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

Quantum dots (QDs) with non‐blinking applied in bio‐imaging is important for understanding cellular dynamics by monitoring single particles in living cells. Antibunching is once believed to be applied to identify a single QD, which shows a strong dependence on the atom or ion number. However, recent works indicate that the antibunching alone may not be sufficient to demonstrate that the fluorescence comes from a single QD. To some extent, it is neither necessary nor sufficient for a single QD, though it is absolutely right for a single atom because a single QD is composed of thousands of atoms, which in principle are favorable to the formation of multi‐excitonic states. Blinking behavior, almost unobservable in ensembles due to the averaging, is characteristic of the single QD which owns the quantum effect due to its discrete energy levels. Here, a method of transformation of a single graphene quantum dot from non‐blinking to blinking via catalytic reaction to identify a single QD is reported, which can also help with understanding the catalytic dynamics of a single QD, which is a complementary means of confirming a single QD. The reported technique paves the way to understanding a single QD and its catalytic and kinetic behaviors.

As an emerging bandgap material, antimonene quantum dots (AQDs) have attracted much attention due to their unique structure and outstanding physical and chemical properties. However, the research on the optical properties of AQDs is still in the initial stage and needs further exploration. Herein, the fluorescent AQDs were synthesized by ultrasonic liquid-phase exfoliation, combined with a hydrothermal treatment process. The as-prepared AQDs exhibit good fluorescence characteristics and have a fluorescence quantum yield value of 7.56%. Besides, the AQDs show good stability under different salt concentrations. Especially, the AQDs show high selectivity and rapid detection of Fe3+, CrO42−, and Cr2O72− ions in an aqueous solution with good anti-interference ability. The relatively low limit of detection for Fe3+ based on AQDs was 6.85 µM, and the limits of detection for CrO42−, and Cr2O72− were 23.0 and 5.91 µM, respectively. The mechanism for the fluorescence quenching of the AQDs can be attributed to the synergistic effect of the internal filter effect and the oxidation–reduction reaction between the AQDs and analytes. This work provided a simple synthesis method to easily prepare the AQDs with a larger yield, which can be applied to rapidly detect Fe3+ cation, and CrO42−, and Cr2O72− anions.