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Coexistence of Förster and Dexter Energy Transfer Pathways from an Antenna Ligand to Lanthanide Ion in Trivalent Europium Complexes through Phosphine-Oxide Bridges

preprint
submitted on 13.04.2020 and posted on 15.04.2020 by Shiori Miyazaki, Kiyoshi Miyata, Haruna Sakamoto, Fumiya Suzue, Yuichi Kitagawa, Yasuchika Hasegawa, Ken Onda

Trivalent europium (Eu3+) complexes are attractive materials for luminescence applications if energy transfer from antenna ligands to the lanthanide ion is efficient. However, the microscopic mechanisms of the transfer remain elusive and fundamental physical chemistry questions still require answers. We track the energy transfer processes in a luminescent complex Eu(hfa)3(DPPTO)2 (hfa: hexafluoroacetylacetonate, DPPTO: 2-diphenylphosphoryltriphenylene) using time-resolved photoluminescence spectroscopy. In addition to the conventional Dexter-type energy transfer pathway through the T1 state of the ligands, we discovered the Forster energy transfer pathway from the S1 of the DPPTO ligands to the 5D1 state of Eu3+ through the weak electronic interaction of a phosphine-oxide bridge. The short timescale of the energy transfer (16 ns, 127 ns) results in its high quantum yield. The coexistence of the distinct energy transfer pathways from a single chromophore is important for establishing design strategies of luminescent complexes.

History

Email Address of Submitting Author

konda@chem.kyushu-univ.jp

Institution

Kyushu University

Country

Japan

ORCID For Submitting Author

0000-0003-1724-2009

Declaration of Conflict of Interest

No conflict of interest

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