Self-assembled CaMoO_4 and CaMoO_4:Eu~(3+) hierarchical superstructures: Facile sonochemical route synthesis and tunable luminescent properties

摘要

Tetragonal CaMoO_4 and CaMoO_4:Eu~(3+) with various novel three-dimensional (3D) hierarchical archi- tectures were successfully synthesized via a facile, efficient sonochemistry process in the absence of any surfactant or template. XRD, EDS, FE-SEM, and photoluminescence (PL) were employed to characterize the as-obtained products. It was found that morphology modulation could be easily realized by changing pH value of the precursor. The pH value of the precursor not only affected the substructures of the hierarchical structures, but also determined the size distributions of the final products. The formation mechanism for different hierarchical architectures was proposed on the basis of time-dependent experiments. The luminescence spectra showed that CaMoO_4:Eu~(3+) phosphors can be effectively excited by the near ultraviolet (UV) (396 nm) and blue (466 nm) light, and exhibited strong red emission around 615 nm, which was attributed to the Eu~(3+) ~5D_0→~7F_2 transition. Compared with Y_2O_3:Eu~(3+) phosphor, CaMoO_4:Eu~(3+) is much more stable, efficient and suitable, therefore, this phosphors could be a promising red component for possible applications in the field of LEDs.