Piezoelectricity—An important property for ferroelectrics during last 100 years

As an important member of the dielectric family, ferroelectric materials are known for their various physical properties and have been attracted considerable attention from both scientific respect and technology respect. Piezoelectricity is one of the most important properties of ferroelectrics, which has been widely used in many devices for the conversion between electric energy and mechanical energy. For example, the main piezoelectric elements of underwater acoustic transducers, medical imaging systems, piezoelectric actuators, etc., are all ferroelectrics. In this paper, the history of the piezoelectric effect in lead-based perovskite ferroelectrics is introduced, and the relationship among the microstructure, the state of polarization and the piezoelectricity is discussed. In addition, we introduce some important factors for optimizing the piezoelectricity of ferroelectrics, such as morphotropic phase boundary, soft doping, polarization rotation, local structural heterogeneity, etc. It is expected that this paper could shed light on the future design of ferroelectric materials with various functionalities.