3D Conformal Printing and Photonic Sintering of High‐Performance Flexible Thermoelectric Films Using 2D Nanoplates

Flexible thermoelectric (TE) devices hold great promise for energy harvesting and cooling applications, with increasing significance to serve as perpetual power sources for flexible electronics and wearable devices. Despite unique and superior TE properties widely reported in nanocrystals, transforming these nanocrystals into flexible and functional forms remains a major challenge. Herein, demonstrated is a transformative 3D conformal aerosol jet printing and rapid photonic sintering process to print and sinter solution‐processed Bi2Te2.7Se0.3 nanoplate inks onto virtually any flexible substrates. Within seconds of photonic sintering, the electrical conductivity of the printed film is dramatically improved from nonconductive to 2.7 × 104 S m−1. The films demonstrate a room temperature power factor of 730 µW m−1 K−2, which is among the highest values reported in flexible TE films. Additionally, the film shows negligible performance changes after 500 bending cycles. The highly scalable and low‐cost fabrication process paves the way for large‐scale manufacturing of flexible devices using a variety of high‐performing nanoparticle inks. A 3D conformal aerosol jet printing and rapid photonic sintering process is developed to transform 2D Bi2Te2.7Se0.3 nanoplate inks into flexible thermoelectric films. Within seconds of photonic sintering, the printed films demonstrate orders of magnitude increases in electrical conductivity, and a room‐temperature power factor of 730 µWm−1 K−2, which is among the highest values in flexible thermoelectric films.