Reversibly Photoswitchable Tristate Fluorescence within a Single Polymeric Nanoparticle

Abstract Herein, a class of novel photoswitchable tristate fluorescent polymeric nanoparticles (TS‐PFPNs) consisting of a well‐designed perylenediimide‐spiropyran conjugate (PDI‐SP), two energy‐matched photochromics as spiropyran‐linked methacrylate and diarylethene (DTE) derivative (DTEo‐1) is described. By optimizing the feed ratio of three dyes and controllable switching fluorescence resonance energy transfer from excited PDI to SP or DTE moiety with different lights stimuli, the emission of these TS‐PFPNs can be reversibly switched among distinguishable green, red, and quenching states. In addition, these TS‐PFPNs exhibit high brightness, high contrast, excellent water‐dispersibility, and photoreversibility as well as outstanding long‐term storage stability and processability. It is also demonstrated that these TS‐PFPNs can be directly used for advanced anticounterfeiting, high‐density data storage, and multilevel information encryption.