The effects of different sintering temperatures on the structure and upconversion luminescent properties of Li doped BiHoYbTiO: 0.05Li (BHYTO: Li) phosphors were investigated. The upconversion emission intensity first increases and then decreases with the increase of sintering temperature from 700 to 1000 °C. The temperature induced grain growth contributes to the enhancement of UC luminescence, but the increased defects such as Bi and O degrade the luminescence. The combined effect of them makes the optimal luminescence appears in the specimens sintered at 800 °C, which is about 2 times stronger than that of those specimens sintered at 700 and 1000 °C. The mean lifetime for the specimens sintered from 700 to 1000 °C increases monotonically from 60.2 to 81.5 μs, with band gap () from 2.8 to 3.0 eV. The maximal quantum efficiency can reach 0.28 % due to enhanced crystallinity.

中文翻译：

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热合成温度对锂掺杂Bi3.46Ho0.04Yb0.5Ti3O12:0.05Li荧光粉上转换性能的影响

研究了不同烧结温度对Li掺杂BiHoYbTiO:0.05Li(BHYTO:Li)荧光粉结构和上转换发光性能的影响。随着烧结温度从700℃升高到1000℃，上转换发射强度先增大后减小。温度诱导的晶粒生长有助于增强UC发光，但Bi和O等缺陷的增加会降低发光性能。它们的综合作用使得在800℃烧结的样品中出现最佳的发光，其强度比在700和1000℃烧结的样品强约2倍。从 700 °C 烧结到 1000 °C 的样品的平均寿命从 60.2 μs 单调增加到 81.5 μs，带隙 () 从 2.8 eV 增加到 3.0 eV。由于结晶度增强，最大量子效率可达0.28%。