Deciphering the impact of superalkali metals [M3O (M = Li, Na, K)] doping on sulflower for enhanced NLO responses with efficient energetic offsets: A density functional theory perspective

[Display omitted] •Impact of superalkali metals [M3O(M = Li, Na, K)] doping on sulflower for NLO response is computed employing DFT.•Binding energies from −6.07 to −29.27 kcalmol-1 demonstrate the thermal stability of M3O@sf isomers.•Superalkali metals doping results in an increase in first hyperpolarizability (βo).•Among all the studied isomers, K3O@sf-III exhibited the highest βo value of 3.2 × 107 au.•Investigated M3O@sf isomers are recommended for future NLO applications. With the motive to enhance nonlinear optical (NLO) materials, the geometries, stabilities, and NLO responses of superalkali metals [M3O (M = Li, Na, K)] doped sulflower (Octathio[8]circulene) is explored using DFT simulations and computational characterization. Binding energies from −6.07 to −29.27 kcalmol-1 demonstrate the thermal stability of M3O@sf isomers. The E(H-L) gap was reduced to 84.84 % upon M3O@sf doping. Superalkali metal doping of sulflower substantially improves the first hyperpolarizability (βo) value of complexes. A comparative study illustrates that the hyperpolarizability of the superalkalis has a monotonic relationship with the nature of metal atoms. Among all the studied isomers, K3O@sf-III has the highest βo value of 3.2×107 au. The significant charge transfer (determined by NBO), decrease in excitation energy values, increase in dipole and polarizability values justify that there has been a significant increase in the βo values. This work introduces an opportunity to develop thermally stable NLO materials which can potentially be used for high-performance NLO applications.