A High-Q AFM Sensor Using a Balanced Trolling Quartz Tuning Fork in the Liquid

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Quartz tuning forks (QTFs) are excellent force sensors for atomic force microscopy (AFM) due to their stiffness and self-sensing capabilities.
• However, their application in liquids is limited by bulky structures and exposed electrodes, which degrade performance.

Purpose of the Study:

• To introduce a novel balanced trolling quartz tuning fork (BT-QTF) method to overcome the limitations of traditional QTFs in liquid environments.
• To enable stable and sensitive AFM imaging of biological samples, ionic liquids, and electrochemical reactions in situ.

Main Methods:

• Developed a BT-QTF by attaching identical probes to both prongs of a QTF, with only one probe immersed in the liquid.
• Presented a theoretical model to analyze the sensing performance of the BT-QTF in liquid.
• Conducted experimental analysis of the BT-QTF's sensing performance.

Main Results:

• The BT-QTF method significantly reduces hydrodynamic interactions in liquids.
• Maintained a high quality factor and constant resonance frequency, enabling stable small vibrations.
• Successfully applied the BT-QTF for AFM imaging of various samples in liquid environments.

Conclusions:

• The BT-QTF is a feasible and effective method for high-performance AFM imaging in liquids.
• This technique overcomes previous limitations, expanding the scope of QTF applications in sensitive environments.