Preparation and photoluminescence properties of the Sm3+, Eu3+ co-doped CaWO4 phosphors

Sm3+ and Eu3+ co-doped CaWO4 phosphors were synthesized by the solid-state reaction. The phase composition and photoluminescence properties of as-synthesized samples were characterized using X-ray power diffraction (XRD) and photoluminescence spectra (PL). The results show that their excitation spectra present strong absorption at 393 nm near-UV light and 465 nm blue light, which match well with commercial LED chips. The maximum emission peak excited under 393 nm was observed at about 615 nm due to the 5D0 → 7F2 transition of Eu3+ ions. In the Eu3+ and Sm3+ co-doped system, the intensity of the main emission peak (5D0 → 7F2 transition of Eu3+ ions) was effectively strengthened because of the energy transition from Sm3+ to Eu3+. In addition, the doping concentration of Eu3+ and Sm3+ were optimized.