Optimizing crystallinity to enhance X-ray excited persistent luminescence intensity of NaLuF4: Gd/Tb nanoparticles

Lanthanide doped fluoride nanoparticles (NPs) exhibit tunable X-ray excited persistent luminescence (XEPL), which show promising applications in optical imaging, cancer therapy and information storage. Although a few progresses have been achieved in enhancing the XEPL of lanthanide activators, there is no report about the influence of crystallinity on the XEPL intensity. In this work, we verify that the XEPL intensity can be improved by optimizing the NP crystallinity. Our results reveal that better crystallinity benefit the lower non-radiative relaxation possibility but also the restriction of the formation of Frenkel defects. This work provides impor-tant information for the development of lanthanide doped fluoride nanoparticles with superior XEPL performances.