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In this paper, MAl 2 Si x O 2x+4 :Eu 2+ /Eu 3+ (Eu 2+ + Eu 3+ = 2%, molar ratio; M = Mg, Ca, Sr, Ba; x = 0, 0.5, 1, 1.5, 2) phosphors with different SiO 2 concentrations (the ratio of SiO 2 to MAl 2 O 4 is n%, n = 0, 50, 100, 150, 200, respectively) were prepared by high-temperature solid-state reaction under atmospheric air conditions. Their structures and photoluminescent properties were systematically researched. The results indicate that Eu 3+ ions have been reduced and Eu 2+ ions are obtained in air through the self-reduction mechanism. The alkaline earth metal ions and doping SiO 2 strongly affect the crystalline phase and photoluminescent properties of samples, including microstructures, relative intensity of Eu 2+ to Eu 3+ , location of emission lines/bands. It is interesting and important that the emission color and intensities of europium-doped various phosphors which consist of aluminosilicate matrices prepared under atmospheric air conditions could be modulated by changing the kinds of alkaline earth metal and the content of SiO 2 ., (Copyright © 2017 John Wiley & Sons, Ltd.)

In this paper, the CaMoO4:Eu3+ phosphors were prepared by a simple hydrothermal method assisted by the citric acid as the surfactant, and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and fluorescent spectrophotometry. The results of XRD show that the as-prepared samples are single phase. The process of the Ostwald ripening is controlled by the content of the citric acid in the hydrothermal reaction. The pH value of the precursor affects the shift of the charge transition band (CTB) in the excitation spectra. The reaction condition can strongly affect the luminescent intensity of the samples.