Enhanced and engineered d0 ferromagnetism in molecularly-thin zinc oxide nanosheets

Molecularly-thin nanosheets are ultimate two-dimensional (2D) nanomaterials potentially giving unusual physical and chemical properties due to the strong 2D quantum and surface effects. Here, it is demonstrated that 1.5-nm-thick ZnO nanosheets exhibit greatly enhanced room-temperature ferromagnetism. Saturation magnetization value of the nanosheets with intercalated dodecyl sulfate layers is approximately 100 times that of ZnO mesocrystals. Anion exchange with dodecyl phosphate layers strongly suppresses ferromagnetic ordering as a result of surface defect passivation while maintaining bulk-like n-type semiconducting properties, which reveals significance of interfacial states to engineer functional properties of nanosheet-based hybrid materials. Dense integration of interfacial ferromagnetic centers in the lamellar structure gives enhanced ferromagnetism to ZnO nanosheets. Anion exchange with dodecyl phosphate layers strongly suppresses ferromagnetic ordering as a result of surface defect passivation while maintaining bulk-like n-type semiconducting properties.