Xu Ye, Ge Dengteng, Calderon-Ortiz Gabriel A, Exarhos Annemarie L, Bretz Coline, Alsayed Ahmed, Kurz Dave, Kikkawa J M, Dreyfus Remi, Yang Shu, Yodh A G
School of Mechanical Engineering and Automation and Center of Soft Matter Physics and its Applications, Beihang University, Beijing 100191, P.R. China.
Nanoscale. 2020 Mar 21;12(11):6438-6448. doi: 10.1039/c9nr09598e. Epub 2020 Mar 9.
Conductive and transparent coatings consisting of silver nanowires (AgNWs) are promising candidates for emerging flexible electronics applications. Coatings of aligned AgNWs offer unusual electronic and optical anisotropies, with potential for use in micro-circuits, antennas, and polarization sensors. Here we explore a microfluidics setup and flow-induced alignment mechanisms to create centimeter-scale highly conductive coatings of aligned AgNWs with order parameters reaching 0.84, leading to large electrical and optical anisotropies. By varying flow rates, we establish the relationship between the shear rate and the alignment and investigate possible alignment mechanisms. The angle-dependent sheet resistance of the aligned AgNW networks exhibits an electronic transport anisotropy of ∼10× while maintaining low resistivity (<50 Ω sq) in all directions. When illuminated, the aligned AgNW coatings exhibit angle- and polarization-dependent colors, and the polarized reflection anisotropy can be as large as 25. This large optical anisotropy is due to a combination of alignment, polarization response, and angle-dependent scattering of the aligned AgNWs.
由银纳米线（AgNWs）组成的导电透明涂层是新兴柔性电子应用的有前途的候选材料。排列的AgNWs涂层具有不寻常的电子和光学各向异性，有用于微电路、天线和偏振传感器的潜力。在此，我们探索一种微流体装置和流动诱导排列机制，以制备厘米级排列的AgNWs高导电涂层，其有序参数达到0.84，从而产生大的电学和光学各向异性。通过改变流速，我们建立了剪切速率与排列之间的关系，并研究了可能的排列机制。排列的AgNW网络的与角度相关的薄层电阻表现出约10倍的电子传输各向异性，同时在所有方向上保持低电阻率（<50Ω/sq）。当被光照时，排列的AgNW涂层呈现出与角度和偏振相关的颜色，并且偏振反射各向异性可高达25。这种大的光学各向异性是排列、偏振响应以及排列的AgNWs的角度相关散射共同作用的结果。
