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Sol–Gel Spin-Coating Followed by Solvothermal Synthesis of Nanorods-Based ZnO Thin Films: Microstructural, Optical, and Gas Sensing Properties
摘要： Zinc oxide thin films with nanorod morphology were investigated for microstructural and optical properties as well as their performance as a liquid petroleum gas sensing material. A two-step synthesis procedure consisting of sol–gel spin-coating and solvothermal methods was employed where several factors such as rational utilization of metal precursors, solvent, stabilizing, and structure directing agents, a repetitive drying-coating process, as well as post-thermal annealing were found influential to obtain qualified nanorods and a final homogeneous thin film. Compositional and optical investigations were pursued to characterize features, namely morphology, poly crystallinity, porous structure, nanocrystallite size, lattice oriented growth, textural atomic ratio, lattice purity and transparency, phonon and exciton transitions, as well as the formed structural defects via field-emission scanning electron microscopy, x-ray diffraction, energy-dispersive x-ray, UV–Vis spectroscopy, Raman, and photoluminescence techniques. The as-prepared thin film was then used as an active LPG sensing material via a home-made gas sensor where the control sensing parameters were chamber testing temperature and gas concentration. Results showed a quantitative response of 92.7% as sensor sensitivity at an operation temperature of 250°C and a LPG concentration of 800 ppm in addition to fast response and recovery times of 44.1 s and 218.7 s, respectively.
关键词： Zinc oxide nanorods,thin film,optical characteristics,gas sensing,microstructural properties,liquid petroleum gas
更新于2025-09-23 15:23:52
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Shape-dependant photocatalytic and antimicrobial activity of ZnO nanostructures when conjugated to graphene quantum dots
摘要： To reduce the bandgap and e-/h+ pairs recombination, zinc oxide nanoflakes (ZnO-NFs) and zinc oxide nanorods (ZnO-NRs) were covalently linked to graphene oxide quantum dots (GQDs). Photocatalytic and antimicrobial activity of ZnO nanohybrids (ZnO-NFs@GQDs and ZnO-NRs@GQDs) were investigated. The formation of the distinct ZnO nanoflakes and ZnO nanorods shaped nanoparticles were evidenced by SEM. The bandgap decreased from 2.98 to 2.61 eV and 3.00 to 2.79 eV for ZnO-NFs@GQDs and ZnO-NRs@GQDs, respectively. Photoluminescence (PL) data showed a similar trend where a larger decrease was obtained for ZnO-NFs@GQDs. Photolysis ruled out adsorption mechanism for the removal of dye. Optical data and PL measurements supported photocatalytic findings that ZnO-NFs@GQDs performed better (80%) than ZnO-NRs@GQDs (18%). ZnO-NRs@GQDs however, showed greater bacterial inhibition when tested against E. coli, P. aeruginosa, B. cereus and S. aureus. The antimicrobial efficiency followed the order: ZnO-NFs < ZnO-NFs@GQDs < ZnO-NRs < ZnO-NRs@GQDs with greater efficiency being against S. aureus. Liquid photocatalysts zinc nanoparticles can thus be used to remove dyes and inhibit bacterial growth in aqueous solution.
关键词： Zinc oxide nanorods,zinc oxide nanoflakes,antimicrobial activity,photocatalysis,graphene quantum dots
更新于2025-09-23 15:19:57
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Optical fiber coated Zinc Oxide (ZnO) nanorods decorated with Palladium (Pd) for hydrogen sensing
摘要： A novel hydrogen (H2) sensor was developed using acid-etched optical fiber coated with zinc oxide (ZnO) nanorods. The sensing performance was done by comparing the acid-etched fiber coated with ZnO nanorods with and without decorated Palladium (Pd). The conventional optical single-mode fiber (SMF) with a diameter of 125 μm has been modified as a transducing platform by etching it to 11 μm diameter using hydrofluoric acid (HF) to enhance the evanescent field of the light propagates in the fiber core. The etched fiber was coated with ZnO nanorods via hydrothermal process by using seeding and growth solution method. The sensing layer was characterized through Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX) and X-Ray Diffraction (XRD) to verify the properties of ZnO. Catalyst Palladium (Pd) was sputtered onto the ZnO nanorods to improve H2 detection. The developed sensor operating temperature was found to be 150 °C that produces 6.36 dBm increase in response towards the 1% concentration of H2 in synthetic air. It was then tested with different concentration of H2. The sensor decorated with Pd has better performance in sensing compared to non-decorated Pd based on the output power versus time. The sensor best response and recovery times is 6 and 5 min respectively, for acid-etched optical fiber coated with ZnO nanorods decorated with Pd for 0.75% of H2 concentrations at 150 °C. The results indicate the optical fiber sensor might improve the performance towards H2 as oppose to the conventional electrical sensor.
