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Thermochemical Studies of NiII and ZnII Ternary Complexes Using Ion Mobility-Mass Spectrometry
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Near-Degenerate T2-State Assisted Thermally Activated Delayed Fluorescence in Carbene-Metal-Amide Complexes: A
Teng-Fei He1,2, Yuan-Nan Chen1,3, Xue-Li Hao4
1Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, P. R. China.
The Journal of Physical Chemistry Letters
|December 26, 2025
Summary
This study reveals a new mechanism for high efficiency in carbene-metal-amide (CMA) emitters, driven by ligand-centered charge transfer and near-degenerate states, enhancing thermally activated delayed fluorescence (TADF) performance.
Area of Science:
- Materials Science
- Quantum Chemistry
- Photophysics
Background:
- Two-coordinated carbene-metal-amide (CMA) complexes are key thermally activated delayed fluorescence (TADF) emitters.
- The precise mechanisms behind their high efficiency require further investigation.
Purpose of the Study:
- To conduct a systematic theoretical investigation of two CMA complexes (M = Cu(I), Ag(I)).
- To elucidate the underlying mechanisms of efficient TADF in these systems.
Main Methods:
- Theoretical study of CMA complexes featuring cyclic alkyl(amino)carbene (CAAC) ligands and carbazolyl amide donors.
- Analysis of electronic structure, charge transfer pathways, and excited state properties.
Main Results:
- Delayed fluorescence originates from ligand-centered intermolecular charge transfer, with minimal metal involvement.
- Efficient reverse intersystem crossing is facilitated by near-degenerate T1 and T2 states.
- A mirrored hole-electron distribution, similar to the multiple-resonance effect, enhances TADF.
Conclusions:
- A novel TADF mechanism in CMA emitters is identified.
- Design strategies for efficient metal-assisted TADF materials can be developed through electronic degeneracy and spatial overlap control.
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