SYNTHESIS AND STUDY ON THE PROPERTIES OF CaMoO4:Eu3+ CO-DOPEDTb3+ MATERIALS TO ENHANCED RED PHOTOLUMINESCENCE

Ca_0.99-yTb_0.01MoO₄:yEu³⁺nanophosphors weresuccessfullysynthesizedbyhydrothermal method. All the samples can be excited by 395nm wavelengths for generation of red color emission. Enhancement in ⁵D₀→⁷F₂ (616 nm) emission (f–f transition) of Eu³⁺ionis observed when Tb³⁺ionis co–doped in CaMoO₄:Eu³⁺. This is due to the efficient energy transfer from Tb³⁺ to Eu³⁺ ions. Introduction of Tb³⁺ in the system does not lead to the change of emission wavelength of Eu³⁺. However, Tb³⁺and Eu³⁺co–doped in the system induces a shift in Mo-O charge transfer band absorption from 262nm to (413–431 nm). This may be due to the increase in electronegativity between Mo and O bond in the presence of Eu³⁺andTb³⁺leading to change in crystal field environment of Mo⁶⁺ in MoO₄^{2−}. At the optimal concentration of Eu³⁺, an enhancement in emission by a factor of ∼5.6 in the respective excitation at 616nm (⁵D₀→⁷F₂) is observed. The chromaticity coordinates (CIE) of all Ca_0.99-yTb_0.01MoO₄:yEu³⁺ nanophosphors are in the red region. The luminescence lifetime values are0.812 ms to 1.20 ms. The energy transfer is observed to occur mainly via dipole–dipole interactions.