Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849-5312, United States.
Langmuir. 2011 Feb 1;27(3):878-81. doi: 10.1021/la104225w. Epub 2010 Dec 27.
We report the synthesis of Ag-Au alloy gradients on stainless steel substrates using bipolar electrodeposition (BP-ED), a technique based on the existence of a potential gradient at the interface of a bipolar electrode (BPE) and an electrolytic solution. The interfacial potential gradient causes the rates of electrodeposition of Ag and Au to vary along the length of the BPE, leading to the electrodeposition of a chemical concentration gradient. The surface morphology of the electrodeposits was characterized using scanning electron microscopy (SEM), and their chemical composition was determined using energy dispersive X-ray spectroscopy (EDX). Self-assembled monolayers of a Raman-active probe molecule (benzene thiol) were allowed to form on the surface of the alloy gradients, and confocal Raman microscopy was employed to determine the alloy composition that resulted in the maximum surface enhanced Raman scattering (SERS) intensity. An alloy composition of ca. 70% Ag/30% Au was found to be optimum for SERS excited using 514.5 nm radiation, and it is explained on the basis of composition-dependent changes in the local surface plasmon resonance (LSPR) of the electrodeposited Ag-Au alloy.
我们报告了使用双极电沉积（BP-ED）在不锈钢基底上合成 Ag-Au 合金梯度，该技术基于双极电极（BPE）和电解液界面处存在电位梯度。界面电位梯度导致 Ag 和 Au 的沉积速率沿着 BPE 的长度变化，从而导致化学浓度梯度的沉积。使用扫描电子显微镜（SEM）对电沉积物的表面形态进行了表征，并使用能量色散 X 射线光谱（EDX）确定了它们的化学成分。允许拉曼活性探针分子（苯硫醇）的自组装单层在合金梯度的表面形成，并使用共焦拉曼显微镜确定导致最大表面增强拉曼散射（SERS）强度的合金组成。发现约 70%Ag/30%Au 的合金组成对于使用 514.5nm 辐射激发的 SERS 是最佳的，这是基于电沉积 Ag-Au 合金的局部表面等离子体共振（LSPR）的组成依赖性变化来解释的。
