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Microstructural characteristics and photoluminescence performance of nanograined thermally treated CeO2-TiO2 xerogels

Published online by Cambridge University Press:  03 March 2011

Amita Verma
Affiliation:
National Physical Laboratory, New Delhi 110012, India
A.K. Srivastava
Affiliation:
National Physical Laboratory, New Delhi 110012, India
N. Karar
Affiliation:
National Physical Laboratory, New Delhi 110012, India
Harish Chander
Affiliation:
National Physical Laboratory, New Delhi 110012, India
S.A. Agnihotry*
Affiliation:
National Physical Laboratory, New Delhi 110012, India
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

Nanostructured thermally treated xerogels have been synthesized using a sol-gel process involving cerium (Ce) chloride heptahydrate and titanium (Ti) propoxide mixed in different Ce:Ti molar ratios. Structural features of the xerogels have been correlated with their photoluminescence (PL) response. The crystallite sizes in the samples lie in the nanorange. The x-ray diffraction and transmission electron microscopy results have confirmed the coexistence of CeO2 and TiO2 nanocrystallites in these xerogels. In general, a decrease in the CeO2 crystallite size and an increase in the TiO2 crystallite size are observed in the xerogels as a function of Ti content. Scanning electron microscopy results have evidenced the evolution of ordered structure in the xerogels as a function of TiO2 content. Although both of the phases (CeO2 and TiO2) have exhibited PL in ultraviolet and visible regions, the major luminescence contribution has been made by the CeO2 phase. The largest sized CeO2 crystallites in 1:1 thermally treated xerogel have led to its highest PL response. PL emission in the xerogels is assigned to their nanocrystalline nature and oxygen vacancy-related defects.

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Articles
Copyright
Copyright © Materials Research Society 2007

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