Computational Design of Three-Dimensional Nitrogenated Holey Graphene Structures with Phase-Dependent Optoelectronic Properties.

In this work, we propose and comprehensively characterize two novel three-dimensional nitrogenated holey graphene (3D-NHG) structures, designated as the α and β phases. These architectures are predicted through a computational protocol based on the controlled compression of stacked 2D-NHG monolayers. Their dynamical and structural stabilities are assessed via phonon dispersion calculations and molecular dynamics simulations within the density-functional tight-binding framework. Density functional theory calculations reveal that the α phase is a semiconductor with an indirect HSE06 bandgap of 0.87 eV, whereas the β phase exhibits a zero-gap semiconducting character. Furthermore, optical calculations reveal strong absorption in the ultraviolet region, with negligible absorption throughout the visible range. These findings highlight the potential of 3D-NHG architectures as a versatile platform for tailoring the electronic and optical properties of carbon nitride frameworks for future optoelectronic applications.