Effects of the atomic number of alkali atom and pore size of graphyne on the second‐order nonlinear optical response of superalkali salts of graphynes OM3+@GYs− (M = Li, Na, and K).

Based on the combination of novel carbon material graphynes (GYs) and superalkalis (OM3), a class of GY superalkali complexes, OM3+@(GY/GDY/GTY)− (M = Li, Na, and K), has been designed and investigated using the density functional theory method. Computational results reveal that these complexes with high stability can be regarded as novel superalkali salts of GYs due to electron transfer from OM3 to GYs. For second‐order nonlinear optical response, these superalkali salts exhibit large first hyperpolarizabilities (β0). Two essential effects on β0 values are found, namely, the atomic number of alkali atom in superalkali and the pore size of GY. Integrating the two effects, the selected combination of OLi3 with large pore size graphtrigne (GTY) can lead to a considerable β0 value (6.5 × 105 au), which is a new record for superatom‐doped GYs. In the resulting complex, the OLi3 unit is located at the center of the pore of GTY, forming a planar structure with the highest stability among these salts. Besides large β0 values, these superalkali salts of GYs have a deep‐ultraviolet working region; hence, they can be considered a kind of high‐performance deep‐ultraviolet NLO molecule. [ABSTRACT FROM AUTHOR]