纳米发光材料电荷迁移激发光谱的红移机理研究

基于Kronig-Penney模型，得出了晶体材料禁带宽度 或特定能级 在禁带中的位置随着晶体体积畸变而变化的趋势，进而推断出Y2O3:Eu3+发光材料的零声子电荷迁移能 将随着材料纳米尺寸的下降而下降。此外，Y2O3:Eu3+纳米发光材料晶格环境刚性的下降导致了发光中心CT态坐标偏差的增大，这意味着在电荷迁移(CT)激发中发光中心将跃迁至更高的振动能级。随着Y2O3:Eu3+发光材料纳米尺寸的下降，振动能 的上升幅度小于零声子电荷迁移能 的下降幅度，电荷迁移能ECT由此下降，CT激发光谱向低能端移动。

Theoretical investigation on red shift of charge transfer excitation spectrum for nano-sized phosphors

Based on Kronig-Penney model, the changing tendency of band gap or a particular level with the volume deformation in crystalline materials has been derived. On the basis of this changing tendency, the zero-phonon CT energy is deduced to be decreased when the size of Y2O3:Eu3+ phosphor decreases in nano-scale. In addition, the rigidity decrease of lattice environment in Y2O3:Eu3+ nano-phosphor leads to the enlargement of CTS coordinate offset, an optical center would reach a higher vibration level in CT excitation. The increasing magnitude in is smaller than the decreasing magnitude of when the size of Y2O3:Eu3+ phosphor decreases in nano-scale. As a result, the CT energy is decreased, and the CT excitation spectrum shifts to lower energy.