Ceramic Nanomaterials Based on the Barium and Titanium Compounds, Prepared by the Sol - Gel Method, for Elecrotechnical Applications

2011 ◽  
Vol 56 (4) ◽  
pp. 1057-1064
Author(s):  
K. Kogut ◽  
B. Zboromirska-Wnukiewicz ◽  
K. Kasprzyk

Ceramic Nanomaterials Based on the Barium and Titanium Compounds, Prepared by the Sol - Gel Method, for Elecrotechnical Applications This paper describes the sol - gel method barium and titanium compounds materials obtaining, which their physicochemical parameters could be competitive with the materials obtained by classic methods. Additionally dielectric thin layers was obtained with the use of spin and dip coaters. Based on selected precursor elements which form appropriate crystal net, the capacitance construction was created. Dielectric in this contraction was a barium titanate with high electrical permittivity and small grain size. The optimal dry, calcinations and sintering temperature of the dielectric with base was determined. On that capacitor the microscopic analysis with the use of scanning electron microscope (SEM) was carried out. The thickness of the dielectric layer and electrical parameters use by impedance analyzer Solatron SI 1260 was carried out. The capacitance, dielectric loss and electrical permittivity was carried out, cooperative influence of the frequency and temperature on the measurements was determined. The best results had a samples sintered in the 1000°C. The electrical permittivity for measurements in few Hertz for the samples with the base of nickel and BaTiO3 layer coated by spin and dip coaters, in the room temperature and measurements for few Hertz, amount to 4700. The electrical capacity for low frequency was about 3,2·10-8F.

2019 ◽  
Vol 8 (3) ◽  
pp. 209
Author(s):  
Fatima Zahra Krimech ◽  
Salaheddine Sayouri ◽  
Taj-Edine Lamcharfi ◽  
Fatima Zahra Ahjyaje

<p>Pure phase Li<sub>2</sub>TiO<sub>3 </sub>nano-particles were synthesized by the sol-gel method and the structural properties were examined with X-ray diffraction (XRD) technique. The latter showed that these materials, heat treated at relatively low temperature 900°C during 4h compared to the conventional solid-state reaction which calcination temperature is about 900–1100°C for 10 h; crystallize in the monoclinic phase without the presence of secondary phases. The microstructure of the LT ceramic (sintered at 1100°C) were determined by SEM and a good crystalline nature was observed with an average of granular size 2 μm. Moreover, the impedance spectroscopy showed at a higher temperature of 500°C the low-frequency arc due either to the grain boundary or sample-electrode charge transport processes.</p>


2019 ◽  
Vol 293 ◽  
pp. 83-95
Author(s):  
Marek Szindler

The use of thin films in optoelectronic and photovoltaic devices is aimed at improving the physical properties of the substrate material. The modification of the surface of the silicon substrate is thus one of the greatest challenges in research on photovoltaic materials, in order to achieve even greater efficiency or better adapt their properties depending on the application. The technologies of applying layers vary depending on the effect to be obtained and the material from which the layer is formed. In practice, the most common method is chemical vapor deposition and physical vapor deposition, and the most commonly applied optical materials are SiO2, TiO2 and Si3N4.This paper presents the results of investigations on morphology and optical properties of the prepared aluminium oxide thin films. Thin films were prepared with use of sol-gel spin coating method. Surface morphology studies were carried out using an atomic force microscope. To characterize the surface of the thin films, 3D images and histograms of the frequency of individual inequalities were made. In order to characterize the optical properties of Al2O3 thin films, the reflectance and light transmission tests were performed using a spectrophotometer. Optical constants were determined using a spectroscopic ellipsometer. Results and their analysis show that the sol-gel method allows the deposition of homogenous thin films of Al2O3 with the desired geometric characteristics and good optical properties. Uniform, continuous thin layers with a roughness not exceeding a few nanometres were deposited. Their deposition enabled to reduce the reflection of light from the polished substrate below 15% in a wide range (425-800nm) while maintaining high transparencies (over 90%). The obtained results causes that mentioned thin films are good potential material for optics, optoelectronics and photovoltaics.


1990 ◽  
Vol 25 (5) ◽  
pp. 2569-2572 ◽  
Author(s):  
L. Murawski ◽  
L. Wicikowski ◽  
O. Gzowski ◽  
I. Davoli ◽  
S. Stizza ◽  
...  

