ZnO Nanostructures Research Articles

Synthesis and characterization of Cu-Doped ZnO nanostructures for UV sensing application

In this work, Fabrication, and characterization of Cu-doped ZnO thin films deposited on porous silicon (PSi) substrates have been reported using electrochemical deposition (ECD) technique. The influence of Cu-doping concentrations on morphology, structure, and electrical characteristics of zinc oxide (ZnO) thin films were presented. X-ray diffraction analysis (XRD) has been used to characterize the lattice constants, average size, in-plane (along a-axis) and out of plane (along c-axis) strains for the Cu–ZnO crystals. The effects of Cu-doping concentration on crystal parameters were also investigated from the XRD analysis. The samples were used for UV-sensing applications. In addition, Cu-doped ZnO and pure ZnO metal–semiconductor-metal photodetector, with Cu as electrode contacts were successfully produced for ultraviolet (UV) detection. The I-V (current–voltage) characteristics were used to study the sensing enhancement. Finally, the UV photodetector based on Cu-doped ZnO films was successfully fabricated and shows a five times enhancement in the sensitivity to UV light compared to that of pure ZnO photodetector.

Photoluminescence of Erbium-Doped ZnO Nanostructures

The present work reviews the results of the photoluminescence study of erbium-doped ZnO nanostructures synthesized by physical and chemical methods. ZnO is a semiconductor compound composed of zinc and oxygen atoms. It possesses a wide bandgap (3.37 eV) and is optically and electrically active. When ZnO is synthesized in the form of nanostructures, such as nanoparticles, nanowires, nanorods, nanotubes, or nanosheets, it exhibits enhanced properties compared to its bulk counterpart due to quantum confinement effects and a high surface-to-volume ratio. By controlling different parameters in the growth processes of erbium-doped ZnO nanostructures, materials can be synthesized for different applications such as sensors, optoelectronics, and energy harvesting.

Synthesis and Characterization of Flower-Like Cobalt-Doped ZnO Nanostructures for Ammonia Sensing Applications

Abstract The present study uses the co-precipitation method to explore the synthesis of zinc oxide and cobalt-doped ZnO sensors, encompassing a range of cobalt concentrations from 1 to 4 wt.%. The synthesized samples undergo comprehensive analysis to evaluate their structural, morphological, optical, and gas-sensing properties. X-ray diffraction revealed a hexagonal Wurtzite structure, and the crystallite size decreased from 16.92 to 15.39 nm. Energy-dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy collectively affirmed the presence of cobalt. Scanning electron microscopy was used to analyze the morphological characteristics. The Tauc-plot was used to determine the optical bandgap via diffuse reflectance spectroscopy. As cobalt doping increased, the band gap increased from 3.18 to 3.23 eV. Further, atomic force microscopy and Brunauer-Emmett-Teller analysis were used to assess the surface topography and pore size distribution. The AFM measurements indicated roughness within 435-700 nm. The BET analysis revealed mesoporous properties, with surface area ranging between 18.657 to 21.962 m2/g. Subsequently, the gas-sensing capabilities of the Co-doped ZnO sensors were examined for various volatile organic compounds at room temperature. The sensor with 4% Cobalt doping exhibited a fast response and recovery time of 21 and 20 seconds for 2 ppm of NH3

Study of the antimicrobial activity of zinc oxide nanostructures mediated by two morphological structures of leaf extracts of Eucalyptus robusta Sm

