Scalable fabrication of a Ti3C2Tx-MXene@graphene-based humidity sensor via MILD etching and interfacial self-assembly

Among 2D nanomaterials, graphene and MXenes have attracted considerable interest for sensing applications owing to their large surface area, outstanding electrical properties and abundance of active sites. In this work, humidity sensors based on Ti 3 C 2 T x -MXene@Graphene heterostructure system were fabricated. Graphene was synthesized using a liquid-phase shear exfoliation method, while Ti 3 C 2 T x -MXene was prepared via the minimally intensive layer delamination method. Thin films of heterostructure nanosheets were deposited in one step using an interfacial self-assembly fabrication approach. Structural and morphological analyses confirmed the formation of uniform and continuous heterostructure thin-films. The heterostructure-based sensor exhibits an enhanced humidity response compared to sensors based on bare Ti 3 C 2 T x and graphene layers, with measured sensitivities of 27.53%, 7.67% and 4.46%, respectively, over a RH range of 20-80% at room temperature. The response and recovery times were 29 s and 20 s, respectively. The influence of the number of deposited heterostructure layers on the humidity response was also investigated. In addition, the sensor demonstrated good repeatability, acceptable long-term stability, and effective performance in real-time human breath monitoring. This study highlights the potential of interfacial self-assembly for fabricating MXenes-based heterostructures for humidity sensing applications. • Rapid, eco-friendly solution-based fabrication of 2D material heterostructures. • HRTEM-FIB cross-sections reveal spontaneous nanosheet interactions—overlap, stacking, and collisions—forming uniform monolayers. • MXene@Graphene hybrid layers exhibit a strong synergistic effect, boosting sensing performance. • Devices show excellent potential for environmental humidity detection and non-invasive human breath monitoring.