Facile production of graphene quantum dots using a molecular adhesive membrane filter

Despite the myriad of studies on graphene quantum dots (GQDs), the commercialization of GQDs has been extremely limited until recently. The biggest bottleneck is the absence of a method for the mass production of GQDs. In this paper, we report a facile method for separating GQDs from chemically modified graphene suspensions using a filter paper embedded with polydopamine nanoparticles. The polydopamine nanoparticles, which have excellent molecular adhesion, interact more preferably with graphene oxide (GO) than with GQDs owing to the larger size of GO particles and high ratio of oxygenated functional groups in GO. We analyze the electron diffraction patterns, photoluminescence properties, and diameter/height profiles of the collected GQDs and conclude that the proposed separation technique yields high-purity GQDs. We believe that this technology can revolutionize the GQD field and relevant applications in fuel cells, semiconductors, bioimaging, and biosensing.