Prolonged Charge Separated States in Twisted Stacks of All-Carbon Donor and Acceptor Chromophores

• Published in: The journal of physical chemistry letters Vol. 7; no. 22; pp. 4751 - 4756
• Main Authors: Philip, Abbey M, Mallia, Ajith R, Hariharan, Mahesh
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 17.11.2016
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.6b02310

Twisted donor-on-donor and acceptor-on-acceptor bicontinuous assembly in all-carbon pyren-1-ylaceanthrylene (PA) dyad extends the survival time of the photoinduced radical ion-pair intermediates. Aceanthrylene, a functional analog of C70, acts as a versatile electron acceptor owing to its high electron affinity and visible light absorption. Antithetical trajectories of the excitons in the nonparallel π-ways led to persistent radical ion-pair intermediates in aggregated (τcr A ∼ 1.28 ns) vs monomeric (τcr M ≤ 110 fs) PA dyad as observed using femtosecond transient absorption spectroscopy. Marcus theory of charge transfer rates predicts an ambipolar transport characteristic in crystalline PA, thereby endorsing PA as an all-carbon DA hybrid for nonfullerene photovoltaic applications.