Nanoscale ZnO is one of the best choices for ultraviolet (UV) protection, not only because of its antimicrobial properties but also due to its potential application for UV preservation. However, the ...behavior of nanostructured thin ZnO films and long-term effects of UV-radiation exposure have not been studied yet. In this study, we investigated the UV-protection ability of sol gel-derived thin ZnO films after different exposure times. Scanning electron microscopy, atomic force microscopy, and UV-visible optical spectroscopy were carried out to study the structure and optical properties of the ZnO films as a function of the UV-irradiation time. The results obtained showed that the prepared thin ZnO films were somewhat transparent under the visible wavelength region and protective against UV radiation. The UV-protection factor was 50+ for the prepared samples, indicating that they were excellent UV protectors. The deposited thin ZnO films demonstrated promising antibacterial potential and significant light absorbance in the UV range. The experimental results suggest that the synthesized samples have potential for applications in the health care field.
Plants are one of the best sources to obtain a variety of natural surfactants in the field of green synthesizing material. Sambucus ebulus, which has unique natural properties, has been considered a ...promising material in traditional Asian medicine. In this context, zinc oxide nanoparticles (ZnO NPs) were prepared using S. ebulus leaf extract, and their physicochemical properties were investigated. X-ray diffraction (XRD) results revealed that the prepared ZnO NPs are highly crystalline, having a wurtzite crystal structure. The average crystallite size of prepared NPs was around 17 nm. Green synthesized NPs showed excellent absorption in the UV region as well as strong yellow-orange emission at room temperature. Prepared nanoparticles exhibited good antibacterial activity against various organisms and a passable photocatalytic degradation of methylene blue dye pollutants. The obtained results demonstrated that the biosynthesized ZnO NPs reveal interesting characteristics for various potential applications in the future.
L-α-alanine (LαA) is a non-essential α-amino acid in the human body. Free radicals formations in LαA induced by solid-state radiation have been the subject of investigations by electron paramagnetic ...resonance (EPR) spectroscopy. The Density Functional Theory (DFT) formalism has been used to calculate the EPR parameters of the radiation-induced radicals in the solid-state LαA in this article. Here, the effects of various factors such as the kind of hydrogen bonding (short and long-range) and the temperature have considered to calculate the EPR parameters. An atomic static cluster model has been used to evaluate the short-range hydrogen bonding effects, and Molecular Dynamic (MD) cluster model has been used simultaneously to study the influence of the short-range hydrogen bonding and temperature. A static periodic technique has been used to consider hydrogen bonds (short and long-range) effect. Finally, the MD periodic calculations have been used simultaneously to study the influence of the hydrogen bonds and temperature. These MD periodic calculations are more consistent with experiments than static periodic calculations and clusters. The EPR spectrums of LαA powder and crystal have been simulated and compared with the experimental EPR spectrums. The results show that they are in good agreement with the experimental results.
Integration of chip-scale quantum technology was the main aim of this study. First, the recent progress on silicon-based photonic integrated circuits is surveyed, and then it is shown that silicon ...integrated quantum photonics can be considered a compelling platform for the future of quantum technologies. Among subsections of quantum technology, quantum emitters were selected as the object, and different quantum emitters such as quantum dots, 2D materials, and carbon nanotubes are introduced. Later on, the most recent progress is highlighted to provide an extensive overview of the development of chip-scale quantum emitters. It seems that the next step towards the practical application of quantum emitters is to generate position-controlled quantum light sources. Among developed processes, it can be recognized that droplet–epitaxial QD growth has a promising future for the preparation of chip-scale quantum emitters.
Due to their versatility, thin metal films are being used in many modern technologies, such as optoelectronics, microelectronics, catalysis, energy conversion and storage, sensors, actuators, and ...food packaging ...
In this paper, a solid‐state reaction route was developed to synthesize SrB6O10 crystalline powders. Regarding the last preparation methods, a short process time of synthesis was achieved that has ...not reported before. The prepared sample was characterized using various methods, such as X‐ray diffraction, Raman spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and diffuse reflection spectroscopy. The obtained results proved that the prepared sample at temperature 840°C with 2.5 h duration consists of SrB6O10 crystalline powders with 4.96 eV bandgap.
Ag/PVP nanocomposites were prepared by a chemical reduction process. Then, a drop-casting method was employed to deposit the Ag/PVP nanocomposite thin film on the glass substrate. To study the ...optical and structural properties of the prepared sample, different characterization methods including UV–Vis absorption spectroscopy, scanning electron microscopy, XPS, and Raman spectroscopy were employed. The optical nonlinearity of the prepared thin films was evaluated by the Z-scan technique using a He–Ne laser beam (632 nm). Results showed that the nonlinear refraction index (n
2
~ 10
−6
cm
2
/w) and nonlinear absorption coefficient (β ~ 10
−1
cm/w) of the prepared Ag/PVP nanocomposite thin film are higher than the previously reported values. A weak thermal optical nonlinearity was also observed and the nonlinear response dominantly resulted from the electronic origin.
The optical absorption and fluorescence of Rhodamine B dye solution with different dye concentrations, from 0.1 to 40 µM, in the presence of gold nanorods were studied. Colloidal gold nanorods were ...characterized by UV-Visible spectrophotometry and Transmission Electron Microscopy. Rhodamine B dye absorbance with and without gold nanorods was shown to be approximately constant, due to the dominance of the absorbance term of longitudinal surface plasmon resonance of gold nanorods. The fluorescence peak of dye-nanorods mixture with respect to that of pure dye was blue shifted. By increasing the dye concentrations, the energy transfer efficiency between the dye-nanorod pair was increased and, as a result, the fluorescence quantum yield was decreased. The results of the spectral overlapping of the absorption and the fluorescence spectra of RhB dye solution, with and without gold nanorods, matched well with the calculated energy transfer efficiency.
Nano-bioimaging is a real-time observation method for the study of biological processes in subcellular structures and entire cells. This technique aims to interfere as little as possible with life ...processes using nanoscale materials and probes. In this method, nanoscale photon source is often used for imaging, and 3D structure of the observed specimen is studied in detail without physical interference. Over the last decade, further boost in bioimaging has led to increase the nano-bioimaging impact that includes many improvements in the data analysis method, image processing, and molecular imaging technology. However, to increase the usage of nano-bioimaging, several developments in the field of diagnosis accuracy, photobleaching prevention, and controlling of the fluorescence resonance energy transfer (FRET) must be achieved. The purpose of this book is to provide a perspective on the current status of nano-bioimaging technologies.
In this research, highly transparent and conducting hafnium doped zinc oxide (HZO) thin films were prepared by the simple sol-gel dip coating technique. Controlled doping process and synthesis method ...were used to improve the optical and electrical properties of HZO thin films. The structures, optical and electrical properties of the samples were characterized by XRD, XPS, FESEM, TEM, EDS, UV-Visible, and PL spectroscopy. Hall-effect measurement was performed to study the electrical properties of the HZO thin films. For the first time, HZO thin film with very low resistivity (4.2 × 10−3 .cm) was prepared. At room temperature, strong green emission peak was observed for HZO thin films. Obtained results in this study are better than reported results before. This improvement may be related to the synthesis method of nanoparticles. HZO thin films may be an affordable candidate for optoelectronic device applications and a new replacement for ITO thin film.
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