Fig. 5From: Mechanism of Fluorescence Enhancement of Biosynthesized XFe2O4–BiFeO3 (X = Cr, Mn, Co, or Ni) Membranes a Surface potential images and b the relative potential curves of XFO–BFO membranes by AFM–KPFM measurement. Therein, the scanning area is 5 μm × 5 μm. The particles are essentially in agreement with the differences of grain sizes in SEM imagesBack to article page