ESTONIAN ACADEMY
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eesti teaduste
akadeemia kirjastus
PUBLISHED
SINCE 1952
 
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proceedings
of the estonian academy of sciences
ISSN 1736-7530 (Electronic)
ISSN 1736-6046 (Print)
Impact Factor (2020): 1.045

Study of thermal and optical properties of dibenzoylmethane Eu(III) organic complexes; pp. 493–500

Full article in PDF format | https://doi.org/10.3176/proc.2017.4.11

Authors
Ilze Malina, Nikolajs Juhnevics, Valdis Kampars

Abstract

Two Europium(III) organic complexes (ternary complex Eu(DBM)3(PHEN) and tetrakis complex [Eu(DBM)4]N(Et)4, where DBM is dibenzoylmethane and PHEN is 1,10-phenantroline) were synthesized and their structures proven with 1H-NMR spectroscopy, elemental analysis, FT-IR and mass spectroscopy. Their photophysical properties have been investigated in solution, solid-state and in poly-N-vinylcarbazole (PVK) films varying complex composition from 1 to 15 wt%. Both complexes exhibit intense UV light absorption and bright red-light emission with maximum wave length at 612 nm. It was shown that tetrakis complex in solution, solid-state and PVK films have enhanced photoluminescence properties compared to ternary complex due to four DBM molecules in Eu3+ coordination sphere, which leads to more effective excited energy transfer to Eu3+ ion. In THF solutions both complexes are characterized with low photoluminescence quantum yields (4% and 6%), in PVK films – moderate quantum yields (14–48%), but in solid state with high quantum yields (56% and 75%). Thermal properties for pure complexes and their PVK films were studied with thermogravimetric analysis. Both complexes exhibit high thermal degradation temperatures of 304 °C for ternary and 267 °C for tetrakis complex, but their PVK films show even higher degradation temperature (over 370 °C).


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