High quantum efficiency red emitting α-phase La2W2O9:Eu3+ phosphor

High-quality inorganic red-emitting phosphors are widely used in white light-emitting diodes to realize excellent white light emission. Tungstate is one of the most popular materials for phosphors due to their great chemical stability and unique luminescent properties. However, the quantum efficiency of tungstate-based phosphor is still not high enough for commercial application. In this study, we synthesized a series of alpha-La2W2O9: Eu3+ phosphors by a modified high-temperature solid-state reaction method. The prepared phosphors crystallized well in triclinic structure. Eu3+ ion mainly substituted La3+ ion in La (1) site of low local symmetry as C-1, thus the phosphors showed a strong red emission at 618 nm by D-5(0) -> F-7(2) transition. When Eu3+ doping concentration is 3%, alpha-La2W2O9: 3%Eu3+ presents maximum luminescent intensity, longest lifetime (0.651 ms) and highest quantum yield (77%). Furthermore, the mechanism of concentration quenching is discussed and indicates that electric dipole-dipole interaction is the dominant mechanism. Our study demonstrates a high-quality red-emitting phosphor based on alpha-La2W2O9: 3%Eu3+, which is potential for commercial white light-emitting diodes applications. (C) 2018 Elsevier B.V. All rights reserved.