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Green Preparation of Fluorescent Carbon Quantum Dots from Cyanobacteria for Biological Imaging
摘要： Biomass-based carbon quantum dots (CQDs) have become a significant carbon materials by their virtues of being cost-effective, easy to fabricate and low in environmental impact. However, there are few reports regarding using cyanobacteria as a carbon source for the synthesis of fluorescent CQDs. In this study, the low-cost biomass of cyanobacteria was used as the sole carbon source to synthesize water-soluble CQDs by a simple hydrothermal method. The synthesized CQDs were mono-dispersed with an average diameter of 2.48 nm and exhibited excitation-dependent emission performance with a quantum yield of 9.24%. Furthermore, the cyanobacteria-derived CQDs had almost no photobleaching under long-time UV irradiation, and exhibited high photostability in the solutions with a wide range of pH and salinity. Since no chemical reagent was involved in the synthesis of CQDs, the as-prepared CQDs were confirmed to have low cytotoxicity for PC12 cells even at a high concentration. Additionally, the CQDs could be efficiently taken up by cells to illuminate the whole cell and create a clear distinction between cytoplasm and nucleus. The combined advantages of green synthesis, cost-effectiveness and low cytotoxicity make synthesized CQDs a significant carbon source and broaden the application of cyanobacteria and provide an economical route to fabricate CQDs on a large scale.
关键词： bioimaging,cyanobacteria,carbon quantum dots,hydrothermal method
更新于2025-11-21 11:08:12
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Architectural Design of Photodetector Based on 2D (MoS <sub/>2</sub> ?Nanosheets)/1D (WS <sub/>2</sub> ?Nanorods) Heterostructure Synthesized by Facile Hydrothermal Method
摘要： Hydrothermal technique is utilized to synthesize 2D/1D heterostructure based on MoS2 (nanosheets)/WS2 (nanorods) for photodetector application. The sensor was fabricated by drop cast technique. X-Ray Diffraction (XRD), Fourier Transform Infra-red (FTIR) Spectroscopy, Field-Emission Scanning Electron Microscopy (FESEM), UV-Visible (Uv-Vis), Raman and X-Ray Photoelectron spectroscopy (XPS) were performed to characterize the synthesized sample. The optical sensor based on heterostructure was studied as a function of laser wavelength (λex): 635 nm (red), 785 nm (infra-red) and 1064 nm (near infra-red) and power of illuminated laser sources. The device exhibits photoresponsivity in a broadband range from the visible to the near-infrared (600–1065 nm, yield a photoresponsivity (Rp) = 15 μA/W and high speci?c detectivity (D?) = 24 × 106 jones at λex = 785 nm). The photoresponsive characteristics of MoS2/WS2 heterostructure hold the principle of simple power law.
关键词： MoS2 nanosheets,photodetector,hydrothermal method,WS2 nanorods,2D/1D heterostructure
更新于2025-11-21 11:01:37
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A high-performance room temperature methanol gas sensor based on alpha-iron oxide/polyaniline/PbS quantum dots nanofilm
摘要： A high-performance room temperature methanol gas sensor based on alpha-iron oxide/polyaniline/lead sulfide quantum dots (α-Fe2O3/PANI/PbS QDs) nanofilm was demonstrated in this paper, among which the α-Fe2O3 was an urchin-shaped hollow microsphere. The sensing film was fabricated on an epoxy substrate with interdigital electrodes via successive ionic layer adsorption and reaction technique. The prepared α-Fe2O3/PANI/PbS QDs nanocomposite was examined by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, scanning election microscopy and Fourier transform infrared spectrum. The methanol sensing performances of the α-Fe2O3/PANI/PbS QDs film sensor were investigated against methanol from 10 to 100 ppm at room temperature. The experimental results indicated that the methanol sensor in this work had an excellent response, outstanding selectivity and good repeatability at room temperature. The underlying sensing mechanism of the α-Fe2O3/PANI/PbS QDs film toward methanol was ascribed to a series of interactions and changes on the surface of thin films, which make their resistance change greatly. Larger surface area and much more active adsorption sites also played an important role.
