摘要
Generation of circular dichroism （CD） beyond the UV region is of great interest in developing chiral sensors and chiroptical devices. Herein, we demonstrate a simple and versatile method for fabrication of plasmonic oligomers with strong CD response in the visible and near IR spectral range. The oligomers were fabricated by triggering the side-by-side assembly of cysteine-modified gold nanorods. The modified nanorods themselves did not exhibit obvious plasmonic CD signals; however, the oligomers show strong CD bands around the plasmon resonance wavelength. The sign of the CD band was dictated by the chirality of the absorbed cysteine molecules. By adjusting the size of the oligomers, the concentration of chiral molecules, and/or the aspect ratio of the nanorods, the CD intensity and spectral range were readily tunable. Theoretical calculations suggested that CD of the oligomers originated from a slight twist of adjacent nanorods within the oligomer. Therefore, we propose that the adsorbed chiral molecules are able to manipulate the twist angles between the nanorods and thus modulate the CD response of the oligomers.
在紫外区域以外的圆形的二色性(CD ) 的产生具有对开发 chiral 传感器和 chiroptical 设备的大兴趣。此处，我们在可见、近的红外与强壮的 CD 反应为 plasmonic oligomers 的制造表明一个简单、万用的方法光谱范围。oligomers 被被触发制作一起修改半胱氨酸的金 nanorods 的汇编。修改 nanorods 自己没展出明显的 plasmonic CD 信号；然而， oligomers 表演在电浆子回声波长附近的强壮的 CD 乐队。CD 乐队的符号被吸收半胱氨酸分子的 chirality 支配。由调整 oligomers， chiral 分子的集中，或 nanorods 的方面比率的尺寸， CD 紧张并且光谱范围是容易地悦耳的。理论计算建议 oligomers 的那 CD 在 oligomer 以内从邻近的 nanorods 的细微扭曲发源。因此，我们建议吸附的 chiral 分子能操作在 nanorods 之间的扭曲角度并且因此调制 oligomers 的 CD 反应。
