The molecular aggregation and ordering in polymer semiconductors critically influence their optoelectronic properties; yet, controlling these features in non-regiocontrolled (NR) polymers remains a challenge due to their inherent steric disorder. In this study, we demonstrate a targeted solvent-free approach to induce high-coherence J-aggregation in NR-poly(3-hexylthiophene) (NR-P3HT) thin films using the friction transfer method. While NR-P3HT typically adopts a disordered or weak H-aggregate configuration, we show that applying a mechanical shear specifically at the liquid crystalline (LC) transition temperature (∼110 °C) overcomes the kinetic barriers to ordering. By systematically optimizing the applied load and substrate temperature, we achieved thin films with unprecedented vibronic spectral signatures, where the 0–0 transition dominates (A00 A01), indicative of J-aggregate behavior and extended intrachain coherence. This structural evolution was corroborated by polarized absorption spectroscopy, Raman shifts, and x-ray diffraction, which revealed a transition from face-on to edge-on orientation, with enhanced backbone planarity. These findings establish that the synergistic coupling of thermal activation at the LC transition with a mechanical shear can unlock highly ordered, J-aggregate morphologies in low-cost, amorphous polymers, offering a sustainable route to high-performance organic electronics.
Gaurav et al. (2026) studied this question.