NO2 Gas Sensing Properties of Screen Printed ZnO Thick Films

Zinc Oxide (ZnO) thick films were prepared on alumina substrate by using standard screen printing technique. These films were dried and fired at different temperatures between 700oC to 900oC for two hours in air atmosphere. The Morphological, Compositional and Structural properties of the ZnO thick films were performed by Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDX) and XRD technique respectively. Chemical composition of ZnO film samples changes with firing temperature showing non-stoichiometric behaviours. XRD study indicated the formation of polycrystalline ZnO films with hexagonal wurtzite structure. We explore NO2 sensing properties of the ZnO films

Study on Gas Sensing Performance of TiO2 Screen Printed Thick Films

Titanium dioxide (TiO2) thick films were prepared on alumina substrate by using screen printing technique. After preparation, the films were fired at temperature range 600 -1000 ºC for two hour. Morphological, compositional and structural properties of the film samples were performed by means of several techniques, including scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), X-ray diffraction techniques. We explore the various gases to study the sensing performance of the TiO2 thick films. The maximum response was reported to film fired at 800 0C for LPG gas at 350 0C operating temperature

Effect on H2S Gas Sensing Performance of Nb2O5 Addition to TiO2 Thick Films

Pure and Nb2O5 doped TiO2 thick films of various concentration ( 1 wt.%, 3 wt.%, 5 wt.%, 7 wt.% and 10 wt.%) were prepared on alumina substrate by using screen printing technique. After preparation, these films were fired at temperature 800 ºC for two hours in O2 atmosphere. Morphological, compositional and structural properties of the samples were performed by means of several techniques, including scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), X-ray diffraction techniques. In this paper, we report for the first time, H2S gas sensing phenomena observed in Nb2O5 doped-TiO2 screen-printed thick films. The surface resistance of thick films decreases when exposed to H2S gas. Low concentration of doping in Titania (TiO2) with Nb205 has shown significant enhancement in sensitivity (98.78 %) to H2S gas than pure TiO2 film at 200 0C with fast response and recovery time

Influence of Firing Temperature on Compositional and Structural Characteristics of ZrO2 Thick Films Gas Sensor

In this paper, we explore for the first time the compositional, morphological and structural properties of the ZrO2 thick films prepared by standard screen printing method and fired between 800 oC to 1000 oC for 2-hours in an air atmosphere. The material characterization was done by using XRD, X-ray energy dispersive analysis (EDAX), and scanning electron microscope (SEM). The deposited films were polycrystalline in nature. Also samples were found uniform and adherent to the alumina substrate. Effect of firing temperature on structural parameters such as grain size and surface area were calculated. The result indicates that grain growth can be increased by increasing firing temperature which is responsible for decreasing surface area. From the EDAX analysis it was found that the ZrO2 films are non- stoichiometric in nature which is due to semiconducting behavior of the films

Effect on Ethanol Gas Sensing Performance of Cu Addition to TiO2 Thick Films

The preparation, characterization and gas sensing properties of Cu loaded thick films with TiO2 semiconductor oxides have been investigated. These films of oxides were obtained by loading various concentrations (1 wt. %, 3 wt. %, 5 wt. %, 7 wt. % and 10 wt. %) of Cu in TiO2 on alumina substrate by using screen printing technique. Pure TiO2 was observed to be insensitive to ethanol gas. However, TiO2 film loaded with 10 wt. % Cu was observed to be highly sensitive to ethanol gas. The sample was observed to be oxygen deficient. The Ethanol gas sensing studies were carried out on a static gas sensing system under normal laboratory conditions. D.C. Resistance of TiO2 films were measured by half-bridge method in an atmosphere at different temperatures. The crucial gas response was found to ethanol gas at 300 0C and no cross response was observed to other hazardous and polluting gases. The effects of loading concentration on the gas sensitivity, selectivity, response and recovery of the sensor in the presence of ethanol gas were studied and discussed

Volumetric, viscometric and spectroscopic investigations of binary mixtures of o-chlorophenol with ethers

463-470Density and viscosity of o-chlorophenol with tetrahydrofuran, diphenyl ether and tertbutylmethyl ether at different temperatures and at atmospheric pressure and spectroscopic study at atmospheric temperature and pressure have been measured experimentally. The excess molar volumes and deviation in viscosities have been calculated across the mole composition and interpreted for the intra and intermolecular association among like and unlike molecules. The influence of structure of components on the existing interaction has been revealed by the behavior of the excess parameters. The sign and magnitude of excess parameters clearly indicates the presence of specific interactions among the components. These parameters have been studied on the basis of dipole-dipole interaction and hydrogen bonding. The molecular structure and vibrational spectra have been investigated by Density Functional Theory (DFT) using standard B3LYP functional and 6-31G (d, p) basis set. Computed values at DFT (B3LYP)/6-31G (d, p) have been analyzed and their characterization has been made with the help of Gauss view visualization program utilizing the data obtained from the Gaussian 03 calculation

Formulation and Characterization of Cr2O3 Doped ZnO Thick Films as H2S Gas Sensor

Cr2O3 doped ZnO thick films have been prepared by screen printing technique and firing process. These films were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), and EDX. H2S gas sensing properties of these films were investigated at different operating temperatures and different H2S concentrations. The 7 wt. % Cr2O3 doped ZnO thick films exhibits excellent H2S gas sensing properties with maximum sensitivity of 99.12 % at 300 oC in air atmosphere with fast response and recovery time

Study of Microstructural Parameters of Screen Printed ZnO Thick Film Sensors

This paper explores the compositional, morphological and structural properties of ZnO thick films prepared by a standard screen printing method and fired between 650 oC to 900 oC for 2 hours in an air atmosphere. The material characterization was done using X-ray energy dispersive analysis (EDX), X-ray diffraction (XRD) and a scanning electron microscope (SEM). The deposited films were polycrystalline in nature having the wurtzite (hexagonal) structure with a preferred orientation along the (101) plane. The result shows that the wt. % of Zn was found to be 80.39, 82.66 and 83.47 % for firing temperatures of 700, 800 and 900 oC respectively may be due to the release of excess oxygen. The effect of the firing temperature on structural parameters such as the crystallite size, specific surface area, texture coefficient, RMSmicrostrain, dislocation density and stacking fault probability have been studied. The results indicate that grain growth can be increased by increasing the firing temperature which is responsible for decreasing the RMSmicrostrain, stacking fault probability and dislocation density in ZnO thick films. The crystallite size changes from 18.58 nm to 37.23 nm with respect to the increase in the firing temperature