TY  - JOUR
A1  - Kroh, Daniel
A1  - Eller, Fabian
A1  - Schötz, Konstantin
A1  - Wedler, Stefan
A1  - Perdigón-Toro, Lorena
A1  - Freychet, Guillaume
A1  - Wei, Qingya
A1  - Dörr, Maximilian
A1  - Jones, David
A1  - Zou, Yingping
A1  - Herzig, Eva M.
A1  - Neher, Dieter
A1  - Köhler, Anna
T1  - Identifying the signatures of intermolecular interactions in blends of PM6 with Y6 and N4 using absorption spectroscopy
JF  - Advanced functional materials
N2  - In organic solar cells, the resulting device efficiency depends strongly on the local morphology and intermolecular interactions of the blend film. Optical spectroscopy was used to identify the spectral signatures of interacting chromophores in blend films of the donor polymer PM6 with two state-of-the-art nonfullerene acceptors, Y6 and N4, which differ merely in the branching point of the side chain. From temperature-dependent absorption and luminescence spectroscopy in solution, it is inferred that both acceptor materials form two types of aggregates that differ in their interaction energy. Y6 forms an aggregate with a predominant J-type character in solution, while for N4 molecules the interaction is predominantly in a H-like manner in solution and freshly spin-cast film, yet the molecules reorient with respect to each other with time or thermal annealing to adopt a more J-type interaction. The different aggregation behavior of the acceptor materials is also reflected in the blend films and accounts for the different solar cell efficiencies reported with the two blends.
KW  - charge-transfer states
KW  - Frank-Condon analysis
KW  - morphology
KW  - organic solar cells
Y1  - 2022
U6  - https://doi.org/10.1002/adfm.202205711
SN  - 1616-301X
SN  - 1616-3028
VL  - 32
IS  - 44
PB  - Wiley-VCH
CY  - Weinheim
ER  -