Tian Xiu-Na, Jiang Gui-Cheng, Wei Xian-Tao, Wu Ling-Yuan, Li Shuo, Deng Kai-Mo, Chen Yong-Hu, Yin Min
J Nanosci Nanotechnol. 2014 Jun;14(6):4490-4. doi: 10.1166/jnn.2014.8053.
NaYF4:Eu3+ core and NaYF4:Eu3+/NaYF4 core/shell nanocrystals (NCs) were synthesized via a wet chemical method. The transmission electron microscope photographs show that the core and core/shell nanoparticles are monodisperse and uniform NCs with average diameters of 22 and 26 nm respectively. The photoluminescence (PL) properties of the samples, including the PL excitation and emission spectra, and luminescent decay curves, are investigated in detail. The results show that the intensity of 5D2 emission relative to that of 5D0 is stronger in NaYF4:Eu3+/NaYF4 core/shell NCs than that in NaYF4:Eu3+ core NCs, and a longer decay lifetime of 5D2 is observed in core/shell samples. In addition, from the corrected emission spectra of 5D0, the 5D0 radiative lifetimes were calculated. These together with the measured decay lifetime of 5D0 emission give the intrinsic quantum yields of 5D0. The results were well interpreted by considering the surface effects.
通过湿化学法合成了NaYF4:Eu3+核以及NaYF4:Eu3+/NaYF4核壳纳米晶体（NCs）。透射电子显微镜照片显示，核以及核壳纳米颗粒为单分散且均匀的纳米晶体，平均直径分别为22纳米和26纳米。详细研究了样品的光致发光（PL）特性，包括PL激发和发射光谱以及发光衰减曲线。结果表明，与NaYF4:Eu3+核纳米晶体相比，NaYF4:Eu3+/NaYF4核壳纳米晶体中5D2发射相对于5D0发射的强度更强，并且在核壳样品中观察到5D2具有更长的衰减寿命。此外，根据5D0的校正发射光谱计算了5D0辐射寿命。这些与测量的5D0发射衰减寿命一起给出了5D0的本征量子产率。通过考虑表面效应，对结果进行了很好的解释。
