School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT, UK.
Nanotechnology. 2012 Feb 10;23(5):055701. doi: 10.1088/0957-4484/23/5/055701. Epub 2012 Jan 11.
Bimetallic Pd-Au particles synthesized using Desulfovibrio desulfuricans bacteria are characterized using scanning transmission electron microscopy (STEM) with a high-angle annular dark field (HAADF) detector combined with energy dispersive x-ray (EDX) silicon drift detector (SDD) elemental mapping and plasmon electron energy-loss spectroscopy (EELS). When combined with EDX, theoretical considerations or EELS, the atomic-number contrast (Z-contrast) provided by HAADF-STEM is effective in characterizing the compositional configuration of the bimetallic nanoparticles. Homogeneous mixing and complex segregations have been found for different particles in this work. The EELS study has also found different behaviours corresponding to surface plasmon resonances in different regions of a single particle due to its heterogeneity and anisotropy. HAADF-STEM tomography has been performed to obtain three-dimensional (3D) visualization of the nanoparticles.
使用脱硫弧菌合成的双金属 Pd-Au 粒子，采用扫描透射电子显微镜（STEM）结合高角度环形暗场（HAADF）探测器以及能量色散 X 射线（EDX）硅漂移探测器（SDD）元素图谱和等离激元电子能量损失谱（EELS）进行了表征。当与 EDX 结合使用时，HAADF-STEM 提供的原子序数对比（Z-contrast）在表征双金属纳米粒子的组成结构方面非常有效。在这项工作中，我们发现不同粒子存在均匀混合和复杂偏析的情况。EELS 研究还发现，由于单粒子的不均匀性和各向异性，在其不同区域对应于表面等离激元共振存在不同的行为。进行了 HAADF-STEM 断层扫描，以获得纳米粒子的三维（3D）可视化。