The growing microbial resistance against antibiotics and the development of resistant strains has shifted the interests of many scientists to focus on metallic nanoparticle applications. Although several metal oxide nanoparticles have been synthesized using green route approach to measure their antimicrobial activity, there has been little or no literature on the use of Eucalyptus robusta Smith aqueous leaf extract mediated zinc oxide nanoparticles (ZnONPs). The study therefore examined the effect of two morphological nanostructures of Eucalyptus robusta Sm mediated ZnONPs and their antimicrobial and antifungal potential on some selected pathogens using disc diffusion method. The samples were characterized using Scanning and Transmission Electron Microscopy, Energy-Dispersive Spectroscopy and Fourier Transform Infrared Spectroscopy. From the results, the two ZnO samples were agglomerated with zinc oxide nanocrystalline structure sample calcined at 400 °C (ZnO NS400) been spherical in shape while zinc oxide nanocrystalline structure sample calcined at 60 °C (ZnO NS60) was rod-like. The sample calcined at higher temperature recorded the smallest particle size of 49.16 ± 1.6 nm as compared to the low temperature calcined sample of 51.04 ± 17.5 nm. It is obvious from the results that, ZnO NS400 exhibited better antibacterial and antifungal activity than ZnO NS60. Out of the different bacterial and fungal strains, ZnO NS400 sample showed an enhanced activity against S. aureus (17.2 ± 0.1 mm) bacterial strain and C. albicans (15.7 ± 0.1 mm) fungal strain at 50 mg/ml. Since this sample showed higher antimicrobial and antifungal activity, it may be explored for its applications in some fields including medicine, agriculture, and aquaculture industry in combating some of the pathogens that has been a worry to the sector. Notwithstanding, the study also provides valuable insights for future studies aiming to explore the antimicrobial potential of other plant extracts mediated zinc oxide nanostructures.

Green Synthesis and Characterization of Zinc Oxide Using Carica papaya Leaf Extract

AbstractEnvironmental methodologies are gaining recognition in this modern world. Environmental nanotechnology plays a major role in improving modern fields of environmental engineering and science. Metal oxide nanoparticles have exceptional properties due to their small size, including quantum confinement, surface‐to‐volume ratio, plasmon excitation, high biocompatibility, and surface modifiability. The biosynthesis of nanoparticles using fungi, bacteria, and plants through various biotechnological techniques is currently a new paradigm for environmental protection. Synthesis of nanoparticles through plant extract is good because it eliminates the dangers of toxic chemicals, it is environmentally friendly, simpler, and safer as the reaction time is reduced and it can also be increased in size for higher operation. The present study is based on the development of zinc oxide nanoparticles from papaya leaf extract where zinc nitrate is used as a precursor. The biosynthesized nanoparticles are characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, electron microscopy, energy‐dispersive X‐ray analysis, UV‐visible spectroscopy, and dynamic light scattering analysis. The crystalline phase determination of the zinc oxide nanoparticles is analyzed by X‐ray diffraction and the formation of polycrystalline zinc oxide nanoparticles is confirmed. FT‐IR spectrum reveals the main functional groups and chemical information in zinc oxide nanostructures. Morphological analysis is performed using SEM at different magnification levels. EDAX analysis shows the purity of the composite samples. Optical characterization is performed using a UV–vis spectrophotometer. DLS analysis shows that the nanoparticles formed have a relatively well‐defined dimension.

Carbon fabric coated with nanostructured zinc oxide layers for use in triboelectric self-powered touch sensors

An environmentally friendly, low-cost, and lightweight biocompatible textile triboelectric material was made by in situ coating carbon fabric (CF) with nanostructured zinc oxide (ZnO) layers using the automatic Successive Ionic Layer Adsorption and Reaction (SILAR) method. Depending on the deposition mode, we created triboelectric CF/ZnO textiles with multidirectionally intergrown short ZnO nanorods or with arrays of ZnO nanosheets. The Raman spectra confirmed the hexagonal wurtzite structure of both types of ZnO layers and the unique a-axis texture of the nanosheets. In the developed triboelectric CF/ZnO/PET/ITO sensors, the upper tribonegative part was made of a polyethylene terephthalate film coated with a thin layer of indium-tin oxide, and the lower tribopositive part was made of CF/ZnO textile. In tests with repeated hand tapping at low frequency 1.3–13 Hz and a force of ∼ 5 N (pressure of ∼ 33 kPa), the open-circuit voltage pulses were ∼ 15 V for short ZnO nanorods and ∼ 30 V for ZnO nanosheets, their duration did not exceed a few milliseconds. Due to the nanosheet morphology of the ZnO layer, the maximum touch-induced surface charge density for the corresponding triboelectric textile (0.7 µC/m2) was almost twice than for the CF/ZnO textile with intergrown ZnO short nanorods (0.4 µC/m2). The touch sensor with ZnO nanosheets showed an output voltage of 3.6 V, a current density of 1.47 µA/cm2, and a power density of 1.8 µW/cm2. It can be used as a dual-mode sensor due to ability to recognize the hardness of objects by analyzing the output current peaks.

