Ultrathin Epidermal P(VDF-TrFE) Piezoelectric Film for Wearable Electronics

Ultrathin epidermal piezoelectric sensors are essential in the next generation of wearable flexible electronics due to their conformal contact with the skin. However, the fabrication and peeling of ultrathin film still face great challenges, and there is an urgent need to develop a facile and effective process. Here, we propose a method of combing spin-coating and aqueous phase exfoliating to prepare the ultrathin poly(vinylidene fluoride-ran-trifluoroethylene) (P(VDF-TrFE)) piezoelectric film with a thickness of about 3 μm. And the thermal treatment is employed to improve its crystallinity and piezoelectricity, resulting in the piezoelectric coefficient of 11.67 pC N–1 and fine sensitivity of 4.56 mV kPa–1. The ultrathin device is successfully applied to monitor the signals of arterial pulse and interactive force, which is expected to provide references for medical diagnosis and robot design. Notably, this work might motivate design principles and methods of ultrathin epidermal devices and promote its applications in wearable flexible electronics.