MoNOS, Huygens Laboratorium, Universiteit Leiden, The Netherlands.
Phys Chem Chem Phys. 2012 Apr 7;14(13):4584-8. doi: 10.1039/c2cp24092k. Epub 2012 Feb 27.
We present measurements of the polarized extinction of gold nanorod suspensions exposed to an external electric field. By employing an amplitude modulated field in combination with lock-in detection we resolve changes in the optical density as low as 10(-6) in an integration time of 10 s. This sensitivity allows us to probe the partial alignment of small gold nanorods with an aspect ratio of 2.5 and a width ranging from 13 nm to 28 nm. The degree of orientation scales as the square of the electric field strength, as expected for an induced dipole moment in an external field. By varying the modulation frequency we measure the rotation diffusion constant of different samples, which are in excellent agreement with the calculated values for a short cylinder.
我们展示了暴露于外电场的金纳米棒悬浮液的偏振消光测量结果。通过采用振幅调制场并结合锁相检测，我们在 10 秒的积分时间内分辨出低至 10(-6)的光密度变化。这种灵敏度使我们能够探测到具有 2.5 纵横比和 13nm 至 28nm 宽度的小金纳米棒的部分排列。取向度与电场强度的平方成正比，这与外场中感应偶极矩的预期结果一致。通过改变调制频率，我们测量了不同样品的旋转扩散常数，其与短圆柱的计算值非常吻合。
