Highly stretchable organic thermoelectrics based on dispersion-stable and dry-transferable single-walled carbon nanotubes

Organic thermoelectrics (TEs) based on carbon nanotubes (CNTs) has emerged as promising energy-harvesting and sensing technologies for soft/wearable TEs. However, the dispersion-instability and limited processability of CNTs have been drawbacks for their solution-processing and versatile device applications. Herein, we report a post-treatment method improving the TE performance and enabling stretchable device applicability of singlewalled CNT (SWCNT) and carboxymethyl cellulose (CMC) composite with excellent dispersion-stability. The post-treatment with H2SO4 induces the elimination of CMC polyelectrolyte through acid hydrolysis, which enhances the electrical conductivity (6) and thus, power factor of SWCNT/CMC films. The post-treatment with polyethyleneimine leads to n-type TE feature with decent 6 from the H2SO4-treated p-type films. Moreover, the patterned p-/n-type films, prepared on elastic substrates via a chemically-controlled transfer technique, possess outstanding TE durability with high stretchability. We finally demonstrated SWCNT-based TE generators providing stable output characteristics under highly stretched conditions. This work can offer insights to develop easy-processable and highly stretchable TE materials/devices.