Molecular Engineering of Octathio[8]Circulenes with Superhalogens for Enhanced Optoelectronic Properties

ABSTRACT Sunflower‐like octathio[8]circulene (C 16 S 8 ) has gained attention for its exceptional thermal and electronic properties. In this study, a superhalogen‐based doping strategy was employed to enhance its nonlinear optical (NLO) response, investigated through density functional theory (DFT) simulations. Superhalogens are chemical species with electron affinities surpassing those of conventional halogens, were selected from Group IIIA elements, specifically AlF 4 and BF 4 , for functionalization of C 16 S 8 . The resulting doped complexes exhibited notable thermal stability, as confirmed by high interaction energies. Comprehensive electronic structure analyses, including Natural Bond Orbital (NBO) charge distribution, vertical ionization energies, and HOMO‐LUMO energy gaps, indicated pronounced charge transfer and significant modulation of molecular orbital energies upon doping. Noncovalent interaction (NCI) analysis corroborated the existence of stabilizing noncovalent forces within the doped systems. The enhanced NLO behavior was further elucidated using the two‐level model, highlighting the role of excitation energy, oscillator strength, and excited‐state dipole moments. UV–Vis spectral analysis revealed a distinct bathochromic shift upon doping, indicating changes in electronic transitions. Among the systems studied, AlF 4 @C 16 S 8 exhibited the highest first‐order hyperpolarizability (1.59 × 10 4 a.u.), significantly surpassing that of BF 4 @C 16 S 8 . These findings demonstrate the promising potential of superhalogen‐doped C 16 S 8 derivatives for future applications in advanced optoelectronic and photonic device technologies.