• P P PRADYUMNAN

      Articles written in Bulletin of Materials Science

    • Structural and magnetic studies on copper succinate dihydrate single crystals

      M P BINITHA P P PRADYUMNAN

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      Single crystals of copper succinate dihydrate were grown in silica gel by slow diffusion of copper chloride tosodium metasilicate gel impregnated with succinic acid. The grown crystal was subjected to single crystal X-ray diffractionstudies. In its structure each copper atom is penta co-ordinated to oxygen atoms of four succinate oxygens and oxygenof co-ordinated water molecule. The four bis-bidendate succinate anions form syn–syn bridges among two copper atomsto form a polymeric two-dimensional chain. From room temperature vibrating sample magnetometer (VSM) studies themagnetic moment of the material is calculated as 1.35 Bohr magneton (BM), indicating antiferromagnetic interaction betweencopper atoms and can be explained as due to the orbital overlap of the bridging ligand and the two copper atoms in syn-synorientation. A strong bonding of the magnetic orbital of equatorially oriented Cu atom on both sides of the exchange pathway(Cu–O-C-O–Cu) leads to the anti-ferromagnetic interaction.

    • Photoluminescence quenching and photocatalytic enhancement of Pr-doped ZnO nanocrystals

      N K DIVYA P P PRADYUMNAN

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      This work reports the synthesis of novel praseodymium (Pr)-doped ZnO nanocrystals with excellent photocatalyticactivity through modified solid-state reaction route. The impacts of doping on the wurtzite hexagonal structureare analysed with X-ray diffraction (XRD) and Raman spectroscopy. The production of defect levels and the formation ofUrbach energy within the system are confirmed using photoluminescence (PL) techniques and UV/Vis diffuse reflectancespectroscopy, respectively. The linear relationship between Urbach energy and band gap energy is elucidated from UV/Visspectroscopy analysis. The changes happened to morphology by doping were tackled using scanning electron microscopy(SEM). The concentration quenching effect of PL emission with Pr doping is explained in detail. A three-fold enhancementin the photocatalytic activity was achieved with optimum Pr incorporation in ZnO. This work successfully correlated PLquenching and enhanced photocatalytic activity with the defect production happened in ZnO system on Pr doping. Thepractical applicability of the photocatalyst was confirmed with a stability test.

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