Novel blue-emitting Eu2+-activated LaOCl:Eu materials

Abstract

A novel blue-emitting LaOCl:Eu²⁺ phosphor has been successfully synthesized using the solid-state reaction. In addition, Ce³⁺ and Tb³⁺ activated LaOCl phosphors have been prepared and compared with the LaOCl:Eu²⁺ phosphor. FE-SEM images clearly indicate that the LaOCl:Eu²⁺ phosphor has a lamellar structure. XRD results and PL measurements for the LaOCl:Eu²⁺ phosphor indicate a preferred orientation along the [001] direction, which results in the blue-emission associated with the spectral characteristics of Eu²⁺. In contrast, the red-emission due to the formation of Eu³⁺ appears in a non-oriented one. These results reveal that Eu²⁺ ions are exclusively stabilized into the (00l) oriented LaOCl crystal lattice because the excitation and emission spectra of the blue-emitting LaOCl:Eu²⁺ phosphor consist of the spectral characteristics of Eu²⁺. The CIE chromaticity index (x = 0.151, y = 0.048) with high color saturation indicates that it is a promising candidate as a blue-emitting phosphor for white-light UV-LEDs.