Judd–Ofelt Intensity Parameters and Optical Properties of Eu/Li Co‐Doped CeO₂ Phosphor

Abstract

In this work, the intense orange‐red emission of Eu3+ singly and Eu3+/Li+ co‐doped CeO2 phosphors synthesized by solution combustion using urea as fuel was investigated experimentally and theoretycally. X‐ray diffraction and high‐resolution transmission electron microscope analysis confirmed the formation of a single‐phase CeO2 cubic with high crystallinity. Under 360 nm excitation, the phosphors emitted an intense orange–red region of Eu3+ as a function of Li+ doping content. Significantly, it was enhanced 12/10 times by Li+ co‐doping due to the increased crystallinity of the host lattice. The energy transfer proccesse associated with cross‐relaxation is responsible for decreasing the experimental lifetime of Eu3+. The influence of Li+ doping content on the characterization properties of CeO2:Eu, Li phosphors was further explained using Judd‐Ofelt (J−O) theory, from which branching ratios (βr), transition probability (A), radiative lifetime (τcal), and stimulated cross‐section (σe) emission of the phosphors were estimated. The results indicate that an effectively improved crystallinity by Li+ co‐doped CeO2:Eu can significantly enhance its luminescence intensity, making it suitable for optoelectronic and display applications.