Long-Alkyl-Chain Phosphonium Surfactant Molecular Wrapping to Block Oxygen Impurities in n-Type Carbon Nanotubes for Thermoelectric Applications

In several electronics applications, the instability of components containing n-type carbon nanotubes (CNTs) to atmospheric oxidation in harsh environments or high temperatures is a significant concern. Here, we reported that a dense molecular wrapping of n-type CNTs with phosphonium salts reduced the exposed CNT surface by 79% and suppressed the electrophilic reaction of oxygen on the CNT surface. After aging at 353 K for 28 days, 89% of its initial thermoelectric power factor was retained (290.3 μW m–1 K–2). This opens new avenues for the use of n-type materials in high-temperature electronics.