Complex Potassium Yttrium Molybdate Phosphates K2Y1 - xEux(MoO4)(PO4)0.9(VO4)0.1: Synthesis and Study of Luminescent Properties

Samples with various dopant contents were obtained using solid-state and sol-gel methods. The resulting single-phase samples have the formula K2Y1-xEux(MoO4)(PO4)(0.9)(VO4)(0.1) (x = 0, 0.005, 0.01, 0.02, 0.03) and are isostructural with K2Y(MoO4)(PO4). The possibility of formation of complex molybdate vanadates (M2MIII)-M-I(MoO4)(VO4) was studied. Unlike their precursor K2Y(MoO4)(PO4), the complex potassium yttrium molybdate phosphates obtained are deliquescent. Their structures contain no water molecules. The absorption and emission spectra of the compounds under study were recorded. In all the spectra, the electric dipole transition D-5(0)-F-7(2) (616 nm) is appreciably more intense than the magnetic dipole transition D-5(0)-F-7(1) (590 nm). This suggests that the coordination environment of the Eu3+ ion keeps asymmetric. The excited-state lifetimes of anhydrous and humidified samples were determined. The average lifetime is the same for all samples (approximate to 1.5 ms), which is due to the stability of their structures.