Analysis of the Shell Thickness Distribution on NaYF4/NaGdF4 Core/Shell Nanocrystals by EELS and EDS

The structure and chemical composition of the shell distribution on NaYF4/NaCdF4 core/shell nanocrystals have been investigated with scanning transmission electron microscopy (STEM) electron energy loss spectroscopy (FELS) and energy dispersive X-ray spectroscopy (FDS). The core and shell contrast in the high-angle annular dark field (HAADE) images combined with the EELS and EDS signals indicate that Gd is indeed on the surface but for many of the particles, the shell growth was anisotropic.