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A hydrothermally synthesized MoS <sub/>2(1a??x)</sub> Se <sub/>2x</sub> alloy with deep-shallow level conversion for enhanced performance of photodetectors
摘要： Photoelectric detectors based on binary transition metal chalcogenides have attracted widespread attention in recent years. However, due to the high-temperature synthesis of binary TMD, high-density deep-level defect states may be generated, leading to poor responsiveness or a long response time. Besides, the addition of an alloy will change the DLDSs from deep to shallow energy levels caused by S vacancies. In this paper, MoS2(1?x)Se2x nanostructures were synthesized by a hydrothermal method, and a novel type of photodetector was fabricated by using the synthesized material as a light sensitive material. The MoSSe-based photodetector not only has a high photocurrent, but also exhibits a wide spectral response in the range of 405 nm to 808 nm. At the same time, it can achieve a responsivity of 1.753 mA W?1 under 660 nm laser irradiation of 1.75 mW mm?2. Therefore, this work can be considered as a method of constructing a new type of photodetector with a simple process and low cost.
关键词： MoS2(1?x)Se2x,photoelectric detectors,photodetector,transition metal chalcogenides,hydrothermal synthesis
更新于2025-09-23 15:21:01
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Multi-cycle Growth of Boron Doped ZnO Films as Photoanode for Dye-Sensitized Solar Cell (DSSC)
摘要： The work is concerned with the fabrication of dye sensitized solar cell (DSSC) utilizing multi-layer boron doped ZnO nanorods films. The B-doped ZnO films were prepared on FTO glass substrate via seed mediated hydrothermal method. Multi-layer B-doped ZnO nanorods were obtained by immersing the sample into a growth solution and repeated the growth process at 90 oC for 30 minutes. The structure of the B-doped ZnO film has been found to exhibit the hexagonal wurtzite structure. The length and diameter of the nanorods increase with the number of the growth cycle. The performance of the DSSC fabricated using the multi-layer B-doped ZnO nanorod was found to be significantly higher than that of the DSSC based on the single layer ZnO nanorod arrays. The best photovoltaic parameters with the JSC of 3.5 mA cm-2, FF of 0.38 and η of 0.67%, respectively was obtained for the device utilizing the layer with 3 cycles since it possesses the lowest photoluminescence in visible region and lowest Rct.
关键词： nanorod,boron,dye-sensitized solar cell,ZnO,hydrothermal
更新于2025-09-23 15:21:01
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Magneto-optical properties of Rare Earth metals substituted Co-Zn spinel nanoferrites
摘要： Cobalt–zinc ferrite nanoparticles (NPs) substituted with three different metals, Co0.5Zn0.5RexFe2-xO4 (RE = Ce, Dy, and Y; 0.00 ≤ x ≤ 0.05) were prepared hydrothermally. Fourier Transform-Infrared (FT-IR) Spectroscopy, X-ray powder diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDX) and Vibrating Sample Magnetometry (VSM) analyzed the products. The formation of cubic phase of spinel Co-Zn ferrite NPs were confirmed through XRD, FT-IR and FE-SEM techniques. The structural investigation of NPs by XRD revealed that the lattice parameter "a" decreases with the introduction of the RE in the ferrite structure by the substitution of Fe3+ by RE ions. The different magnetic parameters of Co0.5Zn0.5RexFe2-xO4 (RE = Ce, Dy, and Y; 0.00 ≤ x ≤ 0.05) NPs such as the saturation magnetization, coercivity, remanence, and magnetic moment were calculated and discussed in relation to structure and microstructure properties. M (H) hysteresis curves indicated that the samples exhibit superparamagnetic nature at room temperature. A slight improvement in the magnetization was obtained especially for the Ce- and Y-substituted Co0.5Zn0.5Fe2O4 (CZF) NPs at a certain RE level. However, the case Dy-substituted CZF products showed a sharp decrease in the magnetization with x > 0.01. The results are mostly ascribed to the substitution of smaller Fe3+ ions with larger RE3+ ions.
