Batch Fabrication of Ultrasensitive Carbon Nanotube Hydrogen Sensors with Sub-ppm Detection Limit

Carbon nanotube (CNT) has been considered as an ideal channel material for building highly sensitive gas sensors. However, the reported H2 sensors based on CNT always suffered from the low sensitivity or low production. We developed the technology to massively fabricate ultra-highly sensitive H2 sensors based on solution derived CNT network through comprehensive optimization of the CNT material, device structure, and fabrication process. In the H2 sensors, high semiconducting purity solution-derived CNT film sorted by poly[9-(1-octylonoyl)-9H-carbazole-2,7-diyl](PCz) is used as the main channel, which is decorated with Pd nanoparticles as functionalization for capturing H2. Meanwhile, Ti contacts are used to form a Schottky barrier for enhancing transferred charge-induced resistance change, and then a response of resistance change by 3 orders of magnitude is achieved at room temperature under the concentration of ∼311 ppm with a very fast response time of approximately 7 s and a detection limit of 890 ppb...