Y2O3：Eu^3＋电荷迁移激发光谱的纳米效应

利用低温燃烧法合成Y2O3：Eu^3＋体相及纳米粉体材料，通过XRD图谱和电荷迁移（CT）激发光谱测定粉体的平均尺寸、电荷迁移能及CT激发光谱能量跨度。在理论分析与实验验证的基础上，探讨Y2O3：Eu^3＋发光材料的纳米化对电荷迁移（CT）激发所需电荷迁移能的影响。结果表明：在Y2O3：Eu^3＋材料发光中心CT激发的谐振子模型中，发光中心的振动频率ω（基态）及ω’（CT态）将随材料纳米尺寸的下降而下降；CT激发光谱能量跨度Espan以及CT激发中发光中心所获得的振动能量Evib将随CT态振动频率ω’的下降而下降；此外，基于发光中心零声子电荷迁移能Ezp以及发光中心振动能量Evib随Y2O3：Eu^3＋纳米尺寸的下降幅度，求得CT激发所需电荷迁移能ECt的变化幅度，所得结果与实验测量值基本相符。该文揭示了Y2O3：Eu^3＋材料纳米化后CT激发能的下降以及CT激发光谱能量跨度的收缩机理，具有一定的理论和实际意义。

Study on CT excitation spectrum for nano-sized Y2O3: Eu3+

This paper describes the preparation of Y2O3：Eu^3＋ bulk and nano-sized powder phosphor in glycine-nitrate combustion synthesis, the determination of the average size of the phosphor, the charge transfer（CT） energy and the energy span of CT excitation spectrum using XRD data and measurement of CT excitation spectra, and the investigation into the size effects of the phosphor on CT energy based on theoretical analysis and experiments. Results show that, in the harmonic oscillator mode of an optical center in CT excitation, the vibration frequency to（in ground state） and ω＇（ in CT state） tends to decrease with the decrease of nano-sized Y2O3：Eu^3＋- The vibration energy Evib of an optical center obtained in CT excitation and the shrinkage in energy span Espan of CT excitation spectrum tends to decrease with the decrease of vibration frequency ω＇. The zero-phonon CT energy Ezp tends to decrease with the decrease of phosphor size in nano-scale. The changing magnitude in CT energy ECT obtained, based on the changes in Ezp and Evib, is basically consistent with that measured in the experiment. The paper highlights the mechanisms on the decrease of CT energy and the shrinkage in energy span of CT excitation spectrum and concludes that the research is of some theoretical and practical importance.