Influence of Mn 2+ and Eu 3+ Concentration on Photoluminescence and Thermal Stability Properties in Eu 3+ -Activated ZnMoO 4 Red Phosphor Materials.

The integration of trivalent europium ion (Eu 3+ )-doped zinc molybdate (ZnMoO 4 ) as red phosphors in next-generation solid-state lighting (SSL) is impeded by their extended electron lifetime and suboptimal thermal stability. To overcome these limitations, we propose a co-doping approach by incorporating Mn 2+ and Eu 3+ in ZnMoO 4 , aiming to improve thermal reversibility and reduce the lifetime of electron transitions. A series of Eu 3+ -doped ZnMoO 4 and Mn 2+ /Eu 3+ -co-doped ZnMoO 4 phosphor materials were synthesized via the conventional sol-gel method, and their photoluminescence properties were compared under high-temperature conditions. Experimental results indicate that the introduction of Mn 2+ into Eu 3+ -doped ZnMoO 4 leads to a decrease in quantum efficiency and electron lifetime, primarily attributed to defects within the crystal lattice and energy transfer from Eu 3+ to Mn 2+ , resulting in enhanced non-radiative transitions. However, the addition of a small quantity of Mn 2+ remarkably improves the thermal stability and reversibility of the phosphors. Consequently, this co-doping strategy presents a promising avenue for expanding the application possibilities of phosphor materials, particularly for high-power SSL applications subjected to elevated temperatures. Hence, Eu 3+ -only doped samples are well-suited for lighting applications due to their high IQE and excellent thermal stability. Conversely, Eu 3+ /Mn 2+ -co-doped samples show promise in applications that require a shorter electron lifetime and good reversibility.