Assembly of Close‐Packed Ferroelectric Polymer Nanowires via Interface‐Epitaxy with ReS₂

Abstract The flexible, transparent, and low‐weight nature of ferroelectric polymers makes them promising for wearable electronic and optical applications. To reach the full potential of the polarization‐enabled device functionalities, large‐scale fabrication of polymer thin films with well‐controlled polar directions is called for, which remains a central challenge. The widely exploited Langmuir–Blodgett, spin‐coating, and electrospinning methods only yield polymorphous or polycrystalline films, where the net polarization is compromised. Here, an easily scalable approach is reported to achieve poly(vinylidene fluoride‐trifluoroethylene) P(VDF‐TrFE) thin films composed of close‐packed crystalline nanowires via interface‐epitaxy with 1T′‐ReS₂. Upon controlled thermal treatment, uniform P(VDF‐TrFE) films restructure into about 10 and 35 nm‐wide (010)‐oriented nanowires that are crystallographically aligned with the underlying ReS₂, as revealed by high‐resolution transmission electron microscopy. Piezoresponse force microscopy studies confirm the out‐of‐plane polar axis of the nanowire films and reveal coercive voltages as low as 0.1 V. Reversing the polarization can induce a conductance switching ratio of >10⁸ in bilayer ReS₂, over six orders of magnitude higher than that achieved by an untreated polymer gate. This study points to a cost‐effective route to large‐scale processing of high‐performance ferroelectric polymer thin films for flexible energy‐efficient nanoelectronics.