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Stacking-Tunable Electronic Properties in Recently Synthesized Hydrogen-Substituted Graphdiyne

Guilherme S. L. Fabris, Raphael B. de Oliveira, Bruno Ipaves, Marcelo L. Pereira Junior, Douglas S. Galvao

Abstract

Recent progress in porous carbon materials has highlighted the importance of structural design in controlling emergent physicochemical properties. In this context, hydrogen-substituted graphdiyne (HsGDY), a three-dimensional framework derived from graphdiyne (GDY), has recently emerged as a promising architecture whose stacking-dependent behavior remains largely unexplored. Here, we present a comprehensive first-principles investigation of the structural, electronic, and optical properties of HsGDY across distinct stacking sequences. Our results identify the AA and ABC configurations as the most energetically favorable, with AA corresponding to the global minimum, consistent with recent experimental observations. Electronic-structure analysis reveals that HsGDY is an indirect semiconductor with an electronic band gap of 0.89 eV (optB88-vdW), primarily governed by interlayer coupling and van der Waals interactions. The optical response exhibits pronounced absorption features spanning the visible to ultraviolet regions, highlighting strong potential for optoelectronic applications. \textit{Ab initio} molecular dynamics (AIMD) simulations at 700 K confirm the thermal robustness of the framework, with negligible structural distortions. Collectively, these findings elucidate the stacking-dependent stability and semiconducting character of HsGDY, providing a solid theoretical foundation for its integration into next-generation nanoelectronic and energy-harvesting technologies.

Stacking-Tunable Electronic Properties in Recently Synthesized Hydrogen-Substituted Graphdiyne

Abstract

Recent progress in porous carbon materials has highlighted the importance of structural design in controlling emergent physicochemical properties. In this context, hydrogen-substituted graphdiyne (HsGDY), a three-dimensional framework derived from graphdiyne (GDY), has recently emerged as a promising architecture whose stacking-dependent behavior remains largely unexplored. Here, we present a comprehensive first-principles investigation of the structural, electronic, and optical properties of HsGDY across distinct stacking sequences. Our results identify the AA and ABC configurations as the most energetically favorable, with AA corresponding to the global minimum, consistent with recent experimental observations. Electronic-structure analysis reveals that HsGDY is an indirect semiconductor with an electronic band gap of 0.89 eV (optB88-vdW), primarily governed by interlayer coupling and van der Waals interactions. The optical response exhibits pronounced absorption features spanning the visible to ultraviolet regions, highlighting strong potential for optoelectronic applications. \textit{Ab initio} molecular dynamics (AIMD) simulations at 700 K confirm the thermal robustness of the framework, with negligible structural distortions. Collectively, these findings elucidate the stacking-dependent stability and semiconducting character of HsGDY, providing a solid theoretical foundation for its integration into next-generation nanoelectronic and energy-harvesting technologies.
Paper Structure (8 sections, 2 equations, 5 figures)

This paper contains 8 sections, 2 equations, 5 figures.

Table of Contents

  1. Methodology
  2. Results and Discussion
  3. Crystal Structure and Stacking Configurations
  4. Energy Landscape
  5. Dynamical and Thermal Stability
  6. Electronic Structure
  7. Optical properties
  8. Conclusion and perspectives

Figures (5)

  • Figure 1: Optimized structures of $\alpha$-GDY and HsGDY, highlighting the hexagonal in-plane lattice defined by the $\vec{a}$ and $\vec{b}$ vectors, together with the AA, AB, and ABC stacking registries. Distinct colors label layers A, B, and C to emphasize the relative lateral offsets that differentiate the stacking sequences.
  • Figure 2: HsGDY Energies. (a) Binding energy per atom for AA, AB, and ABC stacking sequences, highlighting the near degeneracy between AA and ABC and the reduced stability of the AB registry. (b) Cohesive energy per atom for graphite, diamond, $\alpha$-GDY, and HsGDY, positioning the hydrogenated framework within the stability spectrum of carbon allotropes.
  • Figure 3: Phononic band structure of bulk HsGDY.
  • Figure 4: Electronic band structures and the corresponding projected density of states of: (a) monolayer $\alpha$-GDY and: (b) AA-stacked bulk HsGDY. The shaded region highlights the band gap, while the PDOS identifies the orbital contributions near the band edges.
  • Figure 5: Optical absorption coefficient, refractive index, and reflectance of HsGDY for the 30-atom unit cell along the $x$, $y$, and $z$ directions. Dashed vertical lines indicate characteristic transition energies.