1 research outputs found
Intrachain Aggregation of Charge-Transfer Complexes in Conjugated Polymer:Acceptor Blends from Photoluminescence Quenching
Recent
studies of conjugated polymer donor–acceptor blends
show that the donor and acceptor can form a weak charge-transfer complex
(CTC) in the electronic ground state, and these CTCs can significantly
change the photophysics in the blend. In this work, we study photoluminescence
quenching in model polymer acceptor blends of polyÂ(methoxy,5-(2′-ethyl-hexyloxy-1,4-phenylene-vinylene))
(MEH-PPV) with TNF (2,4,7-trinitrofluorenone) in solution. Our experimental
data show that the observed strong increase in the CTC concentration
with acceptor content results only in a moderate quenching enhancement.
We propose an extended Stern–Volmer relation to model photoluminescence
quenching in conjugated polymers with statistically homogeneous distribution
of CTCs over polymer chains. We compare the experimental data with
the model and conclude that the CTCs are not randomly distributed
within a chain but form intrachain CTC clusters. These findings imply
that the CTCs can influence the morphology of donor–acceptor
blends, which is of paramount importance for the performance of organic
solar cells