Key Laboratory of Phytochemical R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan 410081, China.
Nanoscale. 2017 Jun 29;9(25):8747-8755. doi: 10.1039/c7nr02474f.
In this work, with wavelength-resolved dark-field microscopy, the center-of-mass localization information from nanoparticle pairs (i.e., spherical (45 nm in diameter) and rod (45 × 70 nm) shaped gold nanoparticle pairs with different gap distances and orientations) was explored and compared with the results determined by scanning electron microscopy (SEM) measurements. When the gap distance was less than 20 nm, the scattering spectrum of the nanoparticle pair was seriously modulated by the plasmonic coupling effect. The measured coordinate information determined by the optical method (Gaussian fitting) was not consistent with the true results determined by SEM measurement. A good correlation between the optical and SEM measurements was achieved when the gap distance was further increased (e.g., 20, 40 and 60 nm). Under these conditions, well-defined scattering peaks assigned to the corresponding individual nanoparticles could be distinguished from the obtained scattering spectrum. These results would afford valuable information for the studies on single plasmonic nanoparticle imaging applications with the optical microscopy method such as super-localization imaging, high precision single particle tracking in a crowding environment and so on.
在这项工作中，我们通过波长分辨暗场显微镜，探索了纳米粒子对（即具有不同间隙距离和取向的球形（直径为 45nm）和棒状（45×70nm）金纳米粒子对）的质心定位信息，并将其与扫描电子显微镜（SEM）测量结果进行了比较。当间隙距离小于 20nm 时，纳米粒子对的散射光谱被等离子体耦合效应严重调制。光学方法（高斯拟合）测量的坐标信息与 SEM 测量确定的真实结果不一致。当间隙距离进一步增加（例如 20nm、40nm 和 60nm）时，光学和 SEM 测量之间达到了良好的相关性。在这些条件下，可以从获得的散射光谱中区分出对应于单个纳米粒子的明确散射峰。这些结果将为使用光学显微镜方法进行单个等离子体纳米粒子成像应用（如超局部成像、在拥挤环境中进行高精度单粒子跟踪等）的研究提供有价值的信息。
