An approach which allows both electrochemical studies and surface enhanced infrared characterization of electrodeposited Cytochrome C is presented. This approach is based on in-plane disordered arrays of resonant slits engraved in Au substrates using focused ion beam. For light-polarized perpendicular to the slit, the reflectivity spectra of the slit arrays show dips related to the excitation of the slit plasmon resonance, whose position depends on the slit length. Due to the presence of the continuous Au layer around the slits, the very same substrates can be used to perform electrochemical studies. By varying the slit length, we have tuned the plasmon resonance to match the absorption bands of electrodeposited Cytochrome C, demonstrating the detection of minute amounts of this protein, all the way down to a single monolayer.

提出了一种允许电化学研究和表面增强的电沉积细胞色素 C 红外表征的方法。这种方法基于使用聚焦离子束在 Au 基板上雕刻的共振狭缝的面内无序阵列。对于垂直于狭缝的光偏振，狭缝阵列的反射率光谱显示出与狭缝等离子体共振激发相关的下降，其位置取决于狭缝长度。由于狭缝周围存在连续的 Au 层，因此可以使用完全相同的基板进行电化学研究。通过改变狭缝长度，我们调整了等离子体共振以匹配电沉积的细胞色素 C 的吸收带，证明检测到微量的这种蛋白质，一直到单个单层。