Facially Polarized Molecule for Alkalides and Superalkalides with Considerable Nonlinear Optical Response

In this work, alkali M (Li and K) and superalkali M′₃O (M′=Li and Na) combined with facially polarized molecule, all-cis 1,2,3,4,5,6-Hexafluorocyclohexane (L, C₆H₆F₆), were utilized to design novel alkalides L-M-L-M′ and superalkalides L-M-L-M′₃O, respectively. Computational results show that alkalides L-M-L-M′ and superalkalides L-M-L-M′₃O have high thermodynamic stability, and the superalkalides L-M-L-M′₃O are more stable than the alkalides L-M-L-M′. Importantly, they also possess remarkable NLO responses, the electronic contribution of the static first hyperpolarizability (β₀ ^e) has upped to 3.42×10⁶ (a.u.) for L-K-L-Li₃O. In particularly, the number of ligand L considerably impacts on β₀ ^e value, namely, the β₀ ^e value of Li-L-Li₃O can be improved two orders of magnitude by adding additional ligand L, 1.31×10⁶ (a.u.)(L-Li-L-Li₃O) > 7.76×10⁴ (a.u.)(Li-L-Li₃O). We hope this work can attract researchers to design and synthesize novel excess electron compounds with high performance NLO materials.