Study on construction of red carbon nanodots from O-phenylenediamine

Red emission carbon nanodots (CNDs) have a promising prospect in bioimaging field because of their low-toxicity, good compatibility, slight photo damage and low interference. However, it is hard to prepare red photoluminescence (PL) CNDs. The CNDs prepared from o-phenylenediamine (oPD) by solvothermal usually emit green fluorescence (FL). The emission wavelength only turned 32 nm red-shift after oxidative polymerization by introducing FeCl3 as catalyst. While, as terephthalic acid (TA) was introduced into the reaction, the red-shift exceeded 100 nm and the red emission was successfully achieved. Thus, according to the special structure of precursors, a donor-π-acceptor (D-π-A) structure strategy was proposed to synthesize red emission CNDs.