Phonon confinement effect in mixed Sn-Ir oxide nanocrystals

SALIS, MARCELLO;RICCI, PIER CARLO;CAPPELLETTI G;ANEDDA, ALBERTO

2010-01-01

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Abstract

Raman spectra in Sn(1-x)Ir(x)O(2) (x <= 0.15) nanocrystals were investigated to estimate and separate the contributions of phonon confinement and composition effects. To this end, the Raman frequency of the A(1g) bulk-mode of pure SnO(2) and It-mixed nanocrystals has been studied in details as a function of the size and the Iridium concentration. As an initial working hypothesis it was assumed a linear dependence of the Raman shift as a function of the Iridium molar concentration, while a quadratic expansion of the dispersion curve has been utilised in the phonon confinement effect. Comparison of predicted and experimental results is reported. (C) 2010 Elsevier B.V. All rights reserved.