Hammering Ag2Se thermoelectric materials into complex conformal shape with maintained Harman zT

Conformal shaping of thermoelectric (TE) materials is essential for integrating energy harvesting devices, thermal management, and temperature sensing onto irregular surfaces in flexible or wearable electronics. Processing and figure of merit (zT) measurement of conformal TE materials remains a challenge. We introduce a novel mechanical hammering technique to fabricate high-performance Ag₂Se TE materials into complex conformal shapes while preserving their excellent TE properties. A specialized Harman measurement system was developed to accurately characterize the zT curved geometries, overcoming limitations of conventional TE measurement approaches. We successfully produced Ag₂Se films with curvature radii of 5 mm, 10 mm, and 15 mm, as well as a sophisticated saddle-shaped structure incorporating both positive and negative curvatures. The hammering process induces strong grain boundaries, leading to enhanced charge transport properties without compromising the material's low thermal conductivity. The curved Ag₂Se samples exhibit a remarkable peak zT of ~1.0 at room temperature, matching the performance of traditional bulk forms. This work establishes a scalable mechanical processing route for creating flexible, high-efficiency TE materials in diverse conformal configurations, opening new possibilities for their integration into wearable electronics, curved-surface energy harvesters, and advanced thermal management systems.