The present disclosure demonstrates that the introduction of electron deficient fullerene acceptors into thin films comprised of the high-mobility semiconducting polymers suppresses an undesirable “double-slope” in the current-voltage characteristics, improves operational stability, and changes ambipolar transport to unipolar transport. Examination of a variety of high μ polymers shows general applicability. The present disclosure also shows that instability is further reduced by tuning the relative electron affinity of the polymer and fullerene by creating blends containing different fullerene derivatives and semiconductor polymers. One can obtain hole μ values up to 5.6 cm2 V−1 s−1 that are remarkably stable over multiple bias-sweeping cycles. The results provide a simple, solution-processable route to dictate transport properties and improve semiconductor performance in systems that display similar non-idealities.