In-Situ Surface Polymerization of Swcnt/Pani Bilayer Film: Effective Composite for Improving Seebeck Coefficient and Power Factor

Abstract

Flexible thermoelectric composites are promising in harvesting low temperature wasted energy and have a wide range of applications in wearable devices. However, the uncontrollable interfaces between the components significantly scatter the transport of hot electrons and lead to a reduced thermoelectric performance. In this research, we directly prepare polyaniline (PANI) on the surface of a super-conductive SWCNT film, via in-situ surface polymerization, to control the interfacial filtering effect and preserve the high conductivity of the SWCNT film. It is found that the polymerization process could easily tune the interfaces between the SWCNT film and the PANI. Under optimal conductions, a SWCNT/PANI bilayer composite exhibits a Seebeck coefficient of 26  and a power factor of 89 . The Seebeck coefficient is twofold increase compared to a pure SWCNT film, while the power factor is three times of the value from a pure SWCNT film and 500 times of that from a solution-mixed SWCNT/PANI composite. The enhanced thermoelectric performance could be attributed to the factors that SWCNT assisted growth and the  interaction promote the formation of an oriented and compacted PANI layer that possesses a high Seebeck coefficient, and the bilayer structure could also maximally maintain the electrical conductivity of the SWCNT in the composite. The bilayer composite has then been investigated as an energy harvester and a temperature sensor, and its reliable performance indicates the potential of the SWCNT/PANI bilayer structure in wearable applications.