High-performance printed diodes based on large-diameter semiconducting carbon nanotubes for flexible electronics

The presence of both metallic (M–) and semiconducting (S–) single-walled carbon nanotubes (SWCNTs) in as-synthesized samples severely limits their application in flexible electronics, where the efficient separation of large-diameter (>1.2 nm) semiconducting tubes and the preparation of low-temperature-compatible inks pose key challenges. This study proposes a fully integrated ‘material → ink → device’ solution. First, by optimizing the NaOH concentration (0.3 mmol l−1), the coating state of sodium dodecyl sulfate (SDS) was modulated, enhancing the separation selectivity of large-diameter S-SWCNTs via gel chromatography (GC). Second, a ‘filtration → washing → exchange’ process was designed to successfully transfer the S-SWCNTs into an organic ink based on a low-decomposition-temperature surfactant (poly(propylene carbonate), PPC), making it compatible with low-temperature aerosol-jet printing. Finally, a fully printed Ag-SWCNT-Pt Schottky diode was realized using this ink. The device exhibits excellent electrical performance: a rectification ratio of up to 104, a subthreshold swing of 65–68 mV dec−1, and a Schottky barrier height of approximately 0.38 eV. This work provides a feasible material foundation and process route for high-purity separation, low-temperature printing, and high-performance flexible electronic integration of large-diameter S-SWCNTs.