Flexible inorganic piezoelectric functional films and their applications

Piezoelectric materials play an increasingly important role in energy harvesters, sensors, and actuators. Flexible and thin piezoelectric films have been demonstrated to provide advanced functionalities and improved performances. However, the research on flexible inorganic piezoelectric thin films has rarely been systematically summarized. Here, we summarize the recent advances in the flexible inorganic piezoelectric thin films, focusing on their structural designs, fabrication techniques, and applications in various practical scenarios. Specifically, different fabrication techniques suitable for diverse inorganic piezoelectric nanostructures are reviewed, including sol–gel, hydrothermal, electrospinning, and other techniques, and the integration process with flexible substrates is further discussed. Biomedical and industrial applications of the flexible piezoelectric thin films are emphasized. Finally, some existing challenges and future perspectives are discussed.