Influence of SO42− anionic group substitution on the enhanced photoluminescence behaviour of red emitting CaMoO4:Eu3+ phosphor

CaMoO4:xEu3+(x = 0.5, 1.0, 1.5, 2.0, and 2.5) powder phosphors incorporating SO42− anions were synthesized at high temperature using the solid-state reaction technique. The structural, morphological and optical properties of these phosphors were analysed using X-ray diffraction (XRD), field emission scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and optical spectroscopy. The XRD results indicate that the incorporation of SO42− anions and Eu3+ dopant ions did not affect the crystal structure of the CaMoO4, but largely influenced the luminescence properties of the CaMoO4–SO4:Eu3+ phosphors.The optical properties of our materials were examined using the UV–vis absorption spectroscopy. The absorption edges of the phosphors with different concentrations of Eu3+ were less than the band gap energy of the CaMoO4 and their values ranged from 3.30 to 4.75 eV. The intensity of the red photoluminescence (PL) from CaMoO4:Eu3+ phosphors was enhanced considerably upon incorporation of SO42− anions, suggesting that SO42− acted to capture primary excitation energy and transfer it non-radiatively to Eu3+ ions. In addition, the incorporation of SO42− ions also improved the fluorescence decay life-time values of the CaMoO4:xEu3+ phosphors significantly. Tunable emission was observed when the Eu3+ concentration was varied. Our PL results indicated that the CaMoO4–SO4:Eu3+ phosphor exhibited the highest red emission intensity compared to CaMoO4: Eu3+ phosphors, suggesting that CaMoO4–SO4:Eu3+ could be a promising red component material for potential application in white light-emitting diode devices. [Display omitted] •CaMoO4:Eu3+ phosphors substituted with SO42− groups were prepared via solid state reaction method.•Photoluminescence (PL)properties of CaMoO4:Eu3+ were improved by SO42− ions.•The energy transfer from MoO42− to Eu3+ was showed in CaMoO4 host.•Orange-red to red color tuneable emission has been achieved by the SO42− substitution.•CaMoO4–SO4:Eu3+ are potential candidates for UV excited red emission LED applications.