We review the Stille coupling synthesis
of P(DPP2OD-T) (Poly[[2,5-di(2-octyldodecyl)pyrrolo[3,4-<i>c</i>]pyrrole-1,4(2<i>H</i>,5<i>H</i>)-dione-3,6-diyl]-<i>alt</i>-[2,2′:5′,2″-terthiophene-5,5″-diyl]])
and show that high-quality, high molecular weight polymer chains are
already obtained after as little as 15 min of reaction time. The results
of UV–vis spectroscopy, grazing incidence wide-angle X-ray
scattering (GIWAXS), and atomic force microscopy show that longer
reaction times are unnecessary and do not produce any improvement
in film quality. We achieve the best charge transport properties with
polymer batches obtained from short reaction times and demonstrate
that the catalyst washing step is responsible for the introduction
of charge-trapping sites for both holes and electrons. These trap
sites decrease the charge injection efficiency, strongly reducing
the measured currents. The careful tuning of the synthesis allows
us to reduce the reaction time by more than 100 times, achieving a
more environmentally friendly, less costly process that leads to high
and balanced hole and electron transport, the latter being the best
reported for an isotropic, spin-coated DPP polymer
