Fluorescence-Detected Circular Dichroism of a Chiral Molecular Monolayer with Dielectric Metasurfaces
Fluorescence-Detected Circular Dichroism of a Chiral Molecular Monolayer with Dielectric Metasurfaces
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DOI：
10.1021/jacs.0c07140
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发表时间：
2020-10-28
影响因子：
15
通讯作者：
Dionne, Jennifer A.
中科院分区：
文献类型：
--
作者：
Solomon, Michelle L.;Abendroth, John M.;Dionne, Jennifer A.
分子圆二色性（CD）的增强有可能实现高效的不对称光解，这是一种传统的手性分离方法，由于产率不足和对映体过剩低而受到阻碍。在这里，我们实验研究了如何预测共振硅纳米片附近光学手性密度的增强，从而提高CD。我们使用荧光检测圆二色性（FDCD）光谱间接测量了被功能化为硅纳米片阵列的光活性分子单层对圆偏振光的微分吸收。重要的是，分子和纳米盘天线具有光谱一致的共振，我们的荧光技术使我们能够将纳米盘中的吸收从分子中解卷积。我们发现增强的FDCD信号依赖于纳米光子共振，与模拟的微分吸收和光手性密度很好地一致，而从无特征硅表面上吸附的分子中检测不到信号。这些结果验证了纳米光子平台在低能量要求下用于不对称光解的潜力。
Strong enhancement of molecular circular dichroism (CD) has the potential to enable efficient asymmetric photolysis, a method of chiral separation that has conventionally been impeded by insufficient yield and low enantiomeric excess. Here, we study experimentally how predicted enhancements in optical chirality density near resonant silicon nanodisks boost CD. We use fluorescence-detected circular dichroism (FDCD) spectroscopy to measure indirectly the differential absorption of circularly polarized light by a monolayer of optically active molecules functionalized to silicon nanodisk arrays. Importantly, the molecules and nanodisk antennas have spectrally coincident resonances, and our fluorescence technique allows us to deconvolute absorption in the nanodisks from the molecules. We find that enhanced FDCD signals depend on nanophotonic resonances, in good agreement with simulated differential absorption and optical chirality density, while no signal is detected from molecules adsorbed on featureless silicon surfaces. These results verify the potential of nanophotonic platforms to be used for asymmetric photolysis with lower energy requirements.