Layer-by-Layer Assembly of Two-Dimensional Materials: Meticulous Control on the Nanoscale

Two-dimensional (2D) materials such as graphene, MXenes, and transition-metal dichalcogenides have recently gained substantial attention for their superlative physicochemical properties. Assembling 2D materials into functional composites is of great importance, which could be the key to breakthroughs in emerging technologies and applications. The layer-by-layer assembly technique is a powerful, versatile, facile, and potentially highly scalable processing tool that has successfully been demonstrated to bring unique materials system advantages to various fields such as energy storage, chemical sensors, nanofiltration membranes, and solar cells. The wide range of precursors (e.g., polyelectrolytes) and tuning parameters that facilitate the incorporation of nanostructured materials makes this technique particularly compelling for creating 2D-material-based composites with ordered structure and tunable material properties. In this review, we highlight the exciting works in the field that utilize 2D materials implemented in layer-by-layer assembled composites. We also discuss the challenges and opportunities toward industrialization of layer-by-layer assembled composites with perspectives on future research directions.