Improvement of the red emitting phosphor by introducing A + (A = Li, Na, K) into Sr 3 La(PO 4 ) 3 :Eu 3+

We proposed and experimentally demonstrated a novel doped scheme to improve the emission intensity of red emitting phosphor Sr3La(PO4)3:Eu3+. By doping a series of A+ (A = Li, Na, K) into Sr3La(PO4)3:Eu3+, the normalized emission intensities of Sr3La(PO4)3:Eu3+ can be distinctly enhanced. For example, when doping 5%A+ into Sr3La(PO4)3:5%Eu3+, the emission intensities of Sr3La(PO4)3:5%Eu3+ are increased by 3.558 (Li+), 1.768 (Na+) and 1.215 (K+) times, respectively. Obviously, for the three candidates (Li+, Na+ and K+), Li+ is the best. The CIE chromaticity coordinates of Sr3La(PO4)3:5%Eu3+, 5%Li+ are (0.6271, 0.3714), which are quite close to that of commercial red phosphors Sr2Si5N8:Eu2+ and Y2O2S:Eu3+, and the quantum efficiency is 33.1%. The result indicates Sr3La(PO4)3:Eu3+, Li+ may be a potential application in white light emitting diodes.