Theoretical exploration on switchable NLO response induced by redox properties of polyoxometalates [XNbW11O40]n−/(n+1)- (X = Al, Si, P, S, Ga, Ge, As, Se)

Abstract Calculations based on density functional theory (DFT) have been performed to investigate the relationship between redox properties and second-order nonlinear optical (NLO) responses of Keggin-type anions [XNbW 11 O 40 ] n− (X = Al, Si, P, S, Ga, Ge, As, Se) and their corresponding heteropoly blues. The frontier molecular orbitals, NLO responses and electronic transition properties of fully oxidized anions and heteropoly blues were discussed. It is noticeable that the second-order NLO behaviors can be switched by reduced electrons for these Keggin-type anions. The calculated β 0 value of heteropoly blues [XNbW 11 O 40 ] (n+1)- (X = P, As, S) are 21–23 times as large as those of fully oxidized anions [XNbW 11 O 40 ] n− (X = P, As, S) according to CAM-B3LYP/6-31G* (LANL2DZ basis sets for metal atom) calculations in CH 3 CN. The aim of this work is to combine the attractive redox properties and NLO response of polyoxometalates to obtain the switchable NLO materials.