H. Nithya

Laser Raman and ac impedance spectroscopic studies of PVA: NH4NO3 polymer electrolyte.

Ion conducting polymer electrolyte PVA:NH(4)NO(3) has been prepared by solution casting technique and characterized using XRD, Raman and ac impedance spectroscopic analyses. The amorphous nature of the polymer films has been confirmed by XRD and Raman spectroscopy. An insight into the deconvoluted Raman peaks of upsilon(1) vibration of NO(3)(-) anion for the polymer electrolyte reveals the dominancy of ion aggregates at higher NH(4)NO(3) concentration. From the ac impedance studies, the highest ion conductivity at 303 K has been found to be 7.5x10(-3)Scm(-1) for 80PVA:20NH(4)NO(3). The conductivity of the polymer electrolytes has been found to depend on the degree of dissociation of the salt in the host polymer matrix. The combination of the above-mentioned analyses has proven worth while and in fact necessary in order to achieve better understanding of these complex systems.

Synthesis, micro-structural, and electrical analysis on lanthanum fluoride

Lanthanum fluoride nanorod and nanoparticles have been synthesized by a simple method with and without sonication, respectively. Thermogravimetric/differential thermal analysis confirms the sample formation at low temperature for the sonication-assisted sample than the directly prepared sample. The structure of the prepared lanthanum fluoride nanorods and nanoparticles has been analyzed by X-ray diffraction studies and the micro-structural properties have been studied using transmission electron microscopy. The transmission electron microscopic image reveals a capsule-like shape for the sample prepared under sonication. Ion conduction and conductivity analysis of the prepared nanorods and nanoparticles has been studied using AC impedance spectroscopy, and the ionic conductivity was found to increase by an order for the sample prepared with sonication.