A review of flexible perovskite oxide ferroelectric films and their application

Many perovskite oxide ferroelectrics (e.g. PbZr1-xTixO3, BaTiO3, LiNbO3) are born with multitudinous robust performances and have been widely used in sensors, actuators, surface acoustic wave devices, and memories et al. However, their hardness, brittleness and harsh synthesis conditions (i.e. high temperature and oxygen ambience) restrain their application into flexible electronic devices which are significant components among the three pillars of modern society development, i.e. energy, information and materials. Here we review the preparation of flexible devices based on these oxide ferroelectrics, including transferring these freestanding films to flexible substrates after separating ferroelectric oxide films from the hard substrates, such as Si and SrTiO3 crystals, and also direct fabrication methods without transferring process. Subsequently, we summarize three kinds of representative flexible devices, i.e. flexible ferroelectric memories, sensors and generators. These inorganic electronics not only show excellent electric properties competitive with those corresponding electronics on hard substrates but also exhibit good flexibility similar to many organic flexible electronics.