CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

lifetime values along with their relative contribution to the over all decay profile are shown in
Table 8. The lifetime values of the 5 D 4 level of Tb 3+ in the SbPO :Tb 3+
4 (2.5 at %) sample are
0.4 ms (τ 1 ) and 2.1 ms (τ 2 ) and the values corresponding to Ce 3+ co-doped SbPO :Tb 3+
4 (5 at%)
sample are 0.4 ms (τ ) and 2.4 ms (τ
1 2) with their relative contribution in the ratio ~ 22 : 78 for
3+
both the samples. In the case of SbPO4:Ce (2.5 at %),Tb 3+ (5 at %)-SiO 2 samples, the faster
component is absent.
1
Intensity (arb.units)
0.1
0.01
(a)
(b)
(c)
3 6 9 12
Time (ms)
15
Fig.73. Decay curves corresponding to the 5 D4 level of Tb 3+ ions from nanoribbons /
3+ 3+
nanoparticles of (a) SbPO 4 :Tb (5 at %), (b) SbPO 4 :Ce (2.5 at %),Tb 3+ (5 at %) and
3+
(c) SbPO4: Ce (2.5 at %), Tb 3+ (5 at %) dispersed in silica. The samples were
excited at 250 nm and emission was monitored at 544 nm.
Table 8. The lifetime values corresponding to the 5 3+ 3+
D 4 level of Tb ions in SbPO 4 :Ce , Tb 3+
nanoribbons/ nanoparticles along with the χ 2 values obtained from fitting. The
numbers in brackets give the relative concentration of each lifetime components.
Error in the lifetime values are within 5% as revealed by the duplicate
measurements
Sample name
Lifetime values
τ 1 (ms) τ 2 (ms) χ 2
Effective lifetime
(ms)
SbPO :Tb 3+ (5%) 0.4 (23%) 2.1 (77%) 1.1 3.09
4
3+
SbPO 4 :Ce (2.5%),Tb 3+ (5%) 0.4 (22%) 2.4 (78%) 1.2 3.28
3+
SbPO 4 :Ce (2.5%),Tb 3+ (5%) - SiO - 2.2(100%) 1.1 3.01
2
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