Improved optoelectrical performance of nanostructured ZnO/porous silicon photovoltaic devices

This report introduced a novel technique for epitaxial bottom-up deposition of macroporous zinc oxide thin films on porous silicon (PSi) substrates. For achieving a higher surface-to-volume ratio and improving the photon trapping ability of the ZnO top layer, an optimized high-porosity PSi substrate was chosen as the template. Then, ZnO thin film was grown on the PSi substrate using the radio-frequency sputter-deposition method. The morphology of samples showed that the epitaxial layer followed the porous nature of the PSi substrate and generated a macroporous ZnO structure. The influence of post-sputtering thermal treatment at different temperatures on the structural and optical characteristics of synthesized macroporous ZnO nanostructures was studied. According to the planar surface morphologies, the average grain size of the sputtered ZnO layers heated at 300, 400, and 500 °C were 826, 1027, and 1195 nm, respectively. These results conform with the increased average crystallite size of ZnO nanostructures with higher annealing temperatures. The calculated crystallite size values were 4.14, 7.76, and 8.84 nm for the annealing temperatures of 300, 400, and 500 °C, respectively. The optical properties of the deposited thin film were improved due to the annealing process at higher temperatures. The highest light absorption coefficient was reported for the thin film annealed at 500 °C. Next, prepared macroporous n-ZnO/p-PSi samples were used to fabricate heterojunction solar cells, and their electrical properties were studied at room temperature. The optoelectrical results showed improved performance of the fabricated devices with higher annealing temperatures. The results showed an enhanced efficiency of 15.08 % for the optimized device with an annealing temperature of 500 °C, which is assigned to its increased surface and enhanced exciton generation. Moreover, this device showed lower series resistance of 4.74 Ω and higher shunt resistance of 2.98 KΩ compared to other devices with lower annealing temperatures.

CO gas sensing properties of Pd- and Al-doped zinc oxide nanotubes: a DFT study

Surface engineering and doping of zinc oxide (ZnO) nanostructures have been two feasible techniques for improving the gas-detecting capability of these nanostructures. However, the role of fundamental processes and factors that affect this improvement has not been fully understood. In this study, the adsorption of CO gas molecules on Pd- and Al-doped ZnO nanotubes is investigated using the first-principles calculations. The binding strength and charge transport as well as some other structural and electronic properties of these nanotubes are studied. The calculation results indicate the active interaction of CO gas molecules with Pd- and Al-doped ZnO nanotubes at high adsorption energies. The results provide a better atomistic insight and a more comprehensive explanation of the improvements in the electrical properties and sensing capabilities of Pd- and Al-doped ZnO.

Colloidal stability and dielectric behavior of eco-friendly synthesized zinc oxide nanostructures from Moringa seeds

