In Situ Surface Roughness Analysis of Electrodeposited Co Films in an Ionic Liquid Using Electrochemical Surface Plasmon Resonance: Effect of Leveling Additives
In Situ Surface Roughness Analysis of Electrodeposited Co Films in an Ionic Liquid Using Electrochemical Surface Plasmon Resonance: Effect of Leveling Additives
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DOI：
10.1149/1945-7111/ac13d1
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发表时间：
2021-07
影响因子：
3.9
通讯作者：
Naoya Nishi;K. Ezawa;T. Sakka
中科院分区：
文献类型：
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作者：
Naoya Nishi;K. Ezawa;T. Sakka
采用电化学表面等离子体共振技术（ESPR）原位分析了两种调平剂硫脲（TU）和香豆素（CM）对离子液体（IL） 1-丁基-3-甲基咪唑双（三氟甲磺酰）酰胺（C4mimTFSA）在金表面电沉积钴的影响，并记录了SPR共振角（Δθ）和循环伏安图。两种添加剂的Δθ行为不同于无添加剂的情况，也不同于无添加剂的情况。在TU的情况下，Co阴极沉积引起的Δθ正位移大于无添加剂的情况。即使在随后由于Co阳极溶解导致负Δθ位移之后，Δθ仍保持正，不会返回到原始值。这表明TU促进了金的溶解，使金电极表面变得粗糙。相反，在CM的情况下，Co阴极沉积引起的Δθ正位移小于无添加剂情况。利用菲涅耳反射率进行的模型分析表明，CM实际上在电沉积的初始过程中就使Co膜表面光滑。这些发现表明，ESPR可以原位感知电沉积过程中表面粗糙度的变化，其量级为Å。
The effect of two leveling additives, thiourea (TU) and coumarin (CM), on cobalt electrodeposition process in an ionic liquid (IL), 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) amide (C4mimTFSA), at the gold surface has been analyzed in situ using electrochemical surface plasmon resonance (ESPR), in which the SPR resonance angle (Δθ) has been recorded simultaneously with cyclic voltammograms. The two additives show Δθ behaviors different from the additive-free case and from each other. In the case of TU, the positive Δθ shift due to Co cathodic deposition is larger than the additive-free case. Even after the subsequent negative Δθ shift due to Co anodic dissolution, Δθ remains positive not returning to the original value. This indicates that the dissolution of gold facilitated by TU roughens the surface of the gold electrode. In contrast, in the case of CM, the positive Δθ shift due to Co cathodic deposition is smaller than the additive-free case. A model analysis using Fresnel reflectivity has revealed that CM actually smooths the surface of the Co film even in the initial process of the electrodeposition. These findings illustrate that ESPR can sense in situ the surface roughness change during electrodeposition on the order of Å.