Nanostructured Black Silicon as a Stable and Surface-Sensitive Platform for Time-Resolved In Situ Electrochemical...

Area of Science:

• Surface science
• Electrochemistry
• Spectroscopy

Background:

• Attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) is crucial for studying interfacial chemistry.
• Existing nanostructured metallic films lack stability under electrochemical conditions, limiting in situ analysis.
• A need exists for robust substrates for reliable electrochemical ATR-SEIRAS.

Purpose of the Study:

• To introduce a novel black silicon-based substrate for enhanced in situ electrochemical ATR-SEIRAS.
• To demonstrate the substrate's advantages in stability, sensitivity, and conductivity over traditional materials.
• To enable high time-resolution kinetic and mechanistic studies of electrochemical interfaces.

Main Methods:

• Fabrication of etched black silicon internal reflection elements with gold coatings.
• Electrochemical potential-dependent adsorption/desorption studies using 4-methoxypyridine.
• Utilizing rapid- and step-scan Fourier transform infrared (FTIR) spectroscopy for time-resolved measurements.

Main Results:

• Black silicon substrates exhibit superior stability, sensitivity, and conductivity compared to Au on Si and Au on ITO.
• The low sheet resistance of black silicon enhances electrochemical cell time resolution.
• Adsorption kinetics were found to be diffusion-limited, allowing determination of molecular area and confirming a single adsorption mode.

Conclusions:

• Black silicon-based substrates significantly enhance performance for both steady-state and time-resolved in situ electrochemical ATR-SEIRAS.
• This platform facilitates advanced kinetic and mechanistic investigations of electrochemical interfaces.
• The developed substrate offers a powerful tool for understanding interfacial processes under electrochemical bias.