Deformation mechanism and high thermoelectric performance of sodium doped Ag2S1/3Se1/3Te1/3 plastic semiconductors

Abstract

Inorganic plastic thermoelectric materials have attracted much attention for breaking the brittle bottleneck of traditional inorganic thermoelectric materials. The Ag₂(S, Se, Te) system is one of the most novel and promising thermoelectric semiconductors. To enhance its thermoelectric performance, substitution of Na for Ag is adopted to modulate the electrical and thermal transport properties of Ag₂S_1/3Se_1/3Te_1/3, through enhancing phonon scattering and effective mass. It enables us to achieve a record high average power factor (PF) of 7.4 μW cm⁻¹ K⁻² in the temperature interval of 300–500 K and a room-temperature thermoelectric figure of merit (ZT) of 0.50 and a peak ZT of 0.84 at 500 K in Ag₂(S, Se, Te), respectively. In addition, the slip mode of Ag₂S_1/3Se_1/3Te_1/3 plastic deformation is also revealed for the first time, in which the crystal slip behavior is dominated by the {112}〈111〉 slip regime, instead of the conventional {110}〈111〉 view. The obtained high thermoelectric performance, as well as the maintained plastic performance, shows broad application prospects in waste heat recovery and wearable devices.