Luminescence efficiency of aromatic carboxylates of europium and terbium when methylene bridges and nitro groups are present in the ligands
- 78 Downloads
We discuss the possibility of optimizing the brightness of luminescence for phenylcarboxylates, naphthylcarboxylates, and indolylcarboxylates of europium and terbium and their adducts with 1,10-phenanthroline and 2,2′-bipyridine by modifying the ligands. We have studied the efficiency of luminescence and luminescence excitation. We consider the effect of blocking energy transfer from the ligands to the Eu3+ and Tb3+ ions by methylene (-CH2-) bridges dividing the π-electron system of the ligands into two parts and by the electronacceptor nitro group (-NO2). We have analyzed the pathways for transfer and degradation of the excitation energy at 77 K and 300 K. From the phosphorescence spectra of gadolinium salts, we have determined the energies of the lowest excited triplet states of the ligands. We consider the effect of the relative positions of the triplet levels of the ligands and the excited levels of the Eu3+ and Tb3+ ions on the luminescence efficiency. We found channels for dissipation of the excitation energy via the ππ* and nπ* states of the aromatic system of the carboxylate and the NO2 group.
Key wordsEu3+ ion Tb3+ ion luminescence and luminescence excitation spectra luminescence efficiency aromatic carboxylates
Unable to display preview. Download preview PDF.
- 4.K. P. Zhuravlev and Yu. O. Yakovlev, Fiz. Tverd. Tela, 47, 1518–1521 (2005). [Physics of the Solid State, 47, 1579–1582 (2005).]Google Scholar
- 7.V. Tsaryuk, V. Zolin, J. Legendziewicz, J. Sokolnicki, and V. Kudryashova, in: Proceedings, Eleventh International Workshop on Inorganic and Organic Electroluminescence & 2002 International Conference on the Science and Technology of Emissive Displays and Lighting, Ghent University, Belgium (2002), pp. 165–168.Google Scholar
- 10.J.-F. Ma, Z.-S. Jin, and J.-Z. Ni, Acta Cryst., C50, 1008–1010 (1994).Google Scholar
- 12.M. A. Porai-Koshits, A. S. Antsyshkina, G. G. Sadikov, E. N. Lebedeva, S. S. Korovin, R. N. Shchelokov, and V. G. Lebedev, Zh. Neorg. Khim., 40, 748–756 (1995).Google Scholar
- 16.A. P. Suisalu, V. N. Zakharov, A. L. Kamyshnyi, and L. A. Aslanov, Zh. Eksp. Teor. Fiz., 98, 1330–1335 (1990).Google Scholar
- 17.R. N. Nurmukhametov, Absorption and Luminescence of Aromatic Compounds [in Russian], Khimiya, Moscow (1971).Google Scholar
- 18.L. M. Sverdlov, M. A. Kovner, and E. P. Krainov, Vibrational Spectra of Polyatomic Molecules [in Russian], Nauka, Moscow (1970), p. 328.Google Scholar
- 20.O. A. Reutov, Theoretical Principles of Organic Chemistry [in Russian], Mosk. Gos. Univ., Moscow (1964).Google Scholar
- 21.O. V. Sverdlova, Electronic Spectra in Organic Chemistry [in Russian], Khimiya, Leningrad (1985).Google Scholar