CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

3+
4.4.7 Luminescence studies on Dy doped BiPO 4 nanorods: Figure 88 (a) shows the
3+
emission spectrum from BiPO4 nanorods doped with 2.5 at % of Dy obtained after
excitation at 350 nm. It consists of two peaks at 478, 573 nm corresponding to 4 F 9/2 → 6 H 15/2
and 4 F 9/2 → 6 H13/2 transitions, respectively of Dy 3+ ion in BiPO4 nanorods. The corresponding
excitation spectra monitored at 573 nm emission is shown in Fig.88 (b). It consists of a broad
band centered at 255 nm along with sharp transitions above 300 nm. The broad band at 255
nm is due to host absorption. Observation of host absorption peak while monitoring Dy 3+
emission confirms the energy transfer from host to Dy 3+ ions. The less intense sharp peaks in
the excitation spectrum are arising due to f-f transitions of Dy 3+ ion present in the lattice. The
decay curve corresponding to 4 F level of Dy 3+
9/2 ion is shown in Fig.88 (c). It is a biexponential
in nature with lifetime component 22 ms (15%) and 793 ms (85%).
400 4 F 9/2
6 H 13/2
800
Intensity (arb.units)
300
200
100
4 F 9/2
6 H 15/2
λ exc
= 350 nm
Intensity (arb.units)
600
400
200
λ em
= 573 nm
0
400 450 500 550 600 650 700
Wavelength (nm)
(a)
0
200 250 300 350 400
wavelenght (nm)
(b)
Intensity (arb.units)
100
10
λ exc
= 350 and λ em
= 573 nm
1
0 2 4 6
Time (ms)
(c)
Fig.88 (a) Emission spectrum obtained after excitation at 350 nm (b) excitation spectra
monitored at 573 nm emission and (c) decay curve corresponding to 4 F 9/2 level of
Dy 3+ ion in BiPO :Dy 3+ nanorods.
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