Realization of Near-Room-Temperature Superparamagnetism in Graphene Quantum Dots by High-Concentration Semi-Ionic Fluorine Functionalization

Inducing room-temperature superparamagnetism in graphene quantum dots (GQDs), which can afford them various applications in nanoscale spintronic devices and quantum-information devices, remains a challenge due to the difficulty in atomically accurate fabrication of magnetic zigzag edges. Here, we report the realization of superparamagnetism in GQDs by high-concentration semi-ionic fluorine functionalization on the basal plane of GQD sheets. The functionalized GQDs with an average size of about 2.67 nm and a semi-ionic fluorine concentration as high as up to 18.3 atom % exhibit clear superparamagnetism with nearly zero coercivity and remanence magnetization and a near-room-temperature Curie temperature of 275 K. Our findings highlight the effectiveness of semi-ionic fluorine functionalization in inducing superparamagnetism in GQDs.