KCaLa(PO4)2: Ce3+, Dy3+Phosphorsfor White Light-Emitting Diodes with Abnormal Thermal Quenching and High Quantum Efficiency

The luminous efficiency of the phosphors usually decreases as the operating temperature increases. Thermal stability is a crucial parameter for phosphors. The Ce3+/Dy3+ co-doped KCaLa(PO4)(2) phosphors exhibited excellent thermal stability attributing to abnormal thermal quenching behavior. The energy exchange between trap charges and the level of Dy3+ ions may lead to this behavior. The structure of the phosphors was analyzed and studied. Under the excitation at 324 nm, the luminescence properties and energy transfer behavior were investigated in detail for Ce3+/Dy3+ co-doped KCaLa(PO4)(2) phosphors. The energy transfer efficiency from Ce3+ to Dy3+ reached to 85.5% with dipole-quadrupole mode. The color coordinate points of the phosphor gradually move closer to (0.333, 0.333) as the operating temperature increased. Under the excitation at 324 nm, the internal quantum efficiency of the KCaLa0.88(PO4)(2): 0.10Ce(3+), 0.02Dy(3+) phosphor was found to be 41.7%. Excellent thermal stability and high quantum efficiency would make the Ce3+/Dy3+ co-activated KCaLa(PO4)(2) phosphor a promising application for white LEDs.

Automated summary

The Ce3+/Dy3+ co-doped KCaLa(PO4)(2) phosphors exhibit excellent thermal stability and high energy transfer efficiency, making them a promising candidate for white LED applications.