Longoni Margherita, Zalaffi Maria Sole, de Ferri Lavinia, Stortini Angela Maria, Pojana Giulio, Ugo Paolo
Department of Molecular Sciences and Nanosystems, University Ca' Foscari of Venice, via Torino 155, 30172 Venice, Italy.
Department of Chemistry, University of Milan, via C. Golgi 19, 20133 Milano, Italy.
Nanomaterials (Basel). 2021 Feb 18;11(2):518. doi: 10.3390/nano11020518.
The electrochemical preparation of arrays of copper ultramicrowires (CuUWs) by using porous membranes as templates is critically revisited, with the goal of obtaining cheap but efficient substrates for surface enhanced Raman spectroscopy (SERS). The role of the materials used for the electrodeposition is examined, comparing membranes of anodized aluminum oxide (AAO) vs. track-etched polycarbonate (PC) as well as copper vs. glassy carbon (GC) as electrode material. A voltammetric study performed on bare electrodes and potentiostatic tests on membrane coated electrodes allowed the optimization of the deposition parameters. The final arrays of CuUWs were obtained by chemical etching of the template, with NaOH for AAO and CHCl for PC. After total etching of the template, SERS spectra were recorded on CuUWs using benzenethiol as SERS probe with known spectral features. The CuUW substrates displayed good SERS properties, providing enhancement factor in the 10-10 range. Finally, it was demonstrated that higher Raman enhancement can be achieved when CuUWs are decorated with silver nanostars, supporting the formation of SERS active hot-spots at the bimetallic interface.
以多孔膜为模板电化学制备铜超微线（CuUWs）阵列的方法被重新审视，目的是获得用于表面增强拉曼光谱（SERS）的廉价且高效的基底。研究了用于电沉积的材料的作用，比较了阳极氧化铝（AAO）膜与径迹蚀刻聚碳酸酯（PC）膜，以及铜与玻璃碳（GC）作为电极材料。对裸电极进行的伏安研究和对膜涂覆电极进行的恒电位测试实现了沉积参数的优化。通过对模板进行化学蚀刻获得最终的CuUWs阵列，AAO用NaOH蚀刻，PC用CHCl蚀刻。模板完全蚀刻后，以具有已知光谱特征的苯硫酚作为SERS探针，在CuUWs上记录SERS光谱。CuUW基底表现出良好的SERS性能，增强因子在10-10范围内。最后，证明了用银纳米星装饰CuUWs时可以实现更高的拉曼增强，这支持了在双金属界面处形成SERS活性热点。
