Pseudo Jahn–Teller Origin of Buckling Distortions in Two-Dimensional Triazine-Based Graphitic Carbon Nitride (g-C₃N₄) Sheets

Abstract

Due to its direct band gap and light mass, the recently synthesized triazine-based, graphitic carbon nitride (TGCN) is considered a promising material for future microelectronics. However, despite the structural similarity with completely planar carbon-only graphene, TGCN sheets are different because of the presence of buckling distortions making the TGCN sheets nonplanar. In this article, we show that the sufficiently strong coupling between the unoccupied molecular orbitals (UMOs) with occupied molecular orbitals (OMOs) leads to pseudo Jahn–Teller distortions (PJT) and consequent buckling of TGCN layers. Doping the TGCN with doubly charged cations such as Be2+ can suppress the PJT distortions resulting in a completely planar structure. A proper understanding of the mechanism of the PJT effect in TGCN is crucial for tailoring properties that are relevant for practical applications.

Topochemical Transformations of CaX2 (X=C, Si, Ge) to Form Free‐Standing Two‐Dimensional Materials

“…Closely spaced relevant occupied and unoccupied molecular orbitals that might vibronically couple along the b 2g distortion (the buckling mode) has been shown to be the origin of lowering of symmetry of Si 6 H 6 and Ge 6 H 6 from their planar D 6 h to puckered D 3 d point group 9. Similar lowering of symmetry has also been reported for larger two‐dimensional fragments of s‐triazenes 37. Nevertheless, intercalation of Ca II within the silicene layers is shown to quench the PJT distortion in the B(h) phase, thereby making the Si 6 rings perfectly planar (Figure 2 a,b).…”

Stability, electronic, and optical properties of two‐dimensional phosphoborane

“…To analyze the chemical bonding pattern of the 2D‐B 4 P 2 sheet, the solid‐state adaptive natural density partitioning (SSAdNDP) algorithm was used . Previously it was shown that SSAdNDP is a powerful tool for analyzing chemical bonding in two‐dimensional periodic systems . A plane wave (PW) calculation was performed using 450 eV energy cut off with convergence threshold 10 −6 eV for total energy.…”

Graphitic carbon nitride‐chitosan composites–anchored palladium nanoparticles as high‐performance catalyst for ammonia borane hydrolysis

“…has attracted great interest. This is because of its unique chemical properties including large specific surface area, high adsorption capacity, and good electron conductivity, as well as its low price and good stability . Moreover, its nitrogen richness facilitates anchoring metal NPs …”

“…This is because of its unique chemical properties including large specific surface area, high adsorption capacity, and good electron conductivity, as well as its low price and good stability. 14,15 Moreover, its nitrogen richness facilitates anchoring metal NPs. 16 Compared with most of the other noble metals, the low-cost Pd catalysts exhibit similar or even better catalytic activity in many heterogeneous catalytic reactions.…”