关键词： Spinel ferrites,Morphology,Rare earth substitution,Hydrothermal,Magnetic properties
更新于2025-09-23 15:21:01
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Morphological, spectroscopic and photocatalytic properties of Eu3+:TiO2 synthesized by solid-state and hydrothermal-assisted sol-gel processes
摘要： Eu3+ doped TiO2 powders were synthesized by solid-state reaction and hydrothermal-assisted sol-gel process. They were characterized by X-ray diffraction, scanning electron microscopy and photoluminescence techniques. Both synthetic procedures yield the pure anatase phase of titania. The excitation and emission spectra and the decay profiles were measured for different thermal treatments of the samples, in order to investigate the effects of the synthesis conditions on the doping mechanism. The photocatalytic activity was investigated by measuring the degradation of methylene blue under UV light irradiation and a correlation between its efficiency and the luminescence performance has been proposed.
关键词： TiO2:Eu,Solid-state,Optical spectroscopy,Anatase,Photocatalysis,Hydrothermal-assisted sol-gel
更新于2025-09-23 15:21:01
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Nanosheets-assembled Bi2WO6 microspheres with efficient visible-light-driven photocatalytic activities
摘要： The nanosheet-assembled Bi2WO6 microspheres could be successfully synthesized in large quantities by a facile hydrothermal strategy in the presence of surfactant hexadecyl trimethyl ammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) under mild conditions. The morphology and size of as-prepared Bi2WO6 could be readily controlled by adjusting the synthetic parameters such as hydrothermal time. The probable formation mechanism of nanosheet-assembled Bi2WO6 microspheres was discussed in detail. The hierarchical nanosheet-assembled microspheres could be constructed by orderly arranged nanosheets. The photocatalytic activity of the nanosheet-assembled Bi2WO6 microspheres was evaluated by degrading rhodamine B (RhB) under irradiation of visible light. The brilliant photodegradation e?ciency is about 98% under visible light irradiation for 50 min. The results suggest that the as-prepared Bi2WO6 microspheres have good prospects as the photocatalyst for the removal of organic pollutants.
关键词： Hydrothermal,Bi2WO6,Visible light,Nanosheets,Microspheres,Photocatalysis
更新于2025-09-23 15:21:01
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Preparation of graphene quantum dots with high quantum yield by a facile one-step method and applications for cell imaging
摘要： The preparation and biological applications of graphene quantum dots (GQDs) have attracted much attention. Here, a one-step hydrothermal method for synthesizing nitrogen-doped GQDs (N-GQDs) using graphene oxide (GO), ethylenediamine and hydrogen peroxide, simultaneously achieved oxidative cleavage and chemical reduction of GO. The average size of the synthesized N-GQDs was about 1.84±0.28 nm and their quantum yield of the N-GQDs reached about 0.46, which was higher than that of other GQDs synthesized by top-down methods. The cytotoxicity of these N-GQDs on Hela cells was evaluated using a cell counting Kit-8 assay. The effects of N-GQDs on different cell lines and fluorescence imaging were also observed by confocal laser scanning microscopy. The results suggested that these N-GQDs penetrated into cells by endocytosis and were promising fluorescent probes for biological imaging.
关键词： Carbon materials,Hydrothermal reaction,Luminescence,Graphene quantum dots,Bio-imaging
更新于2025-09-23 15:21:01
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Fabrication and photoluminescent properties of Tb3+ doped carbon nanodots
摘要： Carbon nanodots (CNDs) doped with Tb ions were synthesized using different synthetic routes: hydrothermal treatment of a solution containing carbon source (sodium dextran sulfate) and TbCl3; mixing of CNDs and TbCl3 solutions; freezing-induced loading of Tb and carbon-containing source into pores of CaCO3 microparticles followed by hydrothermal treatment. Binding of Tb ions to CNDs (Tb-CND coupling) was confirmed using size-exclusion chromatography and manifested itself through a decrease of the Tb photoluminescence lifetime signal. The shortest Tb photoluminescence lifetime was observed for samples obtained by hydrothermal synthesis of CaCO3 microparticles where Tb and carbon source were loaded into pores via the freezing-induced process. The same system displays an increase of Tb photoluminescence via energy transfer with excitation at 320–340 nm. Based on the obtained results, freezing-induced loading of cations into CNDs using porous CaCO3 microparticles as reactors is proposed to be a versatile route for the introduction of active components into CNDs. The obtained CNDs with long-lived emission may be used for time-resolved imaging and visualization in living biological samples where time-resolved and long-lived luminescence microscopy is required.
