Enhanced charge transport by incorporating additional thiophene units in the poly(fluorene-thienyl-benzothiadiazole) polymer

► Comparative study of two donor-acceptor polyfluorene copolymers: F8TTBTT and F8TBT. ► F8TTBTT contains more thiophene moieties in its monomer unit compared to F8TBT. ► Enhanced ambipolar charge transport was found in F8TTBTT. ► Correlation between transport and molecular conformation by Raman spectroscopy. ► Realization of light-emitting ambipolar transistors with deep red emission.