Gabinet Uri R, Lee Changyeon, Kim Na Kyung, Hulman Martin, Thompson Sarah M, Kagan Cherie R, Osuji Chinedum O
Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States.
J Phys Chem Lett. 2022 Sep 1;13(34):7994-8001. doi: 10.1021/acs.jpclett.2c01819. Epub 2022 Aug 19.
Molybdenum disulfide (MoS) nanosheets exhibit anisotropic optical and electronic properties, stemming from their shape and electronic structure. Unveiling this anisotropy for study and usage in materials and devices requires the ability to control the orientation of dispersed nanosheets, but to date this has proved a challenging proposition. Here, we demonstrate magnetic field driven alignment of MoS nanosheets in a liquid crystal (LC) polymer and unveil the optical properties of the resulting anisotropic assembly. Nanosheet optical anisotropy is observed spectroscopically by Raman and direction-dependent photoluminescence (PL) measurements. Resulting data indicate significantly lower PL emission due to optical excitation with electric field oscillation out of plane, parallel to the MoS -axis, than that associated with perpendicular excitation, with the dichroic ratio / = 3. The approach developed here provides a useful route to elucidate anisotropic optical properties of MoS nanosheets and to utilize such properties in new materials and devices.
二硫化钼（MoS）纳米片呈现出各向异性的光学和电子特性，这源于它们的形状和电子结构。要揭示这种各向异性以便在材料和器件中进行研究和应用，需要具备控制分散纳米片取向的能力，但迄今为止，这已证明是一项具有挑战性的任务。在此，我们展示了二硫化钼纳米片在液晶（LC）聚合物中的磁场驱动排列，并揭示了所得各向异性组件的光学特性。通过拉曼光谱和与方向相关的光致发光（PL）测量，从光谱上观察到纳米片的光学各向异性。所得数据表明，与垂直激发相比，当电场振荡在平面外且平行于MoS轴进行光学激发时，光致发光发射显著降低，二向色比I⊥/I∥ = 3。这里开发的方法为阐明二硫化钼纳米片的各向异性光学特性以及在新材料和器件中利用这些特性提供了一条有用的途径。