关键词： freezing-induced loading,Tb3+ doping,photoluminescence,hydrothermal treatment,Carbon nanodots,CaCO3 microparticles
更新于2025-09-23 15:21:01
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{0 0 1}-Facet-Exposed Ag <sub/>4</sub> V <sub/>2</sub> O <sub/>7</sub> Nanoplates: Additive-Free Hydrothermal Synthesis and Enhanced Photocatalytic Activity
摘要： The synthesis of silver pyrovanadate, Ag4V2O7, nanoplates with exposed {0 0 1}-facets by a facile, additive-free hydrothermal method was described in this paper. The photocatalytic activity of rhodamine B over Ag4V2O7 samples under solar light irradiation was also evaluated. By using an equimolar mixture of NH4VO3 and AgNO3 with the presence of a suitable amount of ammonia, Ag4V2O7 nanoplates were obtained readily and purely at temperatures from 100 to 140°C for 4 h. The c-axis orientation growth of Ag4V2O7 nanoplates occurred and increased monotonously with temperatures in the range of over 100 up to 140°C. Further increase in hydrothermal temperature up to 220°C, the Ag4V2O7 phase no longer existed and the β-AgVO3 phase was formed instead. The photocatalytic activity of the optimized Ag4V2O7 sample comprising {0 0 1}-facet-exposed nanoplates with the highest degree of orientation was significantly higher than that of the random-oriented sample. The effects of using ammonia as a complexing agent on the structure, microstructure, texture, exposed facet, and photocatalytic activity of Ag4V2O7 samples were also investigated for the first time.
关键词： photocatalytic activity,hydrothermal synthesis,Ag4V2O7,rhodamine B,nanoplates,solar light irradiation
更新于2025-09-23 15:21:01
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Induced Photonic Response of ZnO Nanorods Grown on Oxygen Plasma-Treated Seed Crystallites
摘要： We examined the influence of O2 plasma treatment for the ZnO seed layer (SL) crystallites on the material characteristics of ZnO nanorods (NRs) synthesized by the hydrothermal method. Diode photocurrent and photo-response transient characteristics of the p-Si/n-ZnO-NR heterojunction-based ultraviolet (UV) photodetectors were also examined according to the plasma treatment for the SLs. The superior optical properties of NRs were measured from the photoluminescence by exhibiting 4.6 times greater near-band edge emission when grown on the O2-plasma-treated SL. The degree of (002) orientation of the NR crystals was improved from 0.67 to 0.95, as revealed by X-ray diffraction analysis, and a higher NR surface density of ~80 rods/μm2 with a smaller mean diameter of 65 nm were also observed by the SL modification using plasma-treatment. It was shown by X-ray photo-electron spectroscopy that this improvement of NR crystalline quality was due to the recovery of stoichiometric oxygen with significant reduction of oxygenated impurities in the SL crystals and the subsequent low-energy growth mode for the NRs. UV PDs fabricated by the proposed SL plasma treatment technique showed significantly enhanced UV-to-dark current ratio from 2.0 to 83.7 at a forward bias of +5 V and faster photo-response characteristics showing the reduction in recovery time from 16 s to 9 s.
关键词： photoluminescence,surface defects,oxygen plasma,ZnO seed crystals,hydrothermal
更新于2025-09-23 15:21:01
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Effect of the Synthesis Method on the Properties of Ultrafine YAG Powder
摘要： Yttrium aluminum garnet (YAG) materials have a number of unique properties, such that its application is extensive. In this study, ultrafine YAG powder materials were prepared by coprecipitation and hydrothermal precipitation methods. The influence of the synthesis process on the morphology of the powder was investigated. Results showed that the precursor powder prepared via the coprecipitation method mainly undergoes amorphous to crystalline transition with the increase in calcination temperature and that the precursor agglomeration is severe. In the process of increasing the calcination temperature, the dispersibility of the roasted powder is considerably improved, which is favorable for the growth of the crystal grains, such that the particle size of the powder is gradually increased. The YAG precursor prepared by the coprecipitation method is transformed into YAG crystals, with the phase transition mainly occurring between 900 °C and 1,100 °C. When the molar ratio of salt to alkali is Y3+/OH?=1:8 via the hydrothermal reaction, YAG particles with homogeneous morphology can be obtained. When the molar ratio of salt to alkali is continuously increased, the morphology of YAG particles is not obviously changed. The coprecipitation method is used to control the particle size, whereas the hydrothermal method is used to control the particle morphology.
关键词： co-precipitation method,hydrothermal precipitation method,ultra-fine powder,YAG
更新于2025-09-23 15:21:01