D'Achille Anne E, Wallace Robert M, Coffer Jeffery L
Department of Chemistry and Biochemistry, Texas Christian University Ft. Worth TX. 76129 USA
Department of Materials Science and Engineering, University of Texas at Dallas Dallas TX 75080 USA.
Nanoscale Adv. 2021 Apr 28;3(12):3563-3572. doi: 10.1039/d1na00096a. eCollection 2021 Jun 15.
Europium-doped CeO nanomaterials have been investigated for a variety of sensing and biological applications, as doping enhances the catalytic activity of CeO and contributes visible fluorescence to the nanomaterial. However, scant evidence is available that directly compares Eu fluorescence from multiple morphologies establishing useful correlation(s) between physical and optical trends in such structures. To address this shortcoming, Eu-doped CeO nanorods, nanowires, nanocubes, and annealed nanorods were synthesized and characterized, representing a range of crystalline defect sizes, defect concentrations, and surface moieties. Morphologies rich with oxygen defects and hydroxyl groups (assessed X-ray photoelectron spectroscopy) quenched the Eu fluorescence, while samples with larger crystalline domains and lower Ce concentrations have relatively stronger emission intensities. Of the four morphologies, nanocubes exhibit the strongest emission, as each structure is monocrystalline with few oxygen defects and associated quenching sites. Furthermore, the Eu hypersensitive transition is more responsive to the dopant concentration in the nanocubes, as defects induced by the dopant are not removed by thermal annealing.
掺铕的CeO纳米材料已被用于多种传感和生物应用研究，因为掺杂可增强CeO的催化活性并使纳米材料产生可见荧光。然而，几乎没有证据能直接比较多种形态的铕荧光，从而在此类结构的物理和光学趋势之间建立有用的关联。为弥补这一缺陷，合成并表征了掺铕的CeO纳米棒、纳米线、纳米立方体和退火纳米棒，它们代表了一系列晶体缺陷尺寸、缺陷浓度和表面部分。富含氧缺陷和羟基的形态（通过X射线光电子能谱评估）会淬灭铕荧光，而具有较大晶域和较低铈浓度的样品具有相对较强的发射强度。在这四种形态中，纳米立方体表现出最强的发射，因为每个结构都是单晶，几乎没有氧缺陷和相关的淬灭位点。此外，铕的超灵敏跃迁对纳米立方体中的掺杂剂浓度更敏感，因为掺杂剂引起的缺陷不会通过热退火去除。
