PORTLAND, Ore. ó The nascent field of piezoelectric energy harvesting got a boost recently when researchers reported the creation of nanogenerators on both silicon and polymer substrates.
The eventual aim is the design of energy harvesters that could power small electronic devices from environmental motions. A medical implant, for example, might be powered by the mechanical energy in flowing blood. Besides medical implants, the researchers are targeting applications of wireless sensors and portable electronic devices on "stretchable" substrates.
The researchers, led by professor Yong Shi at Stevens Institute of Technology (Hoboken, N.J.), claim their use of lead zirconate titanate (PZT) nanomaterials promises higher-output devices than competing devices using zinc oxide piezoelectrics. Thus far, their most successful energy harvesters have been able to generate 1.6 volts at 30 nanoamps, but the group plans to increase both the voltage and current output capabilities of future piezoelectric nanogenerators by adding more fibers and optimizing the architecture.
In the team's most recent device, PZT nanofibers measuring about 60 nanometers x 500 microns were aligned on a stretchable polymer substrate atop interdigitated electrodes made from fine platinum wires.
According to Stevens, the tiny nanogenerators could eventually power nanorobots that would inhabit a patient's bloodstream for extended periods, taking samples and transmitting diagnostic data to doctors for analysis.