Delage-Laurin Leo, Nelson Zachary, Swager Timothy M
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Institute for Soldier Nanotechnologies, Cambridge, Massachusetts 02139, United States.
ACS Appl Mater Interfaces. 2021 Jun 2;13(21):25137-25142. doi: 10.1021/acsami.1c04769. Epub 2021 May 19.
The Faraday effect is a magneto-optical (MO) phenomenon that causes the plane of linearly polarized light to rotate when passing through a medium subjected to a parallel magnetic field. Informed by the established quantum mechanical model developed by Buckingham and Stephens, we sought to identify molecules that would exhibit large MO responses. Magnetic circular dichroism studies of ferrocenium in the 1970s revealed its potential as an MO material; however, it has not been evaluated in the context of Faraday rotation and thin-film optical applications. Herein, we report near-infrared (NIR) Faraday rotation in thin films of decamethylferrocenium/poly(methyl methacrylate) composites with maximum Verdet constants of -3.45 × 10 deg T m at 810 nm (absorbance = 0.09) and -1.44 × 10 deg T m at 870 nm (absorbance = 0.01). These polymer-metallocene thin films deliver larger Verdet constants than commercially used NIR inorganic Faraday rotators and are facile and inexpensive to produce. The temperature dependence and distinct lineshape of the MO responses observed in decamethylferrocenium radical cations, decamethylmanganocene, and chromocene are in accordance with the quantum mechanical model. The observation of a strong C-term Faraday rotation in solid-state organometallic materials provides the groundwork for the development of high-performance metallocene-based Faraday rotators.
法拉第效应是一种磁光（MO）现象，当线偏振光穿过处于平行磁场中的介质时，会导致其偏振面发生旋转。基于白金汉和斯蒂芬斯建立的量子力学模型，我们试图识别出具有较大MO响应的分子。20世纪70年代对二茂铁鎓的磁圆二色性研究揭示了其作为MO材料的潜力；然而，尚未在法拉第旋转和薄膜光学应用的背景下对其进行评估。在此，我们报告了十甲基二茂铁/聚（甲基丙烯酸甲酯）复合材料薄膜中的近红外（NIR）法拉第旋转，在810nm处最大韦尔代常数为-3.45×10⁻² deg T⁻¹ m（吸光度 = 0.09），在870nm处为-1.44×10⁻² deg T⁻¹ m（吸光度 = 0.01）。这些聚合物 - 金属茂薄膜提供的韦尔代常数比商业使用的近红外无机法拉第旋转器更大，并且制备简便、成本低廉。在十甲基二茂铁自由基阳离子、十甲基锰茂和二茂铬中观察到的MO响应的温度依赖性和独特线形与量子力学模型一致。在固态有机金属材料中观察到的强C项法拉第旋转为开发高性能的基于金属茂的法拉第旋转器奠定了基础。
