Enhanced luminescence in CaMoO₄: Eu³⁺ red phosphor nanoparticles prepared by mechanochemically assisted solid state meta-thesis reaction method

For the first time, CaMoO₄: xEu³⁺ (x = 0.02, 0.04, 0.06, 0.08, 0.1) red phosphor nanoparticles were synthesized using the simple mechanochemically assisted solid state meta-thesis (SSM) reaction method and the luminescence properties as a function of Eu³⁺ ion concentration was investigated. The characteristics of the phosphor materials were analyzed using X-ray diffraction, fourier transform infrared spectroscopy, photoluminescence (PL) and diffuse reflectance spectroscopy. For 8 mol% of Eu³⁺ concentration, the phosphor shows an intensified excitation peak at 392 nm indicating a strong absorption. The PL emission spectra of CaMoO₄: Eu³⁺ phosphors showed an intense peak at 615 nm (red) which corresponds to ⁵D₀ → ⁷F₂ transition of Eu³⁺. The optimal Eu³⁺ concentration in CaMoO₄ phosphors for enhanced red emission occurs for 8 mol% and above this concentration, the emission intensity decreases due to quenching effect. The CIE colour coordinates of the CaMoO₄: 0.08Eu³⁺ red phosphor coincide very well with the standard values of NTSC. The red emission intensity of the SSM prepared CaMoO₄: 0.08Eu³⁺ red phosphor is 4.7 times greater than that of the commercial Y₂O₂S: Eu³⁺ red phosphor and 1.6 times more than the same phosphor prepared by the solid state reaction method.