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Gas sensing performance of GaOOH and β-Ga<sub>2</sub>O<sub>3</sub> synthesized by Hydrothermal method: A comparison
摘要： Gallium Oxy Hydrate (GaOOH) and β-Ga2O3 nanostructures in submicron scale have been synthesized at low temperature by surfactant-free hydro-thermal method. First, GaOOH has been synthesized using Gallium nitrate anhydrate, Ammonium hydroxide as precursors and double distilled water as solvent. As obtained GaOOH powders have been characterized by XRD, FE–SEM, UV–VIS, Thermo Gravimetric Analysis, I-V characteristics and BET surface analysis in order to reveal their structural, morphological, optical, thermal, electrical and surface properties. FE-SEM micrographs confirm the rod like and needle like morphologies of GaOOH and β- Ga2O3 samples, respectively. Porous nature of the samples observed through BET and BJH analyses. Synthesized GaOOH and β-Ga2O3 powders have been subjected to room temperature CO2 gas sensing in the range, 2000 ppm – 10000 ppm. GaOOH showed quick response of 80 s and fast recovery of 129 s at 8000 ppm while β-Ga2O3 showed quick response of 52 s at 8000 ppm and faster recovery of 98 s at 4000 ppm. Also, the repeatability studies were done for GaOOH and β-Ga2O3 films by exposing to different CO2 concentrations for a period of 6 consecutive days. β-Ga2O3 showed enhanced CO2 sensing response than that of GaOOH due to its better structural, electrical, morphological and surface properties.
关键词： Gallium Oxide (Ga2O3),Gallium Oxide Hydroxide (GaOOH),Hydrothermal method,Characterization,Room temperature CO2 sensing
更新于2025-09-23 15:21:21
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Phase transformation and photoluminescence of undoped and Eu3+-doped zinc stannate (Zn2SnO4) nanocrystals synthesized by hydrothermal method
摘要： In this work we report a hydrothermal approach for synthesis of zinc stannate (Zn2SnO4–ZTO) nanocrystals. Structural properties and morphology of the samples were investigated in detail. In particular, our research focused on the effect of hydrothermal duration on the phase composition of ZTO nanocrystals. By combining X-ray diffraction analysis, scanning electron microscopy and selected area energy-dispersive X-ray spectroscopy, a crystalline phase transformation during the hydrothermal process was enlightened. The ZTO nanocrystals were doped with europium ions. The room-temperature emission spectra of the undoped ZTO and Eu3+-doped ZTO nanocrystals were recorded. The emission spectra of the undoped ZTO nanocrystals showed two broad bands related to the lattice defects, while the spectra of Eu3+-doped ZTO nanocrystals exhibited the narrow emission peaks, which were assigned to the radiative intra-configurational f–f transitions of Eu3+ ions.
关键词： nanocrystals,europium doping,hydrothermal method,photoluminescence,zinc stannate
更新于2025-09-23 15:21:21
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Si, N-codoped carbon dots: preparation and application in iron overload diagnosis
摘要： Heteroatom doping is a straightforward and smart strategy to improve the fluorescence efficiency of carbon dots (CDs). We synthesized the Si, N-codoped CDs (SiNCDs) with high quantum yield up to 29.7% through one-step hydrothermal method. The linear range for Fe3+ was between 0 and 200 μM, and the limit of detection was about 5 μM, which presented potential for Fe quantification in serum to diagnose Fe overload. In addition, the SiNCDs demonstrated good selectivity to Fe3+ among high concentrations of metal ions, amino acids and H2O2, so there is no need to mix additional reagents as the colorimetric method does in clinic, making SiNCDs more competitive in clinical application. Furthermore, we explored the practicability of SiNCDs by detecting Fe in serum from five healthy volunteers and three patients suffering Fe overload. The recovery rate was from 87.1 to 113.6%, which confirmed the application prospect of SiNCDs in clinical diagnostics.
