Understanding of charge transport and non-linear optical responses into π-extended Carbo[n]Helicenes for organic optoelectronic applications

The aims of this study is to investigate the charge transport and Non-Linear Optical (NLO) responses of Chen and Shen (2017), Xiao et al. (2021), Hoffmann (2014), Liégeois and Champagne (2012), Zou et al. (2021) and Wang et al. (2019) [7,9,11,13,15,17]Helicenes. The computational framework DFT/B3LYP/6-311G (d,p) methodology ties the highlights to the computational framework in analyzing the optoelectronic properties and NLO parameters of the Helicenes series. The TD-DFT calculations with same level are utilized to mimic the absorption properties from ground to excited state. The numerical ranges for absorption maxima (370–465 nm) and energy gaps (${\Delta E}_{gap}$) are clearly stated, offering precise insight into the benzene rings chiroptical succession. Ionization potential (I.P.), electron affinity (E.A.), reorganization energies (λ), frontier molecular orbitals (FMOs) and Nucleus Independent Chemical Shift (NICS) are evaluated for the reported Helicenes. The calculated λ_h and λ_e decreases with increasing helicene size and ranges from 236 to 101 meV and 247-213 meV, respectively. The static and dynamic first and second hyperpolarizabilities connects the charge transport properties (λ_h < λ_e) to the potential NLO optical responses. Hyperpolarizabilities in the order of 10⁻²⁴ to 10⁻³¹ esu, suggest these Carbo [n]Helicenes as promising candidates for advanced NLO materials.