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Conjugated Block Copolymers as Model Systems to Examine Mechanisms of Charge Generation in Donor–Acceptor Materials
Author(s) -
Aplan Melissa P.,
Grieco Christopher,
Lee Youngmin,
Munro Jason M.,
Lee Wonho,
Gray Jennifer L.,
Seibers Zach D.,
Kuei Brooke,
Litofsky Joshua H.,
Kilbey S. Michael,
Wang Qing,
Dabo Ismaila,
Asbury John B.,
Gomez Enrique D.
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201804858
Subject(s) - materials science , copolymer , chemical physics , acceptor , organic solar cell , conjugated system , electron acceptor , polaron , photoluminescence , photocurrent , quenching (fluorescence) , nanoparticle , exciton , intermolecular force , polymer , photochemistry , nanotechnology , electron , optoelectronics , molecule , organic chemistry , chemistry , fluorescence , condensed matter physics , physics , quantum mechanics , composite material
Fully conjugated donor–acceptor block copolymers are established as model systems to elucidate fundamental mechanisms of photocurrent generation in organic photovoltaics. Using analysis of steady‐state photoluminescence quenching, exciton dissociation to a charge transfer state within individual block copolymer chains is quantified. By making a small adjustment to the conjugated backbone, the electronic properties are altered enough to disrupt charge transfer almost entirely. Strong intermolecular coupling of the electron donor is introduced by synthesizing block copolymer nanoparticles. Transient absorption spectroscopy is used to monitor charge generation in block copolymer isolated chains and nanoparticles. While efficient charge transfer is observed in isolated chains, there is no indication of complete charge separation. In the nanoparticles, long‐lived polarons are observed as early as ≈15 ns. Thus, aggregation of electron donors can facilitate efficient charge generation.