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

• DOI: 10.1038/s41467-021-27564-2
• Publication Date: 2021-12-10T11:04:11Z
• Authors: Bushra Jabar; Fu Li; Zhuanghao Zheng; Adil Mansoor; Yongbin Zhu; Chongbin Liang; Dongwei Ao; Yuexing Chen; Guangxing Liang; Ping Fan; Weishu Liu
• Keywords: Science; Q; 02 engineering and technology; 0210 nano-technology; Article

AbstractNanocomposite 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 (heC-heS) interfaces or hetero-composition and homo-structure (heC-hoS) interfaces. Herein, a quasi homo-composition and hetero-structure (hoC-heS) nanocomposite consisting of Pnma Bi2SeS2 - Pnnm Bi2SeS2 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 hoC-heS 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 ZTmax = 1.12 (at 773 K) and a high average figure-of-merit ZTave = 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 hoC-heS nanocomposites through a dopant-induced phase transition.