Stoichiometric manipulation to enhance the thermoelectric and mechanical performance of Ag2Se1+x

Abstract

Thermoelectric silver selenide alloys have attracted significant attention owing to their high carrier mobility and promising thermoelectric performance. In this study, the phase diagram window is utilized to synthesize Ag2Se1+x samples within the range of −0.02 ≤ x ≤ 0.03. It is found that an excess of Se is helpful to fabricate pure-phase Ag2Se samples at room temperature. Combined with the optimized carrier concentration and reduced thermal conductivity, Ag2Se1.03 sample exhibits an average zT ∼ 0.72 in the temperature range of 310–380 K, as well as a 25 % improvement of the Vickers hardness compared to that of the stoichiometric Ag2Se sample.