Printed Se-Doped MA n-Type Bi2Te3 Thick-Film Thermoelectric Generators

In this work, we highlight new materials processing developments and fabrication techniques for dispenser-printed thick-film single-element thermoelectric generators (TEG). Printed deposition techniques allow for low-cost and scalable manufacturing of microscale energy devices. This work focuses on synthesis of unique composite thermoelectric systems optimized for low-temperature applications. We also demonstrate device fabrication techniques for high-density arrays of high-aspect-ratio planar single-element TEGs. Mechanical alloyed (MA) -type Bi2Te3 powders were prepared by taking pure elemental Bi and Te in 36:64 molar ratio and using Se as an additive. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used to characterize the as-milled powders to confirm the Bi2Te3 phase formation and particle size below 50 m. Thermoelectric properties of the composites were measured from room temperature to 100A degrees C. We achieved a dimensionless figure of merit () of 0.17 at 300 K for MA -type Bi2Te3-epoxy composites with 2 wt.% Se additive. A 20 single-leg TEG prototype with 5 mm x 400 m x 120 m printed element dimensions was fabricated on a polyimide substrate with evaporated gold contacts. The prototype device produced a power output of 1.6 W at 40 A and 40 mV voltage for a temperature difference of 20A degrees C.