Lanthanide-doped upconversion nanomaterials

Lanthanide-doped upconversion nanomaterials that can convert multiple low-energy photons into one high-energy photon have been regarded as a distinctive class of luminescent nanomaterials. Owing to their highly programable morphologies, emission colors and lifetimes, lanthanide-doped upconversion nanomaterials have found broad applications in bioimaging, multiplexing sensing, anticounterfeiting, lasing, and optogenetics. This chapter reviews recent scientific and technological achievements in developing high-efficiency upconversion nanocrystals, emphasizing emerging applications such as super-resolution microscopy, lasing, and optogenetics.