CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

As prepared undoped Sb 2 O 3 sample is characterised by broad asymmetric peak
centered around 3440 cm -1 . This has been attributed to the stretching vibrations of the OH
groups present on the surface of the Sb 2 O 3 nanorods. In addition, sharp peaks in the form of
a triplet associated with the –C-H stretching vibrations of the isopropanol molecule (as a
stabilizing ligand on the surface of Sb 2 O 3 ) is also observed around 2920 cm -1 . For the sample
with 10% Eu 3+ , this OH band is shifted to 3398 cm -1 , together with a considerable increase in
the asymmetry towards lower wave numbers. This suggests the possibility of the formation of
europium antimony hydroxide compound in the Eu 3+ containing Sb 2 O 3 nanorods which is
further supported by the luminescence results discussed above.
To understand the nature of compound formation taking place between Sb 3+ and Eu 3+
ions, stoichiometric concentrations of Sb 3+ and Eu 3+ ions (Sb 3+ : Eu 3+ ratio is maintained at 5:
3, as Sb 5 Eu 3 O 12 is the only phase formed between Sb 3+ and Eu 3+ reported in the literature)
were allowed to react under same experimental conditions as adopted for the synthesis of
Sb 2 O 3 nanorods. Figure 52 shows the XRD patterns of the reaction product obtained by the
reaction between Sb 3+ and Eu 3+ ions along with the same product subjected to heat treatments
at 500 and 900°C. As prepared and 500°C heated samples are amorphous (Fig.52 (a and b)),
however on heating to 900°C, hydrated Sb 2 O 5 phase along with HSb 3 O 8 and Eu 2 O 3
are
formed as can be seen from the XRD patterns shown in Fig.52 (c). If there is no interaction
between Sb 3+ and Eu 3+ ions, as prepared sample should contain highly crystalline Sb 2 O 3
nanorods and that should have reflected in the XRD pattern shown in Fig.52 (a). This is not
observed in the present study further supporting the antimony europium hydroxide compound
formation. On heating the compound, antimony europium hydroxide, result in its
decomposition or oxidation to form HSb 3 O 8 , hydrated Sb 2 O 5 and Eu 2 O 3 .
Figure 53 shows the emission spectrum and decay curves from the hydrated europium
antimony oxide heated at different temperatures. As prepared and 500°C heated samples gave
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