Room Temperature Gas Sensing of Two-Dimensional Titanium Carbide (MXene)

Wearable gas sensors have received lots of attention for diagnostic and monitoring applications, and two-dimensional (2D) materials can provide a promising platform for fabricating gas sensors that can operate at room temperature. In the present study, the room temperature gas-sensing performance of Ti₃C₂T_x nanosheets was investigated. 2D Ti₃C₂T_x (MXene) sheets were synthesized by removal of Al atoms from Ti₃AlC₂ (MAX phases) and were integrated on flexible polyimide platforms with a simple solution casting method. The Ti₃C₂T_x sensors successfully measured ethanol, methanol, acetone, and ammonia gas at room temperature and showed a p-type sensing behavior. The fabricated sensors showed their highest and lowest response toward ammonia and acetone gas, respectively. The limit of detection of acetone gas was theoretically calculated to be about 9.27 ppm, presenting better performance compared to other 2D material-based sensors. The sensing mechanism was proposed in terms of the interactions between the majority charge carriers of Ti₃C₂T_x and gas species.