Goldys Ewa M, Drozdowicz-Tomsia Krystyna, Jinjun Sun, Dosev Dosi, Kennedy Ian M, Yatsunenko Sergiey, Godlewski Marek
Division of Information and Communication Sciences, Macquarie University, Sydney 2109 NSW, Australia.
J Am Chem Soc. 2006 Nov 15;128(45):14498-505. doi: 10.1021/ja0621602.
Rare-earth-doped nanoparticles are promising materials for fluorescent labeling, as they are characterized by a high Stokes shift, narrow emission spectra, long lifetimes, minimized photobleaching, and low toxicity. We examined the structural and optical properties of europium-doped gadolinium oxide nanoparticles synthesized by the flame pyrolysis method, with specific emphasis on full spectral characterization and fluorescence kinetics. The emission-excitation characterization revealed the presence of predominantly monoclinic but also highly luminescent cubic phases with a prominent oxygen-to-europium charge-transfer band in the 230-260 nm range. A broad emission band in the visible region, corresponding to a similar band in undoped Gd(2)O(3), related to the matrix surface defects, was observed in time-gated spectroscopy of doped nanopowders. All of the examined nanopowders showed very short decay components, on the order of 2 ns, and much longer millisecond decay times characteristic of lanthanide ions. At intermediate times, on the order of 20-100 ns, a complex behavior of the decay was observed, indicative of progressive energy transfer to the lanthanide ion, which varied with different intrashell transitions. Structural characterization data by means of XRD measurements allowed for unambiguous determination of the Eu:Gd(2)O(3) crystallographic structure and cell dimensions to be consistent with a predominantly monoclinic phase.
稀土掺杂纳米粒子是用于荧光标记的有前途的材料，因为它们具有高斯托克斯位移、窄发射光谱、长寿命、最小化光漂白和低毒性等特点。我们研究了通过火焰热解法合成的铕掺杂氧化钆纳米粒子的结构和光学性质，特别强调了全光谱表征和荧光动力学。发射-激发表征显示，主要存在单斜相，但也存在高发光的立方相，在230-260纳米范围内有明显的氧到铕的电荷转移带。在掺杂纳米粉末的时间分辨光谱中，观察到可见区域的一个宽发射带，与未掺杂的Gd(2)O(3)中的类似带相对应，与基质表面缺陷有关。所有测试的纳米粉末都显示出非常短的衰减成分，约为2纳秒，以及镧系离子特有的长得多的毫秒级衰减时间。在中间时间，约为20-100纳秒时，观察到衰减的复杂行为，表明能量逐渐转移到镧系离子，这种转移随不同的壳内跃迁而变化。通过XRD测量获得的结构表征数据能够明确确定Eu:Gd(2)O(3)的晶体结构和晶胞尺寸，与主要为单斜相一致。
