| dc.description | Luminescent BaMO4:xmol%Eu3+ materials (M: Mo or W, and x: 0, 2, 4, 6, 8, and 10 mol%) were successfully obtained by a coprecipitation method at room temperature without additional thermal treatment, leading to highly crystalline materials with reduced reaction times and low manufacturing cost. Structural analyses by powder X-ray diffraction and vibrational Raman techniques of the [WO4]2- and [MoO4]2- groups confirm a characteristic scheelite-type structure. The results indicate an average crystallite size at around 30 nm, and a highly pure phase has been supported by Rietveld refinement. SEM-EDS data of BaMO4:xmol%Eu3+ materials identified polycrystalline particles with bipyramidal-like morphology and homogeneous europium ion distribution. Additionally, the band gap energy (Eg) of barium molybdate and tungstate materials were calculated from reflectance data by the single-constant Kubelka-Munk function. Furthermore, the emission intensity, lifetime, and intrinsic emission quantum yield (Q Eu3+/Eu3+) of the materials have been determined and discussed. The luminescent properties of these materials are significantly influenced by the LMCT excitation bands (O2- ??? Mo6+, W6+, and Eu3+) as well as their intense red emission bands assigned to Eu3+ transitions. The experimental intensity parameter values ??2 and ??4 were evaluated from the emission spectra, using the magnetic dipole 5D0 ??? 7F1 transition as the standard reference. It was observed that the ??2 values are much higher than the ??4 values. This result is related to the fact that the 5D0 ??? 7F2 transition presents a much higher intensity than 5D0 ??? 7F1 one suggesting a low local symmetry around the Eu3+ ion, which might be due to angular distortions in the local coordination geometry. The high Q Eu3+/Eu3+ values (60???79%) indicated an overall high emission intensity for the prepared phosphors. These are special photonic features of the Eu3+-doped molybdate and tungstate, suggesting they could be suitable for luminescent materials applications. | |
