Synthesis and photoluminescence enhancement of the LiLa(MoO4)2:Sm3+ red phosphors by co-doping with Bi3+ |
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| Authors: | Peng Zhou Kehui Qiu Wentao Zhang Lu Yue Sangang Lou |
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| Affiliation: | 1. College of Materials and Chemistry and Chemical Engineering, Chengdu University of Technology, Chengdu, China;2. Institute of Materials Science and Technology, Chengdu University of Technology, Chengdu, China;3. Institute of Environment, Chengdu University of Technology, Chengdu, China |
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| Abstract: | The LiLa(MoO4)2:Sm3+ and LiLa(MoO4)2:Sm3+,Bi3+ phosphors were prepared using the citric-acid-fueled combustion method and the influence of concentrations of Bi3+ dopant on LiLa(MoO4)2:Sm3+ red luminescence was investigated. The LiLa(MoO4)2:Sm3+ and LiLa(MoO4)2:Sm3+,Bi3+ samples matched well with the scheelite structure and I41/a space group and did not detect structural changes. Under an excitation of 403 nm, the prepared LiLa(MoO4)2:Sm3+,Bi3+ phosphor was excited and produced orange-red emission. When compared with the LiLa(MoO4)2:Sm3+ phosphor, the LiLa(MoO4)2:Sm3+,Bi3+ phosphor exhibited enhanced fluorescence intensity because the Bi3+ dopant ions are doped as a sensitizer. The optimal doping concentrations of Sm3+ and Bi3+ were 5 and 1 mol%, respectively. Furthermore, the energy transfer from Bi3+ to Sm3+ is effective (3P1 → 4K11/2). Subsequently, the electrons in an unstable excited state were transferred to a stable ground state (4G5/2 → 6H5/2, 6H7/2, 6H9/2). The Commission Internationale de L'Eclairage (CIE) chromaticity coordinates of the optimized LiLa(MoO4)2:Sm3+,Bi3+ phosphor were situated in the orange-red region. The luminescence of the LiLa(MoO4)2:Sm3+,Bi3+ phosphor generated under near-ultraviolet (UV) irradiation could be used to produce a warm white light, indicating its possible applications in white light-emitting diodes. |
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| Keywords: | bismuth molybdate rare earths red emission enhancement |
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