Conducting polymer is a very interesting and scientifically as well astechnologically important class of polymer. This research work aims togain an insight into the monomer level processes and mechanism ofelectropolymerization of conducting polymer (CP) so as to control theporosity and morphology and standardize various parameters for obtainingbetter quality CP films. Another objective is to study the effects ofheavy ion irradiation on CP electrodes and to understand the interactionof the fast ions with the polymer film. Polyaniline, polypyrrole andpoly(3-methylthiophene) CP films doped with different dopants have beeninvestigated. Electrochemical synthesis of CP films was carried out in three electrodesingle compartment electrochemical cell on indium doped tin oxide (ITO)coated glass substrates. These CP films were irradiated with swift heavyion (SHI) beam of 160 MeV Ni12+ and 120 MeV Si9+ to investigate theeffect of irradiation on CP electrodes. Cyclic voltammetry, dcconductivity, XRD, SEM, UV-Vis and FTIR studies were carried out forcharacterization of the CP films before and after irradiation. Theperformance of the CP films as electrodes has also been investigated byfabricating supercapacitors with unirradiated and irradiated CP films aselectrodes.The electrochemical polymerization of CP produces better quality films inthe potentiodynamic mode as compared to potentiostatic mode. The dcconductivity of the conducting polymer films has been observed to bedependent on the type of dopant ions. The scanning electron microscopy ofthe conducting polymer films shows that the potentiodynamic polymerizationmethod produced films with better surface morphology as compared to thoseby the potentiostatic method. Grain growth and densification of thepolymer film surface have been observed upon SHI irradiation. The UV-Visstudy showed that the polymer absorbing at higher wavelength exhibitsbetter conductivity. Increase in carrier absorption intensities with shiftof absorption peaks towards higher wavelength were observed in the UV-Visspectra of the irradiated CP films indicating lowering of band gap andincrease in electrical conductivity. The dopant ion interaction absorptionpeaks in the FTIR spectra confirmed the presence of the dopants in the CPfilms deposited by electrochemical polymerization and also afterirradiation. The XRD patterns of the unirradiated CP films showedsemi-crystalline nature of the films with increase in degree ofcrystallinity upon SHI irradiation.Solid state all-polymer redox supercapacitors fabricated using CP films aselectrodes and PVDF-HFP-PMMA gel polymer electrolyte showed goodcapacitive behaviour with capacitance on the order of 200-250 F/gm andCoulombic efficiency of about 90-96%. Stability tests up to 10,000charge-discharge cycles showed that the supercapacitors fabricated byusing SHI irradiated CP films exhibit slightly less capacitance andCoulombic efficiency but markedly improved electrochemical stability. Avery small decrease in internal resistance of the supercapacitors is foundafter SHI irradiation. A decrease in total charge-discharge time has alsobeen observed for supercapacitors with SHI irradiated electrodes.

This work concerns the interplay of strong correlation and disorder in two dimension at half-filling using 2D t-t’ Hubbard modelwith deterministic disorder. Inclusion of t’ leads to a metallic phase at half-filling below a certain critical value of U. Above this critical value Uc correlation favours Neel ordering while disorder alone leads to double occupancy over the lower energy site. This competition leads to the emergence of a metallic phase, which has been quantified by the calculation of Kubo conductivity, gap at half-filling, density of states, spin order parameter and bandwidth calculation. The deterministic disorder follows a Fibonacci sequence. We have also studied the effect of reducing the dimension of the system. Calculation for both zero and finite temperatures have been done.

Photoemision spectroscopic results obtained on (a)CaB6 and LaB6(b)PdAg(100) surface allys (c) Ta/Si(100) and (d) Ta nano-structures willbe discussed. CaB6 exhibits surprisingly a ferromagnetic behavior withoutmagnetic ions present. Origin of the FM behavior observed in CaB6 wasinvestigated using high resolution photoemission studies. A pseudogapformation has been observed in LaB6 which explains the low temperatureanomalies exhibited by LaB6. Core level chemical shifts observed onPdAg(100) ordered surface alloys will be discussed against the core levelchemical shifts observed for random bulk PdAg alloys. Thermal stability ofTa2O5 deposited on Si(100) was investigated using high energyphotoemission technique. The effect of in-situ annealing on the corelevels of Ta, Si and O will be discussed briefly. Ta nano-structures havebeen prepared by sputtering Ta foil in-situ in XPS machine using argon ionsputtering. Ta 4f exhibited a surface core level shift of 0.5 eV with anegligible bulk Ta 4f intensity. High intensity of the surface core levelindicates nano-structureformation and AFM topography shows nano-structure formation.