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Article

Reversible Aggregation of Molecular-Like Fluorophores Driven by Extreme pH in Carbon Dots

Laboratorio di Scienza dei Materiali e Nanotecnologie, CR-INSTM, Dipartimento di Chimica e Farmacia, Università di Sassari, Via Vienna 2, 07100 Sassari, Italy
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Materials 2020, 13(16), 3654; https://doi.org/10.3390/ma13163654
Received: 1 July 2020 / Revised: 7 August 2020 / Accepted: 13 August 2020 / Published: 18 August 2020
The origin of carbon-dots (C-dots) fluorescence and its correlation with the dots structure still lack a comprehensive model. In particular, the core-shell model does not always fit with the experimental results, which, in some cases, suggest a molecular origin of the fluorescence. To gain a better insight, we have studied the response of molecular-like fluorophores contained in the C-dots at extreme pH conditions. Citric acid and urea have been employed to synthesize blue and green-emitting C-dots. They show a different emission as a function of the pH of the dispersing media. The photoluminescence has been attributed to molecular-like fluorophores: citrazinic acid and 4-hydroxy-1H-pyrrolo[3,4-c]-pyridine-1,3,6-(2H,5H)-trione. 3D and time-resolved photoluminescence, ultraviolet–visible (UV–vis) spectroscopy, and dynamic light scattering have been used to determine the aggregation state, quantum yield and emission properties of the C-dots. The dependence of the C-dots blue and green components on the chemical environment indicates that the origin of fluorescence is due to molecular-like fluorophores. View Full-Text
Keywords: nanomaterials; carbon-dots; photoluminescence; spectroscopy nanomaterials; carbon-dots; photoluminescence; spectroscopy
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MDPI and ACS Style

Mura, S.; Stagi, L.; Ludmerczki, R.; Malfatti, L.; Innocenzi, P. Reversible Aggregation of Molecular-Like Fluorophores Driven by Extreme pH in Carbon Dots. Materials 2020, 13, 3654. https://doi.org/10.3390/ma13163654

AMA Style

Mura S, Stagi L, Ludmerczki R, Malfatti L, Innocenzi P. Reversible Aggregation of Molecular-Like Fluorophores Driven by Extreme pH in Carbon Dots. Materials. 2020; 13(16):3654. https://doi.org/10.3390/ma13163654

Chicago/Turabian Style

Mura, Stefania, Luigi Stagi, Robert Ludmerczki, Luca Malfatti, and Plinio Innocenzi. 2020. "Reversible Aggregation of Molecular-Like Fluorophores Driven by Extreme pH in Carbon Dots" Materials 13, no. 16: 3654. https://doi.org/10.3390/ma13163654

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