This study centers on the environmentally benign synthesis of zinc oxide nanoparticles (ZnO NPs) derived from Zn (CH3COO)2·2H2O and Moringa seeds. The synthesized nanostructures underwent comprehensive characterization utilizing diverse analytical techniques, encompassing X-ray diffraction (XRD), UV–VIS spectroscopy, field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. XRD measurements coupled with W–H plot transformation unequivocally confirmed the formation of ZnO nanostructures, characterized by an average size of 24.9 nm. UV–VIS spectroscopy, complemented by Kubelka Munk curve analysis, elucidated the direct conduction and determined a bandgap of 3.265 eV. FESEM analysis revealed minimal particle aggregation, showcasing well-defined grain boundaries spanning sizes from 20.4 to 87.7 nm. XPS analysis substantiated the presence of Zn (2p), Zn (3p), Zn (3d), and O (1s). Raman spectroscopy identified E2H as the predominant mode, followed by E1(TO) and (E2H-E2L). ZnO thin films, fabricated via pulsed laser deposition (PLD) and deposited onto silicon (100) substrates, exhibited exemplary morphology and discernible topography, characterized by a normal grain size distribution. Zeta potential tests yielded a value of approximately (z\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathcalligra{z}$$\\end{document} ~ − 43.8 mV), indicative of the commendable stability of the colloidal suspension, likely attributable to low particle aggregation. Dielectric measurements conducted on sintered pellets at 900 °C unveiled elevated capacitance and dielectric constant at low frequencies across the temperature range of 289.935–310 K. These findings affirm the potential utility of environmentally synthesized ZnO for a spectrum of applications, including energy devices and nanofluids.

Droplet-Based Preparation of ZnO-nanostructure Array for Microfluidic Fluorescence Biodetection.

Nanostructure-enhanced biodetection is widely used for early diagnosis and treatment, which plays an essential role in improving the cure rates of cancer patients. ZnO nanostructure-based fluorescence immunoassay has been demonstrated to enable effective and sensitive detection of cancer biomarkers for their excellent biocompatibility, high electrical point, and unique fluorescence enhancement properties. Further optimization of such fluorescence detection technology is still in demand to meet the requirements of highly sensitive, multiplex detection, and user-friendly devices. Droplet microfluidics is a promising platform for high-throughput analysis of biological assays, and they have been intensively used in analytical chemistry and synthesis of nanoparticles. Here, we propose a simple droplet chip, where a static droplet array was successfully obtained for in situ growth of ZnO nanostructures with varied diameters by changing the entire growth time and replenishment interval. This device provides a novel and alternative approach for patterned growth of ZnO nanostructures and understanding the growth condition of ZnO nanostructures in static droplet, which offers some guidance toward the design of multiple fluorescence amplification platforms potentially for biosensing. As a demonstration, we used the patterned grown ZnO nanostructures for multiple detection of cancer biomarkers, achieving a low limit of detection as low as 138 fg/mL in the human α-fetoprotein assay and 218 fg/mL in the carcinoembryonic antigen assay with a large dynamic range of 8 orders. These results suggest that such multifunctional microfluidic devices may be useful tools for efficient fluorescence diagnostic assays.

The physical properties and photocatalytic activities of green synthesized ZnO nanostructures using different ginger extract concentrations

The green synthesis method which is aligned with the sustainable development goals (SDGs) theory, is proposed to synthesize ZnO nanoparticles using ginger extract to treat the acidic wastewater and acidic factory effluent as a current challenge and the effects of the concentration of extracts on the synthesized ZnO nanostructures are investigated. The results declare that the single-phase hexagonal ZnO is formed using ginger extract concentration of less than 25 mL and the crystallite size of green synthesized ZnO NPs increased with increasing the concentration of ginger extract. Also, the significant effects of ginger extract concentration on the morphology of nanoparticles (nanocone, nanoflakes, and flower-like) and the particle size are demonstrated. The low concentration of ginger extract leads to the formation of the ZnO nanoflakes, while the flower-like structure is gradually completed by increasing the concentration of the ginger extract. Furthermore, significant changes in the specific surface area (SSA) of the samples are observed (in the range of 6.1–27.7 m2/g) by the variation of ginger extract concentration and the best SSA is related to using 10 mL ginger extract. Also, the strong effect of using ginger extract on the reflectance spectra of the green synthesized ZnO NPs, especially in the UV region is proved. The indirect (direct) band gap energies of the ZnO samples are obtained in the range of 3.09–3.20 eV (3.32–3.38 eV). Furthermore, the photocatalytic activities of the samples for the degradation of methylene blue indicate the impressive effect of ginger extract concentration on the degradation efficiency of ZnO nanoparticles and it reaches up to 44% and 83% for ZnO NPs prepared using 5 mL ginger extract in a pH of 4.3 and 5.6, respectively. This study provided new insights into the fabrication and practical application of high-performance ZnO photocatalysts synthesized using ginger extract in degrading organic pollutants in an acidic solution.

