Aqueous Synthesis and Characterization of CdTe@Co(OH)₂         (core-shell) Composite Nanoparticles

M. S. Abd El-sadek*^1,2, J. Ram kumar² and S. Moorthy Babu*²

¹Physics Department, Faculty of Science, South Valley University, Qena-EGYPT.

²Crystal Growth Centre, Anna University, Chennai-25, INDIA.

^*1 el_sadek_99@yahoo.com, ^*2 babu@annauniv.edu

ABSTRACT

Multi-functional CdTe@Co(OH)₂ core-shell nanoparticles were synthesized in aqueous solution by a seed-mediated growth approach. Initially, the luminescent CdTe nanocrystals were synthesized with bi-functional molecule mercaptoacetic acid as a stabilizer. The Co²⁺ was added to CdTe nanocrystals aqueous solution and slowly hydrolyzed to deposit a layer of hydroxide (Co(OH)₂) onto the luminescent CdTe nanocrysals (as a core) in the presence of stabilizer at pH ?? 11.2. The effect of refluxing time and the concentration of Co²⁺ on the preparation of these samples were measured using UV-Visible absorption and photoluminescence analysis. The UV-Visible absorption and photoluminescence results show that the band edge emission is redshifted by increasing the refluxing time and the thickness of Co(OH)₂ shell. The synthesized CdTe@Co(OH)₂ core-shell nanoparticles were characterized with XRD, EDAX, FT-IR and thermal analysis. The results show that as-prepared nanoparticles with core/shell structure exhibited certain optical properties. These composite nanoparticles have some potential applications, such as magnetic resonance (MR)/optical imaging, being used as catalyst and magnetic-optical materials.

Keywords: Qauantum dots, CdTe nanocrystals, Mercaptoacetic Acid, Optical and

                    Magnetic properties, FT-IR spectroscopy.

* Corresponding Author:-   M. S. Abd El-sadek

Crystal Growth Centre,

Anna University,

Chennai-25,

INDIA.

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