Demonstrating the Potential of Alkali Metal-Doped Cyclic COLi Organometallics as Electrides and High-Performance NLO Materials.

In this report, the geometric and electronic properties and static and dynamic hyperpolarizabilities of alkali metal-doped COLi organometallics are analyzed via density functional theory methods. The thermal stability of the considered complexes is examined through interaction energy ( ) calculations. Doping of alkali metal derives diffuse excess electrons, which generate the electride characteristics in the respective systems (electrons@complexant, e@M@COLi M = Li, Na, and K). The electronic density shifting is also supported by natural bond orbital charge analysis. These electrides are further investigated for their nonlinear optical (NLO) responses through static and dynamic hyperpolarizability analyses. The potassium-doped COLi (K@COLi) complex has high values of second- (β = 2.9 × 10 au) and third-order NLO responses (γ = 1.6 × 10 au) along with a high refractive index at 1064 nm, indicating that the NLO response of the corresponding complex increases at a higher wavelength. UV-vis absorption analysis is used to confirm the electronic excitations, which occur from the metal toward COLi. We assume that these newly designed organometallic electrides can be used in optical and optoelectronic fields for achieving better second-harmonic-generation-based NLO materials.