Enhanced sunlight-driven photocatalysis owing to synergetic effect of gold nanoparticles-incorporated ZnO/rGO ternary heterostructures

The combination of gold nanoparticles (Au NPs) incorporated ZnO/rGO heterostructures is unique for sunlight-driven photocatalysis (SPC). Here, hydrothermally synthesized pristine ZnO nanostructures (NSs), ZnO/rGO binary nanocomposites (BNCs) and ZnO/rGO/Au ternary nanocomposites (TNCs) of bandgap (Eg) values 3.56 eV, 3.37 eV and 3.17 eV, respectively are reported. These NSs are analyzed optically, structurally and morphologically via UV–Vis absorption spectroscopy, X-ray diffraction and SEM techniques, respectively. The SPC of methylene blue (MB) organic dye was considered using all three samples. The slow charge transfer over grain boundaries of ZnO results in the prohibition of photogenerated electron-hole pairs, exhibiting low photodegradation efficiency (87%). However, in BNCs the creation of alternative pathway of the carriers due to low work function level of rGO as compared to ZnO enhances the charge separation with an increased photocatalytic efficiency (92%). In contrast, TNCs show rather fast photodegradation efficiency (96%) as the photoexcited electrons on Au NPs surface migrate to the CB of ZnO because of the SPR stimulation of Au. These electrons easily shift to the conductive rGO layers and react with oxygen species (O2) producing superoxide radicals (•O2–). Thus, TNCs sample has appeared to be auspicious candidate for the photodegradation of organic pollutants in untreated water.

Efficient synthesis of 3D ZnO nanostructures on ITO surfaces for enhanced photoelectrochemical water splitting

New photoactive materials with uniform and well-defined morphologies were developed for efficient and sustainable photoelectrochemical (PEC) water splitting and hydrogen production. The investigation is focused on hydrothermal deposition of zinc oxide (ZnO) onto indium tin oxide (ITO) conductive surfaces and optimization of hydrothermal temperature for growing uniform sized 3D ZnO morphologies. Fine-tuning of hydrothermal temperature enhanced the scalability, efficiency, and performance of ZnO-decorated ITO electrodes used in PEC water splitting. Under UV light irradiation and using eco-friendly low-cost hydrothermal process in the presence of stable ZnO offered uniform 3D ZnO, which exhibited a high photocurrent of 0.6 mA/cm2 having stability up to 5 h under light-on and light-off conditions. The impact of hydrothermal temperature on the morphological properties of the deposited ZnO and its subsequent performance in PEC water splitting was investigated. The work contributes to advancement of scalable and efficient fabrication technique for developing energy converting photoactive materials.

A facile electrochemical cortisol sensing based on zinc oxide nanostructures for monitoring stress and recovery in high-performance athletes

This work created a simple electrochemical cortisol sensing method based on ZnO nanostructures to track high-performance athletes' stress levels and recuperation times. ZnO nanorods (ZnO NRs) were deposited on the surface of a glassy carbon electrode (ZnO/GCE) using an electrodeposition technique. Subsequently, 3-aminopropyltriethoxysilane (APTES) was applied to the electrode surface in order to improve cortisol antibody (C-M ab) immobilization and stability (C-M ab/APTES/ZnO/GCE). Successful immobilization of C-M ab on APTES/ZnO/GCE and electrodeposition of ZnO NRs on GCE were confirmed by structural investigations conducted using XRD, FT-IR, and FE-SEM. Cortisol was detected using an electrochemical immunosensor (C-M ab/APTES/ZnO/GCE) by monitoring the change in DPV and CV currents following cortisol binding to C-M ab. According to electrochemical experiments, the immunosensor exhibited a steady, selective, and sensitive response when it detected cortisol at concentrations between 10−6 nM and 106 nM, with a detection limit of 2 × 10−4 nM. It was assessed if the C-M ab/APTES/ZnO/GCE combination could identify cortisol in human serum. The samples' relative standard deviation (RSD) values range from 3.63% to 4.30%, and their recovery rates range from 90.00% to 98.50%, according to the analytical study. These findings imply that the C-M ab/APTES/ZnO/GCE offers accurate evaluations for cortisol detection in human serum samples.

