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A ternary system composed of Tb(DBM)3Phen (TbDP), Eu(DBM)3Phen (EuDP), and poly(N-vinylcarbazole) (PVK) was prepared with good thermal stability and the photoluminescence (PL) was studied. By comparing their emissions, it was found that energy transfer exists from PVK to lanthanide complexes in the ternary system. It also was found that the lifetime of 5D0 of Eu3+ in the ternary system is longer than that of the binary system of EuDP and PVK, but the lifetime of 5D4 of Tb3+ in the ternary system is shorter than that of the binary system of TbDP and PVK, showing evidence of energy transfer from TbDP to EuDP. Temperature-dependent PL spectra of the ternary system from 9 to 300 K further showed there is a change in energy transfer efficiencies from Tb3+ ions to Eu3+ ions at different temperature ranges, which not only is more evidence of energy transfer but also can be used as a temperature detector or a thermal-sensitive probe of a optical fiber sensor. [ABSTRACT FROM AUTHOR]

Abstract: Photoluminescence of Eu(TTA)3DPBT (TTA=thenoyltrifluoro-acetonate DPBT=2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine) in toluene and PMMA thin film are measured with excitation at 350 and 404nm, respectively, and analyzed using Judd–Ofelt theory. Under excitation at 350nm, it is found that Eu(TTA)3DPBT in toluene has a larger Ω 2 value (14.33×10−20 cm2) than that (12.70×10−20 cm2) of Eu(TTA)3Phen (Phen=1,10-phenanthroline) in the same solvent, and has a smaller Ω 2 value (12.70×10−20 cm2) in PMMA than that (Ω 2=14.09×10−20 cm2) of Eu(TTA)3Phen in PMMA. At the same time, it can be seen that under excitation at 350nm Ω 2 value of Eu(TTA)3DPBT in toluene is larger than that in PMMA. Excited by 404nm, Ω 2 of Eu(TTA)3DPBT obtained in toluene and in PMMA are the same as that excited at 350nm. The transition probability (A), emission cross-section (σ) and the fluorescence branching ratio (β) are also evaluated. The lifetime of 5D0 metastable state is measured on 350 and 404nm excitation, respectively. For the former situation, it is 455μs in toluene and 640μs in PMMA, for the latter it is 460μs in toluene and 664μs in PMMA. By comparing absorptions with excitations, it can be found that DPBT is more efficient than TTA as an energy donor. Phosphorescence spectra are also measured to estimate the lowest triplet level and analyze the energy transfer for DPBT and TTA, from which it is found that the energy transfer from TTA to DPBT occurs in the luminescent process. [Copyright &y& Elsevier]