A.R. Bari

SPRAY-PYROLIZED NANOSTRUCTURED CUO THIN FILMS FOR H2S GAS SENSOR

Nanostructured copper oxide (CuO) thin films were prepared by spray pyrolysis technique. X-ray diffraction was used to investigate the structural properties. Surface morphology was studied using scanning electron microscopy. Microstructure was studied using a transmission electron microscope, and energy-dispersive X-ray analysis was used to determine the elemental composition of prepared nanostructured CuO thin film. Gas-sensing performance was conducted using static gas-sensing system, at different operating temperatures in the range of 200°C to 400°C for the gas concentration of 100 ppm. The maximum sensitivity (S = 872) to H2S was found at the temperature of 250°C. Quick response (2 s) and fast recovery (5 s) are the main features of this film.

Ultrasonically synthesized nanocrystalline ZnO powder‐based thick film sensor for ammonia sensing

Purpose – The purpose of this paper is to show how to obtain better response, selectivity and fast response and recovery from nanocrystalline ZnO‐based gas sensors as compared to conventional materials.Design/methodology/approach – Nanocrystalline ZnO powders were prepared from the ultrasonic spray pyrolysis method. Aqueous solution of zinc acetate was atomized using ultrasonic atomizer. The aerosol generated was fed to the reaction furnace for pyrolysis. Nanocrystalline ZnO crystallites were collected using simple but novel trapping system. Thick film resistors of this powder were fabricated using screen printing technique.Findings – As‐prepared powder was studied using X‐ray diffraction, transmission electron microscopy and scanning electron microscopy to know structure, size of nanocrystallites and microtopography, respectively. Absorption spectroscopy is used to determine the band gap energy. The gas‐sensing performance of this film was tested.Originality/value – The sensor was found to be the most se...

Synthesis of ZnO Nanocrystalline Powder From Ultrasonic Atomization Technique, Characterization, and its Application in Gas Sensing

Nanocrystalline zinc-oxide (ZnO) powders were prepared from the ultrasonic atomization method. An aqueous solution was atomized by using the ultrasonic atomizer operating at 2.1 to 2.3 MHz. The generated droplets were fed to the reaction furnace for pyrolysis. Nanocrystalline ZnO crystallites were collected by using a simple but novel trapping system, and prepared powder was characterized using X-ray diffractogram, transmission electron microscopy, scanning electron microscopy, and absorption spectroscopy. Nanostructured thick-film sensors of this powder were prepared by using the screen printing technique. The gas sensing performance of this film was tested. The sensor was found to be most sensitive to NH3. The results were discussed and interpreted.

Effect of precursor concentrations on structural, microstructural and optical properties of nanocrystalline ZnO powder synthesized by an ultrasonic atomization technique

In this paper, we report on the effect of concentration on nanocrystalline ZnO powder prepared by an ultrasonic atomization technique, which is a promising method because of its simplicity, inexpensiveness and safety. The morphology and size of ZnO nanocrystallites associated with nanopowder were characterized by transmission electron microscopy (TEM). It revealed that the powder consisted of nanocrystallites with grain sizes between 8 and 15 nm. These values match the grain sizes (8–14 nm) calculated from x-ray diffraction (XRD). The XRD and TEM studies of ZnO nanopowder showed that crystallite sizes were observed to increase with an increase in the concentration of solution. The d values calculated from electron diffraction patterns (TEM) of ZnO nanopowder were also in agreement with the d values calculated from XRD. The synthesized nanopowders exhibited a direct band gap (Eg) in the range of 3.36–3.42 eV.

Ultrasonically Sprayed Nanostructured Perovskite-Type CdSnO 3 Thin Films for Sensing of CWA Simulants

CdSnO₃ thin films were prepared using ultrasonic spray pyrolysis technique. The structural, microstructural, and optical properties of the films were studied using X-ray diffraction, transmission electron microscopy, and UV-VIS spectroscopy, respectively. The sensing performance of a typical film was tested for chemical warfare agent simulants, such as, 2-chloroethyl ethyl sulfide C₄H₉ClS CEES (CEES), dimethyl methyl phosphonate C₃H₉O₃P (DMMP), and 2-chloroethyl phenyl sulfide C₈H₉ClS (CEPS). The simulant sensing performance of CdSnO₃ thin-film-based sensor was tested. CdSnO₃ thin-film-based sensor was observed to be more sensitive to CEES as compared with DMMP and CEPS. The results were discussed and interpreted.

Effect of molarity of precursor solution on physical, structural, microstructural and electrical properties of nanocrystalline ZnO thin films

Abstract Nanocrystalline ZnO thin films were successfully prepared using simple spray pyrolysis technique. Zinc acetate dihydrate and deionised water was used as starting precursor solution. Nanocrystalline ZnO thin films were prepared by varying molarities of precursor solution from 0·025 to 0·1M. The films were characterised using X-ray diffractogram (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and element composition was studied using an energy dispersive spectrophotometer (EDAX).The film thickness was measured using weight difference method. Thermoelectric power measurements were conducting using TEP set-up, electrical conductivity measured with the help of two probe method. The grain size and number of unit cell were observed to be increase with increase in molarities of precursor solution. From XRD, it was observed that the molarities of precursor solution goes on increasing with increases in texture coefficient for plane (002) while it is decreases for plane (101). Effect of molarities of precursor solution on physical, structural, microstructural and electrical properties of these films was studied and presented in the present investigation.

Preparation, characterization and gas sensing performance of BaTiO3 nanostructured thin films

Spray pyrolysis techniques was employed to prepare BaTiO3 thin films. AR grade solutions of Barium chloride (0.05 M) and Titanium chloride (0.05 M) were mixed in the proportion of 30:70, 50:50 and 70:30. The solutions were sprayed on quartz substrate heated at 350°C temperature to obtain the films. These thin films were annealed for a two hours at 600°C in air medium respectively. The prepared thin films were characterized using XRD, FESEM, EDAX, TEM. The electrical and gas sensing properties of these films were investigated. 50:50 film showed better response to Liquid Petroleum Gas (LPG) as compare 30:70 and 70:30 films.Spray pyrolysis techniques was employed to prepare BaTiO3 thin films. AR grade solutions of Barium chloride (0.05 M) and Titanium chloride (0.05 M) were mixed in the proportion of 30:70, 50:50 and 70:30. The solutions were sprayed on quartz substrate heated at 350°C temperature to obtain the films. These thin films were annealed for a two hours at 600°C in air medium respectively. The prepared thin films were characterized using XRD, FESEM, EDAX, TEM. The electrical and gas sensing properties of these films were investigated. 50:50 film showed better response to Liquid Petroleum Gas (LPG) as compare 30:70 and 70:30 films.