Record High Hole Mobility in Polymer Semiconductors via Side-Chain Engineering

TLDR

Charge carrier mobility remains the key challenge for practical organic electronics. The study demonstrates that smart side‑chain engineering can enhance intermolecular electronic communication in polymer semiconductors. By shifting the side‑chain branching position away from the backbone, the polymers exhibit stronger intermolecular interactions and shorter π–π stacking distances while retaining solubility. The resulting polymers P‑29‑DPPDBTE and P‑29‑DPPDTSE achieve record hole mobilities of 12 cm² V⁻¹ s⁻¹, even in room‑temperature devices.

Abstract

Charge carrier mobility is still the most challenging issue that should be overcome to realize everyday organic electronics in the near future. In this Communication, we show that introducing smart side-chain engineering to polymer semiconductors can facilitate intermolecular electronic communication. Two new polymers, P-29-DPPDBTE and P-29-DPPDTSE, which consist of a highly conductive diketopyrrolopyrrole backbone and an extended branching-position-adjusted side chain, showed unprecedented record high hole mobility of 12 cm2/(V·s). From photophysical and structural studies, we found that moving the branching position of the side chain away from the backbone of these polymers resulted in increased intermolecular interactions with extremely short π–π stacking distances, without compromising solubility of the polymers. As a result, high hole mobility could be achieved even in devices fabricated using the polymers at room temperature.