Direct Observations of Graphene Dispersed in Solution by Twilight Fluorescence Microscopy

Area of Science:

• Materials Science
• Nanotechnology
• Optical Microscopy

Background:

• Observing nanomaterials like graphene and graphene oxide (GO) in solution presents challenges.
• Existing microscopy techniques may lack the resolution or contrast needed for detailed in-situ analysis.

Purpose of the Study:

• To develop and demonstrate a novel microscopy technique for direct visualization of graphene and GO in liquid environments.
• To characterize the imaging capabilities of the new method for differentiating graphene from GO and observing their structures and dynamics.

Main Methods:

• Development of twilight fluorescence (TwiF) microscopy utilizing a fluorescent dye and a specialized cell.
• Imaging nanocarbon dispersions within a few hundred micrometers of a glass surface.
• Utilizing optical processes like absorption, energy transfer, and altered fluorophore chemistry for visualization.

Main Results:

• Direct imaging of individual graphene and GO sheets with sizes ranging from submicron to submillimeter.
• Clear differentiation between graphene and GO when coexisting in the same solution.
• Visualization of layering, network structures, real-time motion in flow, and in-situ adhesion processes.

Conclusions:

• Twilight fluorescence (TwiF) microscopy is a powerful new tool for observing graphene and GO in solution.
• The technique allows for detailed structural and dynamic analysis of these nanomaterials.
• TwiF microscopy offers selectable wavelengths for versatile imaging based on dye choice.