High-Performance Dispenser Printed MA p-Type Bi0.5Sb1.5Te3 Flexible Thermoelectric Generators for Powering Wireless Sensor Networks

This work presents a novel method to synthesize p-type composite thermoelectric materials to print scalable thermoelectric generator (TEG) devices in a cost-effective way. A maximum ZT of 0.2 was achieved for mechanically alloyed (MA) p-type Bi0.5Sb1.5Te3 (8 wt % extra Te additive)-epoxy composite films cured at 250 degrees C. A 50% increase in Seebeck coefficient as a result of adding 8 wt % extra Te in stoichiometric Bi0.5Sb1.5Te3 contributed to the increase in ZT. To demonstrate cost-effective and scalable manufacturing, we fabricated a sixty element thermoelectric generator prototype with 5.0 mm X 600 mu m X 120 mu m printed dimensions on a custom designed polyimide substrate with thick metal contacts. The prototype TEG device produced a power output of 20.5 mu W at 0.15 mA and 130 mV for a temperature difference of 20 K resulting in a device areal power density of 152 mu W/cm(2). This power is sufficient for low power applications such as wireless sensor network (WSN) devices.