Material AgInSe2 originated from strong acoustic phonon scattering

Abstract

The chalcopyrite system, which consists of ABC2 (where A can be Cu or Ag, B can be Ga or In, and C can be Se or Te), has potential uses in thermoelectric applications. However, the lack of high-performance n-type chalcopyrite thermoelectric has hindered their practical application. This study presents a new method for inhibiting cation vacancy in AgInSe2, achieved through the addition of excessive amounts of Ag and Br doping, which further increases electronic concentration. The resulting n-type material, Ag1.03InSe1.99Br0.01, exhibited superior thermoelectric performance at high temperatures, with a ZT of 1.2 at 900 K and an average ZT of 0.75 within a temperature range of 600-900 K. The remarkable thermal performance of this material is mainly due to its extremely low lattice thermal conductivity, which is attributed to the quartic anharmonicity and nondispersive phonon dispersion relation. These findings provide new insights into developing high-performance n-type chalcopyrite thermoelectric for practical use in energy conversion technologies.