Superalkali (Li2F, Li3F) doped Al12N12 electrides with enhanced static, dynamic nonlinear optical responses and refractive indices

Abstract

In the present work, superalkalis (Li2F and Li3F) doped Al12N12 nanocages have been designed and investigated theoretically to elucidate the correlations between geometric, electronic and nonlinear optical properties. All complexes (A-E) are stable inorganic electrides as indicated by their interaction energies (−52.97 to −87.58 kcal/mol). The decrease in HOMO-LUMO energy gaps (5.44–5.87 eV) has caused a remarkable increase in the nonlinear optical response of A-E complexes. The maximum values of first hyperpolarizability (1.20 × 104 a.u.) and second hyperpolarizability (1.65 × 107 a.u.) have been achieved for complex A. The highest dynamic hyperpolarizability coefficients including second harmonic generation (9.08 × 105 a.u.) and electro-optic Pockel's effect (9.56 × 105 a.u.) are obtained for complex A at 532 nm. The electric field-induced second harmonic generation (up to 3.52 × 108 a.u.) and dc-Kerr effect (up to 8.13 ×108 a.u.) along with a large quadratic nonlinear refractive index (up to 5.41 × 10−11 a.u.) of the designed electrides reflected their large NLO response.