Photoluminescence mechanism of carbon dots: triggering high-color-purity red fluorescence emission through edge amino protonation

Recently, Prof. Xiaoxia Zhong and her research partner published a research article titled “Photoluminescence mechanism of carbon dots: triggering high-color-purity red fluorescence emission through edge amino protonation” in Nature Communications, a high impact international journal.

Fig.1 Mechanism of the red PL emission of the CDs.

Due to complex structure and surface functionalities, photoluminescence mechanisms of Carbon Dots are unknown, and it is challenging to synthesize Carbon Dots to achieve the desired optical properties.

Herein, Carbon Dots simultaneously exhibit high-colour-purity (FWHM~24 nm) long-wavelength one-photon fluorescence emission at 620 nm and NIR induced two-photon fluorescence emission at 630 and 680 nm are prepared by edge amino protonation treatment. Systematic analysis reveals that the protonation of 2,3-diaminophenazine changes the molecular state of Carbon Dots, decreases the photon transition band gap, and triggers red fluorescence emission with the dramatically narrowed peak width. As the oxidation products of reactant o-phenylendiamine, the emergence of 2,3-diaminophenazine as a photoluminescence determiner suggests that fluorophore products of precursor conversion are viable determinants of the desired luminescence properties of Carbon Dots.

Here, we show a new way for predicting and controlling photoluminescence properties of Carbon Dots, and may guide the development of tunable Carbon Dots for a broad range of applications.

In this work, postdoctor Qing Zhang is the first author and co-corresponding author. Prof. Xiaoxia Zhong is the corresponding author. The cooperator Prof. Kostya (Ken) Ostrikov comes from Queensland University of Technology. This research is supported by the National Natural Science Foundation of China (Grant No. 12175141) Natural Science Foundation of Shanghai(Grant No. 21ZR1435200), National Key Research and Development Program of China (Grant No. 2018YFA0306304) received by X.X.Z. and China Postdoctoral Science Foundation (Grant Nos.2020TQ0197) received by Q. Z.

Links: https://www.nature.com/articles/s41467-021-27071-4