Superalkalis as a source of diffuse excess electrons in newly designed inorganic electrides with remarkable nonlinear response and deep ultraviolet transparency: A DFT study

Recently, significant progress is observed in the design and synthesis of nonlinear optical materials due to their optoelectronic and biomedical applications. In this report, a series of inorganic electrides (Li2F@Al12P12, Li3O@Al12P12 and Li4N@Al12P12) are designed by doping of Al12P12 nanocluster with superalkalis (Li2F, Li3O and Li4N) and studied through density functional theory (DFT) for their geometrical, electronic and nonlinear optical properties. Computational results indicated that these superalkalis doped complexes possess high stability and low HOMO-LUMO gaps. Interaction energies reveal that adsorption of Li4N on Al-top site of Al12P12 results in highly stable structure (isomer J), where superalkali is strongly chemisorbed on the nanocage (E-int. = -105.13 kcal mol(-1)). Moreover, the lowest HOMO-LUMO gap is also observed for J isomer of Li4N@Al12P12 (0.44 eV), compared to 0.94 eV for alkali metal doped Al12P12 nanocage and 3.36 eV for pure nanocage. Doping of superalkali on aluminum phosphide nanocage can bring considerable increase in first hyperpolarizabilities (beta(o)) response of the nanocage along with deep ultraviolet transparency. The first hyperpolarizability (beta(o)) for isomer J of Li4N@Al12P12 is 6.25 x 10(4) au. This study may provide an effective strategy to design high performance NLO materials from stable inorganic electrides.