Up-conversion process and mechanism of up-conversion luminescent materials
Its principles include excited state absorption (ESA), energy transfer up conversion (ETU), and photon avalanche (PA). Energy transfer refers to the coupling of two excited ions with similar energy through a non-radiative process, one of which transfers energy to the other and returns to a low energy state, and the other ion receives energy and transitions to a higher energy state. Energy transfer upconversion can occur between the same ions, or between different ions. Therefore, energy transfer up-conversion can...