Mengjiao Xu

Luminescence, energy transfer and tunable color of Ce3+,Dy3+/Tb3+ doped BaZn2(PO4)2 phosphors

Ce3+,Dy3+ and Tb3+ doped BaZn2(PO4)2 phosphors were prepared via a high temperature solid state reaction route. The crystal structure, photoluminescence properties, decay lifetime, luminous efficiency and thermal stability of the phosphors were investigated. The mechanism of Ce3+–Dy3+/Tb3+ energy transfer was determined to be a dipole–dipole interaction based on the photoluminescence spectra and decay curves of the phosphors. The critical distance between the Ce3+ and Dy3+/Tb3+ ions was calculated using both the concentration quenching method and the spectral overlap method. Tunable emission from blue to bluish white and green can be realized by energy transfer and changing the doping concentrations of Dy3+ and Tb3+ under UV light. BaZn2(PO4)2:Ce3+,Dy3+/Tb3+ phosphors are proved to be promising candidates in the lighting field due to their excellent thermal stability and luminescence properties.

Photoluminescence properties and energy transfer of color tunable MgZn2(PO4)2:Ce3+,Tb3+ phosphors

A series of Ce(3+)/Tb(3+) co-doped MgZn2(PO4)2 phosphors have been synthesized by the co-precipitation method. Their structure, morphology, photoluminescence properties, decay lifetime, thermal stability and luminous efficiency were investigated. The possible energy transfer mechanism was proposed based on the experimental results and detailed luminescence spectra and decay curves of the phosphors. The critical distance between Ce(3+) and Tb(3+) ions was calculated by both the concentration quenching method and the spectral overlap method. The energy transfer mechanism from the Ce(3+) to Tb(3+) ion was determined to be dipole-quadrupole interaction, and the energy transfer efficiency was 85%. By utilizing the principle of energy transfer and appropriate tuning of Ce(3+)/Tb(3+) contents, the emission color of the obtained phosphors can be tuned from blue to green light. The MgZn2(PO4)2:Ce(3+),Tb(3+) phosphor is proved to be a promising UV-convertible material capable of green light emitting in UV-LEDs due to its excellent thermal stability and luminescence properties.