Flexible polymer/multi-walled carbon nanotube composite films for thermoelectric generators

Abstract

Organic and flexible thermoelectric generators (TEGs) have attracted increasing interest in energy harvesting applications. In this work, PET films were dipped into functionalized multi-walled carbon nanotube (MWCNT) incorporated the ethylene-octene copolymer (EOC) solution. Benefited from the flexible and sticky substrate of the coated layers, TE prototype composed six junctions easily connected in series with the copper connections has been fabricated to demonstrate generated voltage between hot and cold sides. Seebeck coefficient of KMnO4 and HNO3 treated nanotubes was 19.4 μV/K and 34.8 μV/K, respectively, while pristine legs exhibited only 12.3 μV/K. The maximum output power from the prototype was 1.82 nW upon the application of a 20 K temperature gradient with the load resistivity of 18 kω. It is revealed that TE properties were enhanced by simple functionalization resulting in thermoelectric power on relatively the same order as single-walled carbon nanotube (SWCNT)/polymer composites, but using almost seven times much cheaper MWCNTs. We hope the present study provides a new path to low-grade energy required TE materials with their simple production and significant low-cost properties. © 2019 Author(s).