetric stretching mode of O-Sn-O. The PL spectrum exhibits a strong blue emission peak. The antimicrobial studies were investigated against standard bacterial strains and enhanced anti-bacterial activity in doped and co-doped samples was observed, which can be attributed to the ROS and the particles were in the nanoscale regime.
关键词： Antibacterial activity,Photoluminescence,Co-precipitation,Nanoparticle,Co-dopant
更新于2025-09-23 15:23:52