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Field Effect versus Driving Force: Charge Generation in Small‐Molecule Organic Solar Cells
Author(s) -
Nikolis Vasileios C.,
Dong Yifan,
Kublitski Jonas,
Benduhn Johannes,
Zheng Xijia,
Huang Chengye,
Yüzer A. Celil,
Ince Mine,
Spoltore Donato,
Durrant James R.,
Bakulin Artem A.,
Vandewal Koen
Publication year - 2020
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202002124
Subject(s) - photocurrent , materials science , organic solar cell , acceptor , chemical physics , exciton , optoelectronics , organic semiconductor , bilayer , electron , hybrid solar cell , dissociation (chemistry) , open circuit voltage , electron acceptor , charge carrier , photochemistry , solar cell , voltage , polymer solar cell , chemistry , condensed matter physics , physics , polymer , biochemistry , quantum mechanics , membrane , composite material
Efficient charge generation in organic semiconductors usually requires an interface with an energetic gradient between an electron donor and an electron acceptor in order to dissociate the photogenerated excitons. However, single‐component organic solar cells based on chloroboron subnaphthalocyanine (SubNc) have been reported to provide considerable photocurrents despite the absence of an energy gradient at the interface with an acceptor. In this work, it is shown that this is not due to direct free carrier generation upon illumination of SubNc, but due to a field‐assisted exciton dissociation mechanism specific to the device configuration. Subsequently, the implications of this effect in bilayer organic solar cells with SubNc as the donor are demonstrated, showing that the external and internal quantum efficiencies in such cells are independent of the donor‐acceptor interface energetics. This previously unexplored mechanism results in efficient photocurrent generation even though the driving force is minimized and the open‐circuit voltage is maximized.