关键词： Methanol gas sensor,Room temperature,Successive ionic layer adsorption and reaction,Hydrothermal method,α-Fe2O3/PANI/PbS QDs
更新于2025-11-14 17:15:25
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Graphene oxide/ZnO nanorods/graphene oxide sandwich structure: The origins and mechanisms of photoluminescence
摘要： In this paper, we present the structural and optical properties of Graphene oxide/ZnO nanorods/graphene oxide (GO/ZnO nanorods/GO) nanocomposites prepared via a hydrothermal method on Si (100) substrate. The X-ray diffraction measurements (XRD) confirm that the prepared samples are of hexagonal wurtzite structure with crystallite size around 50-60 nm. It was obvious from scanning electron microscopy (SEM) that by incorporating the ZnO nanorods between the inter-layer of GO confirmed the formation of sandwich-like nanocomposites structure. ZnO nanorods interaction with GO is displayed by the different vibrational frequencies in fourier transform infrared spectroscopy (FTIR). The UV-Vis spectrum reveals the strongest absorption was observed around 370 nm, while calculating optical band gap energy (Eg) of GO/ZnO NRs/GO was found to be 3.15 eV. The photoluminescence (PL) measurements indicates that the ZnO nanorods have a strong visible emission centered at 559 nm attributed to the presence of impurities in the form of oxygen vacancies. After the nanorods were covered with GO layers, the PL intensity of the nanocomposite is quenched and shifted due to charge-transfer process. Consequently, the obtained results may lead to better performance for the optoelectronic applications.
关键词： ZnO nanorods,hydrothermal method,excitation effect,graphene oxide
更新于2025-11-14 15:25:21
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Fabrication and enhanced photocatalytic property of TiO2-ZnO composite photocatalysts
摘要： TiO2 nanotube and TiO2-ZnO composite photocatalysts were fabricated by simple hydrothermal method, and the photocatalytic property of as-prepared samples were analyzed by the photo degradation of rhodamine B water solutions under visible light irradiation. The prepared TiO2-ZnO composite photocatalysts exhibited excellent property in photo degradation of rhodamine B water solution, which is better than that of P25. The enhancement photocatalytic property of target photocatalysts could be attributed to the reduced band gap energy, the enhanced-surface physic-chemical properties, the separation of photo induced electron-hole pairs and the decreased recombination rate. In addition, TiO2-ZnO composite photocatalysts showed good stability for rhodamine B photo degradation under visible light.
关键词： Microstructure,TiO2-ZnO,Photocatalytic property,Hydrothermal method,Composite materials
更新于2025-09-23 15:23:52
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Fabrication of an electrochromic device by using WO3 thin films synthesized using facile single-step hydrothermal process
摘要： The development of an uncomplicated process for the preparation of tungsten oxide (WO3) nanorods (NRs) using hydrothermal method is still underway. Thus, this study demonstrated the growth of WO3 NRs on indium tin oxide (ITO) coated glass substrates in aqueous solution using single synthesis step hydrothermally. The surface area and size of the NRs which should be tunable for electrochromic (EC) applications were controlled by adjusting the concentration of surfactants such as propylene glycol (PG). The synthesized NRs were illustrated using crystal structure study, surface morphology, chemical analysis, and the measure of the luminance of a color. The results manifested that increasing the PG content increased the size of the crystallite with a nanoparticle-like morphology on the ITO substrate, indicating the direct deposition of a stable WO3 thin film. In addition, the synthesized WO3 NRs exhibited fast switching speed and high contrast ratio implying superior EC properties for smart window application. Furthermore, an EC device with the dimensions of 2×4 cm2 was assembled using the synthesized WO3 NRs with the ITO/WO3/Lithium perchlorate-propylene carbonate-poly(methyl methacrylate)-acetonitrile/nickel oxide/ITO configuration. The device had an average optical modulation in the visible region, a fast EC response time (1.2 s for coloration and 1.5 s for decoloration), excellent coloration efficiency (243 cm2 C-1) and a superior EC stability (over 20000 color/decolor cycles).
