Nitrogen-doped diamond-like carbon as optically transparent electrode for infrared attenuated total reflection spectroelectrochemistry

摘要

This contribution describes the development of nitrogen-doped diamond-like carbon (N-DLC) thinnfilms for multi-reflection mid-infrared (MIR) attenuated total reflectance (IR-ATR)nspectroelectrochemistry. N-DLC coatings were deposited using pulsed laser deposition (PLD)ninvolving the ablation of a high purity graphite target. The DLC matrix was further modified bynablating the target in the presence of nitrogen gas. This technique offers the advantage of depositingnthin films at room temperature, thereby enabling coating of temperature-sensitive substrates includingne.g., MIR waveguides. The resulting films were analyzed with X-ray photoelectron spectroscopy (XPS),nand determined to be composed of carbon, nitrogen, and adventitious oxygen. Raman spectroscopicnstudies indicate that the addition of nitrogen induces further clustering and ordering of the sp2-nhybridized carbon phase. The electrochemical activity of PLD fabricated N-DLC films was verifiednusing the Ru(NH3)3+/2+ redox couple, and was determined to be comparable with that of other carbonbasednelectrodes. In situ spectroelectrochemical studies involving N-DLC coated zinc selenide (ZnSe)nMIR waveguides provided evidence concerning the oxidation of N-DLC at anodic potentials in 1 MnHClO4 solutions. Finally, the electropolymerization of polyaniline (PAni) was performed at N-DLCmodifiednwaveguide surfaces, which enabled spectroscopic monitoring of the electropolymerization, asnwell as in situ studying the structural conversion of PAni at different potentials.