Highly sensitive and selective H2S sensors with ultra-low power consumption based on flexible printed carbon-nanotube-thin-film-transistors

Abstract

Flexible printed carbon-nanotube-thin-film-transistors (CNT-TFTs) with characteristics of low cost, low operating voltage, low power consumption, and signal amplification have great potential for emerging electronics powered by self-powered systems or low-power density thin-film solar cells. In this work, we have fabricated flexible printed CNT-TFTs using the printing process to selectively deposit semiconducting CNTs in device channels as channel materials, printed silver electrodes as side gates, and printed ion gel as the dielectric layer. The as-prepared TFTs exhibited an extremely high sensitivity to H2S (up to 1565% ppm-1) at room temperature (25 ℃) and the relative humidity (RH) of 5%, excellent signal amplification (response increased from 1% to 4045.5% towards 2 ppm H2S), ultra-low working power consumption (1.03 nW under 2 ppm H2S), excellent selectivity, fast response/recovery time (10 s/26 s) and great mechanical flexibility (stable after 10,000 times bending with 5 mm radius). The outstanding improvement of sensor characteristics was related to the enrichment and absorption of H2S by ionic liquids, and the resistor-mode device's response to 2 ppm H2S increased from ~1% to 80% after the device channel was covered by ion gel. To the best of our knowledge, our H2S sensors demonstrated the recorded low power consumption (1.03 nW) and high response (4045.4%) when exposed to 2 ppm H2S at room temperature, making our sensors a promising candidate for portable applications in gas detection.