Wafer-Scale Diisopropylammonium Bromide Films for Low-Power Lateral Organic Ferroelectric Capacitors

Organic ferroelectrics, particularly the polymer polyvinylidene fluoride and its copolymer polyvinylidene fluoride-trifluoroethylene, have received much attention owing to their low cost, flexibility, and convenient thin film fabrication. However, development of this outstanding material for electronic applications is significantly impeded by its attributes of large coercive electric fields and poor spontaneous polarization. While the recent breakthroughs reveal that several kinds of molecular ferroelectrics (e.g., diisopropylammonium bromide (DIPAB)) can exhibit excellent properties comparable to inorganic ferroelectrics, it is still difficult to obtain high-quality continuous thin films for ferroelectric devices with high performance. In this work, a simple solution strategy is used for the preparation of large-area high crystallinity or even single-crystal DIPAB films. Subsequently, planar ferroelectric capacitors are developed with large in-plane ferroelectric polarization. These capacitors possess excellent memory function with small operating voltages (1–3 V), and a record remnant polarization of 13 µC cm⁻² for organic ferroelectric devices. The findings have the potential to pave the way for the substitution of conventional ferroelectric polymers with DIPAB films for future organic ferroelectric devices.