Sol-gel synthesis and fluorescence features of SrAl4O7:Sm3+ phosphors

Abstract

In this work, we report a series of SrAl4O7:xSm (0.01 ≤ x ≤ 0.11) phosphors synthesized by using a sol–gel technique. The phosphors were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), diffuse reflection spectroscopy (DRS), and photoluminescence (PL) (emission and excitation) spectra. The crystalline nature was analyzed through XRD, and the distribution of the crystalline grains was evaluated by SEM. Both direct (5.75 eV) and indirect (3.58 eV) energy bandgap (Eg) values were extracted through DRS of SrAl4O7:0.03Sm phosphor using the Kubelka–Munk (KM) function. Under 403 nm excitation, SrAl4O7:xSm phosphors exhibit prominent emission at 594 nm (orange) for the 4G5/2→6H7/2 transition. The CIE 1931 chromaticity coordinates of SrAl4O7:0.03Sm phosphor (x = 0.55, y = 0.44) indicate its application in the orange-light emitting display devices.