CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

5 D 0 → 7 F 2 to 5 D 0 → 7 F 1 transition) is calculated from the emission spectrum and found to be
1.14. The excitation spectrum corresponding to 616 nm emission is shown as an inset in
Fig.64 (a). In addition to the sharp peaks characteristic of intra 4f transitions of Eu 3+ ions, a
broad asymmetric peak centered on 250 nm with a shoulder around 220 nm is observed in the
excitation spectrum. Based on detailed luminescence studies on Eu 3+ doped and un-doped
SbPO 4 nanoparticles/ nanoribbons, the broad peak centered on 250 nm has been attributed to
the Eu-O charge transfer process and the weak shoulder around 220 nm to the host
absorption. Eu 3+ emission has been observed from these samples after excitation at 250 and
220 nm indicating that there is energy transfer from the host to Eu 3+ ions.
Intensity(arb. units)
20
10
0
550 600 650 700
150
100
50
0
(a)
(b)
5
D4
7
F6
5
D0
7
F1
5
D0
7
F2
400
360
200 250 300 350
400
200
5
D4
7
F4
5
D4
7
F5
Eu-O (CT)
(~ 220 nm)
4f-5d (Tb 3+ )
(~ 220 nm)
200 300 400
500 600 700
wavelength(nm)
Fig.64. Emission spectrum of (a) SbPO 4 :Eu , (b) SbPO 4:Tb
nanoparticles/ nanoribbons
obtained after 220nm excitation. Insets show corresponding excitation spectrum
monitored at 616 and 545 nm emission.
For Tb
5
D4
7
F3
3+ 3+
3+ 3+
doped SbPO 4 nanoparticles/ nanoribbons (Fig.64 (b)), strong Tb emission
characteristic of 5 D 7 5 7 5 7 5
4 Æ F 3 , D 4 Æ F 4 , D 4 Æ F and D Æ 7 F transitions have been
7
F0
5
G6
7
F6
5
G5
5 4 6
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