Homo- or Hetero- Triplet-Triplet Annihilation? A Case Study with Perylene-Bodipy Dyads/Triads
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AbstractThe photophysical processes of intramolecular ‘ping-pong’ energy transfers in the iodinated reference dyad BDP-I2-Py, as well as the uniodinated dyad BDP-Py and triad BDP-2Py, were studied. For BDP-I2-Py, a forward Förster resonance energy transfer (FRET) from the perylene (Py) unit to the diiodoBDP unit (7 ps) and a backward triplet energy transfer (TTET, 3 ns) from the diiodoBDP unit to the Py unit were observed. For the BDP-Py and BDP-2Py systems, a FRET (5 ~ 8 ps) and a photo-induced electron transfer (PET) (1-1.5 ns) were observed in acetonitrile. The uniodinated dyad and triad were used as the triplet energy acceptor and emitter for a TTA upconversion with palladium tetraphenyltetrabenzoporphyrin as the triplet photosensitizer. A maximum upconversion quantum yield of 12.6 % was measured. Given that the dyad (BDP-Py) contains one BDP unit and one Py unit, while the triad (BDP-2Py) contains two Py units and one BDP unit, and based on the results from steady-state femtosecond and nanosecond transient optical spectroscopies, it is concluded that neither intramolecular homo- triplet-triplet annihilation (TTA) nor intramolecular hetero-TTA is possible during a TTA upconversion for those upconversion systems.
CitationCui X, El-Zohry AM, Wang Z, Zhao J, Mohammed OF (2017) Homo- or Hetero- Triplet-Triplet Annihilation? A Case Study with Perylene-Bodipy Dyads/Triads. The Journal of Physical Chemistry C. Available: http://dx.doi.org/10.1021/acs.jpcc.7b05620.
SponsorsWe thank the NSFC (21473020, 21673031, 21273028, 21421005 and 21603021), Program for Changjiang Scholars and Innovative Research Team in University [IRT_13R06], the Fundamental Research Funds for the Central Universities (DUT16TD25, DUT15ZD224, DUT2016TB12) for financial support. We would like to thank Dr. Manas Parida for his useful contribution to this project and King Abdullah University of Science and Technology (KAUST) for the financial support.
PublisherAmerican Chemical Society (ACS)