Jiang Yingyan, Su Hua, Wei Wei, Wang Yongjie, Chen Hong-Yuan, Wang Wei
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China.
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
Proc Natl Acad Sci U S A. 2019 Apr 2;116(14):6630-6634. doi: 10.1073/pnas.1820114116. Epub 2019 Mar 14.
While rotational dynamics of anisotropic nanoobjects has often been limited in plasmonic and fluorescent nanomaterials, here we demonstrate the capability of a surface plasmon resonance microscopy (SPRM) to determine the orientation of all kinds of anisotropic nanomaterials. By taking CdS nanorods as an example, it was found that two-dimensional Fourier transform of the asymmetrical wave-like SPRM image resulted in a peak in its angular spectrum in space. Consistency between the peak angle and the geometrical orientation of the nanorod was validated by both in situ scanning electron microscope characterizations and theoretical calculations. Real-time monitoring of the rotational dynamics of single CdS nanorods further revealed the accelerated rotation under appropriate reaction conditions for photocatalyzed hydrogen generation. The driving force was attributed to the asymmetric production of hydrogen molecules as a result of inhomogeneous distribution of reactive sites within the nanorod. The present work not only builds the experimental and theoretical connections between the orientation of anisotropic nanomaterials and its SPRM images; the general suitability of SPRM also sheds light on broad types of nonfluorescent and nonplasmonic anisotropic nanoobjects from semiconductors to bacteria and viruses.
虽然各向异性纳米物体的旋转动力学在等离子体和荧光纳米材料中常常受到限制，但在此我们展示了表面等离子体共振显微镜（SPRM）确定各类各向异性纳米材料取向的能力。以硫化镉纳米棒为例，发现不对称波状SPRM图像的二维傅里叶变换在空间角谱中产生一个峰值。通过原位扫描电子显微镜表征和理论计算验证了峰值角度与纳米棒几何取向之间的一致性。对单个硫化镉纳米棒旋转动力学的实时监测进一步揭示了在光催化产氢的适当反应条件下其加速旋转。驱动力归因于纳米棒内反应位点不均匀分布导致的氢分子不对称产生。本工作不仅建立了各向异性纳米材料取向与其SPRM图像之间的实验和理论联系；SPRM的普遍适用性还为从半导体到细菌和病毒等广泛类型的非荧光和非等离子体各向异性纳米物体提供了启示。
