The Bond-Energy Method in Site Occupancy and Property of High Concentration Eu3+ in Sr₂CeO₄ Phosphors

J Nanosci Nanotechnol. 2019 Feb 1;19(2):1145-1147. doi: 10.1166/jnn.2019.15921.

Abstract

The low concentration of Eu3+ doped Sr₂CeO₄ phosphors has been widely studied in recent years and in this paper, we researched the properties of high concentration Eu3+ doped in Sr₂CeO₄. The Sr₂Ce(1-x)Eu4-x/2 (x = 0, 1%, 10%, 20%) phosphors were obtained by traditional solid-state reaction. Photoluminescence (PL) spectra are characterized the property of samples. PL spectra illustrate that the concentration of Eu3+ increased, the intensity of 5D0-7F1, 5D0-7F₂ increased and intensity of Sr₂CeO₄ host emission intensity was decreased. The phenomenon can be ascribed to the energy transfer from Ce4+ to Eu3+. When the concentration of Eu3+ is 20%, the completely red emission can be obtained even if no other ions are doped under the excitation wavelength of 350 nm, it is proved that Eu3+ occupied Ce sites rather than Sr site in Sr₂CeO₄ samples. The conclusion we make is due to the value of |ΔEEuCe-O| and |ΔEEuSr-O| calculated by bond-energy method, the smaller the value, the easier it is for the doped ions Eu3+ to enter the site.