Monoisomeric Phthalocyanines and Phthalocyanine–Fullerene Dyads with Polar Side Chains: Synthesis, Modeling, and Photovoltage

Synthesis, characterization, molecular
modeling, and photovoltage
responses of four phthalocyanine–fullerene (Pc-C60) dyads with two polar (−OH) side chains are described. The
synthesized dyads have polar tails either on the Pc (electron donor
D) side or on the fullerene (electron acceptor A) side of the dyad,
providing a possibility to produce oriented donor–acceptor
(D–A) monolayers with revised electron transfer direction when
deposited on an aqueous subphase or on a solid surface. In the dyads,
phthalocyanine and fullerene have different mutual orientations: in
the trans-dyads they have face-to-face orientation, while in the cis-dyads
the orientation is face-to-edge. Molecular modeling was used to examine
and confirm the spatial arrangements of the synthesized dyads. The
Pc-C60 dyads were deposited successfully onto solid substrates
as highly oriented monolayers using the Langmuir–Schäfer
method. Formation of a vertically oriented monolayer and the following
electron transfer from the photoexcited phthalocyanine to fullerene
was demonstrated for all dyad monolayers by the time-resolved Maxwell
displacement charge method. The electron transfer direction was reversed
for the dyads with reversed polarity, demonstrating the ability to
control charge transfer direction in the film.