Synthetic carbon allotropes are fascinating for their outstanding properties and potential applications. Scientists have devoted decades to synthesizing new types of carbon materials. However, a two-dimensional fullerene, which possesses a unique structure, has not been successfully synthesized until now.

A research group led by Prof. Zheng Jian from the Institute of Chemistry of the Chinese Academy of Sciences (ICCAS) developed a new interlayer bonding cleavage strategy to prepare a two-dimensional monolayer polymeric fullerene.

The researchers prepared magnesium intercalated C₆₀ bulk crystals as the precursor to the exfoliation reaction. They then utilized a ligand-assisted cation exchange strategy to cleave the interlayer bonds into bulk crystals, which led to the bulk crystals being exfoliated into monolayer nanosheets.

The structure of monolayer polymeric C₆₀ was explored by single crystal X-ray diffraction and scanning transmission electron microscopy (STEM). In this monolayer polymeric C₆₀, cluster cages of C₆₀ are covalently bonded with each other in a plane, forming a regular topology that is distinct from that of conventional 2D materials.

Furthermore, the monolayer polymeric C₆₀ exhibits an interesting in-plane anisotropic property and a moderate bandgap of 1.6 eV, which makes it a potential candidate for use in electronic devices.

“The work is the first to synthesize a monolayer polymeric fullerene. It is of great significance, as it adds a new member to the carbon material family,” Zheng said. “This work has opened up a new research field in two-dimensional carbon material areas and the synthesis strategy could provide a unique perspective in exploring new carbon material.”

The study, entitled “Synthesis of a monolayer fullerene network,” was published in Nature.