Graphene encapsulation enabled high-throughput atom probe tomography of liquid specimens

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Atom probe tomography (APT) traditionally requires vacuum-compatible specimens.
• Imaging hydrated or liquid materials at the atomic scale presents significant challenges.
• Existing methods for preparing liquid samples for high-resolution microscopy are limited.

Purpose of the Study:

• To develop a new method for preparing and imaging liquid specimens using atom probe tomography.
• To enable atomic-resolution analysis of materials in their hydrated state.
• To overcome limitations of current techniques for liquid sample preparation.

Main Methods:

• Graphene encapsulation of liquid specimens on sharpened tips (radius < 75 nm).
• Confirmation of encapsulation using electron microscopy and stimulated emission depletion microscopy.
• Cryogenic freezing and laser-pulsed APT imaging of encapsulated liquid samples.

Main Results:

• Successful encapsulation and APT imaging of water specimens.
• Identification of water-related ions and 3D reconstruction of water volume.
• Demonstration of simultaneous preparation of multiple liquid specimens for high-throughput analysis.

Conclusions:

• The graphene encapsulation method allows for lift-out-free preparation of APT specimens in a hydrated state.
• This technique opens new possibilities for atomic-resolution insights into various liquid materials.
• The method supports high-throughput imaging of liquid samples, accelerating materials research.