Influence of the Eu^sup 3+^ dosage concentration on luminescence properties of YPO^sub 4^:Eu^sup 3+^ microspheres

Issue Title: Special Issue: Failure Analysis in Electronic Devices and Materials In this study, YPO^sub 4^:Eu^sup 3+^ microspheres with different Eu^sup 3+^ dosage concentration were fabricated by a facile hydrothermal route at 200 °C for 10 h in the presence of citric acid. The YPO^sub 4^:Eu^sup 3+^ samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and luminescence spectroscopy. The XRD results reveal that the YPO^sub 4^:Eu^sup 3+^ samples presented a tetragonal structure. The TEM and SEM observations demonstrate that the YPO^sub 4^:Eu^sup 3+^ samples with uniform sphere-like morphologies can be obtained at 200 °C for 10 h. The sizes of samples are in the range of 2-2.2 [mu]m. The room temperature luminescence properties of YPO^sub 4^:Eu^sup 3+^ samples were studied using an excitation wavelength of 227 nm. The emission spectrum displays the bands associated to the ^sup 5^D^sub 0^ [arrow right] ^sup 7^F^sub J^ (J = 1, 2 and 4) electronic transitions characteristics of the Eu^sup 3+^ cations at different positions. The influence of Eu^sup 3+^ dosage concentration on luminescence properties of YPO^sub 4^:Eu^sup 3+^ microspheres were studied carefully.[PUBLICATION ABSTRACT]