Enhanced Performance of Dispenser Printed MA n-type Bi2Te3 Composite Thermoelectric Generators

This work presents performance advancements of dispenser printed composite thermoelectric materials and devices. Dispenser printed thick films allow for low-cost and scalable manufacturing of microscale energy harvesting devices. A maximum ZT value of 0.31 has been achieved for mechanically alloyed (MA) n-type Bi2Te3-epoxy composite films with 1 wt % Se cured at 350 degrees C. The enhancement of ZT is a result of increase in the electrical conductivity through the addition of Se, which ultimately lowers the sintering temperature (350 degrees C). A 62 single-leg thermoelectric generator (TEG) prototype with 5 mm x700 mu m x 120 mu m printed element dimensions was fabricated on a custom designed polyimide substrate with thick metal contacts. The prototype device produced a power output of 25 mu W at 0.23 mA current and 109 mV voltage for a temperature difference of 20 degrees C, which is sufficient for low power generation for autonomous microsystem applications.