Abstract
Vacuum ultraviolet (VUV) spectroscopic properties of rare-earth RE3+- activated (RE3+ = Sm3+, Eu3+, Tb3+ and Dy3+) Ba6Gd9B79O138 borates (BGBO) are investigated. The strong absorption bands in the VUV range of un-doped and RE3+-activated BGBO were observed. The band range from 140 to 200 nm with a peak at about 173 nm results from the host lattice absorption. For Sm3+-activated BGBO, the charge transfer transition from O2- to Sm3+ was observed at 202 nm. In addition, it exhibits bright red emission originating from the Sm3+ f-f transitions of 4G5/2 → 6HJ (J = 5/2, 7/2 and 9/2). The O2--Eu3+ charge transfer (CT) at 249 nm is observed in the excitation spectrum for Eu3+-doped BGBO. For Tb3+-activated BGBO, the broad bands around 208 and 230 nm are due to the spin-allowed and spin-forbidden f-d transitions of Tb3+, respectively. In addition, the absence of the f-d transitions of Sm3+ and Dy3+ in the excitation spectra probably due to the photo-ionization effect. It is demonstrated that there are energy transfers from the BGBO host lattice to the luminescent activators depending on the activators.
Original language | English |
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Pages (from-to) | 69-75 |
Number of pages | 7 |
Journal | Solid State Sciences |
Volume | 64 |
DOIs | |
State | Published - 1 Feb 2017 |
Keywords
- Borate
- Luminescence
- Rare-earth
- VUV