Wafer-Scale Lateral Self-assembly of Mosaic Ti3C2Tx (MXene) Monolayer Films

Abstract: Bottom-up assembly of two-dimensional (2D) materials into macroscale morphologies with emergent properties requires control of the material surroundings, so that energetically favorable conditions direct the assembly process. MXenes, a class of recently developed 2D materials, have found new applications in areas such as electrochemical energy storage, nanoscale electronics, sensors, and biosensors. In this report, we present a lateral self-assembly method for wafer-scale deposition of a mosaic-type 2D MXene flake monolayers that spontaneously order at the interface between two immiscible solvents. Facile transfer of this monolayer onto a flat substrate (Si, glass) results in high-coverage (>90%) monolayer films with uniform thickness, homogeneous optical properties, and good electrical conductivity. Multiscale characterization of the resulting films reveals the mosaic structure and sheds light on the electronic properties of the films, which exhibit good conductivity over cm-scale areas.