Solution combustion synthesis, photoluminescence and X-ray luminescence of Eu3+-doped LaAlO3 nanophosphors

Novel red light emitting LaAlO3:Eu3+ nanophosphors were successfully synthesized by a urea assisted solution combustion synthesis using lanthanum nitrate and aluminum nitrate as oxidizer. The microstructure and morphology of the phosphors were characterized by X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (SEM). The XRD results show that the LaAlO3:Eu3+ samples exhibit a pure R3¯c (No. 167) structure. The optical properties of LaAlO3:Eu3+ nanophosphors were investigated by photoluminescence and X-ray excited luminescence spectroscopy. It is shown that the nanophosphors can be excited by 324 nm (ultraviolet light, the charge transfer band of O2+–Eu3+), 394 nm (the Eu3+7F0→5L6 transition), 466 nm (the Eu3+7F0→5D2 transition) and X-ray radiation, respectively. Under the ultraviolet radiation at 324 nm, the LaAlO3:Eu3+ nanophosphors emit very strong red luminescence, which is suitable for the demands of high-efficiency ultraviolet LEDs. Furthermore, the X-ray excited luminescence of LaAlO3:Eu3+ also shows very efficient red light emission, manifesting that the material is a promising scintillator for radiation detection. Finally, the quenching concentrations for Eu3+ emissions are 9.0 mol%, 12.0 mol% and 6.0 mol% under the excitation of 324 nm, 394/464 nm and X-ray radiation, respectively.