Preparation of Highly Orientated Diisopropylammonium Bromide Films and the Domain Evolution in Field‐Induced Phase Transition

Abstract Highly (001)‐orientated diisopropylammonium bromide (DIPAB) films were prepared by spin‐coating method. The temperature and concentration of spin‐coating solution were changed to investigate their impact on the growth of films. As the concentration increases and the temperature rises, uniform and integrated films could be obtained. The temperature‐dependent variation of dielectric constant was studied, indicating a Curie temperature of 150 °C. The in situ domain structure evolution induced by temperature confirmed that this temperature corresponds to the ferroelectric to paraelectric phase transition. Additionally, electric field‐induced domain evolution was investigated after a DC bias of 15 kV/cm was applied. Coarse domains narrowed while new fine stripe‐like domains emerged, indicating electric‐field‐driven domain reconfiguration. It revealed that the applied field reduces switching energy barriers. This drives polarization, reorientation, and elastic strain relaxation via domain wall redistribution. These findings highlight the interplay between external stimuli and domain behavior in molecular ferroelectrics, offering insights for designing tunable ferroelectric devices.