Cathodic electropaint insulated tips for electrochemical scanning tunneling microscopy

Area of Science:

• Electrochemistry
• Materials Science
• Nanotechnology

Background:

• Scanning tunneling microscopy (STM) is a powerful surface analysis technique.
• Electrochemical STM (EC-STM) allows for imaging under electrochemical conditions.
• Developing robust, insulated tips is crucial for EC-STM in electrolyte solutions.

Purpose of the Study:

• To present a novel method for preparing electrically insulated tungsten tips for in situ EC-STM.
• To characterize the performance of these insulated tips.
• To demonstrate their capability for high-resolution imaging in electrolyte.

Main Methods:

• Electrocoating tungsten tips with an organic cathodic electropaint solution at low voltages.
• Characterization using cyclic voltammetry and electrochemical STM (EC-STM).
• Imaging of monocrystalline Au surfaces and cobalt(II) porphyrin adlayers under potential control in dilute HClO4.

Main Results:

• The fabricated tungsten tips exhibited low Faradaic leakage currents.
• High-resolution STM imaging was achieved in electrolyte solution.
• Atomic and molecular resolution images of gold terraces and porphyrin adlayers were obtained.

Conclusions:

• The developed procedure provides a fast and reproducible method for generating insulated tungsten tips.
• These tips are suitable for high-quality EC-STM imaging experiments.
• The method advances the application of EC-STM for surface studies in electrochemical environments.