Structural, photoluminescence, and photocatalytic performances of Ce3+ -activated orthovanadate oxides M3 (VO4 )2 (M: Mg or Zn) synthesized by solution combustion route.

This paper presents a research investigation into the synthesis of vanadate oxides M3 (VO4 )2 (M: Mg or Zn) using the solution combustion method and investigates their structural, photoluminescence, and photocatalytic properties after introducing cerium (Ce) as a dopant. The resulting synthesized samples all display an orthorhombic crystalline structure with crystallite sizes ranging from 71 to 110 nm. Morphological diversity among the samples is revealed through field-emission scanning electron microscopy (FESEM) imagery. Diffuse reflectance spectroscopy discloses that the introduction of Ce3+ as a dopant leads to an increase in the band gap energy. Notably, when excited at a wavelength of 340 nm, the photoluminescence emission intensity reaches its peak across all samples. This intensity undergoes enhancement due to Ce3+ doping, causing a slight shift toward shorter wavelengths attributable to the augmented band gap resulting from the dopant. Markedly, among the investigated materials, Ce3+ -activated Mg3 (VO4 )2 stands out with the most pronounced emission intensity, positioning it as a highly promising luminescent material. Additionally, the incorporation of Ce3+ has a positive effect on the photocatalytic performance of Mg3 (VO4 )2 , resulting in notable improvement.

Effect of (Ce, Dy) co-doping on the microstructural, optical, and photoluminescence characteristics of solution combustion synthesized ZnO nanoparticles.

Solution combustion synthesized ZnO nanoparticles that were Ce doped, Dy doped or co-doped at varying dopant concentrations were characterized for their microstructural, optical, and photoluminescence (PL) characteristics. The synthesized nanoparticles matched the standard hexagonal wurtzite structure of ZnO. The lattice fringes in the high-resolution transmission electron micrographs and the bright spotty rings in the selected area electron diffraction patterns authenticated the high crystallinity of the nanoparticles. The diffuse reflectance spectroscopy resolved the energy bandgap for the undoped ZnO as 3.18 eV, which decreased upon doping and co-doping. A sharp narrow ultraviolet emission peak at ~398 nm that originated from excitonic recombination was found in the PL spectra of the nanoparticles. The visible emission peaks in the PL spectra were assigned to the f-d and f-f electron transitions of Ce3+ and Dy3+ ions, respectively, in addition to different native defects in ZnO. The visible emissions (blue, yellow, and red) improved upon (Ce, Dy) co-doping, therefore (Ce, Dy) co-doped ZnO nanoparticles can be considered a promising luminescent material for the development of energy-saving light sources.