Fast response flexible humidity sensors based on TiCT MXene-heterostructures for multifunctional applications

High-performance humidity sensors with fast response and recovery capabilities are still a significant requirement in wearable digital healthcare applications. Herein, multifunctional humidity sensors based on heterostructured Ti 3 C 2 T x MXenes have been designed, and are endowed with greatly improved sensing performance compared with the Ti 3 C 2 T x sensors. The Ti 3 C 2 T x /SnO 2 sensor displays a high response of 13.4 and rapid response time (2 s) to 59% relative humidity (RH), good repeatability, a wide detection range for 11-97% RH, and high selectivity to water. Complex impedance spectroscopy and the synergistic effects of heterojunctions are employed to explain the mechanisms of the enhanced sensing performance of the Ti 3 C 2 T x /SnO 2 sensors. Such exceptional performance makes this Ti 3 C 2 T x /SnO 2 -based humidity sensor much more applicable for applications of real-time respiratory monitoring and non-contact measurements. This work provides effective strategies for humidity sensors for collecting biomedical signals and realizing non-contact human-machine interaction. The designed Ti 3 C 2 T x /SnO 2 humidity sensors are endowed with rapid response time and excellent sensing performance, which also display the great potential for the applications of real-time respiratory monitoring and non-contact measurements.