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Conclusion
In summary, five new terbium(III) complexes were synthe-
sized and characterized. Under UV irradiation these com-
plexes emitted intense characteristic peak of terbium ion at
546 nm, accountable for green luminescent color. The highest
intensity of electric dipole 5D4 → 7F5 transition indicated low
symmetric coordination environment around the terbium(III)
ion in complexes. It is noteworty that the emission spectra of
ternary complexes (C2-C5) revealed the stronger lumines-
cence intensity than the binary complex (C1). This enhance-
ment in intensity attributed to the efficient intramolecular en-
ergy transfer from lowest triplet level of ligands to lowest
excited level of terbium ion due to synergestic effect of
anciliary ligands. Thus, the results of photophysical properties
and high thermal stability demonstrated that these complexes
can be employed as one of green component in light emitting
materials and in display devices.
Acknowledgements The present work has been supported by Council of
Science and Industrial Research (CSIR) of India [09/382(0155)/2012-
EMR-I (Manju Bala)].
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