Luminescent Properties of Yellow Phosphors SrAl2O5Cl2: Eu2+, Ln3+ (Ln3+ = Y3+, La3+) and Their Applications on Near UV LED Chips

New yellow phosphors, SrAl2O5Cl2: Eu2+, Ln(3+) (Ln(3+) = Y3+, La3+), were prepared by solid state reaction technique, and their structure and optical properties were investigated. These phosphors show broadened the excitation band in near UV range and intense yellow emission under 400 nm light excitation by introducing into Y3+ and La3+ ions, Sr2.6Al2O5Cl2: 0.20Eu(2+), 0.20 La3+ shows intense yellow emission under near UV light excitation, and its intensity is about 1.56 times higher than that of Sr2.8Al2O5Cl2: 0.20Eu(2+). The single yellow light-emitting diodes were fabricated by combining near UV LED chips with Sr2.6Al2O5Cl2:0.20Eu(2+), 0.20 Y3+ and Sr2.6Al2O5Cl2:0.20Eu(2+), 0.20 La3+, and intense yellow light can be observed by naked eyes from the yellow LEDs, so these phosphors may be applied in fabrication of phosphor-converted near UV light-emitting diodes.