Gan Lu, Lim Sharon Xiaodai, Sow Chorng-Haur
Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
Jianqing Experiment School, No. 900, Guyang Rd, Shanghai 10312, China.
ACS Omega. 2022 Mar 16;7(12):10330-10339. doi: 10.1021/acsomega.1c06963. eCollection 2022 Mar 29.
With their special hierarchical fractal and highly symmetric formation, silver dendrites have a large surface area and plentiful active sites at edges, which have allowed them to exhibit unique properties ranging from superhydrophobic surfaces to biosensors. Yet, many suggested synthesis processes either require a long reaction time or risk contamination from sacrificial elements. Limited research in directing while enhancing the growth of these silver dendrites also hinders the application of these unique microstructures as site-selective hydrophobicity of surfaces and location-dependent SERS (surface-enhanced Raman spectroscopy). A possible solution to this is to utilize WO nanocubes as beacons to accelerate and conduct the growth of these silver dendrites through the electrochemical migration process. These nanocubes effortlessly altered the applied electric field distributed between the electrodes, depending on their orientations and positions. As the silver dendrites branched from the nanocubes, the dendrites themselves further concentrated the electric field to encourage the growth of more loose fractal silver dendrites. The combinatory effect successfully directs the growth of silver dendrites along the concentrated electric field paths. Both changes to the electric field and directed growth of silver dendrites are underscored using Multiphysics COMSOL simulations and time-lapse microscopy. This work provided insight into the possibility of designing microstructures to direct and accelerate the growth of silver dendrites.
银树枝晶具有特殊的分级分形和高度对称的结构，具有较大的表面积和边缘丰富的活性位点，这使其表现出从超疏水表面到生物传感器等独特性能。然而，许多建议的合成过程要么需要较长的反应时间，要么存在来自牺牲元素污染的风险。在引导并增强这些银树枝晶生长方面的有限研究，也阻碍了这些独特微结构作为表面的位点选择性疏水性和位置依赖性表面增强拉曼光谱（SERS）的应用。对此的一种可能解决方案是利用WO纳米立方体作为信标，通过电化学迁移过程加速并引导这些银树枝晶的生长。这些纳米立方体根据其取向和位置轻松改变了施加在电极之间的电场分布。当银树枝晶从纳米立方体分支出来时，树枝晶本身进一步集中电场，以促进更多松散分形银树枝晶的生长。这种组合效应成功地引导了银树枝晶沿着集中电场路径生长。使用多物理场COMSOL模拟和延时显微镜突出显示了电场的变化和银树枝晶的定向生长。这项工作为设计微结构以引导和加速银树枝晶生长的可能性提供了见解。
