Reduced coercive field and promoted ferroelectric polarization of BiFeO3/P(VDF-TrFE) gradient structure composite films

We designed novel BiFeO 3 /P(VDF-TrFE) gradient structures and spun coating composite films on a fluorine-doped tin oxide (FTO) conductive glass substrate. A large remnant ferroelectric polarization of 29.5 μC/cm 2 , a 210 % improvement over the pure P(VDF-TrFE) film, is achieved by BiFeO 3 nanoparticles embedment, with the coercive electric field E c effectively restrained by 12 %. The structure analysis showed increased polar phase, reduced crystal size, and established long chains after BiFeO 3 gradient incorporation, which are essential to the ferroelectric performances. The finite element simulation by COMSOL software illustrated an apparent potential redistribution up to 342 MV/m at an external electric field of 160 MV/m and large leakage currents around BiFeO 3 , which reflect the heterogeneous regions formed at the interfaces and they are contributive to the micromorphology. These gradient composite films have potential in the low electric field driving flexible electronic devices.