Nitrogen-rich quantum dots (N-dots) were serendipitously synthesized in methanol or aqueous solution at a reaction temperature as low as 50 °C. These N-dots have a small size (less than 10 nm) and contain a high percentage of the element nitrogen, and are thus a new member of quantum-dot family. These N-dots show unique and distinct photoluminescence properties with an increasing percentage of nitrogen compared to the neighboring carbon dots. The photoluminescence behavior was adjusted from blue to green simply through variation of the reaction temperature. Furthermore, the detailed mechanism of N-dot formation was also proposed with the trapped intermediate. These N-dots have also shown promising applications as fluorescent ink and biocompatible staining in C. elegans. Angewandte Chemie International Edition, 2014 a)–c) TEM images of N-dot 1, N-dot 2, N-dot 3 (scale bars 100 nm); Insets are HRTEM images (scale bars 5 nm). d)–f) AFM images and size distributions of N-dot 1, N-dot 2, and N-dot 3. Height profiles are given for the marked white line in the AFM images. |
