Abstract
Thermoelectric (TE) materials and devices have attracted great attention due to their ability to convert waste heat to electrical power and active cooling. However, the conventional bulk TE materials are inorganic semiconductors with inherent brittleness and rigidity. They cannot closely contact curved heat sources and sinks, which limits their application in modern electronics. It remains a big challenge to fabricate high-performance TE materials and devices with good flexibility. Here, we report a flexible TE device comprised of a single wall carbon nanotube (SWCNT) network and (000l)-textured Bi2Te3 nanocrystals prepared by a magnetron sputtering technique. The unique Bi2Te3-SWCNT hybrid structure has a TE figure of merit (ZT) value of ∼0.23 at ∼330 K. A prototype TE device made of this hybrid gives a maximum output power density of ∼0.93 mW cm−2 under a temperature difference of 25 K at ambient temperature and shows good flexibility under bending. Our results open up a new way to the development of flexible TEs and their application in self-powered portable devices.