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    Development of low temperature stoichiometric solution combustion derived transparent conductive ternary zinc tin co-doped indium oxide electrodes
    (Royal Society of Chemistry, 2017) Pujar, P.; Gandla, S.; Singh, M.; Gupta, B.; Tarafder, K.; Gupta, D.; Noh, Y.-Y.; Mandal, S.
    Here, the development of transparent conductive zinc tin co-doped indium oxide (IZTO: In1.4Sn0.3Zn0.3O3) ternary electrodes is addressed through low temperature solution combustion processing. Optimization of fuel to oxidizer ratio offers low temperature (?130 °C) of combustion with balanced redox reaction. The thin films of IZTO annealed at different temperatures showed a decreasing trend in the resistivity with a fixed order of 10-2 ? cm and the film with a highest Hall mobility of 5.92 cm2 V-1 s-1 resulted at 400 °C. All the films with different temperatures of annealing were smooth (rms ? 2.42 nm) in nature and the IZTO film annealed at 200 °C is 83% transparent in the visible spectra. The effective band gap of 0.9 eV determined from first-principles density functional theory gives clear evidence for the conducting nature of IZTO. The thin film transistor fabricated with IZTO as a gate electrode with poly(methyl methacrylate) and pentacene as the dielectric and channel material, respectively, exhibited a saturation mobility of 0.44 cm2 V-1 s-1 and Ion/Ioff ratio of 103. Further, the printability of the IZTO combustible precursor is established which resulted in anti-edge deposition of the printed feature. © 2017 The Royal Society of Chemistry.
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    Effect of O2, N2 and H2 on annealing of pad printed high conductive Ag-Cu nano-alloy electrodes
    (Institute of Physics Publishing helen.craven@iop.org, 2018) Manjunath, G.; Anusha, P.; Salian, A.; Gupta, B.; Mandal, S.
    In this study, annealing of pad printed Ag-Cu based conducting ink was studied in oxidizing, inert and reducing atmosphere to verify its oxidation dependent conductivity. Ag-Cu manually was formulated adopting polyol method; where silver nitrate and copper nitrate serve as initial metal precursors. Polyvinylpyrrolidone (PVP), ethylene glycol and sodium borohydride act as a stabilizer, solvent and reducing agent respectively. The nanoalloys were with an average particle size ?48 ±15 nm, capped with polyvinylpyrrolidone to avoid agglomeration and stable in non-polar solvents. Formation of nanoalloy, Ag 90 wt%-Cu 10 wt%, was verified through a peak shift in UV-visible spectroscopy, found at 470 nm along with Nelson-Relay curve fitting and x-ray photoelectron spectroscopy study. The calculated lattice parameter of nanoalloy ?4.034 Å, was in between pure silver and copper. The crystallite size was calculated using Debye-Scherrer, Williamson-Hall isotropic strain model and Halder-Wagner method. Electrode patterns were printed on a glass substrate by pad printing and were annealed under O2, N2 and H2 atmosphere to study the oxidation kinetics of copper. A maximum conductivity of -6.6 ×;105 S m-1 was observed in inert atmosphere annealing as the conductivity is solely depends on the oxidation of copper; appears with uttermost Cu0 and least Cu2+ in x-ray photoelectron spectroscopy. High conductive space required between manually and dispersion ink can have a potential application as an electrode in printed electronics. Further refinement of size of the nanopaticles by polyol method could help to obtain the effect of quantum confinement. © 2018 IOP Publishing Ltd.