Field Effect versus Driving Force: Charge Generation in Small-Molecule Organic Solar Cells
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Tarih
2020
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Wiley-V C H Verlag Gmbh
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
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.
Açıklama
Anahtar Kelimeler
charge generation, driving force, field‐ dependent, organic solar cells, ultrafast spectroscopy
Kaynak
Advanced Energy Materials
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
