CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

The decay curves are found to be bi-exponential for all the samples. The corresponding life
times are 7.4 µs (30%) and 177 µs (70%) for Sb 2 O 3 nanorods synthesized in the presence of 5
at % Eu 3+ ions, 13 µs (49%) and 37 µs (51%) for europium oxide, prepared by the identical
procedure as that of Sb 2 O 3 nanorods and 46 µs (10%) and 238 µs(90%) for bulk Sb 2 O 3
synthesized in the presence of 5 at % Eu 3+ ions. The higher lifetime values corresponding to
the Eu 3+ present in Sb 2 O 3 nanorods and bulk Sb 2 O 3 compared to the europium hydroxide
support our previous inference that Eu 3+ ions are in a different environment in the Sb 2 O 3
sample and is not existing as separate europium hydroxide phase. In other words, Eu 3+ ions
are undergoing reaction with Sb 3+ to form europium antimony hydroxide compound.
To further substantiate the fact that Eu 3+ ions are not incorporated in Sb 2 O 3 lattice,
structural studies were carried out on Sb 2 O 3 samples prepared with different concentrations of
Eu 3+ ions and the results are described below. Figure 50(a) shows the FT-IR patterns of
Sb 2 O 3 nanorods prepared in the presence of Eu 3+ with concentrations 0, 2, 5 and 10 at %
(with respect to Sb 3+ ions) over the range of ~ 270 to 1200 cm -1 . Sb 2 O 3 nanorods prepared
both in presence and in absence of Eu 3+ ions are characterized by mainly 5 peaks, with
identical peak maximum and line shape. It may be noted that these positions agree well with
that of the bulk Sb 2 O 3 as reported by Cody, et al. [208] and Deng, et al. [65].
Absorbance (Arb. units)
1.0
0.8
0.6
0.4
0.2
0.0
10 % Eu 3+
5 % Eu 3+
2 % Eu 3+
undoped
400 600 800 1000
Wavenumber (cm -1 )
200 400 600
Wavenumber (cm -1 )
(a)
(b)
Fig.50. FT-IR patterns (a) and Raman Spectra (b) of Sb 2 O 3 nanorods prepared in presence of
different Eu 3+ concentrations.
Intensty (arb. units)
1.0
0.8
0.6
0.4
0.2
0.0
10% Eu 3+
undoped
5% Eu 3+
97