Preparation and Characterization of (Al, Fe) Codoped ZnO Films Prepared by Sol–Gel

In this research, Al-doped and (Al, Fe) codoped ZnO films were prepared on glass substrate by the sol–gel method. The surface morphology, structure, and optical property were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Ultraviolet-Visible-Near-infrared (UV-Vis-NIR) spectroscopy. The film surface morphologies all exhibited granular characteristics. With the Fe doping concentration increasing, the codoped films had smaller grain size and tended to be smoother. XRD analysis revealed that all films had a hexagonal wurtzite structure. The codoping can contribute to more Al and Fe ions entering the ZnO crystal structure, but result in the crystalline degree of the films decreasing. XPS results showed that the Al and Fe irons in the films exist in the form of trivalent. Moreover, the doped films had higher transmission, especially for codoped (Fe:Al = 3) film, but their absorption edge shifted to the short-wavelength direction.

Magnetic ZnO Crystal Nanoparticle Growth on Reduced Graphene Oxide for Enhanced Photocatalytic Performance under Visible Light Irradiation

Magnetite zinc oxide (MZ) (Fe3O4/ZnO) with different ratios of reduced graphene oxide (rGO) was synthesized using the solid-state method. The structural and optical properties of the nanocomposites were analyzed using transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis/DRS), and photoluminescence (PL) spectrophotometry. In particular, the analyses show higher photocatalytic movement for crystalline nanocomposite (MZG) than MZ and ZnO nanoparticles. The photocatalytic degradation of methylene blue (MB) with crystalline ZnO for 1.5 h under visible light was 12%. By contrast, the photocatalytic activity for MZG was more than 98.5%. The superior photocatalytic activity of the crystalline nanocomposite was detected to be due to the synergistic effect between magnetite and zinc oxide in the presence of reduced graphene oxide. Moreover, the fabricated nanocomposite had high electron–hole stability. The crystalline nanocomposite was stable when the material was used several times.

Photoluminescence Properties and Electrochemical Performance of Fe:ZnO Nanoparticles in Li-Ion Batteries

The pure and Fe doped ZnO nanoparticles with varying iron mole percentages of 3%, 4.5% and 6% were synthesized by using co-precipitation. Structural and morphological properties as well as electrochemical properties, serving as anode in Li-ion batteries, were studied. All samples have hexzagonal wurtzite ZnO crystal structure and a slightly shift from x-ray difraction patterns of Fe:ZnO samples have shown that Fe3+ ions substituted by Zn2+ ions. As the percentage of Fe mol increases from 3–4.5%, the size of the particles decreases, and as the percentage of Fe mol decreases from 4.5–6%, it also increases. The emission bands originated due to energy levels generated by ZnO intrinsic defects in all samples. In half cell configuration, 3% Fe:ZnO and 6 % Fe:ZnO anode exhibit rapid capacity fading. ZnO anode with Fe mol percentage of 4.5 % results a substantially enhances sepecific capacity during 50 cycle.

Influence of Calcination Temperature on Crystal Growth and Optical Characteristics of Eu3+ Doped ZnO/Zn2SiO4 Composites Fabricated via Simple Thermal Treatment Method

This research paper proposes the usage of a simple thermal treatment method to synthesis the pure and Eu3+ doped ZnO/Zn2SiO4 based composites which undergo calcination process at different temperatures. The effect of calcination temperatures on the structural, morphological, and optical properties of ZnO/Zn2SiO4 based composites have been studied. The XRD analysis shows the existence of two major phases which are ZnO and Zn2SiO4 crystals and supported by the finding in the FT-IR. The FESEM micrograph further confirms the existence of both ZnO and Zn2SiO4 crystal phases, with progress in the calcination temperature around 700–800 °C which affects the existence of the necking-like shape particle. Absorption humps discovered through UV-Vis spectroscopy revealed that at the higher calcination temperature effects for higher absorption intensity while absorption bands can be seen at below 400 nm with dropping of absorption bands at 370–375 nm. Two types of band gap can be seen from the energy band gap analysis which occurs from ZnO crystal and Zn2SiO4 crystal progress. It is also discovered that for Eu3+ doped ZnO/Zn2SiO4 composites, the Zn2SiO4 crystal (5.11–4.71 eV) has a higher band gap compared to the ZnO crystal (3.271–4.07 eV). While, for the photoluminescence study, excited at 400 nm, the emission spectra of Eu3+ doped ZnO/Zn2SiO4 revealed higher emission intensity compared to pure ZnO/Zn2SiO4 with higher calcination temperature exhibit higher emission intensity at 615 nm with 700 °C being the optimum temperature. The emission spectra also show that the calcination temperature contributed to enhancing the emission intensity.

