Enhanced red emission from BaMoO₄ : Eu³⁺ by Bi³⁺ co-doping

Area of Science:

• Materials Science
• Solid State Chemistry
• Luminescence

Background:

• Barium Molybdate (BaMoO₄) is a promising host material for phosphors.
• Doping with rare-earth ions like Europium (Eu³⁺) can induce luminescence.
• Bismuth (Bi³⁺) can act as a sensitizer in phosphors.

Purpose of the Study:

• To synthesize and characterize Bi³⁺, Eu³⁺-doped BaMoO₄ phosphors.
• To investigate the effect of Bi³⁺ co-doping on the optical properties of Eu³⁺ in BaMoO₄.
• To determine the optimal Bi³⁺ concentration for enhanced luminescence.

Main Methods:

• Hydrothermal synthesis method.
• X-ray Diffraction (XRD) for crystal structure analysis.
• Scanning Electron Microscopy (SEM) for morphology.
• Photoluminescence (PL) and Energy Dispersive Spectroscopy (EDS) for optical properties and elemental composition.

Main Results:

• Three distinct particle morphologies were observed.
• Bi³⁺ solubility was low in spherical/rugby-like particles, accumulating in irregular ones.
• Eu³⁺ emissions (⁵D₀ → ⁷F_J) were observed under UV excitation, with ⁵D₀ → ⁷F₂ being most intense.
• Energy transfer from MoO₄^2- and Bi³⁺ to Eu³⁺ was confirmed.
• Red emission intensity of Eu³⁺ doubled with Bi³⁺ co-doping.
• Optimal Bi³⁺ content was found to be 0.4 mol%.

Conclusions:

• Hydrothermal synthesis is effective for producing Bi³⁺, Eu³⁺-doped BaMoO₄ phosphors.
• Bi³⁺ acts as an efficient sensitizer, enhancing Eu³⁺ red luminescence in BaMoO₄.
• The optimal Bi³⁺ concentration of 0.4 mol% yields significantly improved red emission.