Large-scale fabrication of heavy doped carbon quantum dots with tunable-photoluminescence and sensitive fluorescence detection

Carbon quantum dots (CQDs) have been intensively investigated due to their interesting electrochemical and photoluminescent properties. Here, we report a novel method for large-scale preparation of heavy doped CQDs with tunable photoluminescence. In the present synthetic process, the carbon nanoparticles from Chinese ink were oxidized and cut simultaneously using a mature process to obtain oxidized-CQDs as precursors, and then the heteroatom (N, S or Se) doped CQDs were obtained by a one-step hydrothermal reduction and in situ doping treatment. The heavy doped CQDs are just 1–6 nm size, and have improved photoluminescence with different emission wavelengths, higher quantum yield, longer lifetime and good photostability. Further experiments suggested that these N and S doped CQDs were very sensitive for the detection of Cu2+ and Hg2+, respectively.