Unfolding the cocrystallization-charge transport correlation in all-conjugated triblock copolymers via meticulous molecular engineering for organic field-effect transistors

The ability to render the cocrystallization over microphase separation in all-conjugated block copolymers represents an important endeavor towards achieving enhanced charge transport. This, however, remains a grand challenge, particularly in all-conjugated triblock copolymers. Herein, we report the unravelling of the dependence of cocrystallization in all-conjugated triblock copolymers on a set of internal structural parameters, and more importantly, the scrutiny of the correlation of their unique cocrystalline structures to charge transport properties for organic field-effect transistors (OFETs). Specifically, a series of poly(3-butylthiophene)-block-poly (3-alkylthiophene)-block-poly(3-hexylselenophene) triblock copolymers (denoted P3BT-b-P3AT-b-P3HS) are meticulously designed and synthesized. Intriguingly, a shorter alkyl side chain length and a shorter main chain length of the central P3AT, as well as a stronger cocrystallization ability of the two outer blocks (P3BT and P3HS), are found to favor the cocrystallization of the three dissimilar blocks in P3BT-b-P3AT-b-P3HS. Notably, the charge transport properties of P3BT-b-P3AT-b-P3HS correlate strongly to their various crystalline structures, thereby imparting their utility for high-performance OFETs. This study highlights the robustness of meticulous molecular engineering of all-conjugated multiblock copolymers in tailoring their cocrystallization behavior and in turn charge transport characteristics that underpins their advances in optoelectronic materials and devices.

Automated summary

The ability to control cocrystallization behavior through meticulous design and synthesis of multiblock copolymers can enhance charge transport properties, providing important guidance for the development of high-performance organic field-effect transistors (OFETs).