1 research outputs found
Manipulation of Chain Conformation for Optimum Charge-Transport Pathways in Conjugated Polymers
A pair
of different diketopyrrolopyrrole-based conjugated polymers (CPs)
were designed and synthesized to investigate the effect of chain conformation
on their molecular assembly. Conformation management was achieved
by the incorporation of different linkers during polymerization. Through
the use of computational calculations and UV–vis absorption
measurements, the resulting CPs (PDPP-T and PDPP-BT) were found to
exhibit partly modulated chain geometry. Grazing incident X-ray diffraction
experiments with a two-dimensional detector revealed that PDPP-T having
a planar chain conformation exhibited an edge-on type molecular arrangement,
which evolved to a face-on type chain assembly when the planar geometry
was altered to a slightly twisted one as in PDPP-BT. In addition, it was verified that the directional electric carrier
mobility of CPs was critically distinguished by the distinctive chain
arrangement in spite of their similar chemical structure. Concentration-dependent
absorption measurements could provide an improved understanding of
the assembly mechanism of CP chains: the planar conformation of PDPP-T
facilitates the formation of preassembled chains in a concentrated
solution and further directs the edge-on stacking, while the twisted
dihedral angle along the benzothiophene in PDPP-BT prevents chain
assembly, resulting in the face-on stacking. Because CP chain conformation
is inevitably connected with the generation of preassembled chains,
manipulating CP geometry could be an efficient tool for extracting
an optimum chain assembly that is connected with the principal charge-transport
pathway in CPs