Structural investigations of ZnO nanostructure

Undoped and Mn-doped ZnO samples with different percentages of Mn content (1, 5 and 10 at%) were synthesized by a dip coating sol–gel method. We have studied the structural, chemical and optical properties of the samples by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible spectroscopy. The XRD spectra show that all the samples are hexagonal wurtzite structures. We note that doping favors c-axis orientation along (002) planes. Up to 5 at% of Mn doping level, the c- axis lattice parameter shifts towards higher values with the increase of manganese content in the films. The expansion of the lattice constant of ZnO–Mn indicates that Mn is really doped into the ZnO. The SEM investigations of all samples revealed that the crystallites are of nanometer size. The sur- face quality of the ZnO–Mn film increases with Mn doping but no significant change of the grain size is observed from SEM images. The transmittance spectra show that the trans parency of all the samples is greater than 85 %. We note, also, that a small doping (1 %) lowered the refractive index while the thickness of the layers and the gap increase. However, on raising the proportion of Mn beyond 5 %, practically the same values of index and gap as pure ZnO are found.

Investigation on bare ZnO nanotubes and nanosheet as electrode materials for potassium-ion batteries: A DFT search

Within this work, the possibility of using (5,0), (6,0), (7,0), (8,0), and (9,0) zigzag ZnO nano-tubes and a ZnO nano-sheet (ZnONS) was investigated in potassium-ion batteries (KIBs) through the B3LYP-gCP-D3/6-31G* scheme. The cell voltage, ion diffusion coefficient, the maximum energy barrier for the migration of K+ and the adhesion energies of K+ and K of (5,0) nano-tube were 0.93 V, 5.31 × 10−8 cm2/s, –33.4 kcal/mol, respectively. The results showed that the impact of the dispersion term (D3) on the K and K+ adhesion energies was more than that of the gCP (basis set superposition error). A reduction in the curvature of the ZnONS dramatically weakened the interaction of the K atom, whereas it had a slight impact on the interaction of K+. Therefore, a decrease in the curvature of the ZnONS increased the cell voltage to 1.21 V. We can use ZnO nano-structures as a promising anode for KIBs.

Synthesis of Bitter gourd-shaped Cu-doped ZnO nanostructures and their investigation for the detection of NO2 gas at low concentrations

Nitrogen dioxide (NO2) exposure can have several adverse health impacts on people, especially the respiratory system. Low selectivity, a lack of long-term stability, and structural and morphological optimization are some challenges associated with using ZnO for NO2 gas sensing. Therefore, we intended copper (Cu) doping in ZnO to alter its shape and gas-sensing characteristics. This study explores the synthesis, properties, and gas-sensing capabilities of bitter gourd-shaped Cu-doped zinc oxide (ZnO) nanostructures for the detection of nitrogen dioxide (NO2). A facile hydrothermal synthesis method was employed to synthesize bitter gourd-shaped Cu-doped ZnO nanostructures and comprehensively characterized by several techniques. Comprehensive characterizations of our produced Cu-doped ZnO nanomaterial demonstrated by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS), and different energy spectrum. The material was annealed at 400 °C in a controlled dry air environment to improve its suitability for gas sensor applications. A series of temperature-ranging experiments were conducted to get gas-sensing readings from 25 °C to 300 °C. The resulting sensor, founded upon the distinctive morphology of Cu-doped ZnO structures reminiscent of the intricate shape of bitter gourd, unveiled good selectivity with a pronounced affinity for detecting NO2 gas. Notably, the zenith of its performance was attained at an operating temperature of 200 °C, where its selectivity and sensitivity were most pronounced. Even at a low concentration of 1 ppm, the sensors displayed a maximum response of 3.7, highlighting their high sensitivity. The sensors demonstrated excellent reproducibility, selectivity, and a low detection limit. These findings position bitter gourd-shaped Cu-doped ZnO nanostructures as promising candidates for NO2 sensing applications across diverse environments.

