Environmentally Robust Semiconducting Carbon Nanotube Extraction with Cellulose Acetate in Polar Solvents

Abstract

Semiconducting carbon nanotubes (CNTs) are recognized as candidates for next-generation electronics and energy applications, where scalable and reproducible post-synthesis extraction of semiconducting CNTs is still required. In this study, purifying semiconducting CNTs using cellulose acetate (CA) as a surfactant in polar organic solvents is proposed that can tolerate environmental impurities such as water. Dispersion experiments with up to 1 v/v% water added to the polar organic solvent showed no significant deterioration in the purity and yield of the semiconducting CNTs. This process requires no dry hydrophobic solvents, in contrast to widely used extraction methods with conducting polymers. Controlling the solubility of CA with an ethyl lactate-tetrahydrofuran mixture helped differentiate between the colloidal stabilities of semiconducting and metallic CNTs and increased the purity of semiconducting CNTs. The semiconducting CNTs purified in this study demonstrated significant conductivity switching characteristics in electric double-layer transistors and large thermoelectric power factors used for thermal-electrical energy conversion. This study lays the groundwork for bridging the gap between the material preparation stages and practical applications of semiconducting CNTs.