The recent discovery of robst and flexible nanomaterials has changed people's perception of piezoelectric ceramics as fragile and brittle. Generators based on piezoelectric nanomaterials have the potential to harvest otherwise wasted mechanical energy and produce needed renewable electricity. The unique coupling between piezoelectric and semiconducting properties has revealed variety novel applications, such as transistors and sensors. However, limited understanding of energy conversion at the nanoscale has become a serious hurdle for practical applications with piezoelectric nanomaterials. Our group aim to overcome this hurdle by developing a 3-dimensional energy harvester and ultrasensitive sensors, which capitalizes on the significant advantages in material properties and dynamics that nanowires offer.