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) n-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 100°C. We achieved a dimensionless figure of merit (ZT) of 0.17 at 300?K for MA n-type Bi₂Te₃?Cepoxy composites with 2?wt.% Se additive. A 20 single-leg TEG prototype with 5?mm?×?400???m?×?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 20°C.