Antiferromagnetism in Two-Dimensional Polyradical Nanosheets

Two-dimensional (2D) organic magnetic materials have great value for research and applications in spintronics. However, unlike the diverse inorganic materials, finding 2D organic magnetic materials is still a major challenge. In this work, freestanding 2D organic magnetic polyradical (OMP) nanosheets were successfully synthesized using the polymerization of tris(2,3,5,6-tetrachloro-4-ethynylphenyl)methyl radicals at a liquid/liquid interface. The OMP obtained has a 2D sheet-like morphology and possesses triarylmethyl radicals after polymerization, which can act as spin centers. With the magnetic exchange coupling between radicals, the OMP shows an antiferromagnetic behavior with a Neel temperature of 42.5 K. Besides the OMP, this discovery also provides a route for synthesis of other potential antiferromagnetic 2D organic materials, which can act as essential building blocks in 2D organic spintronic devices.