关键词： nanorod,tungsten trioxide,single-step method,Hydrothermal method,electrochromic device
更新于2025-09-23 15:22:29
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Enhanced UV-light driven photocatalytic performances and recycling properties of TiO2/AlON composite photocatalyst
摘要： AlON has been reported to have photocatalytic capability under ultraviolet-light (UV-light), which can be improved by fabricating large-sized powder (~20 μm) having porous skeleton microstructure. To further enhance photocatalytic property of AlON, highly photocatalytic-efficient nanocrystalline TiO2 was loaded onto both the outer and inner surface of porous AlON particles by hydrothermal method. In order to ensure easy recovery without secondary pollution, the obtained composite powder was filtered in deionized water three times to remove both small-sized AlON and free TiO2 particles to produce a composite photocatalyst with particle size > 10 μm. The proposed TiO2/AlON showed excellent photocatalytic performance on Methylene blue (MB) and Methyl orange (MO) for 97.9% and 99.1% of pollutants (in 30 mg/L, 40 mL solution) being degraded by 50 mg as-synthesized composite photocatalyst in 120 min. Further test showed that the hydrothermal process can significantly improve the photocatalytic performance of TiO2/AlON composite photocatalyst and its enhancement mechanism were discussed. In addition, the large-sized composite photocatalyst is easy to recover and stable to reuse with no regeneration needed.
关键词： Hydrothermal method,Composite photocatalyst,TiO2/AlON,UV-light
更新于2025-09-23 15:22:29
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Enhanced Ultraviolet Emission from Hydrothermally Grown ZnO Nano-Grass on Si Substrate
摘要： Highly crystalline one-dimensional zinc oxide (ZnO) nano-grass was grown on silicon (Si) substrate by a modified hydrothermal method. A predominantly c-oriented ZnO nano-grass with an average diameter of 40–60 nm and length of 1.5–2.0 lm was obtained. From the photoluminescence (PL) measurement, we observed a defect-free, intense ultraviolet emission of as-grown ZnO nano-grass, confirming the absence of singly ionized oxygen vacancies. The absence of green deep-level emission in the PL spectrum further implies a high crystallinity of as-grown ZnO nano-grass. The high-quality ZnO nano-grass has potential applications in single nanowire-based light-emitting diodes, solar cells, themoresistive sensing, photocatalysis, ultraviolet photodetectors, optical switches, waveguides and nano-lasers.
关键词： photoluminescence,ZnO nanowires,annealing process,ultraviolet emission,hydrothermal method
更新于2025-09-23 15:22:29
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The effects of Tb doped ZnO nanorod: An EPR study
摘要： Structural and magnetic behaviors were studied and correlated with each other for Zn1?xTbxO nanorods synthesized by hydrothermal method varying x values from 0.01 to 0.05 with 0.01 step increment. The structural properties of Zn1?xTbxO nanorods were determined by X-ray diffraction tool. All nanorods were found as a single phase with ZnO wurtzite hexagonal structure. The concentration-dependent of lattice parameters, cell volumes, microstrain, stress, dislocation density, the locality of the atoms and their displacements, and bond length in Zn1?xTbxO (where x = 0.0, 0.01, 0.02, 0.03, 0.04, and 0.05) structures were detailed. The particles with varying magnifications were observed as random agglomeration using Scanning Electron Microscope measurement tool. ESR spectra of Zn1?xTbxO were collected at room temperature on a Bruker EMX model X-band spectrometer operating at a frequency of 9.71 GHz. ESR measurements have been performed and analyzed through concentration dependence of the g-factor and the line-widths of pike to pike (ΔHPP) of ESR spectra. Experimental and fitting X-band ESR spectra of Tb doped ZnO nanorods with a different doping concentration of Tb recorded at room temperature were presented.
关键词： Hydrothermal method,Magnetic properties,Nanorods,Zn1?xTbxO
更新于2025-09-23 15:22:29
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BaV2O6·H2O: A nonlinear optical crystal with a large bandgap
摘要： The first Ba-containing hydrated vanadate as nonlinear optical (NLO) material, BaV2O6·H2O, was synthesized by facile hydrothermal method. The single-crystal X-ray diffraction result shows that this compound crystallizes in the acentric orthorhombic space group of P212121 with cell parameters a = 7.3993(6) ?, b = 8.9934(7) ?, and c = 9.7206(8) ?. UV–vis-IR diffuse reflectance spectrum shows that the compound has a large bandgap of 4.60 eV and moderate transparency range. The title compound shows second-harmonic generation (SHG) efficiency about 0.5 times of KH2PO4 (KDP). The structure-property relationship of BaV2O6·H2O was clarified by the first-principles studies.
关键词： Vanadate,Nonlinear optical material,Large bandgap,Hydrothermal method
更新于2025-09-23 15:22:29