Synthesis and photoluminescence properties of Er3+ and Dy3+ doped Na2NbAlO5 phosphors

A series of Ln3+ (Ln3+ = Er3+/Dy3+) ions doped Na2NbAlO5 (NNAO) phosphors were synthesized by solid-state method. The Er3+ and Dy3+ ions doped phosphors were characterized by XRD, photoluminescence (PL) and decay profiles. The Ln3+-doped samples are consistent with the pure NNAO phase which is analyzed by the X-ray diffraction result. The PL graphs show that the intensity of luminescence increases with the increasing doping concentrations up to their critical certain values and then decreases at higher concentrations due to the concentration quenching effect of Er3+/Dy3+ ions. The energy level diagrams containing the positions of 4f and 5d energy levels of Er3+ and Dy3+ ions have been established and studied. In addition, under the ultraviolet light, the prepared NNAO:xLn3+ (Ln3+ = Er3+/Dy3+) phosphors show the characteristic green (Er3+), cyan (Dy3+) emission, respectively. Under the excitation of 365 nm, the quantum efficiencies of NNAO:0.01Er3+ and NNAO:0.03Dy3+ phosphors are measured to be 61.7% and 72.2%, respectively. The obtained results indicate that the new NNAO:xLn3+ (Ln3+ = Er3+/Dy3+) phosphors are promising applications in white-light emitting diodes field.