关键词： Zinc oxide nanorods,Etching optical fiber,Hydrothermal method,Light-intensity response,Hydrogen sensor,Fiber optic sensor
更新于2025-09-19 17:13:59
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Fabrication of arrangement-controlled and vertically grown ZnO nanorods by metal nanotransfer printing
摘要： Vertically aligned ZnO nanorods have been widely investigated for use in piezoelectric generators, photovoltaic devices, nanotemplates, photoelectrochemical applications, etc. In addition to vertical alignment, intentional arrangement of ZnO nanorods according to a careful design can enhance the device performance. In this work, we used metal nanotransfer printing to fabricate arrangement-controlled and vertically grown ZnO nanorods on both hard and flexible substrates. Highly vertical growth and periodical arrangement of the ZnO nanorods were confirmed by microscope images. Their crystallinity and photoluminescence characteristics were also investigated. Transmission spectra of the substrates show the enhancement of optical transmission after the nanorod growth. We believe that this fabrication technique lends itself to simple fabrication of arrangement-controlled and vertically grown one-dimensional nanostructures on both hard and flexible substrates for application in solar cells, water splitting, metamaterials, etc.
关键词： Zinc oxide nanorods,Flexible substrate,Intentional arrangement,Hard substrate,Nanotransfer printing
更新于2025-09-12 10:27:22
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Growth of Zinc Oxide Nanorods with the Thickness of Less than or Equal to 1? <i>μ</i> m through Zinc Acetate or Zinc Nitrate for Perovskite Solar Cell Applications
摘要： Arrays of zinc oxide (ZnO) nanorod (NR) were fabricated in a vertical axis direction through the two-step method of seed layer’s deposition and growth of the NR. The seed layer was applied by spin coating with a three-time repetition (n) and rotational speed (v) at 3000 rpm. After the seed layer had grown, ZnO NRs were grown with a growth solution made by combining one zinc source with one hydroxide source. There were two di?erent zinc sources, i.e., zinc acetate dehydrate and zinc nitrate hexahydrate and, for comparison, zinc acetate (ZA) and zinc nitrate (ZN) were each combined with the same hydroxide source, hexamethylene-tetramine (HMT). Later, the growth solutions were processed by the chemical bath deposition (CBD) method using a waterbath machine. The CBD method was started at room temperature until it reached the designated temperature at 85°C. At that point, the growth time was calculated from the zero-minute condition. It was found that ZnO NRs had already grown at a thickness of about 100 nm for both ZA and ZN sources. The growth time varied at 15, 60, 90, and 120 minutes after the zero-minute point. By using two separate and independent zinc sources while growing ZnO NRs at various growth periods, several ZnO NRs’ thicknesses were controlled. According to a paper by Lee et al., the lower thickness of ZnO NRs boosted the charge transfer properties of perovskite solar cells (PSCs) because the series resistance between ZnO/perovskite interfaces was lessened. Scanning electron microscopy (SEM) images were observed to analyze the morphological shape of the ZnO NRs. X-ray di?raction (XRD) pro?les were characterized to obtain the data for ZnO NR crystallinity. Full width at half maximum (FWHM) analysis was performed at the (002) ZnO peak to calculate the crystal size of the peak. From the results, the smallest crystallite sizes for ZnO NRs grown from ZA and ZN sources were 10.70 nm and 19.29 nm, respectively, which would be the most suitable condition for PSC application.
关键词： zinc oxide nanorods,perovskite solar cells,chemical bath deposition,spin coating,seed layer
更新于2025-09-11 14:15:04
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Zinc Oxide Nanorods Wrapped with Ion-Imprinted Polypyrrole Polymer for Picomolar Selective and Electrochemical Detection of Mercury II Ions
摘要： This study concerns the design of an ion-imprinted polymer (IIP) for the selective detection of mercury II ions. Compared to other electrochemical studies, the originality of this work lies to the fact that the IIP was electropolymerized on ZnO nanorods, which were themselves grown on gold/diazonium modified substrates. This strategy of diazonium salt and ZnO nanorods permits to increase considerably the specific surface and thus to improve the sensor’s performances. The limit of detection (LOD) of the designed sensor was of order of 1 pM, the lowest value ever reported in literature.
关键词： mercury,electrochemical detection,ionic imprinted polymer,zinc oxide nanorods
更新于2025-09-04 15:30:14