Low Sound Velocity Contributing to the High Thermoelectric Performance of Ag₈SnSe₆.

ABSTRACT: Conventional strategies for advancing thermoelectrics by minimizing the lattice thermal conductivity focus on phonon scattering for a short mean free path. Here, a design of slow phonon propagation as an effective approach for high-performance thermoelectrics is shown. Taking Ag₈SnSe₆ as an example, which shows one of the lowest sound velocities among known thermoelectric semiconductors, the lattice thermal conductivity is found to be as low as 0.2 W m^-1 K^-1 in the entire temperature range. As a result, a peak thermoelectric figure of merit zT > 1.2 and an average zT as high as ≈0.8 are achieved in Nb-doped materials, without relying on a high thermoelectric power factor. This work demonstrates not only a guiding principle of low so

SUBMITTER: Li W 

PROVIDER: S-EPMC5102661 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature