Assembling of Thick PZT Sheet on Silicon for Energy Harvesting Applications

Bulk PZT ceramics provide high electromechanical coupling (k) which is desirable for piezoelectric energy harvesters since the energy transformed from a mechanical agitation into an electrical output is proportional to k2 [1-2]. However, piezoelectric cantilever-based energy harvesters using bulk PZT require a bonding layer to couple the thick PZT sheet to the elastic layer substrate, typically silicon. We present the characteristics and performance of vibration energy harvesters comparing three different bonding interfaces: a UV cured glue (Delo 4552), BiSn soldering, and a dry foil laminated photoresist. The later is demonstrated to be advantageous as it can be easily patterned with photolithography, it has a well defined thickness, and it provides good adhesion to a variety of substrate materials (metal, glass, silicon, and plastic).