Self-assembled CaMoO4 and CaMoO4:Eu3+ hierarchical superstructures: Facile sonochemical route synthesis and tunable luminescent properties

• For the first time, CaMoO4:Eu3+ phosphors were produced via a simple sonochemical route.
• The morphology of CaMoO4 and CaMoO4:Eu3+ were found to be manipulated by changing the pH value of precursor solution.
• The products have tunable luminescent properties due to their different morphologies.
• The synthesis method influences the final properties of the materials.

Tetragonal CaMoO4 and CaMoO4:Eu3+ with various novel three-dimensional (3D) hierarchical architectures 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 CaMoO4:Eu3+ 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 Eu3+5D0→7F2 transition. Compared with Y2O3:Eu3+ phosphor, CaMoO4:Eu3+ is much more stable, efficient and suitable, therefore, this phosphors could be a promising red component for possible applications in the field of LEDs.

The morphology of the samples were found to be manipulated by changing the pH value of the precursor solution. Uniform CaMoO4 3D dumbbell-like microstructure could be trapped at pH 7 and the flower-like and elliptic cylinder microstructures were obtained at pH 5. When the pH value was adjusted to 9, the doughnut-shaped CaMoO4 structures were obtained. When the pH value was adjusted to 11, the peony-shaped CaMoO4 structures were obtained. The luminescence spectra showed that CaMoO4 doped with Eu3+ phosphors can be effectively excited by the near ultraviolet (UV) and blue light.Figure optionsDownload as PowerPoint slide