Direct functionalization of Mo₂CT<i> _x </i> MXene via single-step synthesis for printable, flexible, non-invasive moisture detection systems

Abstract A printable moisture sensor is an advanced device designed to measure water content in various materials, including soil, air, and other substances. The incorporation of K + functionalization significantly increases the material’s hydrophilicity, promoting more effective adsorption and desorption of water molecules. This study explores the impact of MXene functionalization on moisture sensing performance by examining the water adsorption behavior of both pure and K + -functionalized MXene-based sensors. Two different concentrations of K + -functionalized MXene, 1M and 3M, were investigated. The results demonstrated that the 3M K + -functionalized MXene exhibited better performance. These sensors demonstrated high sensitivity of 1.580 Δ R /%Δ relative humidity (RH) across a wide humidity range (20%–80% RH) and featured ultrafast response and recovery times of 2.5 s and 12.5 s, respectively. Furthermore, the Mo 2 CT x -based sensors not only achieve the broadest operational range but also set a new benchmark for MXene-based moisture sensor sensitivity, outperforming the current state-of-the-art. These remarkable properties establish Mo 2 CT x -based sensors as highly promising candidates for printable, flexible, and non-invasive moisture detection systems, enabling real-time environmental and industrial monitoring.