Small
push–pull molecules attract much attention as prospective
donor materials for organic solar cells (OSCs). By chemical engineering,
it is possible to combine a number of attractive properties such as
broad absorption, efficient charge separation, and vacuum and solution
processabilities in a single molecule. Here we report the synthesis
and early time photophysics of such a molecule, TPA-2T-DCV-Me, based
on the triphenylamine (TPA) donor core and dicyanovinyl (DCV) acceptor
end group connected by a thiophene bridge. Using time-resolved photoinduced
absorption and photoluminescence, we demonstrate that in blends with
[70]PCBM the molecule works both as an electron donor and hole acceptor,
thereby allowing for two independent channels of charge generation.
The charge-generation process is followed by the recombination of
interfacial charge transfer states that takes place on the subnanosecond
time scale as revealed by time-resolved photoluminescence and nongeminate
recombination as follows from the OSC performance. Our findings demonstrate
the potential of TPA-DCV-based molecules as donor materials for both
solution-processed and vacuum-deposited OSCs.