Improvement of thermoelectric performance of copper-deficient compounds Cu_2.5+δ In_4.5Te₈ (δ = 0-0.15) due to a degenerate impurity band and ultralow lattice thermal conductivity.

ABSTRACT: Cu-In-Te ternary chalcogenides have unique crystal and band structures; hence they have received much attention in thermoelectrics. In this work we have observed an enhancement in Hall carrier concentration (n _H) and ultralow lattice thermal conductivity (κ _L) when Cu was added to ternary Cu_2.5+δ In_4.5Te₈ (δ = 0-0.15) compounds. The enhancement in n _H is attributed to a degenerate impurity band at the G point in the valence band maximum (VBM), while the extremely low κ _L results from the increased lattice disorder. We thus obtained the minimum κ _L value of only 0.23 W K^-1 m^-1 in the sample at δ = 0.1 and 820 K, which is in goo

SUBMITTER: Ren T 

PROVIDER: S-EPMC9083297 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature