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Carbon Dots from Citric Acid and its Intermediates Formed by Thermal Decomposition
Author(s) -
Ludmerczki Robert,
Mura Stefania,
Carbonaro Carlo Maria,
Mandity Istvan M.,
Carraro Massimo,
Senes Nina,
Garroni Sebastiano,
Granozzi Gaetano,
Calvillo Laura,
Marras Sergio,
Malfatti Luca,
Innocenzi Plinio
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201902497
Subject(s) - citric acid , thermal decomposition , fluorescence , chemistry , decomposition , photochemistry , carbon fibers , x ray photoelectron spectroscopy , quenching (fluorescence) , fluorescence spectroscopy , inorganic chemistry , materials science , organic chemistry , chemical engineering , physics , quantum mechanics , composite number , engineering , composite material
Thermal decomposition of citric acid is one of the most common synthesis methods for fluorescent carbon dots; the reaction pathway is, however, quite complex and the details are still far from being understood. For instance, several intermediates form during the process and they also give rise to fluorescent species. In the present work, the formation of fluorescent C‐dots from citric acid has been studied as a function of reaction time by coupling infrared analysis, X‐ray photoelectron spectroscopy, liquid chromatography/mass spectroscopy (LC/MS) with the change of the optical properties, absorption and emission. The reaction intermediates, which have been identified at different stages, produce two main emissive species, in the green and blue, as also indicated by the decay time analysis. C‐dots formed from the intermediates have also been synthesised by thermal decomposition, which gave an emission maximum around 450 nm. The citric acid C‐dots in water show short temporal stability, but their functionalisation with 3‐aminopropyltriethoxysilane reduces the quenching. The understanding of the citric acid thermal decomposition reaction is expected to improve the control and reproducibility of C‐dots synthesis.