Effect of Li doping on the luminescence performance of a novel KAlSiO:Tb green-emitting phosphor.

A new green-emitting phosphor, KAlSiO:1.5 mol% Tb, x mol% Li, was prepared via a high-temperature solid-phase method, and its crystal structure, diffuse reflectance spectrum, and luminescence were studied. The results show that the Li doping shifts the strongest diffraction peak to a high angle direction, reducing grain size by 11.4%. The entry of LiCO improves the luminescence performance of KAlSiO:1.5 mol% Tb. At a Li concentration of 1.5 mol%, the sample has strong absorption in the ultraviolet light range from 250 to 400 nm. The luminous intensity of the sample at 550 nm approximately quadruples after Li doping. Additionally, the colour purity of the sample and the internal quantum yield increase to 83.3% and 42%, respectively. The sample changes colour with time when exposed to air without an obvious fading phenomenon. The emission intensity at 200 °C is 95.1% of its value at room temperature, indicating that the phosphor has excellent thermal stability when x = 1.5. These results show the feasibility of using the silicate phosphor for generating the green light component of white light-emitting diodes for solid-state lighting.