Flexible layer-structured Bi2Te3 thermoelectric on a carbon nanotube scaffold

• Published in: Nature materials Vol. 18; no. 1; pp. 62 - 68
• Main Authors: Jin, Qun, Jiang, Song, Zhao, Yang, Wang, Dong, Qiu, Jianhang, Tang, Dai-Ming, Tan, Jun, Sun, Dong-Ming, Hou, Peng-Xiang, Chen, Xing-Qiu, Tai, Kaiping, Gao, Ning, Liu, Chang, Cheng, Hui-Ming, Jiang, Xin
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2019; Nature Publishing Group
• Subjects: 639/301; 639/301/1005; 639/301/299; 639/301/357; 639/301/357/73; Biomaterials; Bismuth tellurides; Carbon; Chemistry and Materials Science; Condensed Matter Physics; Crystal structure; Crystallography; Fabrication; Figure of merit; Flexibility; Heat conductivity; Laboratories; Materials Science; Nanocrystals; Nanotechnology; Optical and Electronic Materials; Porosity; Power factor; Single wall carbon nanotubes; Thermal conductivity; Thermoelectric materials
• ISSN: 1476-1122; 1476-4660; 1476-4660
• DOI: 10.1038/s41563-018-0217-z

Inorganic chalcogenides are traditional high-performance thermoelectric materials. However, they suffer from intrinsic brittleness and it is very difficult to obtain materials with both high thermoelectric ability and good flexibility. Here, we report a flexible thermoelectric material comprising highly ordered Bi 2 Te 3 nanocrystals anchored on a single-walled carbon nanotube (SWCNT) network, where a crystallographic relationship exists between the Bi 2 Te 3 < 1 ¯ 2 1 ¯ 0 > orientation and SWCNT bundle axis. This material has a power factor of ~1,600 μW m −1  K −2 at room temperature, decreasing to 1,100 μW m −1  K −2 at 473 K. With a low in-plane lattice thermal conductivity of 0.26 ± 0.03 W m −1  K −1 , a maximum thermoelectric figure of merit ( ZT ) of 0.89 at room temperature is achieved, originating from a strong phonon scattering effect. The origin of the excellent flexibility and thermoelectric performance of the Bi 2 Te 3 –SWCNT material is attributed, by experimental and computational evidence, to its crystal orientation, interface and nanopore structure. Our results provide insight into the design and fabrication of high-performance flexible thermoelectric materials. Bi 2 Te 3 materials suffer from brittleness, limiting their application for thermoelectric harvesting. By depositing ordered nanocrystals onto single-wall carbon nanotubes, a flexible material is formed that achieves ZT of 0.89 at room temperature.