Perovskite lead-free piezoelectric ceramics
The ability of piezoelectric devices to convert mechanical energy to electrical energy and vice versa has inspired remarkable growth in research on piezoelectric materials. However, based on the Restriction of Hazardous Substances legislation, it is necessary to eliminate the lead from currently used piezoelectric ceramics. Together with the increasing market share and improved performance of lead-free piezoelectrics, this growing recognition that the use of lead should be limited in piezoelectric materials has promoted the development of lead-free piezoelectric ceramics. Some devices with excellent performance based on lead-free piezoelectric ceramics have been reported, and their applications are expected to increase in the near future. This perspective provides an overview of key advances related to the structures and properties of lead-free piezoelectrics, including (K,Na)NbO3, BaTiO3, Bi0.5Na0.5TiO3, and BiFeO3. Future prospects are also discussed based on the performances of lead-free piezoelectric materials investigated to date.