▎ 摘　　要

Graphene quantum dots (GQDs) with quantum confinement and size effect are proposed to be applicable in photovoltaic, nanodevices, and so on, due to extraordinary electronic and optical properties. Here we report a facile approach to synthesize gram-scale GQDs from active carbon atoms, which are obtained via the deflagration reaction of polytetrafluoroethylene (PTFE) and Si, growing from high- to low-temperature zones when traveling through the deflagration flame in a short time with releasing gas as the carrier medium. The prepared GQDs were aggregated into carbon nanospheres; thus, Hummer's method was utilized to exfoliate the GQD aggregations into individual GQDs. We show that the length of GQDs is similar to 10 nm and the exfoliated GQDs solution presents an obvious fluorescence effect with a strong emission peak at 570 at 460 nm excitation. And these GQDs are demonstrated to be excellent probes for cellular imaging. Furthermore, we propose a growth mechanism based on computer simulation, which is well verified by experimental reproduction. Our study opens up a promising route for high-yield and high-quality GQDs, as well as other various quantum dots.