Structural and luminescence properties of europium oxide and dysprosium oxide codoped strontium borophosphate ceramics

Abstract

A series of Eu3+ and Dy3+ co-doped strontium borophosphate ceramics were synthesized using solid-state reaction method at 1000 oC for 4 hours. The influence of strontium oxide composition on structural features of the borophosphate ceramics were investigated by using FT-IR spectroscopy. The addition of higher strontium oxide composition into the host ceramics matrix leads to an increase in ceramic network polymerization due to the replacement of bridging oxygen bonds by non-bridging oxygen bonds. The crystalline phases of ceramics were characterized by X-ray diffraction (XRD). XRD pattern revealed that strontium borophosphate ceramic existed in polycrystalline structure. Optimum composition was chosen from strontium borophosphate series based on the XRD and photoluminescence analysis. Eu and Dy were used as activator to enhance photoluminescence emission. The optimum composition determined from this study is 10SrO-40B2O3-50P2O5 codoped with 2 mol% of Eu3+ and 1 mol% of Dy3+. The result of this study shows that photoluminescence emission and UV excitation due to energy transfer occurred within Dy3+-Eu3+ pair ions under 350 nm and 394 nm excitation separately. The energy transfer between Dy3+ and Eu3+ takes place through resonant energy transfer mechanism. The prominent emission peaks of Eu3+ and Dy3+ co-activated strontium borophopshate ceramics were 484 nm, 574 nm, 613 nm, 660 nm and 697 nm which were assigned to transition of 4F9/2 ? 6H15/2, 4F9/2 ? 6H13/2, 5D0 ? 7F2, 4F9/2 ? 6F11/2, and 5D0 ? 7F4. Prominent hypersensitive dipole transition was affected by structural surrounding environment of activators and polycrystalline structural network. This study shows that a new polycrystalline strontium borophosphate ceramics doped with Eu and Dy is suitable for luminescent materials.