The photoluminescence properties of Ba 0.95− xM xB 8O 13:Eu 3+ (M = Ca, Sr, 0 ≤ x ≤ 0.1) in 100–400 nm regions

Abstract

The phosphors Ba 0.95 − x M x B 8O 13:Eu 3+ (M = Ca, Sr, 0 ≤ x ≤ 0.1) were synthesized by solid-state reaction. Their luminescent properties were studied under ultraviolet (UV) and vacuum ultraviolet (VUV) regions. The excitation spectrum of Ba 0.95Eu 0.05B 8O 13 showed that the charge transfer (CT) excitation band of Eu 3+ at about 246 nm was dominated in the UV region, while two weak broad bands of the host lattice absorption with maxima at 157 and 183 nm were observed in the VUV region. The band of Ba–O absorption was overlapped with the CT band of Eu 3+, which is indicated that the energy of the host lattice absorption can be efficiently transfer to the Eu 3+. With the incorporation of Sr 2+ into BaB 8O 13:Eu 3+ lattice, the CT band of Eu 3+ as well as the band absorption of the host lattice were enhanced. For Ca 2+ co-doped BaB 8O 13:Eu 3+, the excitation intensity was decreased, as well as the CT band showed a little blue-shift. The intense red emission located at 612 nm and the improved luminescent intensity of Eu 3+ were observed when Ba 2+ was replaced by Sr 2+ partially in the BaB 8O 13:Eu 3+ lattice, while the incorporation of Ca 2+ ions do not show efficient luminescence and the main emission line shift to 588 nm. The shift in CT band of Eu 3+ could be explained by the cation structures of borate have an influence on the electron transfer and the energy of the CT band of Eu 3+ in the host lattice.