Simultaneous boost in plasticity and thermoelectric performance of Ag2Te via Ag nanotwins induced by HPHT

Ag 2 Te is a promising thermoelectric material, owing to its complex crystal structure, high carrier mobility, and tunable mechanical properties. In this work, dense Ag nanotwins were in situ formed within the Ag 2 Te matrix via high-pressure and high-temperature (HPHT) sintering. These nanotwins enhanced the plasticity of the material, resulting in a fracture strain of 14.6 %, approximately 300 % higher than that of the twin-free Ag 2 Te-473 sample. The nanotwins also improved the thermoelectric performance by boosting the Seebeck coefficient and suppressing the lattice thermal conductivity. As a result, the Ag 2 Te-773 sample achieved a peak ZT of 0.78 at 570 K. These findings demonstrate that HPHT offers a viable route to co-optimize the mechanical and thermoelectric performance in brittle fast-ion semiconductors through microstructural design.