http://localhost:8080/xmlui/handle/123456789/6645 2026-04-22T21:49:11Z http://localhost:8080/xmlui/handle/123456789/6674 Title: Effect of annealing temperature on SnS thin films for photodetector applications Authors: S.S. Hegde Abstract: Tin sulfide (SnS) thin films were deposited at room temperature (RT) by thermal evaporation method and subsequently annealed at 150–350 CinN atmosphere. The influence of annealing temperature on composition, structural, morphological and optical properties of the thin films has been investigated. X-ray diffraction (XRD) analysis and Raman studies confirmed the formation of single phase SnS films at RT and annealed up to 300 C. The crystallite size increased from 24 nm for as-deposited film to 37 nm for the 300 C annealed film and further reduced to 18 nm for the 350 C annealed film. The film annealed at 200 C was found to have better morphological features with (111) preferred oriented crystallites. The absorption coefficient, optical band gap (E ) of the deposited films were estimated from the optical transmittance measurements. Photodetectors are fabricated by depositing Ag contacts on SnS thin films using a metal mask and photo response was tested under dark and illumination conditions using 532 nm laser of varying power intensities. The photodetectors performance is evaluated using responsivity (R), external quantum efficiency (EQE), and specific detectivity (D*). The specific detectivity of 6.8 9 10 Jones obtained in the present study is nearly two orders of magnitude greater than that reported earlier. 2022-01-01T00:00:00Z http://localhost:8080/xmlui/handle/123456789/6673 Title: Cu-Al OXIDE NANOCOMPOSITE-BASED EXTERNAL FILTERS FOR GAS PURIFICATION FROM PETROL AUTOMOBILE EXHAUST Authors: Prashant S. Hatti Abstract: Currently existing exhaust gas catalytic converters in automobiles are expensive because they use precious metals, such as Pt, Pd, and Rh, as active components in conversion catalysts. However, they are unable to convert all toxic gases (e.g., CO, NO , and hydrocarbons) into less harmful pollutants before emission to the atmosphere. This is more so in case of automobiles with old petrol engines and fuel types (standard unleaded petrol) causing air pollution. In this work, equimolar copper–aluminium oxide-based nanocomposites devoid of precious metals were prepared using cost-effective wet chemical methods rendering a nano crystalline-amorphous catalyst matrix and tested for NO x x reduction. An external filter with the proposed catalyst was developed and used at the tailpipe of a 350 cc petrol engine to assess the impact on exhaust gas emissions. We also studied the growth and composition of chemically stable composite and analyzed their functional properties using X-ray diffraction, adsorption, and gas chromatography. Nanocomposite was dip coated on ceramic honeycomb substrates and mounted inside welded casings to fabricate an external filter. Emission tests were carried out with and without the exhaust filter. A reduction in NO along with that of CO and hydrocarbons from the flue gas by about 45, 12, and 32%, respectively, was obtained when the tailpipe emissions were treated at ambient conditions. To the best of our knowledge, this is one of the primary studies on a simple and well-designed Cu-Al oxide nanocomposite matrix for three-way catalysis during exhaust flue gas treatment. 2022-01-01T00:00:00Z http://localhost:8080/xmlui/handle/123456789/6672 Title: Concomitant structural and ferroelectric properties of Sr2Bi4Ti5O18 ceramics sintered with perovskite Authors: S.S. Hegde Abstract: Lead free piezoelectric ceramics with the composition(1-x)Sr ☆ e þ x [(K 0.41 Na 0.53 Li 0.06 )(Nb 0.89 Sb 0.06 Ta 0.05 )O ] (where x ¼ 0, 0.05, 0.10, 0.15 and 0.20) were synthesized using the pre-reacted Sr 2 Bi 4 Ti 5 O 18 (SBT) and [(K 3 0.41 Na 0.53 Li 0.06 )(Nb 0.89 Sb 0.06 Ta 0.05 )O ](KNLNST) powders via solid-state reaction carried out at 1130 3 C. Based on X-ray diffraction studies it was confirmed that only less than 0.15 mol of KNLST was soluble in the SBT phase. Raman spectra analyses for these samples revealed that A and B site cations from KNLNST perovskite phase were found to occupy A and B site cations of SBT. There was an increase in the grain size with the increase in x and grains with plate-like morphology were seen in these samples when observed through a scanning electron microscope (SEM). The measured values of relative permittivity (rational electric permittivity) (300 at 1 MHz), dielectric loss (0.013 at 1 MHz), and maximum polarization (5.95 μC/cm ) for the samples with the composition x ¼ 0.2 were found to be superior to that of undoped SBT. The decrease in Curie temperature with the increase in x for all the samples under study was confirmed through temperaturedependent dielectric measurements. 2022-02-01T00:00:00Z http://localhost:8080/xmlui/handle/123456789/6671 Title: Biosensing of Catechol via amperometry using laccase immobilized nickel oxide graphite modified screen-printed electodes Authors: B. Narasimhamurthy Abstract: Biosensing of Catechol via amperometry using laccase immobilized nickel oxide graphite modified screen-printed electodes B. Narasimhamurthy 2022-04-01T00:00:00Z