Visualizing Graphene Based Sheets by Fluorescence Quenching Microscopy

TL;DR

This paper introduces a fluorescence quenching microscopy technique that enables quick, substrate-independent visualization of graphene-based sheets, facilitating their characterization and manipulation.

Contribution

The authors develop a novel fluorescence quenching microscopy method that allows substrate-independent, real-time visualization of graphene sheets, including suspended samples, enhancing current imaging capabilities.

Findings

Graphene sheets can be visualized by fluorescence quenching without special substrates.

The method allows visualization of suspended graphene sheets in solution.

Fluorescence dye can be removed after imaging without damaging the sheets.

Abstract

Graphene based sheets have stimulated great interest due to their superior mechanical, electrical and thermal properties. A general visualization method that allows quick observation of these single atomic layers would be highly desirable as it can greatly facilitate sample evaluation and manipulation, and provide immediate feedback to improve synthesis and processing strategies. Here we report that graphene based sheets can be made highly visible under a fluorescence microscope by quenching the emission from a dye coating, which can be conveniently removed afterwards by rinsing without disrupting the sheets. Current imaging techniques for graphene based sheets rely on the use of special substrates. In contrast, the fluorescence quenching mechanism is no longer limited by the types of substrates. Graphene, reduced graphene oxide, or even graphene oxide sheets deposited on arbitrary substrates can now be readily visualized by eye with good contrast for layer counting. Direct observation of suspended sheets in solution was also demonstrated. The fluorescence quenching microscopy offers unprecedented imaging flexibility and could become a general tool for characterizing graphene based materials.