Nonlinear optical (NLO) materials have garnered considerable attention across various fields due to their versatile applications. In this work, the potential of Li3O, Na3O, and K3O complexed 6cycloparaphenylene (6CPP) and methylene-bridged 6cycloparaphenylene (MB6CPP) nanohoops as promising NLO candidates has been systematically explored using density functional theory. The geometric, electronic, linear, and nonlinear optical properties of these designed complexes have been investigated. All designed nanohoops exhibited excellent thermodynamic stability, with binding energies reaching up to −93.23 kcal/mol. Remarkably, superalkali complexation has significantly reduced the HOMO–LUMO energy gaps (3.21 eV) compared to the pristine systems and primarily due to the formation of HOMO levels, as confirmed by the TDOS and PDOS analyses. The absorption analysis reflects that the superalkali-based CPPs have an absorption maximum in the visible to near-infrared region, 728–1280 nm. Furthermore, the superalkali-complexed nanohoops displayed outstanding NLO responses, with the Li3O@MB6CPP complex showing the highest first hyperpolarizability value of 1.62 × 105 au. Moreover, dynamic first hyperpolarizabilities were also calculated at the four commonly used wavelengths to further validate the results. These findings highlight the potential of superalkali-complexed 6CPP nanohoops as advanced NLO materials with possible applications across various cutting-edge photonic and optoelectronic technologies.
Bano et al. (Mon,) studied this question.