Non-blinking Luminescence from Charged Single Graphene Quantum Dots.

Photoluminescence blinking behaviour from single quantum dots under steady illumination is an important but controversial topic. Its occurrence has impeded the use of single quantum dots in bio-imaging. Different mechanisms have been proposed to account for it, although controversial, the most important of which is the non-radiative Auger recombination mechanism whereby photo-charging of quantum dots can lead to the blinking phenomenon. Here, the singly charged trion, which maintains photon emission, including the radiative recombination and non-radiative Auger recombination, leads to fluorescence non-blinking which was observed in photo-charged single graphene quantum dots (GQDs). This phenomenon can be explained in terms of different energy levels in the GQDs, caused by various oxygen-containing functional groups in the single GQDs. The suppressed blinking is due to the filling of trap sites owing to a Coulomb blockade. Our results provide a profound understanding of the special optical properties of GQDs, affording a reference for further in-depth research. This article is protected by copyright. All rights reserved.