Printed thin-film transistors and NO2 gas sensors based on sorted semiconducting carbon nanotubes by isoindigo-based copolymer

Abstract

In this work, a new poly(9,9-dioctylfluorene) (PFO) derivative (named PFIID) with the large conjugated planar surfaces was designed and synthesized, and the ability to sort sc-SWCNTs was investigated in detailed. The absorption spectra of sorted SWCNT solutions demonstrated that PFIID exhibited the ability to selectively and efficiently sort sc-SWCNTs from commercial arc discharge carbon nanotubes. The underlying separation mechanism was studied with the aid of photoluminescence excitation (PLE) spectra and the molecular dynamic simulation. It was found that the simulation results agreed well with the experimental data. PFIID-sorted sc-SWCNTs were acted as the channel materials to construct printed thin-film transistors (TFTs) and nitrogen dioxide gas sensors. Printed SWCNT TFTs exhibited superior performance with good uniformity, high on/off ratios (∼106), high effective hole mobility (∼29.8 cm2 V−1 s−1) and small subthreshold swing (SS) (142–163 mV/dec) at low operating voltage (±2 V). NO2 gas sensors also showed good performance with high sensitivity (ΔR/Ro∼96%), fast response (30 s), good stability and the recovery time of 30 s when exposed to 60 ppm NO2 at room temperature. Both of the sensitivity and recovery time are one of the best performances reported for NO2 gas sensors at room temperature.