Iptycene-Assisted Alignment of Chirality-Sorted SWCNTs for Field-Effect Transistors

Single-walled carbon nanotubes (SWCNTs) are ideal channel material candidates for energy-efficient nanoscale transistors; however, it is challenging to achieve uniform alignment of semiconducting SWCNTs with homogeneous chirality. Here, we report the proof-of-concept of using organized chirality-sorted SWCNTs via the alignment relay technique (ART), where iptycene molecules order the nanotubes through π–π interactions. Top-gated field-effect transistors (FETs) were fabricated with aligned (10,3) chirality SWCNTs as channels to show an ION of 3.8 μA, an ION/IOFF ratio of 2.9 × 106, and a carrier mobility of 10.08 cm2/(V s), which is enhanced by two magnitudes of order compared with a bundled SWCNT network channel. In addition, the ART was applied to align commercially available semiconducting SWCNTs to fabricate a chemiresistive gas sensor that showed prompt detection of 4 ppm ammonia (NH3) with a sensitivity of 0.43 ± 0.04%/ppm, demonstrating a general approach to align SWCNTs for applications in electronic devices.