Piezoelectric Nanofibers and Their Applications in Energy Harvesting

One dimensional nano structures such as nano-tubes, nano-wires and nano-fibers have great potential as either building blocks for micro/nano devices or as functional materials for micro-scale sensing and actuation applications. They provide more design flexibility and better performance which may not be achievable before. Piezoelectric materials such as PZT is a very good example which was commonly used in bulk or thin film forms. In this talk, the fabrication and characterization of piezoelectric (PZT) nanofibers will be discussed. We demonstrated the piezoelectric properties of polycrystalline PZT nanofibers through electro-mechanical coupling tests such as dynamic loading, mechanical vibration and electric field application using AFM. PZT nanofibers were fabricated by electrospinning process. Diameters of PZT nanofibers could be tuned from about 40 nm up to 200 nm. Titanium substrate with ZrO2 as diffusion barrier was used to collect the PZT nanofibers for the tests. The largest output voltage from the dynamic test is 170mV under 0.5% strain, which suggest that PZT nanofibers have great potentials for energy harvesting from environments. A potable piezoelectric nanogenerator based on PZT nanofiber will be discussed. It consists of PZT nanofibers aligned on interdigitated electrodes and packaged using a soft polymer on a silicon substrate. The measured output voltage under periodic stress application to the soft polymer was 1.63