Christian Kästner, Koen Vandewal, Daniel Ayuk Mbi Egbe, Harald Hoppe,
"Revelation of Interfacial Energetics in Organic Multiheterojunctions"
, in Advanced Science, Vol. 4, Nummer 4, WILEY_VCH Verlag GmbH & Co. KGaA, Weinheim, Seite(n) 1600331, 4-2017, ISSN: 2198-3844
Original Titel:
Revelation of Interfacial Energetics in Organic Multiheterojunctions
Sprache des Titels:
Englisch
Original Kurzfassung:
Efficient charge generation via exciton dissociation in organic bulk heterojunctions
necessitates donor?acceptor interfaces, e.g., between a
conjugated polymer and a fullerene derivative. Furthermore, aggregation
and corresponding structural order of polymer and fullerene domains
result in energetic relaxations of molecular energy levels toward smaller
energy gaps as compared to the situation for amorphous phases existing
in homogeneously intermixed polymer:fullerene blends. Here it is shown
that these molecular energy level shifts are reflected in interfacial charge
transfer (CT) transitions and depending on the existence of disordered or
ordered interfacial domains. It can be done so by systematically controlling
the order at the donor?acceptor interface via ternary blending of semicrystalline
and amorphous model polymers with a fullerene acceptor. These
variations in interfacial domain order are probed with luminescence spectroscopy,
yielding various transition energies due to activation of different
recombination channels at the interface. Finally, it is shown that via this
analysis the energy landscape at the organic heterojunction interface can
be obtained.
Forschungs-