Luminescence enhancement of CaMoO₄:Eu³⁺ phosphor by charge compensation using microwave sintering method

CaMoO₄:Eu³⁺ and CaMoO₄:Eu³⁺,A⁺ (A=Li, Na, K) phosphors for light-emitting diode (LED) applications have been prepared by microwave sintering method (MSM), and their structure and luminescence properties are investigated. The influences of microwave reaction time and concentration of different kinds of charge compensation A⁺ and Eu³⁺ on luminescence have also been discussed. The samples emit a red luminescence at 615 nm attributed to the ⁵D₀→⁷F₂ transition of Eu³⁺ under 464 nm excitation. It is observed that adding charge compensation A⁺ in the sample synthesis increases luminescence intensity. The optimized sample made with 32 mol% Li⁺ and 32 mol% Eu³⁺ has an enhancement factor of 4 in photoluminescence compared to the sample made without charge compensation. The CIE (Commission Internationale de l´Eclairage) coordinates of Ca_0.36MoO₄:0.32Eu³⁺,0.32Li⁺ are x=0.661 and y=0.339, which indicate that the obtained phosphor can be a promising red color candidate for white LED fabrications.