Controllable Charge-Transfer Mechanism at Push-Pull Porphyrin/Nanocarbon Interfaces
Item Type:Journal Article
Citation:Arpaçay, P., Maity, P., Meindl, A., Plunkett, S., Akca, S., Senge, M.O., Blau, W.J. & Mohammed, O.F., Controllable Charge-Transfer Mechanism at Push-Pull Porphyrin/Nanocarbon Interfaces, 2019, Journal of Physical Chemistry C, 123, 23
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Ultrafast charge transfer at the interfaces between 5,15-donor-acceptor push-pull porphyrins (Por-tBu and Por-OC8) and nanocarbon materials in the form of fullerene (C60) and graphene carboxylate (GC) are investigated using femtosecond (fs) pump-probe spectroscopy with broadband capabilities. The strong photoluminescence (PL) quenching of the porphyrin indicates electron and/or energy transfer from the photoexcited porphyrin to the nanocarbon materials. More interestingly, the Stern-Volmer plots of PL quenching shows linear and nonlinear patterns upon increasing the concentration of GC or C60 in the porphyrin solution, respectively, clearly indicating static and a combination of static and dynamic quenching at the interfaces with these nanocarbon materials. Using femtosecond transient absorption (TA) spectroscopy, ultrafast electron transfer from a singlet-excited porphyrin to the nanocarbon materials is clearly identified by the fast ground state bleach recovery and the formation of cation radical species. Furthermore, a fs-TA study revealed that both porphyrins show very long-lived ground state bleach (GSB) and excited state absorption (ESA), which can be attributed to the triplet-state formation. This work provides new physical insights into the electron transfer process and its driving force in donor-accepter systems that include nanocarbon materials.
Science Foundation Ireland
Author: Blau, Werner; Senge, Mathias; Apraçay, Pinar; Maity, Partha; Meindl, Alina; Plunkett, Shane; Akca, Sevilay; Mohammed, Omar F.
Type of material:Journal Article
Series/Report no:Journal of Physical Chemistry C;
Availability:Full text available
Keywords:Ultrafast charge transfer, Charge transfer, Absorption, Pyrroles, Chromatogrpahy quenching