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Indian Journal of Pure & Applied Physics (IJPAP) >
IJPAP Vol.47 [2009] >
IJPAP Vol.47(11) [November 2009] >
| Title: | Luminescence efficiency of Eu+3 in Y2O3: The effect of reduction of particle size and incorporation of trace hetero-cations in the Y2O3 lattice |
| Authors: | Nayak, A
Goswami, K
Ghos, A
Debnath, R |
| Keywords: | Y2O3:Eu+3 red phosphor
Luminescence efficiency
Host’s polarity
Nanocrystals
Hydration
Non-radiative loss |
| Issue Date: | Nov-2009 |
| Publisher: | CSIR |
| Abstract: | The effect of
incorporation of trace (Al+3, B+3) in the Y2O3
lattice on the luminescence efficiency of Y2O3:Eu+3
red phosphor has been investigated. It is observed that such
incorporation causes an enhancement of 5D0→7F2
red luminescence efficiency as well as the associated excitation efficiency of
Eu+3. It is concluded that there occurs a change in the polarity of
the host rather than the site symmetry of Eu+3 due to incorporation
of the hetero cations. Calculation of the Judd-Ofelt parameters gives similar
results. In another study, to observe the effect of reduction of particle size
on the luminescence efficiency of the Y2O3:Eu+3,
the change in luminescence efficiency of the phosphor with the reduction particle size and the stability of the
different efficiencies with the elapse of time have been investigated.
The samples with particle size below 100 nm showed a significant loss in
luminescence efficiency and a change in their excitation profile with time. IR
studies showed that although the
freshly prepared samples were almost free from contaminated water, on ageing in
air at room temperature, they absorb the latter. A phenomenon of
hydration induced coupling of the excitonic state of Y2O3 with one of its Fu modes,
has been detected in the case of the aged samples which susequently introduces
newer non-radiative channels in the system causing a decrease in the
luminescence efficiency of the phosphor. Because of larger surface to volume
ratio, the effect is most pronounced in nanocrystalline samples. |
| Page(s): | 775-781 |
| ISSN: | 0975-1041 (Online); 0019-5596 (Print) |
| Source: | IJPAP Vol.47(11) [November 2009]
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