The rapid and dense assembly of solution-processed single-wall carbon nanotube semiconducting films via an acid-based additive in the aqueous dispersion

Abstract

The rapid and dense assembly of solution-processed single-wall carbon nanotube (SWCNT) semiconducting films is the key enabling factor for their practical applications to large-area electronics and potentially, roll-to-roll based process development. In this study, we demonstrate a significant reduction in the assembly time for a commercial nanotube dispersion (95%-purified semiconducting SWCNT ink), whilst maintaining a high-quality film with better density, by adding a ∼0.1% volume ratio of nitric acid to the dispersion. A rapidly and densely assembled film was formed after deposition for less than 30 seconds, compared to more than several minutes in a commercial reference ink as previously reported by many research groups. The relationships among the zeta potential, pH concentration, and deposition time of the engineered dispersion were also investigated. The electrostatically weakened force of the ionic surfactants in the engineered inks leads to the rapid formation of densely packed SWCNT films, thereby enabling the fabrication of high-performance SWCNT thin film transistors (TFTs) with a field-effect mobility of 18.80 ± 2.08 cm² V⁻¹ s⁻¹ and on/off ratios of ≥10⁴ in a significantly reduced process time.