Approaches to the Multicolor Tuning of Lanthanide-Ion Doped Upconversion Nanoparticles

In recent years, lanthanide-ion doped nanocrystals have attracted considerable attention for its promising applications in multiplexed biological labeling. These materials can convert near-infrared (NIR) light into visible and offer low autofluorescence, high resistance to photobleaching, high penetration depth and large anti-Stokes shifts. With the development of these techniques, the ability to manipulate multicolor output has become more important for its biological and photovoltaic applications. This review mainly focuses on the recent development of various approaches for the multicolor tuning of lanthanide-ion doped upconversion nanoparticles.