Controlling persistent luminescence in nanocrystalline phosphors

Persistent luminescent phosphors can store light energy in advance and release it with a long-lasting afterglow emission. With their ability to eliminate in situ excitation and store energy for long periods of time, they are promising for broad applications, including background-free bioimaging, high-resolution radiography, conformal electronics imaging and multilevel encryption. This Review provides an overview of various strategies for trap manipulation in persistent luminescent nanomaterials. We highlight key examples in the design and preparation of nanomaterials with tunable persistent luminescence, particularly in the near-infrared range. In subsequent sections, we cover the most current developments and trends concerning the use of these nanomaterials in biological applications. Moreover, we assess their advantages and disadvantages compared with conventional luminescent materials for biological applications. We also discuss future research directions and challenges, such as insufficient brightness at the single-particle level, and possible solutions to these challenges.