Effective Insulation of Scanning Tunneling Microscopy Tips for Electrochemical Studies Using an Electropainting Method

We report here on a new, straightforward, and effective method for insulating etched and cut Pt/Ir scanning tunneling microscopy (STM) tips for in situ electrochemical studies. The coating was formed by electrophoretic painting and subsequent heating. It covered all but the very end of the tip, which may be attributed to shrinking of the polymer during heating. We have characterized these tips by voltammetric methods, scanning electron microscopy, and by in situ STM imaging.