| Graphene quantum dots(GQDs) have triggered tremendous attention as a new class of “zero-dimensional” carbon nanomaterials. Owing to the remarkable quantum-confinement and edge effects, the 0D GQDs are superior to 2D graphene in many aspects. Recently, these as-reported GQDs can not be defined as “pristine” GQDs who have an “oxygen defects-free” structure. However, it is of scientific importance to prepare GQDs with this particular structure, for both optimizing their optical properties and helping in their photovoltaic applications. Herein, a new strategy for the facile preparation of GQDs with nanocrystalline graphite composition is reported, the main contents and the results of this work are as following:(1) Fluorescent carbon nanodots(CNDs) with 1-5 nm size distribution were obtained through a microwave-assisted pyrolysis of the carbon source(glycerol), during which various oxygenous groups were introduced along these CNDs. A thermal-reduction process by microwave heating was employed then. Due to the complicacy of the whole process, a fraction of analogous graphene quantum dots(Ana-GQDs) with negligible oxygenous defects can be formed and existed in the whole products. They were successfully acquired through a solvents-induced interface separation.(2) The as-separeated products were studied by a series of characterization. The results showed that Ana-GQDs have a sp2 hybridized carbon atom dominant structure whose content is up to 90.92%. Meanwhile, the oxgenous ratio is negligible(9.08%). The type of carbon atoms in Ana-GQDs is very similar to that in graphene, which are dominated by the sp2(graphitic) π bonds.(3) The as-prepared Ana-GQDs were integrated into a photodetector as the electron-acceptors. For better studying the effect of Ana-GQDs, a parallel device using PCBM, a typical derivative of C60, was also perfomed. The results showed that Ana-GQDs are potential to be a new kind of low-cost electron-acceptors for photovoltaics. |
