Effect of Surfactants on the Thermoelectric Performance of Double‐Walled Carbon Nanotubes

Thermoelectrics are a promising solution to the recovery of some 60% worldwide energy wasted as heat. However, their conversion efficiency is low and best performing materials brittle, toxic, made expensive ceramics. The challenge in developing better disrupting electrical vs thermal conductivity correlation, achieve simultaneously with high conductivity. Carbon nanotubes allow for decoupling electronic density states from phonon this paper shows that flexible, thin films double‐walled carbon nanotube (DWCNT) can form effective n‐ p‐doped semiconductors combined Seebeck coefficient 157.6 µV K −1 , highest reported single DWCNT device date. This achieved through selected surfactant doping, whose role correlated length hydrocarbon chain hydrophobic tail group surfactant’s molecules. CNTs functionalized Triton X‐405 show output power consisting junction p‐ n‐type thermoelectric elements, reaching 67 nW 45 temperature gradient. Thus enabling cheaper, more efficient generators use CNTs.