Synthesis and photoluminescence study of Ce³⁺ ion-activated Na₂ZnP₂O₇ and Na₄P₂O₇ pyrophosphate phosphors

Abstract

The Ce³⁺ ion-doped Na₂ZnP₂O₇ and Na₄P₂O₇ pyrophosphate phosphors were prepared for the first time via wet chemical method in the history of phosphors. We focused our studies on photoluminescence property of these inorganic solids. In addition, their structural, morphological, spectroscopic, and thermoluminescence properties were also systematically studied and well analyzed. The emission spectra of Ce³⁺ ion-doped Na₂ZnP₂O₇ and Na₄P₂O₇ phosphors show a broad band in the ultra violet (UV) spectral region due to the presence of 4f–5d transitions of Ce³⁺ ions. The interesting luminescence properties of these phosphors can make them to be attractive candidates for the application in various fields of luminescence. We reported that at higher concentration of cerium, the cluster formation increases due to ion interaction leading to quenching of the Ce³⁺ fluorescence. Their XRD was studied for testing the phase purity and crystallinity. SEM gives the particles of a quadrate shape with an average diameter of 1–5 µm, which suggests that the phosphors can be used to fabricate the solid-lighting devices. FT-IR spectra of these pyrophosphates give information regarding the internal and external modes of P₂O₇⁴⁻group and metal–oxygen vibrations. Thermoluminescence property of only Na₄P₂O₇ phosphor using γ-irradiated by ⁶⁰Co source was reported, whereas Na₂ZnP₂O₇ phosphor was found unfavorable in showing TL behavior. Numbers of solid phosphate materials have been synthesized and many still remain to be discovered. They are generally long-lasting, safe, and have a varied range of definite and potential materials applications.