Intermolecular Charge Transfer Induced Sensitization of Yb3+ in β-Diketone Coordination Compounds with Excellent Luminescence Efficiency
Trofim Polikovskiy, Daniil D. Shikin, Vladislav M. Korshunov, Victoria E. Gontcharenko, Mikhail T. Metlin, N. P. Datskevich, Meiirbek Islamov, V. O. Kompanets, С. В. Чекалин, Yu. А. Belousov, Ilya V. Taydakov
Abstract
Achieving high quantum yields for Yb3+ ion emission in complexes with organic ligands is a challenging task, as most Yb3+ complexes with such ligands typically exhibit efficiencies below 3.5%. Our research demonstrates that the introduction of heavy atom-containing ancillary ligands, such as TPPO or TPAO, along with the careful engineering of the main β-diketone ligand, can increase the luminescence efficiency up to 20-fold by the alteration of the energy migration pathway. It is demonstrated that the combination of two distinct organic ligands leads to the blockage of singlet–triplet intersystem crossing (ISC), alongside electronic energy transfer from β-diketone to Yb3+ ions through charge transfer states. The synthesized complexes exhibit quantum yields of 6.5% and 7.0% in the solid state, which places them at the top globally among this class of materials with simple non-deuterated and non-fluorinated ligands.