posted on 2018-12-24, 00:00authored byBo Li, Hao Yu, Elena C. Montoto, Yun Liu, Songsong Li, Kenneth Schwieter, Joaquín Rodríguez-López, Jeffrey S. Moore, Charles M. Schroeder
Donor–acceptor
(D–A) polymers are promising materials
for organic electronics because of high charge carrier mobilities
and narrow band gaps. Despite recent progress, there is incomplete
understanding of the mechanisms underlying charge transport in these
materials. In this work, we use single molecule techniques to study
intrachain charge transport in D–A oligomers containing alternating
diketopyrrolopyrrole (DPP) acceptor and bithiophene donor units. Interestingly,
at high applied bias, longer DPPTT oligomers exhibit substantially
higher conductance compared to shorter oligomers, which is interpreted
using density functional theory (DFT) simulations. Overall, this work
provides an increased understanding of intrachain charge transport
along D–A oligomers.