Flexible all-inorganic BiFeO3-based film with high piezoelectric coefficient for energy harvesting and sensing

With the development of new sensor technology, flexible piezoelectric materials possessing exceptional mechanical-to-electrical energy conversion capabilities hold great promise for application in a variety of sectors, including biomedicine, flexible robotics, and wearable electronic devices. This work reports the successful growth of an all-inorganic transparent Bi(Fe 0.95 Mn 0.05 )O 3 (BFOMn) film on the Mica substrate using a straightforward one-step sol–gel method. The prepared BFOMn thin film enables the optimum electrical properties with a saturated polarization of ~ 92 μC/cm 2 , a remanent polarization of ~ 74 μC/cm 2 , and a high piezoelectric constant d 33  of ~ 405 pm/V. Concurrently, the film exhibits exceptional adaptability without compromising its electrical performance, as evidenced by its capacity to undergo a tight curve with a radius of just 2 mm. Utilizing this BFOMn film, the fabricated flexible piezoelectric energy harvester (FPEH) has exceptional energy collecting capabilities, producing an output voltage of 15 V, a short current of 130 nA, and a notable force sensitivity of 4 V·N −1 before poling. It can also be employed to monitor human actions, such as hand hammering, hand clapping, and foot stepping. This work demonstrates the potential of the BiFeO 3 -based FPEH/sensor in the field of new intelligent electronics.