Faculty Publications
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Item A balancing between super transparency and conductivity of solution combustion derived titanium doped indium oxide: Effect of charge carrier density and mobility(Elsevier B.V., 2018) Pujar, P.; Vardhan, R.V.; Gupta, D.; Mandal, S.In this contribution, super transparent (~100%) and conducting In14Ti1O23 (Titanium doped Indium oxide; InTiO) films were reported via solution combustion processing with acetylacetone as fuel. Both bulk-powder and thin film systems were studied and revealed the efficacy of low temperature combustion synthesis which yielded crystalline InTiO powder at 150 °C and its film counterpart had shown pronounced crystalinity with temperature. Also, all films with varying annealing temperature were smooth with rms value ranging from 0.29 nm to 1.9 nm. In addition, the charge carrier density in all films found to be of the order 1019 cm?3, possessing highest transparency nearly equals to uncoated glass at an annealing temperature of 350 °C having maximum of ~67% metal-oxygen-metal framework (or lattice oxygen) confirmed via X-ray photoelectron spectroscopy. Also, the highest conductivity of 20 S/cm at an annealing temperature of 450 °C clearly conveyed the potential of solution combustion processing in the fabrication of ultra-transparent InTiO films with no sophistication in the film fabrication. © 2018Item Investigation of sintering kinetics and morphological evolution of silver films from nano-dispersion(Springer Verlag service@springer.de, 2018) Pujar, P.; Anusha, P.; Gupta, D.; Mandal, S.The present study aimed at investigating the sintering kinetics and the mechanism of achieving uniform film morphology from silver nano-dispersion through evaporation of the solvent. A tuned time elapse between drop casting of silver dispersion and the annealing (dwell-time) acted as the decision maker in engineering the morphology: ring stain (infinite dwell-time), uniform deposit (variable dwell-time) and dot formation (zero dwell-time). Three distinct dwell-times (10, 20 and 30 min) are chosen for the study at different temperatures (120 to 250 °C) and the conclusion is derived based on the profile of the deposit. The frozen morphology that resulted from the evaporation goes through the debonding of surfactant with simultaneous sintering to minimize the surface energy. A linear isothermal sintering model comprising initial grain size, grain growth parameter, annealing time and fractional porosity helps to predict the grain size post-annealing. Theoretical predictions of grain sizes are well matched with experimental ones. The grain growth parameter which shows an upward trend with the annealing temperature is mainly due to a reduction in the porosity and the increase in the fraction of solid–solid interface which shows betterment in the percolation paths available for the movement of carriers. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.Item Facile in situ formation of high conductive Ag and Cu x O y composite films: a role of aqueous spray combustion(Springer New York LLC barbara.b.bertram@gsk.com, 2019) Salian, A.; Pujar, P.; Mandal, S.In the present contribution, in situ formation of low-temperature high conductive composite films composed of pure silver and oxides of copper (Cu x O y where, x = y = 1 for CuO and x = 2, y = 1 for Cu 2 O), are presented through spray combustion with a balanced stoichiometric redox reaction. High electrical conductivity (~ 7.8 × 10 5 S/cm) was retained in the composite film at an annealing temperature of 170 °C with matrix silver phase being 50% by volume. Whereas electrical conductivity of spray combustion processed pure silver is found to be ~ 2 × 10 6 S/cm. In situ formation of the composite film directly from the silver and cupric nitrate aqueous precursor solution through spray combustion proves it to be compositionally tunable with minimal usage of noble metal. Presence of Ag and Cu x O y is confirmed by X-ray diffraction and X-ray photoelectron spectroscopy. The ratio of Cu 1+ /Cu 2+ in the composite is found to be 0.54 and 0.43 at an annealing temperature of 170 °C and 400 °C respectively. The transformation of Cu 2 O to CuO is highly a thermally activated phenomenon; as the vacancy driven electrical conductivity is more in Cu 2 O than CuO, stabilization of Cu 2 O at a lower temperature is desired. The composite electrode can have potential applications in optoelectronics, printed electronics and catalysis. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.