The effects of various molecular weight of passivator on the photoluminescence properties of graphene quantum dots

Here, we realize manipulation of photoluminescence (PL) intensity of GQDs through various molecular weight of surface passivator. With the increase of passivator molecular weight, only the PL intensity increases. However, the peak positions and half-peak width of spectral line remain unchanged. Our results reveal that surface passivation with larger molecular weight only weakens the chemical activity of graphene quantum dots (GQDs) and the π-π stacking interaction between GQDs, but exerts less impact on GQDs intrinsic energy gap. Therefore, the weaker π-π stacking interaction and chemical activity induce the weaker non-radiative recombination, leading to enhanced fluorescence from radiative recombination.