Browsing by Author "S.K. Kulkarni"

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Confinement of zinc oxide nanoparticles in ordered mesoporous silica MCM-41
(2012) P.B. Lihitkar; Samuel Violet; Mandar Shirolkar; Jai Singh; O.N. Srivastava; R.H. Naik; S.K. Kulkarni
Mesoporous silica (MS) and zinc loaded MS composites have been synthesized and characterized using high resolution transmission electron microscopy, X-ray diffraction, UV-visible spectroscopy, photoluminescence spectroscopy, N 2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Thermal treatment of the zinc loaded MS composite lead to the formation of ZnO-MS composite. The well ordered uniform pore structure of MS (pore size ∼3.4 nm) is found to remain stable even after 30% Zn loading albeit decrease in the pore size 1.2 nm indicates the formation of ZnO inside the pores. © 2012 Elsevier B.V. All rights reserved.
Optical investigations of interaction between zinc tetra phenyl porphyrin and CdSe nanoparticles
(2009) N.B. Lihitkar; S.B. Singh; Jai Singh; O.N. Srivastava; R.H. Naik; S.K. Kulkarni
Interactions between nanoparticles of zinc tetra phenyl porphyrin (ZnTPP) with CdSe nanoparticles in dimethyl sulphoxide solvent have been investigated. A ZnTPP-CdSe complex was formed which showed substantial changes in the UV-Vis absorption spectra in the presence of CdSe. Fluorescence measurements showed an interesting behavior at low as well as high concentrations of CdSe. When low concentrations of CdSe nanoparticles were added to the ZnTPP nanoparticles solution, besides two fluorescence bands due to ZnTPP nanoparticles, an intense new band appeared. On the other hand at high concentrations of CdSe one of the fluorescence band of ZnTPP at ∼604 nm increased. © 2009.