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

Abstract

A series of Ce³⁺/Tb³⁺ 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 Ce³⁺ and Tb³⁺ ions was calculated by both the concentration quenching method and the spectral overlap method. The energy transfer mechanism from the Ce³⁺ to Tb³⁺ 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 Ce³⁺/Tb³⁺ contents, the emission color of the obtained phosphors can be tuned from blue to green light. The MgZn₂(PO₄)₂:Ce³⁺,Tb³⁺ 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.