High‐Performance Paper‐Based Humidity Sensor with Self‐Assembling 3D Composite Structure Utilizing MXene‐Functionalized Graphene Oxide Strategy for Wearable Medical Monitoring

Abstract In the field of health monitoring, there is an increased requirement for humidity sensing that can achieve a balance among high‐performance detection, wearability, and environmental sustainability. Current humidity sensing often does not perform well enough due to the insufficient available adsorption sites for water molecules within the sensing layer and the lack of effective transmission paths. Herein, this study leverages the Ti─O─C bond at the MXene (Ti ₃ C ₂ T _x )‐graphene oxide (GO) interface to drive the spontaneous formation of a 3D configuration with an enhanced specific surface area. The 3D MXene@GO configuration exhibits an overall morphology characterized by surface with micro‐wrinkles. The MXene@GO composite sensing layer is successfully synthesized on rice paper‐based interdigital electrode substrate through a facile dip‐coating process. This 3D architecture is expected to increase water molecule adsorption sites, improve transmission pathways, thereby obtaining enhanced moisture‐sensitive properties. By optimizing the process parameters, the sensor exhibits outstanding mechanical flexibility and superior response/recovery characteristics (36.306 s/21.376 s, from 22 to 98 %RH). The proof‐of‐concept demonstrations for continuous human respiratory pattern analysis and wound exudate level assessment further validates its potential in wearable biomedical scenarios.