Control of Particle Morphology and Orientation in Rare-Earth Layered Molybdate Phosphors Particles

Lanthanide molybdate phosphors, AEu(MoO4)2 (AEM; A = Na, K, Rb, and Cs) were successfully synthesized via the hydrothermal method, and their particle morphology was controlled. It was found that the particle morphology of AEM (A = K, Rb, and Cs) changes depending on the amount of AOH added. Due to structural similarity, different particle morphology changes were observed between (1) K and Rb, and (2) Cs. Based on these orientation analyses, it was found that the [Eu(MoO4)2] layer exhibits particularly high light absorption efficiency when it is horizontally aligned with respect to the direction of the excitation light irradiation. This suggests that fluorescence efficiency depends not only on the shape and size of the particles but also on their orientation state.