CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

comparison, Eu 3+ ions alone in water is subjected to urea treatment as described above for
two hours and XRD pattern of the precipitate is shown in Fig.25 (d). The pattern matches
well with that of crystalline europium hydroxide carbonate (PC-PDF-No: 43-0603). These
results further confirm that ion exchange process is not responsible for the collapse of the
layered structure of GaOOH instead Eu 3+ incorporation at the inter layer spacing and its
reaction with OH groups at the inter layer spacing may be a reason for amorphisation. Such
amorphisation process is also expected to have significant effect on the luminescence
properties of lanthanide ions and hence detailed luminescence studies were carried out for
these samples and are described below.
Intensity(arb.units)
Eu 2
O(CO 3
) 2
.H 2
O
(d)
(c)
(b)
GaOOH
(a)
20 30 40 50
2 θ /°
Fig.25. XRD patterns corresponding to GaOOH nanorods treated with aqueous solution of
Eu 3+ ion in presence of urea ~100°C for (a) 0 minutes (b) 30 minutes (c) 2 hours. The
corresponding pattern obtained only with Eu 3+ ions in the absence of GaOOH is
shown in Fig.25 (d).
Figure 26 shows the emission and excitation spectrum of as prepared GaOOH
nanorods synthesized in the absence of lanthanide ions (Eu 3+ ). The emission spectrum
matches well with that reported by Huang and Yeh [182]. Emission spectrum is characterized
by a peak around 435 nm, which is arising from the electronic transition involving Ga-O
69