Versatile Soluble Iron Oxide‐Based Monolayers With Ultrahigh Two‐Dimensional State Stability

Owing to the quantum confinement effect, atomically thin two-dimensional (2D) materials exhibit many exceptional physical properties that are closely related to their atomically thin structure, rendering them extraordinary application potential across diverse fields. However, maintaining their 2D state stability in versatile systems has been a challenge for their practical applications. Here, we report a facile coordination-substitution strategy to synthesize iron oxide-based (FeO-NHR, NHR = primary amine) monolayers with large lateral dimensions and high crystallinity. Benefiting from sufficient and tunable coordinated functional groups, the FeO-NHR monolayers feature good solubility in low-polarity solvents along with ultra-high 2D state stability. By changing the coordination with oxygen-rich organic ligands, the as-obtained FeO-NHR monolayers exhibit good water solubility and biocompatibility, and show superior antibacterial activity under light irradiation in the presence of hydrogen peroxide. Our findings provide a robust FeO-based 2D platform with tailorable solubility and ultra-high 2D state stability, offering new insights for the rational design of other reliable solution-processable 2D materials.