Local Structure of Europium‐Doped Luminescent Strontium Fluoride Nanoparticles: Comparative X‐ray Absorption Spectroscopy and Diffraction Study

Abstract Rare‐earth based luminescent materials are key functional components for the rational design of light‐conversion smart devices. Stable Eu³⁺‐doped strontium fluoride (SrF₂) nanoparticles were prepared at room temperature in ethylene glycol. Their luminescence depends on the Eu content and changes after heat treatment. The crystallinity of heat‐treated material increases in comparison with as‐synthesized samples. Particles were investigated in solution using X‐ray diffraction, small‐angle X‐ray scattering, and X‐ray spectroscopy. After heat treatment, the size of the disordered nanoparticles increases together with a change of their local structure. Interstitial fluoride ions can be localized near Eu³⁺ ions. Therefore, non‐radiative relaxation from other mechanisms is decreased. Knowledge about the cation distribution is key information for understanding the luminescence properties of any material.