Doping of low-dimensional graphitic materials, including graphene, graphene quantum dots and single-wall carbon nanotubes with nitrogen, sulfur or boron can significantly change their properties. We report that simple fluorination followed by annealing in a dopant source can superdope low-dimensional graphitic materials with a high level of N, S or B. The superdoping results in the following doping levels: (i) for graphene, 29.82, 17.55 and 10.79 at% for N-, S- and B-doping, respectively; (ii) for graphene quantum dots, 36.38 at% for N-doping; and (iii) for single-wall carbon nanotubes, 7.79 and 10.66 at% for N- and S-doping, respectively. As an example, the N-superdoping of graphene can greatly increase the capacitive energy storage, increase the efficiency of the oxygen reduction reaction and induce ferromagnetism. Furthermore, by changing the degree of fluorination, the doping level can be tuned over a wide range, which is important for optimizing the performance of doped low-dimensional graphitic materials.

A hydrothermal approach was developed for the synthesis of N-doped graphene quantum dots (N-GQDs) by cutting N-doped graphene. The N-GQDs obtained have a N/C atomic ratio of ca. 5.6% and diameter of 1–7 nm. The photoluminescence (PL) properties of the N-GQDs were investigated. It was found that the N-GQDs possess bright blue PL and excellent upconversion PL properties.

The long spin diffusion length makes graphene very attractive for novel spintronic devices and thus has triggered a quest for integrating the charge and spin degrees of freedom. However, ideal graphene is intrinsic non-magnetic, due to a delocalized π bonding network. Therefore, synthesis of ferromagnetic graphene or its derivatives with high magnetization is urgent due to both fundamental and technological importance. Here we report that N-doping can be an effective route to obtain a very high magnetization of ca. 1.66 emu/g and can make graphene oxide (GO) to be ferromagnetism with a Curie-temperature of 100.2 K. Clearly, our findings can offer the easy realization of ferromagnetic GO with high magnetization, therefore, push the way for potential applications in spintronic devices.