Optically transparent diamond electrode for use in ir transmission spectroelectrochemical measurements.
Optically transparent diamond electrode for use in ir transmission spectroelectrochemical measurements.
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用于红外透射光谱电化学测量的光学透明金刚石电极。
DOI：
10.1021/ac071161p
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发表时间：
2007
影响因子：
7.4
通讯作者：
Swain,GregM
中科院分区：
文献类型：
--
作者：
Dai,Yingrui;Proshlyakov,DenisA;Zak,JerzyK;Swain,GregM
报道了一种新的光谱电化学分析方法，该方法利用光学透明的掺硼金刚石薄膜。该膜通过微波辅助化学气相沉积使用4小时生长在未掺杂的Si上沉积，其中使用0.5%CH4/H2源气体混合物和2 ppm B2 H6添加用于硼掺杂。薄膜电极在电磁波谱的中红外和远红外区域具有40 - 60%的透明度。通过扫描电子显微镜、拉曼光谱、X射线衍射、四探针电阻测量、红外光谱和循环伏安法对电极的物理、电学、光学和电化学性能进行了表征。使用水性（Fe（CN）63-/4-、甲基紫精、Ru（NH3）63+/2+和IrCl 62-/3-）和非水性（二茂铁）氧化还原系统评估了该膜的电化学行为。该膜表现出低而稳定的背景电流和几乎可逆的伏安响应所有这些氧化还原体系。使用金刚石/Si光学透明电极（OTE）和薄层透射池记录10 mM Fe（CN）63-/4-在1 M KCl中的光谱电化学响应。在不同的外加电位下记录的差示红外光谱（氧化-还原）表明，Fe（CN）64-在氧化成Fe（CN）63-后，CN的振动模式从2039 cm-1可逆地移动到2116 cm-1。还记录了20 mM二茂铁在0.1 M TBABF 4/CH 3CN中的差IR光谱（氧化减去还原）。在二茂铁氧化为铁时，双环的C-H弯曲模从823 cm-1移动到857 cm-1。这项工作的关键发现是，金刚石OTE为中红外和远红外的水性和非水性氧化还原体系提供了灵敏、可重复和稳定的光谱电化学响应。
A new analytical spectroelectrochemical methodology is reported on that utilizes an optically transparent boron-doped diamond thin film. The film was deposited on undoped Si by microwave-assisted chemical vapor deposition using a 4-h growth with a 0.5% CH4/H2source gas mixture and 2 ppm B2H6added for boron doping. The thin-film electrode possessed a transparency of 40−60% in the mid- and far-IR regions of the electromagnetic spectrum. The physical, electrical, optical, and electrochemical properties of the electrode were characterized by scanning electron microscopy, Raman spectroscopy, X-ray diffraction, four-point probe electrical resistance measurements, IR spectroscopy, and cyclic voltammetry. The film's electrochemical behavior was evaluated using both aqueous (Fe(CN)63-/4-, methyl viologen, Ru(NH3)63+/2+, and IrCl62-/3-) and nonaqueous (ferrocene) redox systems. The film exhibited a low and stable background current and a nearly reversible voltammetric response for all these redox systems. The diamond/Si optically transparent electrode (OTE) and a thin-layer transmission cell were used to record the spectroelectrochemical response for 10 mM Fe(CN)63-/4-in 1 M KCl. Difference IR spectra (oxidized minus reduced), recorded at various applied potentials, showed that the CN vibrational mode at 2039 cm-1for Fe(CN)64-reversibly shifted to 2116 cm-1upon oxidation to Fe(CN)63-, as expected. Difference IR spectra (oxidized minus reduced) were also recorded for 20 mM ferrocene in 0.1 M TBABF4/CH3CN. A shift of the C−H bending mode of the cyclopentadienyl ring from 823 to 857 cm-1occurred upon oxidation of ferrocene to ferricenium. The key finding from the work is that the diamond OTE provides sensitive, reproducible, and stable spectroelectrochemical responses for aqueous and nonaqueous redox systems in the mid- and far-IR.