Fig. 2. Characterization of UCNPs and CS-UCNPs. (a and b) TEM images of the core-UCNPs (a) and CS-UCNPs (b). (c) Photographs of core-UCNPs (left) and CS-UCNPs (right) in the cyclohexane solution under the same 980 nm laser excitation. (d) Luminescence properties of core-UCNPs (red line) and CS-UCNPs (black line). (e) High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image and its corresponding elemental contents of CS-UCNPs.
