The luminescence enhancement of NaLaSiO4:Tb3+ green phosphor by co-substituting Si4+-O2-/La3+-O2- with B3+-F-/Ba2+-F- for white light-emitting diodes

Based on the green emission of NaLa0.82SiO4:0.18Tb3+ phosphor, the luminescence properties including intensity and stability of phosphor was effectively improved via the isomorphic substitution of crystal groups including [B3+-F-]→[Si4+-O2-] and [Ba2+-F-]→[La3+-O2-]. The luminescence intensities (λem = 544 nm) of NaLa0.82Si0.96B0.04O3.96F0.04:0.18Tb3+ and NaLa0.78Ba0.04SiO3.96F0.04:0.18Tb3+ increased to 4.22 times and 5.49 times that of NaLa0.82SiO4:0.18Tb3+, respectively. Moreover, even at an operating temperature of 423 K, these both phosphors retained 95 % of their initial luminescence intensity, demonstrating excellent thermal stability. Notably, the fabricated w-LEDs devices with the as-prepared green phosphors emitted a bright warm white light, which showing excellent colorimetric parameters of CCT = 4596 K and Ra = 89.2. The color gamut of fitted LCD reaches 75.16 % of the National Television System Committee (NTSC) standard. The results indicate that the NaLa0.82Si0.96B0.04O3.96F0.04:0.18Tb3+ and NaLa0.78Ba0.04SiO3.96F0.04:0.18Tb3+ green-emitting phosphors have great potential in the applications of LCD backlight and solid-state lighting.