Amplifying the nonlinear optical response of sunflower-like C16S8 through superhalogen doping

Abstract

Superhalogens, known for their higher electron affinity compared to halogens, exhibit a unique ability to accept electrons from any electron donor specie. Leveraging this property, the doping of superhalogens onto electron-rich surfaces has emerged as a potent approach to augment nonlinear optical (NLO) response. Herein, we investigated the doping of beryllium trifluoride (BeF3), calcium trifluoride (CaF3) and magnesium trifluoride (MgF3) superhalogens on thia[8]circulene (C16S8) sunflower through density functional theory (DFT) calculations, to observe the improvement in the NLO response of resultant complexes. The study explores the thermal stability of complexes through interaction energy analysis, revealing robust structural properties. Conducting properties of the resultant complexes are examined via frontier molecular orbitals (FMOs) analysis, demonstrating notable changes. Molecular electrostatic potential (MEP) and Fukui function analyses gave an idea about the reactivity of the pure C16S8 and superhalogen doped C16S8 complexes. To quantify the NLO response, we assessed the first hyperpolarizability (β o) via comprehensive analysis. Remarkably, the MgF3@C16S8 complex reflects the highest hyperpolarizability value (1.85 × 104 au), signifying its exceptional NLO enhancement potential. Ultra-violet visible (UV–vis) analysis illustrated the increase in the wavelengths (red shift) of C16S8 complexes after doping of superhalogen. To elucidate the underlying factors contributing to the improved NLO response, a rationalization is provided through a two-level model.