Theoretical Design of Alkali and Alkaline Earth Metals Doped Cubanes (C8H8) as Novel Nonlinear Optical Materials

Abstract

Novel organic materials have spark the attention of many scientists to design the high performance NLO materials. In the current study, the effect of alkali and alkaline earth metals doped cubanes have been studied by using density functional theory. The strong influence of doped metal atoms on structural, electronic and nonlinear optical prosperities have been investigated. The results have revealed thermodynamic stability of the doped complexes. The HOMO-LUMO energy gap is reduced upto 4.43 eV. Density of state analysis confirmed the formation of new highest occupied molecular orbital that contributes in the reduction of energy gap. The NBO analysis is performed to evaluate the charge transfer between metal atoms and the cubane ring. The NCI and QTAIM studies also validated the nature of the intramolecular interaction. Doping of metal atoms significantly boosts the hyperpolarizability of the complexes. The first hyperpolarizability (βₒ) of 3.01×104 au is observed for K@Cubane. Moreover, second hyperpolarizability (γtot), second harmonic generation (SHG), electro-optic Pockel’s effect (EOPE), electric field-induced second harmonic generation (EFISHG), electro optic Kerr effect (EOKE), hyper-Rayleigh scattering coefficient (βHRS) and nonlinear refractive indices (n2) are also calculated for the designed complexes. The highest dc Kerr of 2.03 × 1011 au and EFISHG of 2.06 × 1012 au are observed at ω= 0.0856 au along with large refractive index (1.15 × 10-5 au ). These remarkable findings offer new perspectives for designing new materials for their future applications in optoelectronics.