Researchers (from University of California, Riverside) suggest a new simple method to count graphene sheets. Usually, when graphene is made by chemical vapor deposition (CVD) it results in multiple layers of sheets, and some defects and wrinkles. Current techniques to count the sheets (such as Raman and atomic force microscopy) are limited in size and need calibration.
The new method exploits the fact that graphene quenches fluorescence. The idea is to coat an area of graphene on a surface with a fluorescent polymer dye to allow visualization with a simple fluorescence microscope. The data processing is then quite straightforward.