Lu3(Al,Si)5(O,N)12:Ce3+ phosphors with broad emission band and high thermal stability for white LEDs

A yellow-orange emitting Lu3Al5−xSixO12−xNx:Ce3+ phosphor with excellent color rendering, high luminescent efficiency and high thermal stability was reported in this paper. It was synthesized by a conventional solid-state reaction method. The effect of Si4+-N3− incorporation on the optical properties of Lu3Al5O12:Ce3+ phosphor was investigated and compared to YAG:Ce3+ with the same compositions. Similarly, the addition of α-Si3N4 leads to a distinct redshift and broadening of photoluminescent spectrum, which is assigned to the increased covalency and crystal field strength caused by N3−. Nevertheless, an excellent thermal stability and a higher integrated intensity presented by α-Si3N4-doped LuAG:Ce3+ are distinctive. Further, the emission intensity can be greatly enhanced by adding NaF flux. Finally, the white LED flat lamp with a CRI as high as 83 and a luminous efficiency of 85 lm/W is successfully realized by using a single LuAG-based oxynitride phosphor combined with a blue LED chip, which is completely feasible for general indoor illuminations to replace the traditional fluorescent or incandescent lamps.