Karolina Moszak; Anna Szczurek; Bartosz Babiarczuk; Beata Borak; Justyna Krzak
Abstract
Ultraviolet light influences materials structure causing the decomposition and degradation of organic compounds. One of the ideas to reduce the harmful effects of light is to protect materials by sol-gel coatings. ZnO sol-gel thin films on a glass substrate were obtained as optical filters. The filter ...
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Ultraviolet light influences materials structure causing the decomposition and degradation of organic compounds. One of the ideas to reduce the harmful effects of light is to protect materials by sol-gel coatings. ZnO sol-gel thin films on a glass substrate were obtained as optical filters. The filter effect of synthesized coatings stabilized in different temperatures were characterized by UV-Vis transmittance spectroscopy. The morphology and elemental composition of coating surface was determined by SEM and EDX. Scratch resistance and adhesion have been evaluated by scratch test. The coatings present high transparency in the visible region and absorption in the UV region (270-360 nm). The results suggest that the obtained materials have proper parameters for UV optical filters.
C. Jayachandraiah; G. Krishnaiah
Abstract
Pure and erbium (1.30, 1.79, 2.83 and 3.53 at. %) doped ZnO nanoparticles are synthesized by wet chemical co-precipitation method. The synthesized samples are characterized by powder X-ray diffraction (XRD), energy-dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM), Raman spectroscopy, ...
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Pure and erbium (1.30, 1.79, 2.83 and 3.53 at. %) doped ZnO nanoparticles are synthesized by wet chemical co-precipitation method. The synthesized samples are characterized by powder X-ray diffraction (XRD), energy-dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM), Raman spectroscopy, UV–visible diffusion reflectance spectroscopy (DRS) and LCR Impedance spectroscopy. The XRD measurements confirmed the hexagonal wurtzite structure of all samples and size of the particle is found to be decreased with Er content. TEM images show spherical shape with more agglomeration in Er doped ZnO nanoparticles. Raman spectra confirmed the hexagonal wurtzite structure of pure and Er doped ZnO nanoparticles with E2 (high) mode at 438 cm -1 and presence of other possible defects. UV visible DRS shows decrease in the band gap with increasing Er 3+ in ZnO host. Dielectric constant, dielectric loss factor and ac conductivity properties were decreased with Er dopant in tune with Maxwell -Wagner principle and surface-orientation polarizations.
K. Chennakesavulu; G. Ramanjaneya Reddy; S. Sanjeevi Prasath; S. Supriya; S. Sivanesan
Abstract
In-situ synthesis of ZnO and Nb2O5 composites was carried out in alkaline medium. The obtained composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, diffuse reflectance UV-Vis spectrophotometer (DRS), Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy ...
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In-situ synthesis of ZnO and Nb2O5 composites was carried out in alkaline medium. The obtained composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, diffuse reflectance UV-Vis spectrophotometer (DRS), Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area method, N2-sorption isotherms, Thermo gravimetric analysis (TGA), Particle size and Field emission scanning electron microscopy (FESEM/EDX). The synthesized composite was used as photocatalyst in the degradation of reactive red-198 (RR), methylene blue (MB) and 3-chloro phenol (3CP) under visible light irradiation. The catalytic activity and removal percentage of dye was determined by the spectrophotometric method, it indicates high percentage of degradation for the ZnO:Nb2O5 composite. The kinetic parameters were found to obey pseudo-first order oxidation reaction, which may be due to the fixed amount of the catalyst and concentration of the dye solution. The recycled and purified composites of ZnO:Nb2O5 was tested the catalytic activity and was compared with that of the fresh catalyst.
Rajkumar Patra; Santanu Ghosh; Himani Sharma; Vasant D. Vankar
Abstract
A comparative study of electron field emission (FE) property of pristine mutiwalled carbon nanotubes (p-CNTs), zinc (Zn) coated CNTs (Zn-CNT), zinc oxide (ZnO) coated CNTs (ZnO-CNT) is reported. CNTs were synthesized on p-type Si (100) by microwave plasma enhanced chemical vapor deposition (MPECVD) method ...
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A comparative study of electron field emission (FE) property of pristine mutiwalled carbon nanotubes (p-CNTs), zinc (Zn) coated CNTs (Zn-CNT), zinc oxide (ZnO) coated CNTs (ZnO-CNT) is reported. CNTs were synthesized on p-type Si (100) by microwave plasma enhanced chemical vapor deposition (MPECVD) method and the sample was divided into three parts. On two of these parts, a thin layer (~ 4nm) of Zn film was deposited. One of these (Zn-CNT) was kept for analysis and the other one was annealed in oxygen (O2) atmosphere at 520° C for 60 minutes to get ZnO coated CNT film (ZnO-CNT). Scanning electron microscope (SEM) analysis confirmed CNT formation as well as Zn and ZnO coating on the top of p-CNT films. Further, energy-dispersive X-ray spectroscopy (EDX) results confirmed the presence of zinc and oxygen in these two samples. A detailed field emission study performed in these films give following results: (i) lowest turn-on field (electric field required to produce 10 μA/cm 2 current density) and threshold fields (electric field required to produce 100 μA/cm 2 current density) for pristine sample (3.3 V/μm and 5.1 V/μm respectively), followed by ZnO-CNT sample (3.7 V/μm and 6.3 V/μm respectively); (ii) highest temporal stability in current density versus field (J-E characteristics) in ZnO-CNT film as compared to other two, (iii) highest field enhancement factor in ZnO-CNT films as compared to other two. The FE results are correlated with microstructures of the samples as revealed by micro-Raman spectroscopy and transmission electron microscopy (TEM) studies.
