Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China.
Nanoscale. 2011 Aug;3(8):3164-9. doi: 10.1039/c1nr10341e. Epub 2011 Jun 16.
Monodisperse cubic-phase KYF(4) : Eu(3+) nanocrystals (NCs) were synthesized via a modified thermal decomposition method. The optical properties of Eu(3+) in KYF(4) NCs including multiple luminescence centers, site symmetry, luminescence dynamics, as well as crystal-field levels of Eu(3+) were investigated in detail based on high-resolution photoluminescence (PL) spectroscopy at low temperature (10 K). Different from Eu(3+) in bulk counterparts, multiple sites of Eu(3+) in KYF(4) NCs were revealed by using the luminescence of Eu(3+) as a sensitive structural probe. The highest site symmetry of Eu(3+) at new near-surface site was deduced to be distorted from O(h) to D(2) (or C(2v)). Due to a small filling factor (0.45) of NCs, the PL lifetime of (5)D(0) of Eu(3+) in KYF(4) NCs was much longer than that in bulk counterparts, which was found to be significantly affected by the surrounding medium around the NCs.
通过改进的热分解法合成了单分散立方相 KYF(4)：Eu(3+)纳米晶体 (NCs)。基于低温（10 K）下的高分辨率光致发光 (PL) 光谱，详细研究了 Eu(3+)在 KYF(4) NCs 中的多个发光中心、点群对称性、发光动力学以及 Eu(3+)的晶体场能级。与体相中的 Eu(3+)不同，通过使用 Eu(3+)的发光作为灵敏的结构探针，揭示了 KYF(4) NCs 中 Eu(3+)的多个位点。新的近表面位点上 Eu(3+)的最高点群对称性推断为从 O(h)到 D(2)（或 C(2v)）的畸变。由于 NCs 的填充因子 (0.45) 较小，Eu(3+)在 KYF(4) NCs 中的 (5)D(0) 的 PL 寿命比体相中的寿命长得多，发现它受到 NCs 周围环境的显著影响。