关键词： N-codoped carbon dots,hydrothermal method,Si,iron overload diagnosis,fluorescence efficiency,quantum yield
更新于2025-09-23 15:21:21
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Effects of Nd, Al Doping on the Structure and Properties of BiFeO3
摘要： The BiFeO3(BFO) and Bi0.95Nd0.05Fe1-xAlxO3 (x = 0, 0.03, 0.05, 0.075, 0.1) powders were prepared at 200 °C for 24 h by hydrothermal method. The effects of Al doping content on the structure, morphology, magnetic, and photocatalytic properties were studied. X-ray diffraction (XRD) and Fourier transform infrared spectrometer (FTIR) demonstrated the compounds are distorted rhombohedral perovskite structure without any other heterogeneity and structural transition. Field emission scanning electron microscope (FESEM) reflected surface of compounds is a dense, agglomerated sphere. As the concentration of Al3+ increases, a small part of the spherical crystallites eventually becomes cauliflower shape. Energy-dispersive X-ray (EDS) showed the Bi0.95Nd0.05Fe0.95Al0.05O3 sample mainly consists of five elements (Bi, Fe, O, Nd, Al) and atom radio matched well with the formula. Vibrating sample magnetometer (VSM) integrated in a physical property measurement system (PPMS-9) illustrated introducing Nd3+ ions into BFO will enhance its magnetism at room temperature. However, with the increase of non-magnetic ion Al3+ concentration in Bi0.95Nd0.05Fe1-xAlxO3 (x = 0, 0.03, 0.05, 0.075, 0.1), the network structure of Fe-O-Fe was destroyed, which led to the decrease of its net magnetization, so that the hysteresis loop shows paramagnetism. The photocatalytic performance of BFO increased initially and decreased afterwards as Al3+ concentration increased, and the best catalytic performance was achieved at x = 0.05.
关键词： Hydrothermal method,Magnetism,Nd, Al doping,BiFeO3
更新于2025-09-23 15:21:21
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Effect of Molecular Weight of Polyethylene Glycol on the Sheet-thickness and Photocatalytic Performance of MoS2 Nanoparticles
摘要： Molybdenum disulfide (MoS2) nanomaterials have attracted considerable attention recently owing to its unique photoelectrochemistry property and promising applications in the conversion of solar energy to chemical energy and environmental purification. Flower-like MoS2 photocatalyst was synthesised via hydrothermal method in this work. To achieve the MoS2 nanoparticles with various sheet-thickness, polyethylene glycols (PEG) with deferent molecular mass were employed as additives in the preparation process. The effects of the molecular weight of PEG on the micro structure and crystal structure of MoS2 nanoparticles were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscope (HRTEM) and X-ray diffraction (XRD). The photocatalytic properties of as-synthesized products were evaluated by the degradation of methylene blue (MB) under ultraviolet irradiation. The results suggest that the molecular weight of PEG could affect the sheet thickness of the MoS2 particles. In addition, the degradation rate of MB show that the photocatalytic performance of MoS2 nanoparticles is closely related to their sheet thickness, the photocatalytic activity reduced with the decrease of sheet thickness of MoS2 nanoparticles which is mainly attributed to the reduction of the active sites.
关键词： Photocatalytic performance,MoS2 nanoparticles,Hydrothermal method,PEG,molecular weight,Sheet-thickness
更新于2025-09-23 15:21:01
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Femtosecond-laser-irradiation-induced structural organization and crystallinity of Bi2WO6
摘要： controlling the structural organization and crystallinity of functional oxides is key to enhancing their performance in technological applications. in this work, we report a strong enhancement of the structural organization and crystallinity of Bi2Wo6 samples synthetized by a microwave-assisted hydrothermal method after exposing them to femtosecond laser irradiation. X-ray diffraction, UV-vis and Raman spectroscopies, photoluminescence emissions, energy dispersive spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy were employed to characterize the as-synthetized samples. To complement and rationalize the experimental results, first-principles calculations were employed to study the effects of femtosecond laser irradiation. Structural and electronic effects induced by femtosecond laser irradiation enhance the long-range crystallinity while decreasing the free carrier density, as it takes place in the amorphous and liquid states. these effects can be considered a clear cut case of surface-enhanced Raman scattering.
关键词： structural organization,Bi2WO6,femtosecond laser irradiation,crystallinity,microwave-assisted hydrothermal method
更新于2025-09-23 15:19:57
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Morphology Effect of 1D ZnO Nanostructures Designed by Hydrothermal and Thermal Annealing for Fast Ultraviolet Photodetector Applications
摘要： Zinc oxide (ZnO) nanorods were grown on a ZnO seed layer using the hydrothermal method and subsequently annealed at temperatures of 400–800 °C. The ZnO nanorods annealed at 400 °C exhibited morphology similar to that of the unannealed ZnO nanorods. However, the tips of the ZnO nanorods gradually became rounded and their density and diameter increased with an increase in the annealing temperature. The intensity of the near-band-edge emission increased gradually with an increase in the annealing temperature from 400 to 600 °C but decreased sharply in the case of the nanorods annealed at 800 °C. With respect to the deep-level emissions, broad yellow, orange, and green emissions were observed. Further, the low-temperature photoluminescence spectrum measured at 12 K of the ZnO nanorods annealed at 600 °C contained a donor-bound exciton emission, as well as emissions related to the donor-acceptor pair transition and the first-order and second-order longitudinal optical phonon replicas of the donor-acceptor pair transition. Finally, with respect to the photoresponse, the dark current and photocurrent of the nanorods decreased and their photosensitivity increased with the increase in the annealing temperature.
