AuxAgy@ZrO2 redispersible core-shell nanoparticles were prepared by a single step synthesis using the dimethyl formamide (DMF) reduction procedure. The material is stable for extended periods of time. The core-shell alloy nanoparticles were characterized by UV-vis spectroscopy, transmission electron microscopy, X-ray diffraction, differential scanning calorimetry and cyclic voltammetry. The as prepared particles are nanocrystalline in nature, but they give well-defined diffraction patterns upon heating to 100°C for 8 h. The average diameter of the core is ∼35 nm and typical shell thickness is 2-3 nm. The materials show interesting reactivity with halocarbons as in the case of naked metal nanoparticles, which vary with the composition of the alloy. Our experiments show that oxide-protected alloy nanoparticles are excellent optical limiters in the nanosecond regime. Optical nonlinearity of these systems has been investigated in detail and a qualitative model has been proposed. To the best of our knowledge, this is the first report of nanoparticles having a true alloy core and an oxide shell. © 2004 Elsevier B.V. All rights reserved.
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A. S. Nair, Suryanarayanan, V., Pradeep, T., Thomas, J., Anija, M., and Philip, R., “AuxAgy@ZrO2 core-shell nanoparticles: Synthesis, characterization, reactivity and optical limiting”, Materials Science and Engineering B: Solid-State Materials for Advanced Technology, vol. 117, pp. 173-182, 2005.