Dispenser Printed Microscale Thermoelectric Generators for Powering Wireless Sensor Networks

Wireless sensor networks (WSN) are a promising technology for ubiquitous, active monitoring in residential, industrial and medical applications. These nodes combine a radio transceiver, microcontroller and sensors into a low power package. A current bottleneck for widespread adoption of WSN’s is the power supplies. While the power demands can be somewhat alleviated through novel electronics, any primary battery will have a finite lifetime. Energy harvesting, from ambient vibration, light, and heat sources, offers an opportunity to significantly extend the lifetime of the nodes and possibly provide perpetual power. Thermal energy is an ideal source for WSNs due to the availability of low-grade ambient waste heat sources. Thermoelectric devices convert temperature gradients into DC electric power in compact form factors. Efficient device designs require hundreds of high-aspect ratio semi-conductor microelements fabricated electrically in series and thermally in parallel. This design requirement presents problems for standard microfabrication techniques due to thickness limitations of standard semiconductor processes. We present a new method of contact dispenser printing, specifically developed to additively create microscale generators. Initial materials performance results show promising results and are further detailed in this work.