Enhancing the durability of reversible wettability on larch wood surfaces through optimized pretreatment methods

The development of superhydrophobic layers on wood is attracting plenty of scientific attention lately in the field of functional wood modification. However, the ability to resist mechanical wear is essential to improve the durability of the functional surface through simple treatment. Hot water, acid, and alkali were initially used to pre-treat larch wood samples, followed by a hydrothermal procedure to deposit zinc oxide (ZnO) nanostructures on the surface of the pretreated wood. Wood that has been pure water hydrothermally processed has a more distinctive ZnO structure with a compact arrangement and rod structure. After pretreatment, the surface contact angle of ZnO wood was greater than 150°, showing excellent superhydrophobic property, while the surface of directly loaded ZnO wood did not. Most importantly, in the test of wear resistance, hot water pretreated ZnO wood showed the optimized performance. The densely packed ZnO nanorods generated by hydrothermal pretreatment exhibit a more stable bond with the wood surface, thereby enhancing the mechanical stability of the wood to some extent both in the sandpaper wear and the tape tearing test. The superhydrophobic modified wood surface also had outstanding self-cleaning talents, which can also easily switch between light and heat caused a reversible shift in the surface wettability. This study offers insight into wood functionalization and addresses the endurance of surface changes on biomass materials.

Novel N3-Schiff base and its zinc halide/pseudohalide complexes: Antimicrobial, antioxidant, cytotoxicity and burn wound healing activities

A new N3-tridentate Schiff base ligand(L) was synthesized by condensation reaction of 2-methoxycinnamaldehyde and diethylenetriamine. Thereafter some new zinc complexes formulated as [ZnLX2] (X is halide or pseudo-halide) were prepared using this chelating ligand. The suggested structures of these compounds were identified by melting point and molar conductivity measuring, UV–Visible, FT/IR, 1H and 13C NMR and MASS spectral analyses. Moreover, the thermal behaviors of the ligand and zinc complexes were investigated under N2 atmosphere and at a heating rate of 20 °C/min. Zinc bromide and chloride complexes were synthesized in nanostructured sizes by sonochemical method and used as precursor to prepare nanostructured ZnO approved by SEM, EDX and XRD analyzes. Furthermore antibacterial, antifungal and antioxidant properties were evaluated by well diffusion, ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) methods respectively. Cytotoxicity properties of the ligand and zinc complexes were assessed against prostate cancerous cell lines (PC3) as compared with HUVEC normal cells. The morphology of PC3 cancer cells treated by the ligand and some zinc complexes were also visualized by images. Eventually, burn wound healing activities of the ligand and zinc chloride complex were examined for healing of the second degree burns in the rats in a period of 20 days.

Investigation of the structural and electrical behaviour of Mn-substituted ZnO

ABSTRACT Zinc oxide (ZnO) nanostructures with the general formula Zn1-xMnxO were made using a simple and affordable wet chemical coprecipitation method. X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), and scanning electron microscopy (SEM) were used to examine the structure and morphology of the produced samples. All of the prepared oxides were found to have a single crystalline phase that is ZnO-specific and has a wurtzite structure. It is found that DC conductivity rises with temperature and a steady drop in both AC and DC conductivity with Mn concentration is seen, which might be attributed to the creation of a grain boundary defect barrier. Complex impedance analysis is used to distinguish the grain and grain boundary contribution to the system. The parameters dielectric constant (k) and dielectric loss (tan δ) decreased as the frequency increased, and as the Mn concentration increased. With increasing temperatures, the dielectric constant and loss both increased.