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通过调控Mn2+的掺杂浓度,在镥基纳米晶体成功地实现了六方、四方混合相到纯四方相的相位转变,并详细讨论了其相变机理.时域和频域光谱的分析表明,立方相Na5Lu9F32:40%Mn2+,20%Yb3+,2%Ln3+(Ln=Er3+,Ho3+)纳米晶体内的准纯红色荧光发射主要由Mn2+和Ln3+之间的两步能量转移引起.Mn2+掺杂后引起了发光离子附近局域对称性的降低,使得电偶极跃迁的辐射速率明显增加,进而导致了上转换、下转换荧光的极大增强.该研究结果在生物荧光成像、太阳能电池效率的提高方面具备潜在的、广阔的应用前景.
By controlling the doping concentration of Mn2 +, the phase transition from hexagonal to tetragonal mixed phase to pure tetragonal phase was successfully achieved in 镥-based nanocrystals, and the phase transition mechanism was discussed in detail. The analysis of time-domain and frequency- The quasi-pure red fluorescence emission in nanocrystals of Na5Lu9F32: 40% Mn2 +, 20% Yb3 +, 2% Ln3 + (Ln = Er3 +, Ho3 +) is mainly caused by the two-step energy transfer between Mn2 + and Ln3 + The reduction of the local symmetry near the luminescent ions leads to a significant increase of the radiation rate of the electric dipole transition, which in turn leads to the great enhancement of the up-conversion and down-conversion fluorescence. The results of this study are available in bio-fluorescence imaging and solar cell efficiency improvement Potential, broad application prospects.