Upconversion luminescence nanomaterials: A versatile platform for imaging, sensing, and therapy

Upconversion luminescence is an optical process that emits high-energy photons by absorbing two or more low-energy photons, which is caused by anti-Stokes luminescence, has attracted significant attention in recent years. Upconversion nanomaterials are superior to quantum dots and organic dyes because of their unique properties, including non-photobleaching, non-blinking, low-toxicity, photostability, high conversion efficiency, high light penetration in biological tissues and long lifetime, from nanoseconds up to 6 orders of magnitude to milliseconds, which render them an ideal kind of fluorescent labels for a variety of analytical formats as well as bioimaging in cancer therapy, showing great potential for both in vitro and vivo imaging and biodetection assays applications. This paper will introduce upconversion luminescence nanomaterials from mechanisms composition and synthesis, moreover, we will also discuss recent progress regarding the applications of upconversion nanomaterials in sensing, imaging and therapy.