Multi-deformable piezoelectric energy nano-generator with high conversion efficiency for subtle body movements

Wearable devices for remote medical systems require a reliable power supply to enable full operation during long-term processes. Piezoelectric generators are promising energy sources that use human body movements to generate energy. The wearable device should be able to easily deform with tiny skin deformations to achieve continual energy generation from standard body movements. However, conventional piezoelectric devices cannot deform sufficiently in response to small movements, resulting in an extremely low energy-conversion efficiency when mounted on the human skin. In this study, we report on an ultrathin piezoelectric energy nano-generator (U-PENG) based on poly(vinylidene fluoride-trifluoroethylene). Owing to their thin structure (4 µm), the proposed U-PENGs conformally adhere to soft human skin and generate energy from subtle movements, such as eye blinking and breathing. These novel devices provide energy conversion efficiency of ~18.85%, which is ~971% higher than thicker samples with identical structures. Owing to their ultrathin structure, high efficiency, and excellent skin attachability, U-PENGs can be integrated with biodevices for use as power sources.