Rb VO(O ) CO : A Four-in-One Carbonatoperoxovanadate Exhibiting an Extremely Strong Second-Harmonic Generation Response.

A nonlinear optical (NLO) carbonatoperoxovanadate, Rb VO(O ) CO , was synthesized through a simple solution-evaporation method in phase-pure form. Single-crystal X-ray diffraction revealed that the structure of Rb VO(O ) CO consists of important noncentrosymmetric (NCS) chromophores, that is, π-delocalized (CO ) groups, a second-order Jahn-Teller (SOJT) distortive V cation, and π-localized distorted O groups, as well as charge-balancing polarizable Rb ions. The powder second-harmonic generation (SHG) measurements indicated that Rb VO(O ) CO is phase-matchable (Type I) and exhibits a remarkably strong SHG response circa 21.0 times that of potassium dihydrogen phosphate (KDP), which is the largest efficiency observed among carbonate NLO materials. First-principles calculation analysis suggests that the extremely large SHG response of Rb VO(O ) CO is attributed to the synergistic effect of the cooperation of all the constituting NCS chromophores.