Flexible layer-structured Bi2Te3 thermoelectric on a carbon nanotube scaffold

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.