Особенности фотолюминесценции в кристаллах ниобата лития, легированных цинком в широком диапазоне концентраций

The concentration changes in the photoluminescence spectra of LiNbO3 : Zn crystals (0.004 ÷ 6.5 mol.% ZnO) were studied. It was found that with the increase of zinc concentration from 0.004 to 1.42 mol.% ZnO, the intensity decrease of luminescence bands caused by VLI, NbNb, and NbNb−NbLi defects was observed. As the crystal composition approached the second concentration threshold (≈ 7.0 mol.% ZnO), the luminescent halo shifted by ≈ 0.41 eV to the high-energy region of the spectrum and the intensity of the luminescence centers increased at 2.66 and 2.26 eV. It was caused by the appearance of ZnLi point defects. It was shown that in the LiNbO3 : Zn(4.69 mol.% ZnO) crystal obtained by homogeneous doping technology, there is a greater number of luminescence centers of different origin than in congruent and zinc-doped crystals obtained by direct melt doping technology. In the LiNbO3 : Zn crystal (4.52 mol.% ZnO), the luminescence of the main defects (VLi, NbNb, ZnLi) was quenched by increasing the fraction of nonradiative transitions relative to other LiNbO3 : Zn crystals in the concentration range [ZnO] = 4.46 ÷ 6.50 mol.%.

Growth manner of rod-shaped ZnO crystals at low temperature without any seed/buffer layer on a polyimide film

Recently, we fabricated a rod-shaped ZnO crystal layer directly on a polyimide substrate without any intermediate layer. In this study, we aimed to understand its fabrication mechanism.

Biosynthesis of Triangular-Shape ZnO Nanoparticles Using Tecoma Stans and Its Antimicrobial Activity

<div>The present work reports the first green synthesis of zinc oxide nanoparticles (ZnO-NPs) using Tecoma stans leaf extract. The ZnO-NPs have been investigated by X-Ray Diffraction (XRD), Ultra Violet-Visible (UV-Vis), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infra Red (FT-IR) analysis. XRD investigation confirms the crystalline structure of ZnO. The TEM images show triangular shape ZnO-NPs with sizes running from 15-20 nm. The XPS spectrum revealed the presence of Zn and O in the sample. Photoluminescence studies of ZnO-NPs displayed a sharp emission of blue band at 447 nm which is attributed to the defect structures in ZnO crystal. The presence of alcoholic, phenolic amide groups in the plant extracts is responsible for the formation of ZnO-NPs. The synthesized ZnO-NPs showed a very high antibacterial property against five bacterial strains such as Bacillus cereus,</div><div>Acinetobacter johnsonii, Achromobacter xylosoxidans, Achromobacter spanius and Chromobacterium pseudoviolaceum, with the highest zone of inhibition (ZOI) of 24 mm being shown against Achromobacter spanius strain. Further, the synthesized nanoparticles displayed excellent activities against four fungal strains, where a highest ZOI of 30 mm was observed against Penicillium citirinum, hence proving its high efficacy as antimicrobial agents.</div>

Biosynthesis of Triangular-Shape ZnO Nanoparticles Using Tecoma Stans and Its Antimicrobial Activity

<div>The present work reports the first green synthesis of zinc oxide nanoparticles (ZnO-NPs) using Tecoma stans leaf extract. The ZnO-NPs have been investigated by X-Ray Diffraction (XRD), Ultra Violet-Visible (UV-Vis), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infra Red (FT-IR) analysis. XRD investigation confirms the crystalline structure of ZnO. The TEM images show triangular shape ZnO-NPs with sizes running from 15-20 nm. The XPS spectrum revealed the presence of Zn and O in the sample. Photoluminescence studies of ZnO-NPs displayed a sharp emission of blue band at 447 nm which is attributed to the defect structures in ZnO crystal. The presence of alcoholic, phenolic amide groups in the plant extracts is responsible for the formation of ZnO-NPs. The synthesized ZnO-NPs showed a very high antibacterial property against five bacterial strains such as Bacillus cereus,</div><div>Acinetobacter johnsonii, Achromobacter xylosoxidans, Achromobacter spanius and Chromobacterium pseudoviolaceum, with the highest zone of inhibition (ZOI) of 24 mm being shown against Achromobacter spanius strain. Further, the synthesized nanoparticles displayed excellent activities against four fungal strains, where a highest ZOI of 30 mm was observed against Penicillium citirinum, hence proving its high efficacy as antimicrobial agents.</div>

Photocatalytic Activity of Bilayer TiO2/ZnO and ZnO TiO2 Thin Films

Thin film is a thin material that is resulting from the condensation of species through the deposition of atoms on the substrate. Thin films are usually used in the production of electronic devices, optical coatings, solar cells, and for decorative items. The bilayer of TiO2/ZnO and ZnO TiO2 thin films have some advantages such as can enhance the surface state and surface atomic mobility, which are useful for improving the photocatalytic activity. The motivation to a used double layer of ZnO and TiO2 is to enhance the properties and photocatalytic activity using the different deposition temperature between the layers. The structural of ZnO/TiO2 thin films were studied using X-Ray diffraction (XRD). Field Emission Scanning Electron Microscope (FESEM) was used to determine the surface morphology of ZnO/TiO2 thin films. The photocatalytic activity of ZnO/TiO2 thin films was analysed using the photodegradation of methylene blue (MB) solution. The XRD analysis revealed that highest anatase crystalline phase for TiO2 growth with orientation (1 0 1), while the ZnO crystal phase, zincite occurred at the highest intensity with (1 0 1) orientation.. The bilayer TiO2/ZnO thin film had the highest reaction rate, K, which is 0.0972 h-1 for photocatalytic activity. The characteristics of bilayer TiO2/ZnO and ZnO/TiO2 thin-film is strongly influenced by the calcination temperature and the presence and combination between the two types of materials.