LAUSR

Recent discovery of piezoelectricity existed in two-dimensional (2D) layered materials represents a key milestone for flexible electronics, miniaturized and wearable devices. However, the so far reported piezoe-lectricity in these 2D layered materials is too weak to be used for any practical applications. In this work, we discovered that grain boundaries (GBs) in monolayer MoS2 can significantly enhance its piezoelectric proper-ty. The output power of piezoelectric devices made of the butterfly-shaped monolayer MoS2 was improved about 50% by the GB induced piezoelectric effect. The enhanced piezoelectricity is attributed to the additional piezoelectric effect induced by the existence of deform-able GBs which can promote polarization and generates spontaneous polarization with different piezoelectric coefficients along with various directions. We further made a flexible piezoelectric device based on the 2D MoS2 with the GBs and demonstrated its potential ap-plication in self-powered precision sensors for in-situ detecting pressure changes in human blood for the health monitoring.