“…A vast number of organic excess-electron systems with enhanced NLO responses have widely been designed by doping metals in organic molecules, including cyclic pyrroles [ 8 ], polyamines [ 9 ], fluorocarbons [ 6 ], conducting polymers [ [10] , [11] , [12] ], graphene quantum dots [ 13 ], resulting in alkalide [ [14] , [15] , [16] , [17] , [18] , [19] ], alkaline earthide [ [20] , [21] , [22] , [23] ], and electrides [ 5 , 24 , 25 ], with outstanding NLO activity. Alkalides are ionic salt containing alkali metals (such as, Li/Na/K) as anion.…”