Tuneable properties of carbon quantum dots by different synthetic methods

Abstract Carbon quantum dots (CQD) were prepared from three different precursors and by bottom-up synthesis methods: classical pyrolysis of citric acid (CAP), microwave irradiation glucose (GM), hydrothermal treatment glucosamine hydrochloride (GAH). CQD further functionalized using various nitrogen-containing compounds: 6-aminohexanoic acid, 1,6-diaminohexane, N-octylamine, dimethylamine, tryptophan. Special attention was dedicated to investigate how the combination synthetic method starting material affected nature properties CQD. The analysis indicated that CAP good candidates for covalent post-functionalization, GM allowed an easy passivation, GAH permitted direct introduction nitrogen into core. size distribution showed a core–shell structure with aminoacid irradiation, whereas thermal decomposition evidenced degradation functionalizing molecules presence pyridinic pyrrolic after synthesis. Photoluminescence spectra revealed important differences between techniques, related occurrence surface states, highest fluorescence yield hydrothermally These approaches led can be exploited in many fields energy conversion sensing.