Reversible Room Temperature Brittle‐Plastic Transition in Ag2Te0.6S0.4 Inorganic Thermoelectric Semiconductor

Abstract Inorganic semiconductors with superior plasticity are highly desired in current flexible electronics, which however are rarely discovered owing to their intrinsic covalent and ionic bonds. The Ag 2 Te 0.6 S 0.4 semiconductor with an amorphous phase has recently been reported to exhibit plastic deformability. In this study, the reversible brittle‐plastic transition is found in this inorganic semiconductor, and the plasticity of the Ag 2 Te 0.6 S 0.4 sample is highly related to the phase structures. The Ag 2 Te 0.6 S 0.4 with a monoclinic phase exhibits a brittle behavior, while the one with cubic‐crystalline/amorphous structure shows exceptional plasticity with a compressive strain of over 80%. Significantly, the reversible plastic‐brittle transition in Ag 2 Te 0.6 S 0.4 inorganic semiconductor can be achieved by simple heat treatment. Besides the plasticity, the cubic‐crystalline/amorphous Ag 2 Te 0.6 S 0.4 composites also possess good thermoelectric performance. This study uncovers the influence of phase structure on the mechanical properties of Ag 2 Te 0.6 S 0.4 and realizes the reversible brittle‐plastic transition, facilitating its prospective application in flexible/wearable electronics.