High-performance flexible fully-printed all-carbon thin film transistors and ultrasensitive NH3 sensors

Abstract

In this paper, we developed a new method to construct flexible fully-printed all-carbon thin film transistors (TFTs) with excellent properties and highly sensitive ammonia (NH₃) sensors via aerosol jet printing. Here, sorted semiconducting single-walled carbon nanotubes (sc-SWCNTs), carboxyl-functionalized single-walled carbon nanotubes (P₃ SWCNTs) and printed ion gels were chosen as channel materials, printed source, drain and side-gate electrodes, and dielectric layers. Flexible printed side-gate TFTs showed high on/off ratios (∼10⁶), good mobility (up to 9.8 cm² V⁻¹ s⁻¹), low hysteresis and small subthreshold swings (∼80 mV dec⁻¹) at gate voltages of ±1 V. As-prepared TFTs exhibited an extremely high response to NH₃ (up to 346.73% within 11 s) with good selectivity, ultralow limit of detection (LOD) (21.35 ppb) and low power consumption (0.49 nW) at room temperature due to the strong adsorption and enrichment of NH₃ gas by ionic liquids (ILs) in the ion gels and the signal amplification of printed ion-gel TFTs. Furthermore, all devices can withstand 10 000 times bending with a radius of 5 mm, displaying good mechanical flexibility due to the high mechanical properties of carbon nanotubes.