Surface treatment investigation and luminescence properties of SiO2-coated Ca2BO3Cl:0.02Eu2+ phosphors via sol–gel process

SiO2-coated Ca2BO3Cl:Eu2+ phosphors were prepared by the sol–gel method in order to enhance the chemical and thermal stabilities of Ca2BO3Cl:Eu2+ phosphor. The phase structures, microstructures and luminescence properties were studied by the X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrometer, respectively. The emission intensity of SiO2-coated Ca2BO3Cl:Eu2+ phosphor decreased a little compared to that of the uncoated phosphor. The moisture resistances of the phosphors were comparatively examined by the aging treatment experiment in the water, and the thermal stability was studied by the temperature dependent photoluminescence spectra. The results indicated that SiO2 coating on the surface of the phosphor particles improved the moisture-resistance and thermal stability to a large extent.

► Sol–gel processing method was used to form the SiO2 layer on the powder surfaces.
► SiO2-coated Ca2BO3Cl:Eu2+ phosphors with good stability were obtained.
► The water-resistance stability was improved based on the pH variation analysis.
► Temperature dependent emission spectra testified the good thermal stability.