Tunable emission color of Li2SrSiO4:Tb3+ due to cross‐relaxation process and optical thermometry investigation |
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| Authors: | Xiao Zhou Sha Jiang Guotao Xiang Xiao Tang Xiaobing Luo Li Li Xianju Zhou |
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| Affiliation: | School of Science, Chongqing University of Posts and Telecommunications, Chongqing, China |
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| Abstract: | A series of Li2SrSiO4:xTb3+ (0.2%, 0.4%, 0.6%, 0.8%, 2%, 4%, and 6%) phosphors were prepared by conventional solid‐state reaction. It was found that this silicate phosphor has a wide excitation band at near‐ultraviolet region (230‐300 nm) due to spin‐allowed 4f 8→4f75d1 transitions of Tb3+ ions, with the exact position dependent on the crystal field of the lattice. The cross‐relaxation process originating from 5D3→5D4 and 7F6→7F0 happened between different Tb3+ ions. It leads to the luminescence color of Li2SrSiO4: xTb3+ tuning from blue to green just by controlling Tb3+ concentrations. Furthermore, concentration quenching mechanism, energy migration type, cross‐relaxation rate and efficiency, are discussed in detail. Finally, optical thermometry properties were investigated via temperature‐dependent emission spectra. The results show that low‐concentration‐doped sample (Li2SrSiO4:0.4%Tb3+) shows remarkable optical thermometry based on fluorescence intensity ratio (FIR) between the blue and green emission of Tb3+ ions, whereas the high‐concentration‐doped sample (Li2SrSiO4:4%Tb3+) demonstrates small emission intensity loss. It illustrates that terbium‐doped silicate phosphor is a multifunctional material with potential application for display field and optical thermometry . |
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| Keywords: | concentration quenching cross relaxation optical thermometry silicate phosphor tunable emission |
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