Computational Design of 2D Nanoporous Graphene via Carbon-Bridged Lateral Heterojunctions in Armchair Graphene Nanoribbons

The interest in two-dimensional (2D) carbon allotropes arises from their ability to alter their properties based on the atomic topology employed, which can significantly affect their electronic properties and benefit advancements in new technologies. This work presents a new nanoporous graphene (NPG) allotrope obtained through lateral heterojunctions via pairs of trivalent sp² carbon atoms of armchair graphene nanoribbons (AGNRs). These pairs were used as linkers between AGNRs to achieve this structure, forming connections that enhance the porous architecture. This novel planar and porous 2D carbon allotrope integrates some structural and electronic advantages of AGNRs into a 2D framework. Composed of 3-, 6-, and 12-membered carbon rings, the NPG was investigated using density functional theory (DFT) calculations and ab initio (AIMD) and classical molecular dynamics (CMD) simulations to explore its structural, electronic, and mechanical properties. Among the results presented, we show that the material demonstrates high dynamical and thermal stability at 1000 K. Furthermore, the NPG exhibits metallic and nonmagnetic behavior and is achieved by transitioning from the semiconducting nature of some AGNRs to a metallic 2D carbon system. The elastic properties reveal the material's distinct response to applied strain, with fractures occurring in the nanoribbon segment along the <i>x</i>-direction. However, fractures are observed in the C-C bonds involved in the heterojunction region in the <i>y</i>-direction. The calculated Young's modulus ranges from 394 to 690 GPa, which is lower but comparable to graphene. The formation energy of NPG decreases with increasing width of the AGNRs used to compose the 2D material, indicating enhanced stability for wider nanoribbons. These findings highlight the potential of NPG for applications in nanoelectronics and advanced new technologies.