Enhanced thermoelectric performance of hot-pressed n-type Ag2Se nanostructures by controlling the intrinsic lattice defects

Ag2Se is a promising thermoelectric (TE) material for room-temperature (RT) applications owing to its excellent TE properties. In this work, we prepared Ag-deficient Ag2Se using a hydrothermal method, and a hot-press densification process. The effect of TE properties was scientifically investigated. The calculated density of states (DOS) effective mass (m*) increased on increasing the Ag content, which must also be a reason for the enhanced maximum zT of 0.43 at 393 K for Ag1.99Se. Moreover, complex nanostructures, including grain boundaries, nanograins, and lattice distortions, were obtained in Ag2-xSe. Thus, the nanostructures strengthened the phonon scattering that leads to reduction in the total thermal conductivity (kappa) in the range of 0.9-1.1 W m(-1) K-1 in Ag2-xSe at 303 K. The aim of our work was to increase the TE performance of Ag2-xSe as a promising candidate for room temperature (RT) thermoelectric applications.

Automated summary

In this study, Ag-deficient Ag2Se was prepared using a hydrothermal method and hot-press densification process, and the effect on thermoelectric properties was investigated. The research found that increasing the Ag content led to an increase in the calculated density of states effective mass (m*), resulting in an enhanced maximum zT of 0.43 at 393 K for Ag1.99Se. Furthermore, the complex nanostructures including grain boundaries, nanograins, and lattice distortions in Ag2-xSe contributed to reduced thermal conductivity (kappa) in the range of 0.9-1.1 W m(-1) K-1 at 303 K. The aim was to improve the thermoelectric performance of Ag2-xSe for room temperature applications.