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

The integration of trivalent europium ion (Eu)-doped zinc molybdate (ZnMoO) 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 and Eu in ZnMoO, aiming to improve thermal reversibility and reduce the lifetime of electron transitions. A series of Eu-doped ZnMoO and Mn/Eu-co-doped ZnMoO 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 into Eu-doped ZnMoO leads to a decrease in quantum efficiency and electron lifetime, primarily attributed to defects within the crystal lattice and energy transfer from Eu to Mn, resulting in enhanced non-radiative transitions. However, the addition of a small quantity of Mn 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-only doped samples are well-suited for lighting applications due to their high IQE and excellent thermal stability. Conversely, Eu/Mn-co-doped samples show promise in applications that require a shorter electron lifetime and good reversibility.