| Vibration-based mechanical energy is the most ubiquitous and accessible energy source in the environment. Examples include random vibrations, acoustic waves, air flows, and so forth. Harvesting this type of energy offers great potential for remote/wireless sensing, battery charging, and powering electronic devices. Compared to conventional film-based piezoelectric cantilever transducers, using piezoelectric nanowires (NWs) for mechanical energy harvesting offers three unique advantages:
Enhanced piezoelectric effect - Theory has predicted l arge enhancement of the piezoelectric effect due to the flexoelectric effect, i.e. when a strain gradient is experienced by a ferroelectric NW with a thickness of a few tens of nanometers..
Superior mechanical properties - The perfection of NWs' atomic lattice enables much larger critical strain, greater flexibility, and longer operational lifetime.
High sensitivity to small forces - High aspect ratio and small thickness allow NWs to undergo significant strain under a force at the nano Newton or even pico Newton level.
We are working to develop uniform ferroelectric nanowire arrays to understand electromechanical coupling properties at the nanometer scale, and to develop micro-/ nano-scale piezoelectric devices (nanogenerators) for harvesting mechanical energy from low-level vibrations, low-speed wind, and body movement.