Donor, Acceptor, and Molecular Charge Transfer Emission All in One Molecule

Franca, Larissa G.; Danos, Andrew; Monkman, Andrew

Abstract

The molecular photophysics in the thermally activated delayed fluorescence (TADF) spiro-acridine–anthracenone compound, ACRSA, is dominated by the rigid orthogonal spirocarbon bridging bond between the donor and acceptor. This critically decouples the donor and acceptor units, yielding photophysics, which includes (dual) phosphorescence and the molecular charge transfer (CT) states giving rise to TADF, that are dependent upon the excitation wavelength. The molecular singlet CT state can be directly excited, and we propose that supposed “spiro-conjugation” between acridine and anthracenone is more accurately an example of intramolecular through-space charge transfer. In addition, we show that the lowest local and CT triplet states are highly dependent upon spontaneous polarization of the environment, leading to energy reorganization of the triplet states, with the CT triplet becoming lowest in energy, profoundly affecting phosphorescence and TADF, as evident by a (thermally controlled) competition between reverse intersystem crossing and reverse internal conversion, i.e., dual delayed fluorescence (DF) mechanisms.

Citation

Franca, L. G., Danos, A., & Monkman, A. (2023). Donor, Acceptor, and Molecular Charge Transfer Emission All in One Molecule. Journal of Physical Chemistry Letters, 14(11), 2764-2771. https://doi.org/10.1021/acs.jpclett.2c03925

• Journal Article Type: Article
• Acceptance Date: Mar 3, 2023
• Online Publication Date: Mar 10, 2023
• Publication Date: Mar 23, 2023
• Deposit Date: Apr 27, 2023
• Publicly Available Date: Apr 27, 2023
• Journal: The Journal of Physical Chemistry Letters
• Electronic ISSN: 1948-7185
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 14
• Issue: 11
• Pages: 2764-2771
• DOI: https://doi.org/10.1021/acs.jpclett.2c03925
• Public URL: https://durham-repository.worktribe.com/output/1173900