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Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera
Published on: December 27, 2018
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Gold(i)-containing light-emitting molecules with an inverted singlet-triplet gap
Daniel Blasco1,2, Rinat T Nasibullin3, Rashid R Valiev1
1Department of Chemistry, Faculty of Science, University of Helsinki P.O. Box 55, (A.I. Virtasen Aukio 1) FIN-00014 Finland dage.sundholm@helsinki.fi.
Chemical Science
|April 10, 2023
Summary
This study computationally explores gold(I) coordination with heptazine derivatives, revealing potential for new organometallic delayed fluorescence from inverted singlet-triplet gap emitters.
Area of Science:
- Materials Science
- Computational Chemistry
- Photophysics
Background:
- Delayed fluorescence from molecules with an inverted singlet-triplet gap (DFIST) arises from an unusual S1/T1 state ordering in TADF emitters.
- Heptazine derivatives exhibit an inverted singlet-triplet gap due to multiple resonance effects and significant double excitation character.
Purpose of the Study:
- To computationally investigate the impact of gold(I) metalation and coordination on the optical properties of heptazine and its phosphine-functionalized derivatives.
- To explore the potential of these novel complexes as organometallic DFIST emitters.
Main Methods:
- *Ab initio* calculations using coupled cluster approximate second-order (CC2) and extended multiconfigurational quasi-degenerate perturbation theory (XMC-QDPT2) levels.
- Analysis of electronic structure, exciton localization, and spin-orbit coupling matrix elements.
Main Results:
- Heptazine derivatives (molecules 1-4) exhibit an inverted singlet-triplet gap due to alternating electron-hole localization within the heptazine core.
- A non-vanishing spin-orbit coupling and a fast intersystem crossing rate were calculated for molecule 4.
- These findings suggest potential for DFIST emission in these organometallic complexes.
Conclusions:
- Gold(I) coordination can tune the photophysical properties of heptazine derivatives.
- The studied heptazine complexes show promise as the first class of organometallic DFIST emitters.
- Further experimental validation is warranted to confirm their potential in optoelectronic applications.
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