Photoluminescence Property and Concentration Quenching of Orange-Red–Emitting Samarium Activated BaAl2O4 Phosphor for White LEDs

Abstract

A series of Sm³⁺ activated BaAl₂O₄ phosphors was effectively synthesized by a known combustion method. Structural and optical properties are investigated by using X-ray diffraction pattern (XRD), Fourier transform infrared (FTIR), and photoluminescence (PL) analysis. The XRD of the prepared sample exhibits that all the samples prepared are in a single phase and match with standard JCPDS no. 01–072-1331. The XRD pattern indicates a hexagonal structure. The FTIR spectra of the BaAl₂O₄ sample show the stretching vibrations of aluminum-oxygen, barium-oxygen, and barium-oxygen-aluminum bonds, confirming the presence of the BaAl₂O₄ structure. The luminescence properties are broadly investigated by recording their PL excitation and emission spectra. The BaAl₂O₄:Sm³⁺ phosphors show a strong absorption range in 340–420 nm, which is well suited for application in LEDs. Under the excitation wavelength of 403 nm, the BaAl₂O₄:Sm³⁺ phosphor emits yellow, orange, and red emissions along the Commission Internationale de l'Éclairage (CIE) chromaticity coordinates found at 565 nm (0.408, 0.589), 603 nm (0.640, 0.359), and 650 nm (0.725, 0.274) (0.615). The optimal doping concentration of Sm³⁺ doped BaAl₂O₄ is at 1 mol %. The concentration mechanism is studied, and this mechanism arises from the dipole–dipole interaction between Sm³⁺ ions. The results demonstrate that BaAl₂O₄:Sm³⁺ phosphors have the potential to function as red–orange phosphors for white LEDs.