Intense Orange Red Emission from Sm3+-Activated Ca3Al2O6 Phosphor for Display Device Application

Abstract

The synthesis and the structural and luminescence studies of samarium-doped calcium aluminate phosphors are reported. These phosphors are synthesized by the solid-state reaction method with a variable concentration of doping ions (0.5–3.0 mol%). The synthesized phosphors are characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) techniques. The XRD studies show that the doped phosphors have a cubic structure. The SEM images reveal that the Sm³⁺- doped Ca₃Al₂O₆ phosphor represents a combination of some rod-like and flower-like structures. The FTIR studies confirm the formation of a Ca₃Al₂O₆:Sm³⁺ phosphor. The photoluminescence (PL) emission measurements upon excitation by 273 nm (ultraviolet light) show the characteristic emission peaks of Sm³⁺ at 579, 589, 600 and 619 nm. The characteristic orange-red emission is observed for samarium ion. The excitation spectra of the Ca₃Al₂O₆:Sm³⁺ phosphor mainly consist of a more intense charge transfer band (CTB) of Sm³⁺ located at 273 and 395 nm with some peaks centred at 319 and 362 nm. The CIE coordinates are calculated by the spectrophotometric method using the spectral energy distribution of the Ca₃Al₂O₆:Sm³⁺ sample. The prepared phosphors can act as a single host for orange-red light emission in display devices.