Separation of Ultrahigh-Purity Long Semiconducting Carbon Nanotubes via Gel Chromatography

Mass production of ultrahigh-purity long semiconducting single-wall carbon nanotubes (s-SWCNTs) is essential for their utilization in high-performance carbon-based devices. Here, the separation of ultrahigh-purity long s-SWCNTs is achieved by integrating repeated short-duration ultrasonic dispersion with iterative separation via gel chromatography. The resulting s-SWCNTs are confirmed to have a purity exceeding 99.9999%, representing the highest purity achieved via surfactant-based separation methods. Additionally, the average length of the separated s-SWCNTs exceeds 430 nm, with ≈47% surpassing 400 nm in length—more than twice the length of those obtained through traditional dispersion and separation methods. From these, a subset of s-SWCNTs with an average length of ≈674 nm and 79.8% exceeding 400 nm is further extracted for fabricating SWCNT thin-film transistors. The resulting transistors exhibit markedly superior transport performance compared to those derived from s-SWCNTs produced via conventional methods, characterized by significantly higher on-state conductance of ≈149 µS µm⁻¹, higher carrier mobility of over 89.1 cm²V⁻¹s⁻¹ and a high on/off ratio exceeding 10⁵. The work demonstrates the exceptional separation capability of surfactant-based gel chromatography in producing ultrahigh-purity long s-SWCNTs with minimal defects, which holds significant promise for advancing the application of SWCNTs in high-performance electronic devices.