Functionalization of two-dimensional phthalo-carbonitride with metal atoms

Two-dimensional (2D) carbonitrides have attracted intense interest because of their intriguing physical and chemical properties. One such 2D system is the so-called phthalo-carbonitride (pc-C₃N₂) with stoichiometry C₃N₂ and an extended network of phthalocyanine-like cores. Here we use first-principles calculations to study pc-C₃N₂ sheets with Al, Zn, or Cu atoms attached at the cores. We describe the structural details of various possible geometries and probe the electronic properties of the most stable configurations. The decorated sheets are metallic, with the exception of the Zn case, which is a semiconductor with a small energy band gap. Moreover, the Cu-laden monolayers bear finite magnetization. These key properties highlight the potential of C₃N₂-based 2D materials as multi-functional components in various applications.