Schematic representation of the mechanism of PL excitation, energy transfer, and PL emission in Mn²⁺-doped material. The orange lines represent the energy level diagram of the Mn²⁺ ion in a free-ion state (right) and tetrahedrally coordinated environment (left) in a supertetrahedral nanocluster. The dotted arrows indicate nonradiative transitions. PL, photoluminescence. Reprinted with permission from Lin et al. (J Am Chem Soc 2014;136:4769-4779) [24]. Copyright 2014 American Chemical Society.

Progress in Medical Physics 2022;33:11~24 https://doi.org/10.14316/pmp.2022.33.2.11