Flexible thermoelectric energy harvesting devices via aerosol jet printed bismuth telluride (Bi₂Te₃) nanowires and intense pulsed light sintering

Flexible thermoelectric devices offer great promise in converting waste energy into electrical energy for wearable electronics, soft robotics, and bendable sensor systems. In this work, we report the scalable fabrication of flexible thermoelectric films by aerosol jet printing of Bi₂Te₃-based nanowires onto a PLA nanofiber-based substrate, followed by optimized intense pulsed light (IPL) sintering. We optimized atomizer, ink, and sheath flows, as well as print speed, to ensure uniform and precise pattern deposition. Optical and SEM analyses revealed that the as-printed films form an intertwined, agglomerated network. This network is distinct from the aligned nanowires observed in drop-cast samples. The difference likely arises from the high shear forces and rapid solvent evaporation inherent to the aerosol jet process. Subsequent IPL sintering, performed at an optimized sintering distance and number of pulses, effectively densified the films without damaging the underlying PLA nanofiber on the substrate. These enhancements in film morphology and densification are crucial for minimizing interparticle resistance and promoting efficient carrier transport, ultimately boosting the thermoelectric performance. This study demonstrates a promising approach for the fabrication of high-resolution, flexible thermoelectric devices suitable for powering next-generation flexible Internet of things (IoT) devices by tapping on waste heat energy.