Homo-composition and hetero-structure nanocomposite Pnma Bi2SeS2 - Pnnm Bi2SeS2 with high thermoelectric performance

This is the authors' abstract. We don't add key points for this paper.

Nanocomposite engineering decouples the transport of phonons and electrons. This usually involves the in-situ formation or ex-situ addition of nanoparticles to a material matrix with hetero-composition and hetero-structure ( he C- he S) interfaces or hetero-composition and homo-structure ( he C- ho S) interfaces. Herein, a quasi homo-composition and hetero-structure ( ho C- he S) nanocomposite consisting of Pnma Bi 2 SeS 2 - Pnnm Bi 2 SeS 2 is obtained through a Br dopant-induced phase transition, providing a coherent interface between the Pnma matrix and Pnnm second phase due to the slight structural difference between the two phases. This ho C- he S nanocomposite demonstrates a significant reduction in lattice thermal conductivity (~0.40 W m −1 K −1 ) and an enhanced power factor (7.39 μW cm −1 K −2 ). Consequently, a record high figure-of-merit ZT max = 1.12 (at 773 K) and a high average figure-of-merit ZT ave = 0.72 (in the range of 323–773 K) are achieved. This work provides a general strategy for synergistically tuning electrical and thermal transport properties by designing ho C- he S nanocomposites through a dopant-induced phase transition.