Electroluminescent devices based on rare-earth tetrakis β-diketonate complexes
In this paper the synthesis, photoluminescence and electroluminescence investigation of the novel tetrakis β-diketonate of rare-earth complexes such as, M[Eu(dbm) 4] and M[Tb(acac) 4] with a variety of cationic ligands, M = Li +, Na + and K + have been investigated. The emission spectra of the Eu 3+...
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Published in | Thin solid films Vol. 517; no. 3; pp. 1096 - 1100 |
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Main Authors | , , , , , , |
Format | Journal Article Conference Proceeding |
Language | English |
Published |
Amsterdam
Elsevier B.V
01.12.2008
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | In this paper the synthesis, photoluminescence and electroluminescence investigation of the novel tetrakis β-diketonate of rare-earth complexes such as, M[Eu(dbm)
4] and M[Tb(acac)
4] with a variety of cationic ligands, M
=
Li
+, Na
+ and K
+ have been investigated. The emission spectra of the Eu
3+ and Tb
3+ complexes displayed characteristic narrow bands arising from intraconfigurational transitions of trivalent rare-earth ions and exhibited red color emission for the Eu
3+ ion (
5D
0→
7F
J
,
J
=
0–6) and green for the Tb
3+ ion (
5D
4→
7F
J
,
J
=
6–0). The lack of the broaden emission bands arising from the ligands suggests the efficient intramolecular energy transfer from the dbm and acac ligands to Eu
3+ and Tb
3+ ions, respectively. In accordance to the expected, the values of PL quantum efficiency (
η) of the emitting
5D
0 state of the tetrakis(β-diketonate) complexes of Eu
3+ were higher compared with those tris-complexes. Therefore, organic electroluminescent (EL) devices were fabricated with the structure as follows: indium tin oxide (ITO)/hole transport layer (HTL) NPB or MTCD/emitter layer M[RE(β-diketonate)
4] complexes)/Aluminum (Al). All the films were deposited by thermal evaporation carried out in a high vacuum environment system. The OLED light emission was independent of driving voltage, indicating that the combination of charge carriers generates excitons within the M[RE(β-diketonate)
4] layers, and the energy is efficiently transferred to RE
3+ ion. As a best result, a pure red and green electroluminescent emission was observed from the Eu
3+ and Tb
3+ devices, confirmed by (
X,
Y) color coordinates. |
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ISSN: | 0040-6090 1879-2731 |
DOI: | 10.1016/j.tsf.2008.06.012 |