Recent progress of rare earth doped upconversion nanoparticles

Due to their unique optical properties, rare earth doped Upconversion Nanoparticles (UCNPs) are experiencing fast momentum nowadays. They have excellent physical and chemical characteristics, including great penetration depth and high chemical stability, etc. which make them widely used in many different fields. In this review, the development and process of upconversion luminescence were described briefly. The latest literature was listed to explicate the special properties in these kinds of materials and their applications for temperature sensing, bioimaging, drug delivery, latent fingerprinting detection, and anti-counterfeiting. Finally, the limitations and prospects of UCNPs are introduced, providing a more comprehensive view of rare earth doped UCNPs and draw more attention.