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ZnS thin films of different thicknesses were prepared by chemical bath deposition using thiourea and zinc acetate as S 2-and Zn 2+ source. The effect of film thickness on the optical and structural properties was studied. The optical absorption studies in the wavelength range 250-750 nm show that band gap energy of ZnS increases from 3⋅68-4⋅10 eV as thickness varied from 332-76 nm. The structural estimation shows variation in grain size from 6⋅9-17⋅8 nm with thickness. The thermoemf measurement indicates that films prepared by this method are of n-type.

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An attempt has been made to prepare polyvinyl alcohol (PVA) based proton conducting gel electrolytes in ammonium thiocyanate (NH 4 SCN) solution and to characterize them. XRD studies revealed that the entire gel sample are amorphous in nature with a broad peak at nearly 2θ=22 0 . Variation of conductivity of gel electrolyte with loading concentration of PVA has also been studied. It has been observed, as loading of PVA in 0.2 M electrolyte of NH 4 SCN+DMSO increases conductivity decreases. The conductivity of gel electrolytes exhibits liquid like nature at low polymer concentration while the behaviour is seen to be affected by the formation of PVA-NH 4 SCN complexes upon increase in polymer content beyond 2 g. Temperature dependence of ionic conductivity exhibits VTF and Arrhenius behaviour.

The present study reveals with study of electrical, thermal and optical band gap of polypyrrole filled PVC: PMMA thin films themoelctrets. Conducting polymer composites have attracted considerable interest in recent years because of their numeric applications in variety of electric and electronic devices. Polypyrrole has been regarded as one of the most studied conducting polymer because of its physical and electrical properties that have led to several applications such as solid state devices and electronics. The electrical conductivity of polypyrrole filled PVC: PMMA thermoelectrets have been studied. Electret effects in polymers can be produced by orientation of dipoles and /or trapping of charge carriers injected from electrodes as well as generated in the bulk of polymers. It has been shown by thermally stimulated discharge conductivity technique (TSDC) that the characteristics of electrets are very sensitive to the structure of electret forming materials. In this respect TSDC study of composite is likely to yield information about the extent of mixing between the components. Electrets prepared by composites have better charge storage capacity than the individual polymers. Measurements of TSD conductivity have been carried out at different polarizing fields. It has been observed that the conductivity of polypyrrole filled PVC: PMMA composite have been increased with increase in percentage of polypyrrole. The X-RD diffractogram reveals the amorphous nature of the films. The thermograms are plotted between logσ and temperature (10 3 /T).From the analysis of the absorption spectra the band gap of polypyrrole filled PVC: PMMA composite have been found to be lie in the range 1.8 eV to 3.3 eV. Thermal stability of polypyrrole filled PVC: PMMA was investigated by TGA/DSC. It is evident from the results that PPy filled polyblends are more stable.