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Solvent-dependent Sensitization and Photophysical Behavior of IrIII-EuIII Bimetallic Complexes
Felipe S M Canisares1,2, Vytor C Oliveira3,4, Alessandro B S Garcia1
1Institute of Chemistry, São Paulo State University (UNESP), Araraquara, SP, Brazil.
Journal of Fluorescence
|August 11, 2026
Summary
Solvent properties significantly impact energy transfer in heterobimetallic complexes, with polar, coordinating solvents enhancing iridium-to-europium sensitization up to 90%. Protic solvents, however, quench europium emission despite efficient energy transfer.
Area of Science:
- Coordination Chemistry
- Photophysics
- Materials Science
Background:
- Heterobimetallic complexes combining d- and f-block metals offer unique photophysical properties.
- Europium (EuIII) sensitization is crucial for developing luminescent materials, but efficiency is often solvent-dependent.
- Understanding solvent effects is key to optimizing energy transfer (ET) in these systems.
Purpose of the Study:
- To investigate the influence of solvent characteristics on the photophysical properties of a heterobimetallic Iridium(III)-Europium(III) complex.
- To elucidate the factors governing Europium(III) sensitization via energy transfer from the Iridium(III) center.
- To provide insights into designing efficient d-f heterobimetallic luminescent systems.
Main Methods:
- Steady-state and time-resolved luminescence spectroscopy were employed.
- Solvents with varying polarity, coordinating ability, and vibrational properties were utilized.
- Energy transfer rate constants (kET) and efficiencies (ηET) were estimated using luminescence lifetimes.
Main Results:
- Solvent polarity and coordinating ability positively correlated with IrIII→EuIII energy transfer rates and efficiencies.
- Optimal conditions (e.g., DMSO) yielded kET up to 2.6 × 10^7 s^-1 and ηET up to 90%.
- Protic solvents (containing O-H oscillators) significantly quenched EuIII emission, while oxygen had a minor effect.
Conclusions:
- Solvent polarity and coordinating ability indirectly modulate ET by affecting excited state energies and electronic coupling.
- Non-radiative decay pathways, particularly in protic solvents, are critical for EuIII emission quenching.
- The study highlights the complex interplay of factors governing luminescence in d-f heterobimetallic systems, guiding future material design.
Keywords:
Bimetallic complexesEnergy transferEuropiumIridiumJudd–Ofelt parametersPhotoluminescenceSolvent effectsMore Related Videos
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