n-Type thermoelectric metal chalcogenide (Ag,Pb,Bi)(S,Se,Te) designed by multi-site-type high-entropy alloying

Abstract

A metal chalcogenide (Ag,Pb,Bi)(S,Se,Te) with an NaCl-type structure was designed by multi-site-type high-entropy alloying (MST-HEA), and the thermoelectric properties were investigated. In this material, both cation and anion sites were alloyed and thus its total entropy of mixing ΔSmix (total) achieved 2.00R (R: gas constant). It was found that present sample is an n-type semiconductor with ultra-low lattice thermal conductivity (κL) of 0.62 Wm−1K−1 at room temperature and 0.46 Wm−1K−1 at T = 723 K. Very low κL and good power factor resulted in figure of merit of 0.54 at T = 723 K.

Keywords

• high-entropy-alloy
• material design
• new thermoelectric material
• nacl-type structure