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Somerset East, South Africa

Mongwaketsi N.,NANOAFNET | Mongwaketsi N.,South African Council for Scientific and Industrial Research | Khamlich S.,NANOAFNET | Pranaitis M.,CNRS Angers Institute of Molecular Science and Technology | And 5 more authors.
Materials Chemistry and Physics | Year: 2012

The non-linear optical properties of porphyrin nanorods were studied using Z-scan, Second and Third harmonic generation techniques. We investigated in details the heteroaggregate behaviour formation of [H 4TPPS 4] 2- and [SnTPyP] 2+ mixture by means of the UV-VIS spectroscopy and aggregates structure and morphology by transmission electron microscopy. The porphyrin nanorods under investigation were synthesized by self assembly and molecular recognition method. They have been optimized in view of future application in the construction of the light harvesting system. The focus of this study was geared towards understanding the influence of the type of solvent used on these porphyrins nanorods using spectroscopic and microscopic techniques. © 2012 Elsevier B.V. All rights reserved. Source

Sone B.T.,NANOAFNET | Sone B.T.,University of the Western Cape | Benoit R.,CNRS Center for Research on Divided Matter | Zongo S.,NANOAFNET | And 2 more authors.
Materials Chemistry and Physics | Year: 2012

In an autoclave partly-filled with water wherein a V metal strip is placed 70° to the horizontal we observed that VO 2 nanorods and exfoliated microspheres were generally grown on the portion of the strip above the water surface while parallelepiped-like structures were generally grown on the portion below. XRD, HRTEM, showed that VO 2 structures produced were monoclinic and base centred in crystal structure. FT-IR, Raman Spectroscopy and XPS suggested that V metal was oxidized by hydrothermal synthesis in water to yield two oxides, V 2O 3, and VO 2, with VO 2 forming the bulk of the product. A time-based investigation of the synthesis of VO 2 micro-nanostructures on V metal by hydrothermal synthesis suggests that the nucleation and growth of VO 2/V 2O 3 micro-nanostructures is temperature-controlled and not kinetics/diffusion-controlled, with optimal temperatures for the synthesis being in the vicinity of 185-190 °C and growth of these oxides taking place in 2 h as opposed to 7 days in previously reported work [L. Jiang et al., VO 2 rods with a rectangular cross-section, Journal of Crystal Growth, 310 (2008) 4301-4304]. We propose here a mechanism for the growth of the two types of micro/nanorods above water and the parallelepiped-like structures grown on V metal found below the water level. © 2012 Elsevier B.V. All rights reserved. Source

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