Luminescence properties and thermal stability of Dy3+/Eu3+co-doped single-component BaZn2(PO4)2 glass-ceramic phosphors

Abstract

Highly thermally stable BaZn2(PO4)2: Dy3+/Eu3+ glass-ceramic (GC) phosphors were synthesized using a high-temperature solid-state reaction and controlled-temperature pre-crystallization method. It is found that Dy3+-doped BaZn2(PO4)2 GC phosphors produce cold white light emission at 484 nm and 575 nm under 350 nm excitation with the optimal Dy3+ doping concentration of 0.25 mol%. The theoretical analysis indicates that the dipole-dipole interaction might be the origin of the concentration quenching mechanism of phosphor. The Eu3+-doped BaZn2(PO4)2 GC phosphors produce orange-red emission at 592, 616, 654 and 700 nm under 395 nm excitation. More than that, tunable white light emission can be achieved by optimize the co-doped concentration of Eu3+ on BaZn2(PO4)2: 0.25Dy3+ GC phosphor. The emission spectral intensity and luminescence decay curves from BaZn2(PO4)2: 0.25Dy3+/yEu3+ (range of y) GC phosphors show the energy transfer from Dy3+ to Eu3+ and the emission color can be tuned from cool white to warm white region with the color correlated temperatures (CCTs) reduction from 7299 K to 2520 K. The typical BaZn2(PO4)2: 0.25Dy3+/1Eu3+ GC phosphors have a high thermal stability with an activation energy of 0.30641 eV. Finally, the white LED devices were fabricated by coupling a 363 nm UV light-emitting diode chip with the BaZn2(PO4)2: 0.25Dy3+/yEu3+ GC phosphors. These results suggest that BaZn2(PO4)2: Dy3+/Eu3+ GC phosphors may be suitable candidates for single-component white light-emitting phosphors for application in UV-WLEDs.