2013 ◽  
Vol 200 ◽  
pp. 22-26 ◽  
Author(s):  
Pawel Popielarski ◽  
Kazimierz Paprocki ◽  
Waclaw Bala ◽  
Agnieszka Banaszak-Piechowska ◽  
Karolina Walczyk ◽  
...  

Confocal Raman spectroscopy has been applied to investigate blend polycarbonate and ZnO thin layers with different thicknesses and different content of ZnO. The admittance spectroscopy have been applied to correlation of optical and electrical properties of these layers used in electroluminescence diodes and photovoltaic cells. The I-V (DC and AC) characteristics and thermally stimulated current (TSC) have been applied to the study of the deep levels in ZnO thin films grown by sol-gel method onto Si substrates. The surface spectroscopy morphology of the samples were investigated by scanning microscopy and X ray diffraction.


2019 ◽  
Vol 8 (3) ◽  
pp. 209-212
Author(s):  
Fatima Zahra Krimech ◽  
Salaheddine Sayouri ◽  
Taj-Edine Lamcharfi ◽  
Fatima Zahra Ahjyaje

Pure phase Li2TiO3 nano-particles were synthesized by the sol-gel method, and the structural properties were examined with X-ray diffraction (XRD) technique. The latter showed that these materials, heat treated at relatively low temperature 900°C during 4h compared to the conventional solid-state reaction which calcination temperature is about 900–1100°C for 10 h; crystallize in the monoclinic phase without the presence of secondary phases. The microstructure of the LT ceramic (sintered at 1100°C) were determined by SEM, and good crystalline nature was observed with an average of granular size 2 μm. Moreover, the impedance spectroscopy showed at a higher temperature of 500°C the low-frequency arc due either to the grain boundary or sample-electrode charge transport processes.


2015 ◽  
Vol 1 (2) ◽  
pp. 21-26 ◽  
Author(s):  
Mohammad Hossein Sarfi ◽  
Mohammad Ghadimi ◽  
Arash Babaee

Hydrogen Sulfide (H2S) is a toxic gas that has adverse effects on human health as well as the oil and gas industry; hence, it is important to identify its characteristics appropriately. The present research was aimed to study the sensing behavior of SnO2-CuO thin layers obtained by the sol-gel method. The working temperature in the present investigation was the environment temperature and the resistance curves related to the sensing behavior were obtained. The microstructure of the covered layers was studied using Field Emission Scanning Electron Microscope (FE-SEM), AFM and XRD analysis method. The thin layer of SnO2-CuO optimized with sensory characteristics was coated using sol-gel method and were heated for 5 hours at 400 °C. The best response number was 1180 (no unit), the response time was 43 seconds and the least recovery time was 210 seconds. Moreover, it had a longer response time compared to the unheated sample, but the response number and the recovery time were improved due to the thermal treatment.


Author(s):  
Maria Zaharescu ◽  
Dana Cristea ◽  
Paula Obreja ◽  
Luminita Predoana ◽  
Mariuca Gartner ◽  
...  

2012 ◽  
Vol 2 (8) ◽  
pp. 1111 ◽  
Author(s):  
Shunsuke Murai ◽  
Marc A. Verschuuren ◽  
Gabriel Lozano ◽  
Giuseppe Pirruccio ◽  
A. Femius Koenderink ◽  
...  

Open Physics ◽  
2005 ◽  
Vol 3 (3) ◽  
Author(s):  
Abdoljavad Novinrooz ◽  
Masoomeh Sharbatdaran ◽  
Hassan Noorkojouri

AbstractThin layers of tungsten trioxide have been prepared from an aqueous solution of peroxotungstic acid (PTA) using the sol-gel method. Compositional, structural and optical characteristics of WO3 coated on indium tin oxide (ITO) conductive glass substrates were studied using X-ray diffractometery (XRD), cyclic voltammetery (CV), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Monoclinic and triclinic crystalline structures for thin film and powdered WO3 were confirmed by XRD analysis. SEM micrograph of annealed samples revealed micro cracks due to a decrease in density and a contraction of layers. EDX analysis showed that 1∶2 ratio of oxygen and tungsten atoms in the prepared films is obtained at heat treatment temperatures higher than 200 °C. Furthermore, the annealed samples showed very good electrochromic behavior in cyclic voltammetery studies. Refractive index “n” and extinction coefficient “k” values were found to be reduced by increasing the wavelength and decreasing the temperature.


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