Energy transfer in lanthanide upconversion studies for extended optical applications

Lanthanide pairs, which can upconvert low energy photons into higher energy photons, are promising for efficient upconversion emission. A typical system with Yb(3+) as a sensitizer can convert short NIR into visible/ultraviolet light via energy transfer between lanthanide ions. Such upconverting nanocrystals doped with lanthanide ions have found significant potential in bioimaging, photochemical reactions and energy conversion. This review presents a fundamental understanding of energy transfer in lanthanide-supported photon upconversion. We introduce the emerging progress in excitation selection based on the energy transfer within lanthanide ions or activation from antennae, with an outlook in the development…