2D Bismuth Oxyfluorides: A New Member of Cationic Nanosheets

Two kinds of single-crystalline oxyfluoride nanosheets were synthesized by exfoliation of layered bismuth oxyfluorides intercalated with nitrates. The solution-based exfoliation process produced multilayered cationic oxyfluoride nanosheets with thicknesses of several nanometers. A second harmonic gen-eration measurement clarified that one of the nanosheets had a noncentrosymmetric structure. This is the first example of a cationic nanosheet with nonlinear optical properties.