The Formation of Carbon Dots from D‐Glucose Studied by Infrared Spectroscopy

Carbon dots (C‐dots) obtained from D‐glucose have attracted great interest because of their properties and as a model for understanding the synthesis process and the origin of photoluminescence in carbon‐based nanostructures. Synthesising C‐dots under hydrothermal conditions has become one of the most common methods for their preparation. Understanding the details of this process is quite difficult. To tackle this challenge, we have adopted a multi‐technique approach in our present work. We have correlated different spectroscopic analyses, such as infrared, Raman, fluorescence, NMR, and UV‐Vis, to connect the emissions with specific chemical groups. In particular, in situ infrared analysis as a function of temperature has allowed following the formation of C=C, C=O, and COOH species and the rise of specific emissions. Only weak emissions due to n‐π* transitions are detected upon post‐synthesis thermal annealing. This work was funded and developed within the framework of the project e.INS–Ecosystem of Innovation for Next Generation Sardinia (grant number ECS 00000038), funded by the Italian Ministry for Research and Education (MUR) under the National Recovery and Resilience Plan (NRRP)–MISSION 4 COMPONENT 2, “From research to business” INVESTMENT 1.5, “Creation and strengthening of Ecosystems of innovation”, and construction of “Territorial R&D Leaders”.