Oman Zuas; Harry Budiman; Nuryatini Hamim
Abstract
The ZnO nanoparticles (ZnO NPs) were synthesized by co-precipitating method followed by calcining at 500 o C for 4 h. The characterization data show that the synthesized ZnO NPs were present in hexagonal wurtzite structure and space group P63mc with high purity and good crystalline nature. The synthesized ...
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The ZnO nanoparticles (ZnO NPs) were synthesized by co-precipitating method followed by calcining at 500 o C for 4 h. The characterization data show that the synthesized ZnO NPs were present in hexagonal wurtzite structure and space group P63mc with high purity and good crystalline nature. The synthesized ZnO NPs were tested for decolorization of congo red (CR) dye under microwave irradiation using microwave induced catalytic (MIC) method. The investigation results showed that the microwave induced ZnO NPs process could effectively decolorize the CR dye with the efficiency approaches 90.63% in a short contact time under given condition of 10 mg/l CR dye, 300 watt of microwave power, 3 min of contact time, and 3 g/l of catalyst dosage. Since the microwave-induced catalytic process in this study is noticeable, the microwave technology coupled with ZnO NPs as catalyst may have synergistic effects on the decolorization of CR dye giving high degradation ratio in short reaction time. Therefore, the microwave technology can be used as an alternative option to enhance the catalytic activity of metal nanoparticles dealing with removal of various industrial dyes containing wastewater.
Wei Wu; Shaofeng Zhang; Xiangheng Xiao; Changzhong Jiang
Abstract
A novel two-stage zinc oxide (ZnO) hexagonal microprisms was successfully synthesis via a hydrothermal route on a nickel (Ni) thin films. The Ni thin films are deposited by using magnetron sputtering onto Si (100) substrate. The formation of the secondary structure and optical properties of ZnO microprism ...
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A novel two-stage zinc oxide (ZnO) hexagonal microprisms was successfully synthesis via a hydrothermal route on a nickel (Ni) thin films. The Ni thin films are deposited by using magnetron sputtering onto Si (100) substrate. The formation of the secondary structure and optical properties of ZnO microprism have been investigated and the formation mechanism has been discussed. The results illustrate the Ni substrate is a key factor to grow the two-stage ZnO, and the photoluminescence (PL) emission peak at 389 nm reveals that the high crystal quality of these nanorods. ZnO with its excellent luminescent properties and the controllable nanostructures will hold promise for the development of photonic devices.
Subhash B. Kondawar; Smita A. Acharya; Sanjay R. Dhakate
Abstract
ZnO in different nanostructures were synthesized by microwave assisted hydrothermal route. Different experimental conditions such as microwave irradiation power, exposure time have been investigated to reveal the process of formation of the ZnO nanostructures. It was revealed that the microwave exposure ...
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ZnO in different nanostructures were synthesized by microwave assisted hydrothermal route. Different experimental conditions such as microwave irradiation power, exposure time have been investigated to reveal the process of formation of the ZnO nanostructures. It was revealed that the microwave exposure time plays a vital role in determining the diameter of the rods. The interaction of microwaves with the growth units of ZnO was systematically investigated to explain formation of different structural geometry of ZnO on nanoscale. ZnO nanostructures consisted of flower-like, sword-like, needle-like and rods-like structures were prepared by microwave assisted hydrothermal process at different conditions of microwave power and irradiation time. The ZnO nanostructures are in hexagonal phase. It is considered that microwave can interact with growth units of ZnO to generate active centers on the surface of ZnO nuclei so that needle-like ZnO rods are created on those sites, resulting in the formation of the flower-like ZnO nanostructures. Polyaniline - ZnO nanocomposites (PZ) in various weight % of nanostructure ZnO were synthesized by the chemical oxidation method in sulphuric acid medium using ammonium persulphate as oxidant at 276K. The synthesized polymer nanocomposites were characterized by XRD, FTIR and UV-VIS spectroscopy.
Ravindra P. Singh; Vineet K. Shukla; Raghvendra S. Yadav; Prashant K. Sharma; Prashant K. Singh; Avinash C. Pandey
Abstract
Herein, we are reporting a novel biological approach for the formation of zinc oxide (ZnO) nanoparticles using Maddar (Calotropis procera) latex at room temperature. X-Ray diffraction (XRD) pattern reveals the formation of ZnO nanoparticles, which shows crystallinity. Transmission electron microscopy ...
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Herein, we are reporting a novel biological approach for the formation of zinc oxide (ZnO) nanoparticles using Maddar (Calotropis procera) latex at room temperature. X-Ray diffraction (XRD) pattern reveals the formation of ZnO nanoparticles, which shows crystallinity. Transmission electron microscopy (TEM) suggested particles size and shape in the range of 5-40 nm. Scanning electron microscopy (SEM) image reveals that the particles are of spherical and granular nature. UV-Vis absorption shows characteristic absorption peak of ZnO nanoparticles. Photoluminescence (PL) studies were performed to emphasize its emission properties. This simple and cost-effective biological approach for the formation of ZnO NPs has a promising application in biosensing, electronics and photonics.
