Kelvin probe force microscopy in nonpolar liquids

Area of Science:

• Surface Science
• Nanotechnology
• Electrochemistry

Background:

• Work function is a fundamental property of materials, crucial for understanding surface phenomena.
• Measuring work function changes at solid-liquid interfaces presents unique challenges.
• Kelvin probe force microscopy (KPFM) is a powerful tool for nanoscale surface potential mapping.

Purpose of the Study:

• To develop and validate a method for measuring work function changes of gold in decane using KPFM.
• To investigate the chemisorption of hexadecanethiol on gold surfaces in a liquid environment.
• To establish reliable procedures for studying local reactions at solid-liquid interfaces.

Main Methods:

• Utilized Kelvin probe force microscopy (KPFM) to measure work function changes of gold in nonpolar liquid decane.
• Employed two distinct routes: maintaining a constant tip work function and using structured surfaces with inert references.
• Investigated hexadecanethiol chemisorption on gold surfaces.

Main Results:

• Successfully measured work function shifts of gold upon hexadecanethiol chemisorption in decane.
• Obtained consistent results using two different KPFM measurement strategies (Route I: -1.33 eV ± 0.07 eV; Route II: -1.46 eV ± 0.04 eV).
• Results showed excellent agreement with literature values obtained via ultraviolet photoemission spectroscopy (UPS).

Conclusions:

• Validated KPFM as a viable technique for quantifying work function changes in liquid environments.
• The developed methods provide new avenues for studying interfacial phenomena and chemical reactions at the nanoscale.
• This research advances the understanding of solid-liquid interfaces in nanotechnology and electrochemistry.