关键词： Ultraviolet photodetector,Zinc oxide,Photosensitivity,Photoluminescence,Hydrothermal method
更新于2025-09-23 15:19:57
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Superficial preparation of biocompatible carbon quantum dots for antimicrobial applications
摘要： Orange waste peel CQDs has been synthesized via simple hydrothermal method. The UV–visible spectrum shows near band edge absorbance and optical energy bandgap has been calculated as 3.44 eV and 5.60 eV. In addition, the antibacterial assay of CQDs was carried out against two kind of bacteria such as gram positive and gram-negative bacteria. It has been noted that the CQDs show good antibacterial activity towards the gram-negative bacterium Pseudomonas aeruginosa (ZOI: 30 mm). Antibacterial activity of natural waste CQDs was compared with chemically synthesized NPs and QDs.
关键词： Tauc’s plot,CQDs,Hydrothermal method,Electron microscopy,Antibacterial assay
更新于2025-09-23 15:19:57
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Effect of seed layer on growth of rutile TiO <sub/>2</sub> nanorods
摘要： For achieving the high quality of titanium dioxide (TiO2) nanorods, herein, we present a synthesis of rutile TiO2 nanorods on a transparent conductive fluorine-doped tin oxide (FTO) glass substratewith seed layer by a two-step method. TiO2 thin films were first precoated by spin coating and annealing, followed by the growth of TiO2 nanorods with a hydrothermal method. The crystallographic nanostructures and properties of the nanorods were investigated. XRD results demonstrate that seed layer was tetragonal anatase TiO2 structure while nanorods had tetragonal rutile TiO2 structure. Since the hydrothermal technique was conducted in medium acid, structure of nanorods was induced to form in rutile phase. The major characteristic orientation of nanorods on the seed layers was (002) and minor in (101) planes. FE-SEM results show that seed layer enhances the process to achieve vertical-aligned orientation of the TiO2 nanorods, which contribute to develop electron transport rate and could pay an important role inelectron transport layer in high-performance Perovskite solar cell.
关键词： seed layer,hydrothermal method,rutile TiO2 nanorods,Perovskite solar cell,electron transport layer
更新于2025-09-23 15:19:57
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Structural, morphological and 6 MeV energy electron dosimetric properties of Cu doped SnO<sub>2</sub> phosphor.
摘要： Cu doped SnO2 (SnO2:Cu) nano phosphor (NP) was successfully synthesized by one-step simple hydrothermal method and it was characterized by XRD (X-Ray Diffraction) for structural, FESEM (Field Emission Scanning Electron Microscopy) for morphological and EDS (Electron Dispersive Spectroscopy) for elemental analysis. NP was annealed at 700 °C for 2 hr and its crystallinity for tetragonal phase was confirmed through XRD. The crystallite size was ~10.39 nm for un-annealed and ~18.16 nm for annealed samples which has been calculated using Scherer equation. The particle size was estimated to be ~43 nm and the elemental composition of Sn, O, Cu was obtained by EDS. In addition, to study the dosimetric properties, the SnO2:Cu phosphors were irradiated with 6 MeV electron beam at fluences ranging from 10 x 10^11 e/cm^2 to 20 x 10^12 e/cm^2 which is equivalent to the 1.55 kGy to 31 kGy. The irradiated sample showed Thermoluminescence (TL) dosimetric glow peaks at 170 °C, 263 °C and 303 °C. SnO2:Cu NP was found to be sensitive enough for energetic electrons. Further, it has been noticed that the TL dose response found sensitive upto 10 x 10^12 e/cm^2 (15.50 kGy) with fading of 5.1 % for 2 months. Hence, SnO2:Cu can be used for the measurement of electron doses.
关键词： Hydrothermal Method,Electron Irradiation,Thermoluminescence,SnO2
更新于2025-09-19 17:15:36