Designing MXene-Based Chemical Sensors Using Intercalation Chemistry and Surface Modification

The demand for room-temperature chemical sensing has been increasing due to the emergence of flexible, portable, and low-power devices. To achieve this, two-dimensional (2D) nanomaterials have drawn attention due to their high surface area, and high tunability, and ability to detect molecules at room temperature. MXenes, a large class of 2D transition metal carbides/nitrides with interesting properties, are one of the most recent group of nanomaterials to be utilized as sensing materials. By exploiting the simultaneous existence of metallic-like electrical conductivity and high-density surface functional groups, we were able to previously demonstrate that Ti₃C₂ MXene sensors show an exceptionally high single-to-noise ratio. Here, the fabrication of laminated MXene thin films and our strategies to apply them as tunable chemical sensors will be suggested, with special focuses directed at methods to utilize the intercalation and surface chemistry of MXene laminates. We demonstrate that by deliberately intercalating cations into the interlayers of MXene laminates, the gas response and selectivity were greatly enhanced compared to gas sensors based on pristine MXene films. Also, we show that modifying the surface functionalities of MXene can be utilized to enhance molecule detection.