Novel cyclic BxCyHz nanorings: First-principles design and electronic tunability of unexplored boron–carbon hybrid nanostructures

Abstract

This study investigates cyclic boron–carbon–hydrogen (B${}_x$C${}_y$H${}_z$) isomers to assess their structural stability and potential as functional materials. A systematic enumeration satisfying $x+y=6$ yields 64 distinct structures. Electronic, thermodynamic, and optical properties were evaluated using density functional theory (DFT) at the GGA-PBE level, with vibrational analyses refined using the HSE06 hybrid functional. Energetic screening identifies 12 dynamically stable isomers with binding energies between $-0.34$ and $-0.16$ eV/atom and no imaginary frequencies. Band gaps span 0.399–5.169 eV (GGA-PBE) and 0.761–6.238 eV (HSE06), indicating broad electronic tunability. Gibbs free energy calculations using borane (BH${}_3$) and ethylene (C${}_2$H${}_4$) as precursors show favorable formation energetics ($\Delta G<0$) over 298–1000 K. Optical absorption extends from visible to ultraviolet (173–1527 nm). These results demonstrate that compositional variation enables systematic tuning of nanoring properties, supporting their potential for electronic, optical, and biomedical applications.